Index: head/sys/contrib/zstd/Makefile =================================================================== --- head/sys/contrib/zstd/Makefile (revision 330893) +++ head/sys/contrib/zstd/Makefile (revision 330894) @@ -1,348 +1,346 @@ # ################################################################ # Copyright (c) 2015-present, Yann Collet, Facebook, Inc. # All rights reserved. # # This source code is licensed under both the BSD-style license (found in the # LICENSE file in the root directory of this source tree) and the GPLv2 (found # in the COPYING file in the root directory of this source tree). # ################################################################ PRGDIR = programs ZSTDDIR = lib BUILDIR = build ZWRAPDIR = zlibWrapper TESTDIR = tests FUZZDIR = $(TESTDIR)/fuzz # Define nul output VOID = /dev/null ifneq (,$(filter Windows%,$(OS))) EXT =.exe else EXT = endif .PHONY: default default: lib-release zstd-release .PHONY: all all: | allmost examples manual .PHONY: allmost allmost: allzstd $(MAKE) -C $(ZWRAPDIR) all #skip zwrapper, can't build that on alternate architectures without the proper zlib installed .PHONY: allzstd allzstd: $(MAKE) -C $(ZSTDDIR) all $(MAKE) -C $(PRGDIR) all $(MAKE) -C $(TESTDIR) all .PHONY: all32 all32: $(MAKE) -C $(PRGDIR) zstd32 $(MAKE) -C $(TESTDIR) all32 .PHONY: lib lib: @$(MAKE) -C $(ZSTDDIR) $@ .PHONY: lib-release lib-release: @$(MAKE) -C $(ZSTDDIR) .PHONY: zstd zstd: @$(MAKE) -C $(PRGDIR) $@ cp $(PRGDIR)/zstd$(EXT) . .PHONY: zstd-release zstd-release: @$(MAKE) -C $(PRGDIR) cp $(PRGDIR)/zstd$(EXT) . .PHONY: zstdmt zstdmt: @$(MAKE) -C $(PRGDIR) $@ cp $(PRGDIR)/zstd$(EXT) ./zstdmt$(EXT) .PHONY: zlibwrapper zlibwrapper: $(MAKE) -C $(ZWRAPDIR) test +.PHONY: check +check: shortest + .PHONY: test shortest test shortest: - $(MAKE) -C $(PRGDIR) allVariants + $(MAKE) -C $(PRGDIR) allVariants MOREFLAGS="-g -DZSTD_DEBUG=1" $(MAKE) -C $(TESTDIR) $@ .PHONY: examples examples: CPPFLAGS=-I../lib LDFLAGS=-L../lib $(MAKE) -C examples/ all .PHONY: manual manual: $(MAKE) -C contrib/gen_html $@ .PHONY: cleanTabs cleanTabs: cd contrib; ./cleanTabs .PHONY: clean clean: @$(MAKE) -C $(ZSTDDIR) $@ > $(VOID) @$(MAKE) -C $(PRGDIR) $@ > $(VOID) @$(MAKE) -C $(TESTDIR) $@ > $(VOID) @$(MAKE) -C $(ZWRAPDIR) $@ > $(VOID) @$(MAKE) -C examples/ $@ > $(VOID) @$(MAKE) -C contrib/gen_html $@ > $(VOID) @$(RM) zstd$(EXT) zstdmt$(EXT) tmp* @$(RM) -r lz4 @echo Cleaning completed #------------------------------------------------------------------------------ # make install is validated only for Linux, OSX, Hurd and some BSD targets #------------------------------------------------------------------------------ ifneq (,$(filter $(shell uname),Linux Darwin GNU/kFreeBSD GNU FreeBSD DragonFly NetBSD MSYS_NT)) HOST_OS = POSIX CMAKE_PARAMS = -DZSTD_BUILD_CONTRIB:BOOL=ON -DZSTD_BUILD_STATIC:BOOL=ON -DZSTD_BUILD_TESTS:BOOL=ON -DZSTD_ZLIB_SUPPORT:BOOL=ON -DZSTD_LZMA_SUPPORT:BOOL=ON .PHONY: list list: @$(MAKE) -pRrq -f $(lastword $(MAKEFILE_LIST)) : 2>/dev/null | awk -v RS= -F: '/^# File/,/^# Finished Make data base/ {if ($$1 !~ "^[#.]") {print $$1}}' | sort | egrep -v -e '^[^[:alnum:]]' -e '^$@$$' | xargs .PHONY: install clangtest armtest usan asan uasan install: @$(MAKE) -C $(ZSTDDIR) $@ @$(MAKE) -C $(PRGDIR) $@ .PHONY: uninstall uninstall: @$(MAKE) -C $(ZSTDDIR) $@ @$(MAKE) -C $(PRGDIR) $@ .PHONY: travis-install travis-install: $(MAKE) install PREFIX=~/install_test_dir -.PHONY: gppbuild -gppbuild: clean - g++ -v - CC=g++ $(MAKE) -C programs all CFLAGS="-O3 -Wall -Wextra -Wundef -Wshadow -Wcast-align -Werror" - .PHONY: gcc5build gcc5build: clean gcc-5 -v CC=gcc-5 $(MAKE) all MOREFLAGS="-Werror" .PHONY: gcc6build gcc6build: clean gcc-6 -v CC=gcc-6 $(MAKE) all MOREFLAGS="-Werror" .PHONY: gcc7build gcc7build: clean gcc-7 -v CC=gcc-7 $(MAKE) all MOREFLAGS="-Werror" .PHONY: clangbuild clangbuild: clean clang -v CXX=clang++ CC=clang $(MAKE) all MOREFLAGS="-Werror -Wconversion -Wno-sign-conversion -Wdocumentation" m32build: clean gcc -v $(MAKE) all32 armbuild: clean CC=arm-linux-gnueabi-gcc CFLAGS="-Werror" $(MAKE) allzstd aarch64build: clean CC=aarch64-linux-gnu-gcc CFLAGS="-Werror" $(MAKE) allzstd ppcbuild: clean - CC=powerpc-linux-gnu-gcc CLAGS="-m32 -Wno-attributes -Werror" $(MAKE) allzstd + CC=powerpc-linux-gnu-gcc CFLAGS="-m32 -Wno-attributes -Werror" $(MAKE) allzstd ppc64build: clean CC=powerpc-linux-gnu-gcc CFLAGS="-m64 -Werror" $(MAKE) allzstd armfuzz: clean CC=arm-linux-gnueabi-gcc QEMU_SYS=qemu-arm-static MOREFLAGS="-static" FUZZER_FLAGS=--no-big-tests $(MAKE) -C $(TESTDIR) fuzztest aarch64fuzz: clean CC=aarch64-linux-gnu-gcc QEMU_SYS=qemu-aarch64-static MOREFLAGS="-static" FUZZER_FLAGS=--no-big-tests $(MAKE) -C $(TESTDIR) fuzztest ppcfuzz: clean CC=powerpc-linux-gnu-gcc QEMU_SYS=qemu-ppc-static MOREFLAGS="-static" FUZZER_FLAGS=--no-big-tests $(MAKE) -C $(TESTDIR) fuzztest ppc64fuzz: clean CC=powerpc-linux-gnu-gcc QEMU_SYS=qemu-ppc64-static MOREFLAGS="-m64 -static" FUZZER_FLAGS=--no-big-tests $(MAKE) -C $(TESTDIR) fuzztest .PHONY: cxxtest cxxtest: CXXFLAGS += -Wall -Wextra -Wundef -Wshadow -Wcast-align -Werror cxxtest: clean $(MAKE) -C $(PRGDIR) all CC="$(CXX) -Wno-deprecated" CFLAGS="$(CXXFLAGS)" # adding -Wno-deprecated to avoid clang++ warning on dealing with C files directly gcc5test: clean gcc-5 -v $(MAKE) all CC=gcc-5 MOREFLAGS="-Werror" gcc6test: clean gcc-6 -v $(MAKE) all CC=gcc-6 MOREFLAGS="-Werror" clangtest: clean clang -v $(MAKE) all CXX=clang-++ CC=clang MOREFLAGS="-Werror -Wconversion -Wno-sign-conversion -Wdocumentation" armtest: clean $(MAKE) -C $(TESTDIR) datagen # use native, faster $(MAKE) -C $(TESTDIR) test CC=arm-linux-gnueabi-gcc QEMU_SYS=qemu-arm-static ZSTDRTTEST= MOREFLAGS="-Werror -static" FUZZER_FLAGS=--no-big-tests aarch64test: $(MAKE) -C $(TESTDIR) datagen # use native, faster $(MAKE) -C $(TESTDIR) test CC=aarch64-linux-gnu-gcc QEMU_SYS=qemu-aarch64-static ZSTDRTTEST= MOREFLAGS="-Werror -static" FUZZER_FLAGS=--no-big-tests ppctest: clean $(MAKE) -C $(TESTDIR) datagen # use native, faster $(MAKE) -C $(TESTDIR) test CC=powerpc-linux-gnu-gcc QEMU_SYS=qemu-ppc-static ZSTDRTTEST= MOREFLAGS="-Werror -Wno-attributes -static" FUZZER_FLAGS=--no-big-tests ppc64test: clean $(MAKE) -C $(TESTDIR) datagen # use native, faster $(MAKE) -C $(TESTDIR) test CC=powerpc-linux-gnu-gcc QEMU_SYS=qemu-ppc64-static ZSTDRTTEST= MOREFLAGS="-m64 -static" FUZZER_FLAGS=--no-big-tests arm-ppc-compilation: $(MAKE) -C $(PRGDIR) clean zstd CC=arm-linux-gnueabi-gcc QEMU_SYS=qemu-arm-static ZSTDRTTEST= MOREFLAGS="-Werror -static" $(MAKE) -C $(PRGDIR) clean zstd CC=aarch64-linux-gnu-gcc QEMU_SYS=qemu-aarch64-static ZSTDRTTEST= MOREFLAGS="-Werror -static" $(MAKE) -C $(PRGDIR) clean zstd CC=powerpc-linux-gnu-gcc QEMU_SYS=qemu-ppc-static ZSTDRTTEST= MOREFLAGS="-Werror -Wno-attributes -static" $(MAKE) -C $(PRGDIR) clean zstd CC=powerpc-linux-gnu-gcc QEMU_SYS=qemu-ppc64-static ZSTDRTTEST= MOREFLAGS="-m64 -static" regressiontest: $(MAKE) -C $(FUZZDIR) regressiontest uasanregressiontest: $(MAKE) -C $(FUZZDIR) regressiontest CC=clang CXX=clang++ CFLAGS="-O3 -fsanitize=address,undefined" CXXFLAGS="-O3 -fsanitize=address,undefined" msanregressiontest: $(MAKE) -C $(FUZZDIR) regressiontest CC=clang CXX=clang++ CFLAGS="-O3 -fsanitize=memory" CXXFLAGS="-O3 -fsanitize=memory" # run UBsan with -fsanitize-recover=signed-integer-overflow # due to a bug in UBsan when doing pointer subtraction # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63303 usan: clean $(MAKE) test CC=clang MOREFLAGS="-g -fno-sanitize-recover=all -fsanitize-recover=signed-integer-overflow -fsanitize=undefined" asan: clean $(MAKE) test CC=clang MOREFLAGS="-g -fsanitize=address" asan-%: clean LDFLAGS=-fuse-ld=gold MOREFLAGS="-g -fno-sanitize-recover=all -fsanitize=address" $(MAKE) -C $(TESTDIR) $* msan: clean $(MAKE) test CC=clang MOREFLAGS="-g -fsanitize=memory -fno-omit-frame-pointer" HAVE_LZMA=0 # datagen.c fails this test for no obvious reason msan-%: clean LDFLAGS=-fuse-ld=gold MOREFLAGS="-g -fno-sanitize-recover=all -fsanitize=memory -fno-omit-frame-pointer" FUZZER_FLAGS=--no-big-tests $(MAKE) -C $(TESTDIR) HAVE_LZMA=0 $* asan32: clean $(MAKE) -C $(TESTDIR) test32 CC=clang MOREFLAGS="-g -fsanitize=address" uasan: clean $(MAKE) test CC=clang MOREFLAGS="-g -fno-sanitize-recover=all -fsanitize-recover=signed-integer-overflow -fsanitize=address,undefined" uasan-%: clean LDFLAGS=-fuse-ld=gold MOREFLAGS="-g -fno-sanitize-recover=all -fsanitize-recover=signed-integer-overflow -fsanitize=address,undefined" $(MAKE) -C $(TESTDIR) $* tsan-%: clean LDFLAGS=-fuse-ld=gold MOREFLAGS="-g -fno-sanitize-recover=all -fsanitize=thread" $(MAKE) -C $(TESTDIR) $* FUZZER_FLAGS=--no-big-tests apt-install: sudo apt-get -yq --no-install-suggests --no-install-recommends --force-yes install $(APT_PACKAGES) apt-add-repo: sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test sudo apt-get update -y -qq ppcinstall: APT_PACKAGES="qemu-system-ppc qemu-user-static gcc-powerpc-linux-gnu" $(MAKE) apt-install arminstall: APT_PACKAGES="qemu-system-arm qemu-user-static gcc-arm-linux-gnueabi libc6-dev-armel-cross gcc-aarch64-linux-gnu libc6-dev-arm64-cross" $(MAKE) apt-install valgrindinstall: APT_PACKAGES="valgrind" $(MAKE) apt-install libc6install: APT_PACKAGES="libc6-dev-i386 gcc-multilib" $(MAKE) apt-install gcc6install: apt-add-repo APT_PACKAGES="libc6-dev-i386 gcc-multilib gcc-6 gcc-6-multilib" $(MAKE) apt-install gpp6install: apt-add-repo APT_PACKAGES="libc6-dev-i386 g++-multilib gcc-6 g++-6 g++-6-multilib" $(MAKE) apt-install clang38install: APT_PACKAGES="clang-3.8" $(MAKE) apt-install # Ubuntu 14.04 ships a too-old lz4 lz4install: [ -e lz4 ] || git clone https://github.com/lz4/lz4 && sudo $(MAKE) -C lz4 install endif ifneq (,$(filter MSYS%,$(shell uname))) HOST_OS = MSYS CMAKE_PARAMS = -G"MSYS Makefiles" -DZSTD_MULTITHREAD_SUPPORT:BOOL=OFF -DZSTD_BUILD_STATIC:BOOL=ON -DZSTD_BUILD_TESTS:BOOL=ON endif #------------------------------------------------------------------------ # target specific tests #------------------------------------------------------------------------ ifneq (,$(filter $(HOST_OS),MSYS POSIX)) cmakebuild: cmake --version $(RM) -r $(BUILDIR)/cmake/build mkdir $(BUILDIR)/cmake/build cd $(BUILDIR)/cmake/build ; cmake -DCMAKE_INSTALL_PREFIX:PATH=~/install_test_dir $(CMAKE_PARAMS) .. ; $(MAKE) install ; $(MAKE) uninstall c90build: clean $(CC) -v CFLAGS="-std=c90" $(MAKE) allmost # will fail, due to missing support for `long long` gnu90build: clean $(CC) -v CFLAGS="-std=gnu90" $(MAKE) allmost c99build: clean $(CC) -v CFLAGS="-std=c99" $(MAKE) allmost gnu99build: clean $(CC) -v CFLAGS="-std=gnu99" $(MAKE) allmost c11build: clean $(CC) -v CFLAGS="-std=c11" $(MAKE) allmost bmix64build: clean $(CC) -v CFLAGS="-O3 -mbmi -Werror" $(MAKE) -C $(TESTDIR) test bmix32build: clean $(CC) -v CFLAGS="-O3 -mbmi -mx32 -Werror" $(MAKE) -C $(TESTDIR) test bmi32build: clean $(CC) -v CFLAGS="-O3 -mbmi -m32 -Werror" $(MAKE) -C $(TESTDIR) test staticAnalyze: clean $(CC) -v CPPFLAGS=-g scan-build --status-bugs -v $(MAKE) all endif Index: head/sys/contrib/zstd/NEWS =================================================================== --- head/sys/contrib/zstd/NEWS (revision 330893) +++ head/sys/contrib/zstd/NEWS (revision 330894) @@ -1,336 +1,348 @@ +v1.3.3 +perf: faster zstd_opt strategy (levels 17-19) +fix : bug #944 : multithreading with shared ditionary and large data, reported by @gsliepen +cli : fix : content size written in header by default +cli : fix : improved LZ4 format support, by @felixhandte +cli : new : hidden command `-S`, to benchmark multiple files while generating one result per file +api : fix : support large skippable frames, by @terrelln +api : fix : streaming interface was adding a useless 3-bytes null block to small frames +api : change : when setting `pledgedSrcSize`, use `ZSTD_CONTENTSIZE_UNKNOWN` macro value to mean "unknown" +build: fix : compilation under rhel6 and centos6, reported by @pixelb +build: added `check` target + v1.3.2 new : long range mode, using --long command, by Stella Lau (@stellamplau) new : ability to generate and decode magicless frames (#591) changed : maximum nb of threads reduced to 200, to avoid address space exhaustion in 32-bits mode fix : multi-threading compression works with custom allocators fix : ZSTD_sizeof_CStream() was over-evaluating memory usage fix : a rare compression bug when compression generates very large distances and bunch of other conditions (only possible at --ultra -22) fix : 32-bits build can now decode large offsets (levels 21+) cli : added LZ4 frame support by default, by Felix Handte (@felixhandte) cli : improved --list output cli : new : can split input file for dictionary training, using command -B# cli : new : clean operation artefact on Ctrl-C interruption cli : fix : do not change /dev/null permissions when using command -t with root access, reported by @mike155 (#851) cli : fix : write file size in header in multiple-files mode api : added macro ZSTD_COMPRESSBOUND() for static allocation api : experimental : new advanced decompression API api : fix : sizeof_CCtx() used to over-estimate build: fix : no-multithread variant compiles without pool.c dependency, reported by Mitchell Blank Jr (@mitchblank) (#819) build: better compatibility with reproducible builds, by Bernhard M. Wiedemann (@bmwiedemann) (#818) example : added streaming_memory_usage license : changed /examples license to BSD + GPLv2 license : fix a few header files to reflect new license (#825) v1.3.1 New license : BSD + GPLv2 perf: substantially decreased memory usage in Multi-threading mode, thanks to reports by Tino Reichardt (@mcmilk) perf: Multi-threading supports up to 256 threads. Cap at 256 when more are requested (#760) cli : improved and fixed --list command, by @ib (#772) cli : command -vV to list supported formats, by @ib (#771) build : fixed binary variants, reported by @svenha (#788) build : fix Visual compilation for non x86/x64 targets, reported by Greg Slazinski (@GregSlazinski) (#718) API exp : breaking change : ZSTD_getframeHeader() provides more information API exp : breaking change : pinned down values of error codes doc : fixed huffman example, by Ulrich Kunitz (@ulikunitz) new : contrib/adaptive-compression, I/O driven compression strength, by Paul Cruz (@paulcruz74) new : contrib/long_distance_matching, statistics by Stella Lau (@stellamplau) updated : contrib/linux-kernel, by Nick Terrell (@terrelln) v1.3.0 cli : new : `--list` command, by Paul Cruz cli : changed : xz/lzma support enabled by default cli : changed : `-t *` continue processing list after a decompression error API : added : ZSTD_versionString() API : promoted to stable status : ZSTD_getFrameContentSize(), by Sean Purcell API exp : new advanced API : ZSTD_compress_generic(), ZSTD_CCtx_setParameter() API exp : new : API for static or external allocation : ZSTD_initStatic?Ctx() API exp : added : ZSTD_decompressBegin_usingDDict(), requested by Guy Riddle (#700) API exp : clarified memory estimation / measurement functions. API exp : changed : strongest strategy renamed ZSTD_btultra, fastest strategy ZSTD_fast set to 1 tools : decodecorpus can generate random dictionary-compressed samples, by Paul Cruz new : contrib/seekable_format, demo and API, by Sean Purcell changed : contrib/linux-kernel, updated version and license, by Nick Terrell v1.2.0 cli : changed : Multithreading enabled by default (use target zstd-nomt or HAVE_THREAD=0 to disable) cli : new : command -T0 means "detect and use nb of cores", by Sean Purcell cli : new : zstdmt symlink hardwired to `zstd -T0` cli : new : command --threads=# (#671) cli : changed : cover dictionary builder by default, for improved quality, by Nick Terrell cli : new : commands --train-cover and --train-legacy, to select dictionary algorithm and parameters cli : experimental targets `zstd4` and `xzstd4`, with support for lz4 format, by Sean Purcell cli : fix : does not output compressed data on console cli : fix : ignore symbolic links unless --force specified, API : breaking change : ZSTD_createCDict_advanced(), only use compressionParameters as argument API : added : prototypes ZSTD_*_usingCDict_advanced(), for direct control over frameParameters. API : improved: ZSTDMT_compressCCtx() reduced memory usage API : fix : ZSTDMT_compressCCtx() now provides srcSize in header (#634) API : fix : src size stored in frame header is controlled at end of frame API : fix : enforced consistent rules for pledgedSrcSize==0 (#641) API : fix : error code "GENERIC" replaced by "dstSizeTooSmall" when appropriate build: improved cmake script, by @Majlen build: enabled Multi-threading support for *BSD, by Baptiste Daroussin tools: updated Paramgrill. Command -O# provides best parameters for sample and speed target. new : contrib/linux-kernel version, by Nick Terrell v1.1.4 cli : new : can compress in *.gz format, using --format=gzip command, by Przemyslaw Skibinski cli : new : advanced benchmark command --priority=rt cli : fix : write on sparse-enabled file systems in 32-bits mode, by @ds77 cli : fix : --rm remains silent when input is stdin cli : experimental : xzstd, with support for xz/lzma decoding, by Przemyslaw Skibinski speed : improved decompression speed in streaming mode for single shot scenarios (+5%) memory: DDict (decompression dictionary) memory usage down from 150 KB to 20 KB arch: 32-bits variant able to generate and decode very long matches (>32 MB), by Sean Purcell API : new : ZSTD_findFrameCompressedSize(), ZSTD_getFrameContentSize(), ZSTD_findDecompressedSize() API : changed : dropped support of legacy versions <= v0.3 (can be changed by modifying ZSTD_LEGACY_SUPPORT value) build : new: meson build system in contrib/meson, by Dima Krasner build : improved cmake script, by @Majlen build : added -Wformat-security flag, as recommended by Padraig Brady doc : new : educational decoder, by Sean Purcell v1.1.3 cli : zstd can decompress .gz files (can be disabled with `make zstd-nogz` or `make HAVE_ZLIB=0`) cli : new : experimental target `make zstdmt`, with multi-threading support cli : new : improved dictionary builder "cover" (experimental), by Nick Terrell, based on prior work by Giuseppe Ottaviano. cli : new : advanced commands for detailed parameters, by Przemyslaw Skibinski cli : fix zstdless on Mac OS-X, by Andrew Janke cli : fix #232 "compress non-files" dictBuilder : improved dictionary generation quality, thanks to Nick Terrell API : new : lib/compress/ZSTDMT_compress.h multithreading API (experimental) API : new : ZSTD_create?Dict_byReference(), requested by Bartosz Taudul API : new : ZDICT_finalizeDictionary() API : fix : ZSTD_initCStream_usingCDict() properly writes dictID into frame header, by Gregory Szorc (#511) API : fix : all symbols properly exposed in libzstd, by Nick Terrell build : support for Solaris target, by Przemyslaw Skibinski doc : clarified specification, by Sean Purcell v1.1.2 API : streaming : decompression : changed : automatic implicit reset when chain-decoding new frames without init API : experimental : added : dictID retrieval functions, and ZSTD_initCStream_srcSize() API : zbuff : changed : prototypes now generate deprecation warnings lib : improved : faster decompression speed at ultra compression settings and 32-bits mode lib : changed : only public ZSTD_ symbols are now exposed lib : changed : reduced usage of stack memory lib : fixed : several corner case bugs, by Nick Terrell cli : new : gzstd, experimental version able to decode .gz files, by Przemyslaw Skibinski cli : new : preserve file attributes cli : new : added zstdless and zstdgrep tools cli : fixed : status displays total amount decoded, even for file consisting of multiple frames (like pzstd) cli : fixed : zstdcat zlib_wrapper : added support for gz* functions, by Przemyslaw Skibinski install : better compatibility with FreeBSD, by Dimitry Andric source tree : changed : zbuff source files moved to lib/deprecated v1.1.1 New : command -M#, --memory=, --memlimit=, --memlimit-decompress= to limit allowed memory consumption New : doc/zstd_manual.html, by Przemyslaw Skibinski Improved : slightly better compression ratio at --ultra levels (>= 20) Improved : better memory usage when using streaming compression API, thanks to @Rogier-5 report Added : API : ZSTD_initCStream_usingCDict(), ZSTD_initDStream_usingDDict() (experimental section) Added : example/multiple_streaming_compression.c Changed : zstd_errors.h is now installed within /include (and replaces errors_public.h) Updated man page Fixed : zstd-small, zstd-compress and zstd-decompress compilation targets v1.1.0 New : contrib/pzstd, parallel version of zstd, by Nick Terrell added : NetBSD install target (#338) Improved : speed for batches of small files Improved : speed of zlib wrapper, by Przemyslaw Skibinski Changed : libzstd on Windows supports legacy formats, by Christophe Chevalier Fixed : CLI -d output to stdout by default when input is stdin (#322) Fixed : CLI correctly detects console on Mac OS-X Fixed : CLI supports recursive mode `-r` on Mac OS-X Fixed : Legacy decoders use unified error codes, reported by benrg (#341), fixed by Przemyslaw Skibinski Fixed : compatibility with OpenBSD, reported by Juan Francisco Cantero Hurtado (#319) Fixed : compatibility with Hurd, by Przemyslaw Skibinski (#365) Fixed : zstd-pgo, reported by octoploid (#329) v1.0.0 Change Licensing, all project is now BSD, Copyright Facebook Small decompression speed improvement API : Streaming API supports legacy format API : ZDICT_getDictID(), ZSTD_sizeof_{CCtx, DCtx, CStream, DStream}(), ZSTD_setDStreamParamter() CLI supports legacy formats v0.4+ Fixed : compression fails on certain huge files, reported by Jesse McGrew Enhanced documentation, by Przemyslaw Skibinski v0.8.1 New streaming API Changed : --ultra now enables levels beyond 19 Changed : -i# now selects benchmark time in second Fixed : ZSTD_compress* can now compress > 4 GB in a single pass, reported by Nick Terrell Fixed : speed regression on specific patterns (#272) Fixed : support for Z_SYNC_FLUSH, by Dmitry Krot (#291) Fixed : ICC compilation, by Przemyslaw Skibinski v0.8.0 Improved : better speed on clang and gcc -O2, thanks to Eric Biggers New : Build on FreeBSD and DragonFly, thanks to JrMarino Changed : modified API : ZSTD_compressEnd() Fixed : legacy mode with ZSTD_HEAPMODE=0, by Christopher Bergqvist Fixed : premature end of frame when zero-sized raw block, reported by Eric Biggers Fixed : large dictionaries (> 384 KB), reported by Ilona Papava Fixed : checksum correctly checked in single-pass mode Fixed : combined --test amd --rm, reported by Andreas M. Nilsson Modified : minor compression level adaptations Updated : compression format specification to v0.2.0 changed : zstd.h moved to /lib directory v0.7.5 Transition version, supporting decoding of v0.8.x v0.7.4 Added : homebrew for Mac, by Daniel Cade Added : more examples Fixed : segfault when using small dictionaries, reported by Felix Handte Modified : default compression level for CLI is now 3 Updated : specification, to v0.1.1 v0.7.3 New : compression format specification New : `--` separator, stating that all following arguments are file names. Suggested by Chip Turner. New : `ZSTD_getDecompressedSize()` New : OpenBSD target, by Juan Francisco Cantero Hurtado New : `examples` directory fixed : dictBuilder using HC levels, reported by Bartosz Taudul fixed : legacy support from ZSTD_decompress_usingDDict(), reported by Felix Handte fixed : multi-blocks decoding with intermediate uncompressed blocks, reported by Greg Slazinski modified : removed "mem.h" and "error_public.h" dependencies from "zstd.h" (experimental section) modified : legacy functions no longer need magic number v0.7.2 fixed : ZSTD_decompressBlock() using multiple consecutive blocks. Reported by Greg Slazinski. fixed : potential segfault on very large files (many gigabytes). Reported by Chip Turner. fixed : CLI displays system error message when destination file cannot be created (#231). Reported by Chip Turner. v0.7.1 fixed : ZBUFF_compressEnd() called multiple times with too small `dst` buffer, reported by Christophe Chevalier fixed : dictBuilder fails if first sample is too small, reported by Руслан Ковалёв fixed : corruption issue, reported by cj modified : checksum enabled by default in command line mode v0.7.0 New : Support for directory compression, using `-r`, thanks to Przemyslaw Skibinski New : Command `--rm`, to remove source file after successful de/compression New : Visual build scripts, by Christophe Chevalier New : Support for Sparse File-systems (do not use space for zero-filled sectors) New : Frame checksum support New : Support pass-through mode (when using `-df`) API : more efficient Dictionary API : `ZSTD_compress_usingCDict()`, `ZSTD_decompress_usingDDict()` API : create dictionary files from custom content, by Giuseppe Ottaviano API : support for custom malloc/free functions New : controllable Dictionary ID New : Support for skippable frames v0.6.1 New : zlib wrapper API, thanks to Przemyslaw Skibinski New : Ability to compile compressor / decompressor separately Changed : new lib directory structure Fixed : Legacy codec v0.5 compatible with dictionary decompression Fixed : Decoder corruption error (#173) Fixed : null-string roundtrip (#176) New : benchmark mode can select directory as input Experimental : midipix support, VMS support v0.6.0 Stronger high compression modes, thanks to Przemyslaw Skibinski API : ZSTD_getFrameParams() provides size of decompressed content New : highest compression modes require `--ultra` command to fully unleash their capacity Fixed : zstd cli return error code > 0 and removes dst file artifact when decompression fails, thanks to Chip Turner v0.5.1 New : Optimal parsing => Very high compression modes, thanks to Przemyslaw Skibinski Changed : Dictionary builder integrated into libzstd and zstd cli Changed (!) : zstd cli now uses "multiple input files" as default mode. See `zstd -h`. Fix : high compression modes for big-endian platforms New : zstd cli : `-t` | `--test` command v0.5.0 New : dictionary builder utility Changed : streaming & dictionary API Improved : better compression of small data v0.4.7 Improved : small compression speed improvement in HC mode Changed : `zstd_decompress.c` has ZSTD_LEGACY_SUPPORT to 0 by default fix : bt search bug v0.4.6 fix : fast compression mode on Windows New : cmake configuration file, thanks to Artyom Dymchenko Improved : high compression mode on repetitive data New : block-level API New : ZSTD_duplicateCCtx() v0.4.5 new : -m/--multiple : compress/decompress multiple files v0.4.4 Fixed : high compression modes for Windows 32 bits new : external dictionary API extended to buffered mode and accessible through command line new : windows DLL project, thanks to Christophe Chevalier v0.4.3 : new : external dictionary API new : zstd-frugal v0.4.2 : Generic minor improvements for small blocks Fixed : big-endian compatibility, by Peter Harris (#85) v0.4.1 Fixed : ZSTD_LEGACY_SUPPORT=0 build mode (reported by Luben) removed `zstd.c` v0.4.0 Command line utility compatible with high compression levels Removed zstdhc => merged into zstd Added : ZBUFF API (see zstd_buffered.h) Rolling buffer support v0.3.6 small blocks params v0.3.5 minor generic compression improvements v0.3.4 Faster fast cLevels v0.3.3 Small compression ratio improvement v0.3.2 Fixed Visual Studio v0.3.1 : Small compression ratio improvement v0.3 HC mode : compression levels 2-26 v0.2.2 Fix : Visual Studio 2013 & 2015 release compilation, by Christophe Chevalier v0.2.1 Fix : Read errors, advanced fuzzer tests, by Hanno Böck v0.2.0 **Breaking format change** Faster decompression speed Can still decode v0.1 format v0.1.3 fix uninitialization warning, reported by Evan Nemerson v0.1.2 frame concatenation support v0.1.1 fix compression bug detects write-flush errors v0.1.0 first release Index: head/sys/contrib/zstd/README.md =================================================================== --- head/sys/contrib/zstd/README.md (revision 330893) +++ head/sys/contrib/zstd/README.md (revision 330894) @@ -1,153 +1,150 @@ - __Zstandard__, or `zstd` as short version, is a fast lossless compression algorithm, - targeting real-time compression scenarios at zlib-level and better compression ratios. +

Zstandard

-It is provided as an open-source BSD-licensed **C** library, -and a command line utility producing and decoding `.zst` and `.gz` files. -For other programming languages, -you can consult a list of known ports on [Zstandard homepage](http://www.zstd.net/#other-languages). +__Zstandard__, or `zstd` as short version, is a fast lossless compression algorithm, +targeting real-time compression scenarios at zlib-level and better compression ratios. +It's backed by a very fast entropy stage, provided by [Huff0 and FSE library](https://github.com/Cyan4973/FiniteStateEntropy). -| dev branch status | -|-------------------| -| [![Build Status][travisDevBadge]][travisLink] [![Build status][AppveyorDevBadge]][AppveyorLink] [![Build status][CircleDevBadge]][CircleLink] +The project is provided as an open-source BSD-licensed **C** library, +and a command line utility producing and decoding `.zst`, `.gz`, `.xz` and `.lz4` files. +Should your project require another programming language, +a list of known ports and bindings is provided on [Zstandard homepage](http://www.zstd.net/#other-languages). +Development branch status : [![Build Status][travisDevBadge]][travisLink] [![Build status][AppveyorDevBadge]][AppveyorLink] [![Build status][CircleDevBadge]][CircleLink] + [travisDevBadge]: https://travis-ci.org/facebook/zstd.svg?branch=dev "Continuous Integration test suite" [travisLink]: https://travis-ci.org/facebook/zstd [AppveyorDevBadge]: https://ci.appveyor.com/api/projects/status/xt38wbdxjk5mrbem/branch/dev?svg=true "Windows test suite" [AppveyorLink]: https://ci.appveyor.com/project/YannCollet/zstd-p0yf0 [CircleDevBadge]: https://circleci.com/gh/facebook/zstd/tree/dev.svg?style=shield "Short test suite" [CircleLink]: https://circleci.com/gh/facebook/zstd +### Benchmarks -As a reference, several fast compression algorithms were tested and compared +For reference, several fast compression algorithms were tested and compared on a server running Linux Debian (`Linux version 4.8.0-1-amd64`), with a Core i7-6700K CPU @ 4.0GHz, using [lzbench], an open-source in-memory benchmark by @inikep compiled with GCC 6.3.0, on the [Silesia compression corpus]. [lzbench]: https://github.com/inikep/lzbench [Silesia compression corpus]: http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia | Compressor name | Ratio | Compression| Decompress.| | --------------- | ------| -----------| ---------- | | **zstd 1.1.3 -1** | 2.877 | 430 MB/s | 1110 MB/s | | zlib 1.2.8 -1 | 2.743 | 110 MB/s | 400 MB/s | | brotli 0.5.2 -0 | 2.708 | 400 MB/s | 430 MB/s | | quicklz 1.5.0 -1 | 2.238 | 550 MB/s | 710 MB/s | | lzo1x 2.09 -1 | 2.108 | 650 MB/s | 830 MB/s | | lz4 1.7.5 | 2.101 | 720 MB/s | 3600 MB/s | | snappy 1.1.3 | 2.091 | 500 MB/s | 1650 MB/s | | lzf 3.6 -1 | 2.077 | 400 MB/s | 860 MB/s | [zlib]:http://www.zlib.net/ [LZ4]: http://www.lz4.org/ Zstd can also offer stronger compression ratios at the cost of compression speed. -Speed vs Compression trade-off is configurable by small increments. Decompression speed is preserved and remains roughly the same at all settings, a property shared by most LZ compression algorithms, such as [zlib] or lzma. +Speed vs Compression trade-off is configurable by small increments. +Decompression speed is preserved and remains roughly the same at all settings, +a property shared by most LZ compression algorithms, such as [zlib] or lzma. The following tests were run on a server running Linux Debian (`Linux version 4.8.0-1-amd64`) with a Core i7-6700K CPU @ 4.0GHz, using [lzbench], an open-source in-memory benchmark by @inikep compiled with GCC 6.3.0, on the [Silesia compression corpus]. Compression Speed vs Ratio | Decompression Speed ---------------------------|-------------------- ![Compression Speed vs Ratio](doc/images/Cspeed4.png "Compression Speed vs Ratio") | ![Decompression Speed](doc/images/Dspeed4.png "Decompression Speed") -Several algorithms can produce higher compression ratios, but at slower speeds, falling outside of the graph. -For a larger picture including very slow modes, [click on this link](doc/images/DCspeed5.png) . +A few other algorithms can produce higher compression ratios at slower speeds, falling outside of the graph. +For a larger picture including slow modes, [click on this link](doc/images/DCspeed5.png). ### The case for Small Data compression Previous charts provide results applicable to typical file and stream scenarios (several MB). Small data comes with different perspectives. The smaller the amount of data to compress, the more difficult it is to compress. This problem is common to all compression algorithms, and reason is, compression algorithms learn from past data how to compress future data. But at the beginning of a new data set, there is no "past" to build upon. To solve this situation, Zstd offers a __training mode__, which can be used to tune the algorithm for a selected type of data. Training Zstandard is achieved by providing it with a few samples (one file per sample). The result of this training is stored in a file called "dictionary", which must be loaded before compression and decompression. Using this dictionary, the compression ratio achievable on small data improves dramatically. The following example uses the `github-users` [sample set](https://github.com/facebook/zstd/releases/tag/v1.1.3), created from [github public API](https://developer.github.com/v3/users/#get-all-users). It consists of roughly 10K records weighing about 1KB each. Compression Ratio | Compression Speed | Decompression Speed ------------------|-------------------|-------------------- ![Compression Ratio](doc/images/dict-cr.png "Compression Ratio") | ![Compression Speed](doc/images/dict-cs.png "Compression Speed") | ![Decompression Speed](doc/images/dict-ds.png "Decompression Speed") These compression gains are achieved while simultaneously providing _faster_ compression and decompression speeds. Training works if there is some correlation in a family of small data samples. The more data-specific a dictionary is, the more efficient it is (there is no _universal dictionary_). Hence, deploying one dictionary per type of data will provide the greatest benefits. Dictionary gains are mostly effective in the first few KB. Then, the compression algorithm will gradually use previously decoded content to better compress the rest of the file. -#### Dictionary compression How To : +#### Dictionary compression How To: 1) Create the dictionary `zstd --train FullPathToTrainingSet/* -o dictionaryName` 2) Compress with dictionary `zstd -D dictionaryName FILE` 3) Decompress with dictionary `zstd -D dictionaryName --decompress FILE.zst` -### Build +### Build instructions -Once you have the repository cloned, there are multiple ways provided to build Zstandard. - #### Makefile -If your system is compatible with a standard `make` (or `gmake`) binary generator, -you can simply run it at the root directory. -It will generate `zstd` within root directory. +If your system is compatible with standard `make` (or `gmake`), +invoking `make` in root directory will generate `zstd` cli in root directory. -Other available options include : -- `make install` : create and install zstd binary, library and man page -- `make test` : create and run `zstd` and test tools on local platform +Other available options include: +- `make install` : create and install zstd cli, library and man pages +- `make check` : create and run `zstd`, tests its behavior on local platform #### cmake A `cmake` project generator is provided within `build/cmake`. It can generate Makefiles or other build scripts to create `zstd` binary, and `libzstd` dynamic and static libraries. #### Meson A Meson project is provided within `contrib/meson`. #### Visual Studio (Windows) -Going into `build` directory, you will find additional possibilities : -- Projects for Visual Studio 2005, 2008 and 2010 - + VS2010 project is compatible with VS2012, VS2013 and VS2015 +Going into `build` directory, you will find additional possibilities: +- Projects for Visual Studio 2005, 2008 and 2010. + + VS2010 project is compatible with VS2012, VS2013 and VS2015. - Automated build scripts for Visual compiler by @KrzysFR , in `build/VS_scripts`, which will build `zstd` cli and `libzstd` library without any need to open Visual Studio solution. ### Status Zstandard is currently deployed within Facebook. It is used continuously to compress large amounts of data in multiple formats and use cases. Zstandard is considered safe for production environments. ### License Zstandard is dual-licensed under [BSD](LICENSE) and [GPLv2](COPYING). ### Contributing -The "dev" branch is the one where all contributions will be merged before reaching "master". -If you plan to propose a patch, please commit into the "dev" branch or its own feature branch. +The "dev" branch is the one where all contributions are merged before reaching "master". +If you plan to propose a patch, please commit into the "dev" branch, or its own feature branch. Direct commit to "master" are not permitted. For more information, please read [CONTRIBUTING](CONTRIBUTING.md). - -### Miscellaneous - -Zstd entropy stage is provided by [Huff0 and FSE, from Finite State Entropy library](https://github.com/Cyan4973/FiniteStateEntropy). Index: head/sys/contrib/zstd/circle.yml =================================================================== --- head/sys/contrib/zstd/circle.yml (revision 330893) +++ head/sys/contrib/zstd/circle.yml (revision 330894) @@ -1,80 +1,63 @@ dependencies: override: - sudo dpkg --add-architecture i386 - sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test; sudo apt-get -y -qq update - sudo apt-get -y install gcc-powerpc-linux-gnu gcc-arm-linux-gnueabi libc6-dev-armel-cross gcc-aarch64-linux-gnu libc6-dev-arm64-cross - - sudo apt-get -y install libstdc++-7-dev clang gcc g++ gcc-5 gcc-6 gcc-7 zlib1g-dev liblzma-dev - - sudo apt-get -y install linux-libc-dev:i386 libc6-dev-i386 test: override: - ? | - if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then cc -v; make all && make clean && make -C lib libzstd-nomt && make clean; fi && + if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then cc -v; CFLAGS="-O0 -Werror" make all && make clean; fi && if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make gnu90build && make clean; fi : parallel: true - ? | if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make c99build && make clean; fi && if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make gnu99build && make clean; fi : parallel: true - ? | if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make c11build && make clean; fi && - if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make cmakebuild && make clean; fi + if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make ppc64build && make clean; fi : parallel: true - ? | - if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make gppbuild && make clean; fi && - if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make gcc5build && make clean; fi - : - parallel: true - - ? | - if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make gcc6build && make clean; fi && - if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make clangbuild && make clean; fi - : - parallel: true - - ? | - if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make m32build && make clean; fi && - if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make armbuild && make clean; fi - : - parallel: true - - ? | if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make aarch64build && make clean; fi && if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make ppcbuild && make clean; fi : parallel: true - ? | - if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make ppc64build && make clean; fi && - if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make gcc7build && make clean; fi + if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make -j regressiontest && make clean; fi && + if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make armbuild && make clean; fi : parallel: true - ? | if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make shortest && make clean; fi && if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make -C tests test-legacy test-longmatch test-symbols && make clean; fi : parallel: true - ? | - if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make -j regressiontest && make clean; fi && - if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then true; fi # Could add another test here + if [[ "$CIRCLE_NODE_INDEX" == "0" ]] ; then make cxxtest && make clean; fi && + if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make -C lib libzstd-nomt && make clean; fi : parallel: true post: - echo Circle CI tests finished # Longer tests #- make -C tests test-zstd-nolegacy && make clean #- pyenv global 3.4.4; make -C tests versionsTest && make clean #- make zlibwrapper && make clean #- gcc -v; make -C tests test32 MOREFLAGS="-I/usr/include/x86_64-linux-gnu" && make clean #- make uasan && make clean #- make asan32 && make clean #- make -C tests test32 CC=clang MOREFLAGS="-g -fsanitize=address -I/usr/include/x86_64-linux-gnu" # Valgrind tests #- CFLAGS="-O1 -g" make -C zlibWrapper valgrindTest && make clean #- make -C tests valgrindTest && make clean # ARM, AArch64, PowerPC, PowerPC64 tests #- make ppctest && make clean #- make ppc64test && make clean #- make armtest && make clean #- make aarch64test && make clean Index: head/sys/contrib/zstd/contrib/meson/meson.build =================================================================== --- head/sys/contrib/zstd/contrib/meson/meson.build (revision 330893) +++ head/sys/contrib/zstd/contrib/meson/meson.build (revision 330894) @@ -1,79 +1,116 @@ project('zstd', 'c', license: 'BSD') libm = meson.get_compiler('c').find_library('m', required: true) -lib_dir = join_paths(meson.source_root(), '..', '..', 'lib') +lib_dir = join_paths('..', '..', 'lib') common_dir = join_paths(lib_dir, 'common') compress_dir = join_paths(lib_dir, 'compress') decompress_dir = join_paths(lib_dir, 'decompress') dictbuilder_dir = join_paths(lib_dir, 'dictBuilder') deprecated_dir = join_paths(lib_dir, 'deprecated') -libzstd_srcs = [join_paths(common_dir, 'entropy_common.c'), join_paths(common_dir, 'fse_decompress.c'), join_paths(common_dir, 'threading.c'), join_paths(common_dir, 'pool.c'), join_paths(common_dir, 'zstd_common.c'), join_paths(common_dir, 'error_private.c'), join_paths(common_dir, 'xxhash.c'), join_paths(compress_dir, 'fse_compress.c'), join_paths(compress_dir, 'huf_compress.c'), join_paths(compress_dir, 'zstd_compress.c'), join_paths(compress_dir, 'zstdmt_compress.c'), join_paths(decompress_dir, 'huf_decompress.c'), join_paths(decompress_dir, 'zstd_decompress.c'), join_paths(dictbuilder_dir, 'cover.c'), join_paths(dictbuilder_dir, 'divsufsort.c'), join_paths(dictbuilder_dir, 'zdict.c'), join_paths(deprecated_dir, 'zbuff_common.c'), join_paths(deprecated_dir, 'zbuff_compress.c'), join_paths(deprecated_dir, 'zbuff_decompress.c')] +libzstd_srcs = [ + join_paths(common_dir, 'entropy_common.c'), + join_paths(common_dir, 'fse_decompress.c'), + join_paths(common_dir, 'threading.c'), + join_paths(common_dir, 'pool.c'), + join_paths(common_dir, 'zstd_common.c'), + join_paths(common_dir, 'error_private.c'), + join_paths(common_dir, 'xxhash.c'), + join_paths(compress_dir, 'fse_compress.c'), + join_paths(compress_dir, 'huf_compress.c'), + join_paths(compress_dir, 'zstd_compress.c'), + join_paths(compress_dir, 'zstd_fast.c'), + join_paths(compress_dir, 'zstd_double_fast.c'), + join_paths(compress_dir, 'zstd_lazy.c'), + join_paths(compress_dir, 'zstd_opt.c'), + join_paths(compress_dir, 'zstd_ldm.c'), + join_paths(compress_dir, 'zstdmt_compress.c'), + join_paths(decompress_dir, 'huf_decompress.c'), + join_paths(decompress_dir, 'zstd_decompress.c'), + join_paths(dictbuilder_dir, 'cover.c'), + join_paths(dictbuilder_dir, 'divsufsort.c'), + join_paths(dictbuilder_dir, 'zdict.c'), + join_paths(deprecated_dir, 'zbuff_common.c'), + join_paths(deprecated_dir, 'zbuff_compress.c'), + join_paths(deprecated_dir, 'zbuff_decompress.c') +] libzstd_includes = [include_directories(common_dir, dictbuilder_dir, compress_dir, lib_dir)] if get_option('legacy_support') message('Enabling legacy support') libzstd_cflags = ['-DZSTD_LEGACY_SUPPORT=4'] legacy_dir = join_paths(lib_dir, 'legacy') libzstd_includes += [include_directories(legacy_dir)] - libzstd_srcs += [join_paths(legacy_dir, 'zstd_v01.c'), join_paths(legacy_dir, 'zstd_v02.c'), join_paths(legacy_dir, 'zstd_v03.c'), join_paths(legacy_dir, 'zstd_v04.c'), join_paths(legacy_dir, 'zstd_v05.c'), join_paths(legacy_dir, 'zstd_v06.c'), join_paths(legacy_dir, 'zstd_v07.c')] + libzstd_srcs += [ + join_paths(legacy_dir, 'zstd_v01.c'), + join_paths(legacy_dir, 'zstd_v02.c'), + join_paths(legacy_dir, 'zstd_v03.c'), + join_paths(legacy_dir, 'zstd_v04.c'), + join_paths(legacy_dir, 'zstd_v05.c'), + join_paths(legacy_dir, 'zstd_v06.c'), + join_paths(legacy_dir, 'zstd_v07.c') + ] else libzstd_cflags = [] endif if get_option('multithread') message('Enabling multi-threading support') add_global_arguments('-DZSTD_MULTITHREAD', language: 'c') libzstd_deps = [dependency('threads')] else libzstd_deps = [] endif libzstd = library('zstd', libzstd_srcs, include_directories: libzstd_includes, c_args: libzstd_cflags, dependencies: libzstd_deps, install: true) -programs_dir = join_paths(meson.source_root(), '..', '..', 'programs') +programs_dir = join_paths('..', '..', 'programs') zstd = executable('zstd', - join_paths(programs_dir, 'bench.c'), join_paths(programs_dir, 'datagen.c'), join_paths(programs_dir, 'dibio.c'), join_paths(programs_dir, 'fileio.c'), join_paths(programs_dir, 'zstdcli.c'), + join_paths(programs_dir, 'bench.c'), + join_paths(programs_dir, 'datagen.c'), + join_paths(programs_dir, 'dibio.c'), + join_paths(programs_dir, 'fileio.c'), + join_paths(programs_dir, 'zstdcli.c'), include_directories: libzstd_includes, c_args: ['-DZSTD_NODICT', '-DZSTD_NOBENCH'], link_with: libzstd, install: true) -tests_dir = join_paths(meson.source_root(), '..', '..', 'tests') +tests_dir = join_paths('..', '..', 'tests') datagen_c = join_paths(programs_dir, 'datagen.c') test_includes = libzstd_includes + [include_directories(programs_dir)] fullbench = executable('fullbench', datagen_c, join_paths(tests_dir, 'fullbench.c'), include_directories: test_includes, link_with: libzstd) test('fullbench', fullbench) fuzzer = executable('fuzzer', datagen_c, join_paths(tests_dir, 'fuzzer.c'), include_directories: test_includes, link_with: libzstd) test('fuzzer', fuzzer) if target_machine.system() != 'windows' paramgrill = executable('paramgrill', datagen_c, join_paths(tests_dir, 'paramgrill.c'), include_directories: test_includes, link_with: libzstd, dependencies: libm) test('paramgrill', paramgrill) datagen = executable('datagen', datagen_c, join_paths(tests_dir, 'datagencli.c'), include_directories: test_includes, link_with: libzstd) endif Index: head/sys/contrib/zstd/doc/images/zstd_logo86.png =================================================================== Cannot display: file marked as a binary type. svn:mime-type = image/png Property changes on: head/sys/contrib/zstd/doc/images/zstd_logo86.png ___________________________________________________________________ Added: svn:mime-type ## -0,0 +1 ## +image/png \ No newline at end of property Index: head/sys/contrib/zstd/doc/zstd_compression_format.md =================================================================== --- head/sys/contrib/zstd/doc/zstd_compression_format.md (revision 330893) +++ head/sys/contrib/zstd/doc/zstd_compression_format.md (revision 330894) @@ -1,1535 +1,1535 @@ Zstandard Compression Format ============================ ### Notices Copyright (c) 2016-present Yann Collet, Facebook, Inc. Permission is granted to copy and distribute this document for any purpose and without charge, including translations into other languages and incorporation into compilations, provided that the copyright notice and this notice are preserved, and that any substantive changes or deletions from the original are clearly marked. Distribution of this document is unlimited. ### Version 0.2.6 (19/08/17) Introduction ------------ The purpose of this document is to define a lossless compressed data format, that is independent of CPU type, operating system, file system and character set, suitable for file compression, pipe and streaming compression, using the [Zstandard algorithm](http://www.zstandard.org). The data can be produced or consumed, even for an arbitrarily long sequentially presented input data stream, using only an a priori bounded amount of intermediate storage, and hence can be used in data communications. The format uses the Zstandard compression method, and optional [xxHash-64 checksum method](http://www.xxhash.org), for detection of data corruption. The data format defined by this specification does not attempt to allow random access to compressed data. This specification is intended for use by implementers of software to compress data into Zstandard format and/or decompress data from Zstandard format. The text of the specification assumes a basic background in programming at the level of bits and other primitive data representations. Unless otherwise indicated below, a compliant compressor must produce data sets that conform to the specifications presented here. It doesn’t need to support all options though. A compliant decompressor must be able to decompress at least one working set of parameters that conforms to the specifications presented here. It may also ignore informative fields, such as checksum. Whenever it does not support a parameter defined in the compressed stream, it must produce a non-ambiguous error code and associated error message explaining which parameter is unsupported. ### Overall conventions In this document: - square brackets i.e. `[` and `]` are used to indicate optional fields or parameters. - the naming convention for identifiers is `Mixed_Case_With_Underscores` ### Definitions Content compressed by Zstandard is transformed into a Zstandard __frame__. Multiple frames can be appended into a single file or stream. A frame is completely independent, has a defined beginning and end, and a set of parameters which tells the decoder how to decompress it. A frame encapsulates one or multiple __blocks__. Each block can be compressed or not, and has a guaranteed maximum content size, which depends on frame parameters. Unlike frames, each block depends on previous blocks for proper decoding. However, each block can be decompressed without waiting for its successor, allowing streaming operations. Overview --------- - [Frames](#frames) - [Zstandard frames](#zstandard-frames) - [Blocks](#blocks) - [Literals Section](#literals-section) - [Sequences Section](#sequences-section) - [Sequence Execution](#sequence-execution) - [Skippable frames](#skippable-frames) - [Entropy Encoding](#entropy-encoding) - [FSE](#fse) - [Huffman Coding](#huffman-coding) - [Dictionary Format](#dictionary-format) Frames ------ -Zstandard compressed data is made of up one or more __frames__. +Zstandard compressed data is made of one or more __frames__. Each frame is independent and can be decompressed indepedently of other frames. The decompressed content of multiple concatenated frames is the concatenation of -each frames decompressed content. +each frame decompressed content. There are two frame formats defined by Zstandard: Zstandard frames and Skippable frames. Zstandard frames contain compressed data, while skippable frames contain no data and can be used for metadata. ## Zstandard frames The structure of a single Zstandard frame is following: | `Magic_Number` | `Frame_Header` |`Data_Block`| [More data blocks] | [`Content_Checksum`] | |:--------------:|:--------------:|:----------:| ------------------ |:--------------------:| | 4 bytes | 2-14 bytes | n bytes | | 0-4 bytes | __`Magic_Number`__ 4 Bytes, __little-endian__ format. Value : 0xFD2FB528 __`Frame_Header`__ 2 to 14 Bytes, detailed in [`Frame_Header`](#frame_header). __`Data_Block`__ Detailed in [`Blocks`](#blocks). That’s where compressed data is stored. __`Content_Checksum`__ An optional 32-bit checksum, only present if `Content_Checksum_flag` is set. The content checksum is the result of [xxh64() hash function](http://www.xxhash.org) digesting the original (decoded) data as input, and a seed of zero. The low 4 bytes of the checksum are stored in __little-endian__ format. ### `Frame_Header` The `Frame_Header` has a variable size, with a minimum of 2 bytes, and up to 14 bytes depending on optional parameters. The structure of `Frame_Header` is following: | `Frame_Header_Descriptor` | [`Window_Descriptor`] | [`Dictionary_ID`] | [`Frame_Content_Size`] | | ------------------------- | --------------------- | ----------------- | ---------------------- | | 1 byte | 0-1 byte | 0-4 bytes | 0-8 bytes | #### `Frame_Header_Descriptor` The first header's byte is called the `Frame_Header_Descriptor`. It describes which other fields are present. Decoding this byte is enough to tell the size of `Frame_Header`. | Bit number | Field name | | ---------- | ---------- | | 7-6 | `Frame_Content_Size_flag` | | 5 | `Single_Segment_flag` | | 4 | `Unused_bit` | | 3 | `Reserved_bit` | | 2 | `Content_Checksum_flag` | | 1-0 | `Dictionary_ID_flag` | In this table, bit 7 is the highest bit, while bit 0 is the lowest one. __`Frame_Content_Size_flag`__ This is a 2-bits flag (`= Frame_Header_Descriptor >> 6`), specifying if `Frame_Content_Size` (the decompressed data size) is provided within the header. `Flag_Value` provides `FCS_Field_Size`, which is the number of bytes used by `Frame_Content_Size` according to the following table: | `Flag_Value` | 0 | 1 | 2 | 3 | | -------------- | ------ | --- | --- | --- | |`FCS_Field_Size`| 0 or 1 | 2 | 4 | 8 | When `Flag_Value` is `0`, `FCS_Field_Size` depends on `Single_Segment_flag` : if `Single_Segment_flag` is set, `Field_Size` is 1. Otherwise, `Field_Size` is 0 : `Frame_Content_Size` is not provided. __`Single_Segment_flag`__ If this flag is set, data must be regenerated within a single continuous memory segment. In this case, `Window_Descriptor` byte is skipped, but `Frame_Content_Size` is necessarily present. As a consequence, the decoder must allocate a memory segment -of size equal or bigger than `Frame_Content_Size`. +of size equal or larger than `Frame_Content_Size`. In order to preserve the decoder from unreasonable memory requirements, a decoder is allowed to reject a compressed frame which requests a memory size beyond decoder's authorized range. For broader compatibility, decoders are recommended to support memory sizes of at least 8 MB. This is only a recommendation, each decoder is free to support higher or lower limits, depending on local limitations. __`Unused_bit`__ The value of this bit should be set to zero. A decoder compliant with this specification version shall not interpret it. It might be used in a future version, to signal a property which is not mandatory to properly decode the frame. __`Reserved_bit`__ This bit is reserved for some future feature. Its value _must be zero_. A decoder compliant with this specification version must ensure it is not set. This bit may be used in a future revision, to signal a feature that must be interpreted to decode the frame correctly. __`Content_Checksum_flag`__ If this flag is set, a 32-bits `Content_Checksum` will be present at frame's end. See `Content_Checksum` paragraph. __`Dictionary_ID_flag`__ This is a 2-bits flag (`= FHD & 3`), telling if a dictionary ID is provided within the header. It also specifies the size of this field as `Field_Size`. |`Flag_Value`| 0 | 1 | 2 | 3 | | ---------- | --- | --- | --- | --- | |`Field_Size`| 0 | 1 | 2 | 4 | #### `Window_Descriptor` Provides guarantees on minimum memory buffer required to decompress a frame. This information is important for decoders to allocate enough memory. The `Window_Descriptor` byte is optional. When `Single_Segment_flag` is set, `Window_Descriptor` is not present. In this case, `Window_Size` is `Frame_Content_Size`, which can be any value from 0 to 2^64-1 bytes (16 ExaBytes). | Bit numbers | 7-3 | 2-0 | | ----------- | ---------- | ---------- | | Field name | `Exponent` | `Mantissa` | The minimum memory buffer size is called `Window_Size`. It is described by the following formulas : ``` windowLog = 10 + Exponent; windowBase = 1 << windowLog; windowAdd = (windowBase / 8) * Mantissa; Window_Size = windowBase + windowAdd; ``` The minimum `Window_Size` is 1 KB. The maximum `Window_Size` is `(1<<41) + 7*(1<<38)` bytes, which is 3.75 TB. To properly decode compressed data, a decoder will need to allocate a buffer of at least `Window_Size` bytes. In order to preserve decoder from unreasonable memory requirements, a decoder is allowed to reject a compressed frame which requests a memory size beyond decoder's authorized range. For improved interoperability, decoders are recommended to be compatible with `Window_Size >= 8 MB`, and encoders are recommended to not request more than 8 MB. It's merely a recommendation though, decoders are free to support larger or lower limits, depending on local limitations. #### `Dictionary_ID` This is a variable size field, which contains the ID of the dictionary required to properly decode the frame. `Dictionary_ID` field is optional. When it's not present, it's up to the decoder to make sure it uses the correct dictionary. Field size depends on `Dictionary_ID_flag`. 1 byte can represent an ID 0-255. 2 bytes can represent an ID 0-65535. 4 bytes can represent an ID 0-4294967295. Format is __little-endian__. It's allowed to represent a small ID (for example `13`) with a large 4-bytes dictionary ID, even if it is less efficient. _Reserved ranges :_ If the frame is going to be distributed in a private environment, any dictionary ID can be used. However, for public distribution of compressed frames using a dictionary, the following ranges are reserved and shall not be used : - low range : `<= 32767` - high range : `>= (1 << 31)` #### `Frame_Content_Size` This is the original (uncompressed) size. This information is optional. `Frame_Content_Size` uses a variable number of bytes, provided by `FCS_Field_Size`. `FCS_Field_Size` is provided by the value of `Frame_Content_Size_flag`. `FCS_Field_Size` can be equal to 0 (not present), 1, 2, 4 or 8 bytes. | `FCS_Field_Size` | Range | | ---------------- | ---------- | | 0 | unknown | | 1 | 0 - 255 | | 2 | 256 - 65791| | 4 | 0 - 2^32-1 | | 8 | 0 - 2^64-1 | `Frame_Content_Size` format is __little-endian__. When `FCS_Field_Size` is 1, 4 or 8 bytes, the value is read directly. When `FCS_Field_Size` is 2, _the offset of 256 is added_. It's allowed to represent a small size (for example `18`) using any compatible variant. Blocks ------- After `Magic_Number` and `Frame_Header`, there are some number of blocks. Each frame must have at least one block, but there is no upper limit on the number of blocks per frame. The structure of a block is as follows: | `Block_Header` | `Block_Content` | |:--------------:|:---------------:| | 3 bytes | n bytes | `Block_Header` uses 3 bytes, written using __little-endian__ convention. It contains 3 fields : | `Last_Block` | `Block_Type` | `Block_Size` | |:------------:|:------------:|:------------:| | bit 0 | bits 1-2 | bits 3-23 | __`Last_Block`__ The lowest bit signals if this block is the last one. The frame will end after this last block. It may be followed by an optional `Content_Checksum` (see [Zstandard Frames](#zstandard-frames)). __`Block_Type`__ The next 2 bits represent the `Block_Type`. There are 4 block types : | Value | 0 | 1 | 2 | 3 | | ------------ | ----------- | ----------- | ------------------ | --------- | | `Block_Type` | `Raw_Block` | `RLE_Block` | `Compressed_Block` | `Reserved`| - `Raw_Block` - this is an uncompressed block. `Block_Content` contains `Block_Size` bytes. - `RLE_Block` - this is a single byte, repeated `Block_Size` times. `Block_Content` consists of a single byte. On the decompression side, this byte must be repeated `Block_Size` times. - `Compressed_Block` - this is a [Zstandard compressed block](#compressed-blocks), explained later on. `Block_Size` is the length of `Block_Content`, the compressed data. The decompressed size is not known, but its maximum possible value is guaranteed (see below) - `Reserved` - this is not a block. This value cannot be used with current version of this specification. __`Block_Size`__ The upper 21 bits of `Block_Header` represent the `Block_Size`. Block sizes must respect a few rules : - For `Compressed_Block`, `Block_Size` is always strictly less than decompressed size. - Block decompressed size is always <= `Window_Size` - Block decompressed size is always <= 128 KB. A block can contain any number of bytes (even empty), up to `Block_Maximum_Decompressed_Size`, which is the smallest of : - `Window_Size` - 128 KB Compressed Blocks ----------------- To decompress a compressed block, the compressed size must be provided from `Block_Size` field within `Block_Header`. A compressed block consists of 2 sections : - [Literals Section](#literals-section) - [Sequences Section](#sequences-section) The results of the two sections are then combined to produce the decompressed data in [Sequence Execution](#sequence-execution) #### Prerequisites To decode a compressed block, the following elements are necessary : - Previous decoded data, up to a distance of `Window_Size`, or all previously decoded data when `Single_Segment_flag` is set. - List of "recent offsets" from previous `Compressed_Block`. - Decoding tables of previous `Compressed_Block` for each symbol type (literals, literals lengths, match lengths, offsets). Literals Section ---------------- All literals are regrouped in the first part of the block. They can be decoded first, and then copied during [Sequence Execution], or they can be decoded on the flow during [Sequence Execution]. Literals can be stored uncompressed or compressed using Huffman prefix codes. When compressed, an optional tree description can be present, followed by 1 or 4 streams. | `Literals_Section_Header` | [`Huffman_Tree_Description`] | Stream1 | [Stream2] | [Stream3] | [Stream4] | | ------------------------- | ---------------------------- | ------- | --------- | --------- | --------- | #### `Literals_Section_Header` Header is in charge of describing how literals are packed. It's a byte-aligned variable-size bitfield, ranging from 1 to 5 bytes, using __little-endian__ convention. | `Literals_Block_Type` | `Size_Format` | `Regenerated_Size` | [`Compressed_Size`] | | --------------------- | ------------- | ------------------ | ------------------- | | 2 bits | 1 - 2 bits | 5 - 20 bits | 0 - 18 bits | In this representation, bits on the left are the lowest bits. __`Literals_Block_Type`__ This field uses 2 lowest bits of first byte, describing 4 different block types : | `Literals_Block_Type` | Value | | --------------------------- | ----- | | `Raw_Literals_Block` | 0 | | `RLE_Literals_Block` | 1 | | `Compressed_Literals_Block` | 2 | | `Treeless_Literals_Block` | 3 | - `Raw_Literals_Block` - Literals are stored uncompressed. - `RLE_Literals_Block` - Literals consist of a single byte value repeated `Regenerated_Size` times. - `Compressed_Literals_Block` - This is a standard Huffman-compressed block, starting with a Huffman tree description. See details below. - `Treeless_Literals_Block` - This is a Huffman-compressed block, using Huffman tree _from previous Huffman-compressed literals block_. `Huffman_Tree_Description` will be skipped. Note: If this mode is triggered without any previous Huffman-table in the frame (or [dictionary](#dictionary-format)), this should be treated as data corruption. __`Size_Format`__ `Size_Format` is divided into 2 families : - For `Raw_Literals_Block` and `RLE_Literals_Block`, it's only necessary to decode `Regenerated_Size`. There is no `Compressed_Size` field. - For `Compressed_Block` and `Treeless_Literals_Block`, it's required to decode both `Compressed_Size` and `Regenerated_Size` (the decompressed size). It's also necessary to decode the number of streams (1 or 4). For values spanning several bytes, convention is __little-endian__. __`Size_Format` for `Raw_Literals_Block` and `RLE_Literals_Block`__ : - Value ?0 : `Size_Format` uses 1 bit. `Regenerated_Size` uses 5 bits (0-31). `Literals_Section_Header` has 1 byte. `Regenerated_Size = Header[0]>>3` - Value 01 : `Size_Format` uses 2 bits. `Regenerated_Size` uses 12 bits (0-4095). `Literals_Section_Header` has 2 bytes. `Regenerated_Size = (Header[0]>>4) + (Header[1]<<4)` - Value 11 : `Size_Format` uses 2 bits. `Regenerated_Size` uses 20 bits (0-1048575). `Literals_Section_Header` has 3 bytes. `Regenerated_Size = (Header[0]>>4) + (Header[1]<<4) + (Header[2]<<12)` Only Stream1 is present for these cases. Note : it's allowed to represent a short value (for example `13`) using a long format, even if it's less efficient. __`Size_Format` for `Compressed_Literals_Block` and `Treeless_Literals_Block`__ : - Value 00 : _A single stream_. Both `Regenerated_Size` and `Compressed_Size` use 10 bits (0-1023). `Literals_Section_Header` has 3 bytes. - Value 01 : 4 streams. Both `Regenerated_Size` and `Compressed_Size` use 10 bits (0-1023). `Literals_Section_Header` has 3 bytes. - Value 10 : 4 streams. Both `Regenerated_Size` and `Compressed_Size` use 14 bits (0-16383). `Literals_Section_Header` has 4 bytes. - Value 11 : 4 streams. Both `Regenerated_Size` and `Compressed_Size` use 18 bits (0-262143). `Literals_Section_Header` has 5 bytes. Both `Compressed_Size` and `Regenerated_Size` fields follow __little-endian__ convention. Note: `Compressed_Size` __includes__ the size of the Huffman Tree description _when_ it is present. ### Raw Literals Block The data in Stream1 is `Regenerated_Size` bytes long, it contains the raw literals data to be used during [Sequence Execution]. ### RLE Literals Block Stream1 consists of a single byte which should be repeated `Regenerated_Size` times to generate the decoded literals. ### Compressed Literals Block and Treeless Literals Block Both of these modes contain Huffman encoded data. `Treeless_Literals_Block` does not have a `Huffman_Tree_Description`. #### `Huffman_Tree_Description` This section is only present when `Literals_Block_Type` type is `Compressed_Literals_Block` (`2`). The format of the Huffman tree description can be found at [Huffman Tree description](#huffman-tree-description). The size of `Huffman_Tree_Description` is determined during decoding process, it must be used to determine where streams begin. `Total_Streams_Size = Compressed_Size - Huffman_Tree_Description_Size`. For `Treeless_Literals_Block`, the Huffman table comes from previously compressed literals block. Huffman compressed data consists of either 1 or 4 Huffman-coded streams. If only one stream is present, it is a single bitstream occupying the entire remaining portion of the literals block, encoded as described within [Huffman-Coded Streams](#huffman-coded-streams). If there are four streams, the literals section header only provides enough information to know the decompressed and compressed sizes of all four streams _combined_. The decompressed size of each stream is equal to `(Regenerated_Size+3)/4`, except for the last stream which may be up to 3 bytes smaller, to reach a total decompressed size as specified in `Regenerated_Size`. The compressed size of each stream is provided explicitly: the first 6 bytes of the compressed data consist of three 2-byte __little-endian__ fields, describing the compressed sizes of the first three streams. `Stream4_Size` is computed from total `Total_Streams_Size` minus sizes of other streams. `Stream4_Size = Total_Streams_Size - 6 - Stream1_Size - Stream2_Size - Stream3_Size`. Note: remember that `Total_Streams_Size` can be smaller than `Compressed_Size` in header, because `Compressed_Size` also contains `Huffman_Tree_Description_Size` when it is present. Each of these 4 bitstreams is then decoded independently as a Huffman-Coded stream, as described at [Huffman-Coded Streams](#huffman-coded-streams) Sequences Section ----------------- A compressed block is a succession of _sequences_ . A sequence is a literal copy command, followed by a match copy command. A literal copy command specifies a length. It is the number of bytes to be copied (or extracted) from the Literals Section. A match copy command specifies an offset and a length. When all _sequences_ are decoded, if there are literals left in the _literal section_, these bytes are added at the end of the block. This is described in more detail in [Sequence Execution](#sequence-execution) The `Sequences_Section` regroup all symbols required to decode commands. There are 3 symbol types : literals lengths, offsets and match lengths. They are encoded together, interleaved, in a single _bitstream_. The `Sequences_Section` starts by a header, followed by optional probability tables for each symbol type, followed by the bitstream. | `Sequences_Section_Header` | [`Literals_Length_Table`] | [`Offset_Table`] | [`Match_Length_Table`] | bitStream | | -------------------------- | ------------------------- | ---------------- | ---------------------- | --------- | To decode the `Sequences_Section`, it's required to know its size. This size is deduced from `Block_Size - Literals_Section_Size`. #### `Sequences_Section_Header` Consists of 2 items: - `Number_of_Sequences` - Symbol compression modes __`Number_of_Sequences`__ This is a variable size field using between 1 and 3 bytes. Let's call its first byte `byte0`. - `if (byte0 == 0)` : there are no sequences. The sequence section stops there. Decompressed content is defined entirely as Literals Section content. - `if (byte0 < 128)` : `Number_of_Sequences = byte0` . Uses 1 byte. - `if (byte0 < 255)` : `Number_of_Sequences = ((byte0-128) << 8) + byte1` . Uses 2 bytes. - `if (byte0 == 255)`: `Number_of_Sequences = byte1 + (byte2<<8) + 0x7F00` . Uses 3 bytes. __Symbol compression modes__ This is a single byte, defining the compression mode of each symbol type. |Bit number| 7-6 | 5-4 | 3-2 | 1-0 | | -------- | ----------------------- | -------------- | -------------------- | ---------- | |Field name| `Literals_Lengths_Mode` | `Offsets_Mode` | `Match_Lengths_Mode` | `Reserved` | The last field, `Reserved`, must be all-zeroes. `Literals_Lengths_Mode`, `Offsets_Mode` and `Match_Lengths_Mode` define the `Compression_Mode` of literals lengths, offsets, and match lengths symbols respectively. They follow the same enumeration : | Value | 0 | 1 | 2 | 3 | | ------------------ | ----------------- | ---------- | --------------------- | ------------- | | `Compression_Mode` | `Predefined_Mode` | `RLE_Mode` | `FSE_Compressed_Mode` | `Repeat_Mode` | - `Predefined_Mode` : A predefined FSE distribution table is used, defined in [default distributions](#default-distributions). No distribution table will be present. - `RLE_Mode` : The table description consists of a single byte. This code will be repeated for all sequences. - `Repeat_Mode` : The table used in the previous compressed block will be used again. No distribution table will be present. Note: this includes RLE mode, so if `Repeat_Mode` follows `RLE_Mode`, the same symbol will be repeated. If this mode is used without any previous sequence table in the frame (or [dictionary](#dictionary-format)) to repeat, this should be treated as corruption. - `FSE_Compressed_Mode` : standard FSE compression. A distribution table will be present. The format of this distribution table is described in [FSE Table Description](#fse-table-description). Note that the maximum allowed accuracy log for literals length and match length tables is 9, and the maximum accuracy log for the offsets table is 8. #### The codes for literals lengths, match lengths, and offsets. Each symbol is a _code_ in its own context, which specifies `Baseline` and `Number_of_Bits` to add. _Codes_ are FSE compressed, and interleaved with raw additional bits in the same bitstream. ##### Literals length codes Literals length codes are values ranging from `0` to `35` included. They define lengths from 0 to 131071 bytes. The literals length is equal to the decoded `Baseline` plus the result of reading `Number_of_Bits` bits from the bitstream, as a __little-endian__ value. | `Literals_Length_Code` | 0-15 | | ---------------------- | ---------------------- | | length | `Literals_Length_Code` | | `Number_of_Bits` | 0 | | `Literals_Length_Code` | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | | ---------------------- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | | `Baseline` | 16 | 18 | 20 | 22 | 24 | 28 | 32 | 40 | | `Number_of_Bits` | 1 | 1 | 1 | 1 | 2 | 2 | 3 | 3 | | `Literals_Length_Code` | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | | ---------------------- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | | `Baseline` | 48 | 64 | 128 | 256 | 512 | 1024 | 2048 | 4096 | | `Number_of_Bits` | 4 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | | `Literals_Length_Code` | 32 | 33 | 34 | 35 | | ---------------------- | ---- | ---- | ---- | ---- | | `Baseline` | 8192 |16384 |32768 |65536 | | `Number_of_Bits` | 13 | 14 | 15 | 16 | ##### Match length codes Match length codes are values ranging from `0` to `52` included. They define lengths from 3 to 131074 bytes. The match length is equal to the decoded `Baseline` plus the result of reading `Number_of_Bits` bits from the bitstream, as a __little-endian__ value. | `Match_Length_Code` | 0-31 | | ------------------- | ----------------------- | | value | `Match_Length_Code` + 3 | | `Number_of_Bits` | 0 | | `Match_Length_Code` | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | | ------------------- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | | `Baseline` | 35 | 37 | 39 | 41 | 43 | 47 | 51 | 59 | | `Number_of_Bits` | 1 | 1 | 1 | 1 | 2 | 2 | 3 | 3 | | `Match_Length_Code` | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | | ------------------- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | | `Baseline` | 67 | 83 | 99 | 131 | 259 | 515 | 1027 | 2051 | | `Number_of_Bits` | 4 | 4 | 5 | 7 | 8 | 9 | 10 | 11 | | `Match_Length_Code` | 48 | 49 | 50 | 51 | 52 | | ------------------- | ---- | ---- | ---- | ---- | ---- | | `Baseline` | 4099 | 8195 |16387 |32771 |65539 | | `Number_of_Bits` | 12 | 13 | 14 | 15 | 16 | ##### Offset codes Offset codes are values ranging from `0` to `N`. A decoder is free to limit its maximum `N` supported. Recommendation is to support at least up to `22`. For information, at the time of this writing. the reference decoder supports a maximum `N` value of `28` in 64-bits mode. An offset code is also the number of additional bits to read in __little-endian__ fashion, and can be translated into an `Offset_Value` using the following formulas : ``` Offset_Value = (1 << offsetCode) + readNBits(offsetCode); if (Offset_Value > 3) offset = Offset_Value - 3; ``` It means that maximum `Offset_Value` is `(2^(N+1))-1` and it supports back-reference distance up to `(2^(N+1))-4` but is limited by [maximum back-reference distance](#window_descriptor). `Offset_Value` from 1 to 3 are special : they define "repeat codes". This is described in more detail in [Repeat Offsets](#repeat-offsets). #### Decoding Sequences FSE bitstreams are read in reverse direction than written. In zstd, the compressor writes bits forward into a block and the decompressor must read the bitstream _backwards_. To find the start of the bitstream it is therefore necessary to know the offset of the last byte of the block which can be found by counting `Block_Size` bytes after the block header. After writing the last bit containing information, the compressor writes a single `1`-bit and then fills the byte with 0-7 `0` bits of padding. The last byte of the compressed bitstream cannot be `0` for that reason. When decompressing, the last byte containing the padding is the first byte to read. The decompressor needs to skip 0-7 initial `0`-bits and the first `1`-bit it occurs. Afterwards, the useful part of the bitstream begins. FSE decoding requires a 'state' to be carried from symbol to symbol. For more explanation on FSE decoding, see the [FSE section](#fse). For sequence decoding, a separate state keeps track of each literal lengths, offsets, and match lengths symbols. Some FSE primitives are also used. For more details on the operation of these primitives, see the [FSE section](#fse). ##### Starting states The bitstream starts with initial FSE state values, each using the required number of bits in their respective _accuracy_, decoded previously from their normalized distribution. It starts by `Literals_Length_State`, followed by `Offset_State`, and finally `Match_Length_State`. Reminder : always keep in mind that all values are read _backward_, so the 'start' of the bitstream is at the highest position in memory, immediately before the last `1`-bit for padding. After decoding the starting states, a single sequence is decoded `Number_Of_Sequences` times. These sequences are decoded in order from first to last. Since the compressor writes the bitstream in the forward direction, this means the compressor must encode the sequences starting with the last one and ending with the first. ##### Decoding a sequence For each of the symbol types, the FSE state can be used to determine the appropriate code. The code then defines the baseline and number of bits to read for each type. See the [description of the codes] for how to determine these values. [description of the codes]: #the-codes-for-literals-lengths-match-lengths-and-offsets Decoding starts by reading the `Number_of_Bits` required to decode `Offset`. It then does the same for `Match_Length`, and then for `Literals_Length`. This sequence is then used for [sequence execution](#sequence-execution). If it is not the last sequence in the block, the next operation is to update states. Using the rules pre-calculated in the decoding tables, `Literals_Length_State` is updated, followed by `Match_Length_State`, and then `Offset_State`. See the [FSE section](#fse) for details on how to update states from the bitstream. This operation will be repeated `Number_of_Sequences` times. At the end, the bitstream shall be entirely consumed, otherwise the bitstream is considered corrupted. #### Default Distributions If `Predefined_Mode` is selected for a symbol type, its FSE decoding table is generated from a predefined distribution table defined here. For details on how to convert this distribution into a decoding table, see the [FSE section]. [FSE section]: #from-normalized-distribution-to-decoding-tables ##### Literals Length The decoding table uses an accuracy log of 6 bits (64 states). ``` short literalsLength_defaultDistribution[36] = { 4, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 1, 1, 1, 1, 1, -1,-1,-1,-1 }; ``` ##### Match Length The decoding table uses an accuracy log of 6 bits (64 states). ``` short matchLengths_defaultDistribution[53] = { 1, 4, 3, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,-1,-1, -1,-1,-1,-1,-1 }; ``` ##### Offset Codes The decoding table uses an accuracy log of 5 bits (32 states), and supports a maximum `N` value of 28, allowing offset values up to 536,870,908 . If any sequence in the compressed block requires a larger offset than this, it's not possible to use the default distribution to represent it. ``` short offsetCodes_defaultDistribution[29] = { 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,-1,-1,-1,-1,-1 }; ``` Sequence Execution ------------------ Once literals and sequences have been decoded, they are combined to produce the decoded content of a block. Each sequence consists of a tuple of (`literals_length`, `offset_value`, `match_length`), decoded as described in the [Sequences Section](#sequences-section). To execute a sequence, first copy `literals_length` bytes from the literals section to the output. Then `match_length` bytes are copied from previous decoded data. The offset to copy from is determined by `offset_value`: if `offset_value > 3`, then the offset is `offset_value - 3`. If `offset_value` is from 1-3, the offset is a special repeat offset value. See the [repeat offset](#repeat-offsets) section for how the offset is determined in this case. The offset is defined as from the current position, so an offset of 6 and a match length of 3 means that 3 bytes should be copied from 6 bytes back. Note that all offsets leading to previously decoded data must be smaller than `Window_Size` defined in `Frame_Header_Descriptor`. #### Repeat offsets As seen in [Sequence Execution](#sequence-execution), the first 3 values define a repeated offset and we will call them `Repeated_Offset1`, `Repeated_Offset2`, and `Repeated_Offset3`. They are sorted in recency order, with `Repeated_Offset1` meaning "most recent one". If `offset_value == 1`, then the offset used is `Repeated_Offset1`, etc. There is an exception though, when current sequence's `literals_length = 0`. In this case, repeated offsets are shifted by one, so an `offset_value` of 1 means `Repeated_Offset2`, an `offset_value` of 2 means `Repeated_Offset3`, and an `offset_value` of 3 means `Repeated_Offset1 - 1_byte`. For the first block, the starting offset history is populated with the following values : 1, 4 and 8 (in order). Then each block gets its starting offset history from the ending values of the most recent `Compressed_Block`. Note that blocks which are not `Compressed_Block` are skipped, they do not contribute to offset history. [Offset Codes]: #offset-codes ###### Offset updates rules The newest offset takes the lead in offset history, shifting others back (up to its previous place if it was already present). This means that when `Repeated_Offset1` (most recent) is used, history is unmodified. When `Repeated_Offset2` is used, it's swapped with `Repeated_Offset1`. If any other offset is used, it becomes `Repeated_Offset1` and the rest are shift back by one. Skippable Frames ---------------- | `Magic_Number` | `Frame_Size` | `User_Data` | |:--------------:|:------------:|:-----------:| | 4 bytes | 4 bytes | n bytes | Skippable frames allow the insertion of user-defined data into a flow of concatenated frames. Its design is pretty straightforward, with the sole objective to allow the decoder to quickly skip over user-defined data and continue decoding. Skippable frames defined in this specification are compatible with [LZ4] ones. [LZ4]:http://www.lz4.org __`Magic_Number`__ 4 Bytes, __little-endian__ format. Value : 0x184D2A5?, which means any value from 0x184D2A50 to 0x184D2A5F. All 16 values are valid to identify a skippable frame. __`Frame_Size`__ This is the size, in bytes, of the following `User_Data` (without including the magic number nor the size field itself). This field is represented using 4 Bytes, __little-endian__ format, unsigned 32-bits. This means `User_Data` can’t be bigger than (2^32-1) bytes. __`User_Data`__ The `User_Data` can be anything. Data will just be skipped by the decoder. Entropy Encoding ---------------- Two types of entropy encoding are used by the Zstandard format: FSE, and Huffman coding. FSE --- FSE, short for Finite State Entropy, is an entropy codec based on [ANS]. FSE encoding/decoding involves a state that is carried over between symbols, so decoding must be done in the opposite direction as encoding. Therefore, all FSE bitstreams are read from end to beginning. For additional details on FSE, see [Finite State Entropy]. [Finite State Entropy]:https://github.com/Cyan4973/FiniteStateEntropy/ FSE decoding involves a decoding table which has a power of 2 size, and contain three elements: `Symbol`, `Num_Bits`, and `Baseline`. The `log2` of the table size is its `Accuracy_Log`. The FSE state represents an index in this table. To obtain the initial state value, consume `Accuracy_Log` bits from the stream as a __little-endian__ value. The next symbol in the stream is the `Symbol` indicated in the table for that state. To obtain the next state value, the decoder should consume `Num_Bits` bits from the stream as a __little-endian__ value and add it to `Baseline`. [ANS]: https://en.wikipedia.org/wiki/Asymmetric_Numeral_Systems ### FSE Table Description To decode FSE streams, it is necessary to construct the decoding table. The Zstandard format encodes FSE table descriptions as follows: An FSE distribution table describes the probabilities of all symbols from `0` to the last present one (included) on a normalized scale of `1 << Accuracy_Log` . It's a bitstream which is read forward, in __little-endian__ fashion. It's not necessary to know its exact size, since it will be discovered and reported by the decoding process. The bitstream starts by reporting on which scale it operates. `Accuracy_Log = low4bits + 5`. Then follows each symbol value, from `0` to last present one. The number of bits used by each field is variable. It depends on : - Remaining probabilities + 1 : __example__ : Presuming an `Accuracy_Log` of 8, and presuming 100 probabilities points have already been distributed, the decoder may read any value from `0` to `255 - 100 + 1 == 156` (inclusive). Therefore, it must read `log2sup(156) == 8` bits. - Value decoded : small values use 1 less bit : __example__ : Presuming values from 0 to 156 (inclusive) are possible, 255-156 = 99 values are remaining in an 8-bits field. They are used this way : first 99 values (hence from 0 to 98) use only 7 bits, values from 99 to 156 use 8 bits. This is achieved through this scheme : | Value read | Value decoded | Number of bits used | | ---------- | ------------- | ------------------- | | 0 - 98 | 0 - 98 | 7 | | 99 - 127 | 99 - 127 | 8 | | 128 - 226 | 0 - 98 | 7 | | 227 - 255 | 128 - 156 | 8 | Symbols probabilities are read one by one, in order. Probability is obtained from Value decoded by following formula : `Proba = value - 1` It means value `0` becomes negative probability `-1`. `-1` is a special probability, which means "less than 1". Its effect on distribution table is described in the [next section]. For the purpose of calculating total allocated probability points, it counts as one. [next section]:#from-normalized-distribution-to-decoding-tables When a symbol has a __probability__ of `zero`, it is followed by a 2-bits repeat flag. This repeat flag tells how many probabilities of zeroes follow the current one. It provides a number ranging from 0 to 3. If it is a 3, another 2-bits repeat flag follows, and so on. When last symbol reaches cumulated total of `1 << Accuracy_Log`, decoding is complete. If the last symbol makes cumulated total go above `1 << Accuracy_Log`, distribution is considered corrupted. Then the decoder can tell how many bytes were used in this process, and how many symbols are present. The bitstream consumes a round number of bytes. Any remaining bit within the last byte is just unused. ##### From normalized distribution to decoding tables The distribution of normalized probabilities is enough to create a unique decoding table. It follows the following build rule : The table has a size of `Table_Size = 1 << Accuracy_Log`. Each cell describes the symbol decoded, and instructions to get the next state. Symbols are scanned in their natural order for "less than 1" probabilities. Symbols with this probability are being attributed a single cell, starting from the end of the table. These symbols define a full state reset, reading `Accuracy_Log` bits. All remaining symbols are sorted in their natural order. Starting from symbol `0` and table position `0`, each symbol gets attributed as many cells as its probability. Cell allocation is spreaded, not linear : each successor position follow this rule : ``` position += (tableSize>>1) + (tableSize>>3) + 3; position &= tableSize-1; ``` A position is skipped if already occupied by a "less than 1" probability symbol. `position` does not reset between symbols, it simply iterates through each position in the table, switching to the next symbol when enough states have been allocated to the current one. The result is a list of state values. Each state will decode the current symbol. To get the `Number_of_Bits` and `Baseline` required for next state, it's first necessary to sort all states in their natural order. The lower states will need 1 more bit than higher ones. __Example__ : Presuming a symbol has a probability of 5. It receives 5 state values. States are sorted in natural order. Next power of 2 is 8. Space of probabilities is divided into 8 equal parts. Presuming the `Accuracy_Log` is 7, it defines 128 states. Divided by 8, each share is 16 large. In order to reach 8, 8-5=3 lowest states will count "double", taking shares twice larger, requiring one more bit in the process. Numbering starts from higher states using less bits. | state order | 0 | 1 | 2 | 3 | 4 | | ---------------- | ----- | ----- | ------ | ---- | ----- | | width | 32 | 32 | 32 | 16 | 16 | | `Number_of_Bits` | 5 | 5 | 5 | 4 | 4 | | range number | 2 | 4 | 6 | 0 | 1 | | `Baseline` | 32 | 64 | 96 | 0 | 16 | | range | 32-63 | 64-95 | 96-127 | 0-15 | 16-31 | The next state is determined from current state by reading the required `Number_of_Bits`, and adding the specified `Baseline`. See [Appendix A] for the results of this process applied to the default distributions. [Appendix A]: #appendix-a---decoding-tables-for-predefined-codes Huffman Coding -------------- Zstandard Huffman-coded streams are read backwards, similar to the FSE bitstreams. Therefore, to find the start of the bitstream, it is therefore to know the offset of the last byte of the Huffman-coded stream. After writing the last bit containing information, the compressor writes a single `1`-bit and then fills the byte with 0-7 `0` bits of padding. The last byte of the compressed bitstream cannot be `0` for that reason. When decompressing, the last byte containing the padding is the first byte to read. The decompressor needs to skip 0-7 initial `0`-bits and the first `1`-bit it occurs. Afterwards, the useful part of the bitstream begins. The bitstream contains Huffman-coded symbols in __little-endian__ order, with the codes defined by the method below. ### Huffman Tree Description Prefix coding represents symbols from an a priori known alphabet by bit sequences (codewords), one codeword for each symbol, in a manner such that different symbols may be represented by bit sequences of different lengths, but a parser can always parse an encoded string unambiguously symbol-by-symbol. Given an alphabet with known symbol frequencies, the Huffman algorithm allows the construction of an optimal prefix code using the fewest bits of any possible prefix codes for that alphabet. Prefix code must not exceed a maximum code length. More bits improve accuracy but cost more header size, and require more memory or more complex decoding operations. This specification limits maximum code length to 11 bits. ##### Representation All literal values from zero (included) to last present one (excluded) are represented by `Weight` with values from `0` to `Max_Number_of_Bits`. Transformation from `Weight` to `Number_of_Bits` follows this formula : ``` Number_of_Bits = Weight ? (Max_Number_of_Bits + 1 - Weight) : 0 ``` The last symbol's `Weight` is deduced from previously decoded ones, by completing to the nearest power of 2. This power of 2 gives `Max_Number_of_Bits`, the depth of the current tree. __Example__ : Let's presume the following Huffman tree must be described : | literal | 0 | 1 | 2 | 3 | 4 | 5 | | ---------------- | --- | --- | --- | --- | --- | --- | | `Number_of_Bits` | 1 | 2 | 3 | 0 | 4 | 4 | The tree depth is 4, since its smallest element uses 4 bits. Value `5` will not be listed as it can be determined from the values for 0-4, nor will values above `5` as they are all 0. Values from `0` to `4` will be listed using `Weight` instead of `Number_of_Bits`. Weight formula is : ``` Weight = Number_of_Bits ? (Max_Number_of_Bits + 1 - Number_of_Bits) : 0 ``` It gives the following series of weights : | literal | 0 | 1 | 2 | 3 | 4 | | -------- | --- | --- | --- | --- | --- | | `Weight` | 4 | 3 | 2 | 0 | 1 | The decoder will do the inverse operation : having collected weights of literals from `0` to `4`, it knows the last literal, `5`, is present with a non-zero weight. The weight of `5` can be determined by advancing to the next power of 2. The sum of `2^(Weight-1)` (excluding 0's) is : `8 + 4 + 2 + 0 + 1 = 15`. Nearest power of 2 is 16. Therefore, `Max_Number_of_Bits = 4` and `Weight[5] = 1`. ##### Huffman Tree header This is a single byte value (0-255), which describes how to decode the list of weights. - if `headerByte` >= 128 : this is a direct representation, where each `Weight` is written directly as a 4 bits field (0-15). They are encoded forward, 2 weights to a byte with the first weight taking the top four bits and the second taking the bottom four (e.g. the following operations could be used to read the weights: `Weight[0] = (Byte[0] >> 4), Weight[1] = (Byte[0] & 0xf)`, etc.). The full representation occupies `((Number_of_Symbols+1)/2)` bytes, meaning it uses a last full byte even if `Number_of_Symbols` is odd. `Number_of_Symbols = headerByte - 127`. Note that maximum `Number_of_Symbols` is 255-127 = 128. A larger series must necessarily use FSE compression. - if `headerByte` < 128 : the series of weights is compressed by FSE. The length of the FSE-compressed series is equal to `headerByte` (0-127). ##### Finite State Entropy (FSE) compression of Huffman weights In this case, the series of Huffman weights is compressed using FSE compression. It's a single bitstream with 2 interleaved states, sharing a single distribution table. To decode an FSE bitstream, it is necessary to know its compressed size. Compressed size is provided by `headerByte`. It's also necessary to know its _maximum possible_ decompressed size, which is `255`, since literal values span from `0` to `255`, and last symbol's weight is not represented. An FSE bitstream starts by a header, describing probabilities distribution. It will create a Decoding Table. For a list of Huffman weights, the maximum accuracy log is 7 bits. For more description see the [FSE header description](#fse-table-description) The Huffman header compression uses 2 states, which share the same FSE distribution table. The first state (`State1`) encodes the even indexed symbols, and the second (`State2`) encodes the odd indexes. `State1` is initialized first, and then `State2`, and they take turns decoding a single symbol and updating their state. For more details on these FSE operations, see the [FSE section](#fse). The number of symbols to decode is determined by tracking bitStream overflow condition: If updating state after decoding a symbol would require more bits than remain in the stream, it is assumed that extra bits are 0. Then, the symbols for each of the final states are decoded and the process is complete. ##### Conversion from weights to Huffman prefix codes All present symbols shall now have a `Weight` value. It is possible to transform weights into Number_of_Bits, using this formula: ``` Number_of_Bits = Number_of_Bits ? Max_Number_of_Bits + 1 - Weight : 0 ``` Symbols are sorted by `Weight`. Within same `Weight`, symbols keep natural order. Symbols with a `Weight` of zero are removed. Then, starting from lowest weight, prefix codes are distributed in order. __Example__ : Let's presume the following list of weights has been decoded : | Literal | 0 | 1 | 2 | 3 | 4 | 5 | | -------- | --- | --- | --- | --- | --- | --- | | `Weight` | 4 | 3 | 2 | 0 | 1 | 1 | Sorted by weight and then natural order, it gives the following distribution : | Literal | 3 | 4 | 5 | 2 | 1 | 0 | | ---------------- | --- | --- | --- | --- | --- | ---- | | `Weight` | 0 | 1 | 1 | 2 | 3 | 4 | | `Number_of_Bits` | 0 | 4 | 4 | 3 | 2 | 1 | | prefix codes | N/A | 0000| 0001| 001 | 01 | 1 | ### Huffman-coded Streams Given a Huffman decoding table, it's possible to decode a Huffman-coded stream. Each bitstream must be read _backward_, that is starting from the end down to the beginning. Therefore it's necessary to know the size of each bitstream. It's also necessary to know exactly which _bit_ is the latest. This is detected by a final bit flag : the highest bit of latest byte is a final-bit-flag. Consequently, a last byte of `0` is not possible. And the final-bit-flag itself is not part of the useful bitstream. Hence, the last byte contains between 0 and 7 useful bits. Starting from the end, it's possible to read the bitstream in a __little-endian__ fashion, keeping track of already used bits. Since the bitstream is encoded in reverse order, starting from the end read symbols in forward order. For example, if the literal sequence "0145" was encoded using above prefix code, it would be encoded (in reverse order) as: |Symbol | 5 | 4 | 1 | 0 | Padding | |--------|------|------|----|---|---------| |Encoding|`0000`|`0001`|`01`|`1`| `00001` | Resulting in following 2-bytes bitstream : ``` 00010000 00001101 ``` Here is an alternative representation with the symbol codes separated by underscore: ``` 0001_0000 00001_1_01 ``` Reading highest `Max_Number_of_Bits` bits, it's possible to compare extracted value to decoding table, determining the symbol to decode and number of bits to discard. The process continues up to reading the required number of symbols per stream. If a bitstream is not entirely and exactly consumed, hence reaching exactly its beginning position with _all_ bits consumed, the decoding process is considered faulty. Dictionary Format ----------------- Zstandard is compatible with "raw content" dictionaries, free of any format restriction, except that they must be at least 8 bytes. These dictionaries function as if they were just the `Content` part of a formatted dictionary. But dictionaries created by `zstd --train` follow a format, described here. __Pre-requisites__ : a dictionary has a size, defined either by a buffer limit, or a file size. | `Magic_Number` | `Dictionary_ID` | `Entropy_Tables` | `Content` | | -------------- | --------------- | ---------------- | --------- | __`Magic_Number`__ : 4 bytes ID, value 0xEC30A437, __little-endian__ format __`Dictionary_ID`__ : 4 bytes, stored in __little-endian__ format. `Dictionary_ID` can be any value, except 0 (which means no `Dictionary_ID`). It's used by decoders to check if they use the correct dictionary. _Reserved ranges :_ If the frame is going to be distributed in a private environment, any `Dictionary_ID` can be used. However, for public distribution of compressed frames, the following ranges are reserved and shall not be used : - low range : <= 32767 - high range : >= (2^31) __`Entropy_Tables`__ : following the same format as the tables in compressed blocks. See the relevant [FSE](#fse-table-description) and [Huffman](#huffman-tree-description) sections for how to decode these tables. They are stored in following order : Huffman tables for literals, FSE table for offsets, FSE table for match lengths, and FSE table for literals lengths. These tables populate the Repeat Stats literals mode and Repeat distribution mode for sequence decoding. It's finally followed by 3 offset values, populating recent offsets (instead of using `{1,4,8}`), stored in order, 4-bytes __little-endian__ each, for a total of 12 bytes. Each recent offset must have a value < dictionary size. __`Content`__ : The rest of the dictionary is its content. The content act as a "past" in front of data to compress or decompress, so it can be referenced in sequence commands. As long as the amount of data decoded from this frame is less than or equal to `Window_Size`, sequence commands may specify offsets longer than the total length of decoded output so far to reference back to the dictionary. After the total output has surpassed `Window_Size` however, this is no longer allowed and the dictionary is no longer accessible. [compressed blocks]: #the-format-of-compressed_block Appendix A - Decoding tables for predefined codes ------------------------------------------------- This appendix contains FSE decoding tables for the predefined literal length, match length, and offset codes. The tables have been constructed using the algorithm as given above in chapter "from normalized distribution to decoding tables". The tables here can be used as examples to crosscheck that an implementation build its decoding tables correctly. #### Literal Length Code: | State | Symbol | Number_Of_Bits | Base | | ----- | ------ | -------------- | ---- | | 0 | 0 | 4 | 0 | | 1 | 0 | 4 | 16 | | 2 | 1 | 5 | 32 | | 3 | 3 | 5 | 0 | | 4 | 4 | 5 | 0 | | 5 | 6 | 5 | 0 | | 6 | 7 | 5 | 0 | | 7 | 9 | 5 | 0 | | 8 | 10 | 5 | 0 | | 9 | 12 | 5 | 0 | | 10 | 14 | 6 | 0 | | 11 | 16 | 5 | 0 | | 12 | 18 | 5 | 0 | | 13 | 19 | 5 | 0 | | 14 | 21 | 5 | 0 | | 15 | 22 | 5 | 0 | | 16 | 24 | 5 | 0 | | 17 | 25 | 5 | 32 | | 18 | 26 | 5 | 0 | | 19 | 27 | 6 | 0 | | 20 | 29 | 6 | 0 | | 21 | 31 | 6 | 0 | | 22 | 0 | 4 | 32 | | 23 | 1 | 4 | 0 | | 24 | 2 | 5 | 0 | | 25 | 4 | 5 | 32 | | 26 | 5 | 5 | 0 | | 27 | 7 | 5 | 32 | | 28 | 8 | 5 | 0 | | 29 | 10 | 5 | 32 | | 30 | 11 | 5 | 0 | | 31 | 13 | 6 | 0 | | 32 | 16 | 5 | 32 | | 33 | 17 | 5 | 0 | | 34 | 19 | 5 | 32 | | 35 | 20 | 5 | 0 | | 36 | 22 | 5 | 32 | | 37 | 23 | 5 | 0 | | 38 | 25 | 4 | 0 | | 39 | 25 | 4 | 16 | | 40 | 26 | 5 | 32 | | 41 | 28 | 6 | 0 | | 42 | 30 | 6 | 0 | | 43 | 0 | 4 | 48 | | 44 | 1 | 4 | 16 | | 45 | 2 | 5 | 32 | | 46 | 3 | 5 | 32 | | 47 | 5 | 5 | 32 | | 48 | 6 | 5 | 32 | | 49 | 8 | 5 | 32 | | 50 | 9 | 5 | 32 | | 51 | 11 | 5 | 32 | | 52 | 12 | 5 | 32 | | 53 | 15 | 6 | 0 | | 54 | 17 | 5 | 32 | | 55 | 18 | 5 | 32 | | 56 | 20 | 5 | 32 | | 57 | 21 | 5 | 32 | | 58 | 23 | 5 | 32 | | 59 | 24 | 5 | 32 | | 60 | 35 | 6 | 0 | | 61 | 34 | 6 | 0 | | 62 | 33 | 6 | 0 | | 63 | 32 | 6 | 0 | #### Match Length Code: | State | Symbol | Number_Of_Bits | Base | | ----- | ------ | -------------- | ---- | | 0 | 0 | 6 | 0 | | 1 | 1 | 4 | 0 | | 2 | 2 | 5 | 32 | | 3 | 3 | 5 | 0 | | 4 | 5 | 5 | 0 | | 5 | 6 | 5 | 0 | | 6 | 8 | 5 | 0 | | 7 | 10 | 6 | 0 | | 8 | 13 | 6 | 0 | | 9 | 16 | 6 | 0 | | 10 | 19 | 6 | 0 | | 11 | 22 | 6 | 0 | | 12 | 25 | 6 | 0 | | 13 | 28 | 6 | 0 | | 14 | 31 | 6 | 0 | | 15 | 33 | 6 | 0 | | 16 | 35 | 6 | 0 | | 17 | 37 | 6 | 0 | | 18 | 39 | 6 | 0 | | 19 | 41 | 6 | 0 | | 20 | 43 | 6 | 0 | | 21 | 45 | 6 | 0 | | 22 | 1 | 4 | 16 | | 23 | 2 | 4 | 0 | | 24 | 3 | 5 | 32 | | 25 | 4 | 5 | 0 | | 26 | 6 | 5 | 32 | | 27 | 7 | 5 | 0 | | 28 | 9 | 6 | 0 | | 29 | 12 | 6 | 0 | | 30 | 15 | 6 | 0 | | 31 | 18 | 6 | 0 | | 32 | 21 | 6 | 0 | | 33 | 24 | 6 | 0 | | 34 | 27 | 6 | 0 | | 35 | 30 | 6 | 0 | | 36 | 32 | 6 | 0 | | 37 | 34 | 6 | 0 | | 38 | 36 | 6 | 0 | | 39 | 38 | 6 | 0 | | 40 | 40 | 6 | 0 | | 41 | 42 | 6 | 0 | | 42 | 44 | 6 | 0 | | 43 | 1 | 4 | 32 | | 44 | 1 | 4 | 48 | | 45 | 2 | 4 | 16 | | 46 | 4 | 5 | 32 | | 47 | 5 | 5 | 32 | | 48 | 7 | 5 | 32 | | 49 | 8 | 5 | 32 | | 50 | 11 | 6 | 0 | | 51 | 14 | 6 | 0 | | 52 | 17 | 6 | 0 | | 53 | 20 | 6 | 0 | | 54 | 23 | 6 | 0 | | 55 | 26 | 6 | 0 | | 56 | 29 | 6 | 0 | | 57 | 52 | 6 | 0 | | 58 | 51 | 6 | 0 | | 59 | 50 | 6 | 0 | | 60 | 49 | 6 | 0 | | 61 | 48 | 6 | 0 | | 62 | 47 | 6 | 0 | | 63 | 46 | 6 | 0 | #### Offset Code: | State | Symbol | Number_Of_Bits | Base | | ----- | ------ | -------------- | ---- | | 0 | 0 | 5 | 0 | | 1 | 6 | 4 | 0 | | 2 | 9 | 5 | 0 | | 3 | 15 | 5 | 0 | | 4 | 21 | 5 | 0 | | 5 | 3 | 5 | 0 | | 6 | 7 | 4 | 0 | | 7 | 12 | 5 | 0 | | 8 | 18 | 5 | 0 | | 9 | 23 | 5 | 0 | | 10 | 5 | 5 | 0 | | 11 | 8 | 4 | 0 | | 12 | 14 | 5 | 0 | | 13 | 20 | 5 | 0 | | 14 | 2 | 5 | 0 | | 15 | 7 | 4 | 16 | | 16 | 11 | 5 | 0 | | 17 | 17 | 5 | 0 | | 18 | 22 | 5 | 0 | | 19 | 4 | 5 | 0 | | 20 | 8 | 4 | 16 | | 21 | 13 | 5 | 0 | | 22 | 19 | 5 | 0 | | 23 | 1 | 5 | 0 | | 24 | 6 | 4 | 16 | | 25 | 10 | 5 | 0 | | 26 | 16 | 5 | 0 | | 27 | 28 | 5 | 0 | | 28 | 27 | 5 | 0 | | 29 | 26 | 5 | 0 | | 30 | 25 | 5 | 0 | | 31 | 24 | 5 | 0 | Version changes --------------- - 0.2.6 : fixed an error in huffman example, by Ulrich Kunitz - 0.2.5 : minor typos and clarifications - 0.2.4 : section restructuring, by Sean Purcell - 0.2.3 : clarified several details, by Sean Purcell - 0.2.2 : added predefined codes, by Johannes Rudolph - 0.2.1 : clarify field names, by Przemyslaw Skibinski - 0.2.0 : numerous format adjustments for zstd v0.8+ - 0.1.2 : limit Huffman tree depth to 11 bits - 0.1.1 : reserved dictID ranges - 0.1.0 : initial release Index: head/sys/contrib/zstd/doc/zstd_manual.html =================================================================== --- head/sys/contrib/zstd/doc/zstd_manual.html (revision 330893) +++ head/sys/contrib/zstd/doc/zstd_manual.html (revision 330894) @@ -1,1200 +1,1212 @@ -zstd 1.3.2 Manual +zstd 1.3.3 Manual -

zstd 1.3.2 Manual

+

zstd 1.3.3 Manual

Contents

  1. Introduction
  2. Version
  3. Simple API
  4. Explicit memory management
  5. Simple dictionary API
  6. Bulk processing dictionary API
  7. Streaming
  8. Streaming compression - HowTo
  9. Streaming decompression - HowTo
  10. START OF ADVANCED AND EXPERIMENTAL FUNCTIONS
  11. Advanced types
    12. -
  12. Frame size functions
    13. -
  13. Context memory usage
    14. -
  14. Advanced compression functions
    15. -
  15. Advanced decompression functions
    16. -
  16. Advanced streaming functions
    17. -
  17. Buffer-less and synchronous inner streaming functions
    18. -
  18. Buffer-less streaming compression (synchronous mode)
    19. -
  19. Buffer-less streaming decompression (synchronous mode)
    20. -
  20. New advanced API (experimental)
    21. -
  21. Block level API
    22. +
  22. Custom memory allocation functions
    23. +
  23. Frame size functions
    24. +
  24. Context memory usage
    25. +
  25. Advanced compression functions
    26. +
  26. Advanced decompression functions
    27. +
  27. Advanced streaming functions
    28. +
  28. Buffer-less and synchronous inner streaming functions
    29. +
  29. Buffer-less streaming compression (synchronous mode)
    30. +
  30. Buffer-less streaming decompression (synchronous mode)
    31. +
  31. New advanced API (experimental)
    32. +
  32. Block level API

Introduction

   zstd, short for Zstandard, is a fast lossless compression algorithm,
   targeting real-time compression scenarios at zlib-level and better compression ratios.
   The zstd compression library provides in-memory compression and decompression functions.
   The library supports compression levels from 1 up to ZSTD_maxCLevel() which is currently 22.
   Levels >= 20, labeled `--ultra`, should be used with caution, as they require more memory.
   Compression can be done in:
     - a single step (described as Simple API)
     - a single step, reusing a context (described as Explicit memory management)
     - unbounded multiple steps (described as Streaming compression)
   The compression ratio achievable on small data can be highly improved using a dictionary in:
     - a single step (described as Simple dictionary API)
     - a single step, reusing a dictionary (described as Fast dictionary API)
 
   Advanced experimental functions can be accessed using #define ZSTD_STATIC_LINKING_ONLY before including zstd.h.
   Advanced experimental APIs shall never be used with a dynamic library.
   They are not "stable", their definition may change in the future. Only static linking is allowed.

Version


 
 
unsigned ZSTD_versionNumber(void);   /**< useful to check dll version */
 


 
Simple API

 
 
size_t ZSTD_compress( void* dst, size_t dstCapacity,
                 const void* src, size_t srcSize,
                       int compressionLevel);
 
  Compresses `src` content as a single zstd compressed frame into already allocated `dst`.
   Hint : compression runs faster if `dstCapacity` >=  `ZSTD_compressBound(srcSize)`.
   @return : compressed size written into `dst` (<= `dstCapacity),
             or an error code if it fails (which can be tested using ZSTD_isError()). 
 


 
 
size_t ZSTD_decompress( void* dst, size_t dstCapacity,
                   const void* src, size_t compressedSize);
 
  `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames.
   `dstCapacity` is an upper bound of originalSize to regenerate.
   If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data.
   @return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
             or an errorCode if it fails (which can be tested using ZSTD_isError()). 
 


 
 
#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1)
 #define ZSTD_CONTENTSIZE_ERROR   (0ULL - 2)
 unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize);
 
  `src` should point to the start of a ZSTD encoded frame.
   `srcSize` must be at least as large as the frame header.
             hint : any size >= `ZSTD_frameHeaderSize_max` is large enough.
   @return : - decompressed size of the frame in `src`, if known
             - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
             - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small)
    note 1 : a 0 return value means the frame is valid but "empty".
    note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode.
             When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.
             In which case, it's necessary to use streaming mode to decompress data.
             Optionally, application can rely on some implicit limit,
             as ZSTD_decompress() only needs an upper bound of decompressed size.
             (For example, data could be necessarily cut into blocks <= 16 KB).
    note 3 : decompressed size is always present when compression is done with ZSTD_compress()
    note 4 : decompressed size can be very large (64-bits value),
             potentially larger than what local system can handle as a single memory segment.
             In which case, it's necessary to use streaming mode to decompress data.
    note 5 : If source is untrusted, decompressed size could be wrong or intentionally modified.
             Always ensure return value fits within application's authorized limits.
             Each application can set its own limits.
    note 6 : This function replaces ZSTD_getDecompressedSize() 
 


 
 
unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize);
 
  NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize().
   Both functions work the same way,
   but ZSTD_getDecompressedSize() blends
   "empty", "unknown" and "error" results in the same return value (0),
   while ZSTD_getFrameContentSize() distinguishes them.
 
   'src' is the start of a zstd compressed frame.
   @return : content size to be decompressed, as a 64-bits value _if known and not empty_, 0 otherwise. 
 


 
-
Helper functions
#define ZSTD_COMPRESSBOUND(srcSize)   ((srcSize) + ((srcSize)>>8) + (((srcSize) < 128 KB) ? ((128 KB - (srcSize)) >> 11) /* margin, from 64 to 0 */ : 0))  /* this formula ensures that bound(A) + bound(B) <= bound(A+B) as long as A and B >= 128 KB */
+
Helper functions
#define ZSTD_COMPRESSBOUND(srcSize)   ((srcSize) + ((srcSize)>>8) + (((srcSize) < (128<<10)) ? (((128<<10) - (srcSize)) >> 11) /* margin, from 64 to 0 */ : 0))  /* this formula ensures that bound(A) + bound(B) <= bound(A+B) as long as A and B >= 128 KB */
 size_t      ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case scenario */
 unsigned    ZSTD_isError(size_t code);          /*!< tells if a `size_t` function result is an error code */
 const char* ZSTD_getErrorName(size_t code);     /*!< provides readable string from an error code */
 int         ZSTD_maxCLevel(void);               /*!< maximum compression level available */
 


 
Explicit memory management

 
 
Compression context
  When compressing many times,
   it is recommended to allocate a context just once, and re-use it for each successive compression operation.
   This will make workload friendlier for system's memory.
   Use one context per thread for parallel execution in multi-threaded environments. 
 
typedef struct ZSTD_CCtx_s ZSTD_CCtx;
 ZSTD_CCtx* ZSTD_createCCtx(void);
 size_t     ZSTD_freeCCtx(ZSTD_CCtx* cctx);
 


 
size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx,
                          void* dst, size_t dstCapacity,
                    const void* src, size_t srcSize,
                          int compressionLevel);
 
  Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()). 
 


 
 
Decompression context
  When decompressing many times,
   it is recommended to allocate a context only once,
   and re-use it for each successive compression operation.
   This will make workload friendlier for system's memory.
   Use one context per thread for parallel execution. 
 
typedef struct ZSTD_DCtx_s ZSTD_DCtx;
 ZSTD_DCtx* ZSTD_createDCtx(void);
 size_t     ZSTD_freeDCtx(ZSTD_DCtx* dctx);
 


 
size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx,
                            void* dst, size_t dstCapacity,
                      const void* src, size_t srcSize);
 
  Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()) 
 


 
 
Simple dictionary API

 
 
size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,
                                void* dst, size_t dstCapacity,
                          const void* src, size_t srcSize,
                          const void* dict,size_t dictSize,
                                int compressionLevel);
 
  Compression using a predefined Dictionary (see dictBuilder/zdict.h).
   Note : This function loads the dictionary, resulting in significant startup delay.
   Note : When `dict == NULL || dictSize < 8` no dictionary is used. 
 


 
 
size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
                                  void* dst, size_t dstCapacity,
                            const void* src, size_t srcSize,
                            const void* dict,size_t dictSize);
 
  Decompression using a predefined Dictionary (see dictBuilder/zdict.h).
   Dictionary must be identical to the one used during compression.
   Note : This function loads the dictionary, resulting in significant startup delay.
   Note : When `dict == NULL || dictSize < 8` no dictionary is used. 
 


 
 
Bulk processing dictionary API

 
 
ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize,
                              int compressionLevel);
 
  When compressing multiple messages / blocks with the same dictionary, it's recommended to load it just once.
   ZSTD_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.
   ZSTD_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only.
   `dictBuffer` can be released after ZSTD_CDict creation, since its content is copied within CDict 
 


 
 
size_t      ZSTD_freeCDict(ZSTD_CDict* CDict);
 
  Function frees memory allocated by ZSTD_createCDict(). 
 


 
 
size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
                                 void* dst, size_t dstCapacity,
                           const void* src, size_t srcSize,
                           const ZSTD_CDict* cdict);
 
  Compression using a digested Dictionary.
   Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times.
   Note that compression level is decided during dictionary creation.
   Frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no) 
 


 
 
ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize);
 
  Create a digested dictionary, ready to start decompression operation without startup delay.
   dictBuffer can be released after DDict creation, as its content is copied inside DDict 
 


 
 
size_t      ZSTD_freeDDict(ZSTD_DDict* ddict);
 
  Function frees memory allocated with ZSTD_createDDict() 
 


 
 
size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
                                   void* dst, size_t dstCapacity,
                             const void* src, size_t srcSize,
                             const ZSTD_DDict* ddict);
 
  Decompression using a digested Dictionary.
   Faster startup than ZSTD_decompress_usingDict(), recommended when same dictionary is used multiple times. 
 


 
 
Streaming

 
 
typedef struct ZSTD_inBuffer_s {
   const void* src;    /**< start of input buffer */
   size_t size;        /**< size of input buffer */
   size_t pos;         /**< position where reading stopped. Will be updated. Necessarily 0 <= pos <= size */
 } ZSTD_inBuffer;
 


 
typedef struct ZSTD_outBuffer_s {
   void*  dst;         /**< start of output buffer */
   size_t size;        /**< size of output buffer */
   size_t pos;         /**< position where writing stopped. Will be updated. Necessarily 0 <= pos <= size */
 } ZSTD_outBuffer;
 


 
Streaming compression - HowTo
   A ZSTD_CStream object is required to track streaming operation.
   Use ZSTD_createCStream() and ZSTD_freeCStream() to create/release resources.
   ZSTD_CStream objects can be reused multiple times on consecutive compression operations.
   It is recommended to re-use ZSTD_CStream in situations where many streaming operations will be achieved consecutively,
   since it will play nicer with system's memory, by re-using already allocated memory.
   Use one separate ZSTD_CStream per thread for parallel execution.
 
   Start a new compression by initializing ZSTD_CStream.
   Use ZSTD_initCStream() to start a new compression operation.
   Use ZSTD_initCStream_usingDict() or ZSTD_initCStream_usingCDict() for a compression which requires a dictionary (experimental section)
 
   Use ZSTD_compressStream() repetitively to consume input stream.
   The function will automatically update both `pos` fields.
   Note that it may not consume the entire input, in which case `pos < size`,
   and it's up to the caller to present again remaining data.
   @return : a size hint, preferred nb of bytes to use as input for next function call
             or an error code, which can be tested using ZSTD_isError().
             Note 1 : it's just a hint, to help latency a little, any other value will work fine.
             Note 2 : size hint is guaranteed to be <= ZSTD_CStreamInSize()
 
   At any moment, it's possible to flush whatever data remains within internal buffer, using ZSTD_flushStream().
   `output->pos` will be updated.
   Note that some content might still be left within internal buffer if `output->size` is too small.
   @return : nb of bytes still present within internal buffer (0 if it's empty)
             or an error code, which can be tested using ZSTD_isError().
 
   ZSTD_endStream() instructs to finish a frame.
   It will perform a flush and write frame epilogue.
   The epilogue is required for decoders to consider a frame completed.
   ZSTD_endStream() may not be able to flush full data if `output->size` is too small.
   In which case, call again ZSTD_endStream() to complete the flush.
   @return : 0 if frame fully completed and fully flushed,
              or >0 if some data is still present within internal buffer
                   (value is minimum size estimation for remaining data to flush, but it could be more)
             or an error code, which can be tested using ZSTD_isError().
 
  
 

 
 
typedef ZSTD_CCtx ZSTD_CStream;  /**< CCtx and CStream are now effectively same object (>= v1.3.0) */
 


 
ZSTD_CStream management functions
ZSTD_CStream* ZSTD_createCStream(void);
 size_t ZSTD_freeCStream(ZSTD_CStream* zcs);
 


 
Streaming compression functions
size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel);
 size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
 size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output);
 size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output);
 


 
size_t ZSTD_CStreamInSize(void);    /**< recommended size for input buffer */
 


 
size_t ZSTD_CStreamOutSize(void);   /**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block in all circumstances. */
 


 
Streaming decompression - HowTo
   A ZSTD_DStream object is required to track streaming operations.
   Use ZSTD_createDStream() and ZSTD_freeDStream() to create/release resources.
   ZSTD_DStream objects can be re-used multiple times.
 
   Use ZSTD_initDStream() to start a new decompression operation,
    or ZSTD_initDStream_usingDict() if decompression requires a dictionary.
    @return : recommended first input size
 
   Use ZSTD_decompressStream() repetitively to consume your input.
   The function will update both `pos` fields.
   If `input.pos < input.size`, some input has not been consumed.
   It's up to the caller to present again remaining data.
   If `output.pos < output.size`, decoder has flushed everything it could.
   @return : 0 when a frame is completely decoded and fully flushed,
             an error code, which can be tested using ZSTD_isError(),
             any other value > 0, which means there is still some decoding to do to complete current frame.
             The return value is a suggested next input size (a hint to improve latency) that will never load more than the current frame.
  
 

 
 
typedef ZSTD_DCtx ZSTD_DStream;  /**< DCtx and DStream are now effectively same object (>= v1.3.0) */
 


 
ZSTD_DStream management functions
ZSTD_DStream* ZSTD_createDStream(void);
 size_t ZSTD_freeDStream(ZSTD_DStream* zds);
 


 
Streaming decompression functions
size_t ZSTD_initDStream(ZSTD_DStream* zds);
 size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
 


 
size_t ZSTD_DStreamInSize(void);    /*!< recommended size for input buffer */
 


 
size_t ZSTD_DStreamOutSize(void);   /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */
 


 
START OF ADVANCED AND EXPERIMENTAL FUNCTIONS
 The definitions in this section are considered experimental.
  They should never be used with a dynamic library, as prototypes may change in the future.
  They are provided for advanced scenarios.
  Use them only in association with static linking.
  
 

 
 
Advanced types

 
 
typedef enum { ZSTD_fast=1, ZSTD_dfast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2,
                ZSTD_btlazy2, ZSTD_btopt, ZSTD_btultra } ZSTD_strategy;   /* from faster to stronger */
 


 
typedef struct {
     unsigned windowLog;      /**< largest match distance : larger == more compression, more memory needed during decompression */
     unsigned chainLog;       /**< fully searched segment : larger == more compression, slower, more memory (useless for fast) */
     unsigned hashLog;        /**< dispatch table : larger == faster, more memory */
     unsigned searchLog;      /**< nb of searches : larger == more compression, slower */
     unsigned searchLength;   /**< match length searched : larger == faster decompression, sometimes less compression */
     unsigned targetLength;   /**< acceptable match size for optimal parser (only) : larger == more compression, slower */
     ZSTD_strategy strategy;
 } ZSTD_compressionParameters;
 


 
typedef struct {
     unsigned contentSizeFlag; /**< 1: content size will be in frame header (when known) */
     unsigned checksumFlag;    /**< 1: generate a 32-bits checksum at end of frame, for error detection */
     unsigned noDictIDFlag;    /**< 1: no dictID will be saved into frame header (if dictionary compression) */
 } ZSTD_frameParameters;
 


 
typedef struct {
     ZSTD_compressionParameters cParams;
     ZSTD_frameParameters fParams;
 } ZSTD_parameters;
 


-
Custom memory allocation functions
typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size);
-typedef void  (*ZSTD_freeFunction) (void* opaque, void* address);
-typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem;
-/* use this constant to defer to stdlib's functions */
-static const ZSTD_customMem ZSTD_defaultCMem = { NULL, NULL, NULL };
-


-
Frame size functions

+
Custom memory allocation functions

 
+
typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem;
+


+
Frame size functions

+
 
size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize);
 
  `src` should point to the start of a ZSTD encoded frame or skippable frame
-  `srcSize` must be at least as large as the frame
+  `srcSize` must be >= first frame size
   @return : the compressed size of the first frame starting at `src`,
             suitable to pass to `ZSTD_decompress` or similar,
             or an error code if input is invalid 
 


 
 
unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize);
 
  `src` should point the start of a series of ZSTD encoded and/or skippable frames
   `srcSize` must be the _exact_ size of this series
        (i.e. there should be a frame boundary exactly at `srcSize` bytes after `src`)
   @return : - decompressed size of all data in all successive frames
             - if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN
             - if an error occurred: ZSTD_CONTENTSIZE_ERROR
 
    note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode.
             When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.
             In which case, it's necessary to use streaming mode to decompress data.
    note 2 : decompressed size is always present when compression is done with ZSTD_compress()
    note 3 : decompressed size can be very large (64-bits value),
             potentially larger than what local system can handle as a single memory segment.
             In which case, it's necessary to use streaming mode to decompress data.
    note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified.
             Always ensure result fits within application's authorized limits.
             Each application can set its own limits.
    note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to
             read each contained frame header.  This is fast as most of the data is skipped,
             however it does mean that all frame data must be present and valid. 
 


 
 
size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize);
 
   `src` should point to the start of a ZSTD frame
    `srcSize` must be >= ZSTD_frameHeaderSize_prefix.
    @return : size of the Frame Header 
 


 
-
Context memory usage

+
Context memory usage

 
 
size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx);
 size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx);
 size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs);
 size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds);
 size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict);
 size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
 
  These functions give the current memory usage of selected object.
   Object memory usage can evolve when re-used multiple times. 
 


 
 
size_t ZSTD_estimateCCtxSize(int compressionLevel);
 size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams);
 size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params);
 size_t ZSTD_estimateDCtxSize(void);
 
  These functions make it possible to estimate memory usage
   of a future {D,C}Ctx, before its creation.
   ZSTD_estimateCCtxSize() will provide a budget large enough for any compression level up to selected one.
   It will also consider src size to be arbitrarily "large", which is worst case.
   If srcSize is known to always be small, ZSTD_estimateCCtxSize_usingCParams() can provide a tighter estimation.
   ZSTD_estimateCCtxSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
   ZSTD_estimateCCtxSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_p_nbThreads is > 1.
   Note : CCtx estimation is only correct for single-threaded compression 
 


 
 
size_t ZSTD_estimateCStreamSize(int compressionLevel);
 size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams);
 size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params);
 size_t ZSTD_estimateDStreamSize(size_t windowSize);
 size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize);
 
  ZSTD_estimateCStreamSize() will provide a budget large enough for any compression level up to selected one.
   It will also consider src size to be arbitrarily "large", which is worst case.
   If srcSize is known to always be small, ZSTD_estimateCStreamSize_usingCParams() can provide a tighter estimation.
   ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
   ZSTD_estimateCStreamSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_p_nbThreads is set to a value > 1.
   Note : CStream estimation is only correct for single-threaded compression.
   ZSTD_DStream memory budget depends on window Size.
   This information can be passed manually, using ZSTD_estimateDStreamSize,
   or deducted from a valid frame Header, using ZSTD_estimateDStreamSize_fromFrame();
   Note : if streaming is init with function ZSTD_init?Stream_usingDict(),
          an internal ?Dict will be created, which additional size is not estimated here.
          In this case, get total size by adding ZSTD_estimate?DictSize 
 


 
 
typedef enum {
     ZSTD_dlm_byCopy = 0,     /**< Copy dictionary content internally */
     ZSTD_dlm_byRef,          /**< Reference dictionary content -- the dictionary buffer must outlive its users. */
 } ZSTD_dictLoadMethod_e;
 


 
size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel);
 size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod);
 size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod);
 
  ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict().
   ZSTD_estimateCStreamSize_advanced_usingCParams() makes it possible to control precisely compression parameters, like ZSTD_createCDict_advanced().
   Note : dictionary created by reference using ZSTD_dlm_byRef are smaller
  
 


 
-
Advanced compression functions

+
Advanced compression functions

 
 
ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
 
  Create a ZSTD compression context using external alloc and free functions 
 


 
 
ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize);
 
  workspace: The memory area to emplace the context into.
              Provided pointer must 8-bytes aligned.
              It must outlive context usage.
   workspaceSize: Use ZSTD_estimateCCtxSize() or ZSTD_estimateCStreamSize()
                  to determine how large workspace must be to support scenario.
- @return : pointer to ZSTD_CCtx*, or NULL if error (size too small)
+ @return : pointer to ZSTD_CCtx* (same address as workspace, but different type),
+           or NULL if error (typically size too small)
   Note : zstd will never resize nor malloc() when using a static cctx.
          If it needs more memory than available, it will simply error out.
   Note 2 : there is no corresponding "free" function.
            Since workspace was allocated externally, it must be freed externally too.
   Limitation 1 : currently not compatible with internal CDict creation, such as
                  ZSTD_CCtx_loadDictionary() or ZSTD_initCStream_usingDict().
   Limitation 2 : currently not compatible with multi-threading
  
 


 
 
ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel);
 
  Create a digested dictionary for compression
   Dictionary content is simply referenced, and therefore stays in dictBuffer.
   It is important that dictBuffer outlives CDict, it must remain read accessible throughout the lifetime of CDict 
 


 
 
typedef enum { ZSTD_dm_auto=0,        /* dictionary is "full" if it starts with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */
                ZSTD_dm_rawContent,    /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */
                ZSTD_dm_fullDict       /* refuses to load a dictionary if it does not respect Zstandard's specification */
 } ZSTD_dictMode_e;
 


 
ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize,
                                       ZSTD_dictLoadMethod_e dictLoadMethod,
                                       ZSTD_dictMode_e dictMode,
                                       ZSTD_compressionParameters cParams,
                                       ZSTD_customMem customMem);
 
  Create a ZSTD_CDict using external alloc and free, and customized compression parameters 
 


 
 
ZSTD_CDict* ZSTD_initStaticCDict(
                 void* workspace, size_t workspaceSize,
           const void* dict, size_t dictSize,
                 ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictMode_e dictMode,
                 ZSTD_compressionParameters cParams);
 
  Generate a digested dictionary in provided memory area.
   workspace: The memory area to emplace the dictionary into.
              Provided pointer must 8-bytes aligned.
              It must outlive dictionary usage.
   workspaceSize: Use ZSTD_estimateCDictSize()
                  to determine how large workspace must be.
   cParams : use ZSTD_getCParams() to transform a compression level
             into its relevants cParams.
- @return : pointer to ZSTD_CDict*, or NULL if error (size too small)
+ @return : pointer to ZSTD_CDict* (same address as workspace, but different type),
+           or NULL if error (typically, size too small).
   Note : there is no corresponding "free" function.
          Since workspace was allocated externally, it must be freed externally.
  
 


 
 
ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize);
 
   @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize.
    `estimatedSrcSize` value is optional, select 0 if not known 
 


 
 
ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize);
 
   same as ZSTD_getCParams(), but @return a full `ZSTD_parameters` object instead of sub-component `ZSTD_compressionParameters`.
-   All fields of `ZSTD_frameParameters` are set to default (0) 
+   All fields of `ZSTD_frameParameters` are set to default : contentSize=1, checksum=0, noDictID=0 
 


 
 
size_t ZSTD_checkCParams(ZSTD_compressionParameters params);
 
   Ensure param values remain within authorized range 
 


 
 
ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize);
 
  optimize params for a given `srcSize` and `dictSize`.
   both values are optional, select `0` if unknown. 
 


 
 
size_t ZSTD_compress_advanced (ZSTD_CCtx* cctx,
                       void* dst, size_t dstCapacity,
                 const void* src, size_t srcSize,
                 const void* dict,size_t dictSize,
                       ZSTD_parameters params);
 
   Same as ZSTD_compress_usingDict(), with fine-tune control over each compression parameter 
 


 
 
size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx,
                       void* dst, size_t dstCapacity,
                 const void* src, size_t srcSize,
                 const ZSTD_CDict* cdict, ZSTD_frameParameters fParams);
 
   Same as ZSTD_compress_usingCDict(), with fine-tune control over frame parameters 
 


 
-
Advanced decompression functions

+
Advanced decompression functions

 
 
unsigned ZSTD_isFrame(const void* buffer, size_t size);
 
  Tells if the content of `buffer` starts with a valid Frame Identifier.
   Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0.
   Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled.
   Note 3 : Skippable Frame Identifiers are considered valid. 
 


 
 
ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem);
 
  Create a ZSTD decompression context using external alloc and free functions 
 


 
 
ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize);
 
  workspace: The memory area to emplace the context into.
              Provided pointer must 8-bytes aligned.
              It must outlive context usage.
   workspaceSize: Use ZSTD_estimateDCtxSize() or ZSTD_estimateDStreamSize()
                  to determine how large workspace must be to support scenario.
- @return : pointer to ZSTD_DCtx*, or NULL if error (size too small)
+ @return : pointer to ZSTD_DCtx* (same address as workspace, but different type),
+           or NULL if error (typically size too small)
   Note : zstd will never resize nor malloc() when using a static dctx.
          If it needs more memory than available, it will simply error out.
   Note 2 : static dctx is incompatible with legacy support
   Note 3 : there is no corresponding "free" function.
            Since workspace was allocated externally, it must be freed externally.
   Limitation : currently not compatible with internal DDict creation,
                such as ZSTD_initDStream_usingDict().
  
 


 
 
ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize);
 
  Create a digested dictionary, ready to start decompression operation without startup delay.
   Dictionary content is referenced, and therefore stays in dictBuffer.
   It is important that dictBuffer outlives DDict,
   it must remain read accessible throughout the lifetime of DDict 
 


 
 
ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
                                       ZSTD_dictLoadMethod_e dictLoadMethod,
                                       ZSTD_customMem customMem);
 
  Create a ZSTD_DDict using external alloc and free, optionally by reference 
 


 
 
ZSTD_DDict* ZSTD_initStaticDDict(void* workspace, size_t workspaceSize,
                                  const void* dict, size_t dictSize,
                                  ZSTD_dictLoadMethod_e dictLoadMethod);
 
  Generate a digested dictionary in provided memory area.
   workspace: The memory area to emplace the dictionary into.
              Provided pointer must 8-bytes aligned.
              It must outlive dictionary usage.
   workspaceSize: Use ZSTD_estimateDDictSize()
                  to determine how large workspace must be.
  @return : pointer to ZSTD_DDict*, or NULL if error (size too small)
   Note : there is no corresponding "free" function.
          Since workspace was allocated externally, it must be freed externally.
  
 


 
 
unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize);
 
  Provides the dictID stored within dictionary.
   if @return == 0, the dictionary is not conformant with Zstandard specification.
   It can still be loaded, but as a content-only dictionary. 
 


 
 
unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict);
 
  Provides the dictID of the dictionary loaded into `ddict`.
   If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
   Non-conformant dictionaries can still be loaded, but as content-only dictionaries. 
 


 
 
unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
 
  Provides the dictID required to decompressed the frame stored within `src`.
   If @return == 0, the dictID could not be decoded.
   This could for one of the following reasons :
   - The frame does not require a dictionary to be decoded (most common case).
   - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden information.
     Note : this use case also happens when using a non-conformant dictionary.
   - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`).
   - This is not a Zstandard frame.
   When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code. 
 


 
-
Advanced streaming functions

+
Advanced streaming functions

 
 
Advanced Streaming compression functions
ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem);
 ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize);    /**< same as ZSTD_initStaticCCtx() */
-size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize);   /**< pledgedSrcSize must be correct, a size of 0 means unknown.  for a frame size of 0 use initCStream_advanced */
+size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize);   /**< pledgedSrcSize must be correct. If it is not known at init time, use ZSTD_CONTENTSIZE_UNKNOWN. Note that, for compatibility with older programs, "0" also disables frame content size field. It may be enabled in the future. */
 size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); /**< creates of an internal CDict (incompatible with static CCtx), except if dict == NULL or dictSize < 8, in which case no dict is used. Note: dict is loaded with ZSTD_dm_auto (treated as a full zstd dictionary if it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy.*/
 size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize,
-                                             ZSTD_parameters params, unsigned long long pledgedSrcSize);  /**< pledgedSrcSize is optional and can be 0 (meaning unknown). note: if the contentSizeFlag is set, pledgedSrcSize == 0 means the source size is actually 0. dict is loaded with ZSTD_dm_auto and ZSTD_dlm_byCopy. */
+                                             ZSTD_parameters params, unsigned long long pledgedSrcSize);  /**< pledgedSrcSize must be correct. If srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN. dict is loaded with ZSTD_dm_auto and ZSTD_dlm_byCopy. */
 size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict);  /**< note : cdict will just be referenced, and must outlive compression session */
-size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict* cdict, ZSTD_frameParameters fParams, unsigned long long pledgedSrcSize);  /**< same as ZSTD_initCStream_usingCDict(), with control over frame parameters */
+size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict* cdict, ZSTD_frameParameters fParams, unsigned long long pledgedSrcSize);  /**< same as ZSTD_initCStream_usingCDict(), with control over frame parameters. pledgedSrcSize must be correct. If srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN. */
 


 
size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize);
 
  start a new compression job, using same parameters from previous job.
   This is typically useful to skip dictionary loading stage, since it will re-use it in-place..
   Note that zcs must be init at least once before using ZSTD_resetCStream().
-  pledgedSrcSize==0 means "srcSize unknown".
+  If pledgedSrcSize is not known at reset time, use macro ZSTD_CONTENTSIZE_UNKNOWN.
   If pledgedSrcSize > 0, its value must be correct, as it will be written in header, and controlled at the end.
-  @return : 0, or an error code (which can be tested using ZSTD_isError()) 
+  For the time being, pledgedSrcSize==0 is interpreted as "srcSize unknown" for compatibility with older programs,
+  but it may change to mean "empty" in some future version, so prefer using macro ZSTD_CONTENTSIZE_UNKNOWN.
+ @return : 0, or an error code (which can be tested using ZSTD_isError()) 
 


 
 
Advanced Streaming decompression functions
ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem);
 ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize);    /**< same as ZSTD_initStaticDCtx() */
 typedef enum { DStream_p_maxWindowSize } ZSTD_DStreamParameter_e;
 size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds, ZSTD_DStreamParameter_e paramType, unsigned paramValue);   /* obsolete : this API will be removed in a future version */
 size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); /**< note: no dictionary will be used if dict == NULL or dictSize < 8 */
 size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict);  /**< note : ddict is referenced, it must outlive decompression session */
 size_t ZSTD_resetDStream(ZSTD_DStream* zds);  /**< re-use decompression parameters from previous init; saves dictionary loading */
 


-
Buffer-less and synchronous inner streaming functions
+
Buffer-less and synchronous inner streaming functions
   This is an advanced API, giving full control over buffer management, for users which need direct control over memory.
   But it's also a complex one, with several restrictions, documented below.
   Prefer normal streaming API for an easier experience.
  
 

 
-
Buffer-less streaming compression (synchronous mode)
+
Buffer-less streaming compression (synchronous mode)
   A ZSTD_CCtx object is required to track streaming operations.
   Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource.
   ZSTD_CCtx object can be re-used multiple times within successive compression operations.
 
   Start by initializing a context.
   Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary compression,
   or ZSTD_compressBegin_advanced(), for finer parameter control.
   It's also possible to duplicate a reference context which has already been initialized, using ZSTD_copyCCtx()
 
   Then, consume your input using ZSTD_compressContinue().
   There are some important considerations to keep in mind when using this advanced function :
   - ZSTD_compressContinue() has no internal buffer. It uses externally provided buffers only.
   - Interface is synchronous : input is consumed entirely and produces 1+ compressed blocks.
   - Caller must ensure there is enough space in `dst` to store compressed data under worst case scenario.
     Worst case evaluation is provided by ZSTD_compressBound().
     ZSTD_compressContinue() doesn't guarantee recover after a failed compression.
   - ZSTD_compressContinue() presumes prior input ***is still accessible and unmodified*** (up to maximum distance size, see WindowLog).
     It remembers all previous contiguous blocks, plus one separated memory segment (which can itself consists of multiple contiguous blocks)
   - ZSTD_compressContinue() detects that prior input has been overwritten when `src` buffer overlaps.
     In which case, it will "discard" the relevant memory section from its history.
 
   Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum.
   It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame.
   Without last block mark, frames are considered unfinished (hence corrupted) by compliant decoders.
 
   `ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress again.
 

 
 
Buffer-less streaming compression functions
size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel);
 size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel);
-size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize is optional and can be 0 (meaning unknown). note: if the contentSizeFlag is set, pledgedSrcSize == 0 means the source size is actually 0 */
+size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize : If srcSize is not known at init time, use ZSTD_CONTENTSIZE_UNKNOWN */
 size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); /**< note: fails if cdict==NULL */
-size_t ZSTD_compressBegin_usingCDict_advanced(ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict, ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize);   /* compression parameters are already set within cdict. pledgedSrcSize=0 means null-size */
-size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); /**<  note: if pledgedSrcSize can be 0, indicating unknown size.  if it is non-zero, it must be accurate.  for 0 size frames, use compressBegin_advanced */
+size_t ZSTD_compressBegin_usingCDict_advanced(ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict, ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize);   /* compression parameters are already set within cdict. pledgedSrcSize must be correct. If srcSize is not known, use macro ZSTD_CONTENTSIZE_UNKNOWN */
+size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); /**<  note: if pledgedSrcSize is not known, use ZSTD_CONTENTSIZE_UNKNOWN */
 


-
Buffer-less streaming decompression (synchronous mode)
+
Buffer-less streaming decompression (synchronous mode)
   A ZSTD_DCtx object is required to track streaming operations.
   Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it.
   A ZSTD_DCtx object can be re-used multiple times.
 
   First typical operation is to retrieve frame parameters, using ZSTD_getFrameHeader().
   Frame header is extracted from the beginning of compressed frame, so providing only the frame's beginning is enough.
   Data fragment must be large enough to ensure successful decoding.
  `ZSTD_frameHeaderSize_max` bytes is guaranteed to always be large enough.
   @result : 0 : successful decoding, the `ZSTD_frameHeader` structure is correctly filled.
            >0 : `srcSize` is too small, please provide at least @result bytes on next attempt.
            errorCode, which can be tested using ZSTD_isError().
 
   It fills a ZSTD_frameHeader structure with important information to correctly decode the frame,
   such as the dictionary ID, content size, or maximum back-reference distance (`windowSize`).
   Note that these values could be wrong, either because of data corruption, or because a 3rd party deliberately spoofs false information.
   As a consequence, check that values remain within valid application range.
   For example, do not allocate memory blindly, check that `windowSize` is within expectation.
   Each application can set its own limits, depending on local restrictions.
   For extended interoperability, it is recommended to support `windowSize` of at least 8 MB.
 
   ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize` bytes.
   ZSTD_decompressContinue() is very sensitive to contiguity,
   if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place,
   or that previous contiguous segment is large enough to properly handle maximum back-reference distance.
   There are multiple ways to guarantee this condition.
 
   The most memory efficient way is to use a round buffer of sufficient size.
   Sufficient size is determined by invoking ZSTD_decodingBufferSize_min(),
   which can @return an error code if required value is too large for current system (in 32-bits mode).
   In a round buffer methodology, ZSTD_decompressContinue() decompresses each block next to previous one,
   up to the moment there is not enough room left in the buffer to guarantee decoding another full block,
   which maximum size is provided in `ZSTD_frameHeader` structure, field `blockSizeMax`.
   At which point, decoding can resume from the beginning of the buffer.
   Note that already decoded data stored in the buffer should be flushed before being overwritten.
 
   There are alternatives possible, for example using two or more buffers of size `windowSize` each, though they consume more memory.
 
   Finally, if you control the compression process, you can also ignore all buffer size rules,
   as long as the encoder and decoder progress in "lock-step",
   aka use exactly the same buffer sizes, break contiguity at the same place, etc.
 
   Once buffers are setup, start decompression, with ZSTD_decompressBegin().
   If decompression requires a dictionary, use ZSTD_decompressBegin_usingDict() or ZSTD_decompressBegin_usingDDict().
 
   Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively.
   ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize' to ZSTD_decompressContinue().
   ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will fail.
 
  @result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity).
   It can be zero : it just means ZSTD_decompressContinue() has decoded some metadata item.
   It can also be an error code, which can be tested with ZSTD_isError().
 
   A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
   Context can then be reset to start a new decompression.
 
   Note : it's possible to know if next input to present is a header or a block, using ZSTD_nextInputType().
   This information is not required to properly decode a frame.
 
   == Special case : skippable frames 
 
   Skippable frames allow integration of user-defined data into a flow of concatenated frames.
   Skippable frames will be ignored (skipped) by decompressor.
   The format of skippable frames is as follows :
   a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F
   b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits
   c) Frame Content - any content (User Data) of length equal to Frame Size
   For skippable frames ZSTD_getFrameHeader() returns zfhPtr->frameType==ZSTD_skippableFrame.
   For skippable frames ZSTD_decompressContinue() always returns 0 : it only skips the content.
 

 
 
Buffer-less streaming decompression functions
typedef enum { ZSTD_frame, ZSTD_skippableFrame } ZSTD_frameType_e;
 typedef struct {
     unsigned long long frameContentSize; /* if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty" */
     unsigned long long windowSize;       /* can be very large, up to <= frameContentSize */
     unsigned blockSizeMax;
     ZSTD_frameType_e frameType;          /* if == ZSTD_skippableFrame, frameContentSize is the size of skippable content */
     unsigned headerSize;
     unsigned dictID;
     unsigned checksumFlag;
 } ZSTD_frameHeader;
 size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize);   /**< doesn't consume input */
 size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize);  /**< when frame content size is not known, pass in frameContentSize == ZSTD_CONTENTSIZE_UNKNOWN */
 


 
typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e;
 


-
New advanced API (experimental)

+
New advanced API (experimental)

 
 
typedef enum {
     /* Question : should we have a format ZSTD_f_auto ?
      * For the time being, it would mean exactly the same as ZSTD_f_zstd1.
      * But, in the future, should several formats be supported,
      * on the compression side, it would mean "default format".
      * On the decompression side, it would mean "multi format",
      * and ZSTD_f_zstd1 could be reserved to mean "accept *only* zstd frames".
      * Since meaning is a little different, another option could be to define different enums for compression and decompression.
      * This question could be kept for later, when there are actually multiple formats to support,
      * but there is also the question of pinning enum values, and pinning value `0` is especially important */
     ZSTD_f_zstd1 = 0,        /* zstd frame format, specified in zstd_compression_format.md (default) */
     ZSTD_f_zstd1_magicless,  /* Variant of zstd frame format, without initial 4-bytes magic number.
                               * Useful to save 4 bytes per generated frame.
                               * Decoder cannot recognise automatically this format, requiring instructions. */
 } ZSTD_format_e;
 


 
typedef enum {
     /* compression format */
     ZSTD_p_format = 10,      /* See ZSTD_format_e enum definition.
                               * Cast selected format as unsigned for ZSTD_CCtx_setParameter() compatibility. */
 
     /* compression parameters */
     ZSTD_p_compressionLevel=100, /* Update all compression parameters according to pre-defined cLevel table
                               * Default level is ZSTD_CLEVEL_DEFAULT==3.
                               * Special: value 0 means "do not change cLevel". */
     ZSTD_p_windowLog,        /* Maximum allowed back-reference distance, expressed as power of 2.
                               * Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX.
                               * Special: value 0 means "do not change windowLog".
                               * Note: Using a window size greater than ZSTD_MAXWINDOWSIZE_DEFAULT (default: 2^27)
                               * requires setting the maximum window size at least as large during decompression. */
     ZSTD_p_hashLog,          /* Size of the probe table, as a power of 2.
                               * Resulting table size is (1 << (hashLog+2)).
                               * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX.
                               * Larger tables improve compression ratio of strategies <= dFast,
                               * and improve speed of strategies > dFast.
                               * Special: value 0 means "do not change hashLog". */
     ZSTD_p_chainLog,         /* Size of the full-search table, as a power of 2.
                               * Resulting table size is (1 << (chainLog+2)).
                               * Larger tables result in better and slower compression.
                               * This parameter is useless when using "fast" strategy.
                               * Special: value 0 means "do not change chainLog". */
     ZSTD_p_searchLog,        /* Number of search attempts, as a power of 2.
                               * More attempts result in better and slower compression.
                               * This parameter is useless when using "fast" and "dFast" strategies.
                               * Special: value 0 means "do not change searchLog". */
     ZSTD_p_minMatch,         /* Minimum size of searched matches (note : repCode matches can be smaller).
                               * Larger values make faster compression and decompression, but decrease ratio.
                               * Must be clamped between ZSTD_SEARCHLENGTH_MIN and ZSTD_SEARCHLENGTH_MAX.
                               * Note that currently, for all strategies < btopt, effective minimum is 4.
                               * Note that currently, for all strategies > fast, effective maximum is 6.
                               * Special: value 0 means "do not change minMatchLength". */
     ZSTD_p_targetLength,     /* Only useful for strategies >= btopt.
                               * Length of Match considered "good enough" to stop search.
                               * Larger values make compression stronger and slower.
                               * Special: value 0 means "do not change targetLength". */
     ZSTD_p_compressionStrategy, /* See ZSTD_strategy enum definition.
                               * Cast selected strategy as unsigned for ZSTD_CCtx_setParameter() compatibility.
                               * The higher the value of selected strategy, the more complex it is,
                               * resulting in stronger and slower compression.
                               * Special: value 0 means "do not change strategy". */
 
     /* frame parameters */
-    ZSTD_p_contentSizeFlag=200, /* Content size is written into frame header _whenever known_ (default:1)
-                              * note that content size must be known at the beginning,
-                              * it is sent using ZSTD_CCtx_setPledgedSrcSize() */
+    ZSTD_p_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1)
+                              * Content size must be known at the beginning of compression,
+                              * it is provided using ZSTD_CCtx_setPledgedSrcSize() */
     ZSTD_p_checksumFlag,     /* A 32-bits checksum of content is written at end of frame (default:0) */
-    ZSTD_p_dictIDFlag,       /* When applicable, dictID of dictionary is provided in frame header (default:1) */
+    ZSTD_p_dictIDFlag,       /* When applicable, dictionary's ID is written into frame header (default:1) */
 
     /* multi-threading parameters */
     ZSTD_p_nbThreads=400,    /* Select how many threads a compression job can spawn (default:1)
                               * More threads improve speed, but also increase memory usage.
                               * Can only receive a value > 1 if ZSTD_MULTITHREAD is enabled.
                               * Special: value 0 means "do not change nbThreads" */
-    ZSTD_p_jobSize,          /* Size of a compression job. Each compression job is completed in parallel.
+    ZSTD_p_jobSize,          /* Size of a compression job. This value is only enforced in streaming (non-blocking) mode.
+                              * Each compression job is completed in parallel, so indirectly controls the nb of active threads.
                               * 0 means default, which is dynamically determined based on compression parameters.
                               * Job size must be a minimum of overlapSize, or 1 KB, whichever is largest
                               * The minimum size is automatically and transparently enforced */
     ZSTD_p_overlapSizeLog,   /* Size of previous input reloaded at the beginning of each job.
                               * 0 => no overlap, 6(default) => use 1/8th of windowSize, >=9 => use full windowSize */
 
     /* advanced parameters - may not remain available after API update */
     ZSTD_p_forceMaxWindow=1100, /* Force back-reference distances to remain < windowSize,
                               * even when referencing into Dictionary content (default:0) */
     ZSTD_p_enableLongDistanceMatching=1200,  /* Enable long distance matching.
                                          * This parameter is designed to improve the compression
                                          * ratio for large inputs with long distance matches.
                                          * This increases the memory usage as well as window size.
                                          * Note: setting this parameter sets all the LDM parameters
                                          * as well as ZSTD_p_windowLog. It should be set after
                                          * ZSTD_p_compressionLevel and before ZSTD_p_windowLog and
                                          * other LDM parameters. Setting the compression level
                                          * after this parameter overrides the window log, though LDM
                                          * will remain enabled until explicitly disabled. */
     ZSTD_p_ldmHashLog,   /* Size of the table for long distance matching, as a power of 2.
                           * Larger values increase memory usage and compression ratio, but decrease
                           * compression speed.
                           * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX
                           * (default: windowlog - 7). */
     ZSTD_p_ldmMinMatch,  /* Minimum size of searched matches for long distance matcher.
                           * Larger/too small values usually decrease compression ratio.
                           * Must be clamped between ZSTD_LDM_MINMATCH_MIN
                           * and ZSTD_LDM_MINMATCH_MAX (default: 64). */
     ZSTD_p_ldmBucketSizeLog,  /* Log size of each bucket in the LDM hash table for collision resolution.
                                * Larger values usually improve collision resolution but may decrease
                                * compression speed.
                                * The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX (default: 3). */
     ZSTD_p_ldmHashEveryLog,  /* Frequency of inserting/looking up entries in the LDM hash table.
                               * The default is MAX(0, (windowLog - ldmHashLog)) to
                               * optimize hash table usage.
                               * Larger values improve compression speed. Deviating far from the
                               * default value will likely result in a decrease in compression ratio.
                               * Must be clamped between 0 and ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN. */
 
 } ZSTD_cParameter;
 


 
size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, unsigned value);
 
  Set one compression parameter, selected by enum ZSTD_cParameter.
   Note : when `value` is an enum, cast it to unsigned for proper type checking.
-  @result : 0, or an error code (which can be tested with ZSTD_isError()). 
+  @result : informational value (typically, the one being set, possibly corrected),
+            or an error code (which can be tested with ZSTD_isError()). 
 


 
 
size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize);
 
  Total input data size to be compressed as a single frame.
   This value will be controlled at the end, and result in error if not respected.
  @result : 0, or an error code (which can be tested with ZSTD_isError()).
   Note 1 : 0 means zero, empty.
            In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN.
-           Note that ZSTD_CONTENTSIZE_UNKNOWN is default value for new compression jobs.
+           ZSTD_CONTENTSIZE_UNKNOWN is default value for any new compression job.
   Note 2 : If all data is provided and consumed in a single round,
            this value is overriden by srcSize instead. 
 


 
 
size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
 size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
 size_t ZSTD_CCtx_loadDictionary_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictMode_e dictMode);
 
  Create an internal CDict from dict buffer.
   Decompression will have to use same buffer.
  @result : 0, or an error code (which can be tested with ZSTD_isError()).
   Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary,
             meaning "return to no-dictionary mode".
   Note 1 : `dict` content will be copied internally. Use
             ZSTD_CCtx_loadDictionary_byReference() to reference dictionary
             content instead. The dictionary buffer must then outlive its
             users.
   Note 2 : Loading a dictionary involves building tables, which are dependent on compression parameters.
            For this reason, compression parameters cannot be changed anymore after loading a dictionary.
            It's also a CPU-heavy operation, with non-negligible impact on latency.
   Note 3 : Dictionary will be used for all future compression jobs.
            To return to "no-dictionary" situation, load a NULL dictionary
   Note 5 : Use ZSTD_CCtx_loadDictionary_advanced() to select how dictionary
            content will be interpreted.
  
 


 
 
size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict);
 
  Reference a prepared dictionary, to be used for all next compression jobs.
   Note that compression parameters are enforced from within CDict,
   and supercede any compression parameter previously set within CCtx.
   The dictionary will remain valid for future compression jobs using same CCtx.
  @result : 0, or an error code (which can be tested with ZSTD_isError()).
   Special : adding a NULL CDict means "return to no-dictionary mode".
   Note 1 : Currently, only one dictionary can be managed.
            Adding a new dictionary effectively "discards" any previous one.
   Note 2 : CDict is just referenced, its lifetime must outlive CCtx.
  
 


 
 
size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize);
 size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictMode_e dictMode);
 
  Reference a prefix (single-usage dictionary) for next compression job.
   Decompression need same prefix to properly regenerate data.
   Prefix is **only used once**. Tables are discarded at end of compression job.
   Subsequent compression jobs will be done without prefix (if none is explicitly referenced).
   If there is a need to use same prefix multiple times, consider embedding it into a ZSTD_CDict instead.
  @result : 0, or an error code (which can be tested with ZSTD_isError()).
   Special : Adding any prefix (including NULL) invalidates any previous prefix or dictionary
   Note 1 : Prefix buffer is referenced. It must outlive compression job.
   Note 2 : Referencing a prefix involves building tables, which are dependent on compression parameters.
            It's a CPU-heavy operation, with non-negligible impact on latency.
   Note 3 : By default, the prefix is treated as raw content
            (ZSTD_dm_rawContent). Use ZSTD_CCtx_refPrefix_advanced() to alter
            dictMode. 
 


 
 
typedef enum {
     ZSTD_e_continue=0, /* collect more data, encoder transparently decides when to output result, for optimal conditions */
     ZSTD_e_flush,      /* flush any data provided so far - frame will continue, future data can still reference previous data for better compression */
     ZSTD_e_end         /* flush any remaining data and close current frame. Any additional data starts a new frame. */
 } ZSTD_EndDirective;
 


 
size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
                               ZSTD_outBuffer* output,
                               ZSTD_inBuffer* input,
                               ZSTD_EndDirective endOp);
 
  Behave about the same as ZSTD_compressStream. To note :
   - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_setParameter()
   - Compression parameters cannot be changed once compression is started.
   - outpot->pos must be <= dstCapacity, input->pos must be <= srcSize
   - outpot->pos and input->pos will be updated. They are guaranteed to remain below their respective limit.
-  - @return provides the minimum amount of data still to flush from internal buffers
+  - In single-thread mode (default), function is blocking : it completed its job before returning to caller.
+  - In multi-thread mode, function is non-blocking : it just acquires a copy of input, and distribute job to internal worker threads,
+                                                     and then immediately returns, just indicating that there is some data remaining to be flushed.
+                                                     The function nonetheless guarantees forward progress : it will return only after it reads or write at least 1+ byte.
+  - Exception : in multi-threading mode, if the first call requests a ZSTD_e_end directive, it is blocking : it will complete compression before giving back control to caller.
+  - @return provides the minimum amount of data remaining to be flushed from internal buffers
             or an error code, which can be tested using ZSTD_isError().
-            if @return != 0, flush is not fully completed, there is some data left within internal buffers.
-  - after a ZSTD_e_end directive, if internal buffer is not fully flushed,
+            if @return != 0, flush is not fully completed, there is still some data left within internal buffers.
+            This is useful to determine if a ZSTD_e_flush or ZSTD_e_end directive is completed.
+  - after a ZSTD_e_end directive, if internal buffer is not fully flushed (@return != 0),
             only ZSTD_e_end or ZSTD_e_flush operations are allowed.
-            It is necessary to fully flush internal buffers
-            before starting a new compression job, or changing compression parameters.
+            Before starting a new compression job, or changing compression parameters,
+            it is required to fully flush internal buffers.
  
 


 
 
void ZSTD_CCtx_reset(ZSTD_CCtx* cctx);   /* Not ready yet ! */
 
  Return a CCtx to clean state.
   Useful after an error, or to interrupt an ongoing compression job and start a new one.
   Any internal data not yet flushed is cancelled.
   Dictionary (if any) is dropped.
   All parameters are back to default values.
   It's possible to modify compression parameters after a reset.
  
 


 
 
size_t ZSTD_compress_generic_simpleArgs (
                 ZSTD_CCtx* cctx,
                 void* dst, size_t dstCapacity, size_t* dstPos,
           const void* src, size_t srcSize, size_t* srcPos,
                 ZSTD_EndDirective endOp);
 
  Same as ZSTD_compress_generic(),
   but using only integral types as arguments.
   Argument list is larger than ZSTD_{in,out}Buffer,
   but can be helpful for binders from dynamic languages
   which have troubles handling structures containing memory pointers.
  
 


 
 
ZSTD_CCtx_params* ZSTD_createCCtxParams(void);
 
  Quick howto :
   - ZSTD_createCCtxParams() : Create a ZSTD_CCtx_params structure
   - ZSTD_CCtxParam_setParameter() : Push parameters one by one into
                                     an existing ZSTD_CCtx_params structure.
                                     This is similar to
                                     ZSTD_CCtx_setParameter().
   - ZSTD_CCtx_setParametersUsingCCtxParams() : Apply parameters to
                                     an existing CCtx.
                                     These parameters will be applied to
                                     all subsequent compression jobs.
   - ZSTD_compress_generic() : Do compression using the CCtx.
   - ZSTD_freeCCtxParams() : Free the memory.
 
   This can be used with ZSTD_estimateCCtxSize_advanced_usingCCtxParams()
   for static allocation for single-threaded compression.
  
 


 
 
size_t ZSTD_resetCCtxParams(ZSTD_CCtx_params* params);
 
  Reset params to default, with the default compression level.
  
 


 
 
size_t ZSTD_initCCtxParams(ZSTD_CCtx_params* cctxParams, int compressionLevel);
 
  Initializes the compression parameters of cctxParams according to
   compression level. All other parameters are reset to their default values.
  
 


 
 
size_t ZSTD_initCCtxParams_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params);
 
  Initializes the compression and frame parameters of cctxParams according to
   params. All other parameters are reset to their default values.
  
 


 
 
size_t ZSTD_CCtxParam_setParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, unsigned value);
 
  Similar to ZSTD_CCtx_setParameter.
   Set one compression parameter, selected by enum ZSTD_cParameter.
   Parameters must be applied to a ZSTD_CCtx using ZSTD_CCtx_setParametersUsingCCtxParams().
   Note : when `value` is an enum, cast it to unsigned for proper type checking.
  @result : 0, or an error code (which can be tested with ZSTD_isError()).
  
 


 
 
size_t ZSTD_CCtx_setParametersUsingCCtxParams(
         ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params);
 
  Apply a set of ZSTD_CCtx_params to the compression context.
   This must be done before the dictionary is loaded.
   The pledgedSrcSize is treated as unknown.
   Multithreading parameters are applied only if nbThreads > 1.
  
 


 
 
Advanced parameters for decompression API


 
size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);   /* not implemented */
 size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);   /* not implemented */
 size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictMode_e dictMode);   /* not implemented */
 
  Create an internal DDict from dict buffer,
   to be used to decompress next frames.
  @result : 0, or an error code (which can be tested with ZSTD_isError()).
   Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary,
             meaning "return to no-dictionary mode".
   Note 1 : `dict` content will be copied internally.
             Use ZSTD_DCtx_loadDictionary_byReference()
             to reference dictionary content instead.
             In which case, the dictionary buffer must outlive its users.
   Note 2 : Loading a dictionary involves building tables,
            which has a non-negligible impact on CPU usage and latency.
   Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to select
            how dictionary content will be interpreted and loaded.
  
 


 
 
size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict);   /* not implemented */
 
  Reference a prepared dictionary, to be used to decompress next frames.
   The dictionary remains active for decompression of future frames using same DCtx.
  @result : 0, or an error code (which can be tested with ZSTD_isError()).
   Note 1 : Currently, only one dictionary can be managed.
            Referencing a new dictionary effectively "discards" any previous one.
   Special : adding a NULL DDict means "return to no-dictionary mode".
   Note 2 : DDict is just referenced, its lifetime must outlive its usage from DCtx.
  
 


 
 
size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize);   /* not implemented */
 size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictMode_e dictMode);   /* not implemented */
 
  Reference a prefix (single-usage dictionary) for next compression job.
   Prefix is **only used once**. It must be explicitly referenced before each frame.
   If there is a need to use same prefix multiple times, consider embedding it into a ZSTD_DDict instead.
  @result : 0, or an error code (which can be tested with ZSTD_isError()).
   Note 1 : Adding any prefix (including NULL) invalidates any previously set prefix or dictionary
   Note 2 : Prefix buffer is referenced. It must outlive compression job.
   Note 3 : By default, the prefix is treated as raw content (ZSTD_dm_rawContent).
            Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode.
   Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost.
  
 


 
 
size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize);
 
  Refuses allocating internal buffers for frames requiring a window size larger than provided limit.
   This is useful to prevent a decoder context from reserving too much memory for itself (potential attack scenario).
   This parameter is only useful in streaming mode, since no internal buffer is allocated in direct mode.
   By default, a decompression context accepts all window sizes <= (1 << ZSTD_WINDOWLOG_MAX)
  @return : 0, or an error code (which can be tested using ZSTD_isError()).
  
 


 
 
size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format);
 
  Instruct the decoder context about what kind of data to decode next.
   This instruction is mandatory to decode data without a fully-formed header,
   such ZSTD_f_zstd1_magicless for example.
  @return : 0, or an error code (which can be tested using ZSTD_isError()).
  
 


 
 
size_t ZSTD_decompress_generic(ZSTD_DCtx* dctx,
                                ZSTD_outBuffer* output,
                                ZSTD_inBuffer* input);
 
  Behave the same as ZSTD_decompressStream.
   Decompression parameters cannot be changed once decompression is started.
  @return : an error code, which can be tested using ZSTD_isError()
            if >0, a hint, nb of expected input bytes for next invocation.
            `0` means : a frame has just been fully decoded and flushed.
  
 


 
 
size_t ZSTD_decompress_generic_simpleArgs (
                 ZSTD_DCtx* dctx,
                 void* dst, size_t dstCapacity, size_t* dstPos,
           const void* src, size_t srcSize, size_t* srcPos);
 
  Same as ZSTD_decompress_generic(),
   but using only integral types as arguments.
   Argument list is larger than ZSTD_{in,out}Buffer,
   but can be helpful for binders from dynamic languages
   which have troubles handling structures containing memory pointers.
  
 


 
 
void ZSTD_DCtx_reset(ZSTD_DCtx* dctx);
 
  Return a DCtx to clean state.
   If a decompression was ongoing, any internal data not yet flushed is cancelled.
   All parameters are back to default values, including sticky ones.
   Dictionary (if any) is dropped.
   Parameters can be modified again after a reset.
  
 


 
-
Block level API

+
Block level API

 
 
    Frame metadata cost is typically ~18 bytes, which can be non-negligible for very small blocks (< 100 bytes).
     User will have to take in charge required information to regenerate data, such as compressed and content sizes.
 
     A few rules to respect :
     - Compressing and decompressing require a context structure
       + Use ZSTD_createCCtx() and ZSTD_createDCtx()
     - It is necessary to init context before starting
       + compression : any ZSTD_compressBegin*() variant, including with dictionary
       + decompression : any ZSTD_decompressBegin*() variant, including with dictionary
       + copyCCtx() and copyDCtx() can be used too
     - Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX == 128 KB
       + If input is larger than a block size, it's necessary to split input data into multiple blocks
       + For inputs larger than a single block size, consider using the regular ZSTD_compress() instead.
         Frame metadata is not that costly, and quickly becomes negligible as source size grows larger.
     - When a block is considered not compressible enough, ZSTD_compressBlock() result will be zero.
       In which case, nothing is produced into `dst`.
       + User must test for such outcome and deal directly with uncompressed data
       + ZSTD_decompressBlock() doesn't accept uncompressed data as input !!!
       + In case of multiple successive blocks, should some of them be uncompressed,
         decoder must be informed of their existence in order to follow proper history.
         Use ZSTD_insertBlock() for such a case.
 


 
 
Raw zstd block functions
size_t ZSTD_getBlockSize   (const ZSTD_CCtx* cctx);
 size_t ZSTD_compressBlock  (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
 size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
 size_t ZSTD_insertBlock(ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize);  /**< insert uncompressed block into `dctx` history. Useful for multi-blocks decompression */
 


 
 
Index: head/sys/contrib/zstd/lib/BUCK
===================================================================
--- head/sys/contrib/zstd/lib/BUCK	(revision 330893)
+++ head/sys/contrib/zstd/lib/BUCK	(revision 330894)
@@ -1,186 +1,207 @@
 cxx_library(
     name='zstd',
     header_namespace='',
     visibility=['PUBLIC'],
     deps=[
         ':common',
         ':compress',
         ':decompress',
         ':deprecated',
     ],
 )
 
 cxx_library(
     name='compress',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
-        ('compress', 'zstdmt_compress.h'),
+        ('compress', 'zstd*.h'),
     ]),
-    headers=subdir_glob([
-        ('compress', 'zstd_opt.h'),
-    ]),
-    srcs=[
-        'compress/zstd_compress.c',
-        'compress/zstdmt_compress.c',
-    ],
+    srcs=glob(['compress/zstd*.c']),
     deps=[':common'],
 )
 
 cxx_library(
     name='decompress',
     header_namespace='',
     visibility=['PUBLIC'],
-    srcs=['decompress/zstd_decompress.c'],
+    srcs=glob(['decompress/zstd*.c']),
     deps=[
         ':common',
         ':legacy',
     ],
 )
 
 cxx_library(
     name='deprecated',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('decprecated', '*.h'),
     ]),
     srcs=glob(['deprecated/*.c']),
     deps=[':common'],
 )
 
 cxx_library(
     name='legacy',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('legacy', '*.h'),
     ]),
     srcs=glob(['legacy/*.c']),
     deps=[':common'],
+    exported_preprocessor_flags=[
+        '-DZSTD_LEGACY_SUPPORT=4',
+    ],
 )
 
 cxx_library(
     name='zdict',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('dictBuilder', 'zdict.h'),
     ]),
     headers=subdir_glob([
         ('dictBuilder', 'divsufsort.h'),
     ]),
     srcs=glob(['dictBuilder/*.c']),
     deps=[':common'],
 )
 
 cxx_library(
+    name='compiler',
+    header_namespace='',
+    visibility=['PUBLIC'],
+    exported_headers=subdir_glob([
+        ('common', 'compiler.h'),
+    ]),
+)
+
+cxx_library(
     name='bitstream',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('common', 'bitstream.h'),
     ]),
 )
 
 cxx_library(
     name='entropy',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('common', 'fse.h'),
         ('common', 'huf.h'),
     ]),
     srcs=[
         'common/entropy_common.c',
         'common/fse_decompress.c',
         'compress/fse_compress.c',
         'compress/huf_compress.c',
         'decompress/huf_decompress.c',
     ],
     deps=[
         ':bitstream',
+        ':compiler',
         ':errors',
         ':mem',
     ],
 )
 
 cxx_library(
     name='errors',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('common', 'error_private.h'),
         ('common', 'zstd_errors.h'),
     ]),
     srcs=['common/error_private.c'],
 )
 
 cxx_library(
     name='mem',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('common', 'mem.h'),
     ]),
 )
 
 cxx_library(
     name='pool',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('common', 'pool.h'),
     ]),
     srcs=['common/pool.c'],
-    deps=[':threading'],
+    deps=[
+        ':threading',
+        ':zstd_common',
+    ],
 )
 
 cxx_library(
     name='threading',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('common', 'threading.h'),
     ]),
     srcs=['common/threading.c'],
+    exported_preprocessor_flags=[
+        '-DZSTD_MULTITHREAD',
+    ],
+    exported_linker_flags=[
+        '-pthread',
+    ],
 )
 
 cxx_library(
     name='xxhash',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('common', 'xxhash.h'),
     ]),
     srcs=['common/xxhash.c'],
+    exported_preprocessor_flags=[
+        '-DXXH_NAMESPACE=ZSTD_',
+    ],
 )
 
 cxx_library(
     name='zstd_common',
     header_namespace='',
     visibility=['PUBLIC'],
     exported_headers=subdir_glob([
         ('', 'zstd.h'),
         ('common', 'zstd_internal.h'),
     ]),
     srcs=['common/zstd_common.c'],
     deps=[
+        ':compiler',
         ':errors',
         ':mem',
     ],
 )
 
 cxx_library(
     name='common',
     deps=[
         ':bitstream',
+        ':compiler',
         ':entropy',
         ':errors',
         ':mem',
         ':pool',
         ':threading',
         ':xxhash',
         ':zstd_common',
     ]
 )
Index: head/sys/contrib/zstd/lib/common/bitstream.h
===================================================================
--- head/sys/contrib/zstd/lib/common/bitstream.h	(revision 330893)
+++ head/sys/contrib/zstd/lib/common/bitstream.h	(revision 330894)
@@ -1,471 +1,471 @@
 /* ******************************************************************
    bitstream
    Part of FSE library
    header file (to include)
    Copyright (C) 2013-2017, Yann Collet.
 
    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:
 
        * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following disclaimer
    in the documentation and/or other materials provided with the
    distribution.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
    You can contact the author at :
    - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
 ****************************************************************** */
 #ifndef BITSTREAM_H_MODULE
 #define BITSTREAM_H_MODULE
 
 #if defined (__cplusplus)
 extern "C" {
 #endif
 
 /*
 *  This API consists of small unitary functions, which must be inlined for best performance.
 *  Since link-time-optimization is not available for all compilers,
 *  these functions are defined into a .h to be included.
 */
 
 /*-****************************************
 *  Dependencies
 ******************************************/
 #include "mem.h"            /* unaligned access routines */
 #include "error_private.h"  /* error codes and messages */
 
 
 /*-*************************************
 *  Debug
 ***************************************/
 #if defined(BIT_DEBUG) && (BIT_DEBUG>=1)
 #  include 
 #else
 #  ifndef assert
 #    define assert(condition) ((void)0)
 #  endif
 #endif
 
 
 /*=========================================
 *  Target specific
 =========================================*/
 #if defined(__BMI__) && defined(__GNUC__)
 #  include    /* support for bextr (experimental) */
 #endif
 
 #define STREAM_ACCUMULATOR_MIN_32  25
 #define STREAM_ACCUMULATOR_MIN_64  57
 #define STREAM_ACCUMULATOR_MIN    ((U32)(MEM_32bits() ? STREAM_ACCUMULATOR_MIN_32 : STREAM_ACCUMULATOR_MIN_64))
 
 
 /*-******************************************
 *  bitStream encoding API (write forward)
 ********************************************/
 /* bitStream can mix input from multiple sources.
  * A critical property of these streams is that they encode and decode in **reverse** direction.
  * So the first bit sequence you add will be the last to be read, like a LIFO stack.
  */
 typedef struct
 {
     size_t bitContainer;
     unsigned bitPos;
     char*  startPtr;
     char*  ptr;
     char*  endPtr;
 } BIT_CStream_t;
 
 MEM_STATIC size_t BIT_initCStream(BIT_CStream_t* bitC, void* dstBuffer, size_t dstCapacity);
 MEM_STATIC void   BIT_addBits(BIT_CStream_t* bitC, size_t value, unsigned nbBits);
 MEM_STATIC void   BIT_flushBits(BIT_CStream_t* bitC);
 MEM_STATIC size_t BIT_closeCStream(BIT_CStream_t* bitC);
 
 /* Start with initCStream, providing the size of buffer to write into.
 *  bitStream will never write outside of this buffer.
 *  `dstCapacity` must be >= sizeof(bitD->bitContainer), otherwise @return will be an error code.
 *
 *  bits are first added to a local register.
 *  Local register is size_t, hence 64-bits on 64-bits systems, or 32-bits on 32-bits systems.
 *  Writing data into memory is an explicit operation, performed by the flushBits function.
 *  Hence keep track how many bits are potentially stored into local register to avoid register overflow.
 *  After a flushBits, a maximum of 7 bits might still be stored into local register.
 *
 *  Avoid storing elements of more than 24 bits if you want compatibility with 32-bits bitstream readers.
 *
 *  Last operation is to close the bitStream.
 *  The function returns the final size of CStream in bytes.
 *  If data couldn't fit into `dstBuffer`, it will return a 0 ( == not storable)
 */
 
 
 /*-********************************************
 *  bitStream decoding API (read backward)
 **********************************************/
 typedef struct
 {
     size_t   bitContainer;
     unsigned bitsConsumed;
     const char* ptr;
     const char* start;
     const char* limitPtr;
 } BIT_DStream_t;
 
 typedef enum { BIT_DStream_unfinished = 0,
                BIT_DStream_endOfBuffer = 1,
                BIT_DStream_completed = 2,
                BIT_DStream_overflow = 3 } BIT_DStream_status;  /* result of BIT_reloadDStream() */
                /* 1,2,4,8 would be better for bitmap combinations, but slows down performance a bit ... :( */
 
 MEM_STATIC size_t   BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize);
 MEM_STATIC size_t   BIT_readBits(BIT_DStream_t* bitD, unsigned nbBits);
 MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD);
 MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* bitD);
 
 
 /* Start by invoking BIT_initDStream().
 *  A chunk of the bitStream is then stored into a local register.
 *  Local register size is 64-bits on 64-bits systems, 32-bits on 32-bits systems (size_t).
 *  You can then retrieve bitFields stored into the local register, **in reverse order**.
 *  Local register is explicitly reloaded from memory by the BIT_reloadDStream() method.
 *  A reload guarantee a minimum of ((8*sizeof(bitD->bitContainer))-7) bits when its result is BIT_DStream_unfinished.
 *  Otherwise, it can be less than that, so proceed accordingly.
 *  Checking if DStream has reached its end can be performed with BIT_endOfDStream().
 */
 
 
 /*-****************************************
 *  unsafe API
 ******************************************/
 MEM_STATIC void BIT_addBitsFast(BIT_CStream_t* bitC, size_t value, unsigned nbBits);
 /* faster, but works only if value is "clean", meaning all high bits above nbBits are 0 */
 
 MEM_STATIC void BIT_flushBitsFast(BIT_CStream_t* bitC);
 /* unsafe version; does not check buffer overflow */
 
 MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, unsigned nbBits);
 /* faster, but works only if nbBits >= 1 */
 
 
 
 /*-**************************************************************
 *  Internal functions
 ****************************************************************/
-MEM_STATIC unsigned BIT_highbit32 (register U32 val)
+MEM_STATIC unsigned BIT_highbit32 (U32 val)
 {
     assert(val != 0);
     {
 #   if defined(_MSC_VER)   /* Visual */
         unsigned long r=0;
         _BitScanReverse ( &r, val );
         return (unsigned) r;
 #   elif defined(__GNUC__) && (__GNUC__ >= 3) && __has_builtin(__builtin_clz)   /* Use GCC Intrinsic */
         return 31 - __builtin_clz (val);
 #   else   /* Software version */
         static const unsigned DeBruijnClz[32] = { 0,  9,  1, 10, 13, 21,  2, 29,
                                                  11, 14, 16, 18, 22, 25,  3, 30,
                                                   8, 12, 20, 28, 15, 17, 24,  7,
                                                  19, 27, 23,  6, 26,  5,  4, 31 };
         U32 v = val;
         v |= v >> 1;
         v |= v >> 2;
         v |= v >> 4;
         v |= v >> 8;
         v |= v >> 16;
         return DeBruijnClz[ (U32) (v * 0x07C4ACDDU) >> 27];
 #   endif
     }
 }
 
 /*=====    Local Constants   =====*/
 static const unsigned BIT_mask[] = {
     0,          1,         3,         7,         0xF,       0x1F,
     0x3F,       0x7F,      0xFF,      0x1FF,     0x3FF,     0x7FF,
     0xFFF,      0x1FFF,    0x3FFF,    0x7FFF,    0xFFFF,    0x1FFFF,
     0x3FFFF,    0x7FFFF,   0xFFFFF,   0x1FFFFF,  0x3FFFFF,  0x7FFFFF,
     0xFFFFFF,   0x1FFFFFF, 0x3FFFFFF, 0x7FFFFFF, 0xFFFFFFF, 0x1FFFFFFF,
     0x3FFFFFFF, 0x7FFFFFFF}; /* up to 31 bits */
 #define BIT_MASK_SIZE (sizeof(BIT_mask) / sizeof(BIT_mask[0]))
 
 /*-**************************************************************
 *  bitStream encoding
 ****************************************************************/
 /*! BIT_initCStream() :
  *  `dstCapacity` must be > sizeof(size_t)
  *  @return : 0 if success,
  *            otherwise an error code (can be tested using ERR_isError()) */
 MEM_STATIC size_t BIT_initCStream(BIT_CStream_t* bitC,
                                   void* startPtr, size_t dstCapacity)
 {
     bitC->bitContainer = 0;
     bitC->bitPos = 0;
     bitC->startPtr = (char*)startPtr;
     bitC->ptr = bitC->startPtr;
     bitC->endPtr = bitC->startPtr + dstCapacity - sizeof(bitC->bitContainer);
     if (dstCapacity <= sizeof(bitC->bitContainer)) return ERROR(dstSize_tooSmall);
     return 0;
 }
 
 /*! BIT_addBits() :
  *  can add up to 31 bits into `bitC`.
  *  Note : does not check for register overflow ! */
 MEM_STATIC void BIT_addBits(BIT_CStream_t* bitC,
                             size_t value, unsigned nbBits)
 {
     MEM_STATIC_ASSERT(BIT_MASK_SIZE == 32);
     assert(nbBits < BIT_MASK_SIZE);
     assert(nbBits + bitC->bitPos < sizeof(bitC->bitContainer) * 8);
     bitC->bitContainer |= (value & BIT_mask[nbBits]) << bitC->bitPos;
     bitC->bitPos += nbBits;
 }
 
 /*! BIT_addBitsFast() :
  *  works only if `value` is _clean_, meaning all high bits above nbBits are 0 */
 MEM_STATIC void BIT_addBitsFast(BIT_CStream_t* bitC,
                                 size_t value, unsigned nbBits)
 {
     assert((value>>nbBits) == 0);
     assert(nbBits + bitC->bitPos < sizeof(bitC->bitContainer) * 8);
     bitC->bitContainer |= value << bitC->bitPos;
     bitC->bitPos += nbBits;
 }
 
 /*! BIT_flushBitsFast() :
  *  assumption : bitContainer has not overflowed
  *  unsafe version; does not check buffer overflow */
 MEM_STATIC void BIT_flushBitsFast(BIT_CStream_t* bitC)
 {
     size_t const nbBytes = bitC->bitPos >> 3;
     assert(bitC->bitPos < sizeof(bitC->bitContainer) * 8);
     MEM_writeLEST(bitC->ptr, bitC->bitContainer);
     bitC->ptr += nbBytes;
     assert(bitC->ptr <= bitC->endPtr);
     bitC->bitPos &= 7;
     bitC->bitContainer >>= nbBytes*8;
 }
 
 /*! BIT_flushBits() :
  *  assumption : bitContainer has not overflowed
  *  safe version; check for buffer overflow, and prevents it.
  *  note : does not signal buffer overflow.
  *  overflow will be revealed later on using BIT_closeCStream() */
 MEM_STATIC void BIT_flushBits(BIT_CStream_t* bitC)
 {
     size_t const nbBytes = bitC->bitPos >> 3;
     assert(bitC->bitPos < sizeof(bitC->bitContainer) * 8);
     MEM_writeLEST(bitC->ptr, bitC->bitContainer);
     bitC->ptr += nbBytes;
     if (bitC->ptr > bitC->endPtr) bitC->ptr = bitC->endPtr;
     bitC->bitPos &= 7;
     bitC->bitContainer >>= nbBytes*8;
 }
 
 /*! BIT_closeCStream() :
  *  @return : size of CStream, in bytes,
  *            or 0 if it could not fit into dstBuffer */
 MEM_STATIC size_t BIT_closeCStream(BIT_CStream_t* bitC)
 {
     BIT_addBitsFast(bitC, 1, 1);   /* endMark */
     BIT_flushBits(bitC);
     if (bitC->ptr >= bitC->endPtr) return 0; /* overflow detected */
     return (bitC->ptr - bitC->startPtr) + (bitC->bitPos > 0);
 }
 
 
 /*-********************************************************
 *  bitStream decoding
 **********************************************************/
 /*! BIT_initDStream() :
  *  Initialize a BIT_DStream_t.
  * `bitD` : a pointer to an already allocated BIT_DStream_t structure.
  * `srcSize` must be the *exact* size of the bitStream, in bytes.
  * @return : size of stream (== srcSize), or an errorCode if a problem is detected
  */
 MEM_STATIC size_t BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize)
 {
     if (srcSize < 1) { memset(bitD, 0, sizeof(*bitD)); return ERROR(srcSize_wrong); }
 
     bitD->start = (const char*)srcBuffer;
     bitD->limitPtr = bitD->start + sizeof(bitD->bitContainer);
 
     if (srcSize >=  sizeof(bitD->bitContainer)) {  /* normal case */
         bitD->ptr   = (const char*)srcBuffer + srcSize - sizeof(bitD->bitContainer);
         bitD->bitContainer = MEM_readLEST(bitD->ptr);
         { BYTE const lastByte = ((const BYTE*)srcBuffer)[srcSize-1];
           bitD->bitsConsumed = lastByte ? 8 - BIT_highbit32(lastByte) : 0;  /* ensures bitsConsumed is always set */
           if (lastByte == 0) return ERROR(GENERIC); /* endMark not present */ }
     } else {
         bitD->ptr   = bitD->start;
         bitD->bitContainer = *(const BYTE*)(bitD->start);
         switch(srcSize)
         {
         case 7: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[6]) << (sizeof(bitD->bitContainer)*8 - 16);
                 /* fall-through */
 
         case 6: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[5]) << (sizeof(bitD->bitContainer)*8 - 24);
                 /* fall-through */
 
         case 5: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[4]) << (sizeof(bitD->bitContainer)*8 - 32);
                 /* fall-through */
 
         case 4: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[3]) << 24;
                 /* fall-through */
 
         case 3: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[2]) << 16;
                 /* fall-through */
 
         case 2: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[1]) <<  8;
                 /* fall-through */
 
         default: break;
         }
         {   BYTE const lastByte = ((const BYTE*)srcBuffer)[srcSize-1];
             bitD->bitsConsumed = lastByte ? 8 - BIT_highbit32(lastByte) : 0;
             if (lastByte == 0) return ERROR(corruption_detected);  /* endMark not present */
         }
         bitD->bitsConsumed += (U32)(sizeof(bitD->bitContainer) - srcSize)*8;
     }
 
     return srcSize;
 }
 
 MEM_STATIC size_t BIT_getUpperBits(size_t bitContainer, U32 const start)
 {
     return bitContainer >> start;
 }
 
 MEM_STATIC size_t BIT_getMiddleBits(size_t bitContainer, U32 const start, U32 const nbBits)
 {
 #if defined(__BMI__) && defined(__GNUC__) && __GNUC__*1000+__GNUC_MINOR__ >= 4008  /* experimental */
 #  if defined(__x86_64__)
     if (sizeof(bitContainer)==8)
         return _bextr_u64(bitContainer, start, nbBits);
     else
 #  endif
         return _bextr_u32(bitContainer, start, nbBits);
 #else
     assert(nbBits < BIT_MASK_SIZE);
     return (bitContainer >> start) & BIT_mask[nbBits];
 #endif
 }
 
 MEM_STATIC size_t BIT_getLowerBits(size_t bitContainer, U32 const nbBits)
 {
     assert(nbBits < BIT_MASK_SIZE);
     return bitContainer & BIT_mask[nbBits];
 }
 
 /*! BIT_lookBits() :
  *  Provides next n bits from local register.
  *  local register is not modified.
  *  On 32-bits, maxNbBits==24.
  *  On 64-bits, maxNbBits==56.
  * @return : value extracted */
 MEM_STATIC size_t BIT_lookBits(const BIT_DStream_t* bitD, U32 nbBits)
 {
 #if defined(__BMI__) && defined(__GNUC__)   /* experimental; fails if bitD->bitsConsumed + nbBits > sizeof(bitD->bitContainer)*8 */
     return BIT_getMiddleBits(bitD->bitContainer, (sizeof(bitD->bitContainer)*8) - bitD->bitsConsumed - nbBits, nbBits);
 #else
     U32 const regMask = sizeof(bitD->bitContainer)*8 - 1;
     return ((bitD->bitContainer << (bitD->bitsConsumed & regMask)) >> 1) >> ((regMask-nbBits) & regMask);
 #endif
 }
 
 /*! BIT_lookBitsFast() :
  *  unsafe version; only works if nbBits >= 1 */
 MEM_STATIC size_t BIT_lookBitsFast(const BIT_DStream_t* bitD, U32 nbBits)
 {
     U32 const regMask = sizeof(bitD->bitContainer)*8 - 1;
     assert(nbBits >= 1);
     return (bitD->bitContainer << (bitD->bitsConsumed & regMask)) >> (((regMask+1)-nbBits) & regMask);
 }
 
 MEM_STATIC void BIT_skipBits(BIT_DStream_t* bitD, U32 nbBits)
 {
     bitD->bitsConsumed += nbBits;
 }
 
 /*! BIT_readBits() :
  *  Read (consume) next n bits from local register and update.
  *  Pay attention to not read more than nbBits contained into local register.
  * @return : extracted value. */
 MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, U32 nbBits)
 {
     size_t const value = BIT_lookBits(bitD, nbBits);
     BIT_skipBits(bitD, nbBits);
     return value;
 }
 
 /*! BIT_readBitsFast() :
  *  unsafe version; only works only if nbBits >= 1 */
 MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, U32 nbBits)
 {
     size_t const value = BIT_lookBitsFast(bitD, nbBits);
     assert(nbBits >= 1);
     BIT_skipBits(bitD, nbBits);
     return value;
 }
 
 /*! BIT_reloadDStream() :
  *  Refill `bitD` from buffer previously set in BIT_initDStream() .
  *  This function is safe, it guarantees it will not read beyond src buffer.
  * @return : status of `BIT_DStream_t` internal register.
  *           when status == BIT_DStream_unfinished, internal register is filled with at least 25 or 57 bits */
 MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD)
 {
     if (bitD->bitsConsumed > (sizeof(bitD->bitContainer)*8))  /* overflow detected, like end of stream */
         return BIT_DStream_overflow;
 
     if (bitD->ptr >= bitD->limitPtr) {
         bitD->ptr -= bitD->bitsConsumed >> 3;
         bitD->bitsConsumed &= 7;
         bitD->bitContainer = MEM_readLEST(bitD->ptr);
         return BIT_DStream_unfinished;
     }
     if (bitD->ptr == bitD->start) {
         if (bitD->bitsConsumed < sizeof(bitD->bitContainer)*8) return BIT_DStream_endOfBuffer;
         return BIT_DStream_completed;
     }
     /* start < ptr < limitPtr */
     {   U32 nbBytes = bitD->bitsConsumed >> 3;
         BIT_DStream_status result = BIT_DStream_unfinished;
         if (bitD->ptr - nbBytes < bitD->start) {
             nbBytes = (U32)(bitD->ptr - bitD->start);  /* ptr > start */
             result = BIT_DStream_endOfBuffer;
         }
         bitD->ptr -= nbBytes;
         bitD->bitsConsumed -= nbBytes*8;
         bitD->bitContainer = MEM_readLEST(bitD->ptr);   /* reminder : srcSize > sizeof(bitD->bitContainer), otherwise bitD->ptr == bitD->start */
         return result;
     }
 }
 
 /*! BIT_endOfDStream() :
  * @return : 1 if DStream has _exactly_ reached its end (all bits consumed).
  */
 MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* DStream)
 {
     return ((DStream->ptr == DStream->start) && (DStream->bitsConsumed == sizeof(DStream->bitContainer)*8));
 }
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif /* BITSTREAM_H_MODULE */
Index: head/sys/contrib/zstd/lib/common/mem.h
===================================================================
--- head/sys/contrib/zstd/lib/common/mem.h	(revision 330893)
+++ head/sys/contrib/zstd/lib/common/mem.h	(revision 330894)
@@ -1,360 +1,362 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 #ifndef MEM_H_MODULE
 #define MEM_H_MODULE
 
 #if defined (__cplusplus)
 extern "C" {
 #endif
 
 /*-****************************************
 *  Dependencies
 ******************************************/
 #include      /* size_t, ptrdiff_t */
 #include      /* memcpy */
 
 
 /*-****************************************
 *  Compiler specifics
 ******************************************/
 #if defined(_MSC_VER)   /* Visual Studio */
 #   include   /* _byteswap_ulong */
 #   include   /* _byteswap_* */
 #endif
 #if defined(__GNUC__)
 #  define MEM_STATIC static __inline __attribute__((unused))
 #elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
 #  define MEM_STATIC static inline
 #elif defined(_MSC_VER)
 #  define MEM_STATIC static __inline
 #else
 #  define MEM_STATIC static  /* this version may generate warnings for unused static functions; disable the relevant warning */
 #endif
 
 /* code only tested on 32 and 64 bits systems */
 #define MEM_STATIC_ASSERT(c)   { enum { MEM_static_assert = 1/(int)(!!(c)) }; }
 MEM_STATIC void MEM_check(void) { MEM_STATIC_ASSERT((sizeof(size_t)==4) || (sizeof(size_t)==8)); }
 
 
 /*-**************************************************************
 *  Basic Types
 *****************************************************************/
 #if  !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
 # include 
   typedef   uint8_t BYTE;
   typedef  uint16_t U16;
   typedef   int16_t S16;
   typedef  uint32_t U32;
   typedef   int32_t S32;
   typedef  uint64_t U64;
   typedef   int64_t S64;
-  typedef  intptr_t iPtrDiff;
-  typedef uintptr_t uPtrDiff;
 #else
   typedef unsigned char      BYTE;
   typedef unsigned short      U16;
   typedef   signed short      S16;
   typedef unsigned int        U32;
   typedef   signed int        S32;
   typedef unsigned long long  U64;
   typedef   signed long long  S64;
-  typedef ptrdiff_t      iPtrDiff;
-  typedef size_t         uPtrDiff;
 #endif
 
 
 /*-**************************************************************
 *  Memory I/O
 *****************************************************************/
 /* MEM_FORCE_MEMORY_ACCESS :
  * By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable.
  * Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal.
  * The below switch allow to select different access method for improved performance.
  * Method 0 (default) : use `memcpy()`. Safe and portable.
  * Method 1 : `__packed` statement. It depends on compiler extension (i.e., not portable).
  *            This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`.
  * Method 2 : direct access. This method is portable but violate C standard.
  *            It can generate buggy code on targets depending on alignment.
  *            In some circumstances, it's the only known way to get the most performance (i.e. GCC + ARMv6)
  * See http://fastcompression.blogspot.fr/2015/08/accessing-unaligned-memory.html for details.
  * Prefer these methods in priority order (0 > 1 > 2)
  */
 #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
 #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
 #    define MEM_FORCE_MEMORY_ACCESS 2
 #  elif defined(__INTEL_COMPILER) || defined(__GNUC__)
 #    define MEM_FORCE_MEMORY_ACCESS 1
 #  endif
 #endif
 
 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(size_t)==4; }
 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(size_t)==8; }
 
 MEM_STATIC unsigned MEM_isLittleEndian(void)
 {
     const union { U32 u; BYTE c[4]; } one = { 1 };   /* don't use static : performance detrimental  */
     return one.c[0];
 }
 
 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2)
 
 /* violates C standard, by lying on structure alignment.
 Only use if no other choice to achieve best performance on target platform */
 MEM_STATIC U16 MEM_read16(const void* memPtr) { return *(const U16*) memPtr; }
 MEM_STATIC U32 MEM_read32(const void* memPtr) { return *(const U32*) memPtr; }
 MEM_STATIC U64 MEM_read64(const void* memPtr) { return *(const U64*) memPtr; }
 MEM_STATIC size_t MEM_readST(const void* memPtr) { return *(const size_t*) memPtr; }
 
 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; }
 MEM_STATIC void MEM_write32(void* memPtr, U32 value) { *(U32*)memPtr = value; }
 MEM_STATIC void MEM_write64(void* memPtr, U64 value) { *(U64*)memPtr = value; }
 
 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1)
 
 /* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
 /* currently only defined for gcc and icc */
 #if defined(_MSC_VER) || (defined(__INTEL_COMPILER) && defined(WIN32))
     __pragma( pack(push, 1) )
-    typedef union { U16 u16; U32 u32; U64 u64; size_t st; } unalign;
+    typedef struct { U16 v; } unalign16;
+    typedef struct { U32 v; } unalign32;
+    typedef struct { U64 v; } unalign64;
+    typedef struct { size_t v; } unalignArch;
     __pragma( pack(pop) )
 #else
-    typedef union { U16 u16; U32 u32; U64 u64; size_t st; } __attribute__((packed)) unalign;
+    typedef struct { U16 v; } __attribute__((packed)) unalign16;
+    typedef struct { U32 v; } __attribute__((packed)) unalign32;
+    typedef struct { U64 v; } __attribute__((packed)) unalign64;
+    typedef struct { size_t v; } __attribute__((packed)) unalignArch;
 #endif
 
-MEM_STATIC U16 MEM_read16(const void* ptr) { return ((const unalign*)ptr)->u16; }
-MEM_STATIC U32 MEM_read32(const void* ptr) { return ((const unalign*)ptr)->u32; }
-MEM_STATIC U64 MEM_read64(const void* ptr) { return ((const unalign*)ptr)->u64; }
-MEM_STATIC size_t MEM_readST(const void* ptr) { return ((const unalign*)ptr)->st; }
+MEM_STATIC U16 MEM_read16(const void* ptr) { return ((const unalign16*)ptr)->v; }
+MEM_STATIC U32 MEM_read32(const void* ptr) { return ((const unalign32*)ptr)->v; }
+MEM_STATIC U64 MEM_read64(const void* ptr) { return ((const unalign64*)ptr)->v; }
+MEM_STATIC size_t MEM_readST(const void* ptr) { return ((const unalignArch*)ptr)->v; }
 
-MEM_STATIC void MEM_write16(void* memPtr, U16 value) { ((unalign*)memPtr)->u16 = value; }
-MEM_STATIC void MEM_write32(void* memPtr, U32 value) { ((unalign*)memPtr)->u32 = value; }
-MEM_STATIC void MEM_write64(void* memPtr, U64 value) { ((unalign*)memPtr)->u64 = value; }
+MEM_STATIC void MEM_write16(void* memPtr, U16 value) { ((unalign16*)memPtr)->v = value; }
+MEM_STATIC void MEM_write32(void* memPtr, U32 value) { ((unalign32*)memPtr)->v = value; }
+MEM_STATIC void MEM_write64(void* memPtr, U64 value) { ((unalign64*)memPtr)->v = value; }
 
 #else
 
 /* default method, safe and standard.
    can sometimes prove slower */
 
 MEM_STATIC U16 MEM_read16(const void* memPtr)
 {
     U16 val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
 MEM_STATIC U32 MEM_read32(const void* memPtr)
 {
     U32 val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
 MEM_STATIC U64 MEM_read64(const void* memPtr)
 {
     U64 val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
 MEM_STATIC size_t MEM_readST(const void* memPtr)
 {
     size_t val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
 MEM_STATIC void MEM_write16(void* memPtr, U16 value)
 {
     memcpy(memPtr, &value, sizeof(value));
 }
 
 MEM_STATIC void MEM_write32(void* memPtr, U32 value)
 {
     memcpy(memPtr, &value, sizeof(value));
 }
 
 MEM_STATIC void MEM_write64(void* memPtr, U64 value)
 {
     memcpy(memPtr, &value, sizeof(value));
 }
 
 #endif /* MEM_FORCE_MEMORY_ACCESS */
 
 MEM_STATIC U32 MEM_swap32(U32 in)
 {
 #if defined(_MSC_VER)     /* Visual Studio */
     return _byteswap_ulong(in);
 #elif defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)
     return __builtin_bswap32(in);
 #else
     return  ((in << 24) & 0xff000000 ) |
             ((in <<  8) & 0x00ff0000 ) |
             ((in >>  8) & 0x0000ff00 ) |
             ((in >> 24) & 0x000000ff );
 #endif
 }
 
 MEM_STATIC U64 MEM_swap64(U64 in)
 {
 #if defined(_MSC_VER)     /* Visual Studio */
     return _byteswap_uint64(in);
 #elif defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 403)
     return __builtin_bswap64(in);
 #else
     return  ((in << 56) & 0xff00000000000000ULL) |
             ((in << 40) & 0x00ff000000000000ULL) |
             ((in << 24) & 0x0000ff0000000000ULL) |
             ((in << 8)  & 0x000000ff00000000ULL) |
             ((in >> 8)  & 0x00000000ff000000ULL) |
             ((in >> 24) & 0x0000000000ff0000ULL) |
             ((in >> 40) & 0x000000000000ff00ULL) |
             ((in >> 56) & 0x00000000000000ffULL);
 #endif
 }
 
 MEM_STATIC size_t MEM_swapST(size_t in)
 {
     if (MEM_32bits())
         return (size_t)MEM_swap32((U32)in);
     else
         return (size_t)MEM_swap64((U64)in);
 }
 
 /*=== Little endian r/w ===*/
 
 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
 {
     if (MEM_isLittleEndian())
         return MEM_read16(memPtr);
     else {
         const BYTE* p = (const BYTE*)memPtr;
         return (U16)(p[0] + (p[1]<<8));
     }
 }
 
 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val)
 {
     if (MEM_isLittleEndian()) {
         MEM_write16(memPtr, val);
     } else {
         BYTE* p = (BYTE*)memPtr;
         p[0] = (BYTE)val;
         p[1] = (BYTE)(val>>8);
     }
 }
 
 MEM_STATIC U32 MEM_readLE24(const void* memPtr)
 {
     return MEM_readLE16(memPtr) + (((const BYTE*)memPtr)[2] << 16);
 }
 
 MEM_STATIC void MEM_writeLE24(void* memPtr, U32 val)
 {
     MEM_writeLE16(memPtr, (U16)val);
     ((BYTE*)memPtr)[2] = (BYTE)(val>>16);
 }
 
 MEM_STATIC U32 MEM_readLE32(const void* memPtr)
 {
     if (MEM_isLittleEndian())
         return MEM_read32(memPtr);
     else
         return MEM_swap32(MEM_read32(memPtr));
 }
 
 MEM_STATIC void MEM_writeLE32(void* memPtr, U32 val32)
 {
     if (MEM_isLittleEndian())
         MEM_write32(memPtr, val32);
     else
         MEM_write32(memPtr, MEM_swap32(val32));
 }
 
 MEM_STATIC U64 MEM_readLE64(const void* memPtr)
 {
     if (MEM_isLittleEndian())
         return MEM_read64(memPtr);
     else
         return MEM_swap64(MEM_read64(memPtr));
 }
 
 MEM_STATIC void MEM_writeLE64(void* memPtr, U64 val64)
 {
     if (MEM_isLittleEndian())
         MEM_write64(memPtr, val64);
     else
         MEM_write64(memPtr, MEM_swap64(val64));
 }
 
 MEM_STATIC size_t MEM_readLEST(const void* memPtr)
 {
     if (MEM_32bits())
         return (size_t)MEM_readLE32(memPtr);
     else
         return (size_t)MEM_readLE64(memPtr);
 }
 
 MEM_STATIC void MEM_writeLEST(void* memPtr, size_t val)
 {
     if (MEM_32bits())
         MEM_writeLE32(memPtr, (U32)val);
     else
         MEM_writeLE64(memPtr, (U64)val);
 }
 
 /*=== Big endian r/w ===*/
 
 MEM_STATIC U32 MEM_readBE32(const void* memPtr)
 {
     if (MEM_isLittleEndian())
         return MEM_swap32(MEM_read32(memPtr));
     else
         return MEM_read32(memPtr);
 }
 
 MEM_STATIC void MEM_writeBE32(void* memPtr, U32 val32)
 {
     if (MEM_isLittleEndian())
         MEM_write32(memPtr, MEM_swap32(val32));
     else
         MEM_write32(memPtr, val32);
 }
 
 MEM_STATIC U64 MEM_readBE64(const void* memPtr)
 {
     if (MEM_isLittleEndian())
         return MEM_swap64(MEM_read64(memPtr));
     else
         return MEM_read64(memPtr);
 }
 
 MEM_STATIC void MEM_writeBE64(void* memPtr, U64 val64)
 {
     if (MEM_isLittleEndian())
         MEM_write64(memPtr, MEM_swap64(val64));
     else
         MEM_write64(memPtr, val64);
 }
 
 MEM_STATIC size_t MEM_readBEST(const void* memPtr)
 {
     if (MEM_32bits())
         return (size_t)MEM_readBE32(memPtr);
     else
         return (size_t)MEM_readBE64(memPtr);
 }
 
 MEM_STATIC void MEM_writeBEST(void* memPtr, size_t val)
 {
     if (MEM_32bits())
         MEM_writeBE32(memPtr, (U32)val);
     else
         MEM_writeBE64(memPtr, (U64)val);
 }
 
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif /* MEM_H_MODULE */
Index: head/sys/contrib/zstd/lib/common/pool.c
===================================================================
--- head/sys/contrib/zstd/lib/common/pool.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/common/pool.c	(revision 330894)
@@ -1,255 +1,254 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 
 /* ======   Dependencies   ======= */
 #include   /* size_t */
-#include   /* malloc, calloc, free */
 #include "pool.h"
 
 /* ======   Compiler specifics   ====== */
 #if defined(_MSC_VER)
 #  pragma warning(disable : 4204)        /* disable: C4204: non-constant aggregate initializer */
 #endif
 
 
 #ifdef ZSTD_MULTITHREAD
 
 #include "threading.h"   /* pthread adaptation */
 
 /* A job is a function and an opaque argument */
 typedef struct POOL_job_s {
     POOL_function function;
     void *opaque;
 } POOL_job;
 
 struct POOL_ctx_s {
     ZSTD_customMem customMem;
     /* Keep track of the threads */
     ZSTD_pthread_t *threads;
     size_t numThreads;
 
     /* The queue is a circular buffer */
     POOL_job *queue;
     size_t queueHead;
     size_t queueTail;
     size_t queueSize;
 
     /* The number of threads working on jobs */
     size_t numThreadsBusy;
     /* Indicates if the queue is empty */
     int queueEmpty;
 
     /* The mutex protects the queue */
     ZSTD_pthread_mutex_t queueMutex;
     /* Condition variable for pushers to wait on when the queue is full */
     ZSTD_pthread_cond_t queuePushCond;
     /* Condition variables for poppers to wait on when the queue is empty */
     ZSTD_pthread_cond_t queuePopCond;
     /* Indicates if the queue is shutting down */
     int shutdown;
 };
 
 /* POOL_thread() :
    Work thread for the thread pool.
    Waits for jobs and executes them.
    @returns : NULL on failure else non-null.
 */
 static void* POOL_thread(void* opaque) {
     POOL_ctx* const ctx = (POOL_ctx*)opaque;
     if (!ctx) { return NULL; }
     for (;;) {
         /* Lock the mutex and wait for a non-empty queue or until shutdown */
         ZSTD_pthread_mutex_lock(&ctx->queueMutex);
 
         while (ctx->queueEmpty && !ctx->shutdown) {
             ZSTD_pthread_cond_wait(&ctx->queuePopCond, &ctx->queueMutex);
         }
         /* empty => shutting down: so stop */
         if (ctx->queueEmpty) {
             ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
             return opaque;
         }
         /* Pop a job off the queue */
         {   POOL_job const job = ctx->queue[ctx->queueHead];
             ctx->queueHead = (ctx->queueHead + 1) % ctx->queueSize;
             ctx->numThreadsBusy++;
             ctx->queueEmpty = ctx->queueHead == ctx->queueTail;
             /* Unlock the mutex, signal a pusher, and run the job */
             ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
             ZSTD_pthread_cond_signal(&ctx->queuePushCond);
 
             job.function(job.opaque);
 
             /* If the intended queue size was 0, signal after finishing job */
             if (ctx->queueSize == 1) {
                 ZSTD_pthread_mutex_lock(&ctx->queueMutex);
                 ctx->numThreadsBusy--;
                 ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
                 ZSTD_pthread_cond_signal(&ctx->queuePushCond);
         }   }
     }  /* for (;;) */
     /* Unreachable */
 }
 
 POOL_ctx* POOL_create(size_t numThreads, size_t queueSize) {
     return POOL_create_advanced(numThreads, queueSize, ZSTD_defaultCMem);
 }
 
 POOL_ctx* POOL_create_advanced(size_t numThreads, size_t queueSize, ZSTD_customMem customMem) {
     POOL_ctx* ctx;
     /* Check the parameters */
     if (!numThreads) { return NULL; }
     /* Allocate the context and zero initialize */
     ctx = (POOL_ctx*)ZSTD_calloc(sizeof(POOL_ctx), customMem);
     if (!ctx) { return NULL; }
     /* Initialize the job queue.
      * It needs one extra space since one space is wasted to differentiate empty
      * and full queues.
      */
     ctx->queueSize = queueSize + 1;
-    ctx->queue = (POOL_job*) malloc(ctx->queueSize * sizeof(POOL_job));
+    ctx->queue = (POOL_job*)ZSTD_malloc(ctx->queueSize * sizeof(POOL_job), customMem);
     ctx->queueHead = 0;
     ctx->queueTail = 0;
     ctx->numThreadsBusy = 0;
     ctx->queueEmpty = 1;
     (void)ZSTD_pthread_mutex_init(&ctx->queueMutex, NULL);
     (void)ZSTD_pthread_cond_init(&ctx->queuePushCond, NULL);
     (void)ZSTD_pthread_cond_init(&ctx->queuePopCond, NULL);
     ctx->shutdown = 0;
     /* Allocate space for the thread handles */
     ctx->threads = (ZSTD_pthread_t*)ZSTD_malloc(numThreads * sizeof(ZSTD_pthread_t), customMem);
     ctx->numThreads = 0;
     ctx->customMem = customMem;
     /* Check for errors */
     if (!ctx->threads || !ctx->queue) { POOL_free(ctx); return NULL; }
     /* Initialize the threads */
     {   size_t i;
         for (i = 0; i < numThreads; ++i) {
             if (ZSTD_pthread_create(&ctx->threads[i], NULL, &POOL_thread, ctx)) {
                 ctx->numThreads = i;
                 POOL_free(ctx);
                 return NULL;
         }   }
         ctx->numThreads = numThreads;
     }
     return ctx;
 }
 
 /*! POOL_join() :
     Shutdown the queue, wake any sleeping threads, and join all of the threads.
 */
 static void POOL_join(POOL_ctx* ctx) {
     /* Shut down the queue */
     ZSTD_pthread_mutex_lock(&ctx->queueMutex);
     ctx->shutdown = 1;
     ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
     /* Wake up sleeping threads */
     ZSTD_pthread_cond_broadcast(&ctx->queuePushCond);
     ZSTD_pthread_cond_broadcast(&ctx->queuePopCond);
     /* Join all of the threads */
     {   size_t i;
         for (i = 0; i < ctx->numThreads; ++i) {
             ZSTD_pthread_join(ctx->threads[i], NULL);
     }   }
 }
 
 void POOL_free(POOL_ctx *ctx) {
     if (!ctx) { return; }
     POOL_join(ctx);
     ZSTD_pthread_mutex_destroy(&ctx->queueMutex);
     ZSTD_pthread_cond_destroy(&ctx->queuePushCond);
     ZSTD_pthread_cond_destroy(&ctx->queuePopCond);
     ZSTD_free(ctx->queue, ctx->customMem);
     ZSTD_free(ctx->threads, ctx->customMem);
     ZSTD_free(ctx, ctx->customMem);
 }
 
 size_t POOL_sizeof(POOL_ctx *ctx) {
     if (ctx==NULL) return 0;  /* supports sizeof NULL */
     return sizeof(*ctx)
         + ctx->queueSize * sizeof(POOL_job)
         + ctx->numThreads * sizeof(ZSTD_pthread_t);
 }
 
 /**
  * Returns 1 if the queue is full and 0 otherwise.
  *
  * If the queueSize is 1 (the pool was created with an intended queueSize of 0),
  * then a queue is empty if there is a thread free and no job is waiting.
  */
 static int isQueueFull(POOL_ctx const* ctx) {
     if (ctx->queueSize > 1) {
         return ctx->queueHead == ((ctx->queueTail + 1) % ctx->queueSize);
     } else {
         return ctx->numThreadsBusy == ctx->numThreads ||
                !ctx->queueEmpty;
     }
 }
 
 void POOL_add(void* ctxVoid, POOL_function function, void *opaque) {
     POOL_ctx* const ctx = (POOL_ctx*)ctxVoid;
     if (!ctx) { return; }
 
     ZSTD_pthread_mutex_lock(&ctx->queueMutex);
     {   POOL_job const job = {function, opaque};
 
         /* Wait until there is space in the queue for the new job */
         while (isQueueFull(ctx) && !ctx->shutdown) {
           ZSTD_pthread_cond_wait(&ctx->queuePushCond, &ctx->queueMutex);
         }
         /* The queue is still going => there is space */
         if (!ctx->shutdown) {
             ctx->queueEmpty = 0;
             ctx->queue[ctx->queueTail] = job;
             ctx->queueTail = (ctx->queueTail + 1) % ctx->queueSize;
         }
     }
     ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
     ZSTD_pthread_cond_signal(&ctx->queuePopCond);
 }
 
 #else  /* ZSTD_MULTITHREAD  not defined */
 /* No multi-threading support */
 
 /* We don't need any data, but if it is empty malloc() might return NULL. */
 struct POOL_ctx_s {
     int dummy;
 };
 static POOL_ctx g_ctx;
 
 POOL_ctx* POOL_create(size_t numThreads, size_t queueSize) {
     return POOL_create_advanced(numThreads, queueSize, ZSTD_defaultCMem);
 }
 
 POOL_ctx* POOL_create_advanced(size_t numThreads, size_t queueSize, ZSTD_customMem customMem) {
     (void)numThreads;
     (void)queueSize;
     (void)customMem;
     return &g_ctx;
 }
 
 void POOL_free(POOL_ctx* ctx) {
     assert(!ctx || ctx == &g_ctx);
     (void)ctx;
 }
 
 void POOL_add(void* ctx, POOL_function function, void* opaque) {
     (void)ctx;
     function(opaque);
 }
 
 size_t POOL_sizeof(POOL_ctx* ctx) {
     if (ctx==NULL) return 0;  /* supports sizeof NULL */
     assert(ctx == &g_ctx);
     return sizeof(*ctx);
 }
 
 #endif  /* ZSTD_MULTITHREAD */
Index: head/sys/contrib/zstd/lib/common/xxhash.c
===================================================================
--- head/sys/contrib/zstd/lib/common/xxhash.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/common/xxhash.c	(revision 330894)
@@ -1,875 +1,875 @@
 /*
 *  xxHash - Fast Hash algorithm
 *  Copyright (C) 2012-2016, Yann Collet
 *
 *  BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are
 *  met:
 *
 *  * Redistributions of source code must retain the above copyright
 *  notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above
 *  copyright notice, this list of conditions and the following disclaimer
 *  in the documentation and/or other materials provided with the
 *  distribution.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  You can contact the author at :
 *  - xxHash homepage: http://www.xxhash.com
 *  - xxHash source repository : https://github.com/Cyan4973/xxHash
 */
 
 
 /* *************************************
 *  Tuning parameters
 ***************************************/
 /*!XXH_FORCE_MEMORY_ACCESS :
  * By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable.
  * Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal.
  * The below switch allow to select different access method for improved performance.
  * Method 0 (default) : use `memcpy()`. Safe and portable.
  * Method 1 : `__packed` statement. It depends on compiler extension (ie, not portable).
  *            This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`.
  * Method 2 : direct access. This method doesn't depend on compiler but violate C standard.
  *            It can generate buggy code on targets which do not support unaligned memory accesses.
  *            But in some circumstances, it's the only known way to get the most performance (ie GCC + ARMv6)
  * See http://stackoverflow.com/a/32095106/646947 for details.
  * Prefer these methods in priority order (0 > 1 > 2)
  */
 #ifndef XXH_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
 #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
 #    define XXH_FORCE_MEMORY_ACCESS 2
 #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) ))
 #    define XXH_FORCE_MEMORY_ACCESS 1
 #  endif
 #endif
 
 /*!XXH_ACCEPT_NULL_INPUT_POINTER :
  * If the input pointer is a null pointer, xxHash default behavior is to trigger a memory access error, since it is a bad pointer.
  * When this option is enabled, xxHash output for null input pointers will be the same as a null-length input.
  * By default, this option is disabled. To enable it, uncomment below define :
  */
 /* #define XXH_ACCEPT_NULL_INPUT_POINTER 1 */
 
 /*!XXH_FORCE_NATIVE_FORMAT :
  * By default, xxHash library provides endian-independant Hash values, based on little-endian convention.
  * Results are therefore identical for little-endian and big-endian CPU.
  * This comes at a performance cost for big-endian CPU, since some swapping is required to emulate little-endian format.
  * Should endian-independance be of no importance for your application, you may set the #define below to 1,
  * to improve speed for Big-endian CPU.
  * This option has no impact on Little_Endian CPU.
  */
 #ifndef XXH_FORCE_NATIVE_FORMAT   /* can be defined externally */
 #  define XXH_FORCE_NATIVE_FORMAT 0
 #endif
 
 /*!XXH_FORCE_ALIGN_CHECK :
  * This is a minor performance trick, only useful with lots of very small keys.
  * It means : check for aligned/unaligned input.
  * The check costs one initial branch per hash; set to 0 when the input data
  * is guaranteed to be aligned.
  */
 #ifndef XXH_FORCE_ALIGN_CHECK /* can be defined externally */
 #  if defined(__i386) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_X64)
 #    define XXH_FORCE_ALIGN_CHECK 0
 #  else
 #    define XXH_FORCE_ALIGN_CHECK 1
 #  endif
 #endif
 
 
 /* *************************************
 *  Includes & Memory related functions
 ***************************************/
 /* Modify the local functions below should you wish to use some other memory routines */
 /* for malloc(), free() */
 #include 
 static void* XXH_malloc(size_t s) { return malloc(s); }
 static void  XXH_free  (void* p)  { free(p); }
 /* for memcpy() */
 #include 
 static void* XXH_memcpy(void* dest, const void* src, size_t size) { return memcpy(dest,src,size); }
 
 #ifndef XXH_STATIC_LINKING_ONLY
 #  define XXH_STATIC_LINKING_ONLY
 #endif
 #include "xxhash.h"
 
 
 /* *************************************
 *  Compiler Specific Options
 ***************************************/
 #if defined (__GNUC__) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
 #  define INLINE_KEYWORD inline
 #else
 #  define INLINE_KEYWORD
 #endif
 
 #if defined(__GNUC__)
 #  define FORCE_INLINE_ATTR __attribute__((always_inline))
 #elif defined(_MSC_VER)
 #  define FORCE_INLINE_ATTR __forceinline
 #else
 #  define FORCE_INLINE_ATTR
 #endif
 
 #define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR
 
 
 #ifdef _MSC_VER
 #  pragma warning(disable : 4127)      /* disable: C4127: conditional expression is constant */
 #endif
 
 
 /* *************************************
 *  Basic Types
 ***************************************/
 #ifndef MEM_MODULE
 # define MEM_MODULE
 # if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
 #   include 
     typedef uint8_t  BYTE;
     typedef uint16_t U16;
     typedef uint32_t U32;
     typedef  int32_t S32;
     typedef uint64_t U64;
 #  else
     typedef unsigned char      BYTE;
     typedef unsigned short     U16;
     typedef unsigned int       U32;
     typedef   signed int       S32;
     typedef unsigned long long U64;   /* if your compiler doesn't support unsigned long long, replace by another 64-bit type here. Note that xxhash.h will also need to be updated. */
 #  endif
 #endif
 
 
 #if (defined(XXH_FORCE_MEMORY_ACCESS) && (XXH_FORCE_MEMORY_ACCESS==2))
 
 /* Force direct memory access. Only works on CPU which support unaligned memory access in hardware */
 static U32 XXH_read32(const void* memPtr) { return *(const U32*) memPtr; }
 static U64 XXH_read64(const void* memPtr) { return *(const U64*) memPtr; }
 
 #elif (defined(XXH_FORCE_MEMORY_ACCESS) && (XXH_FORCE_MEMORY_ACCESS==1))
 
 /* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
 /* currently only defined for gcc and icc */
 typedef union { U32 u32; U64 u64; } __attribute__((packed)) unalign;
 
 static U32 XXH_read32(const void* ptr) { return ((const unalign*)ptr)->u32; }
 static U64 XXH_read64(const void* ptr) { return ((const unalign*)ptr)->u64; }
 
 #else
 
 /* portable and safe solution. Generally efficient.
  * see : http://stackoverflow.com/a/32095106/646947
  */
 
 static U32 XXH_read32(const void* memPtr)
 {
     U32 val;
     memcpy(&val, memPtr, sizeof(val));
     return val;
 }
 
 static U64 XXH_read64(const void* memPtr)
 {
     U64 val;
     memcpy(&val, memPtr, sizeof(val));
     return val;
 }
 
 #endif   /* XXH_FORCE_DIRECT_MEMORY_ACCESS */
 
 
 /* ****************************************
 *  Compiler-specific Functions and Macros
 ******************************************/
 #define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
 
 /* Note : although _rotl exists for minGW (GCC under windows), performance seems poor */
 #if defined(_MSC_VER)
 #  define XXH_rotl32(x,r) _rotl(x,r)
 #  define XXH_rotl64(x,r) _rotl64(x,r)
 #else
 #  define XXH_rotl32(x,r) ((x << r) | (x >> (32 - r)))
 #  define XXH_rotl64(x,r) ((x << r) | (x >> (64 - r)))
 #endif
 
 #if defined(_MSC_VER)     /* Visual Studio */
 #  define XXH_swap32 _byteswap_ulong
 #  define XXH_swap64 _byteswap_uint64
-#elif (GCC_VERSION >= 403 && !defined(__riscv))
+#elif GCC_VERSION >= 403
 #  define XXH_swap32 __builtin_bswap32
 #  define XXH_swap64 __builtin_bswap64
 #else
 static U32 XXH_swap32 (U32 x)
 {
     return  ((x << 24) & 0xff000000 ) |
             ((x <<  8) & 0x00ff0000 ) |
             ((x >>  8) & 0x0000ff00 ) |
             ((x >> 24) & 0x000000ff );
 }
 static U64 XXH_swap64 (U64 x)
 {
     return  ((x << 56) & 0xff00000000000000ULL) |
             ((x << 40) & 0x00ff000000000000ULL) |
             ((x << 24) & 0x0000ff0000000000ULL) |
             ((x << 8)  & 0x000000ff00000000ULL) |
             ((x >> 8)  & 0x00000000ff000000ULL) |
             ((x >> 24) & 0x0000000000ff0000ULL) |
             ((x >> 40) & 0x000000000000ff00ULL) |
             ((x >> 56) & 0x00000000000000ffULL);
 }
 #endif
 
 
 /* *************************************
 *  Architecture Macros
 ***************************************/
 typedef enum { XXH_bigEndian=0, XXH_littleEndian=1 } XXH_endianess;
 
 /* XXH_CPU_LITTLE_ENDIAN can be defined externally, for example on the compiler command line */
 #ifndef XXH_CPU_LITTLE_ENDIAN
     static const int g_one = 1;
 #   define XXH_CPU_LITTLE_ENDIAN   (*(const char*)(&g_one))
 #endif
 
 
 /* ***************************
 *  Memory reads
 *****************************/
 typedef enum { XXH_aligned, XXH_unaligned } XXH_alignment;
 
 FORCE_INLINE_TEMPLATE U32 XXH_readLE32_align(const void* ptr, XXH_endianess endian, XXH_alignment align)
 {
     if (align==XXH_unaligned)
         return endian==XXH_littleEndian ? XXH_read32(ptr) : XXH_swap32(XXH_read32(ptr));
     else
         return endian==XXH_littleEndian ? *(const U32*)ptr : XXH_swap32(*(const U32*)ptr);
 }
 
 FORCE_INLINE_TEMPLATE U32 XXH_readLE32(const void* ptr, XXH_endianess endian)
 {
     return XXH_readLE32_align(ptr, endian, XXH_unaligned);
 }
 
 static U32 XXH_readBE32(const void* ptr)
 {
     return XXH_CPU_LITTLE_ENDIAN ? XXH_swap32(XXH_read32(ptr)) : XXH_read32(ptr);
 }
 
 FORCE_INLINE_TEMPLATE U64 XXH_readLE64_align(const void* ptr, XXH_endianess endian, XXH_alignment align)
 {
     if (align==XXH_unaligned)
         return endian==XXH_littleEndian ? XXH_read64(ptr) : XXH_swap64(XXH_read64(ptr));
     else
         return endian==XXH_littleEndian ? *(const U64*)ptr : XXH_swap64(*(const U64*)ptr);
 }
 
 FORCE_INLINE_TEMPLATE U64 XXH_readLE64(const void* ptr, XXH_endianess endian)
 {
     return XXH_readLE64_align(ptr, endian, XXH_unaligned);
 }
 
 static U64 XXH_readBE64(const void* ptr)
 {
     return XXH_CPU_LITTLE_ENDIAN ? XXH_swap64(XXH_read64(ptr)) : XXH_read64(ptr);
 }
 
 
 /* *************************************
 *  Macros
 ***************************************/
 #define XXH_STATIC_ASSERT(c)   { enum { XXH_static_assert = 1/(int)(!!(c)) }; }    /* use only *after* variable declarations */
 
 
 /* *************************************
 *  Constants
 ***************************************/
 static const U32 PRIME32_1 = 2654435761U;
 static const U32 PRIME32_2 = 2246822519U;
 static const U32 PRIME32_3 = 3266489917U;
 static const U32 PRIME32_4 =  668265263U;
 static const U32 PRIME32_5 =  374761393U;
 
 static const U64 PRIME64_1 = 11400714785074694791ULL;
 static const U64 PRIME64_2 = 14029467366897019727ULL;
 static const U64 PRIME64_3 =  1609587929392839161ULL;
 static const U64 PRIME64_4 =  9650029242287828579ULL;
 static const U64 PRIME64_5 =  2870177450012600261ULL;
 
 XXH_PUBLIC_API unsigned XXH_versionNumber (void) { return XXH_VERSION_NUMBER; }
 
 
 /* **************************
 *  Utils
 ****************************/
 XXH_PUBLIC_API void XXH32_copyState(XXH32_state_t* restrict dstState, const XXH32_state_t* restrict srcState)
 {
     memcpy(dstState, srcState, sizeof(*dstState));
 }
 
 XXH_PUBLIC_API void XXH64_copyState(XXH64_state_t* restrict dstState, const XXH64_state_t* restrict srcState)
 {
     memcpy(dstState, srcState, sizeof(*dstState));
 }
 
 
 /* ***************************
 *  Simple Hash Functions
 *****************************/
 
 static U32 XXH32_round(U32 seed, U32 input)
 {
     seed += input * PRIME32_2;
     seed  = XXH_rotl32(seed, 13);
     seed *= PRIME32_1;
     return seed;
 }
 
 FORCE_INLINE_TEMPLATE U32 XXH32_endian_align(const void* input, size_t len, U32 seed, XXH_endianess endian, XXH_alignment align)
 {
     const BYTE* p = (const BYTE*)input;
     const BYTE* bEnd = p + len;
     U32 h32;
 #define XXH_get32bits(p) XXH_readLE32_align(p, endian, align)
 
 #ifdef XXH_ACCEPT_NULL_INPUT_POINTER
     if (p==NULL) {
         len=0;
         bEnd=p=(const BYTE*)(size_t)16;
     }
 #endif
 
     if (len>=16) {
         const BYTE* const limit = bEnd - 16;
         U32 v1 = seed + PRIME32_1 + PRIME32_2;
         U32 v2 = seed + PRIME32_2;
         U32 v3 = seed + 0;
         U32 v4 = seed - PRIME32_1;
 
         do {
             v1 = XXH32_round(v1, XXH_get32bits(p)); p+=4;
             v2 = XXH32_round(v2, XXH_get32bits(p)); p+=4;
             v3 = XXH32_round(v3, XXH_get32bits(p)); p+=4;
             v4 = XXH32_round(v4, XXH_get32bits(p)); p+=4;
         } while (p<=limit);
 
         h32 = XXH_rotl32(v1, 1) + XXH_rotl32(v2, 7) + XXH_rotl32(v3, 12) + XXH_rotl32(v4, 18);
     } else {
         h32  = seed + PRIME32_5;
     }
 
     h32 += (U32) len;
 
     while (p+4<=bEnd) {
         h32 += XXH_get32bits(p) * PRIME32_3;
         h32  = XXH_rotl32(h32, 17) * PRIME32_4 ;
         p+=4;
     }
 
     while (p> 15;
     h32 *= PRIME32_2;
     h32 ^= h32 >> 13;
     h32 *= PRIME32_3;
     h32 ^= h32 >> 16;
 
     return h32;
 }
 
 
 XXH_PUBLIC_API unsigned int XXH32 (const void* input, size_t len, unsigned int seed)
 {
 #if 0
     /* Simple version, good for code maintenance, but unfortunately slow for small inputs */
     XXH32_CREATESTATE_STATIC(state);
     XXH32_reset(state, seed);
     XXH32_update(state, input, len);
     return XXH32_digest(state);
 #else
     XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
 
     if (XXH_FORCE_ALIGN_CHECK) {
         if ((((size_t)input) & 3) == 0) {   /* Input is 4-bytes aligned, leverage the speed benefit */
             if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
                 return XXH32_endian_align(input, len, seed, XXH_littleEndian, XXH_aligned);
             else
                 return XXH32_endian_align(input, len, seed, XXH_bigEndian, XXH_aligned);
     }   }
 
     if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
         return XXH32_endian_align(input, len, seed, XXH_littleEndian, XXH_unaligned);
     else
         return XXH32_endian_align(input, len, seed, XXH_bigEndian, XXH_unaligned);
 #endif
 }
 
 
 static U64 XXH64_round(U64 acc, U64 input)
 {
     acc += input * PRIME64_2;
     acc  = XXH_rotl64(acc, 31);
     acc *= PRIME64_1;
     return acc;
 }
 
 static U64 XXH64_mergeRound(U64 acc, U64 val)
 {
     val  = XXH64_round(0, val);
     acc ^= val;
     acc  = acc * PRIME64_1 + PRIME64_4;
     return acc;
 }
 
 FORCE_INLINE_TEMPLATE U64 XXH64_endian_align(const void* input, size_t len, U64 seed, XXH_endianess endian, XXH_alignment align)
 {
     const BYTE* p = (const BYTE*)input;
     const BYTE* const bEnd = p + len;
     U64 h64;
 #define XXH_get64bits(p) XXH_readLE64_align(p, endian, align)
 
 #ifdef XXH_ACCEPT_NULL_INPUT_POINTER
     if (p==NULL) {
         len=0;
         bEnd=p=(const BYTE*)(size_t)32;
     }
 #endif
 
     if (len>=32) {
         const BYTE* const limit = bEnd - 32;
         U64 v1 = seed + PRIME64_1 + PRIME64_2;
         U64 v2 = seed + PRIME64_2;
         U64 v3 = seed + 0;
         U64 v4 = seed - PRIME64_1;
 
         do {
             v1 = XXH64_round(v1, XXH_get64bits(p)); p+=8;
             v2 = XXH64_round(v2, XXH_get64bits(p)); p+=8;
             v3 = XXH64_round(v3, XXH_get64bits(p)); p+=8;
             v4 = XXH64_round(v4, XXH_get64bits(p)); p+=8;
         } while (p<=limit);
 
         h64 = XXH_rotl64(v1, 1) + XXH_rotl64(v2, 7) + XXH_rotl64(v3, 12) + XXH_rotl64(v4, 18);
         h64 = XXH64_mergeRound(h64, v1);
         h64 = XXH64_mergeRound(h64, v2);
         h64 = XXH64_mergeRound(h64, v3);
         h64 = XXH64_mergeRound(h64, v4);
 
     } else {
         h64  = seed + PRIME64_5;
     }
 
     h64 += (U64) len;
 
     while (p+8<=bEnd) {
         U64 const k1 = XXH64_round(0, XXH_get64bits(p));
         h64 ^= k1;
         h64  = XXH_rotl64(h64,27) * PRIME64_1 + PRIME64_4;
         p+=8;
     }
 
     if (p+4<=bEnd) {
         h64 ^= (U64)(XXH_get32bits(p)) * PRIME64_1;
         h64 = XXH_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
         p+=4;
     }
 
     while (p> 33;
     h64 *= PRIME64_2;
     h64 ^= h64 >> 29;
     h64 *= PRIME64_3;
     h64 ^= h64 >> 32;
 
     return h64;
 }
 
 
 XXH_PUBLIC_API unsigned long long XXH64 (const void* input, size_t len, unsigned long long seed)
 {
 #if 0
     /* Simple version, good for code maintenance, but unfortunately slow for small inputs */
     XXH64_CREATESTATE_STATIC(state);
     XXH64_reset(state, seed);
     XXH64_update(state, input, len);
     return XXH64_digest(state);
 #else
     XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
 
     if (XXH_FORCE_ALIGN_CHECK) {
         if ((((size_t)input) & 7)==0) {  /* Input is aligned, let's leverage the speed advantage */
             if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
                 return XXH64_endian_align(input, len, seed, XXH_littleEndian, XXH_aligned);
             else
                 return XXH64_endian_align(input, len, seed, XXH_bigEndian, XXH_aligned);
     }   }
 
     if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
         return XXH64_endian_align(input, len, seed, XXH_littleEndian, XXH_unaligned);
     else
         return XXH64_endian_align(input, len, seed, XXH_bigEndian, XXH_unaligned);
 #endif
 }
 
 
 /* **************************************************
 *  Advanced Hash Functions
 ****************************************************/
 
 XXH_PUBLIC_API XXH32_state_t* XXH32_createState(void)
 {
     return (XXH32_state_t*)XXH_malloc(sizeof(XXH32_state_t));
 }
 XXH_PUBLIC_API XXH_errorcode XXH32_freeState(XXH32_state_t* statePtr)
 {
     XXH_free(statePtr);
     return XXH_OK;
 }
 
 XXH_PUBLIC_API XXH64_state_t* XXH64_createState(void)
 {
     return (XXH64_state_t*)XXH_malloc(sizeof(XXH64_state_t));
 }
 XXH_PUBLIC_API XXH_errorcode XXH64_freeState(XXH64_state_t* statePtr)
 {
     XXH_free(statePtr);
     return XXH_OK;
 }
 
 
 /*** Hash feed ***/
 
 XXH_PUBLIC_API XXH_errorcode XXH32_reset(XXH32_state_t* statePtr, unsigned int seed)
 {
     XXH32_state_t state;   /* using a local state to memcpy() in order to avoid strict-aliasing warnings */
     memset(&state, 0, sizeof(state)-4);   /* do not write into reserved, for future removal */
     state.v1 = seed + PRIME32_1 + PRIME32_2;
     state.v2 = seed + PRIME32_2;
     state.v3 = seed + 0;
     state.v4 = seed - PRIME32_1;
     memcpy(statePtr, &state, sizeof(state));
     return XXH_OK;
 }
 
 
 XXH_PUBLIC_API XXH_errorcode XXH64_reset(XXH64_state_t* statePtr, unsigned long long seed)
 {
     XXH64_state_t state;   /* using a local state to memcpy() in order to avoid strict-aliasing warnings */
     memset(&state, 0, sizeof(state)-8);   /* do not write into reserved, for future removal */
     state.v1 = seed + PRIME64_1 + PRIME64_2;
     state.v2 = seed + PRIME64_2;
     state.v3 = seed + 0;
     state.v4 = seed - PRIME64_1;
     memcpy(statePtr, &state, sizeof(state));
     return XXH_OK;
 }
 
 
 FORCE_INLINE_TEMPLATE XXH_errorcode XXH32_update_endian (XXH32_state_t* state, const void* input, size_t len, XXH_endianess endian)
 {
     const BYTE* p = (const BYTE*)input;
     const BYTE* const bEnd = p + len;
 
 #ifdef XXH_ACCEPT_NULL_INPUT_POINTER
     if (input==NULL) return XXH_ERROR;
 #endif
 
     state->total_len_32 += (unsigned)len;
     state->large_len |= (len>=16) | (state->total_len_32>=16);
 
     if (state->memsize + len < 16)  {   /* fill in tmp buffer */
         XXH_memcpy((BYTE*)(state->mem32) + state->memsize, input, len);
         state->memsize += (unsigned)len;
         return XXH_OK;
     }
 
     if (state->memsize) {   /* some data left from previous update */
         XXH_memcpy((BYTE*)(state->mem32) + state->memsize, input, 16-state->memsize);
         {   const U32* p32 = state->mem32;
             state->v1 = XXH32_round(state->v1, XXH_readLE32(p32, endian)); p32++;
             state->v2 = XXH32_round(state->v2, XXH_readLE32(p32, endian)); p32++;
             state->v3 = XXH32_round(state->v3, XXH_readLE32(p32, endian)); p32++;
             state->v4 = XXH32_round(state->v4, XXH_readLE32(p32, endian)); p32++;
         }
         p += 16-state->memsize;
         state->memsize = 0;
     }
 
     if (p <= bEnd-16) {
         const BYTE* const limit = bEnd - 16;
         U32 v1 = state->v1;
         U32 v2 = state->v2;
         U32 v3 = state->v3;
         U32 v4 = state->v4;
 
         do {
             v1 = XXH32_round(v1, XXH_readLE32(p, endian)); p+=4;
             v2 = XXH32_round(v2, XXH_readLE32(p, endian)); p+=4;
             v3 = XXH32_round(v3, XXH_readLE32(p, endian)); p+=4;
             v4 = XXH32_round(v4, XXH_readLE32(p, endian)); p+=4;
         } while (p<=limit);
 
         state->v1 = v1;
         state->v2 = v2;
         state->v3 = v3;
         state->v4 = v4;
     }
 
     if (p < bEnd) {
         XXH_memcpy(state->mem32, p, (size_t)(bEnd-p));
         state->memsize = (unsigned)(bEnd-p);
     }
 
     return XXH_OK;
 }
 
 XXH_PUBLIC_API XXH_errorcode XXH32_update (XXH32_state_t* state_in, const void* input, size_t len)
 {
     XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
 
     if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
         return XXH32_update_endian(state_in, input, len, XXH_littleEndian);
     else
         return XXH32_update_endian(state_in, input, len, XXH_bigEndian);
 }
 
 
 
 FORCE_INLINE_TEMPLATE U32 XXH32_digest_endian (const XXH32_state_t* state, XXH_endianess endian)
 {
     const BYTE * p = (const BYTE*)state->mem32;
     const BYTE* const bEnd = (const BYTE*)(state->mem32) + state->memsize;
     U32 h32;
 
     if (state->large_len) {
         h32 = XXH_rotl32(state->v1, 1) + XXH_rotl32(state->v2, 7) + XXH_rotl32(state->v3, 12) + XXH_rotl32(state->v4, 18);
     } else {
         h32 = state->v3 /* == seed */ + PRIME32_5;
     }
 
     h32 += state->total_len_32;
 
     while (p+4<=bEnd) {
         h32 += XXH_readLE32(p, endian) * PRIME32_3;
         h32  = XXH_rotl32(h32, 17) * PRIME32_4;
         p+=4;
     }
 
     while (p> 15;
     h32 *= PRIME32_2;
     h32 ^= h32 >> 13;
     h32 *= PRIME32_3;
     h32 ^= h32 >> 16;
 
     return h32;
 }
 
 
 XXH_PUBLIC_API unsigned int XXH32_digest (const XXH32_state_t* state_in)
 {
     XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
 
     if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
         return XXH32_digest_endian(state_in, XXH_littleEndian);
     else
         return XXH32_digest_endian(state_in, XXH_bigEndian);
 }
 
 
 
 /* **** XXH64 **** */
 
 FORCE_INLINE_TEMPLATE XXH_errorcode XXH64_update_endian (XXH64_state_t* state, const void* input, size_t len, XXH_endianess endian)
 {
     const BYTE* p = (const BYTE*)input;
     const BYTE* const bEnd = p + len;
 
 #ifdef XXH_ACCEPT_NULL_INPUT_POINTER
     if (input==NULL) return XXH_ERROR;
 #endif
 
     state->total_len += len;
 
     if (state->memsize + len < 32) {  /* fill in tmp buffer */
         XXH_memcpy(((BYTE*)state->mem64) + state->memsize, input, len);
         state->memsize += (U32)len;
         return XXH_OK;
     }
 
     if (state->memsize) {   /* tmp buffer is full */
         XXH_memcpy(((BYTE*)state->mem64) + state->memsize, input, 32-state->memsize);
         state->v1 = XXH64_round(state->v1, XXH_readLE64(state->mem64+0, endian));
         state->v2 = XXH64_round(state->v2, XXH_readLE64(state->mem64+1, endian));
         state->v3 = XXH64_round(state->v3, XXH_readLE64(state->mem64+2, endian));
         state->v4 = XXH64_round(state->v4, XXH_readLE64(state->mem64+3, endian));
         p += 32-state->memsize;
         state->memsize = 0;
     }
 
     if (p+32 <= bEnd) {
         const BYTE* const limit = bEnd - 32;
         U64 v1 = state->v1;
         U64 v2 = state->v2;
         U64 v3 = state->v3;
         U64 v4 = state->v4;
 
         do {
             v1 = XXH64_round(v1, XXH_readLE64(p, endian)); p+=8;
             v2 = XXH64_round(v2, XXH_readLE64(p, endian)); p+=8;
             v3 = XXH64_round(v3, XXH_readLE64(p, endian)); p+=8;
             v4 = XXH64_round(v4, XXH_readLE64(p, endian)); p+=8;
         } while (p<=limit);
 
         state->v1 = v1;
         state->v2 = v2;
         state->v3 = v3;
         state->v4 = v4;
     }
 
     if (p < bEnd) {
         XXH_memcpy(state->mem64, p, (size_t)(bEnd-p));
         state->memsize = (unsigned)(bEnd-p);
     }
 
     return XXH_OK;
 }
 
 XXH_PUBLIC_API XXH_errorcode XXH64_update (XXH64_state_t* state_in, const void* input, size_t len)
 {
     XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
 
     if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
         return XXH64_update_endian(state_in, input, len, XXH_littleEndian);
     else
         return XXH64_update_endian(state_in, input, len, XXH_bigEndian);
 }
 
 
 
 FORCE_INLINE_TEMPLATE U64 XXH64_digest_endian (const XXH64_state_t* state, XXH_endianess endian)
 {
     const BYTE * p = (const BYTE*)state->mem64;
     const BYTE* const bEnd = (const BYTE*)state->mem64 + state->memsize;
     U64 h64;
 
     if (state->total_len >= 32) {
         U64 const v1 = state->v1;
         U64 const v2 = state->v2;
         U64 const v3 = state->v3;
         U64 const v4 = state->v4;
 
         h64 = XXH_rotl64(v1, 1) + XXH_rotl64(v2, 7) + XXH_rotl64(v3, 12) + XXH_rotl64(v4, 18);
         h64 = XXH64_mergeRound(h64, v1);
         h64 = XXH64_mergeRound(h64, v2);
         h64 = XXH64_mergeRound(h64, v3);
         h64 = XXH64_mergeRound(h64, v4);
     } else {
         h64  = state->v3 + PRIME64_5;
     }
 
     h64 += (U64) state->total_len;
 
     while (p+8<=bEnd) {
         U64 const k1 = XXH64_round(0, XXH_readLE64(p, endian));
         h64 ^= k1;
         h64  = XXH_rotl64(h64,27) * PRIME64_1 + PRIME64_4;
         p+=8;
     }
 
     if (p+4<=bEnd) {
         h64 ^= (U64)(XXH_readLE32(p, endian)) * PRIME64_1;
         h64  = XXH_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
         p+=4;
     }
 
     while (p> 33;
     h64 *= PRIME64_2;
     h64 ^= h64 >> 29;
     h64 *= PRIME64_3;
     h64 ^= h64 >> 32;
 
     return h64;
 }
 
 
 XXH_PUBLIC_API unsigned long long XXH64_digest (const XXH64_state_t* state_in)
 {
     XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
 
     if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
         return XXH64_digest_endian(state_in, XXH_littleEndian);
     else
         return XXH64_digest_endian(state_in, XXH_bigEndian);
 }
 
 
 /* **************************
 *  Canonical representation
 ****************************/
 
 /*! Default XXH result types are basic unsigned 32 and 64 bits.
 *   The canonical representation follows human-readable write convention, aka big-endian (large digits first).
 *   These functions allow transformation of hash result into and from its canonical format.
 *   This way, hash values can be written into a file or buffer, and remain comparable across different systems and programs.
 */
 
 XXH_PUBLIC_API void XXH32_canonicalFromHash(XXH32_canonical_t* dst, XXH32_hash_t hash)
 {
     XXH_STATIC_ASSERT(sizeof(XXH32_canonical_t) == sizeof(XXH32_hash_t));
     if (XXH_CPU_LITTLE_ENDIAN) hash = XXH_swap32(hash);
     memcpy(dst, &hash, sizeof(*dst));
 }
 
 XXH_PUBLIC_API void XXH64_canonicalFromHash(XXH64_canonical_t* dst, XXH64_hash_t hash)
 {
     XXH_STATIC_ASSERT(sizeof(XXH64_canonical_t) == sizeof(XXH64_hash_t));
     if (XXH_CPU_LITTLE_ENDIAN) hash = XXH_swap64(hash);
     memcpy(dst, &hash, sizeof(*dst));
 }
 
 XXH_PUBLIC_API XXH32_hash_t XXH32_hashFromCanonical(const XXH32_canonical_t* src)
 {
     return XXH_readBE32(src);
 }
 
 XXH_PUBLIC_API XXH64_hash_t XXH64_hashFromCanonical(const XXH64_canonical_t* src)
 {
     return XXH_readBE64(src);
 }
Index: head/sys/contrib/zstd/lib/common/zstd_common.c
===================================================================
--- head/sys/contrib/zstd/lib/common/zstd_common.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/common/zstd_common.c	(revision 330894)
@@ -1,80 +1,86 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 
 
 /*-*************************************
 *  Dependencies
 ***************************************/
 #include       /* malloc, calloc, free */
 #include       /* memset */
 #include "error_private.h"
 #include "zstd_internal.h"
 
 
 /*-****************************************
 *  Version
 ******************************************/
 unsigned ZSTD_versionNumber(void) { return ZSTD_VERSION_NUMBER; }
 
 const char* ZSTD_versionString(void) { return ZSTD_VERSION_STRING; }
 
 
 /*-****************************************
 *  ZSTD Error Management
 ******************************************/
 /*! ZSTD_isError() :
-*   tells if a return value is an error code */
+ *  tells if a return value is an error code */
 unsigned ZSTD_isError(size_t code) { return ERR_isError(code); }
 
 /*! ZSTD_getErrorName() :
-*   provides error code string from function result (useful for debugging) */
+ *  provides error code string from function result (useful for debugging) */
 const char* ZSTD_getErrorName(size_t code) { return ERR_getErrorName(code); }
 
 /*! ZSTD_getError() :
-*   convert a `size_t` function result into a proper ZSTD_errorCode enum */
+ *  convert a `size_t` function result into a proper ZSTD_errorCode enum */
 ZSTD_ErrorCode ZSTD_getErrorCode(size_t code) { return ERR_getErrorCode(code); }
 
 /*! ZSTD_getErrorString() :
-*   provides error code string from enum */
+ *  provides error code string from enum */
 const char* ZSTD_getErrorString(ZSTD_ErrorCode code) { return ERR_getErrorString(code); }
+
+/*! g_debuglog_enable :
+ *  turn on/off debug traces (global switch) */
+#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG >= 2)
+int g_debuglog_enable = 1;
+#endif
 
 
 /*=**************************************************************
 *  Custom allocator
 ****************************************************************/
 void* ZSTD_malloc(size_t size, ZSTD_customMem customMem)
 {
     if (customMem.customAlloc)
         return customMem.customAlloc(customMem.opaque, size);
     return malloc(size);
 }
 
 void* ZSTD_calloc(size_t size, ZSTD_customMem customMem)
 {
     if (customMem.customAlloc) {
         /* calloc implemented as malloc+memset;
          * not as efficient as calloc, but next best guess for custom malloc */
         void* const ptr = customMem.customAlloc(customMem.opaque, size);
         memset(ptr, 0, size);
         return ptr;
     }
     return calloc(1, size);
 }
 
 void ZSTD_free(void* ptr, ZSTD_customMem customMem)
 {
     if (ptr!=NULL) {
         if (customMem.customFree)
             customMem.customFree(customMem.opaque, ptr);
         else
             free(ptr);
     }
 }
Index: head/sys/contrib/zstd/lib/common/zstd_internal.h
===================================================================
--- head/sys/contrib/zstd/lib/common/zstd_internal.h	(revision 330893)
+++ head/sys/contrib/zstd/lib/common/zstd_internal.h	(revision 330894)
@@ -1,409 +1,291 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 #ifndef ZSTD_CCOMMON_H_MODULE
 #define ZSTD_CCOMMON_H_MODULE
 
+/* this module contains definitions which must be identical
+ * across compression, decompression and dictBuilder.
+ * It also contains a few functions useful to at least 2 of them
+ * and which benefit from being inlined */
 
 /*-*************************************
 *  Dependencies
 ***************************************/
 #include "compiler.h"
 #include "mem.h"
 #include "error_private.h"
 #define ZSTD_STATIC_LINKING_ONLY
 #include "zstd.h"
 #define FSE_STATIC_LINKING_ONLY
 #include "fse.h"
 #define HUF_STATIC_LINKING_ONLY
 #include "huf.h"
 #ifndef XXH_STATIC_LINKING_ONLY
 #  define XXH_STATIC_LINKING_ONLY  /* XXH64_state_t */
 #endif
 #include "xxhash.h"                /* XXH_reset, update, digest */
 
 
 #if defined (__cplusplus)
 extern "C" {
 #endif
 
 
 /*-*************************************
 *  Debug
 ***************************************/
 #if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=1)
 #  include 
 #else
 #  ifndef assert
 #    define assert(condition) ((void)0)
 #  endif
 #endif
 
 #define ZSTD_STATIC_ASSERT(c) { enum { ZSTD_static_assert = 1/(int)(!!(c)) }; }
 
 #if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=2)
 #  include 
+extern int g_debuglog_enable;
 /* recommended values for ZSTD_DEBUG display levels :
  * 1 : no display, enables assert() only
- * 2 : reserved for currently active debugging path
- * 3 : events once per object lifetime (CCtx, CDict)
+ * 2 : reserved for currently active debug path
+ * 3 : events once per object lifetime (CCtx, CDict, etc.)
  * 4 : events once per frame
  * 5 : events once per block
  * 6 : events once per sequence (*very* verbose) */
-#  define DEBUGLOG(l, ...) {                         \
-                if (l<=ZSTD_DEBUG) {                 \
-                    fprintf(stderr, __FILE__ ": ");  \
-                    fprintf(stderr, __VA_ARGS__);    \
-                    fprintf(stderr, " \n");          \
+#  define RAWLOG(l, ...) {                                      \
+                if ((g_debuglog_enable) & (l<=ZSTD_DEBUG)) {    \
+                    fprintf(stderr, __VA_ARGS__);               \
             }   }
+#  define DEBUGLOG(l, ...) {                                    \
+                if ((g_debuglog_enable) & (l<=ZSTD_DEBUG)) {    \
+                    fprintf(stderr, __FILE__ ": " __VA_ARGS__); \
+                    fprintf(stderr, " \n");                     \
+            }   }
 #else
-#  define DEBUGLOG(l, ...)      {}    /* disabled */
+#  define RAWLOG(l, ...)      {}    /* disabled */
+#  define DEBUGLOG(l, ...)    {}    /* disabled */
 #endif
 
 
 /*-*************************************
 *  shared macros
 ***************************************/
 #undef MIN
 #undef MAX
 #define MIN(a,b) ((a)<(b) ? (a) : (b))
 #define MAX(a,b) ((a)>(b) ? (a) : (b))
 #define CHECK_F(f) { size_t const errcod = f; if (ERR_isError(errcod)) return errcod; }  /* check and Forward error code */
 #define CHECK_E(f, e) { size_t const errcod = f; if (ERR_isError(errcod)) return ERROR(e); }  /* check and send Error code */
 
 
 /*-*************************************
 *  Common constants
 ***************************************/
 #define ZSTD_OPT_NUM    (1<<12)
 
 #define ZSTD_REP_NUM      3                 /* number of repcodes */
-#define ZSTD_REP_CHECK    (ZSTD_REP_NUM)    /* number of repcodes to check by the optimal parser */
 #define ZSTD_REP_MOVE     (ZSTD_REP_NUM-1)
-#define ZSTD_REP_MOVE_OPT (ZSTD_REP_NUM)
 static const U32 repStartValue[ZSTD_REP_NUM] = { 1, 4, 8 };
 
 #define KB *(1 <<10)
 #define MB *(1 <<20)
 #define GB *(1U<<30)
 
 #define BIT7 128
 #define BIT6  64
 #define BIT5  32
 #define BIT4  16
 #define BIT1   2
 #define BIT0   1
 
 #define ZSTD_WINDOWLOG_ABSOLUTEMIN 10
 #define ZSTD_WINDOWLOG_DEFAULTMAX 27 /* Default maximum allowed window log */
 static const size_t ZSTD_fcs_fieldSize[4] = { 0, 2, 4, 8 };
 static const size_t ZSTD_did_fieldSize[4] = { 0, 1, 2, 4 };
 
 #define ZSTD_FRAMEIDSIZE 4
 static const size_t ZSTD_frameIdSize = ZSTD_FRAMEIDSIZE;  /* magic number size */
 
 #define ZSTD_BLOCKHEADERSIZE 3   /* C standard doesn't allow `static const` variable to be init using another `static const` variable */
 static const size_t ZSTD_blockHeaderSize = ZSTD_BLOCKHEADERSIZE;
 typedef enum { bt_raw, bt_rle, bt_compressed, bt_reserved } blockType_e;
 
 #define MIN_SEQUENCES_SIZE 1 /* nbSeq==0 */
 #define MIN_CBLOCK_SIZE (1 /*litCSize*/ + 1 /* RLE or RAW */ + MIN_SEQUENCES_SIZE /* nbSeq==0 */)   /* for a non-null block */
 
 #define HufLog 12
 typedef enum { set_basic, set_rle, set_compressed, set_repeat } symbolEncodingType_e;
 
 #define LONGNBSEQ 0x7F00
 
 #define MINMATCH 3
 
 #define Litbits  8
 #define MaxLit ((1<= 3) && __has_builtin(__builtin_clz)   /* GCC Intrinsic */
         return 31 - __builtin_clz(val);
 #   else   /* Software version */
-        static const int DeBruijnClz[32] = { 0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30, 8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31 };
+        static const U32 DeBruijnClz[32] = { 0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30, 8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31 };
         U32 v = val;
-        int r;
         v |= v >> 1;
         v |= v >> 2;
         v |= v >> 4;
         v |= v >> 8;
         v |= v >> 16;
-        r = DeBruijnClz[(U32)(v * 0x07C4ACDDU) >> 27];
-        return r;
+        return DeBruijnClz[(v * 0x07C4ACDDU) >> 27];
 #   endif
     }
 }
 
 
-/* hidden functions */
-
 /* ZSTD_invalidateRepCodes() :
  * ensures next compression will not use repcodes from previous block.
  * Note : only works with regular variant;
  *        do not use with extDict variant ! */
-void ZSTD_invalidateRepCodes(ZSTD_CCtx* cctx);
+void ZSTD_invalidateRepCodes(ZSTD_CCtx* cctx);   /* zstdmt, adaptive_compression (shouldn't get this definition from here) */
 
 
-/*! ZSTD_initCStream_internal() :
- *  Private use only. Init streaming operation.
- *  expects params to be valid.
- *  must receive dict, or cdict, or none, but not both.
- *  @return : 0, or an error code */
-size_t ZSTD_initCStream_internal(ZSTD_CStream* zcs,
-                     const void* dict, size_t dictSize,
-                     const ZSTD_CDict* cdict,
-                     ZSTD_CCtx_params  params, unsigned long long pledgedSrcSize);
-
-/*! ZSTD_compressStream_generic() :
- *  Private use only. To be called from zstdmt_compress.c in single-thread mode. */
-size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
-                                   ZSTD_outBuffer* output,
-                                   ZSTD_inBuffer* input,
-                                   ZSTD_EndDirective const flushMode);
-
-/*! ZSTD_getCParamsFromCDict() :
- *  as the name implies */
-ZSTD_compressionParameters ZSTD_getCParamsFromCDict(const ZSTD_CDict* cdict);
-
-/* ZSTD_compressBegin_advanced_internal() :
- * Private use only. To be called from zstdmt_compress.c. */
-size_t ZSTD_compressBegin_advanced_internal(ZSTD_CCtx* cctx,
-                                    const void* dict, size_t dictSize,
-                                    ZSTD_dictMode_e dictMode,
-                                    ZSTD_CCtx_params params,
-                                    unsigned long long pledgedSrcSize);
-
-/* ZSTD_compress_advanced_internal() :
- * Private use only. To be called from zstdmt_compress.c. */
-size_t ZSTD_compress_advanced_internal(ZSTD_CCtx* cctx,
-                                       void* dst, size_t dstCapacity,
-                                 const void* src, size_t srcSize,
-                                 const void* dict,size_t dictSize,
-                                 ZSTD_CCtx_params params);
-
 typedef struct {
     blockType_e blockType;
     U32 lastBlock;
     U32 origSize;
 } blockProperties_t;
 
 /*! ZSTD_getcBlockSize() :
-*   Provides the size of compressed block from block header `src` */
+ *  Provides the size of compressed block from block header `src` */
+/* Used by: decompress, fullbench (does not get its definition from here) */
 size_t ZSTD_getcBlockSize(const void* src, size_t srcSize,
                           blockProperties_t* bpPtr);
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif   /* ZSTD_CCOMMON_H_MODULE */
Index: head/sys/contrib/zstd/lib/compress/zstd_compress.h
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_compress.h	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_compress.h	(nonexistent)
@@ -1,307 +0,0 @@
-/*
- * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under both the BSD-style license (found in the
- * LICENSE file in the root directory of this source tree) and the GPLv2 (found
- * in the COPYING file in the root directory of this source tree).
- * You may select, at your option, one of the above-listed licenses.
- */
-
-
-#ifndef ZSTD_COMPRESS_H
-#define ZSTD_COMPRESS_H
-
-/*-*************************************
-*  Dependencies
-***************************************/
-#include "zstd_internal.h"
-#ifdef ZSTD_MULTITHREAD
-#  include "zstdmt_compress.h"
-#endif
-
-#if defined (__cplusplus)
-extern "C" {
-#endif
-
-/*-*************************************
-*  Constants
-***************************************/
-static const U32 g_searchStrength = 8;
-#define HASH_READ_SIZE 8
-
-
-/*-*************************************
-*  Context memory management
-***************************************/
-typedef enum { ZSTDcs_created=0, ZSTDcs_init, ZSTDcs_ongoing, ZSTDcs_ending } ZSTD_compressionStage_e;
-typedef enum { zcss_init=0, zcss_load, zcss_flush } ZSTD_cStreamStage;
-
-typedef struct ZSTD_prefixDict_s {
-    const void* dict;
-    size_t dictSize;
-    ZSTD_dictMode_e dictMode;
-} ZSTD_prefixDict;
-
-struct ZSTD_CCtx_s {
-    const BYTE* nextSrc;    /* next block here to continue on current prefix */
-    const BYTE* base;       /* All regular indexes relative to this position */
-    const BYTE* dictBase;   /* extDict indexes relative to this position */
-    U32   dictLimit;        /* below that point, need extDict */
-    U32   lowLimit;         /* below that point, no more data */
-    U32   nextToUpdate;     /* index from which to continue dictionary update */
-    U32   nextToUpdate3;    /* index from which to continue dictionary update */
-    U32   hashLog3;         /* dispatch table : larger == faster, more memory */
-    U32   loadedDictEnd;    /* index of end of dictionary */
-    ZSTD_compressionStage_e stage;
-    U32   dictID;
-    ZSTD_CCtx_params requestedParams;
-    ZSTD_CCtx_params appliedParams;
-    void* workSpace;
-    size_t workSpaceSize;
-    size_t blockSize;
-    U64 pledgedSrcSizePlusOne;  /* this way, 0 (default) == unknown */
-    U64 consumedSrcSize;
-    XXH64_state_t xxhState;
-    ZSTD_customMem customMem;
-    size_t staticSize;
-
-    seqStore_t seqStore;    /* sequences storage ptrs */
-    optState_t optState;
-    ldmState_t ldmState;    /* long distance matching state */
-    U32* hashTable;
-    U32* hashTable3;
-    U32* chainTable;
-    ZSTD_entropyCTables_t* entropy;
-
-    /* streaming */
-    char*  inBuff;
-    size_t inBuffSize;
-    size_t inToCompress;
-    size_t inBuffPos;
-    size_t inBuffTarget;
-    char*  outBuff;
-    size_t outBuffSize;
-    size_t outBuffContentSize;
-    size_t outBuffFlushedSize;
-    ZSTD_cStreamStage streamStage;
-    U32    frameEnded;
-
-    /* Dictionary */
-    ZSTD_CDict* cdictLocal;
-    const ZSTD_CDict* cdict;
-    ZSTD_prefixDict prefixDict;   /* single-usage dictionary */
-
-    /* Multi-threading */
-#ifdef ZSTD_MULTITHREAD
-    ZSTDMT_CCtx* mtctx;
-#endif
-};
-
-
-static const BYTE LL_Code[64] = {  0,  1,  2,  3,  4,  5,  6,  7,
-                                   8,  9, 10, 11, 12, 13, 14, 15,
-                                  16, 16, 17, 17, 18, 18, 19, 19,
-                                  20, 20, 20, 20, 21, 21, 21, 21,
-                                  22, 22, 22, 22, 22, 22, 22, 22,
-                                  23, 23, 23, 23, 23, 23, 23, 23,
-                                  24, 24, 24, 24, 24, 24, 24, 24,
-                                  24, 24, 24, 24, 24, 24, 24, 24 };
-
-static const BYTE ML_Code[128] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,
-                                  16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
-                                  32, 32, 33, 33, 34, 34, 35, 35, 36, 36, 36, 36, 37, 37, 37, 37,
-                                  38, 38, 38, 38, 38, 38, 38, 38, 39, 39, 39, 39, 39, 39, 39, 39,
-                                  40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,
-                                  41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41,
-                                  42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42,
-                                  42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42 };
-
-/*! ZSTD_storeSeq() :
-    Store a sequence (literal length, literals, offset code and match length code) into seqStore_t.
-    `offsetCode` : distance to match, or 0 == repCode.
-    `matchCode` : matchLength - MINMATCH
-*/
-MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const void* literals, U32 offsetCode, size_t matchCode)
-{
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG >= 6)
-    static const BYTE* g_start = NULL;
-    U32 const pos = (U32)((const BYTE*)literals - g_start);
-    if (g_start==NULL) g_start = (const BYTE*)literals;
-    if ((pos > 0) && (pos < 1000000000))
-        DEBUGLOG(6, "Cpos %6u :%5u literals & match %3u bytes at distance %6u",
-               pos, (U32)litLength, (U32)matchCode+MINMATCH, (U32)offsetCode);
-#endif
-    /* copy Literals */
-    assert(seqStorePtr->lit + litLength <= seqStorePtr->litStart + 128 KB);
-    ZSTD_wildcopy(seqStorePtr->lit, literals, litLength);
-    seqStorePtr->lit += litLength;
-
-    /* literal Length */
-    if (litLength>0xFFFF) {
-        seqStorePtr->longLengthID = 1;
-        seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
-    }
-    seqStorePtr->sequences[0].litLength = (U16)litLength;
-
-    /* match offset */
-    seqStorePtr->sequences[0].offset = offsetCode + 1;
-
-    /* match Length */
-    if (matchCode>0xFFFF) {
-        seqStorePtr->longLengthID = 2;
-        seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
-    }
-    seqStorePtr->sequences[0].matchLength = (U16)matchCode;
-
-    seqStorePtr->sequences++;
-}
-
-
-/*-*************************************
-*  Match length counter
-***************************************/
-static unsigned ZSTD_NbCommonBytes (register size_t val)
-{
-    if (MEM_isLittleEndian()) {
-        if (MEM_64bits()) {
-#       if defined(_MSC_VER) && defined(_WIN64)
-            unsigned long r = 0;
-            _BitScanForward64( &r, (U64)val );
-            return (unsigned)(r>>3);
-#       elif defined(__GNUC__) && (__GNUC__ >= 4)
-            return (__builtin_ctzll((U64)val) >> 3);
-#       else
-            static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2,
-                                                     0, 3, 1, 3, 1, 4, 2, 7,
-                                                     0, 2, 3, 6, 1, 5, 3, 5,
-                                                     1, 3, 4, 4, 2, 5, 6, 7,
-                                                     7, 0, 1, 2, 3, 3, 4, 6,
-                                                     2, 6, 5, 5, 3, 4, 5, 6,
-                                                     7, 1, 2, 4, 6, 4, 4, 5,
-                                                     7, 2, 6, 5, 7, 6, 7, 7 };
-            return DeBruijnBytePos[((U64)((val & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58];
-#       endif
-        } else { /* 32 bits */
-#       if defined(_MSC_VER)
-            unsigned long r=0;
-            _BitScanForward( &r, (U32)val );
-            return (unsigned)(r>>3);
-#       elif defined(__GNUC__) && (__GNUC__ >= 3)
-            return (__builtin_ctz((U32)val) >> 3);
-#       else
-            static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0,
-                                                     3, 2, 2, 1, 3, 2, 0, 1,
-                                                     3, 3, 1, 2, 2, 2, 2, 0,
-                                                     3, 1, 2, 0, 1, 0, 1, 1 };
-            return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
-#       endif
-        }
-    } else {  /* Big Endian CPU */
-        if (MEM_64bits()) {
-#       if defined(_MSC_VER) && defined(_WIN64)
-            unsigned long r = 0;
-            _BitScanReverse64( &r, val );
-            return (unsigned)(r>>3);
-#       elif defined(__GNUC__) && (__GNUC__ >= 4) && __has_builtin(__builtin_clzll)
-            return (__builtin_clzll(val) >> 3);
-#       else
-            unsigned r;
-            const unsigned n32 = sizeof(size_t)*4;   /* calculate this way due to compiler complaining in 32-bits mode */
-            if (!(val>>n32)) { r=4; } else { r=0; val>>=n32; }
-            if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
-            r += (!val);
-            return r;
-#       endif
-        } else { /* 32 bits */
-#       if defined(_MSC_VER)
-            unsigned long r = 0;
-            _BitScanReverse( &r, (unsigned long)val );
-            return (unsigned)(r>>3);
-#       elif defined(__GNUC__) && (__GNUC__ >= 3) && __has_builtin(__builtin_clz)
-            return (__builtin_clz((U32)val) >> 3);
-#       else
-            unsigned r;
-            if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
-            r += (!val);
-            return r;
-#       endif
-    }   }
-}
-
-
-MEM_STATIC size_t ZSTD_count(const BYTE* pIn, const BYTE* pMatch, const BYTE* const pInLimit)
-{
-    const BYTE* const pStart = pIn;
-    const BYTE* const pInLoopLimit = pInLimit - (sizeof(size_t)-1);
-
-    while (pIn < pInLoopLimit) {
-        size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn);
-        if (!diff) { pIn+=sizeof(size_t); pMatch+=sizeof(size_t); continue; }
-        pIn += ZSTD_NbCommonBytes(diff);
-        return (size_t)(pIn - pStart);
-    }
-    if (MEM_64bits()) if ((pIn<(pInLimit-3)) && (MEM_read32(pMatch) == MEM_read32(pIn))) { pIn+=4; pMatch+=4; }
-    if ((pIn<(pInLimit-1)) && (MEM_read16(pMatch) == MEM_read16(pIn))) { pIn+=2; pMatch+=2; }
-    if ((pIn> (32-h) ; }
-MEM_STATIC size_t ZSTD_hash3Ptr(const void* ptr, U32 h) { return ZSTD_hash3(MEM_readLE32(ptr), h); } /* only in zstd_opt.h */
-
-static const U32 prime4bytes = 2654435761U;
-static U32    ZSTD_hash4(U32 u, U32 h) { return (u * prime4bytes) >> (32-h) ; }
-static size_t ZSTD_hash4Ptr(const void* ptr, U32 h) { return ZSTD_hash4(MEM_read32(ptr), h); }
-
-static const U64 prime5bytes = 889523592379ULL;
-static size_t ZSTD_hash5(U64 u, U32 h) { return (size_t)(((u  << (64-40)) * prime5bytes) >> (64-h)) ; }
-static size_t ZSTD_hash5Ptr(const void* p, U32 h) { return ZSTD_hash5(MEM_readLE64(p), h); }
-
-static const U64 prime6bytes = 227718039650203ULL;
-static size_t ZSTD_hash6(U64 u, U32 h) { return (size_t)(((u  << (64-48)) * prime6bytes) >> (64-h)) ; }
-static size_t ZSTD_hash6Ptr(const void* p, U32 h) { return ZSTD_hash6(MEM_readLE64(p), h); }
-
-static const U64 prime7bytes = 58295818150454627ULL;
-static size_t ZSTD_hash7(U64 u, U32 h) { return (size_t)(((u  << (64-56)) * prime7bytes) >> (64-h)) ; }
-static size_t ZSTD_hash7Ptr(const void* p, U32 h) { return ZSTD_hash7(MEM_readLE64(p), h); }
-
-static const U64 prime8bytes = 0xCF1BBCDCB7A56463ULL;
-static size_t ZSTD_hash8(U64 u, U32 h) { return (size_t)(((u) * prime8bytes) >> (64-h)) ; }
-static size_t ZSTD_hash8Ptr(const void* p, U32 h) { return ZSTD_hash8(MEM_readLE64(p), h); }
-
-MEM_STATIC size_t ZSTD_hashPtr(const void* p, U32 hBits, U32 mls)
-{
-    switch(mls)
-    {
-    default:
-    case 4: return ZSTD_hash4Ptr(p, hBits);
-    case 5: return ZSTD_hash5Ptr(p, hBits);
-    case 6: return ZSTD_hash6Ptr(p, hBits);
-    case 7: return ZSTD_hash7Ptr(p, hBits);
-    case 8: return ZSTD_hash8Ptr(p, hBits);
-    }
-}
-
-#if defined (__cplusplus)
-}
-#endif
-
-#endif /* ZSTD_COMPRESS_H */

Property changes on: head/sys/contrib/zstd/lib/compress/zstd_compress.h
___________________________________________________________________
Deleted: svn:eol-style
## -1 +0,0 ##
-native
\ No newline at end of property
Deleted: svn:keywords
## -1 +0,0 ##
-FreeBSD=%H
\ No newline at end of property
Deleted: svn:mime-type
## -1 +0,0 ##
-text/plain
\ No newline at end of property
Index: head/sys/contrib/zstd/lib/compress/zstd_compress.c
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_compress.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_compress.c	(revision 330894)
@@ -1,3023 +1,3120 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 
 /*-*************************************
 *  Tuning parameters
 ***************************************/
 #ifndef ZSTD_CLEVEL_DEFAULT
 #  define ZSTD_CLEVEL_DEFAULT 3
 #endif
 
 
 /*-*************************************
 *  Dependencies
 ***************************************/
 #include          /* memset */
 #include "mem.h"
 #define FSE_STATIC_LINKING_ONLY   /* FSE_encodeSymbol */
 #include "fse.h"
 #define HUF_STATIC_LINKING_ONLY
 #include "huf.h"
-#include "zstd_compress.h"
+#include "zstd_compress_internal.h"
 #include "zstd_fast.h"
 #include "zstd_double_fast.h"
 #include "zstd_lazy.h"
 #include "zstd_opt.h"
 #include "zstd_ldm.h"
 
 
 /*-*************************************
 *  Helper functions
 ***************************************/
 size_t ZSTD_compressBound(size_t srcSize) {
     return ZSTD_COMPRESSBOUND(srcSize);
 }
 
 
 /*-*************************************
-*  Sequence storage
-***************************************/
-static void ZSTD_resetSeqStore(seqStore_t* ssPtr)
-{
-    ssPtr->lit = ssPtr->litStart;
-    ssPtr->sequences = ssPtr->sequencesStart;
-    ssPtr->longLengthID = 0;
-}
-
-
-/*-*************************************
 *  Context memory management
 ***************************************/
 struct ZSTD_CDict_s {
     void* dictBuffer;
     const void* dictContent;
     size_t dictContentSize;
     ZSTD_CCtx* refContext;
 };  /* typedef'd to ZSTD_CDict within "zstd.h" */
 
 ZSTD_CCtx* ZSTD_createCCtx(void)
 {
     return ZSTD_createCCtx_advanced(ZSTD_defaultCMem);
 }
 
 ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem)
 {
     ZSTD_CCtx* cctx;
 
     if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
 
     cctx = (ZSTD_CCtx*) ZSTD_calloc(sizeof(ZSTD_CCtx), customMem);
     if (!cctx) return NULL;
     cctx->customMem = customMem;
     cctx->requestedParams.compressionLevel = ZSTD_CLEVEL_DEFAULT;
+    cctx->requestedParams.fParams.contentSizeFlag = 1;
     ZSTD_STATIC_ASSERT(zcss_init==0);
     ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_UNKNOWN==(0ULL - 1));
     return cctx;
 }
 
 ZSTD_CCtx* ZSTD_initStaticCCtx(void *workspace, size_t workspaceSize)
 {
     ZSTD_CCtx* const cctx = (ZSTD_CCtx*) workspace;
     if (workspaceSize <= sizeof(ZSTD_CCtx)) return NULL;  /* minimum size */
     if ((size_t)workspace & 7) return NULL;  /* must be 8-aligned */
     memset(workspace, 0, workspaceSize);   /* may be a bit generous, could memset be smaller ? */
     cctx->staticSize = workspaceSize;
     cctx->workSpace = (void*)(cctx+1);
     cctx->workSpaceSize = workspaceSize - sizeof(ZSTD_CCtx);
 
     /* entropy space (never moves) */
     if (cctx->workSpaceSize < sizeof(ZSTD_entropyCTables_t)) return NULL;
     assert(((size_t)cctx->workSpace & (sizeof(void*)-1)) == 0);   /* ensure correct alignment */
     cctx->entropy = (ZSTD_entropyCTables_t*)cctx->workSpace;
 
     return cctx;
 }
 
 size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx)
 {
     if (cctx==NULL) return 0;   /* support free on NULL */
     if (cctx->staticSize) return ERROR(memory_allocation);   /* not compatible with static CCtx */
     ZSTD_free(cctx->workSpace, cctx->customMem);
     cctx->workSpace = NULL;
     ZSTD_freeCDict(cctx->cdictLocal);
     cctx->cdictLocal = NULL;
 #ifdef ZSTD_MULTITHREAD
     ZSTDMT_freeCCtx(cctx->mtctx);
     cctx->mtctx = NULL;
 #endif
     ZSTD_free(cctx, cctx->customMem);
     return 0;   /* reserved as a potential error code in the future */
 }
 
 
 static size_t ZSTD_sizeof_mtctx(const ZSTD_CCtx* cctx)
 {
 #ifdef ZSTD_MULTITHREAD
     return ZSTDMT_sizeof_CCtx(cctx->mtctx);
 #else
     (void) cctx;
     return 0;
 #endif
 }
 
 
 size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx)
 {
     if (cctx==NULL) return 0;   /* support sizeof on NULL */
     DEBUGLOG(3, "sizeof(*cctx) : %u", (U32)sizeof(*cctx));
     DEBUGLOG(3, "workSpaceSize (including streaming buffers): %u", (U32)cctx->workSpaceSize);
     DEBUGLOG(3, "inner cdict : %u", (U32)ZSTD_sizeof_CDict(cctx->cdictLocal));
     DEBUGLOG(3, "inner MTCTX : %u", (U32)ZSTD_sizeof_mtctx(cctx));
     return sizeof(*cctx) + cctx->workSpaceSize
            + ZSTD_sizeof_CDict(cctx->cdictLocal)
            + ZSTD_sizeof_mtctx(cctx);
 }
 
 size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs)
 {
     return ZSTD_sizeof_CCtx(zcs);  /* same object */
 }
 
 /* private API call, for dictBuilder only */
 const seqStore_t* ZSTD_getSeqStore(const ZSTD_CCtx* ctx) { return &(ctx->seqStore); }
 
 #define ZSTD_CLEVEL_CUSTOM 999
 
 static ZSTD_compressionParameters ZSTD_getCParamsFromCCtxParams(
-        ZSTD_CCtx_params params, U64 srcSizeHint, size_t dictSize)
+        ZSTD_CCtx_params CCtxParams, U64 srcSizeHint, size_t dictSize)
 {
-    return (params.compressionLevel == ZSTD_CLEVEL_CUSTOM ?
-                    params.cParams :
-                    ZSTD_getCParams(params.compressionLevel, srcSizeHint, dictSize));
+    DEBUGLOG(4, "ZSTD_getCParamsFromCCtxParams: srcSize = %u, dictSize = %u",
+                (U32)srcSizeHint, (U32)dictSize);
+    return (CCtxParams.compressionLevel == ZSTD_CLEVEL_CUSTOM) ?
+                CCtxParams.cParams :
+                ZSTD_getCParams(CCtxParams.compressionLevel, srcSizeHint, dictSize);
 }
 
-static void ZSTD_cLevelToCCtxParams_srcSize(ZSTD_CCtx_params* params, U64 srcSize)
+static void ZSTD_cLevelToCCtxParams_srcSize(ZSTD_CCtx_params* CCtxParams, U64 srcSize)
 {
-    params->cParams = ZSTD_getCParamsFromCCtxParams(*params, srcSize, 0);
-    params->compressionLevel = ZSTD_CLEVEL_CUSTOM;
+    DEBUGLOG(4, "ZSTD_cLevelToCCtxParams_srcSize: srcSize = %u",
+                (U32)srcSize);
+    CCtxParams->cParams = ZSTD_getCParamsFromCCtxParams(*CCtxParams, srcSize, 0);
+    CCtxParams->compressionLevel = ZSTD_CLEVEL_CUSTOM;
 }
 
 static void ZSTD_cLevelToCParams(ZSTD_CCtx* cctx)
 {
+    DEBUGLOG(4, "ZSTD_cLevelToCParams: level=%i", cctx->requestedParams.compressionLevel);
     ZSTD_cLevelToCCtxParams_srcSize(
             &cctx->requestedParams, cctx->pledgedSrcSizePlusOne-1);
 }
 
-static void ZSTD_cLevelToCCtxParams(ZSTD_CCtx_params* params)
+static void ZSTD_cLevelToCCtxParams(ZSTD_CCtx_params* CCtxParams)
 {
-    ZSTD_cLevelToCCtxParams_srcSize(params, 0);
+    DEBUGLOG(4, "ZSTD_cLevelToCCtxParams");
+    ZSTD_cLevelToCCtxParams_srcSize(CCtxParams, ZSTD_CONTENTSIZE_UNKNOWN);
 }
 
 static ZSTD_CCtx_params ZSTD_makeCCtxParamsFromCParams(
         ZSTD_compressionParameters cParams)
 {
     ZSTD_CCtx_params cctxParams;
     memset(&cctxParams, 0, sizeof(cctxParams));
     cctxParams.cParams = cParams;
     cctxParams.compressionLevel = ZSTD_CLEVEL_CUSTOM;
     return cctxParams;
 }
 
 static ZSTD_CCtx_params* ZSTD_createCCtxParams_advanced(
         ZSTD_customMem customMem)
 {
     ZSTD_CCtx_params* params;
     if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
     params = (ZSTD_CCtx_params*)ZSTD_calloc(
             sizeof(ZSTD_CCtx_params), customMem);
     if (!params) { return NULL; }
     params->customMem = customMem;
     params->compressionLevel = ZSTD_CLEVEL_DEFAULT;
     return params;
 }
 
 ZSTD_CCtx_params* ZSTD_createCCtxParams(void)
 {
     return ZSTD_createCCtxParams_advanced(ZSTD_defaultCMem);
 }
 
 size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params)
 {
     if (params == NULL) { return 0; }
     ZSTD_free(params, params->customMem);
     return 0;
 }
 
 size_t ZSTD_resetCCtxParams(ZSTD_CCtx_params* params)
 {
     return ZSTD_initCCtxParams(params, ZSTD_CLEVEL_DEFAULT);
 }
 
 size_t ZSTD_initCCtxParams(ZSTD_CCtx_params* cctxParams, int compressionLevel) {
     if (!cctxParams) { return ERROR(GENERIC); }
     memset(cctxParams, 0, sizeof(*cctxParams));
     cctxParams->compressionLevel = compressionLevel;
     return 0;
 }
 
 size_t ZSTD_initCCtxParams_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params)
 {
     if (!cctxParams) { return ERROR(GENERIC); }
     CHECK_F( ZSTD_checkCParams(params.cParams) );
     memset(cctxParams, 0, sizeof(*cctxParams));
     cctxParams->cParams = params.cParams;
     cctxParams->fParams = params.fParams;
     cctxParams->compressionLevel = ZSTD_CLEVEL_CUSTOM;
     return 0;
 }
 
 static ZSTD_CCtx_params ZSTD_assignParamsToCCtxParams(
         ZSTD_CCtx_params cctxParams, ZSTD_parameters params)
 {
     ZSTD_CCtx_params ret = cctxParams;
     ret.cParams = params.cParams;
     ret.fParams = params.fParams;
     ret.compressionLevel = ZSTD_CLEVEL_CUSTOM;
     return ret;
 }
 
 #define CLAMPCHECK(val,min,max) {            \
     if (((val)<(min)) | ((val)>(max))) {     \
         return ERROR(parameter_outOfBound);  \
 }   }
 
 size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, unsigned value)
 {
+    DEBUGLOG(4, "ZSTD_CCtx_setParameter (%u, %u)", (U32)param, value);
     if (cctx->streamStage != zcss_init) return ERROR(stage_wrong);
 
     switch(param)
     {
     case ZSTD_p_format :
         return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
 
     case ZSTD_p_compressionLevel:
-        if (value == 0) return 0;  /* special value : 0 means "don't change anything" */
         if (cctx->cdict) return ERROR(stage_wrong);
         return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
 
     case ZSTD_p_windowLog:
     case ZSTD_p_hashLog:
     case ZSTD_p_chainLog:
     case ZSTD_p_searchLog:
     case ZSTD_p_minMatch:
     case ZSTD_p_targetLength:
     case ZSTD_p_compressionStrategy:
-        if (value == 0) return 0;  /* special value : 0 means "don't change anything" */
         if (cctx->cdict) return ERROR(stage_wrong);
-        ZSTD_cLevelToCParams(cctx);  /* Can optimize if srcSize is known */
+        if (value>0) ZSTD_cLevelToCParams(cctx);  /* Can optimize if srcSize is known */
         return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
 
     case ZSTD_p_contentSizeFlag:
     case ZSTD_p_checksumFlag:
     case ZSTD_p_dictIDFlag:
         return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
 
     case ZSTD_p_forceMaxWindow :  /* Force back-references to remain < windowSize,
-                                   * even when referencing into Dictionary content
+                                   * even when referencing into Dictionary content.
                                    * default : 0 when using a CDict, 1 when using a Prefix */
-        cctx->loadedDictEnd = 0;
         return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
 
     case ZSTD_p_nbThreads:
-        if (value==0) return 0;
-        DEBUGLOG(5, " setting nbThreads : %u", value);
-        if (value > 1 && cctx->staticSize) {
+        if ((value > 1) && cctx->staticSize) {
             return ERROR(parameter_unsupported);  /* MT not compatible with static alloc */
         }
         return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
 
     case ZSTD_p_jobSize:
         return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
 
     case ZSTD_p_overlapSizeLog:
-        DEBUGLOG(5, " setting overlap with nbThreads == %u", cctx->requestedParams.nbThreads);
         return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
 
     case ZSTD_p_enableLongDistanceMatching:
         if (cctx->cdict) return ERROR(stage_wrong);
-        if (value != 0) {
-            ZSTD_cLevelToCParams(cctx);
-        }
+        if (value>0) ZSTD_cLevelToCParams(cctx);
         return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
 
     case ZSTD_p_ldmHashLog:
     case ZSTD_p_ldmMinMatch:
-        if (value == 0) return 0;  /* special value : 0 means "don't change anything" */
-        if (cctx->cdict) return ERROR(stage_wrong);
-        return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
-
     case ZSTD_p_ldmBucketSizeLog:
     case ZSTD_p_ldmHashEveryLog:
         if (cctx->cdict) return ERROR(stage_wrong);
         return ZSTD_CCtxParam_setParameter(&cctx->requestedParams, param, value);
 
     default: return ERROR(parameter_unsupported);
     }
 }
 
 size_t ZSTD_CCtxParam_setParameter(
-        ZSTD_CCtx_params* params, ZSTD_cParameter param, unsigned value)
+        ZSTD_CCtx_params* CCtxParams, ZSTD_cParameter param, unsigned value)
 {
+    DEBUGLOG(4, "ZSTD_CCtxParam_setParameter (%u, %u)", (U32)param, value);
     switch(param)
     {
     case ZSTD_p_format :
         if (value > (unsigned)ZSTD_f_zstd1_magicless)
             return ERROR(parameter_unsupported);
-        params->format = (ZSTD_format_e)value;
-        return 0;
+        CCtxParams->format = (ZSTD_format_e)value;
+        return (size_t)CCtxParams->format;
 
     case ZSTD_p_compressionLevel :
         if ((int)value > ZSTD_maxCLevel()) value = ZSTD_maxCLevel();
-        if (value == 0) return 0;
-        params->compressionLevel = value;
-        return 0;
+        if (value)  /* 0 : does not change current level */
+            CCtxParams->compressionLevel = value;
+        return CCtxParams->compressionLevel;
 
     case ZSTD_p_windowLog :
-        if (value == 0) return 0;
-        CLAMPCHECK(value, ZSTD_WINDOWLOG_MIN, ZSTD_WINDOWLOG_MAX);
-        ZSTD_cLevelToCCtxParams(params);
-        params->cParams.windowLog = value;
-        return 0;
+        DEBUGLOG(4, "ZSTD_CCtxParam_setParameter: set windowLog=%u", value);
+        if (value) {  /* 0 : does not change current windowLog */
+            CLAMPCHECK(value, ZSTD_WINDOWLOG_MIN, ZSTD_WINDOWLOG_MAX);
+            ZSTD_cLevelToCCtxParams(CCtxParams);
+            CCtxParams->cParams.windowLog = value;
+        }
+        return CCtxParams->cParams.windowLog;
 
     case ZSTD_p_hashLog :
-        if (value == 0) return 0;
-        CLAMPCHECK(value, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
-        ZSTD_cLevelToCCtxParams(params);
-        params->cParams.hashLog = value;
-        return 0;
+        if (value) { /* 0 : does not change current hashLog */
+            CLAMPCHECK(value, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
+            ZSTD_cLevelToCCtxParams(CCtxParams);
+            CCtxParams->cParams.hashLog = value;
+        }
+        return CCtxParams->cParams.hashLog;
 
     case ZSTD_p_chainLog :
-        if (value == 0) return 0;
-        CLAMPCHECK(value, ZSTD_CHAINLOG_MIN, ZSTD_CHAINLOG_MAX);
-        ZSTD_cLevelToCCtxParams(params);
-        params->cParams.chainLog = value;
-        return 0;
+        if (value) { /* 0 : does not change current chainLog */
+            CLAMPCHECK(value, ZSTD_CHAINLOG_MIN, ZSTD_CHAINLOG_MAX);
+            ZSTD_cLevelToCCtxParams(CCtxParams);
+            CCtxParams->cParams.chainLog = value;
+        }
+        return CCtxParams->cParams.chainLog;
 
     case ZSTD_p_searchLog :
-        if (value == 0) return 0;
-        CLAMPCHECK(value, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
-        ZSTD_cLevelToCCtxParams(params);
-        params->cParams.searchLog = value;
-        return 0;
+        if (value) { /* 0 : does not change current searchLog */
+            CLAMPCHECK(value, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
+            ZSTD_cLevelToCCtxParams(CCtxParams);
+            CCtxParams->cParams.searchLog = value;
+        }
+        return value;
 
     case ZSTD_p_minMatch :
-        if (value == 0) return 0;
-        CLAMPCHECK(value, ZSTD_SEARCHLENGTH_MIN, ZSTD_SEARCHLENGTH_MAX);
-        ZSTD_cLevelToCCtxParams(params);
-        params->cParams.searchLength = value;
-        return 0;
+        if (value) { /* 0 : does not change current minMatch length */
+            CLAMPCHECK(value, ZSTD_SEARCHLENGTH_MIN, ZSTD_SEARCHLENGTH_MAX);
+            ZSTD_cLevelToCCtxParams(CCtxParams);
+            CCtxParams->cParams.searchLength = value;
+        }
+        return CCtxParams->cParams.searchLength;
 
     case ZSTD_p_targetLength :
-        if (value == 0) return 0;
-        CLAMPCHECK(value, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
-        ZSTD_cLevelToCCtxParams(params);
-        params->cParams.targetLength = value;
-        return 0;
+        if (value) { /* 0 : does not change current sufficient_len */
+            CLAMPCHECK(value, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
+            ZSTD_cLevelToCCtxParams(CCtxParams);
+            CCtxParams->cParams.targetLength = value;
+        }
+        return CCtxParams->cParams.targetLength;
 
     case ZSTD_p_compressionStrategy :
-        if (value == 0) return 0;
-        CLAMPCHECK(value, (unsigned)ZSTD_fast, (unsigned)ZSTD_btultra);
-        ZSTD_cLevelToCCtxParams(params);
-        params->cParams.strategy = (ZSTD_strategy)value;
-        return 0;
+        if (value) { /* 0 : does not change currentstrategy */
+            CLAMPCHECK(value, (unsigned)ZSTD_fast, (unsigned)ZSTD_btultra);
+            ZSTD_cLevelToCCtxParams(CCtxParams);
+            CCtxParams->cParams.strategy = (ZSTD_strategy)value;
+        }
+        return (size_t)CCtxParams->cParams.strategy;
 
     case ZSTD_p_contentSizeFlag :
         /* Content size written in frame header _when known_ (default:1) */
-        DEBUGLOG(5, "set content size flag = %u", (value>0));
-        params->fParams.contentSizeFlag = value > 0;
-        return 0;
+        DEBUGLOG(4, "set content size flag = %u", (value>0));
+        CCtxParams->fParams.contentSizeFlag = value > 0;
+        return CCtxParams->fParams.contentSizeFlag;
 
     case ZSTD_p_checksumFlag :
         /* A 32-bits content checksum will be calculated and written at end of frame (default:0) */
-        params->fParams.checksumFlag = value > 0;
-        return 0;
+        CCtxParams->fParams.checksumFlag = value > 0;
+        return CCtxParams->fParams.checksumFlag;
 
     case ZSTD_p_dictIDFlag : /* When applicable, dictionary's dictID is provided in frame header (default:1) */
-        DEBUGLOG(5, "set dictIDFlag = %u", (value>0));
-        params->fParams.noDictIDFlag = (value == 0);
-        return 0;
+        DEBUGLOG(4, "set dictIDFlag = %u", (value>0));
+        CCtxParams->fParams.noDictIDFlag = (value == 0);
+        return !CCtxParams->fParams.noDictIDFlag;
 
     case ZSTD_p_forceMaxWindow :
-        params->forceWindow = value > 0;
-        return 0;
+        CCtxParams->forceWindow = (value > 0);
+        return CCtxParams->forceWindow;
 
     case ZSTD_p_nbThreads :
-        if (value == 0) return 0;
+        if (value == 0) return CCtxParams->nbThreads;
 #ifndef ZSTD_MULTITHREAD
         if (value > 1) return ERROR(parameter_unsupported);
-        return 0;
+        return 1;
 #else
-        return ZSTDMT_initializeCCtxParameters(params, value);
+        return ZSTDMT_CCtxParam_setNbThreads(CCtxParams, value);
 #endif
 
     case ZSTD_p_jobSize :
 #ifndef ZSTD_MULTITHREAD
         return ERROR(parameter_unsupported);
 #else
-        if (params->nbThreads <= 1) return ERROR(parameter_unsupported);
-        return ZSTDMT_CCtxParam_setMTCtxParameter(params, ZSTDMT_p_sectionSize, value);
+        if (CCtxParams->nbThreads <= 1) return ERROR(parameter_unsupported);
+        return ZSTDMT_CCtxParam_setMTCtxParameter(CCtxParams, ZSTDMT_p_jobSize, value);
 #endif
 
     case ZSTD_p_overlapSizeLog :
 #ifndef ZSTD_MULTITHREAD
         return ERROR(parameter_unsupported);
 #else
-        if (params->nbThreads <= 1) return ERROR(parameter_unsupported);
-        return ZSTDMT_CCtxParam_setMTCtxParameter(params, ZSTDMT_p_overlapSectionLog, value);
+        if (CCtxParams->nbThreads <= 1) return ERROR(parameter_unsupported);
+        return ZSTDMT_CCtxParam_setMTCtxParameter(CCtxParams, ZSTDMT_p_overlapSectionLog, value);
 #endif
 
     case ZSTD_p_enableLongDistanceMatching :
-        if (value != 0) {
-            ZSTD_cLevelToCCtxParams(params);
-            params->cParams.windowLog = ZSTD_LDM_DEFAULT_WINDOW_LOG;
+        if (value) {
+            ZSTD_cLevelToCCtxParams(CCtxParams);
+            CCtxParams->cParams.windowLog = ZSTD_LDM_DEFAULT_WINDOW_LOG;
         }
-        return ZSTD_ldm_initializeParameters(¶ms->ldmParams, value);
+        return ZSTD_ldm_initializeParameters(&CCtxParams->ldmParams, value);
 
     case ZSTD_p_ldmHashLog :
-        if (value == 0) return 0;
-        CLAMPCHECK(value, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
-        params->ldmParams.hashLog = value;
-        return 0;
+        if (value) { /* 0 : does not change current ldmHashLog */
+            CLAMPCHECK(value, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
+            CCtxParams->ldmParams.hashLog = value;
+        }
+        return CCtxParams->ldmParams.hashLog;
 
     case ZSTD_p_ldmMinMatch :
-        if (value == 0) return 0;
-        CLAMPCHECK(value, ZSTD_LDM_MINMATCH_MIN, ZSTD_LDM_MINMATCH_MAX);
-        params->ldmParams.minMatchLength = value;
-        return 0;
+        if (value) { /* 0 : does not change current ldmMinMatch */
+            CLAMPCHECK(value, ZSTD_LDM_MINMATCH_MIN, ZSTD_LDM_MINMATCH_MAX);
+            CCtxParams->ldmParams.minMatchLength = value;
+        }
+        return CCtxParams->ldmParams.minMatchLength;
 
     case ZSTD_p_ldmBucketSizeLog :
         if (value > ZSTD_LDM_BUCKETSIZELOG_MAX) {
             return ERROR(parameter_outOfBound);
         }
-        params->ldmParams.bucketSizeLog = value;
-        return 0;
+        CCtxParams->ldmParams.bucketSizeLog = value;
+        return value;
 
     case ZSTD_p_ldmHashEveryLog :
         if (value > ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN) {
             return ERROR(parameter_outOfBound);
         }
-        params->ldmParams.hashEveryLog = value;
-        return 0;
+        CCtxParams->ldmParams.hashEveryLog = value;
+        return value;
 
     default: return ERROR(parameter_unsupported);
     }
 }
 
-/**
- * This function should be updated whenever ZSTD_CCtx_params is updated.
- * Parameters are copied manually before the dictionary is loaded.
- * The multithreading parameters jobSize and overlapSizeLog are set only if
- * nbThreads > 1.
- *
- * Pledged srcSize is treated as unknown.
+/** ZSTD_CCtx_setParametersUsingCCtxParams() :
+ *  just applies `params` into `cctx`
+ *  no action is performed, parameters are merely stored.
  */
 size_t ZSTD_CCtx_setParametersUsingCCtxParams(
         ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params)
 {
     if (cctx->streamStage != zcss_init) return ERROR(stage_wrong);
     if (cctx->cdict) return ERROR(stage_wrong);
 
-    /* Assume the compression and frame parameters are validated */
-    cctx->requestedParams.cParams = params->cParams;
-    cctx->requestedParams.fParams = params->fParams;
-    cctx->requestedParams.compressionLevel = params->compressionLevel;
+    cctx->requestedParams = *params;
 
-    /* Set force window explicitly since it sets cctx->loadedDictEnd */
-    CHECK_F( ZSTD_CCtx_setParameter(
-                   cctx, ZSTD_p_forceMaxWindow, params->forceWindow) );
-
-    /* Set multithreading parameters explicitly */
-    CHECK_F( ZSTD_CCtx_setParameter(cctx, ZSTD_p_nbThreads, params->nbThreads) );
-    if (params->nbThreads > 1) {
-        CHECK_F( ZSTD_CCtx_setParameter(cctx, ZSTD_p_jobSize, params->jobSize) );
-        CHECK_F( ZSTD_CCtx_setParameter(
-                    cctx, ZSTD_p_overlapSizeLog, params->overlapSizeLog) );
-    }
-
-    /* Copy long distance matching parameters */
-    cctx->requestedParams.ldmParams = params->ldmParams;
-
-    /* customMem is used only for create/free params and can be ignored */
     return 0;
 }
 
 ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize)
 {
-    DEBUGLOG(4, " setting pledgedSrcSize to %u", (U32)pledgedSrcSize);
+    DEBUGLOG(4, "ZSTD_CCtx_setPledgedSrcSize to %u bytes", (U32)pledgedSrcSize);
     if (cctx->streamStage != zcss_init) return ERROR(stage_wrong);
     cctx->pledgedSrcSizePlusOne = pledgedSrcSize+1;
     return 0;
 }
 
 size_t ZSTD_CCtx_loadDictionary_advanced(
         ZSTD_CCtx* cctx, const void* dict, size_t dictSize,
         ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictMode_e dictMode)
 {
     if (cctx->streamStage != zcss_init) return ERROR(stage_wrong);
     if (cctx->staticSize) return ERROR(memory_allocation);  /* no malloc for static CCtx */
-    DEBUGLOG(4, "load dictionary of size %u", (U32)dictSize);
+    DEBUGLOG(4, "ZSTD_CCtx_loadDictionary_advanced (size: %u)", (U32)dictSize);
     ZSTD_freeCDict(cctx->cdictLocal);  /* in case one already exists */
     if (dict==NULL || dictSize==0) {   /* no dictionary mode */
         cctx->cdictLocal = NULL;
         cctx->cdict = NULL;
     } else {
         ZSTD_compressionParameters const cParams =
-                ZSTD_getCParamsFromCCtxParams(cctx->requestedParams, 0, dictSize);
+                ZSTD_getCParamsFromCCtxParams(cctx->requestedParams, cctx->pledgedSrcSizePlusOne-1, dictSize);
         cctx->cdictLocal = ZSTD_createCDict_advanced(
                                 dict, dictSize,
                                 dictLoadMethod, dictMode,
                                 cParams, cctx->customMem);
         cctx->cdict = cctx->cdictLocal;
         if (cctx->cdictLocal == NULL)
             return ERROR(memory_allocation);
     }
     return 0;
 }
 
 ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_byReference(
       ZSTD_CCtx* cctx, const void* dict, size_t dictSize)
 {
     return ZSTD_CCtx_loadDictionary_advanced(
             cctx, dict, dictSize, ZSTD_dlm_byRef, ZSTD_dm_auto);
 }
 
 ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize)
 {
     return ZSTD_CCtx_loadDictionary_advanced(
             cctx, dict, dictSize, ZSTD_dlm_byCopy, ZSTD_dm_auto);
 }
 
 
 size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict)
 {
     if (cctx->streamStage != zcss_init) return ERROR(stage_wrong);
     cctx->cdict = cdict;
     memset(&cctx->prefixDict, 0, sizeof(cctx->prefixDict));  /* exclusive */
     return 0;
 }
 
 size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize)
 {
     return ZSTD_CCtx_refPrefix_advanced(cctx, prefix, prefixSize, ZSTD_dm_rawContent);
 }
 
 size_t ZSTD_CCtx_refPrefix_advanced(
         ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictMode_e dictMode)
 {
     if (cctx->streamStage != zcss_init) return ERROR(stage_wrong);
     cctx->cdict = NULL;   /* prefix discards any prior cdict */
     cctx->prefixDict.dict = prefix;
     cctx->prefixDict.dictSize = prefixSize;
     cctx->prefixDict.dictMode = dictMode;
     return 0;
 }
 
 static void ZSTD_startNewCompression(ZSTD_CCtx* cctx)
 {
     cctx->streamStage = zcss_init;
     cctx->pledgedSrcSizePlusOne = 0;
 }
 
 /*! ZSTD_CCtx_reset() :
  *  Also dumps dictionary */
 void ZSTD_CCtx_reset(ZSTD_CCtx* cctx)
 {
     ZSTD_startNewCompression(cctx);
     cctx->cdict = NULL;
 }
 
 /** ZSTD_checkCParams() :
     control CParam values remain within authorized range.
     @return : 0, or an error code if one value is beyond authorized range */
 size_t ZSTD_checkCParams(ZSTD_compressionParameters cParams)
 {
     CLAMPCHECK(cParams.windowLog, ZSTD_WINDOWLOG_MIN, ZSTD_WINDOWLOG_MAX);
     CLAMPCHECK(cParams.chainLog, ZSTD_CHAINLOG_MIN, ZSTD_CHAINLOG_MAX);
     CLAMPCHECK(cParams.hashLog, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
     CLAMPCHECK(cParams.searchLog, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
     CLAMPCHECK(cParams.searchLength, ZSTD_SEARCHLENGTH_MIN, ZSTD_SEARCHLENGTH_MAX);
     CLAMPCHECK(cParams.targetLength, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
     if ((U32)(cParams.strategy) > (U32)ZSTD_btultra)
         return ERROR(parameter_unsupported);
     return 0;
 }
 
 /** ZSTD_clampCParams() :
  *  make CParam values within valid range.
  *  @return : valid CParams */
 static ZSTD_compressionParameters ZSTD_clampCParams(ZSTD_compressionParameters cParams)
 {
 #   define CLAMP(val,min,max) {      \
         if (valmax) val=max;   \
     }
     CLAMP(cParams.windowLog, ZSTD_WINDOWLOG_MIN, ZSTD_WINDOWLOG_MAX);
     CLAMP(cParams.chainLog, ZSTD_CHAINLOG_MIN, ZSTD_CHAINLOG_MAX);
     CLAMP(cParams.hashLog, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
     CLAMP(cParams.searchLog, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
     CLAMP(cParams.searchLength, ZSTD_SEARCHLENGTH_MIN, ZSTD_SEARCHLENGTH_MAX);
     CLAMP(cParams.targetLength, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
     if ((U32)(cParams.strategy) > (U32)ZSTD_btultra) cParams.strategy = ZSTD_btultra;
     return cParams;
 }
 
 /** ZSTD_cycleLog() :
  *  condition for correct operation : hashLog > 1 */
 static U32 ZSTD_cycleLog(U32 hashLog, ZSTD_strategy strat)
 {
     U32 const btScale = ((U32)strat >= (U32)ZSTD_btlazy2);
     return hashLog - btScale;
 }
 
 /** ZSTD_adjustCParams_internal() :
     optimize `cPar` for a given input (`srcSize` and `dictSize`).
     mostly downsizing to reduce memory consumption and initialization latency.
     Both `srcSize` and `dictSize` are optional (use 0 if unknown).
     Note : cPar is considered validated at this stage. Use ZSTD_checkCParams() to ensure that condition. */
 ZSTD_compressionParameters ZSTD_adjustCParams_internal(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize)
 {
     static const U64 minSrcSize = 513; /* (1<<9) + 1 */
     static const U64 maxWindowResize = 1ULL << (ZSTD_WINDOWLOG_MAX-1);
     assert(ZSTD_checkCParams(cPar)==0);
 
     if (dictSize && (srcSize+1<2) /* srcSize unknown */ )
         srcSize = minSrcSize;  /* presumed small when there is a dictionary */
     else if (srcSize == 0)
         srcSize = ZSTD_CONTENTSIZE_UNKNOWN;  /* 0 == unknown : presumed large */
 
     /* resize windowLog if input is small enough, to use less memory */
     if ( (srcSize < maxWindowResize)
       && (dictSize < maxWindowResize) )  {
         U32 const tSize = (U32)(srcSize + dictSize);
         static U32 const hashSizeMin = 1 << ZSTD_HASHLOG_MIN;
         U32 const srcLog = (tSize < hashSizeMin) ? ZSTD_HASHLOG_MIN :
                             ZSTD_highbit32(tSize-1) + 1;
         if (cPar.windowLog > srcLog) cPar.windowLog = srcLog;
     }
     if (cPar.hashLog > cPar.windowLog) cPar.hashLog = cPar.windowLog;
     {   U32 const cycleLog = ZSTD_cycleLog(cPar.chainLog, cPar.strategy);
         if (cycleLog > cPar.windowLog)
             cPar.chainLog -= (cycleLog - cPar.windowLog);
     }
 
     if (cPar.windowLog < ZSTD_WINDOWLOG_ABSOLUTEMIN)
         cPar.windowLog = ZSTD_WINDOWLOG_ABSOLUTEMIN;  /* required for frame header */
 
     return cPar;
 }
 
 ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize)
 {
     cPar = ZSTD_clampCParams(cPar);
     return ZSTD_adjustCParams_internal(cPar, srcSize, dictSize);
 }
 
 size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params)
 {
     /* Estimate CCtx size is supported for single-threaded compression only. */
     if (params->nbThreads > 1) { return ERROR(GENERIC); }
     {   ZSTD_compressionParameters const cParams =
                 ZSTD_getCParamsFromCCtxParams(*params, 0, 0);
         size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, (size_t)1 << cParams.windowLog);
         U32    const divider = (cParams.searchLength==3) ? 3 : 4;
         size_t const maxNbSeq = blockSize / divider;
         size_t const tokenSpace = blockSize + 11*maxNbSeq;
         size_t const chainSize =
                 (cParams.strategy == ZSTD_fast) ? 0 : ((size_t)1 << cParams.chainLog);
         size_t const hSize = ((size_t)1) << cParams.hashLog;
         U32    const hashLog3 = (cParams.searchLength>3) ?
                                 0 : MIN(ZSTD_HASHLOG3_MAX, cParams.windowLog);
         size_t const h3Size = ((size_t)1) << hashLog3;
         size_t const entropySpace = sizeof(ZSTD_entropyCTables_t);
         size_t const tableSpace = (chainSize + hSize + h3Size) * sizeof(U32);
 
         size_t const optBudget =
                 ((MaxML+1) + (MaxLL+1) + (MaxOff+1) + (1<ldmParams.enableLdm ?
             ZSTD_ldm_getTableSize(params->ldmParams.hashLog,
                                   params->ldmParams.bucketSizeLog) : 0;
 
         size_t const neededSpace = entropySpace + tableSpace + tokenSpace +
                                    optSpace + ldmSpace;
 
         DEBUGLOG(5, "sizeof(ZSTD_CCtx) : %u", (U32)sizeof(ZSTD_CCtx));
         DEBUGLOG(5, "estimate workSpace : %u", (U32)neededSpace);
         return sizeof(ZSTD_CCtx) + neededSpace;
     }
 }
 
 size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams)
 {
     ZSTD_CCtx_params const params = ZSTD_makeCCtxParamsFromCParams(cParams);
     return ZSTD_estimateCCtxSize_usingCCtxParams(¶ms);
 }
 
 size_t ZSTD_estimateCCtxSize(int compressionLevel)
 {
     ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, 0, 0);
     return ZSTD_estimateCCtxSize_usingCParams(cParams);
 }
 
 size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params)
 {
     if (params->nbThreads > 1) { return ERROR(GENERIC); }
     {   size_t const CCtxSize = ZSTD_estimateCCtxSize_usingCCtxParams(params);
         size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, (size_t)1 << params->cParams.windowLog);
         size_t const inBuffSize = ((size_t)1 << params->cParams.windowLog) + blockSize;
         size_t const outBuffSize = ZSTD_compressBound(blockSize) + 1;
         size_t const streamingSize = inBuffSize + outBuffSize;
 
         return CCtxSize + streamingSize;
     }
 }
 
 size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams)
 {
     ZSTD_CCtx_params const params = ZSTD_makeCCtxParamsFromCParams(cParams);
     return ZSTD_estimateCStreamSize_usingCCtxParams(¶ms);
 }
 
 size_t ZSTD_estimateCStreamSize(int compressionLevel) {
     ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, 0, 0);
     return ZSTD_estimateCStreamSize_usingCParams(cParams);
 }
 
 static U32 ZSTD_equivalentCParams(ZSTD_compressionParameters cParams1,
                                   ZSTD_compressionParameters cParams2)
 {
-    U32 bslog1 = MIN(cParams1.windowLog, ZSTD_BLOCKSIZELOG_MAX);
-    U32 bslog2 = MIN(cParams2.windowLog, ZSTD_BLOCKSIZELOG_MAX);
-    return (bslog1 == bslog2)   /* same block size */
-         & (cParams1.hashLog  == cParams2.hashLog)
+    return (cParams1.hashLog  == cParams2.hashLog)
          & (cParams1.chainLog == cParams2.chainLog)
          & (cParams1.strategy == cParams2.strategy)   /* opt parser space */
          & ((cParams1.searchLength==3) == (cParams2.searchLength==3));  /* hashlog3 space */
 }
 
 /** The parameters are equivalent if ldm is not enabled in both sets or
  *  all the parameters are equivalent. */
 static U32 ZSTD_equivalentLdmParams(ldmParams_t ldmParams1,
                                     ldmParams_t ldmParams2)
 {
     return (!ldmParams1.enableLdm && !ldmParams2.enableLdm) ||
            (ldmParams1.enableLdm == ldmParams2.enableLdm &&
             ldmParams1.hashLog == ldmParams2.hashLog &&
             ldmParams1.bucketSizeLog == ldmParams2.bucketSizeLog &&
             ldmParams1.minMatchLength == ldmParams2.minMatchLength &&
             ldmParams1.hashEveryLog == ldmParams2.hashEveryLog);
 }
 
+typedef enum { ZSTDb_not_buffered, ZSTDb_buffered } ZSTD_buffered_policy_e;
+
+/* ZSTD_sufficientBuff() :
+ * check internal buffers exist for streaming if buffPol == ZSTDb_buffered .
+ * Note : they are assumed to be correctly sized if ZSTD_equivalentCParams()==1 */
+static U32 ZSTD_sufficientBuff(size_t bufferSize1, size_t blockSize1,
+                            ZSTD_buffered_policy_e buffPol2,
+                            ZSTD_compressionParameters cParams2,
+                            U64 pledgedSrcSize)
+{
+    size_t const windowSize2 = MAX(1, (size_t)MIN(((U64)1 << cParams2.windowLog), pledgedSrcSize));
+    size_t const blockSize2 = MIN(ZSTD_BLOCKSIZE_MAX, windowSize2);
+    size_t const neededBufferSize2 = (buffPol2==ZSTDb_buffered) ? windowSize2 + blockSize2 : 0;
+    DEBUGLOG(4, "ZSTD_sufficientBuff: windowSize2=%u from wlog=%u",
+                (U32)windowSize2, cParams2.windowLog);
+    DEBUGLOG(4, "ZSTD_sufficientBuff: blockSize2 %u <=? blockSize1 %u",
+                (U32)blockSize2, (U32)blockSize1);
+    return (blockSize2 <= blockSize1) /* seqStore space depends on blockSize */
+         & (neededBufferSize2 <= bufferSize1);
+}
+
 /** Equivalence for resetCCtx purposes */
 static U32 ZSTD_equivalentParams(ZSTD_CCtx_params params1,
-                                 ZSTD_CCtx_params params2)
+                                 ZSTD_CCtx_params params2,
+                                 size_t buffSize1, size_t blockSize1,
+                                 ZSTD_buffered_policy_e buffPol2,
+                                 U64 pledgedSrcSize)
 {
+    DEBUGLOG(4, "ZSTD_equivalentParams: pledgedSrcSize=%u", (U32)pledgedSrcSize);
     return ZSTD_equivalentCParams(params1.cParams, params2.cParams) &&
-           ZSTD_equivalentLdmParams(params1.ldmParams, params2.ldmParams);
+           ZSTD_equivalentLdmParams(params1.ldmParams, params2.ldmParams) &&
+           ZSTD_sufficientBuff(buffSize1, blockSize1, buffPol2, params2.cParams, pledgedSrcSize);
 }
 
 /*! ZSTD_continueCCtx() :
  *  reuse CCtx without reset (note : requires no dictionary) */
 static size_t ZSTD_continueCCtx(ZSTD_CCtx* cctx, ZSTD_CCtx_params params, U64 pledgedSrcSize)
 {
     U32 const end = (U32)(cctx->nextSrc - cctx->base);
-    DEBUGLOG(4, "continue mode");
+    size_t const windowSize = MAX(1, (size_t)MIN(((U64)1 << params.cParams.windowLog), pledgedSrcSize));
+    size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, windowSize);
+    DEBUGLOG(4, "ZSTD_continueCCtx");
+
+    cctx->blockSize = blockSize;   /* previous block size could be different even for same windowLog, due to pledgedSrcSize */
     cctx->appliedParams = params;
     cctx->pledgedSrcSizePlusOne = pledgedSrcSize+1;
     cctx->consumedSrcSize = 0;
     if (pledgedSrcSize == ZSTD_CONTENTSIZE_UNKNOWN)
         cctx->appliedParams.fParams.contentSizeFlag = 0;
     DEBUGLOG(4, "pledged content size : %u ; flag : %u",
         (U32)pledgedSrcSize, cctx->appliedParams.fParams.contentSizeFlag);
     cctx->lowLimit = end;
     cctx->dictLimit = end;
     cctx->nextToUpdate = end+1;
     cctx->stage = ZSTDcs_init;
     cctx->dictID = 0;
     cctx->loadedDictEnd = 0;
     { int i; for (i=0; iseqStore.rep[i] = repStartValue[i]; }
     cctx->optState.litLengthSum = 0;  /* force reset of btopt stats */
     XXH64_reset(&cctx->xxhState, 0);
     return 0;
 }
 
 typedef enum { ZSTDcrp_continue, ZSTDcrp_noMemset } ZSTD_compResetPolicy_e;
-typedef enum { ZSTDb_not_buffered, ZSTDb_buffered } ZSTD_buffered_policy_e;
 
 /*! ZSTD_resetCCtx_internal() :
     note : `params` are assumed fully validated at this stage */
 static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
                                       ZSTD_CCtx_params params, U64 pledgedSrcSize,
                                       ZSTD_compResetPolicy_e const crp,
                                       ZSTD_buffered_policy_e const zbuff)
 {
-    DEBUGLOG(4, "ZSTD_resetCCtx_internal");
+    DEBUGLOG(4, "ZSTD_resetCCtx_internal: pledgedSrcSize=%u, wlog=%u",
+                (U32)pledgedSrcSize, params.cParams.windowLog);
     assert(!ZSTD_isError(ZSTD_checkCParams(params.cParams)));
-    DEBUGLOG(4, "pledgedSrcSize: %u", (U32)pledgedSrcSize);
 
     if (crp == ZSTDcrp_continue) {
-        if (ZSTD_equivalentParams(params, zc->appliedParams)) {
-            DEBUGLOG(4, "ZSTD_equivalentParams()==1");
+        if (ZSTD_equivalentParams(zc->appliedParams, params,
+                                zc->inBuffSize, zc->blockSize,
+                                zbuff, pledgedSrcSize)) {
+            DEBUGLOG(4, "ZSTD_equivalentParams()==1 -> continue mode (wLog1=%u, blockSize1=%u)",
+                        zc->appliedParams.cParams.windowLog, (U32)zc->blockSize);
             assert(!(params.ldmParams.enableLdm &&
                      params.ldmParams.hashEveryLog == ZSTD_LDM_HASHEVERYLOG_NOTSET));
             zc->entropy->hufCTable_repeatMode = HUF_repeat_none;
             zc->entropy->offcode_repeatMode = FSE_repeat_none;
             zc->entropy->matchlength_repeatMode = FSE_repeat_none;
             zc->entropy->litlength_repeatMode = FSE_repeat_none;
             return ZSTD_continueCCtx(zc, params, pledgedSrcSize);
     }   }
+    DEBUGLOG(4, "ZSTD_equivalentParams()==0 -> reset CCtx");
 
     if (params.ldmParams.enableLdm) {
         /* Adjust long distance matching parameters */
         ZSTD_ldm_adjustParameters(¶ms.ldmParams, params.cParams.windowLog);
         assert(params.ldmParams.hashLog >= params.ldmParams.bucketSizeLog);
         assert(params.ldmParams.hashEveryLog < 32);
         zc->ldmState.hashPower =
                 ZSTD_ldm_getHashPower(params.ldmParams.minMatchLength);
     }
 
-    {   size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, (size_t)1 << params.cParams.windowLog);
+    {   size_t const windowSize = MAX(1, (size_t)MIN(((U64)1 << params.cParams.windowLog), pledgedSrcSize));
+        size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, windowSize);
         U32    const divider = (params.cParams.searchLength==3) ? 3 : 4;
         size_t const maxNbSeq = blockSize / divider;
         size_t const tokenSpace = blockSize + 11*maxNbSeq;
         size_t const chainSize = (params.cParams.strategy == ZSTD_fast) ?
                                 0 : ((size_t)1 << params.cParams.chainLog);
         size_t const hSize = ((size_t)1) << params.cParams.hashLog;
         U32    const hashLog3 = (params.cParams.searchLength>3) ?
                                 0 : MIN(ZSTD_HASHLOG3_MAX, params.cParams.windowLog);
         size_t const h3Size = ((size_t)1) << hashLog3;
         size_t const tableSpace = (chainSize + hSize + h3Size) * sizeof(U32);
         size_t const buffOutSize = (zbuff==ZSTDb_buffered) ? ZSTD_compressBound(blockSize)+1 : 0;
-        size_t const buffInSize = (zbuff==ZSTDb_buffered) ? ((size_t)1 << params.cParams.windowLog) + blockSize : 0;
+        size_t const buffInSize = (zbuff==ZSTDb_buffered) ? windowSize + blockSize : 0;
         void* ptr;
 
         /* Check if workSpace is large enough, alloc a new one if needed */
         {   size_t const entropySpace = sizeof(ZSTD_entropyCTables_t);
             size_t const optPotentialSpace = ((MaxML+1) + (MaxLL+1) + (MaxOff+1) + (1<>10), (U32)(tableSpace>>10), (U32)(bufferSpace>>10));
+            DEBUGLOG(4, "chainSize: %u - hSize: %u - h3Size: %u - windowSize: %u - blockSize: %u",
+                        (U32)chainSize, (U32)hSize, (U32)h3Size, (U32)windowSize, (U32)blockSize);
 
             if (zc->workSpaceSize < neededSpace) {  /* too small : resize */
-                DEBUGLOG(5, "Need to update workSpaceSize from %uK to %uK \n",
-                            (unsigned)zc->workSpaceSize>>10,
-                            (unsigned)neededSpace>>10);
+                DEBUGLOG(4, "Need to update workSpaceSize from %uK to %uK",
+                            (unsigned)(zc->workSpaceSize>>10),
+                            (unsigned)(neededSpace>>10));
                 /* static cctx : no resize, error out */
                 if (zc->staticSize) return ERROR(memory_allocation);
 
                 zc->workSpaceSize = 0;
                 ZSTD_free(zc->workSpace, zc->customMem);
                 zc->workSpace = ZSTD_malloc(neededSpace, zc->customMem);
                 if (zc->workSpace == NULL) return ERROR(memory_allocation);
                 zc->workSpaceSize = neededSpace;
                 ptr = zc->workSpace;
 
                 /* entropy space */
                 assert(((size_t)zc->workSpace & 3) == 0);   /* ensure correct alignment */
                 assert(zc->workSpaceSize >= sizeof(ZSTD_entropyCTables_t));
                 zc->entropy = (ZSTD_entropyCTables_t*)zc->workSpace;
         }   }
 
         /* init params */
         zc->appliedParams = params;
         zc->pledgedSrcSizePlusOne = pledgedSrcSize+1;
         zc->consumedSrcSize = 0;
         if (pledgedSrcSize == ZSTD_CONTENTSIZE_UNKNOWN)
             zc->appliedParams.fParams.contentSizeFlag = 0;
-        DEBUGLOG(5, "pledged content size : %u ; flag : %u",
+        DEBUGLOG(4, "pledged content size : %u ; flag : %u",
             (U32)pledgedSrcSize, zc->appliedParams.fParams.contentSizeFlag);
         zc->blockSize = blockSize;
 
         XXH64_reset(&zc->xxhState, 0);
         zc->stage = ZSTDcs_init;
         zc->dictID = 0;
         zc->loadedDictEnd = 0;
         zc->entropy->hufCTable_repeatMode = HUF_repeat_none;
         zc->entropy->offcode_repeatMode = FSE_repeat_none;
         zc->entropy->matchlength_repeatMode = FSE_repeat_none;
         zc->entropy->litlength_repeatMode = FSE_repeat_none;
         zc->nextToUpdate = 1;
         zc->nextSrc = NULL;
         zc->base = NULL;
         zc->dictBase = NULL;
         zc->dictLimit = 0;
         zc->lowLimit = 0;
         { int i; for (i=0; iseqStore.rep[i] = repStartValue[i]; }
         zc->hashLog3 = hashLog3;
         zc->optState.litLengthSum = 0;
 
         ptr = zc->entropy + 1;
 
         /* opt parser space */
         if ((params.cParams.strategy == ZSTD_btopt) || (params.cParams.strategy == ZSTD_btultra)) {
-            DEBUGLOG(5, "reserving optimal parser space");
+            DEBUGLOG(4, "reserving optimal parser space");
             assert(((size_t)ptr & 3) == 0);  /* ensure ptr is properly aligned */
             zc->optState.litFreq = (U32*)ptr;
             zc->optState.litLengthFreq = zc->optState.litFreq + (1<optState.matchLengthFreq = zc->optState.litLengthFreq + (MaxLL+1);
             zc->optState.offCodeFreq = zc->optState.matchLengthFreq + (MaxML+1);
             ptr = zc->optState.offCodeFreq + (MaxOff+1);
             zc->optState.matchTable = (ZSTD_match_t*)ptr;
             ptr = zc->optState.matchTable + ZSTD_OPT_NUM+1;
             zc->optState.priceTable = (ZSTD_optimal_t*)ptr;
             ptr = zc->optState.priceTable + ZSTD_OPT_NUM+1;
         }
 
         /* ldm hash table */
         /* initialize bucketOffsets table later for pointer alignment */
         if (params.ldmParams.enableLdm) {
             size_t const ldmHSize = ((size_t)1) << params.ldmParams.hashLog;
             memset(ptr, 0, ldmHSize * sizeof(ldmEntry_t));
             assert(((size_t)ptr & 3) == 0); /* ensure ptr is properly aligned */
             zc->ldmState.hashTable = (ldmEntry_t*)ptr;
             ptr = zc->ldmState.hashTable + ldmHSize;
         }
 
         /* table Space */
+        DEBUGLOG(4, "reset table : %u", crp!=ZSTDcrp_noMemset);
         if (crp!=ZSTDcrp_noMemset) memset(ptr, 0, tableSpace);   /* reset tables only */
         assert(((size_t)ptr & 3) == 0);  /* ensure ptr is properly aligned */
         zc->hashTable = (U32*)(ptr);
         zc->chainTable = zc->hashTable + hSize;
         zc->hashTable3 = zc->chainTable + chainSize;
         ptr = zc->hashTable3 + h3Size;
 
         /* sequences storage */
         zc->seqStore.sequencesStart = (seqDef*)ptr;
         ptr = zc->seqStore.sequencesStart + maxNbSeq;
         zc->seqStore.llCode = (BYTE*) ptr;
         zc->seqStore.mlCode = zc->seqStore.llCode + maxNbSeq;
         zc->seqStore.ofCode = zc->seqStore.mlCode + maxNbSeq;
         zc->seqStore.litStart = zc->seqStore.ofCode + maxNbSeq;
         ptr = zc->seqStore.litStart + blockSize;
 
         /* ldm bucketOffsets table */
         if (params.ldmParams.enableLdm) {
             size_t const ldmBucketSize =
                   ((size_t)1) << (params.ldmParams.hashLog -
                                   params.ldmParams.bucketSizeLog);
             memset(ptr, 0, ldmBucketSize);
             zc->ldmState.bucketOffsets = (BYTE*)ptr;
             ptr = zc->ldmState.bucketOffsets + ldmBucketSize;
         }
 
         /* buffers */
         zc->inBuffSize = buffInSize;
         zc->inBuff = (char*)ptr;
         zc->outBuffSize = buffOutSize;
         zc->outBuff = zc->inBuff + buffInSize;
 
         return 0;
     }
 }
 
 /* ZSTD_invalidateRepCodes() :
  * ensures next compression will not use repcodes from previous block.
  * Note : only works with regular variant;
  *        do not use with extDict variant ! */
 void ZSTD_invalidateRepCodes(ZSTD_CCtx* cctx) {
     int i;
     for (i=0; iseqStore.rep[i] = 0;
 }
 
 
 /*! ZSTD_copyCCtx_internal() :
  *  Duplicate an existing context `srcCCtx` into another one `dstCCtx`.
- *  The "context", in this case, refers to the hash and chain tables, entropy
- *  tables, and dictionary offsets.
  *  Only works during stage ZSTDcs_init (i.e. after creation, but before first call to ZSTD_compressContinue()).
- *  pledgedSrcSize=0 means "empty" if fParams.contentSizeFlag=1
- *  @return : 0, or an error code */
+ *  The "context", in this case, refers to the hash and chain tables,
+ *  entropy tables, and dictionary references.
+ * `windowLog` value is enforced if != 0, otherwise value is copied from srcCCtx.
+ * @return : 0, or an error code */
 static size_t ZSTD_copyCCtx_internal(ZSTD_CCtx* dstCCtx,
                             const ZSTD_CCtx* srcCCtx,
+                            unsigned windowLog,
                             ZSTD_frameParameters fParams,
-                            unsigned long long pledgedSrcSize,
+                            U64 pledgedSrcSize,
                             ZSTD_buffered_policy_e zbuff)
 {
     DEBUGLOG(5, "ZSTD_copyCCtx_internal");
     if (srcCCtx->stage!=ZSTDcs_init) return ERROR(stage_wrong);
 
     memcpy(&dstCCtx->customMem, &srcCCtx->customMem, sizeof(ZSTD_customMem));
     {   ZSTD_CCtx_params params = dstCCtx->requestedParams;
         /* Copy only compression parameters related to tables. */
         params.cParams = srcCCtx->appliedParams.cParams;
+        if (windowLog) params.cParams.windowLog = windowLog;
         params.fParams = fParams;
         ZSTD_resetCCtx_internal(dstCCtx, params, pledgedSrcSize,
                                 ZSTDcrp_noMemset, zbuff);
     }
 
     /* copy tables */
     {   size_t const chainSize = (srcCCtx->appliedParams.cParams.strategy == ZSTD_fast) ? 0 : ((size_t)1 << srcCCtx->appliedParams.cParams.chainLog);
         size_t const hSize =  (size_t)1 << srcCCtx->appliedParams.cParams.hashLog;
         size_t const h3Size = (size_t)1 << srcCCtx->hashLog3;
         size_t const tableSpace = (chainSize + hSize + h3Size) * sizeof(U32);
         assert((U32*)dstCCtx->chainTable == (U32*)dstCCtx->hashTable + hSize);  /* chainTable must follow hashTable */
         assert((U32*)dstCCtx->hashTable3 == (U32*)dstCCtx->chainTable + chainSize);
         memcpy(dstCCtx->hashTable, srcCCtx->hashTable, tableSpace);   /* presumes all tables follow each other */
     }
 
     /* copy dictionary offsets */
     dstCCtx->nextToUpdate = srcCCtx->nextToUpdate;
     dstCCtx->nextToUpdate3= srcCCtx->nextToUpdate3;
     dstCCtx->nextSrc      = srcCCtx->nextSrc;
     dstCCtx->base         = srcCCtx->base;
     dstCCtx->dictBase     = srcCCtx->dictBase;
     dstCCtx->dictLimit    = srcCCtx->dictLimit;
     dstCCtx->lowLimit     = srcCCtx->lowLimit;
     dstCCtx->loadedDictEnd= srcCCtx->loadedDictEnd;
     dstCCtx->dictID       = srcCCtx->dictID;
 
     /* copy entropy tables */
     memcpy(dstCCtx->entropy, srcCCtx->entropy, sizeof(ZSTD_entropyCTables_t));
+    /* copy repcodes */
+    {
+        int i;
+        for (i = 0; i < ZSTD_REP_NUM; ++i)
+            dstCCtx->seqStore.rep[i] = srcCCtx->seqStore.rep[i];
+    }
 
     return 0;
 }
 
 /*! ZSTD_copyCCtx() :
  *  Duplicate an existing context `srcCCtx` into another one `dstCCtx`.
  *  Only works during stage ZSTDcs_init (i.e. after creation, but before first call to ZSTD_compressContinue()).
  *  pledgedSrcSize==0 means "unknown".
 *   @return : 0, or an error code */
 size_t ZSTD_copyCCtx(ZSTD_CCtx* dstCCtx, const ZSTD_CCtx* srcCCtx, unsigned long long pledgedSrcSize)
 {
     ZSTD_frameParameters fParams = { 1 /*content*/, 0 /*checksum*/, 0 /*noDictID*/ };
     ZSTD_buffered_policy_e const zbuff = (ZSTD_buffered_policy_e)(srcCCtx->inBuffSize>0);
     ZSTD_STATIC_ASSERT((U32)ZSTDb_buffered==1);
-    fParams.contentSizeFlag = pledgedSrcSize>0;
+    if (pledgedSrcSize==0) pledgedSrcSize = ZSTD_CONTENTSIZE_UNKNOWN;
+    fParams.contentSizeFlag = (pledgedSrcSize != ZSTD_CONTENTSIZE_UNKNOWN);
 
-    return ZSTD_copyCCtx_internal(dstCCtx, srcCCtx, fParams, pledgedSrcSize, zbuff);
+    return ZSTD_copyCCtx_internal(dstCCtx, srcCCtx,
+                                0 /*windowLog from srcCCtx*/, fParams, pledgedSrcSize,
+                                zbuff);
 }
 
 
 /*! ZSTD_reduceTable() :
  *  reduce table indexes by `reducerValue` */
 static void ZSTD_reduceTable (U32* const table, U32 const size, U32 const reducerValue)
 {
     U32 u;
     for (u=0 ; u < size ; u++) {
         if (table[u] < reducerValue) table[u] = 0;
         else table[u] -= reducerValue;
     }
 }
 
 /*! ZSTD_ldm_reduceTable() :
  *  reduce table indexes by `reducerValue` */
 static void ZSTD_ldm_reduceTable(ldmEntry_t* const table, U32 const size,
                                  U32 const reducerValue)
 {
     U32 u;
     for (u = 0; u < size; u++) {
         if (table[u].offset < reducerValue) table[u].offset = 0;
         else table[u].offset -= reducerValue;
     }
 }
 
 /*! ZSTD_reduceIndex() :
 *   rescale all indexes to avoid future overflow (indexes are U32) */
 static void ZSTD_reduceIndex (ZSTD_CCtx* zc, const U32 reducerValue)
 {
     { U32 const hSize = (U32)1 << zc->appliedParams.cParams.hashLog;
       ZSTD_reduceTable(zc->hashTable, hSize, reducerValue); }
 
     { U32 const chainSize = (zc->appliedParams.cParams.strategy == ZSTD_fast) ? 0 : ((U32)1 << zc->appliedParams.cParams.chainLog);
       ZSTD_reduceTable(zc->chainTable, chainSize, reducerValue); }
 
     { U32 const h3Size = (zc->hashLog3) ? (U32)1 << zc->hashLog3 : 0;
       ZSTD_reduceTable(zc->hashTable3, h3Size, reducerValue); }
 
     { if (zc->appliedParams.ldmParams.enableLdm) {
           U32 const ldmHSize = (U32)1 << zc->appliedParams.ldmParams.hashLog;
           ZSTD_ldm_reduceTable(zc->ldmState.hashTable, ldmHSize, reducerValue);
       }
     }
 }
 
 
 /*-*******************************************************
 *  Block entropic compression
 *********************************************************/
 
 /* See doc/zstd_compression_format.md for detailed format description */
 
 size_t ZSTD_noCompressBlock (void* dst, size_t dstCapacity, const void* src, size_t srcSize)
 {
     if (srcSize + ZSTD_blockHeaderSize > dstCapacity) return ERROR(dstSize_tooSmall);
     memcpy((BYTE*)dst + ZSTD_blockHeaderSize, src, srcSize);
     MEM_writeLE24(dst, (U32)(srcSize << 2) + (U32)bt_raw);
     return ZSTD_blockHeaderSize+srcSize;
 }
 
 
 static size_t ZSTD_noCompressLiterals (void* dst, size_t dstCapacity, const void* src, size_t srcSize)
 {
     BYTE* const ostart = (BYTE* const)dst;
     U32   const flSize = 1 + (srcSize>31) + (srcSize>4095);
 
     if (srcSize + flSize > dstCapacity) return ERROR(dstSize_tooSmall);
 
     switch(flSize)
     {
         case 1: /* 2 - 1 - 5 */
             ostart[0] = (BYTE)((U32)set_basic + (srcSize<<3));
             break;
         case 2: /* 2 - 2 - 12 */
             MEM_writeLE16(ostart, (U16)((U32)set_basic + (1<<2) + (srcSize<<4)));
             break;
         case 3: /* 2 - 2 - 20 */
             MEM_writeLE32(ostart, (U32)((U32)set_basic + (3<<2) + (srcSize<<4)));
             break;
         default:   /* not necessary : flSize is {1,2,3} */
             assert(0);
     }
 
     memcpy(ostart + flSize, src, srcSize);
     return srcSize + flSize;
 }
 
 static size_t ZSTD_compressRleLiteralsBlock (void* dst, size_t dstCapacity, const void* src, size_t srcSize)
 {
     BYTE* const ostart = (BYTE* const)dst;
     U32   const flSize = 1 + (srcSize>31) + (srcSize>4095);
 
     (void)dstCapacity;  /* dstCapacity already guaranteed to be >=4, hence large enough */
 
     switch(flSize)
     {
         case 1: /* 2 - 1 - 5 */
             ostart[0] = (BYTE)((U32)set_rle + (srcSize<<3));
             break;
         case 2: /* 2 - 2 - 12 */
             MEM_writeLE16(ostart, (U16)((U32)set_rle + (1<<2) + (srcSize<<4)));
             break;
         case 3: /* 2 - 2 - 20 */
             MEM_writeLE32(ostart, (U32)((U32)set_rle + (3<<2) + (srcSize<<4)));
             break;
         default:   /* not necessary : flSize is {1,2,3} */
             assert(0);
     }
 
     ostart[flSize] = *(const BYTE*)src;
     return flSize+1;
 }
 
 
 static size_t ZSTD_minGain(size_t srcSize) { return (srcSize >> 6) + 2; }
 
 static size_t ZSTD_compressLiterals (ZSTD_entropyCTables_t * entropy,
                                      ZSTD_strategy strategy,
                                      void* dst, size_t dstCapacity,
                                const void* src, size_t srcSize)
 {
     size_t const minGain = ZSTD_minGain(srcSize);
     size_t const lhSize = 3 + (srcSize >= 1 KB) + (srcSize >= 16 KB);
     BYTE*  const ostart = (BYTE*)dst;
     U32 singleStream = srcSize < 256;
     symbolEncodingType_e hType = set_compressed;
     size_t cLitSize;
 
 
     /* small ? don't even attempt compression (speed opt) */
 #   define LITERAL_NOENTROPY 63
     {   size_t const minLitSize = entropy->hufCTable_repeatMode == HUF_repeat_valid ? 6 : LITERAL_NOENTROPY;
         if (srcSize <= minLitSize) return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
     }
 
     if (dstCapacity < lhSize+1) return ERROR(dstSize_tooSmall);   /* not enough space for compression */
     {   HUF_repeat repeat = entropy->hufCTable_repeatMode;
         int const preferRepeat = strategy < ZSTD_lazy ? srcSize <= 1024 : 0;
         if (repeat == HUF_repeat_valid && lhSize == 3) singleStream = 1;
         cLitSize = singleStream ? HUF_compress1X_repeat(ostart+lhSize, dstCapacity-lhSize, src, srcSize, 255, 11,
                                       entropy->workspace, sizeof(entropy->workspace), (HUF_CElt*)entropy->hufCTable, &repeat, preferRepeat)
                                 : HUF_compress4X_repeat(ostart+lhSize, dstCapacity-lhSize, src, srcSize, 255, 11,
                                       entropy->workspace, sizeof(entropy->workspace), (HUF_CElt*)entropy->hufCTable, &repeat, preferRepeat);
         if (repeat != HUF_repeat_none) { hType = set_repeat; }    /* reused the existing table */
         else { entropy->hufCTable_repeatMode = HUF_repeat_check; }       /* now have a table to reuse */
     }
 
     if ((cLitSize==0) | (cLitSize >= srcSize - minGain) | ERR_isError(cLitSize)) {
         entropy->hufCTable_repeatMode = HUF_repeat_none;
         return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
     }
     if (cLitSize==1) {
         entropy->hufCTable_repeatMode = HUF_repeat_none;
         return ZSTD_compressRleLiteralsBlock(dst, dstCapacity, src, srcSize);
     }
 
     /* Build header */
     switch(lhSize)
     {
     case 3: /* 2 - 2 - 10 - 10 */
         {   U32 const lhc = hType + ((!singleStream) << 2) + ((U32)srcSize<<4) + ((U32)cLitSize<<14);
             MEM_writeLE24(ostart, lhc);
             break;
         }
     case 4: /* 2 - 2 - 14 - 14 */
         {   U32 const lhc = hType + (2 << 2) + ((U32)srcSize<<4) + ((U32)cLitSize<<18);
             MEM_writeLE32(ostart, lhc);
             break;
         }
     case 5: /* 2 - 2 - 18 - 18 */
         {   U32 const lhc = hType + (3 << 2) + ((U32)srcSize<<4) + ((U32)cLitSize<<22);
             MEM_writeLE32(ostart, lhc);
             ostart[4] = (BYTE)(cLitSize >> 10);
             break;
         }
-    default:   /* not possible : lhSize is {3,4,5} */
+    default:  /* not possible : lhSize is {3,4,5} */
         assert(0);
     }
     return lhSize+cLitSize;
 }
 
 
 void ZSTD_seqToCodes(const seqStore_t* seqStorePtr)
 {
-    BYTE const LL_deltaCode = 19;
-    BYTE const ML_deltaCode = 36;
     const seqDef* const sequences = seqStorePtr->sequencesStart;
     BYTE* const llCodeTable = seqStorePtr->llCode;
     BYTE* const ofCodeTable = seqStorePtr->ofCode;
     BYTE* const mlCodeTable = seqStorePtr->mlCode;
     U32 const nbSeq = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
     U32 u;
     for (u=0; u 63) ? (BYTE)ZSTD_highbit32(llv) + LL_deltaCode : LL_Code[llv];
+        llCodeTable[u] = (BYTE)ZSTD_LLcode(llv);
         ofCodeTable[u] = (BYTE)ZSTD_highbit32(sequences[u].offset);
-        mlCodeTable[u] = (mlv>127) ? (BYTE)ZSTD_highbit32(mlv) + ML_deltaCode : ML_Code[mlv];
+        mlCodeTable[u] = (BYTE)ZSTD_MLcode(mlv);
     }
     if (seqStorePtr->longLengthID==1)
         llCodeTable[seqStorePtr->longLengthPos] = MaxLL;
     if (seqStorePtr->longLengthID==2)
         mlCodeTable[seqStorePtr->longLengthPos] = MaxML;
 }
 
 typedef enum {
     ZSTD_defaultDisallowed = 0,
     ZSTD_defaultAllowed = 1
 } ZSTD_defaultPolicy_e;
 
-MEM_STATIC symbolEncodingType_e ZSTD_selectEncodingType(
+MEM_STATIC
+symbolEncodingType_e ZSTD_selectEncodingType(
         FSE_repeat* repeatMode, size_t const mostFrequent, size_t nbSeq,
         U32 defaultNormLog, ZSTD_defaultPolicy_e const isDefaultAllowed)
 {
 #define MIN_SEQ_FOR_DYNAMIC_FSE   64
 #define MAX_SEQ_FOR_STATIC_FSE  1000
     ZSTD_STATIC_ASSERT(ZSTD_defaultDisallowed == 0 && ZSTD_defaultAllowed != 0);
     if ((mostFrequent == nbSeq) && (!isDefaultAllowed || nbSeq > 2)) {
+        DEBUGLOG(5, "Selected set_rle");
         /* Prefer set_basic over set_rle when there are 2 or less symbols,
          * since RLE uses 1 byte, but set_basic uses 5-6 bits per symbol.
          * If basic encoding isn't possible, always choose RLE.
          */
         *repeatMode = FSE_repeat_check;
         return set_rle;
     }
-    if (isDefaultAllowed && (*repeatMode == FSE_repeat_valid) && (nbSeq < MAX_SEQ_FOR_STATIC_FSE)) {
+    if ( isDefaultAllowed
+      && (*repeatMode == FSE_repeat_valid) && (nbSeq < MAX_SEQ_FOR_STATIC_FSE)) {
+        DEBUGLOG(5, "Selected set_repeat");
         return set_repeat;
     }
-    if (isDefaultAllowed && ((nbSeq < MIN_SEQ_FOR_DYNAMIC_FSE) || (mostFrequent < (nbSeq >> (defaultNormLog-1))))) {
-        *repeatMode = FSE_repeat_valid;
+    if ( isDefaultAllowed
+      && ((nbSeq < MIN_SEQ_FOR_DYNAMIC_FSE) || (mostFrequent < (nbSeq >> (defaultNormLog-1)))) ) {
+        DEBUGLOG(5, "Selected set_basic");
+        /* The format allows default tables to be repeated, but it isn't useful.
+         * When using simple heuristics to select encoding type, we don't want
+         * to confuse these tables with dictionaries. When running more careful
+         * analysis, we don't need to waste time checking both repeating tables
+         * and default tables.
+         */
+        *repeatMode = FSE_repeat_none;
         return set_basic;
     }
+    DEBUGLOG(5, "Selected set_compressed");
     *repeatMode = FSE_repeat_check;
     return set_compressed;
 }
 
-MEM_STATIC size_t ZSTD_buildCTable(void* dst, size_t dstCapacity,
+MEM_STATIC
+size_t ZSTD_buildCTable(void* dst, size_t dstCapacity,
         FSE_CTable* CTable, U32 FSELog, symbolEncodingType_e type,
         U32* count, U32 max,
         BYTE const* codeTable, size_t nbSeq,
         S16 const* defaultNorm, U32 defaultNormLog, U32 defaultMax,
         void* workspace, size_t workspaceSize)
 {
     BYTE* op = (BYTE*)dst;
     BYTE const* const oend = op + dstCapacity;
 
     switch (type) {
     case set_rle:
         *op = codeTable[0];
         CHECK_F(FSE_buildCTable_rle(CTable, (BYTE)max));
         return 1;
     case set_repeat:
         return 0;
     case set_basic:
-        CHECK_F(FSE_buildCTable_wksp(CTable, defaultNorm, defaultMax, defaultNormLog, workspace, workspaceSize));
+        CHECK_F(FSE_buildCTable_wksp(CTable, defaultNorm, defaultMax, defaultNormLog, workspace, workspaceSize));  /* note : could be pre-calculated */
         return 0;
     case set_compressed: {
         S16 norm[MaxSeq + 1];
         size_t nbSeq_1 = nbSeq;
         const U32 tableLog = FSE_optimalTableLog(FSELog, nbSeq, max);
         if (count[codeTable[nbSeq-1]] > 1) {
             count[codeTable[nbSeq-1]]--;
             nbSeq_1--;
         }
         assert(nbSeq_1 > 1);
         CHECK_F(FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max));
         {   size_t const NCountSize = FSE_writeNCount(op, oend - op, norm, max, tableLog);   /* overflow protected */
             if (FSE_isError(NCountSize)) return NCountSize;
             CHECK_F(FSE_buildCTable_wksp(CTable, norm, max, tableLog, workspace, workspaceSize));
             return NCountSize;
         }
     }
     default: return assert(0), ERROR(GENERIC);
     }
 }
 
-MEM_STATIC size_t ZSTD_encodeSequences(void* dst, size_t dstCapacity,
-    FSE_CTable const* CTable_MatchLength, BYTE const* mlCodeTable,
-    FSE_CTable const* CTable_OffsetBits, BYTE const* ofCodeTable,
-    FSE_CTable const* CTable_LitLength, BYTE const* llCodeTable,
-    seqDef const* sequences, size_t nbSeq, int longOffsets)
+MEM_STATIC
+size_t ZSTD_encodeSequences(
+            void* dst, size_t dstCapacity,
+            FSE_CTable const* CTable_MatchLength, BYTE const* mlCodeTable,
+            FSE_CTable const* CTable_OffsetBits, BYTE const* ofCodeTable,
+            FSE_CTable const* CTable_LitLength, BYTE const* llCodeTable,
+            seqDef const* sequences, size_t nbSeq, int longOffsets)
 {
     BIT_CStream_t blockStream;
     FSE_CState_t  stateMatchLength;
     FSE_CState_t  stateOffsetBits;
     FSE_CState_t  stateLitLength;
 
     CHECK_E(BIT_initCStream(&blockStream, dst, dstCapacity), dstSize_tooSmall); /* not enough space remaining */
 
     /* first symbols */
     FSE_initCState2(&stateMatchLength, CTable_MatchLength, mlCodeTable[nbSeq-1]);
     FSE_initCState2(&stateOffsetBits,  CTable_OffsetBits,  ofCodeTable[nbSeq-1]);
     FSE_initCState2(&stateLitLength,   CTable_LitLength,   llCodeTable[nbSeq-1]);
     BIT_addBits(&blockStream, sequences[nbSeq-1].litLength, LL_bits[llCodeTable[nbSeq-1]]);
     if (MEM_32bits()) BIT_flushBits(&blockStream);
     BIT_addBits(&blockStream, sequences[nbSeq-1].matchLength, ML_bits[mlCodeTable[nbSeq-1]]);
     if (MEM_32bits()) BIT_flushBits(&blockStream);
     if (longOffsets) {
         U32 const ofBits = ofCodeTable[nbSeq-1];
         int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN-1);
         if (extraBits) {
             BIT_addBits(&blockStream, sequences[nbSeq-1].offset, extraBits);
             BIT_flushBits(&blockStream);
         }
         BIT_addBits(&blockStream, sequences[nbSeq-1].offset >> extraBits,
                     ofBits - extraBits);
     } else {
         BIT_addBits(&blockStream, sequences[nbSeq-1].offset, ofCodeTable[nbSeq-1]);
     }
     BIT_flushBits(&blockStream);
 
     {   size_t n;
         for (n=nbSeq-2 ; n= 64-7-(LLFSELog+MLFSELog+OffFSELog)))
                 BIT_flushBits(&blockStream);                                /* (7)*/
             BIT_addBits(&blockStream, sequences[n].litLength, llBits);
             if (MEM_32bits() && ((llBits+mlBits)>24)) BIT_flushBits(&blockStream);
             BIT_addBits(&blockStream, sequences[n].matchLength, mlBits);
             if (MEM_32bits() || (ofBits+mlBits+llBits > 56)) BIT_flushBits(&blockStream);
             if (longOffsets) {
                 int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN-1);
                 if (extraBits) {
                     BIT_addBits(&blockStream, sequences[n].offset, extraBits);
                     BIT_flushBits(&blockStream);                            /* (7)*/
                 }
                 BIT_addBits(&blockStream, sequences[n].offset >> extraBits,
                             ofBits - extraBits);                            /* 31 */
             } else {
                 BIT_addBits(&blockStream, sequences[n].offset, ofBits);     /* 31 */
             }
             BIT_flushBits(&blockStream);                                    /* (7)*/
     }   }
 
     FSE_flushCState(&blockStream, &stateMatchLength);
     FSE_flushCState(&blockStream, &stateOffsetBits);
     FSE_flushCState(&blockStream, &stateLitLength);
 
     {   size_t const streamSize = BIT_closeCStream(&blockStream);
         if (streamSize==0) return ERROR(dstSize_tooSmall);   /* not enough space */
         return streamSize;
     }
 }
 
 MEM_STATIC size_t ZSTD_compressSequences_internal(seqStore_t* seqStorePtr,
                               ZSTD_entropyCTables_t* entropy,
                               ZSTD_compressionParameters const* cParams,
                               void* dst, size_t dstCapacity)
 {
     const int longOffsets = cParams->windowLog > STREAM_ACCUMULATOR_MIN;
     U32 count[MaxSeq+1];
     FSE_CTable* CTable_LitLength = entropy->litlengthCTable;
     FSE_CTable* CTable_OffsetBits = entropy->offcodeCTable;
     FSE_CTable* CTable_MatchLength = entropy->matchlengthCTable;
     U32 LLtype, Offtype, MLtype;   /* compressed, raw or rle */
     const seqDef* const sequences = seqStorePtr->sequencesStart;
     const BYTE* const ofCodeTable = seqStorePtr->ofCode;
     const BYTE* const llCodeTable = seqStorePtr->llCode;
     const BYTE* const mlCodeTable = seqStorePtr->mlCode;
     BYTE* const ostart = (BYTE*)dst;
     BYTE* const oend = ostart + dstCapacity;
     BYTE* op = ostart;
     size_t const nbSeq = seqStorePtr->sequences - seqStorePtr->sequencesStart;
     BYTE* seqHead;
 
     ZSTD_STATIC_ASSERT(sizeof(entropy->workspace) >= (1<litStart;
         size_t const litSize = seqStorePtr->lit - literals;
         size_t const cSize = ZSTD_compressLiterals(
                 entropy, cParams->strategy, op, dstCapacity, literals, litSize);
         if (ZSTD_isError(cSize))
           return cSize;
+        assert(cSize <= dstCapacity);
         op += cSize;
     }
 
     /* Sequences Header */
-    if ((oend-op) < 3 /*max nbSeq Size*/ + 1 /*seqHead */) return ERROR(dstSize_tooSmall);
-    if (nbSeq < 0x7F) *op++ = (BYTE)nbSeq;
-    else if (nbSeq < LONGNBSEQ) op[0] = (BYTE)((nbSeq>>8) + 0x80), op[1] = (BYTE)nbSeq, op+=2;
-    else op[0]=0xFF, MEM_writeLE16(op+1, (U16)(nbSeq - LONGNBSEQ)), op+=3;
+    if ((oend-op) < 3 /*max nbSeq Size*/ + 1 /*seqHead*/) return ERROR(dstSize_tooSmall);
+    if (nbSeq < 0x7F)
+        *op++ = (BYTE)nbSeq;
+    else if (nbSeq < LONGNBSEQ)
+        op[0] = (BYTE)((nbSeq>>8) + 0x80), op[1] = (BYTE)nbSeq, op+=2;
+    else
+        op[0]=0xFF, MEM_writeLE16(op+1, (U16)(nbSeq - LONGNBSEQ)), op+=3;
     if (nbSeq==0) return op - ostart;
 
     /* seqHead : flags for FSE encoding type */
     seqHead = op++;
 
     /* convert length/distances into codes */
     ZSTD_seqToCodes(seqStorePtr);
-    /* CTable for Literal Lengths */
+    /* build CTable for Literal Lengths */
     {   U32 max = MaxLL;
         size_t const mostFrequent = FSE_countFast_wksp(count, &max, llCodeTable, nbSeq, entropy->workspace);
+        DEBUGLOG(5, "Building LL table");
         LLtype = ZSTD_selectEncodingType(&entropy->litlength_repeatMode, mostFrequent, nbSeq, LL_defaultNormLog, ZSTD_defaultAllowed);
         {   size_t const countSize = ZSTD_buildCTable(op, oend - op, CTable_LitLength, LLFSELog, (symbolEncodingType_e)LLtype,
                     count, max, llCodeTable, nbSeq, LL_defaultNorm, LL_defaultNormLog, MaxLL,
                     entropy->workspace, sizeof(entropy->workspace));
             if (ZSTD_isError(countSize)) return countSize;
             op += countSize;
     }   }
-    /* CTable for Offsets */
+    /* build CTable for Offsets */
     {   U32 max = MaxOff;
         size_t const mostFrequent = FSE_countFast_wksp(count, &max, ofCodeTable, nbSeq, entropy->workspace);
         /* We can only use the basic table if max <= DefaultMaxOff, otherwise the offsets are too large */
-        ZSTD_defaultPolicy_e const defaultPolicy = max <= DefaultMaxOff ? ZSTD_defaultAllowed : ZSTD_defaultDisallowed;
+        ZSTD_defaultPolicy_e const defaultPolicy = (max <= DefaultMaxOff) ? ZSTD_defaultAllowed : ZSTD_defaultDisallowed;
+        DEBUGLOG(5, "Building OF table");
         Offtype = ZSTD_selectEncodingType(&entropy->offcode_repeatMode, mostFrequent, nbSeq, OF_defaultNormLog, defaultPolicy);
         {   size_t const countSize = ZSTD_buildCTable(op, oend - op, CTable_OffsetBits, OffFSELog, (symbolEncodingType_e)Offtype,
                     count, max, ofCodeTable, nbSeq, OF_defaultNorm, OF_defaultNormLog, DefaultMaxOff,
                     entropy->workspace, sizeof(entropy->workspace));
             if (ZSTD_isError(countSize)) return countSize;
             op += countSize;
     }   }
-    /* CTable for MatchLengths */
+    /* build CTable for MatchLengths */
     {   U32 max = MaxML;
         size_t const mostFrequent = FSE_countFast_wksp(count, &max, mlCodeTable, nbSeq, entropy->workspace);
+        DEBUGLOG(5, "Building ML table");
         MLtype = ZSTD_selectEncodingType(&entropy->matchlength_repeatMode, mostFrequent, nbSeq, ML_defaultNormLog, ZSTD_defaultAllowed);
         {   size_t const countSize = ZSTD_buildCTable(op, oend - op, CTable_MatchLength, MLFSELog, (symbolEncodingType_e)MLtype,
                     count, max, mlCodeTable, nbSeq, ML_defaultNorm, ML_defaultNormLog, MaxML,
                     entropy->workspace, sizeof(entropy->workspace));
             if (ZSTD_isError(countSize)) return countSize;
             op += countSize;
     }   }
 
     *seqHead = (BYTE)((LLtype<<6) + (Offtype<<4) + (MLtype<<2));
 
-    {   size_t const streamSize = ZSTD_encodeSequences(op, oend - op,
-                CTable_MatchLength, mlCodeTable,
-                CTable_OffsetBits, ofCodeTable,
-                CTable_LitLength, llCodeTable,
-                sequences, nbSeq, longOffsets);
-        if (ZSTD_isError(streamSize)) return streamSize;
-        op += streamSize;
+    {   size_t const bitstreamSize = ZSTD_encodeSequences(
+                                        op, oend - op,
+                                        CTable_MatchLength, mlCodeTable,
+                                        CTable_OffsetBits, ofCodeTable,
+                                        CTable_LitLength, llCodeTable,
+                                        sequences, nbSeq,
+                                        longOffsets);
+        if (ZSTD_isError(bitstreamSize)) return bitstreamSize;
+        op += bitstreamSize;
     }
 
     return op - ostart;
 }
 
 MEM_STATIC size_t ZSTD_compressSequences(seqStore_t* seqStorePtr,
                               ZSTD_entropyCTables_t* entropy,
                               ZSTD_compressionParameters const* cParams,
                               void* dst, size_t dstCapacity,
                               size_t srcSize)
 {
     size_t const cSize = ZSTD_compressSequences_internal(seqStorePtr, entropy, cParams,
                                                          dst, dstCapacity);
-    size_t const minGain = ZSTD_minGain(srcSize);
-    size_t const maxCSize = srcSize - minGain;
     /* If the srcSize <= dstCapacity, then there is enough space to write a
      * raw uncompressed block. Since we ran out of space, the block must not
      * be compressible, so fall back to a raw uncompressed block.
      */
-    int const uncompressibleError = cSize == ERROR(dstSize_tooSmall) && srcSize <= dstCapacity;
-
+    int const uncompressibleError = (cSize == ERROR(dstSize_tooSmall)) && (srcSize <= dstCapacity);
     if (ZSTD_isError(cSize) && !uncompressibleError)
         return cSize;
+    /* We check that dictionaries have offset codes available for the first
+     * block. After the first block, the offcode table might not have large
+     * enough codes to represent the offsets in the data.
+     */
+    if (entropy->offcode_repeatMode == FSE_repeat_valid)
+        entropy->offcode_repeatMode = FSE_repeat_check;
+
     /* Check compressibility */
-    if (cSize >= maxCSize || uncompressibleError) {
-        entropy->hufCTable_repeatMode = HUF_repeat_none;
-        entropy->offcode_repeatMode = FSE_repeat_none;
-        entropy->matchlength_repeatMode = FSE_repeat_none;
-        entropy->litlength_repeatMode = FSE_repeat_none;
-        return 0;
-    }
+    {   size_t const minGain = ZSTD_minGain(srcSize);  /* note : fixed formula, maybe should depend on compression level, or strategy */
+        size_t const maxCSize = srcSize - minGain;
+        if (cSize >= maxCSize || uncompressibleError) {
+            entropy->hufCTable_repeatMode = HUF_repeat_none;
+            entropy->offcode_repeatMode = FSE_repeat_none;
+            entropy->matchlength_repeatMode = FSE_repeat_none;
+            entropy->litlength_repeatMode = FSE_repeat_none;
+            return 0;  /* block not compressed */
+    }   }
     assert(!ZSTD_isError(cSize));
 
-    /* confirm repcodes */
+    /* block is compressed => confirm repcodes in history */
     { int i; for (i=0; irep[i] = seqStorePtr->repToConfirm[i]; }
     return cSize;
 }
 
 /* ZSTD_selectBlockCompressor() :
  * Not static, but internal use only (used by long distance matcher)
  * assumption : strat is a valid strategy */
 typedef size_t (*ZSTD_blockCompressor) (ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, int extDict)
 {
     static const ZSTD_blockCompressor blockCompressor[2][(unsigned)ZSTD_btultra+1] = {
         { ZSTD_compressBlock_fast  /* default for 0 */,
           ZSTD_compressBlock_fast, ZSTD_compressBlock_doubleFast, ZSTD_compressBlock_greedy,
           ZSTD_compressBlock_lazy, ZSTD_compressBlock_lazy2, ZSTD_compressBlock_btlazy2,
           ZSTD_compressBlock_btopt, ZSTD_compressBlock_btultra },
         { ZSTD_compressBlock_fast_extDict  /* default for 0 */,
           ZSTD_compressBlock_fast_extDict, ZSTD_compressBlock_doubleFast_extDict, ZSTD_compressBlock_greedy_extDict,
           ZSTD_compressBlock_lazy_extDict,ZSTD_compressBlock_lazy2_extDict, ZSTD_compressBlock_btlazy2_extDict,
           ZSTD_compressBlock_btopt_extDict, ZSTD_compressBlock_btultra_extDict }
     };
     ZSTD_STATIC_ASSERT((unsigned)ZSTD_fast == 1);
+
     assert((U32)strat >= (U32)ZSTD_fast);
     assert((U32)strat <= (U32)ZSTD_btultra);
-
     return blockCompressor[extDict!=0][(U32)strat];
 }
 
 static void ZSTD_storeLastLiterals(seqStore_t* seqStorePtr,
                                    const BYTE* anchor, size_t lastLLSize)
 {
     memcpy(seqStorePtr->lit, anchor, lastLLSize);
     seqStorePtr->lit += lastLLSize;
 }
 
-static size_t ZSTD_compressBlock_internal(ZSTD_CCtx* zc, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
+static void ZSTD_resetSeqStore(seqStore_t* ssPtr)
 {
-    const BYTE* const base = zc->base;
-    const BYTE* const istart = (const BYTE*)src;
-    const U32 current = (U32)(istart-base);
-    size_t lastLLSize;
-    const BYTE* anchor;
-    U32 const extDict = zc->lowLimit < zc->dictLimit;
-    const ZSTD_blockCompressor blockCompressor =
-        zc->appliedParams.ldmParams.enableLdm
-            ? (extDict ? ZSTD_compressBlock_ldm_extDict : ZSTD_compressBlock_ldm)
-            : ZSTD_selectBlockCompressor(zc->appliedParams.cParams.strategy, extDict);
+    ssPtr->lit = ssPtr->litStart;
+    ssPtr->sequences = ssPtr->sequencesStart;
+    ssPtr->longLengthID = 0;
+}
 
-    if (srcSize < MIN_CBLOCK_SIZE+ZSTD_blockHeaderSize+1) return 0;   /* don't even attempt compression below a certain srcSize */
+static size_t ZSTD_compressBlock_internal(ZSTD_CCtx* zc, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
+{
+    DEBUGLOG(5, "ZSTD_compressBlock_internal : dstCapacity = %u", (U32)dstCapacity);
+    if (srcSize < MIN_CBLOCK_SIZE+ZSTD_blockHeaderSize+1)
+        return 0;   /* don't even attempt compression below a certain srcSize */
     ZSTD_resetSeqStore(&(zc->seqStore));
-    if (current > zc->nextToUpdate + 384)
-        zc->nextToUpdate = current - MIN(192, (U32)(current - zc->nextToUpdate - 384));   /* limited update after finding a very long match */
 
-    lastLLSize = blockCompressor(zc, src, srcSize);
-
-    /* Last literals */
-    anchor = (const BYTE*)src + srcSize - lastLLSize;
-    ZSTD_storeLastLiterals(&zc->seqStore, anchor, lastLLSize);
-
+    /* limited update after a very long match */
+    {   const BYTE* const base = zc->base;
+        const BYTE* const istart = (const BYTE*)src;
+        const U32 current = (U32)(istart-base);
+        if (current > zc->nextToUpdate + 384)
+            zc->nextToUpdate = current - MIN(192, (U32)(current - zc->nextToUpdate - 384));
+    }
+    /* find and store sequences */
+    {   U32 const extDict = zc->lowLimit < zc->dictLimit;
+        const ZSTD_blockCompressor blockCompressor =
+            zc->appliedParams.ldmParams.enableLdm
+                ? (extDict ? ZSTD_compressBlock_ldm_extDict : ZSTD_compressBlock_ldm)
+                : ZSTD_selectBlockCompressor(zc->appliedParams.cParams.strategy, extDict);
+        size_t const lastLLSize = blockCompressor(zc, src, srcSize);
+        const BYTE* const anchor = (const BYTE*)src + srcSize - lastLLSize;
+        ZSTD_storeLastLiterals(&zc->seqStore, anchor, lastLLSize);
+    }
+    /* encode */
     return ZSTD_compressSequences(&zc->seqStore, zc->entropy, &zc->appliedParams.cParams, dst, dstCapacity, srcSize);
 }
 
 
 /*! ZSTD_compress_frameChunk() :
 *   Compress a chunk of data into one or multiple blocks.
 *   All blocks will be terminated, all input will be consumed.
 *   Function will issue an error if there is not enough `dstCapacity` to hold the compressed content.
 *   Frame is supposed already started (header already produced)
 *   @return : compressed size, or an error code
 */
 static size_t ZSTD_compress_frameChunk (ZSTD_CCtx* cctx,
                                      void* dst, size_t dstCapacity,
                                const void* src, size_t srcSize,
                                      U32 lastFrameChunk)
 {
     size_t blockSize = cctx->blockSize;
     size_t remaining = srcSize;
     const BYTE* ip = (const BYTE*)src;
     BYTE* const ostart = (BYTE*)dst;
     BYTE* op = ostart;
     U32 const maxDist = (U32)1 << cctx->appliedParams.cParams.windowLog;
+    assert(cctx->appliedParams.cParams.windowLog <= 31);
 
+    DEBUGLOG(5, "ZSTD_compress_frameChunk (blockSize=%u)", (U32)blockSize);
     if (cctx->appliedParams.fParams.checksumFlag && srcSize)
         XXH64_update(&cctx->xxhState, src, srcSize);
 
     while (remaining) {
         U32 const lastBlock = lastFrameChunk & (blockSize >= remaining);
-        size_t cSize;
 
         if (dstCapacity < ZSTD_blockHeaderSize + MIN_CBLOCK_SIZE)
             return ERROR(dstSize_tooSmall);   /* not enough space to store compressed block */
         if (remaining < blockSize) blockSize = remaining;
 
         /* preemptive overflow correction:
          * 1. correction is large enough:
          *    lowLimit > (3<<29) ==> current > 3<<29 + 1< (3<<29 + 1< (3<<29 - blockSize) - (1< (3<<29 - blockSize) - (1<<30)             (NOTE: chainLog <= 30)
          *    > 1<<29 - 1<<17
          *
          * 2. (ip+blockSize - cctx->base) doesn't overflow:
          *    In 32 bit mode we limit windowLog to 30 so we don't get
          *    differences larger than 1<<31-1.
          * 3. cctx->lowLimit < 1<<32:
          *    windowLog <= 31 ==> 3<<29 + 1<lowLimit > (3U<<29)) {
             U32 const cycleMask = ((U32)1 << ZSTD_cycleLog(cctx->appliedParams.cParams.chainLog, cctx->appliedParams.cParams.strategy)) - 1;
             U32 const current = (U32)(ip - cctx->base);
             U32 const newCurrent = (current & cycleMask) + ((U32)1 << cctx->appliedParams.cParams.windowLog);
             U32 const correction = current - newCurrent;
             ZSTD_STATIC_ASSERT(ZSTD_CHAINLOG_MAX <= 30);
             ZSTD_STATIC_ASSERT(ZSTD_WINDOWLOG_MAX_32 <= 30);
             ZSTD_STATIC_ASSERT(ZSTD_WINDOWLOG_MAX <= 31);
             assert(current > newCurrent);
             assert(correction > 1<<28); /* Loose bound, should be about 1<<29 */
             ZSTD_reduceIndex(cctx, correction);
             cctx->base += correction;
             cctx->dictBase += correction;
             cctx->lowLimit -= correction;
             cctx->dictLimit -= correction;
             if (cctx->nextToUpdate < correction) cctx->nextToUpdate = 0;
             else cctx->nextToUpdate -= correction;
             DEBUGLOG(4, "Correction of 0x%x bytes to lowLimit=0x%x\n", correction, cctx->lowLimit);
         }
-
+        /* enforce maxDist */
         if ((U32)(ip+blockSize - cctx->base) > cctx->loadedDictEnd + maxDist) {
-            /* enforce maxDist */
             U32 const newLowLimit = (U32)(ip+blockSize - cctx->base) - maxDist;
             if (cctx->lowLimit < newLowLimit) cctx->lowLimit = newLowLimit;
             if (cctx->dictLimit < cctx->lowLimit) cctx->dictLimit = cctx->lowLimit;
         }
 
-        cSize = ZSTD_compressBlock_internal(cctx, op+ZSTD_blockHeaderSize, dstCapacity-ZSTD_blockHeaderSize, ip, blockSize);
-        if (ZSTD_isError(cSize)) return cSize;
+        {   size_t cSize = ZSTD_compressBlock_internal(cctx,
+                                op+ZSTD_blockHeaderSize, dstCapacity-ZSTD_blockHeaderSize,
+                                ip, blockSize);
+            if (ZSTD_isError(cSize)) return cSize;
 
-        if (cSize == 0) {  /* block is not compressible */
-            U32 const cBlockHeader24 = lastBlock + (((U32)bt_raw)<<1) + (U32)(blockSize << 3);
-            if (blockSize + ZSTD_blockHeaderSize > dstCapacity) return ERROR(dstSize_tooSmall);
-            MEM_writeLE32(op, cBlockHeader24);   /* no pb, 4th byte will be overwritten */
-            memcpy(op + ZSTD_blockHeaderSize, ip, blockSize);
-            cSize = ZSTD_blockHeaderSize+blockSize;
-        } else {
-            U32 const cBlockHeader24 = lastBlock + (((U32)bt_compressed)<<1) + (U32)(cSize << 3);
-            MEM_writeLE24(op, cBlockHeader24);
-            cSize += ZSTD_blockHeaderSize;
-        }
+            if (cSize == 0) {  /* block is not compressible */
+                U32 const cBlockHeader24 = lastBlock + (((U32)bt_raw)<<1) + (U32)(blockSize << 3);
+                if (blockSize + ZSTD_blockHeaderSize > dstCapacity) return ERROR(dstSize_tooSmall);
+                MEM_writeLE32(op, cBlockHeader24);   /* 4th byte will be overwritten */
+                memcpy(op + ZSTD_blockHeaderSize, ip, blockSize);
+                cSize = ZSTD_blockHeaderSize + blockSize;
+            } else {
+                U32 const cBlockHeader24 = lastBlock + (((U32)bt_compressed)<<1) + (U32)(cSize << 3);
+                MEM_writeLE24(op, cBlockHeader24);
+                cSize += ZSTD_blockHeaderSize;
+            }
 
-        remaining -= blockSize;
-        dstCapacity -= cSize;
-        ip += blockSize;
-        op += cSize;
-    }
+            ip += blockSize;
+            assert(remaining >= blockSize);
+            remaining -= blockSize;
+            op += cSize;
+            assert(dstCapacity >= cSize);
+            dstCapacity -= cSize;
+            DEBUGLOG(5, "ZSTD_compress_frameChunk: adding a block of size %u",
+                        (U32)cSize);
+    }   }
 
     if (lastFrameChunk && (op>ostart)) cctx->stage = ZSTDcs_ending;
     return op-ostart;
 }
 
 
 static size_t ZSTD_writeFrameHeader(void* dst, size_t dstCapacity,
                                     ZSTD_CCtx_params params, U64 pledgedSrcSize, U32 dictID)
 {   BYTE* const op = (BYTE*)dst;
     U32   const dictIDSizeCodeLength = (dictID>0) + (dictID>=256) + (dictID>=65536);   /* 0-3 */
     U32   const dictIDSizeCode = params.fParams.noDictIDFlag ? 0 : dictIDSizeCodeLength;   /* 0-3 */
     U32   const checksumFlag = params.fParams.checksumFlag>0;
     U32   const windowSize = (U32)1 << params.cParams.windowLog;
     U32   const singleSegment = params.fParams.contentSizeFlag && (windowSize >= pledgedSrcSize);
     BYTE  const windowLogByte = (BYTE)((params.cParams.windowLog - ZSTD_WINDOWLOG_ABSOLUTEMIN) << 3);
     U32   const fcsCode = params.fParams.contentSizeFlag ?
                      (pledgedSrcSize>=256) + (pledgedSrcSize>=65536+256) + (pledgedSrcSize>=0xFFFFFFFFU) : 0;  /* 0-3 */
     BYTE  const frameHeaderDecriptionByte = (BYTE)(dictIDSizeCode + (checksumFlag<<2) + (singleSegment<<5) + (fcsCode<<6) );
     size_t pos=0;
 
     if (dstCapacity < ZSTD_frameHeaderSize_max) return ERROR(dstSize_tooSmall);
     DEBUGLOG(4, "ZSTD_writeFrameHeader : dictIDFlag : %u ; dictID : %u ; dictIDSizeCode : %u",
                 !params.fParams.noDictIDFlag, dictID,  dictIDSizeCode);
 
     if (params.format == ZSTD_f_zstd1) {
-        DEBUGLOG(4, "writing zstd magic number");
         MEM_writeLE32(dst, ZSTD_MAGICNUMBER);
         pos = 4;
     }
     op[pos++] = frameHeaderDecriptionByte;
     if (!singleSegment) op[pos++] = windowLogByte;
     switch(dictIDSizeCode)
     {
         default:  assert(0); /* impossible */
         case 0 : break;
         case 1 : op[pos] = (BYTE)(dictID); pos++; break;
         case 2 : MEM_writeLE16(op+pos, (U16)dictID); pos+=2; break;
         case 3 : MEM_writeLE32(op+pos, dictID); pos+=4; break;
     }
     switch(fcsCode)
     {
         default:  assert(0); /* impossible */
         case 0 : if (singleSegment) op[pos++] = (BYTE)(pledgedSrcSize); break;
         case 1 : MEM_writeLE16(op+pos, (U16)(pledgedSrcSize-256)); pos+=2; break;
         case 2 : MEM_writeLE32(op+pos, (U32)(pledgedSrcSize)); pos+=4; break;
         case 3 : MEM_writeLE64(op+pos, (U64)(pledgedSrcSize)); pos+=8; break;
     }
     return pos;
 }
 
 
 static size_t ZSTD_compressContinue_internal (ZSTD_CCtx* cctx,
                               void* dst, size_t dstCapacity,
                         const void* src, size_t srcSize,
                                U32 frame, U32 lastFrameChunk)
 {
     const BYTE* const ip = (const BYTE*) src;
     size_t fhSize = 0;
 
-    DEBUGLOG(5, "ZSTD_compressContinue_internal");
-    DEBUGLOG(5, "stage: %u", cctx->stage);
+    DEBUGLOG(5, "ZSTD_compressContinue_internal, stage: %u", cctx->stage);
     if (cctx->stage==ZSTDcs_created) return ERROR(stage_wrong);   /* missing init (ZSTD_compressBegin) */
 
     if (frame && (cctx->stage==ZSTDcs_init)) {
         fhSize = ZSTD_writeFrameHeader(dst, dstCapacity, cctx->appliedParams,
                                        cctx->pledgedSrcSizePlusOne-1, cctx->dictID);
         if (ZSTD_isError(fhSize)) return fhSize;
         dstCapacity -= fhSize;
         dst = (char*)dst + fhSize;
         cctx->stage = ZSTDcs_ongoing;
     }
 
+    if (!srcSize) return fhSize;  /* do not generate an empty block if no input */
+
     /* Check if blocks follow each other */
     if (src != cctx->nextSrc) {
         /* not contiguous */
-        ptrdiff_t const delta = cctx->nextSrc - ip;
+        size_t const distanceFromBase = (size_t)(cctx->nextSrc - cctx->base);
         cctx->lowLimit = cctx->dictLimit;
-        cctx->dictLimit = (U32)(cctx->nextSrc - cctx->base);
+        assert(distanceFromBase == (size_t)(U32)distanceFromBase);  /* should never overflow */
+        cctx->dictLimit = (U32)distanceFromBase;
         cctx->dictBase = cctx->base;
-        cctx->base -= delta;
+        cctx->base = ip - distanceFromBase;
         cctx->nextToUpdate = cctx->dictLimit;
         if (cctx->dictLimit - cctx->lowLimit < HASH_READ_SIZE) cctx->lowLimit = cctx->dictLimit;   /* too small extDict */
     }
+    cctx->nextSrc = ip + srcSize;
 
     /* if input and dictionary overlap : reduce dictionary (area presumed modified by input) */
     if ((ip+srcSize > cctx->dictBase + cctx->lowLimit) & (ip < cctx->dictBase + cctx->dictLimit)) {
         ptrdiff_t const highInputIdx = (ip + srcSize) - cctx->dictBase;
         U32 const lowLimitMax = (highInputIdx > (ptrdiff_t)cctx->dictLimit) ? cctx->dictLimit : (U32)highInputIdx;
         cctx->lowLimit = lowLimitMax;
     }
 
-    cctx->nextSrc = ip + srcSize;
-
-    if (srcSize) {
-        size_t const cSize = frame ?
+    DEBUGLOG(5, "ZSTD_compressContinue_internal (blockSize=%u)", (U32)cctx->blockSize);
+    {   size_t const cSize = frame ?
                              ZSTD_compress_frameChunk (cctx, dst, dstCapacity, src, srcSize, lastFrameChunk) :
                              ZSTD_compressBlock_internal (cctx, dst, dstCapacity, src, srcSize);
         if (ZSTD_isError(cSize)) return cSize;
         cctx->consumedSrcSize += srcSize;
         return cSize + fhSize;
-    } else
-        return fhSize;
+    }
 }
 
 size_t ZSTD_compressContinue (ZSTD_CCtx* cctx,
                               void* dst, size_t dstCapacity,
                         const void* src, size_t srcSize)
 {
     return ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 1 /* frame mode */, 0 /* last chunk */);
 }
 
 
 size_t ZSTD_getBlockSize(const ZSTD_CCtx* cctx)
 {
     ZSTD_compressionParameters const cParams =
             ZSTD_getCParamsFromCCtxParams(cctx->appliedParams, 0, 0);
     return MIN (ZSTD_BLOCKSIZE_MAX, (U32)1 << cParams.windowLog);
 }
 
 size_t ZSTD_compressBlock(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
 {
     size_t const blockSizeMax = ZSTD_getBlockSize(cctx);
     if (srcSize > blockSizeMax) return ERROR(srcSize_wrong);
     return ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 0 /* frame mode */, 0 /* last chunk */);
 }
 
 /*! ZSTD_loadDictionaryContent() :
  *  @return : 0, or an error code
  */
 static size_t ZSTD_loadDictionaryContent(ZSTD_CCtx* zc, const void* src, size_t srcSize)
 {
     const BYTE* const ip = (const BYTE*) src;
     const BYTE* const iend = ip + srcSize;
 
     /* input becomes current prefix */
     zc->lowLimit = zc->dictLimit;
     zc->dictLimit = (U32)(zc->nextSrc - zc->base);
     zc->dictBase = zc->base;
-    zc->base += ip - zc->nextSrc;
+    zc->base = ip - zc->dictLimit;
     zc->nextToUpdate = zc->dictLimit;
     zc->loadedDictEnd = zc->appliedParams.forceWindow ? 0 : (U32)(iend - zc->base);
 
     zc->nextSrc = iend;
     if (srcSize <= HASH_READ_SIZE) return 0;
 
     switch(zc->appliedParams.cParams.strategy)
     {
     case ZSTD_fast:
         ZSTD_fillHashTable (zc, iend, zc->appliedParams.cParams.searchLength);
         break;
     case ZSTD_dfast:
         ZSTD_fillDoubleHashTable (zc, iend, zc->appliedParams.cParams.searchLength);
         break;
 
     case ZSTD_greedy:
     case ZSTD_lazy:
     case ZSTD_lazy2:
         if (srcSize >= HASH_READ_SIZE)
             ZSTD_insertAndFindFirstIndex(zc, iend-HASH_READ_SIZE, zc->appliedParams.cParams.searchLength);
         break;
 
     case ZSTD_btlazy2:
     case ZSTD_btopt:
     case ZSTD_btultra:
         if (srcSize >= HASH_READ_SIZE)
             ZSTD_updateTree(zc, iend-HASH_READ_SIZE, iend, (U32)1 << zc->appliedParams.cParams.searchLog, zc->appliedParams.cParams.searchLength);
         break;
 
     default:
         assert(0);  /* not possible : not a valid strategy id */
     }
 
     zc->nextToUpdate = (U32)(iend - zc->base);
     return 0;
 }
 
 
 /* Dictionaries that assign zero probability to symbols that show up causes problems
    when FSE encoding.  Refuse dictionaries that assign zero probability to symbols
    that we may encounter during compression.
    NOTE: This behavior is not standard and could be improved in the future. */
 static size_t ZSTD_checkDictNCount(short* normalizedCounter, unsigned dictMaxSymbolValue, unsigned maxSymbolValue) {
     U32 s;
     if (dictMaxSymbolValue < maxSymbolValue) return ERROR(dictionary_corrupted);
     for (s = 0; s <= maxSymbolValue; ++s) {
         if (normalizedCounter[s] == 0) return ERROR(dictionary_corrupted);
     }
     return 0;
 }
 
 
 /* Dictionary format :
  * See :
  * https://github.com/facebook/zstd/blob/master/doc/zstd_compression_format.md#dictionary-format
  */
 /*! ZSTD_loadZstdDictionary() :
  * @return : 0, or an error code
  *  assumptions : magic number supposed already checked
  *                dictSize supposed > 8
  */
 static size_t ZSTD_loadZstdDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize)
 {
     const BYTE* dictPtr = (const BYTE*)dict;
     const BYTE* const dictEnd = dictPtr + dictSize;
     short offcodeNCount[MaxOff+1];
     unsigned offcodeMaxValue = MaxOff;
 
     ZSTD_STATIC_ASSERT(sizeof(cctx->entropy->workspace) >= (1<dictID = cctx->appliedParams.fParams.noDictIDFlag ? 0 :  MEM_readLE32(dictPtr);
     dictPtr += 4;
 
     {   unsigned maxSymbolValue = 255;
         size_t const hufHeaderSize = HUF_readCTable((HUF_CElt*)cctx->entropy->hufCTable, &maxSymbolValue, dictPtr, dictEnd-dictPtr);
         if (HUF_isError(hufHeaderSize)) return ERROR(dictionary_corrupted);
         if (maxSymbolValue < 255) return ERROR(dictionary_corrupted);
         dictPtr += hufHeaderSize;
     }
 
     {   unsigned offcodeLog;
         size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, dictEnd-dictPtr);
         if (FSE_isError(offcodeHeaderSize)) return ERROR(dictionary_corrupted);
         if (offcodeLog > OffFSELog) return ERROR(dictionary_corrupted);
         /* Defer checking offcodeMaxValue because we need to know the size of the dictionary content */
         CHECK_E( FSE_buildCTable_wksp(cctx->entropy->offcodeCTable, offcodeNCount, offcodeMaxValue, offcodeLog, cctx->entropy->workspace, sizeof(cctx->entropy->workspace)),
                  dictionary_corrupted);
         dictPtr += offcodeHeaderSize;
     }
 
     {   short matchlengthNCount[MaxML+1];
         unsigned matchlengthMaxValue = MaxML, matchlengthLog;
         size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd-dictPtr);
         if (FSE_isError(matchlengthHeaderSize)) return ERROR(dictionary_corrupted);
         if (matchlengthLog > MLFSELog) return ERROR(dictionary_corrupted);
         /* Every match length code must have non-zero probability */
         CHECK_F( ZSTD_checkDictNCount(matchlengthNCount, matchlengthMaxValue, MaxML));
         CHECK_E( FSE_buildCTable_wksp(cctx->entropy->matchlengthCTable, matchlengthNCount, matchlengthMaxValue, matchlengthLog, cctx->entropy->workspace, sizeof(cctx->entropy->workspace)),
                  dictionary_corrupted);
         dictPtr += matchlengthHeaderSize;
     }
 
     {   short litlengthNCount[MaxLL+1];
         unsigned litlengthMaxValue = MaxLL, litlengthLog;
         size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd-dictPtr);
         if (FSE_isError(litlengthHeaderSize)) return ERROR(dictionary_corrupted);
         if (litlengthLog > LLFSELog) return ERROR(dictionary_corrupted);
         /* Every literal length code must have non-zero probability */
         CHECK_F( ZSTD_checkDictNCount(litlengthNCount, litlengthMaxValue, MaxLL));
         CHECK_E( FSE_buildCTable_wksp(cctx->entropy->litlengthCTable, litlengthNCount, litlengthMaxValue, litlengthLog, cctx->entropy->workspace, sizeof(cctx->entropy->workspace)),
                  dictionary_corrupted);
         dictPtr += litlengthHeaderSize;
     }
 
     if (dictPtr+12 > dictEnd) return ERROR(dictionary_corrupted);
     cctx->seqStore.rep[0] = MEM_readLE32(dictPtr+0);
     cctx->seqStore.rep[1] = MEM_readLE32(dictPtr+4);
     cctx->seqStore.rep[2] = MEM_readLE32(dictPtr+8);
     dictPtr += 12;
 
     {   size_t const dictContentSize = (size_t)(dictEnd - dictPtr);
         U32 offcodeMax = MaxOff;
         if (dictContentSize <= ((U32)-1) - 128 KB) {
             U32 const maxOffset = (U32)dictContentSize + 128 KB; /* The maximum offset that must be supported */
             offcodeMax = ZSTD_highbit32(maxOffset); /* Calculate minimum offset code required to represent maxOffset */
         }
         /* All offset values <= dictContentSize + 128 KB must be representable */
         CHECK_F (ZSTD_checkDictNCount(offcodeNCount, offcodeMaxValue, MIN(offcodeMax, MaxOff)));
         /* All repCodes must be <= dictContentSize and != 0*/
         {   U32 u;
             for (u=0; u<3; u++) {
                 if (cctx->seqStore.rep[u] == 0) return ERROR(dictionary_corrupted);
                 if (cctx->seqStore.rep[u] > dictContentSize) return ERROR(dictionary_corrupted);
         }   }
 
         cctx->entropy->hufCTable_repeatMode = HUF_repeat_valid;
         cctx->entropy->offcode_repeatMode = FSE_repeat_valid;
         cctx->entropy->matchlength_repeatMode = FSE_repeat_valid;
         cctx->entropy->litlength_repeatMode = FSE_repeat_valid;
         return ZSTD_loadDictionaryContent(cctx, dictPtr, dictContentSize);
     }
 }
 
 /** ZSTD_compress_insertDictionary() :
 *   @return : 0, or an error code */
 static size_t ZSTD_compress_insertDictionary(ZSTD_CCtx* cctx,
                                        const void* dict, size_t dictSize,
                                              ZSTD_dictMode_e dictMode)
 {
-    DEBUGLOG(5, "ZSTD_compress_insertDictionary");
+    DEBUGLOG(4, "ZSTD_compress_insertDictionary (dictSize=%u)", (U32)dictSize);
     if ((dict==NULL) || (dictSize<=8)) return 0;
 
     /* dict restricted modes */
     if (dictMode==ZSTD_dm_rawContent)
         return ZSTD_loadDictionaryContent(cctx, dict, dictSize);
 
     if (MEM_readLE32(dict) != ZSTD_MAGIC_DICTIONARY) {
         if (dictMode == ZSTD_dm_auto) {
-            DEBUGLOG(5, "raw content dictionary detected");
+            DEBUGLOG(4, "raw content dictionary detected");
             return ZSTD_loadDictionaryContent(cctx, dict, dictSize);
         }
         if (dictMode == ZSTD_dm_fullDict)
             return ERROR(dictionary_wrong);
         assert(0);   /* impossible */
     }
 
     /* dict as full zstd dictionary */
     return ZSTD_loadZstdDictionary(cctx, dict, dictSize);
 }
 
 /*! ZSTD_compressBegin_internal() :
  * @return : 0, or an error code */
-static size_t ZSTD_compressBegin_internal(ZSTD_CCtx* cctx,
+size_t ZSTD_compressBegin_internal(ZSTD_CCtx* cctx,
                              const void* dict, size_t dictSize,
                              ZSTD_dictMode_e dictMode,
                              const ZSTD_CDict* cdict,
-                                   ZSTD_CCtx_params params, U64 pledgedSrcSize,
-                                   ZSTD_buffered_policy_e zbuff)
+                             ZSTD_CCtx_params params, U64 pledgedSrcSize,
+                             ZSTD_buffered_policy_e zbuff)
 {
-    DEBUGLOG(4, "ZSTD_compressBegin_internal");
+    DEBUGLOG(4, "ZSTD_compressBegin_internal: wlog=%u", params.cParams.windowLog);
     /* params are supposed to be fully validated at this point */
     assert(!ZSTD_isError(ZSTD_checkCParams(params.cParams)));
     assert(!((dict) && (cdict)));  /* either dict or cdict, not both */
 
     if (cdict && cdict->dictContentSize>0) {
+        cctx->requestedParams = params;
         return ZSTD_copyCCtx_internal(cctx, cdict->refContext,
-                                      params.fParams, pledgedSrcSize,
+                                      params.cParams.windowLog, params.fParams, pledgedSrcSize,
                                       zbuff);
     }
 
     CHECK_F( ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize,
                                      ZSTDcrp_continue, zbuff) );
     return ZSTD_compress_insertDictionary(cctx, dict, dictSize, dictMode);
 }
 
-size_t ZSTD_compressBegin_advanced_internal(
-                                    ZSTD_CCtx* cctx,
+size_t ZSTD_compressBegin_advanced_internal(ZSTD_CCtx* cctx,
                                     const void* dict, size_t dictSize,
                                     ZSTD_dictMode_e dictMode,
+                                    const ZSTD_CDict* cdict,
                                     ZSTD_CCtx_params params,
                                     unsigned long long pledgedSrcSize)
 {
+    DEBUGLOG(4, "ZSTD_compressBegin_advanced_internal: wlog=%u", params.cParams.windowLog);
     /* compression parameters verification and optimization */
     CHECK_F( ZSTD_checkCParams(params.cParams) );
-    return ZSTD_compressBegin_internal(cctx, dict, dictSize, dictMode, NULL,
+    return ZSTD_compressBegin_internal(cctx,
+                                       dict, dictSize, dictMode,
+                                       cdict,
                                        params, pledgedSrcSize,
                                        ZSTDb_not_buffered);
 }
 
 /*! ZSTD_compressBegin_advanced() :
 *   @return : 0, or an error code */
 size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx,
                              const void* dict, size_t dictSize,
                                    ZSTD_parameters params, unsigned long long pledgedSrcSize)
 {
     ZSTD_CCtx_params const cctxParams =
             ZSTD_assignParamsToCCtxParams(cctx->requestedParams, params);
-    return ZSTD_compressBegin_advanced_internal(cctx, dict, dictSize, ZSTD_dm_auto,
-                                                cctxParams,
-                                                pledgedSrcSize);
+    return ZSTD_compressBegin_advanced_internal(cctx,
+                                            dict, dictSize, ZSTD_dm_auto,
+                                            NULL /*cdict*/,
+                                            cctxParams, pledgedSrcSize);
 }
 
 size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel)
 {
     ZSTD_parameters const params = ZSTD_getParams(compressionLevel, 0, dictSize);
     ZSTD_CCtx_params const cctxParams =
             ZSTD_assignParamsToCCtxParams(cctx->requestedParams, params);
+    DEBUGLOG(4, "ZSTD_compressBegin_usingDict");
     return ZSTD_compressBegin_internal(cctx, dict, dictSize, ZSTD_dm_auto, NULL,
-                                       cctxParams, 0, ZSTDb_not_buffered);
+                                       cctxParams, ZSTD_CONTENTSIZE_UNKNOWN, ZSTDb_not_buffered);
 }
 
 size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel)
 {
     return ZSTD_compressBegin_usingDict(cctx, NULL, 0, compressionLevel);
 }
 
 
 /*! ZSTD_writeEpilogue() :
 *   Ends a frame.
 *   @return : nb of bytes written into dst (or an error code) */
 static size_t ZSTD_writeEpilogue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity)
 {
     BYTE* const ostart = (BYTE*)dst;
     BYTE* op = ostart;
     size_t fhSize = 0;
 
     DEBUGLOG(5, "ZSTD_writeEpilogue");
     if (cctx->stage == ZSTDcs_created) return ERROR(stage_wrong);  /* init missing */
 
     /* special case : empty frame */
     if (cctx->stage == ZSTDcs_init) {
         fhSize = ZSTD_writeFrameHeader(dst, dstCapacity, cctx->appliedParams, 0, 0);
         if (ZSTD_isError(fhSize)) return fhSize;
         dstCapacity -= fhSize;
         op += fhSize;
         cctx->stage = ZSTDcs_ongoing;
     }
 
     if (cctx->stage != ZSTDcs_ending) {
         /* write one last empty block, make it the "last" block */
         U32 const cBlockHeader24 = 1 /* last block */ + (((U32)bt_raw)<<1) + 0;
         if (dstCapacity<4) return ERROR(dstSize_tooSmall);
         MEM_writeLE32(op, cBlockHeader24);
         op += ZSTD_blockHeaderSize;
         dstCapacity -= ZSTD_blockHeaderSize;
     }
 
     if (cctx->appliedParams.fParams.checksumFlag) {
         U32 const checksum = (U32) XXH64_digest(&cctx->xxhState);
         if (dstCapacity<4) return ERROR(dstSize_tooSmall);
         MEM_writeLE32(op, checksum);
         op += 4;
     }
 
     cctx->stage = ZSTDcs_created;  /* return to "created but no init" status */
     return op-ostart;
 }
 
 
 size_t ZSTD_compressEnd (ZSTD_CCtx* cctx,
                          void* dst, size_t dstCapacity,
                    const void* src, size_t srcSize)
 {
     size_t endResult;
     size_t const cSize = ZSTD_compressContinue_internal(cctx,
                                 dst, dstCapacity, src, srcSize,
                                 1 /* frame mode */, 1 /* last chunk */);
     if (ZSTD_isError(cSize)) return cSize;
     endResult = ZSTD_writeEpilogue(cctx, (char*)dst + cSize, dstCapacity-cSize);
     if (ZSTD_isError(endResult)) return endResult;
     if (cctx->appliedParams.fParams.contentSizeFlag) {  /* control src size */
         DEBUGLOG(4, "end of frame : controlling src size");
         if (cctx->pledgedSrcSizePlusOne != cctx->consumedSrcSize+1) {
             DEBUGLOG(4, "error : pledgedSrcSize = %u, while realSrcSize = %u",
                 (U32)cctx->pledgedSrcSizePlusOne-1, (U32)cctx->consumedSrcSize);
             return ERROR(srcSize_wrong);
     }   }
     return cSize + endResult;
 }
 
 
 static size_t ZSTD_compress_internal (ZSTD_CCtx* cctx,
                                void* dst, size_t dstCapacity,
                          const void* src, size_t srcSize,
                          const void* dict,size_t dictSize,
                                ZSTD_parameters params)
 {
     ZSTD_CCtx_params const cctxParams =
             ZSTD_assignParamsToCCtxParams(cctx->requestedParams, params);
+    DEBUGLOG(4, "ZSTD_compress_internal");
     return ZSTD_compress_advanced_internal(cctx,
                                           dst, dstCapacity,
                                           src, srcSize,
                                           dict, dictSize,
                                           cctxParams);
 }
 
 size_t ZSTD_compress_advanced (ZSTD_CCtx* ctx,
                                void* dst, size_t dstCapacity,
                          const void* src, size_t srcSize,
                          const void* dict,size_t dictSize,
                                ZSTD_parameters params)
 {
+    DEBUGLOG(4, "ZSTD_compress_advanced");
     CHECK_F(ZSTD_checkCParams(params.cParams));
     return ZSTD_compress_internal(ctx, dst, dstCapacity, src, srcSize, dict, dictSize, params);
 }
 
 /* Internal */
 size_t ZSTD_compress_advanced_internal(
         ZSTD_CCtx* cctx,
         void* dst, size_t dstCapacity,
         const void* src, size_t srcSize,
         const void* dict,size_t dictSize,
         ZSTD_CCtx_params params)
 {
+    DEBUGLOG(4, "ZSTD_compress_advanced_internal");
     CHECK_F( ZSTD_compressBegin_internal(cctx, dict, dictSize, ZSTD_dm_auto, NULL,
                                          params, srcSize, ZSTDb_not_buffered) );
     return ZSTD_compressEnd(cctx, dst, dstCapacity, src, srcSize);
 }
 
 size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize,
                                const void* dict, size_t dictSize, int compressionLevel)
 {
-    ZSTD_parameters params = ZSTD_getParams(compressionLevel, srcSize, dict ? dictSize : 0);
+    ZSTD_parameters params = ZSTD_getParams(compressionLevel, srcSize ? srcSize : 1, dict ? dictSize : 0);
     params.fParams.contentSizeFlag = 1;
+    DEBUGLOG(4, "ZSTD_compress_usingDict (level=%i, srcSize=%u, dictSize=%u)",
+                compressionLevel, (U32)srcSize, (U32)dictSize);
     return ZSTD_compress_internal(ctx, dst, dstCapacity, src, srcSize, dict, dictSize, params);
 }
 
 size_t ZSTD_compressCCtx (ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel)
 {
     return ZSTD_compress_usingDict(ctx, dst, dstCapacity, src, srcSize, NULL, 0, compressionLevel);
 }
 
 size_t ZSTD_compress(void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel)
 {
     size_t result;
     ZSTD_CCtx ctxBody;
     memset(&ctxBody, 0, sizeof(ctxBody));
     ctxBody.customMem = ZSTD_defaultCMem;
     result = ZSTD_compressCCtx(&ctxBody, dst, dstCapacity, src, srcSize, compressionLevel);
     ZSTD_free(ctxBody.workSpace, ZSTD_defaultCMem);  /* can't free ctxBody itself, as it's on stack; free only heap content */
     return result;
 }
 
 
 /* =====  Dictionary API  ===== */
 
 /*! ZSTD_estimateCDictSize_advanced() :
  *  Estimate amount of memory that will be needed to create a dictionary with following arguments */
 size_t ZSTD_estimateCDictSize_advanced(
         size_t dictSize, ZSTD_compressionParameters cParams,
         ZSTD_dictLoadMethod_e dictLoadMethod)
 {
     DEBUGLOG(5, "sizeof(ZSTD_CDict) : %u", (U32)sizeof(ZSTD_CDict));
     DEBUGLOG(5, "CCtx estimate : %u",
              (U32)ZSTD_estimateCCtxSize_usingCParams(cParams));
     return sizeof(ZSTD_CDict) + ZSTD_estimateCCtxSize_usingCParams(cParams)
            + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
 }
 
 size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel)
 {
     ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, 0, dictSize);
     return ZSTD_estimateCDictSize_advanced(dictSize, cParams, ZSTD_dlm_byCopy);
 }
 
 size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict)
 {
     if (cdict==NULL) return 0;   /* support sizeof on NULL */
     DEBUGLOG(5, "sizeof(*cdict) : %u", (U32)sizeof(*cdict));
     DEBUGLOG(5, "ZSTD_sizeof_CCtx : %u", (U32)ZSTD_sizeof_CCtx(cdict->refContext));
     return ZSTD_sizeof_CCtx(cdict->refContext) + (cdict->dictBuffer ? cdict->dictContentSize : 0) + sizeof(*cdict);
 }
 
 static size_t ZSTD_initCDict_internal(
                     ZSTD_CDict* cdict,
               const void* dictBuffer, size_t dictSize,
                     ZSTD_dictLoadMethod_e dictLoadMethod,
                     ZSTD_dictMode_e dictMode,
                     ZSTD_compressionParameters cParams)
 {
-    DEBUGLOG(5, "ZSTD_initCDict_internal, mode %u", (U32)dictMode);
+    DEBUGLOG(3, "ZSTD_initCDict_internal, mode %u", (U32)dictMode);
     if ((dictLoadMethod == ZSTD_dlm_byRef) || (!dictBuffer) || (!dictSize)) {
         cdict->dictBuffer = NULL;
         cdict->dictContent = dictBuffer;
     } else {
         void* const internalBuffer = ZSTD_malloc(dictSize, cdict->refContext->customMem);
         cdict->dictBuffer = internalBuffer;
         cdict->dictContent = internalBuffer;
         if (!internalBuffer) return ERROR(memory_allocation);
         memcpy(internalBuffer, dictBuffer, dictSize);
     }
     cdict->dictContentSize = dictSize;
 
     {   ZSTD_CCtx_params cctxParams = cdict->refContext->requestedParams;
         cctxParams.cParams = cParams;
         CHECK_F( ZSTD_compressBegin_internal(cdict->refContext,
                                         cdict->dictContent, dictSize, dictMode,
                                         NULL,
                                         cctxParams, ZSTD_CONTENTSIZE_UNKNOWN,
                                         ZSTDb_not_buffered) );
     }
 
     return 0;
 }
 
 ZSTD_CDict* ZSTD_createCDict_advanced(const void* dictBuffer, size_t dictSize,
                                       ZSTD_dictLoadMethod_e dictLoadMethod,
                                       ZSTD_dictMode_e dictMode,
                                       ZSTD_compressionParameters cParams, ZSTD_customMem customMem)
 {
-    DEBUGLOG(5, "ZSTD_createCDict_advanced, mode %u", (U32)dictMode);
+    DEBUGLOG(3, "ZSTD_createCDict_advanced, mode %u", (U32)dictMode);
     if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
 
     {   ZSTD_CDict* const cdict = (ZSTD_CDict*)ZSTD_malloc(sizeof(ZSTD_CDict), customMem);
         ZSTD_CCtx* const cctx = ZSTD_createCCtx_advanced(customMem);
 
         if (!cdict || !cctx) {
             ZSTD_free(cdict, customMem);
             ZSTD_freeCCtx(cctx);
             return NULL;
         }
         cdict->refContext = cctx;
         if (ZSTD_isError( ZSTD_initCDict_internal(cdict,
                                         dictBuffer, dictSize,
                                         dictLoadMethod, dictMode,
                                         cParams) )) {
             ZSTD_freeCDict(cdict);
             return NULL;
         }
 
         return cdict;
     }
 }
 
 ZSTD_CDict* ZSTD_createCDict(const void* dict, size_t dictSize, int compressionLevel)
 {
     ZSTD_compressionParameters cParams = ZSTD_getCParams(compressionLevel, 0, dictSize);
     return ZSTD_createCDict_advanced(dict, dictSize,
                                      ZSTD_dlm_byCopy, ZSTD_dm_auto,
                                      cParams, ZSTD_defaultCMem);
 }
 
 ZSTD_CDict* ZSTD_createCDict_byReference(const void* dict, size_t dictSize, int compressionLevel)
 {
     ZSTD_compressionParameters cParams = ZSTD_getCParams(compressionLevel, 0, dictSize);
     return ZSTD_createCDict_advanced(dict, dictSize,
                                      ZSTD_dlm_byRef, ZSTD_dm_auto,
                                      cParams, ZSTD_defaultCMem);
 }
 
 size_t ZSTD_freeCDict(ZSTD_CDict* cdict)
 {
     if (cdict==NULL) return 0;   /* support free on NULL */
     {   ZSTD_customMem const cMem = cdict->refContext->customMem;
         ZSTD_freeCCtx(cdict->refContext);
         ZSTD_free(cdict->dictBuffer, cMem);
         ZSTD_free(cdict, cMem);
         return 0;
     }
 }
 
 /*! ZSTD_initStaticCDict_advanced() :
  *  Generate a digested dictionary in provided memory area.
  *  workspace: The memory area to emplace the dictionary into.
  *             Provided pointer must 8-bytes aligned.
  *             It must outlive dictionary usage.
  *  workspaceSize: Use ZSTD_estimateCDictSize()
  *                 to determine how large workspace must be.
  *  cParams : use ZSTD_getCParams() to transform a compression level
  *            into its relevants cParams.
  * @return : pointer to ZSTD_CDict*, or NULL if error (size too small)
  *  Note : there is no corresponding "free" function.
  *         Since workspace was allocated externally, it must be freed externally.
  */
 ZSTD_CDict* ZSTD_initStaticCDict(void* workspace, size_t workspaceSize,
                            const void* dict, size_t dictSize,
                                  ZSTD_dictLoadMethod_e dictLoadMethod,
                                  ZSTD_dictMode_e dictMode,
                                  ZSTD_compressionParameters cParams)
 {
     size_t const cctxSize = ZSTD_estimateCCtxSize_usingCParams(cParams);
     size_t const neededSize = sizeof(ZSTD_CDict) + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize)
                             + cctxSize;
     ZSTD_CDict* const cdict = (ZSTD_CDict*) workspace;
     void* ptr;
-    DEBUGLOG(5, "(size_t)workspace & 7 : %u", (U32)(size_t)workspace & 7);
+    DEBUGLOG(4, "(size_t)workspace & 7 : %u", (U32)(size_t)workspace & 7);
     if ((size_t)workspace & 7) return NULL;  /* 8-aligned */
-    DEBUGLOG(5, "(workspaceSize < neededSize) : (%u < %u) => %u",
+    DEBUGLOG(4, "(workspaceSize < neededSize) : (%u < %u) => %u",
         (U32)workspaceSize, (U32)neededSize, (U32)(workspaceSize < neededSize));
     if (workspaceSize < neededSize) return NULL;
 
     if (dictLoadMethod == ZSTD_dlm_byCopy) {
         memcpy(cdict+1, dict, dictSize);
         dict = cdict+1;
         ptr = (char*)workspace + sizeof(ZSTD_CDict) + dictSize;
     } else {
         ptr = cdict+1;
     }
     cdict->refContext = ZSTD_initStaticCCtx(ptr, cctxSize);
 
     if (ZSTD_isError( ZSTD_initCDict_internal(cdict,
                                               dict, dictSize,
                                               ZSTD_dlm_byRef, dictMode,
                                               cParams) ))
         return NULL;
 
     return cdict;
 }
 
 ZSTD_compressionParameters ZSTD_getCParamsFromCDict(const ZSTD_CDict* cdict) {
     return cdict->refContext->appliedParams.cParams;
 }
 
 /* ZSTD_compressBegin_usingCDict_advanced() :
  * cdict must be != NULL */
 size_t ZSTD_compressBegin_usingCDict_advanced(
     ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict,
     ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize)
 {
+    DEBUGLOG(4, "ZSTD_compressBegin_usingCDict_advanced");
     if (cdict==NULL) return ERROR(dictionary_wrong);
     {   ZSTD_CCtx_params params = cctx->requestedParams;
         params.cParams = ZSTD_getCParamsFromCDict(cdict);
         params.fParams = fParams;
-        DEBUGLOG(5, "ZSTD_compressBegin_usingCDict_advanced");
         return ZSTD_compressBegin_internal(cctx,
                                            NULL, 0, ZSTD_dm_auto,
                                            cdict,
                                            params, pledgedSrcSize,
                                            ZSTDb_not_buffered);
     }
 }
 
 /* ZSTD_compressBegin_usingCDict() :
  * pledgedSrcSize=0 means "unknown"
  * if pledgedSrcSize>0, it will enable contentSizeFlag */
 size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict)
 {
     ZSTD_frameParameters const fParams = { 0 /*content*/, 0 /*checksum*/, 0 /*noDictID*/ };
-    DEBUGLOG(5, "ZSTD_compressBegin_usingCDict : dictIDFlag == %u", !fParams.noDictIDFlag);
+    DEBUGLOG(4, "ZSTD_compressBegin_usingCDict : dictIDFlag == %u", !fParams.noDictIDFlag);
     return ZSTD_compressBegin_usingCDict_advanced(cctx, cdict, fParams, 0);
 }
 
 size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx,
                                 void* dst, size_t dstCapacity,
                                 const void* src, size_t srcSize,
                                 const ZSTD_CDict* cdict, ZSTD_frameParameters fParams)
 {
     CHECK_F (ZSTD_compressBegin_usingCDict_advanced(cctx, cdict, fParams, srcSize));   /* will check if cdict != NULL */
     return ZSTD_compressEnd(cctx, dst, dstCapacity, src, srcSize);
 }
 
 /*! ZSTD_compress_usingCDict() :
  *  Compression using a digested Dictionary.
  *  Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times.
  *  Note that compression parameters are decided at CDict creation time
  *  while frame parameters are hardcoded */
 size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
                                 void* dst, size_t dstCapacity,
                                 const void* src, size_t srcSize,
                                 const ZSTD_CDict* cdict)
 {
     ZSTD_frameParameters const fParams = { 1 /*content*/, 0 /*checksum*/, 0 /*noDictID*/ };
     return ZSTD_compress_usingCDict_advanced(cctx, dst, dstCapacity, src, srcSize, cdict, fParams);
 }
 
 
 
 /* ******************************************************************
 *  Streaming
 ********************************************************************/
 
 ZSTD_CStream* ZSTD_createCStream(void)
 {
+    DEBUGLOG(3, "ZSTD_createCStream");
     return ZSTD_createCStream_advanced(ZSTD_defaultCMem);
 }
 
 ZSTD_CStream* ZSTD_initStaticCStream(void *workspace, size_t workspaceSize)
 {
     return ZSTD_initStaticCCtx(workspace, workspaceSize);
 }
 
 ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem)
 {   /* CStream and CCtx are now same object */
     return ZSTD_createCCtx_advanced(customMem);
 }
 
 size_t ZSTD_freeCStream(ZSTD_CStream* zcs)
 {
     return ZSTD_freeCCtx(zcs);   /* same object */
 }
 
 
 
 /*======   Initialization   ======*/
 
 size_t ZSTD_CStreamInSize(void)  { return ZSTD_BLOCKSIZE_MAX; }
 
 size_t ZSTD_CStreamOutSize(void)
 {
     return ZSTD_compressBound(ZSTD_BLOCKSIZE_MAX) + ZSTD_blockHeaderSize + 4 /* 32-bits hash */ ;
 }
 
 static size_t ZSTD_resetCStream_internal(ZSTD_CStream* zcs,
-                    const void* dict, size_t dictSize, ZSTD_dictMode_e dictMode,
-                    const ZSTD_CDict* cdict,
-                    const ZSTD_CCtx_params params, unsigned long long pledgedSrcSize)
+                    const void* const dict, size_t const dictSize, ZSTD_dictMode_e const dictMode,
+                    const ZSTD_CDict* const cdict,
+                    ZSTD_CCtx_params const params, unsigned long long const pledgedSrcSize)
 {
     DEBUGLOG(4, "ZSTD_resetCStream_internal");
     /* params are supposed to be fully validated at this point */
     assert(!ZSTD_isError(ZSTD_checkCParams(params.cParams)));
     assert(!((dict) && (cdict)));  /* either dict or cdict, not both */
 
     CHECK_F( ZSTD_compressBegin_internal(zcs,
-                                        dict, dictSize, dictMode,
-                                        cdict,
-                                        params, pledgedSrcSize,
-                                        ZSTDb_buffered) );
+                                         dict, dictSize, dictMode,
+                                         cdict,
+                                         params, pledgedSrcSize,
+                                         ZSTDb_buffered) );
 
     zcs->inToCompress = 0;
     zcs->inBuffPos = 0;
-    zcs->inBuffTarget = zcs->blockSize;
+    zcs->inBuffTarget = zcs->blockSize
+                      + (zcs->blockSize == pledgedSrcSize);   /* for small input: avoid automatic flush on reaching end of block, since it would require to add a 3-bytes null block to end frame */
     zcs->outBuffContentSize = zcs->outBuffFlushedSize = 0;
     zcs->streamStage = zcss_load;
     zcs->frameEnded = 0;
     return 0;   /* ready to go */
 }
 
+/* ZSTD_resetCStream():
+ * pledgedSrcSize == 0 means "unknown" */
 size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize)
 {
     ZSTD_CCtx_params params = zcs->requestedParams;
-    params.fParams.contentSizeFlag = (pledgedSrcSize > 0);
+    DEBUGLOG(4, "ZSTD_resetCStream: pledgedSrcSize = %u", (U32)pledgedSrcSize);
+    if (pledgedSrcSize==0) pledgedSrcSize = ZSTD_CONTENTSIZE_UNKNOWN;
+    params.fParams.contentSizeFlag = 1;
     params.cParams = ZSTD_getCParamsFromCCtxParams(params, pledgedSrcSize, 0);
-    DEBUGLOG(4, "ZSTD_resetCStream");
     return ZSTD_resetCStream_internal(zcs, NULL, 0, ZSTD_dm_auto, zcs->cdict, params, pledgedSrcSize);
 }
 
 /*! ZSTD_initCStream_internal() :
- *  Note : not static, but hidden (not exposed). Used by zstdmt_compress.c
+ *  Note : for lib/compress only. Used by zstdmt_compress.c.
  *  Assumption 1 : params are valid
  *  Assumption 2 : either dict, or cdict, is defined, not both */
 size_t ZSTD_initCStream_internal(ZSTD_CStream* zcs,
                     const void* dict, size_t dictSize, const ZSTD_CDict* cdict,
                     ZSTD_CCtx_params params, unsigned long long pledgedSrcSize)
 {
     DEBUGLOG(4, "ZSTD_initCStream_internal");
     assert(!ZSTD_isError(ZSTD_checkCParams(params.cParams)));
     assert(!((dict) && (cdict)));  /* either dict or cdict, not both */
 
     if (dict && dictSize >= 8) {
-        DEBUGLOG(5, "loading dictionary of size %u", (U32)dictSize);
+        DEBUGLOG(4, "loading dictionary of size %u", (U32)dictSize);
         if (zcs->staticSize) {   /* static CCtx : never uses malloc */
             /* incompatible with internal cdict creation */
             return ERROR(memory_allocation);
         }
         ZSTD_freeCDict(zcs->cdictLocal);
         zcs->cdictLocal = ZSTD_createCDict_advanced(dict, dictSize,
                                             ZSTD_dlm_byCopy, ZSTD_dm_auto,
                                             params.cParams, zcs->customMem);
         zcs->cdict = zcs->cdictLocal;
         if (zcs->cdictLocal == NULL) return ERROR(memory_allocation);
     } else {
         if (cdict) {
-            params.cParams = ZSTD_getCParamsFromCDict(cdict);  /* cParams are enforced from cdict */
+            params.cParams = ZSTD_getCParamsFromCDict(cdict);  /* cParams are enforced from cdict; it includes windowLog */
         }
         ZSTD_freeCDict(zcs->cdictLocal);
         zcs->cdictLocal = NULL;
         zcs->cdict = cdict;
     }
 
-    params.compressionLevel = ZSTD_CLEVEL_CUSTOM;
+    params.compressionLevel = ZSTD_CLEVEL_CUSTOM; /* enforce usage of cParams, instead of a dynamic derivation from cLevel (but does that happen ?) */
     zcs->requestedParams = params;
 
     return ZSTD_resetCStream_internal(zcs, NULL, 0, ZSTD_dm_auto, zcs->cdict, params, pledgedSrcSize);
 }
 
 /* ZSTD_initCStream_usingCDict_advanced() :
  * same as ZSTD_initCStream_usingCDict(), with control over frame parameters */
 size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs,
                                             const ZSTD_CDict* cdict,
                                             ZSTD_frameParameters fParams,
                                             unsigned long long pledgedSrcSize)
-{   /* cannot handle NULL cdict (does not know what to do) */
-    if (!cdict) return ERROR(dictionary_wrong);
+{
+    DEBUGLOG(4, "ZSTD_initCStream_usingCDict_advanced");
+    if (!cdict) return ERROR(dictionary_wrong); /* cannot handle NULL cdict (does not know what to do) */
     {   ZSTD_CCtx_params params = zcs->requestedParams;
         params.cParams = ZSTD_getCParamsFromCDict(cdict);
         params.fParams = fParams;
         return ZSTD_initCStream_internal(zcs,
                                 NULL, 0, cdict,
                                 params, pledgedSrcSize);
     }
 }
 
 /* note : cdict must outlive compression session */
 size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict)
 {
-    ZSTD_frameParameters const fParams = { 0 /* contentSize */, 0 /* checksum */, 0 /* hideDictID */ };
-    return ZSTD_initCStream_usingCDict_advanced(zcs, cdict, fParams, 0);  /* note : will check that cdict != NULL */
+    ZSTD_frameParameters const fParams = { 0 /* contentSizeFlag */, 0 /* checksum */, 0 /* hideDictID */ };
+    DEBUGLOG(4, "ZSTD_initCStream_usingCDict");
+    return ZSTD_initCStream_usingCDict_advanced(zcs, cdict, fParams, ZSTD_CONTENTSIZE_UNKNOWN);  /* note : will check that cdict != NULL */
 }
 
+/* ZSTD_initCStream_advanced() :
+ * pledgedSrcSize must be correct.
+ * if srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN.
+ * dict is loaded with default parameters ZSTD_dm_auto and ZSTD_dlm_byCopy. */
 size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
                                  const void* dict, size_t dictSize,
                                  ZSTD_parameters params, unsigned long long pledgedSrcSize)
 {
-    ZSTD_CCtx_params const cctxParams =
-            ZSTD_assignParamsToCCtxParams(zcs->requestedParams, params);
+    ZSTD_CCtx_params const cctxParams = ZSTD_assignParamsToCCtxParams(zcs->requestedParams, params);
+    DEBUGLOG(4, "ZSTD_initCStream_advanced: pledgedSrcSize=%u, flag=%u",
+                (U32)pledgedSrcSize, params.fParams.contentSizeFlag);
     CHECK_F( ZSTD_checkCParams(params.cParams) );
-    return ZSTD_initCStream_internal(zcs, dict, dictSize, NULL, cctxParams, pledgedSrcSize);
+    if ((pledgedSrcSize==0) && (params.fParams.contentSizeFlag==0)) pledgedSrcSize = ZSTD_CONTENTSIZE_UNKNOWN;  /* for compatibility with older programs relying on this behavior. Users should now specify ZSTD_CONTENTSIZE_UNKNOWN. This line will be removed in the future. */
+    return ZSTD_initCStream_internal(zcs, dict, dictSize, NULL /*cdict*/, cctxParams, pledgedSrcSize);
 }
 
 size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel)
 {
     ZSTD_parameters const params = ZSTD_getParams(compressionLevel, 0, dictSize);
     ZSTD_CCtx_params const cctxParams =
             ZSTD_assignParamsToCCtxParams(zcs->requestedParams, params);
-    return ZSTD_initCStream_internal(zcs, dict, dictSize, NULL, cctxParams, 0);
+    return ZSTD_initCStream_internal(zcs, dict, dictSize, NULL, cctxParams, ZSTD_CONTENTSIZE_UNKNOWN);
 }
 
-size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize)
+size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pss)
 {
-    ZSTD_CCtx_params cctxParams;
+    U64 const pledgedSrcSize = (pss==0) ? ZSTD_CONTENTSIZE_UNKNOWN : pss;  /* temporary : 0 interpreted as "unknown" during transition period. Users willing to specify "unknown" **must** use ZSTD_CONTENTSIZE_UNKNOWN. `0` will be interpreted as "empty" in the future */
     ZSTD_parameters const params = ZSTD_getParams(compressionLevel, pledgedSrcSize, 0);
-    cctxParams = ZSTD_assignParamsToCCtxParams(zcs->requestedParams, params);
-    cctxParams.fParams.contentSizeFlag = (pledgedSrcSize>0);
+    ZSTD_CCtx_params const cctxParams = ZSTD_assignParamsToCCtxParams(zcs->requestedParams, params);
     return ZSTD_initCStream_internal(zcs, NULL, 0, NULL, cctxParams, pledgedSrcSize);
 }
 
 size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel)
 {
-    return ZSTD_initCStream_srcSize(zcs, compressionLevel, 0);
+    DEBUGLOG(4, "ZSTD_initCStream");
+    return ZSTD_initCStream_srcSize(zcs, compressionLevel, ZSTD_CONTENTSIZE_UNKNOWN);
 }
 
 /*======   Compression   ======*/
 
 MEM_STATIC size_t ZSTD_limitCopy(void* dst, size_t dstCapacity,
                            const void* src, size_t srcSize)
 {
     size_t const length = MIN(dstCapacity, srcSize);
     if (length) memcpy(dst, src, length);
     return length;
 }
 
 /** ZSTD_compressStream_generic():
  *  internal function for all *compressStream*() variants and *compress_generic()
  *  non-static, because can be called from zstdmt.c
  * @return : hint size for next input */
 size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
                                    ZSTD_outBuffer* output,
                                    ZSTD_inBuffer* input,
                                    ZSTD_EndDirective const flushMode)
 {
     const char* const istart = (const char*)input->src;
     const char* const iend = istart + input->size;
     const char* ip = istart + input->pos;
     char* const ostart = (char*)output->dst;
     char* const oend = ostart + output->size;
     char* op = ostart + output->pos;
     U32 someMoreWork = 1;
 
     /* check expectations */
     DEBUGLOG(5, "ZSTD_compressStream_generic, flush=%u", (U32)flushMode);
     assert(zcs->inBuff != NULL);
-    assert(zcs->inBuffSize>0);
-    assert(zcs->outBuff!= NULL);
-    assert(zcs->outBuffSize>0);
+    assert(zcs->inBuffSize > 0);
+    assert(zcs->outBuff !=  NULL);
+    assert(zcs->outBuffSize > 0);
     assert(output->pos <= output->size);
     assert(input->pos <= input->size);
 
     while (someMoreWork) {
         switch(zcs->streamStage)
         {
         case zcss_init:
             /* call ZSTD_initCStream() first ! */
             return ERROR(init_missing);
 
         case zcss_load:
             if ( (flushMode == ZSTD_e_end)
               && ((size_t)(oend-op) >= ZSTD_compressBound(iend-ip))  /* enough dstCapacity */
               && (zcs->inBuffPos == 0) ) {
                 /* shortcut to compression pass directly into output buffer */
                 size_t const cSize = ZSTD_compressEnd(zcs,
                                                 op, oend-op, ip, iend-ip);
                 DEBUGLOG(4, "ZSTD_compressEnd : %u", (U32)cSize);
                 if (ZSTD_isError(cSize)) return cSize;
                 ip = iend;
                 op += cSize;
                 zcs->frameEnded = 1;
                 ZSTD_startNewCompression(zcs);
                 someMoreWork = 0; break;
             }
             /* complete loading into inBuffer */
             {   size_t const toLoad = zcs->inBuffTarget - zcs->inBuffPos;
                 size_t const loaded = ZSTD_limitCopy(
                                         zcs->inBuff + zcs->inBuffPos, toLoad,
                                         ip, iend-ip);
                 zcs->inBuffPos += loaded;
                 ip += loaded;
                 if ( (flushMode == ZSTD_e_continue)
                   && (zcs->inBuffPos < zcs->inBuffTarget) ) {
                     /* not enough input to fill full block : stop here */
                     someMoreWork = 0; break;
                 }
                 if ( (flushMode == ZSTD_e_flush)
                   && (zcs->inBuffPos == zcs->inToCompress) ) {
                     /* empty */
                     someMoreWork = 0; break;
                 }
             }
             /* compress current block (note : this stage cannot be stopped in the middle) */
             DEBUGLOG(5, "stream compression stage (flushMode==%u)", flushMode);
             {   void* cDst;
                 size_t cSize;
                 size_t const iSize = zcs->inBuffPos - zcs->inToCompress;
                 size_t oSize = oend-op;
                 unsigned const lastBlock = (flushMode == ZSTD_e_end) && (ip==iend);
                 if (oSize >= ZSTD_compressBound(iSize))
                     cDst = op;   /* compress into output buffer, to skip flush stage */
                 else
                     cDst = zcs->outBuff, oSize = zcs->outBuffSize;
                 cSize = lastBlock ?
                         ZSTD_compressEnd(zcs, cDst, oSize,
                                     zcs->inBuff + zcs->inToCompress, iSize) :
                         ZSTD_compressContinue(zcs, cDst, oSize,
                                     zcs->inBuff + zcs->inToCompress, iSize);
                 if (ZSTD_isError(cSize)) return cSize;
                 zcs->frameEnded = lastBlock;
                 /* prepare next block */
                 zcs->inBuffTarget = zcs->inBuffPos + zcs->blockSize;
                 if (zcs->inBuffTarget > zcs->inBuffSize)
                     zcs->inBuffPos = 0, zcs->inBuffTarget = zcs->blockSize;
                 DEBUGLOG(5, "inBuffTarget:%u / inBuffSize:%u",
                          (U32)zcs->inBuffTarget, (U32)zcs->inBuffSize);
                 if (!lastBlock)
                     assert(zcs->inBuffTarget <= zcs->inBuffSize);
                 zcs->inToCompress = zcs->inBuffPos;
                 if (cDst == op) {  /* no need to flush */
                     op += cSize;
                     if (zcs->frameEnded) {
                         DEBUGLOG(5, "Frame completed directly in outBuffer");
                         someMoreWork = 0;
                         ZSTD_startNewCompression(zcs);
                     }
                     break;
                 }
                 zcs->outBuffContentSize = cSize;
                 zcs->outBuffFlushedSize = 0;
                 zcs->streamStage = zcss_flush; /* pass-through to flush stage */
             }
 	    /* fall-through */
         case zcss_flush:
             DEBUGLOG(5, "flush stage");
             {   size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
                 size_t const flushed = ZSTD_limitCopy(op, oend-op,
                             zcs->outBuff + zcs->outBuffFlushedSize, toFlush);
                 DEBUGLOG(5, "toFlush: %u into %u ==> flushed: %u",
                             (U32)toFlush, (U32)(oend-op), (U32)flushed);
                 op += flushed;
                 zcs->outBuffFlushedSize += flushed;
                 if (toFlush!=flushed) {
                     /* flush not fully completed, presumably because dst is too small */
                     assert(op==oend);
                     someMoreWork = 0;
                     break;
                 }
                 zcs->outBuffContentSize = zcs->outBuffFlushedSize = 0;
                 if (zcs->frameEnded) {
                     DEBUGLOG(5, "Frame completed on flush");
                     someMoreWork = 0;
                     ZSTD_startNewCompression(zcs);
                     break;
                 }
                 zcs->streamStage = zcss_load;
                 break;
             }
 
         default: /* impossible */
             assert(0);
         }
     }
 
     input->pos = ip - istart;
     output->pos = op - ostart;
     if (zcs->frameEnded) return 0;
     {   size_t hintInSize = zcs->inBuffTarget - zcs->inBuffPos;
         if (hintInSize==0) hintInSize = zcs->blockSize;
         return hintInSize;
     }
 }
 
 size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
 {
     /* check conditions */
     if (output->pos > output->size) return ERROR(GENERIC);
     if (input->pos  > input->size)  return ERROR(GENERIC);
 
     return ZSTD_compressStream_generic(zcs, output, input, ZSTD_e_continue);
 }
 
 
 size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
                               ZSTD_outBuffer* output,
                               ZSTD_inBuffer* input,
                               ZSTD_EndDirective endOp)
 {
-    DEBUGLOG(5, "ZSTD_compress_generic");
+    DEBUGLOG(5, "ZSTD_compress_generic, endOp=%u ", (U32)endOp);
     /* check conditions */
     if (output->pos > output->size) return ERROR(GENERIC);
     if (input->pos  > input->size)  return ERROR(GENERIC);
     assert(cctx!=NULL);
 
     /* transparent initialization stage */
     if (cctx->streamStage == zcss_init) {
-        ZSTD_prefixDict const prefixDict = cctx->prefixDict;
         ZSTD_CCtx_params params = cctx->requestedParams;
-        params.cParams = ZSTD_getCParamsFromCCtxParams(
-                cctx->requestedParams, cctx->pledgedSrcSizePlusOne-1, 0 /*dictSize*/);
+        ZSTD_prefixDict const prefixDict = cctx->prefixDict;
         memset(&cctx->prefixDict, 0, sizeof(cctx->prefixDict));  /* single usage */
         assert(prefixDict.dict==NULL || cctx->cdict==NULL);   /* only one can be set */
         DEBUGLOG(4, "ZSTD_compress_generic : transparent init stage");
+        if (endOp == ZSTD_e_end) cctx->pledgedSrcSizePlusOne = input->size + 1;  /* auto-fix pledgedSrcSize */
+        params.cParams = ZSTD_getCParamsFromCCtxParams(
+                cctx->requestedParams, cctx->pledgedSrcSizePlusOne-1, 0 /*dictSize*/);
 
 #ifdef ZSTD_MULTITHREAD
+        if ((cctx->pledgedSrcSizePlusOne-1) <= ZSTDMT_JOBSIZE_MIN)
+            params.nbThreads = 1; /* do not invoke multi-threading when src size is too small */
         if (params.nbThreads > 1) {
-            if (cctx->mtctx == NULL || cctx->appliedParams.nbThreads != params.nbThreads) {
+            if (cctx->mtctx == NULL || (params.nbThreads != ZSTDMT_getNbThreads(cctx->mtctx))) {
+                DEBUGLOG(4, "ZSTD_compress_generic: creating new mtctx for nbThreads=%u (previous: %u)",
+                            params.nbThreads, ZSTDMT_getNbThreads(cctx->mtctx));
                 ZSTDMT_freeCCtx(cctx->mtctx);
                 cctx->mtctx = ZSTDMT_createCCtx_advanced(params.nbThreads, cctx->customMem);
                 if (cctx->mtctx == NULL) return ERROR(memory_allocation);
             }
             DEBUGLOG(4, "call ZSTDMT_initCStream_internal as nbThreads=%u", params.nbThreads);
             CHECK_F( ZSTDMT_initCStream_internal(
-                             cctx->mtctx,
-                             prefixDict.dict, prefixDict.dictSize, ZSTD_dm_rawContent,
-                             cctx->cdict, params, cctx->pledgedSrcSizePlusOne-1) );
+                        cctx->mtctx,
+                        prefixDict.dict, prefixDict.dictSize, ZSTD_dm_rawContent,
+                        cctx->cdict, params, cctx->pledgedSrcSizePlusOne-1) );
             cctx->streamStage = zcss_load;
             cctx->appliedParams.nbThreads = params.nbThreads;
         } else
 #endif
-        {
-            CHECK_F( ZSTD_resetCStream_internal(
+        {   CHECK_F( ZSTD_resetCStream_internal(
                              cctx, prefixDict.dict, prefixDict.dictSize,
                              prefixDict.dictMode, cctx->cdict, params,
                              cctx->pledgedSrcSizePlusOne-1) );
+            assert(cctx->streamStage == zcss_load);
+            assert(cctx->appliedParams.nbThreads <= 1);
     }   }
 
     /* compression stage */
 #ifdef ZSTD_MULTITHREAD
     if (cctx->appliedParams.nbThreads > 1) {
         size_t const flushMin = ZSTDMT_compressStream_generic(cctx->mtctx, output, input, endOp);
-        DEBUGLOG(5, "ZSTDMT_compressStream_generic result : %u", (U32)flushMin);
         if ( ZSTD_isError(flushMin)
           || (endOp == ZSTD_e_end && flushMin == 0) ) { /* compression completed */
             ZSTD_startNewCompression(cctx);
         }
         return flushMin;
     }
 #endif
     CHECK_F( ZSTD_compressStream_generic(cctx, output, input, endOp) );
     DEBUGLOG(5, "completed ZSTD_compress_generic");
     return cctx->outBuffContentSize - cctx->outBuffFlushedSize; /* remaining to flush */
 }
 
 size_t ZSTD_compress_generic_simpleArgs (
                             ZSTD_CCtx* cctx,
                             void* dst, size_t dstCapacity, size_t* dstPos,
                       const void* src, size_t srcSize, size_t* srcPos,
                             ZSTD_EndDirective endOp)
 {
     ZSTD_outBuffer output = { dst, dstCapacity, *dstPos };
     ZSTD_inBuffer  input  = { src, srcSize, *srcPos };
     /* ZSTD_compress_generic() will check validity of dstPos and srcPos */
     size_t const cErr = ZSTD_compress_generic(cctx, &output, &input, endOp);
     *dstPos = output.pos;
     *srcPos = input.pos;
     return cErr;
 }
 
 
 /*======   Finalize   ======*/
 
 /*! ZSTD_flushStream() :
 *   @return : amount of data remaining to flush */
 size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output)
 {
     ZSTD_inBuffer input = { NULL, 0, 0 };
     if (output->pos > output->size) return ERROR(GENERIC);
     CHECK_F( ZSTD_compressStream_generic(zcs, output, &input, ZSTD_e_flush) );
     return zcs->outBuffContentSize - zcs->outBuffFlushedSize;  /* remaining to flush */
 }
 
 
 size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output)
 {
     ZSTD_inBuffer input = { NULL, 0, 0 };
     if (output->pos > output->size) return ERROR(GENERIC);
     CHECK_F( ZSTD_compressStream_generic(zcs, output, &input, ZSTD_e_end) );
     {   size_t const lastBlockSize = zcs->frameEnded ? 0 : ZSTD_BLOCKHEADERSIZE;
         size_t const checksumSize = zcs->frameEnded ? 0 : zcs->appliedParams.fParams.checksumFlag * 4;
         size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize + lastBlockSize + checksumSize;
-        DEBUGLOG(5, "ZSTD_endStream : remaining to flush : %u",
-                (unsigned)toFlush);
+        DEBUGLOG(4, "ZSTD_endStream : remaining to flush : %u", (U32)toFlush);
         return toFlush;
     }
 }
 
 
 /*-=====  Pre-defined compression levels  =====-*/
 
 #define ZSTD_MAX_CLEVEL     22
 int ZSTD_maxCLevel(void) { return ZSTD_MAX_CLEVEL; }
 
 static const ZSTD_compressionParameters ZSTD_defaultCParameters[4][ZSTD_MAX_CLEVEL+1] = {
 {   /* "default" - guarantees a monotonically increasing memory budget */
     /* W,  C,  H,  S,  L, TL, strat */
     { 18, 12, 12,  1,  7, 16, ZSTD_fast    },  /* level  0 - never used */
     { 19, 13, 14,  1,  7, 16, ZSTD_fast    },  /* level  1 */
     { 19, 15, 16,  1,  6, 16, ZSTD_fast    },  /* level  2 */
     { 20, 16, 17,  1,  5, 16, ZSTD_dfast   },  /* level  3 */
     { 20, 17, 18,  1,  5, 16, ZSTD_dfast   },  /* level  4 */
     { 20, 17, 18,  2,  5, 16, ZSTD_greedy  },  /* level  5 */
     { 21, 17, 19,  2,  5, 16, ZSTD_lazy    },  /* level  6 */
     { 21, 18, 19,  3,  5, 16, ZSTD_lazy    },  /* level  7 */
     { 21, 18, 20,  3,  5, 16, ZSTD_lazy2   },  /* level  8 */
     { 21, 19, 20,  3,  5, 16, ZSTD_lazy2   },  /* level  9 */
     { 21, 19, 21,  4,  5, 16, ZSTD_lazy2   },  /* level 10 */
     { 22, 20, 22,  4,  5, 16, ZSTD_lazy2   },  /* level 11 */
     { 22, 20, 22,  5,  5, 16, ZSTD_lazy2   },  /* level 12 */
     { 22, 21, 22,  5,  5, 16, ZSTD_lazy2   },  /* level 13 */
     { 22, 21, 22,  6,  5, 16, ZSTD_lazy2   },  /* level 14 */
-    { 22, 21, 22,  5,  5, 16, ZSTD_btlazy2 },  /* level 15 */
-    { 23, 22, 22,  5,  5, 16, ZSTD_btlazy2 },  /* level 16 */
-    { 23, 22, 22,  4,  5, 24, ZSTD_btopt   },  /* level 17 */
-    { 23, 22, 22,  5,  4, 32, ZSTD_btopt   },  /* level 18 */
-    { 23, 23, 22,  6,  3, 48, ZSTD_btopt   },  /* level 19 */
-    { 25, 25, 23,  7,  3, 64, ZSTD_btultra },  /* level 20 */
+    { 22, 21, 22,  4,  5, 16, ZSTD_btlazy2 },  /* level 15 */
+    { 22, 21, 22,  4,  5, 48, ZSTD_btopt   },  /* level 16 */
+    { 23, 22, 22,  4,  4, 48, ZSTD_btopt   },  /* level 17 */
+    { 23, 22, 22,  5,  3, 64, ZSTD_btopt   },  /* level 18 */
+    { 23, 23, 22,  7,  3,128, ZSTD_btopt   },  /* level 19 */
+    { 25, 25, 23,  7,  3,128, ZSTD_btultra },  /* level 20 */
     { 26, 26, 24,  7,  3,256, ZSTD_btultra },  /* level 21 */
     { 27, 27, 25,  9,  3,512, ZSTD_btultra },  /* level 22 */
 },
 {   /* for srcSize <= 256 KB */
     /* W,  C,  H,  S,  L,  T, strat */
     {  0,  0,  0,  0,  0,  0, ZSTD_fast    },  /* level  0 - not used */
     { 18, 13, 14,  1,  6,  8, ZSTD_fast    },  /* level  1 */
     { 18, 14, 13,  1,  5,  8, ZSTD_dfast   },  /* level  2 */
     { 18, 16, 15,  1,  5,  8, ZSTD_dfast   },  /* level  3 */
     { 18, 15, 17,  1,  5,  8, ZSTD_greedy  },  /* level  4.*/
     { 18, 16, 17,  4,  5,  8, ZSTD_greedy  },  /* level  5.*/
     { 18, 16, 17,  3,  5,  8, ZSTD_lazy    },  /* level  6.*/
     { 18, 17, 17,  4,  4,  8, ZSTD_lazy    },  /* level  7 */
     { 18, 17, 17,  4,  4,  8, ZSTD_lazy2   },  /* level  8 */
     { 18, 17, 17,  5,  4,  8, ZSTD_lazy2   },  /* level  9 */
     { 18, 17, 17,  6,  4,  8, ZSTD_lazy2   },  /* level 10 */
     { 18, 18, 17,  6,  4,  8, ZSTD_lazy2   },  /* level 11.*/
     { 18, 18, 17,  7,  4,  8, ZSTD_lazy2   },  /* level 12.*/
     { 18, 19, 17,  6,  4,  8, ZSTD_btlazy2 },  /* level 13 */
     { 18, 18, 18,  4,  4, 16, ZSTD_btopt   },  /* level 14.*/
     { 18, 18, 18,  4,  3, 16, ZSTD_btopt   },  /* level 15.*/
     { 18, 19, 18,  6,  3, 32, ZSTD_btopt   },  /* level 16.*/
     { 18, 19, 18,  8,  3, 64, ZSTD_btopt   },  /* level 17.*/
     { 18, 19, 18,  9,  3,128, ZSTD_btopt   },  /* level 18.*/
     { 18, 19, 18, 10,  3,256, ZSTD_btopt   },  /* level 19.*/
     { 18, 19, 18, 11,  3,512, ZSTD_btultra },  /* level 20.*/
     { 18, 19, 18, 12,  3,512, ZSTD_btultra },  /* level 21.*/
     { 18, 19, 18, 13,  3,512, ZSTD_btultra },  /* level 22.*/
 },
 {   /* for srcSize <= 128 KB */
     /* W,  C,  H,  S,  L,  T, strat */
     { 17, 12, 12,  1,  7,  8, ZSTD_fast    },  /* level  0 - not used */
     { 17, 12, 13,  1,  6,  8, ZSTD_fast    },  /* level  1 */
     { 17, 13, 16,  1,  5,  8, ZSTD_fast    },  /* level  2 */
     { 17, 16, 16,  2,  5,  8, ZSTD_dfast   },  /* level  3 */
     { 17, 13, 15,  3,  4,  8, ZSTD_greedy  },  /* level  4 */
     { 17, 15, 17,  4,  4,  8, ZSTD_greedy  },  /* level  5 */
     { 17, 16, 17,  3,  4,  8, ZSTD_lazy    },  /* level  6 */
     { 17, 15, 17,  4,  4,  8, ZSTD_lazy2   },  /* level  7 */
     { 17, 17, 17,  4,  4,  8, ZSTD_lazy2   },  /* level  8 */
     { 17, 17, 17,  5,  4,  8, ZSTD_lazy2   },  /* level  9 */
     { 17, 17, 17,  6,  4,  8, ZSTD_lazy2   },  /* level 10 */
     { 17, 17, 17,  7,  4,  8, ZSTD_lazy2   },  /* level 11 */
     { 17, 17, 17,  8,  4,  8, ZSTD_lazy2   },  /* level 12 */
     { 17, 18, 17,  6,  4,  8, ZSTD_btlazy2 },  /* level 13.*/
     { 17, 17, 17,  7,  3,  8, ZSTD_btopt   },  /* level 14.*/
     { 17, 17, 17,  7,  3, 16, ZSTD_btopt   },  /* level 15.*/
     { 17, 18, 17,  7,  3, 32, ZSTD_btopt   },  /* level 16.*/
     { 17, 18, 17,  7,  3, 64, ZSTD_btopt   },  /* level 17.*/
     { 17, 18, 17,  7,  3,256, ZSTD_btopt   },  /* level 18.*/
     { 17, 18, 17,  8,  3,256, ZSTD_btopt   },  /* level 19.*/
     { 17, 18, 17,  9,  3,256, ZSTD_btultra },  /* level 20.*/
     { 17, 18, 17, 10,  3,256, ZSTD_btultra },  /* level 21.*/
     { 17, 18, 17, 11,  3,512, ZSTD_btultra },  /* level 22.*/
 },
 {   /* for srcSize <= 16 KB */
     /* W,  C,  H,  S,  L,  T, strat */
     { 14, 12, 12,  1,  7,  6, ZSTD_fast    },  /* level  0 - not used */
     { 14, 14, 14,  1,  6,  6, ZSTD_fast    },  /* level  1 */
     { 14, 14, 14,  1,  4,  6, ZSTD_fast    },  /* level  2 */
     { 14, 14, 14,  1,  4,  6, ZSTD_dfast   },  /* level  3.*/
     { 14, 14, 14,  4,  4,  6, ZSTD_greedy  },  /* level  4.*/
     { 14, 14, 14,  3,  4,  6, ZSTD_lazy    },  /* level  5.*/
     { 14, 14, 14,  4,  4,  6, ZSTD_lazy2   },  /* level  6 */
     { 14, 14, 14,  5,  4,  6, ZSTD_lazy2   },  /* level  7 */
     { 14, 14, 14,  6,  4,  6, ZSTD_lazy2   },  /* level  8.*/
     { 14, 15, 14,  6,  4,  6, ZSTD_btlazy2 },  /* level  9.*/
     { 14, 15, 14,  3,  3,  6, ZSTD_btopt   },  /* level 10.*/
     { 14, 15, 14,  6,  3,  8, ZSTD_btopt   },  /* level 11.*/
     { 14, 15, 14,  6,  3, 16, ZSTD_btopt   },  /* level 12.*/
     { 14, 15, 14,  6,  3, 24, ZSTD_btopt   },  /* level 13.*/
     { 14, 15, 15,  6,  3, 48, ZSTD_btopt   },  /* level 14.*/
     { 14, 15, 15,  6,  3, 64, ZSTD_btopt   },  /* level 15.*/
     { 14, 15, 15,  6,  3, 96, ZSTD_btopt   },  /* level 16.*/
     { 14, 15, 15,  6,  3,128, ZSTD_btopt   },  /* level 17.*/
     { 14, 15, 15,  6,  3,256, ZSTD_btopt   },  /* level 18.*/
     { 14, 15, 15,  7,  3,256, ZSTD_btopt   },  /* level 19.*/
     { 14, 15, 15,  8,  3,256, ZSTD_btultra },  /* level 20.*/
     { 14, 15, 15,  9,  3,256, ZSTD_btultra },  /* level 21.*/
     { 14, 15, 15, 10,  3,256, ZSTD_btultra },  /* level 22.*/
 },
 };
 
 #if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=1)
 /* This function just controls
  * the monotonic memory budget increase of ZSTD_defaultCParameters[0].
  * Run once, on first ZSTD_getCParams() usage, if ZSTD_DEBUG is enabled
  */
 MEM_STATIC void ZSTD_check_compressionLevel_monotonicIncrease_memoryBudget(void)
 {
     int level;
     for (level=1; level=1)
     static int g_monotonicTest = 1;
     if (g_monotonicTest) {
         ZSTD_check_compressionLevel_monotonicIncrease_memoryBudget();
         g_monotonicTest=0;
     }
 #endif
 
+    DEBUGLOG(4, "ZSTD_getCParams: cLevel=%i, srcSize=%u, dictSize=%u => table %u",
+                compressionLevel, (U32)srcSizeHint, (U32)dictSize, tableID);
     if (compressionLevel <= 0) compressionLevel = ZSTD_CLEVEL_DEFAULT;   /* 0 == default; no negative compressionLevel yet */
     if (compressionLevel > ZSTD_MAX_CLEVEL) compressionLevel = ZSTD_MAX_CLEVEL;
     { ZSTD_compressionParameters const cp = ZSTD_defaultCParameters[tableID][compressionLevel];
       return ZSTD_adjustCParams_internal(cp, srcSizeHint, dictSize); }
 
 }
 
 /*! ZSTD_getParams() :
 *   same as ZSTD_getCParams(), but @return a `ZSTD_parameters` object (instead of `ZSTD_compressionParameters`).
 *   All fields of `ZSTD_frameParameters` are set to default (0) */
 ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize) {
     ZSTD_parameters params;
     ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, srcSizeHint, dictSize);
     memset(¶ms, 0, sizeof(params));
     params.cParams = cParams;
+    params.fParams.contentSizeFlag = 1;
     return params;
 }
Index: head/sys/contrib/zstd/lib/compress/zstd_compress_internal.h
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_compress_internal.h	(nonexistent)
+++ head/sys/contrib/zstd/lib/compress/zstd_compress_internal.h	(revision 330894)
@@ -0,0 +1,462 @@
+/*
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+/* This header contains definitions
+ * that shall **only** be used by modules within lib/compress.
+ */
+
+#ifndef ZSTD_COMPRESS_H
+#define ZSTD_COMPRESS_H
+
+/*-*************************************
+*  Dependencies
+***************************************/
+#include "zstd_internal.h"
+#ifdef ZSTD_MULTITHREAD
+#  include "zstdmt_compress.h"
+#endif
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+/*-*************************************
+*  Constants
+***************************************/
+static const U32 g_searchStrength = 8;
+#define HASH_READ_SIZE 8
+
+
+/*-*************************************
+*  Context memory management
+***************************************/
+typedef enum { ZSTDcs_created=0, ZSTDcs_init, ZSTDcs_ongoing, ZSTDcs_ending } ZSTD_compressionStage_e;
+typedef enum { zcss_init=0, zcss_load, zcss_flush } ZSTD_cStreamStage;
+
+typedef struct ZSTD_prefixDict_s {
+    const void* dict;
+    size_t dictSize;
+    ZSTD_dictMode_e dictMode;
+} ZSTD_prefixDict;
+
+typedef struct {
+    U32 hufCTable[HUF_CTABLE_SIZE_U32(255)];
+    FSE_CTable offcodeCTable[FSE_CTABLE_SIZE_U32(OffFSELog, MaxOff)];
+    FSE_CTable matchlengthCTable[FSE_CTABLE_SIZE_U32(MLFSELog, MaxML)];
+    FSE_CTable litlengthCTable[FSE_CTABLE_SIZE_U32(LLFSELog, MaxLL)];
+    U32 workspace[HUF_WORKSPACE_SIZE_U32];
+    HUF_repeat hufCTable_repeatMode;
+    FSE_repeat offcode_repeatMode;
+    FSE_repeat matchlength_repeatMode;
+    FSE_repeat litlength_repeatMode;
+} ZSTD_entropyCTables_t;
+
+typedef struct {
+    U32 off;
+    U32 len;
+} ZSTD_match_t;
+
+typedef struct {
+    int price;
+    U32 off;
+    U32 mlen;
+    U32 litlen;
+    U32 rep[ZSTD_REP_NUM];
+} ZSTD_optimal_t;
+
+typedef struct {
+    /* All tables are allocated inside cctx->workspace by ZSTD_resetCCtx_internal() */
+    U32* litFreq;               /* table of literals statistics, of size 256 */
+    U32* litLengthFreq;         /* table of litLength statistics, of size (MaxLL+1) */
+    U32* matchLengthFreq;       /* table of matchLength statistics, of size (MaxML+1) */
+    U32* offCodeFreq;           /* table of offCode statistics, of size (MaxOff+1) */
+    ZSTD_match_t* matchTable;   /* list of found matches, of size ZSTD_OPT_NUM+1 */
+    ZSTD_optimal_t* priceTable; /* All positions tracked by optimal parser, of size ZSTD_OPT_NUM+1 */
+
+    U32  litSum;                 /* nb of literals */
+    U32  litLengthSum;           /* nb of litLength codes */
+    U32  matchLengthSum;         /* nb of matchLength codes */
+    U32  offCodeSum;             /* nb of offset codes */
+    /* begin updated by ZSTD_setLog2Prices */
+    U32  log2litSum;             /* pow2 to compare log2(litfreq) to */
+    U32  log2litLengthSum;       /* pow2 to compare log2(llfreq) to */
+    U32  log2matchLengthSum;     /* pow2 to compare log2(mlfreq) to */
+    U32  log2offCodeSum;         /* pow2 to compare log2(offreq) to */
+    /* end : updated by ZSTD_setLog2Prices */
+    U32  staticPrices;           /* prices follow a pre-defined cost structure, statistics are irrelevant */
+} optState_t;
+
+typedef struct {
+    U32 offset;
+    U32 checksum;
+} ldmEntry_t;
+
+typedef struct {
+    ldmEntry_t* hashTable;
+    BYTE* bucketOffsets;    /* Next position in bucket to insert entry */
+    U64 hashPower;          /* Used to compute the rolling hash.
+                             * Depends on ldmParams.minMatchLength */
+} ldmState_t;
+
+typedef struct {
+    U32 enableLdm;          /* 1 if enable long distance matching */
+    U32 hashLog;            /* Log size of hashTable */
+    U32 bucketSizeLog;      /* Log bucket size for collision resolution, at most 8 */
+    U32 minMatchLength;     /* Minimum match length */
+    U32 hashEveryLog;       /* Log number of entries to skip */
+} ldmParams_t;
+
+struct ZSTD_CCtx_params_s {
+    ZSTD_format_e format;
+    ZSTD_compressionParameters cParams;
+    ZSTD_frameParameters fParams;
+
+    int compressionLevel;
+    U32 forceWindow;           /* force back-references to respect limit of
+                                * 1< 63) ? ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];
+}
+
+/* ZSTD_MLcode() :
+ * note : mlBase = matchLength - MINMATCH;
+ *        because it's the format it's stored in seqStore->sequences */
+MEM_STATIC U32 ZSTD_MLcode(U32 mlBase)
+{
+    static const BYTE ML_Code[128] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,
+                                      16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
+                                      32, 32, 33, 33, 34, 34, 35, 35, 36, 36, 36, 36, 37, 37, 37, 37,
+                                      38, 38, 38, 38, 38, 38, 38, 38, 39, 39, 39, 39, 39, 39, 39, 39,
+                                      40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,
+                                      41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41,
+                                      42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42,
+                                      42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42 };
+    static const U32 ML_deltaCode = 36;
+    return (mlBase > 127) ? ZSTD_highbit32(mlBase) + ML_deltaCode : ML_Code[mlBase];
+}
+
+/*! ZSTD_storeSeq() :
+ *  Store a sequence (literal length, literals, offset code and match length code) into seqStore_t.
+ *  `offsetCode` : distance to match + 3 (values 1-3 are repCodes).
+ *  `mlBase` : matchLength - MINMATCH
+*/
+MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const void* literals, U32 offsetCode, size_t mlBase)
+{
+#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG >= 6)
+    static const BYTE* g_start = NULL;
+    if (g_start==NULL) g_start = (const BYTE*)literals;  /* note : index only works for compression within a single segment */
+    {   U32 const pos = (U32)((const BYTE*)literals - g_start);
+        DEBUGLOG(6, "Cpos%7u :%3u literals, match%3u bytes at dist.code%7u",
+               pos, (U32)litLength, (U32)mlBase+MINMATCH, (U32)offsetCode);
+    }
+#endif
+    /* copy Literals */
+    assert(seqStorePtr->lit + litLength <= seqStorePtr->litStart + 128 KB);
+    ZSTD_wildcopy(seqStorePtr->lit, literals, litLength);
+    seqStorePtr->lit += litLength;
+
+    /* literal Length */
+    if (litLength>0xFFFF) {
+        assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */
+        seqStorePtr->longLengthID = 1;
+        seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
+    }
+    seqStorePtr->sequences[0].litLength = (U16)litLength;
+
+    /* match offset */
+    seqStorePtr->sequences[0].offset = offsetCode + 1;
+
+    /* match Length */
+    if (mlBase>0xFFFF) {
+        assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */
+        seqStorePtr->longLengthID = 2;
+        seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
+    }
+    seqStorePtr->sequences[0].matchLength = (U16)mlBase;
+
+    seqStorePtr->sequences++;
+}
+
+
+/*-*************************************
+*  Match length counter
+***************************************/
+static unsigned ZSTD_NbCommonBytes (size_t val)
+{
+    if (MEM_isLittleEndian()) {
+        if (MEM_64bits()) {
+#       if defined(_MSC_VER) && defined(_WIN64)
+            unsigned long r = 0;
+            _BitScanForward64( &r, (U64)val );
+            return (unsigned)(r>>3);
+#       elif defined(__GNUC__) && (__GNUC__ >= 4)
+            return (__builtin_ctzll((U64)val) >> 3);
+#       else
+            static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2,
+                                                     0, 3, 1, 3, 1, 4, 2, 7,
+                                                     0, 2, 3, 6, 1, 5, 3, 5,
+                                                     1, 3, 4, 4, 2, 5, 6, 7,
+                                                     7, 0, 1, 2, 3, 3, 4, 6,
+                                                     2, 6, 5, 5, 3, 4, 5, 6,
+                                                     7, 1, 2, 4, 6, 4, 4, 5,
+                                                     7, 2, 6, 5, 7, 6, 7, 7 };
+            return DeBruijnBytePos[((U64)((val & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58];
+#       endif
+        } else { /* 32 bits */
+#       if defined(_MSC_VER)
+            unsigned long r=0;
+            _BitScanForward( &r, (U32)val );
+            return (unsigned)(r>>3);
+#       elif defined(__GNUC__) && (__GNUC__ >= 3)
+            return (__builtin_ctz((U32)val) >> 3);
+#       else
+            static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0,
+                                                     3, 2, 2, 1, 3, 2, 0, 1,
+                                                     3, 3, 1, 2, 2, 2, 2, 0,
+                                                     3, 1, 2, 0, 1, 0, 1, 1 };
+            return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
+#       endif
+        }
+    } else {  /* Big Endian CPU */
+        if (MEM_64bits()) {
+#       if defined(_MSC_VER) && defined(_WIN64)
+            unsigned long r = 0;
+            _BitScanReverse64( &r, val );
+            return (unsigned)(r>>3);
+#       elif defined(__GNUC__) && (__GNUC__ >= 4) && __has_builtin(__builtin_clzll)
+            return (__builtin_clzll(val) >> 3);
+#       else
+            unsigned r;
+            const unsigned n32 = sizeof(size_t)*4;   /* calculate this way due to compiler complaining in 32-bits mode */
+            if (!(val>>n32)) { r=4; } else { r=0; val>>=n32; }
+            if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
+            r += (!val);
+            return r;
+#       endif
+        } else { /* 32 bits */
+#       if defined(_MSC_VER)
+            unsigned long r = 0;
+            _BitScanReverse( &r, (unsigned long)val );
+            return (unsigned)(r>>3);
+#       elif defined(__GNUC__) && (__GNUC__ >= 3) && __has_builtin(__builtin_clz)
+            return (__builtin_clz((U32)val) >> 3);
+#       else
+            unsigned r;
+            if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
+            r += (!val);
+            return r;
+#       endif
+    }   }
+}
+
+
+MEM_STATIC size_t ZSTD_count(const BYTE* pIn, const BYTE* pMatch, const BYTE* const pInLimit)
+{
+    const BYTE* const pStart = pIn;
+    const BYTE* const pInLoopLimit = pInLimit - (sizeof(size_t)-1);
+
+    if (pIn < pInLoopLimit) {
+        { size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn);
+          if (diff) return ZSTD_NbCommonBytes(diff); }
+        pIn+=sizeof(size_t); pMatch+=sizeof(size_t);
+        while (pIn < pInLoopLimit) {
+            size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn);
+            if (!diff) { pIn+=sizeof(size_t); pMatch+=sizeof(size_t); continue; }
+            pIn += ZSTD_NbCommonBytes(diff);
+            return (size_t)(pIn - pStart);
+    }   }
+    if (MEM_64bits() && (pIn<(pInLimit-3)) && (MEM_read32(pMatch) == MEM_read32(pIn))) { pIn+=4; pMatch+=4; }
+    if ((pIn<(pInLimit-1)) && (MEM_read16(pMatch) == MEM_read16(pIn))) { pIn+=2; pMatch+=2; }
+    if ((pIn> (32-h) ; }
+MEM_STATIC size_t ZSTD_hash3Ptr(const void* ptr, U32 h) { return ZSTD_hash3(MEM_readLE32(ptr), h); } /* only in zstd_opt.h */
+
+static const U32 prime4bytes = 2654435761U;
+static U32    ZSTD_hash4(U32 u, U32 h) { return (u * prime4bytes) >> (32-h) ; }
+static size_t ZSTD_hash4Ptr(const void* ptr, U32 h) { return ZSTD_hash4(MEM_read32(ptr), h); }
+
+static const U64 prime5bytes = 889523592379ULL;
+static size_t ZSTD_hash5(U64 u, U32 h) { return (size_t)(((u  << (64-40)) * prime5bytes) >> (64-h)) ; }
+static size_t ZSTD_hash5Ptr(const void* p, U32 h) { return ZSTD_hash5(MEM_readLE64(p), h); }
+
+static const U64 prime6bytes = 227718039650203ULL;
+static size_t ZSTD_hash6(U64 u, U32 h) { return (size_t)(((u  << (64-48)) * prime6bytes) >> (64-h)) ; }
+static size_t ZSTD_hash6Ptr(const void* p, U32 h) { return ZSTD_hash6(MEM_readLE64(p), h); }
+
+static const U64 prime7bytes = 58295818150454627ULL;
+static size_t ZSTD_hash7(U64 u, U32 h) { return (size_t)(((u  << (64-56)) * prime7bytes) >> (64-h)) ; }
+static size_t ZSTD_hash7Ptr(const void* p, U32 h) { return ZSTD_hash7(MEM_readLE64(p), h); }
+
+static const U64 prime8bytes = 0xCF1BBCDCB7A56463ULL;
+static size_t ZSTD_hash8(U64 u, U32 h) { return (size_t)(((u) * prime8bytes) >> (64-h)) ; }
+static size_t ZSTD_hash8Ptr(const void* p, U32 h) { return ZSTD_hash8(MEM_readLE64(p), h); }
+
+MEM_STATIC size_t ZSTD_hashPtr(const void* p, U32 hBits, U32 mls)
+{
+    switch(mls)
+    {
+    default:
+    case 4: return ZSTD_hash4Ptr(p, hBits);
+    case 5: return ZSTD_hash5Ptr(p, hBits);
+    case 6: return ZSTD_hash6Ptr(p, hBits);
+    case 7: return ZSTD_hash7Ptr(p, hBits);
+    case 8: return ZSTD_hash8Ptr(p, hBits);
+    }
+}
+
+#if defined (__cplusplus)
+}
+#endif
+
+
+/* ==============================================================
+ * Private declarations
+ * These prototypes shall only be called from within lib/compress
+ * ============================================================== */
+
+/*! ZSTD_initCStream_internal() :
+ *  Private use only. Init streaming operation.
+ *  expects params to be valid.
+ *  must receive dict, or cdict, or none, but not both.
+ *  @return : 0, or an error code */
+size_t ZSTD_initCStream_internal(ZSTD_CStream* zcs,
+                     const void* dict, size_t dictSize,
+                     const ZSTD_CDict* cdict,
+                     ZSTD_CCtx_params  params, unsigned long long pledgedSrcSize);
+
+/*! ZSTD_compressStream_generic() :
+ *  Private use only. To be called from zstdmt_compress.c in single-thread mode. */
+size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
+                                   ZSTD_outBuffer* output,
+                                   ZSTD_inBuffer* input,
+                                   ZSTD_EndDirective const flushMode);
+
+/*! ZSTD_getCParamsFromCDict() :
+ *  as the name implies */
+ZSTD_compressionParameters ZSTD_getCParamsFromCDict(const ZSTD_CDict* cdict);
+
+/* ZSTD_compressBegin_advanced_internal() :
+ * Private use only. To be called from zstdmt_compress.c. */
+size_t ZSTD_compressBegin_advanced_internal(ZSTD_CCtx* cctx,
+                                    const void* dict, size_t dictSize,
+                                    ZSTD_dictMode_e dictMode,
+                                    const ZSTD_CDict* cdict,
+                                    ZSTD_CCtx_params params,
+                                    unsigned long long pledgedSrcSize);
+
+/* ZSTD_compress_advanced_internal() :
+ * Private use only. To be called from zstdmt_compress.c. */
+size_t ZSTD_compress_advanced_internal(ZSTD_CCtx* cctx,
+                                       void* dst, size_t dstCapacity,
+                                 const void* src, size_t srcSize,
+                                 const void* dict,size_t dictSize,
+                                 ZSTD_CCtx_params params);
+
+#endif /* ZSTD_COMPRESS_H */

Property changes on: head/sys/contrib/zstd/lib/compress/zstd_compress_internal.h
___________________________________________________________________
Added: svn:eol-style
## -0,0 +1 ##
+native
\ No newline at end of property
Added: svn:keywords
## -0,0 +1 ##
+FreeBSD=%H
\ No newline at end of property
Added: svn:mime-type
## -0,0 +1 ##
+text/plain
\ No newline at end of property
Index: head/sys/contrib/zstd/lib/compress/zstd_double_fast.c
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_double_fast.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_double_fast.c	(revision 330894)
@@ -1,308 +1,309 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
+#include "zstd_compress_internal.h"
 #include "zstd_double_fast.h"
 
 
 void ZSTD_fillDoubleHashTable(ZSTD_CCtx* cctx, const void* end, const U32 mls)
 {
     U32* const hashLarge = cctx->hashTable;
     U32  const hBitsL = cctx->appliedParams.cParams.hashLog;
     U32* const hashSmall = cctx->chainTable;
     U32  const hBitsS = cctx->appliedParams.cParams.chainLog;
     const BYTE* const base = cctx->base;
     const BYTE* ip = base + cctx->nextToUpdate;
     const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
     const size_t fastHashFillStep = 3;
 
     while(ip <= iend) {
         hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip - base);
         hashLarge[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip - base);
         ip += fastHashFillStep;
     }
 }
 
 
 FORCE_INLINE_TEMPLATE
 size_t ZSTD_compressBlock_doubleFast_generic(ZSTD_CCtx* cctx,
                                  const void* src, size_t srcSize,
                                  const U32 mls)
 {
     U32* const hashLong = cctx->hashTable;
     const U32 hBitsL = cctx->appliedParams.cParams.hashLog;
     U32* const hashSmall = cctx->chainTable;
     const U32 hBitsS = cctx->appliedParams.cParams.chainLog;
     seqStore_t* seqStorePtr = &(cctx->seqStore);
     const BYTE* const base = cctx->base;
     const BYTE* const istart = (const BYTE*)src;
     const BYTE* ip = istart;
     const BYTE* anchor = istart;
     const U32 lowestIndex = cctx->dictLimit;
     const BYTE* const lowest = base + lowestIndex;
     const BYTE* const iend = istart + srcSize;
     const BYTE* const ilimit = iend - HASH_READ_SIZE;
     U32 offset_1=seqStorePtr->rep[0], offset_2=seqStorePtr->rep[1];
     U32 offsetSaved = 0;
 
     /* init */
     ip += (ip==lowest);
     {   U32 const maxRep = (U32)(ip-lowest);
         if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
         if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
     }
 
     /* Main Search Loop */
     while (ip < ilimit) {   /* < instead of <=, because repcode check at (ip+1) */
         size_t mLength;
         size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8);
         size_t const h = ZSTD_hashPtr(ip, hBitsS, mls);
         U32 const current = (U32)(ip-base);
         U32 const matchIndexL = hashLong[h2];
         U32 const matchIndexS = hashSmall[h];
         const BYTE* matchLong = base + matchIndexL;
         const BYTE* match = base + matchIndexS;
         hashLong[h2] = hashSmall[h] = current;   /* update hash tables */
 
         assert(offset_1 <= current);   /* supposed guaranteed by construction */
         if ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))) {
             /* favor repcode */
             mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
             ip++;
             ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, 0, mLength-MINMATCH);
         } else {
             U32 offset;
             if ( (matchIndexL > lowestIndex) && (MEM_read64(matchLong) == MEM_read64(ip)) ) {
                 mLength = ZSTD_count(ip+8, matchLong+8, iend) + 8;
                 offset = (U32)(ip-matchLong);
                 while (((ip>anchor) & (matchLong>lowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
             } else if ( (matchIndexS > lowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) {
                 size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
                 U32 const matchIndexL3 = hashLong[hl3];
                 const BYTE* matchL3 = base + matchIndexL3;
                 hashLong[hl3] = current + 1;
                 if ( (matchIndexL3 > lowestIndex) && (MEM_read64(matchL3) == MEM_read64(ip+1)) ) {
                     mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8;
                     ip++;
                     offset = (U32)(ip-matchL3);
                     while (((ip>anchor) & (matchL3>lowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */
                 } else {
                     mLength = ZSTD_count(ip+4, match+4, iend) + 4;
                     offset = (U32)(ip-match);
                     while (((ip>anchor) & (match>lowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
                 }
             } else {
                 ip += ((ip-anchor) >> g_searchStrength) + 1;
                 continue;
             }
 
             offset_2 = offset_1;
             offset_1 = offset;
 
             ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
         }
 
         /* match found */
         ip += mLength;
         anchor = ip;
 
         if (ip <= ilimit) {
             /* Fill Table */
             hashLong[ZSTD_hashPtr(base+current+2, hBitsL, 8)] =
                 hashSmall[ZSTD_hashPtr(base+current+2, hBitsS, mls)] = current+2;  /* here because current+2 could be > iend-8 */
             hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] =
                 hashSmall[ZSTD_hashPtr(ip-2, hBitsS, mls)] = (U32)(ip-2-base);
 
             /* check immediate repcode */
             while ( (ip <= ilimit)
                  && ( (offset_2>0)
                  & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
                 /* store sequence */
                 size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
                 { U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; } /* swap offset_2 <=> offset_1 */
                 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base);
                 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base);
                 ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength-MINMATCH);
                 ip += rLength;
                 anchor = ip;
                 continue;   /* faster when present ... (?) */
     }   }   }
 
     /* save reps for next block */
     seqStorePtr->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved;
     seqStorePtr->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved;
 
     /* Return the last literals size */
     return iend - anchor;
 }
 
 
 size_t ZSTD_compressBlock_doubleFast(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
     const U32 mls = ctx->appliedParams.cParams.searchLength;
     switch(mls)
     {
     default: /* includes case 3 */
     case 4 :
         return ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 4);
     case 5 :
         return ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 5);
     case 6 :
         return ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 6);
     case 7 :
         return ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 7);
     }
 }
 
 
 static size_t ZSTD_compressBlock_doubleFast_extDict_generic(ZSTD_CCtx* ctx,
                                  const void* src, size_t srcSize,
                                  const U32 mls)
 {
     U32* const hashLong = ctx->hashTable;
     U32  const hBitsL = ctx->appliedParams.cParams.hashLog;
     U32* const hashSmall = ctx->chainTable;
     U32  const hBitsS = ctx->appliedParams.cParams.chainLog;
     seqStore_t* seqStorePtr = &(ctx->seqStore);
     const BYTE* const base = ctx->base;
     const BYTE* const dictBase = ctx->dictBase;
     const BYTE* const istart = (const BYTE*)src;
     const BYTE* ip = istart;
     const BYTE* anchor = istart;
     const U32   lowestIndex = ctx->lowLimit;
     const BYTE* const dictStart = dictBase + lowestIndex;
     const U32   dictLimit = ctx->dictLimit;
     const BYTE* const lowPrefixPtr = base + dictLimit;
     const BYTE* const dictEnd = dictBase + dictLimit;
     const BYTE* const iend = istart + srcSize;
     const BYTE* const ilimit = iend - 8;
     U32 offset_1=seqStorePtr->rep[0], offset_2=seqStorePtr->rep[1];
 
     /* Search Loop */
     while (ip < ilimit) {  /* < instead of <=, because (ip+1) */
         const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls);
         const U32 matchIndex = hashSmall[hSmall];
         const BYTE* matchBase = matchIndex < dictLimit ? dictBase : base;
         const BYTE* match = matchBase + matchIndex;
 
         const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8);
         const U32 matchLongIndex = hashLong[hLong];
         const BYTE* matchLongBase = matchLongIndex < dictLimit ? dictBase : base;
         const BYTE* matchLong = matchLongBase + matchLongIndex;
 
         const U32 current = (U32)(ip-base);
         const U32 repIndex = current + 1 - offset_1;   /* offset_1 expected <= current +1 */
         const BYTE* repBase = repIndex < dictLimit ? dictBase : base;
         const BYTE* repMatch = repBase + repIndex;
         size_t mLength;
         hashSmall[hSmall] = hashLong[hLong] = current;   /* update hash table */
 
         if ( (((U32)((dictLimit-1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > lowestIndex))
            && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
             const BYTE* repMatchEnd = repIndex < dictLimit ? dictEnd : iend;
             mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, lowPrefixPtr) + 4;
             ip++;
             ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, 0, mLength-MINMATCH);
         } else {
             if ((matchLongIndex > lowestIndex) && (MEM_read64(matchLong) == MEM_read64(ip))) {
                 const BYTE* matchEnd = matchLongIndex < dictLimit ? dictEnd : iend;
                 const BYTE* lowMatchPtr = matchLongIndex < dictLimit ? dictStart : lowPrefixPtr;
                 U32 offset;
                 mLength = ZSTD_count_2segments(ip+8, matchLong+8, iend, matchEnd, lowPrefixPtr) + 8;
                 offset = current - matchLongIndex;
                 while (((ip>anchor) & (matchLong>lowMatchPtr)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; }   /* catch up */
                 offset_2 = offset_1;
                 offset_1 = offset;
                 ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
 
             } else if ((matchIndex > lowestIndex) && (MEM_read32(match) == MEM_read32(ip))) {
                 size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
                 U32 const matchIndex3 = hashLong[h3];
                 const BYTE* const match3Base = matchIndex3 < dictLimit ? dictBase : base;
                 const BYTE* match3 = match3Base + matchIndex3;
                 U32 offset;
                 hashLong[h3] = current + 1;
                 if ( (matchIndex3 > lowestIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) {
                     const BYTE* matchEnd = matchIndex3 < dictLimit ? dictEnd : iend;
                     const BYTE* lowMatchPtr = matchIndex3 < dictLimit ? dictStart : lowPrefixPtr;
                     mLength = ZSTD_count_2segments(ip+9, match3+8, iend, matchEnd, lowPrefixPtr) + 8;
                     ip++;
                     offset = current+1 - matchIndex3;
                     while (((ip>anchor) & (match3>lowMatchPtr)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */
                 } else {
                     const BYTE* matchEnd = matchIndex < dictLimit ? dictEnd : iend;
                     const BYTE* lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr;
                     mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, lowPrefixPtr) + 4;
                     offset = current - matchIndex;
                     while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; }   /* catch up */
                 }
                 offset_2 = offset_1;
                 offset_1 = offset;
                 ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
 
             } else {
                 ip += ((ip-anchor) >> g_searchStrength) + 1;
                 continue;
         }   }
 
         /* found a match : store it */
         ip += mLength;
         anchor = ip;
 
         if (ip <= ilimit) {
             /* Fill Table */
             hashSmall[ZSTD_hashPtr(base+current+2, hBitsS, mls)] = current+2;
             hashLong[ZSTD_hashPtr(base+current+2, hBitsL, 8)] = current+2;
             hashSmall[ZSTD_hashPtr(ip-2, hBitsS, mls)] = (U32)(ip-2-base);
             hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
             /* check immediate repcode */
             while (ip <= ilimit) {
                 U32 const current2 = (U32)(ip-base);
                 U32 const repIndex2 = current2 - offset_2;
                 const BYTE* repMatch2 = repIndex2 < dictLimit ? dictBase + repIndex2 : base + repIndex2;
                 if ( (((U32)((dictLimit-1) - repIndex2) >= 3) & (repIndex2 > lowestIndex))  /* intentional overflow */
                    && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
                     const BYTE* const repEnd2 = repIndex2 < dictLimit ? dictEnd : iend;
                     size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, lowPrefixPtr) + 4;
                     U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset;   /* swap offset_2 <=> offset_1 */
                     ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2-MINMATCH);
                     hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2;
                     hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2;
                     ip += repLength2;
                     anchor = ip;
                     continue;
                 }
                 break;
     }   }   }
 
     /* save reps for next block */
     seqStorePtr->repToConfirm[0] = offset_1; seqStorePtr->repToConfirm[1] = offset_2;
 
     /* Return the last literals size */
     return iend - anchor;
 }
 
 
 size_t ZSTD_compressBlock_doubleFast_extDict(ZSTD_CCtx* ctx,
                          const void* src, size_t srcSize)
 {
     U32 const mls = ctx->appliedParams.cParams.searchLength;
     switch(mls)
     {
     default: /* includes case 3 */
     case 4 :
         return ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 4);
     case 5 :
         return ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 5);
     case 6 :
         return ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 6);
     case 7 :
         return ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 7);
     }
 }
Index: head/sys/contrib/zstd/lib/compress/zstd_double_fast.h
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_double_fast.h	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_double_fast.h	(revision 330894)
@@ -1,28 +1,29 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 #ifndef ZSTD_DOUBLE_FAST_H
 #define ZSTD_DOUBLE_FAST_H
 
-#include "zstd_compress.h"
-
 #if defined (__cplusplus)
 extern "C" {
 #endif
+
+#include "mem.h"      /* U32 */
+#include "zstd.h"     /* ZSTD_CCtx, size_t */
 
 void ZSTD_fillDoubleHashTable(ZSTD_CCtx* cctx, const void* end, const U32 mls);
 size_t ZSTD_compressBlock_doubleFast(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_doubleFast_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif /* ZSTD_DOUBLE_FAST_H */
Index: head/sys/contrib/zstd/lib/compress/zstd_fast.c
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_fast.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_fast.c	(revision 330894)
@@ -1,242 +1,243 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
+#include "zstd_compress_internal.h"
 #include "zstd_fast.h"
 
 
 void ZSTD_fillHashTable (ZSTD_CCtx* zc, const void* end, const U32 mls)
 {
     U32* const hashTable = zc->hashTable;
     U32  const hBits = zc->appliedParams.cParams.hashLog;
     const BYTE* const base = zc->base;
     const BYTE* ip = base + zc->nextToUpdate;
     const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
     const size_t fastHashFillStep = 3;
 
     while(ip <= iend) {
         hashTable[ZSTD_hashPtr(ip, hBits, mls)] = (U32)(ip - base);
         ip += fastHashFillStep;
     }
 }
 
 
 FORCE_INLINE_TEMPLATE
 size_t ZSTD_compressBlock_fast_generic(ZSTD_CCtx* cctx,
                                  const void* src, size_t srcSize,
                                  const U32 mls)
 {
     U32* const hashTable = cctx->hashTable;
     U32  const hBits = cctx->appliedParams.cParams.hashLog;
     seqStore_t* seqStorePtr = &(cctx->seqStore);
     const BYTE* const base = cctx->base;
     const BYTE* const istart = (const BYTE*)src;
     const BYTE* ip = istart;
     const BYTE* anchor = istart;
     const U32   lowestIndex = cctx->dictLimit;
     const BYTE* const lowest = base + lowestIndex;
     const BYTE* const iend = istart + srcSize;
     const BYTE* const ilimit = iend - HASH_READ_SIZE;
     U32 offset_1=seqStorePtr->rep[0], offset_2=seqStorePtr->rep[1];
     U32 offsetSaved = 0;
 
     /* init */
     ip += (ip==lowest);
     {   U32 const maxRep = (U32)(ip-lowest);
         if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
         if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
     }
 
     /* Main Search Loop */
     while (ip < ilimit) {   /* < instead of <=, because repcode check at (ip+1) */
         size_t mLength;
         size_t const h = ZSTD_hashPtr(ip, hBits, mls);
         U32 const current = (U32)(ip-base);
         U32 const matchIndex = hashTable[h];
         const BYTE* match = base + matchIndex;
         hashTable[h] = current;   /* update hash table */
 
         if ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))) {
             mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
             ip++;
             ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, 0, mLength-MINMATCH);
         } else {
             U32 offset;
             if ( (matchIndex <= lowestIndex) || (MEM_read32(match) != MEM_read32(ip)) ) {
                 ip += ((ip-anchor) >> g_searchStrength) + 1;
                 continue;
             }
             mLength = ZSTD_count(ip+4, match+4, iend) + 4;
             offset = (U32)(ip-match);
             while (((ip>anchor) & (match>lowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
             offset_2 = offset_1;
             offset_1 = offset;
 
             ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
         }
 
         /* match found */
         ip += mLength;
         anchor = ip;
 
         if (ip <= ilimit) {
             /* Fill Table */
             hashTable[ZSTD_hashPtr(base+current+2, hBits, mls)] = current+2;  /* here because current+2 could be > iend-8 */
             hashTable[ZSTD_hashPtr(ip-2, hBits, mls)] = (U32)(ip-2-base);
             /* check immediate repcode */
             while ( (ip <= ilimit)
                  && ( (offset_2>0)
                  & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
                 /* store sequence */
                 size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
                 { U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; }  /* swap offset_2 <=> offset_1 */
                 hashTable[ZSTD_hashPtr(ip, hBits, mls)] = (U32)(ip-base);
                 ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength-MINMATCH);
                 ip += rLength;
                 anchor = ip;
                 continue;   /* faster when present ... (?) */
     }   }   }
 
     /* save reps for next block */
     seqStorePtr->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved;
     seqStorePtr->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved;
 
     /* Return the last literals size */
     return iend - anchor;
 }
 
 
 size_t ZSTD_compressBlock_fast(ZSTD_CCtx* ctx,
                        const void* src, size_t srcSize)
 {
     const U32 mls = ctx->appliedParams.cParams.searchLength;
     switch(mls)
     {
     default: /* includes case 3 */
     case 4 :
         return ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 4);
     case 5 :
         return ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 5);
     case 6 :
         return ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 6);
     case 7 :
         return ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 7);
     }
 }
 
 
 static size_t ZSTD_compressBlock_fast_extDict_generic(ZSTD_CCtx* ctx,
                                  const void* src, size_t srcSize,
                                  const U32 mls)
 {
     U32* hashTable = ctx->hashTable;
     const U32 hBits = ctx->appliedParams.cParams.hashLog;
     seqStore_t* seqStorePtr = &(ctx->seqStore);
     const BYTE* const base = ctx->base;
     const BYTE* const dictBase = ctx->dictBase;
     const BYTE* const istart = (const BYTE*)src;
     const BYTE* ip = istart;
     const BYTE* anchor = istart;
     const U32   lowestIndex = ctx->lowLimit;
     const BYTE* const dictStart = dictBase + lowestIndex;
     const U32   dictLimit = ctx->dictLimit;
     const BYTE* const lowPrefixPtr = base + dictLimit;
     const BYTE* const dictEnd = dictBase + dictLimit;
     const BYTE* const iend = istart + srcSize;
     const BYTE* const ilimit = iend - 8;
     U32 offset_1=seqStorePtr->rep[0], offset_2=seqStorePtr->rep[1];
 
     /* Search Loop */
     while (ip < ilimit) {  /* < instead of <=, because (ip+1) */
         const size_t h = ZSTD_hashPtr(ip, hBits, mls);
         const U32 matchIndex = hashTable[h];
         const BYTE* matchBase = matchIndex < dictLimit ? dictBase : base;
         const BYTE* match = matchBase + matchIndex;
         const U32 current = (U32)(ip-base);
         const U32 repIndex = current + 1 - offset_1;   /* offset_1 expected <= current +1 */
         const BYTE* repBase = repIndex < dictLimit ? dictBase : base;
         const BYTE* repMatch = repBase + repIndex;
         size_t mLength;
         hashTable[h] = current;   /* update hash table */
 
         if ( (((U32)((dictLimit-1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > lowestIndex))
            && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
             const BYTE* repMatchEnd = repIndex < dictLimit ? dictEnd : iend;
             mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, lowPrefixPtr) + 4;
             ip++;
             ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, 0, mLength-MINMATCH);
         } else {
             if ( (matchIndex < lowestIndex) ||
                  (MEM_read32(match) != MEM_read32(ip)) ) {
                 ip += ((ip-anchor) >> g_searchStrength) + 1;
                 continue;
             }
             {   const BYTE* matchEnd = matchIndex < dictLimit ? dictEnd : iend;
                 const BYTE* lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr;
                 U32 offset;
                 mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, lowPrefixPtr) + 4;
                 while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; }   /* catch up */
                 offset = current - matchIndex;
                 offset_2 = offset_1;
                 offset_1 = offset;
                 ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
         }   }
 
         /* found a match : store it */
         ip += mLength;
         anchor = ip;
 
         if (ip <= ilimit) {
             /* Fill Table */
             hashTable[ZSTD_hashPtr(base+current+2, hBits, mls)] = current+2;
             hashTable[ZSTD_hashPtr(ip-2, hBits, mls)] = (U32)(ip-2-base);
             /* check immediate repcode */
             while (ip <= ilimit) {
                 U32 const current2 = (U32)(ip-base);
                 U32 const repIndex2 = current2 - offset_2;
                 const BYTE* repMatch2 = repIndex2 < dictLimit ? dictBase + repIndex2 : base + repIndex2;
                 if ( (((U32)((dictLimit-1) - repIndex2) >= 3) & (repIndex2 > lowestIndex))  /* intentional overflow */
                    && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
                     const BYTE* const repEnd2 = repIndex2 < dictLimit ? dictEnd : iend;
                     size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, lowPrefixPtr) + 4;
                     U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset;   /* swap offset_2 <=> offset_1 */
                     ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2-MINMATCH);
                     hashTable[ZSTD_hashPtr(ip, hBits, mls)] = current2;
                     ip += repLength2;
                     anchor = ip;
                     continue;
                 }
                 break;
     }   }   }
 
     /* save reps for next block */
     seqStorePtr->repToConfirm[0] = offset_1; seqStorePtr->repToConfirm[1] = offset_2;
 
     /* Return the last literals size */
     return iend - anchor;
 }
 
 
 size_t ZSTD_compressBlock_fast_extDict(ZSTD_CCtx* ctx,
                          const void* src, size_t srcSize)
 {
     U32 const mls = ctx->appliedParams.cParams.searchLength;
     switch(mls)
     {
     default: /* includes case 3 */
     case 4 :
         return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 4);
     case 5 :
         return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 5);
     case 6 :
         return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 6);
     case 7 :
         return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 7);
     }
 }
Index: head/sys/contrib/zstd/lib/compress/zstd_fast.h
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_fast.h	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_fast.h	(revision 330894)
@@ -1,30 +1,31 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 #ifndef ZSTD_FAST_H
 #define ZSTD_FAST_H
 
-#include "zstd_compress.h"
-
 #if defined (__cplusplus)
 extern "C" {
 #endif
+
+#include "mem.h"      /* U32 */
+#include "zstd.h"     /* ZSTD_CCtx, size_t */
 
 void ZSTD_fillHashTable(ZSTD_CCtx* zc, const void* end, const U32 mls);
 size_t ZSTD_compressBlock_fast(ZSTD_CCtx* ctx,
                          const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_fast_extDict(ZSTD_CCtx* ctx,
                          const void* src, size_t srcSize);
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif /* ZSTD_FAST_H */
Index: head/sys/contrib/zstd/lib/compress/zstd_lazy.c
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_lazy.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_lazy.c	(revision 330894)
@@ -1,749 +1,765 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
+#include "zstd_compress_internal.h"
 #include "zstd_lazy.h"
 
 
 /*-*************************************
 *  Binary Tree search
 ***************************************/
 /** ZSTD_insertBt1() : add one or multiple positions to tree.
-*   ip : assumed <= iend-8 .
-*   @return : nb of positions added */
-static U32 ZSTD_insertBt1(ZSTD_CCtx* zc, const BYTE* const ip, const U32 mls, const BYTE* const iend, U32 nbCompares,
-                          U32 extDict)
+ *  ip : assumed <= iend-8 .
+ * @return : nb of positions added */
+static U32 ZSTD_insertBt1(ZSTD_CCtx* zc,
+                const BYTE* const ip, const BYTE* const iend,
+                U32 nbCompares, U32 const mls, U32 const extDict)
 {
     U32*   const hashTable = zc->hashTable;
     U32    const hashLog = zc->appliedParams.cParams.hashLog;
     size_t const h  = ZSTD_hashPtr(ip, hashLog, mls);
     U32*   const bt = zc->chainTable;
     U32    const btLog  = zc->appliedParams.cParams.chainLog - 1;
     U32    const btMask = (1 << btLog) - 1;
     U32 matchIndex = hashTable[h];
     size_t commonLengthSmaller=0, commonLengthLarger=0;
     const BYTE* const base = zc->base;
     const BYTE* const dictBase = zc->dictBase;
     const U32 dictLimit = zc->dictLimit;
     const BYTE* const dictEnd = dictBase + dictLimit;
     const BYTE* const prefixStart = base + dictLimit;
     const BYTE* match;
     const U32 current = (U32)(ip-base);
     const U32 btLow = btMask >= current ? 0 : current - btMask;
     U32* smallerPtr = bt + 2*(current&btMask);
     U32* largerPtr  = smallerPtr + 1;
     U32 dummy32;   /* to be nullified at the end */
     U32 const windowLow = zc->lowLimit;
-    U32 matchEndIdx = current+8;
+    U32 matchEndIdx = current+8+1;
     size_t bestLength = 8;
 #ifdef ZSTD_C_PREDICT
     U32 predictedSmall = *(bt + 2*((current-1)&btMask) + 0);
     U32 predictedLarge = *(bt + 2*((current-1)&btMask) + 1);
     predictedSmall += (predictedSmall>0);
     predictedLarge += (predictedLarge>0);
 #endif /* ZSTD_C_PREDICT */
 
+    DEBUGLOG(8, "ZSTD_insertBt1 (%u)", current);
+
     assert(ip <= iend-8);   /* required for h calculation */
     hashTable[h] = current;   /* Update Hash Table */
 
     while (nbCompares-- && (matchIndex > windowLow)) {
         U32* const nextPtr = bt + 2*(matchIndex & btMask);
         size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
+        assert(matchIndex < current);
 
 #ifdef ZSTD_C_PREDICT   /* note : can create issues when hlog small <= 11 */
         const U32* predictPtr = bt + 2*((matchIndex-1) & btMask);   /* written this way, as bt is a roll buffer */
         if (matchIndex == predictedSmall) {
             /* no need to check length, result known */
             *smallerPtr = matchIndex;
             if (matchIndex <= btLow) { smallerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
             smallerPtr = nextPtr+1;               /* new "smaller" => larger of match */
             matchIndex = nextPtr[1];              /* new matchIndex larger than previous (closer to current) */
             predictedSmall = predictPtr[1] + (predictPtr[1]>0);
             continue;
         }
         if (matchIndex == predictedLarge) {
             *largerPtr = matchIndex;
             if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
             largerPtr = nextPtr;
             matchIndex = nextPtr[0];
             predictedLarge = predictPtr[0] + (predictPtr[0]>0);
             continue;
         }
 #endif
+
         if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
+            assert(matchIndex+matchLength >= dictLimit);   /* might be wrong if extDict is incorrectly set to 0 */
             match = base + matchIndex;
-            if (match[matchLength] == ip[matchLength])
-                matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1;
+            matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
         } else {
             match = dictBase + matchIndex;
             matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
             if (matchIndex+matchLength >= dictLimit)
                 match = base + matchIndex;   /* to prepare for next usage of match[matchLength] */
         }
 
         if (matchLength > bestLength) {
             bestLength = matchLength;
             if (matchLength > matchEndIdx - matchIndex)
                 matchEndIdx = matchIndex + (U32)matchLength;
         }
 
-        if (ip+matchLength == iend)   /* equal : no way to know if inf or sup */
+        if (ip+matchLength == iend) {   /* equal : no way to know if inf or sup */
             break;   /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */
+        }
 
         if (match[matchLength] < ip[matchLength]) {  /* necessarily within buffer */
-            /* match+1 is smaller than current */
+            /* match is smaller than current */
             *smallerPtr = matchIndex;             /* update smaller idx */
             commonLengthSmaller = matchLength;    /* all smaller will now have at least this guaranteed common length */
             if (matchIndex <= btLow) { smallerPtr=&dummy32; break; }   /* beyond tree size, stop searching */
-            smallerPtr = nextPtr+1;               /* new "smaller" => larger of match */
-            matchIndex = nextPtr[1];              /* new matchIndex larger than previous (closer to current) */
+            smallerPtr = nextPtr+1;               /* new "candidate" => larger than match, which was smaller than target */
+            matchIndex = nextPtr[1];              /* new matchIndex, larger than previous and closer to current */
         } else {
             /* match is larger than current */
             *largerPtr = matchIndex;
             commonLengthLarger = matchLength;
             if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop searching */
             largerPtr = nextPtr;
             matchIndex = nextPtr[0];
     }   }
 
     *smallerPtr = *largerPtr = 0;
     if (bestLength > 384) return MIN(192, (U32)(bestLength - 384));   /* speed optimization */
-    if (matchEndIdx > current + 8) return matchEndIdx - (current + 8);
-    return 1;
+    assert(matchEndIdx > current + 8);
+    return matchEndIdx - (current + 8);
 }
 
+FORCE_INLINE_TEMPLATE
+void ZSTD_updateTree_internal(ZSTD_CCtx* zc,
+                const BYTE* const ip, const BYTE* const iend,
+                const U32 nbCompares, const U32 mls, const U32 extDict)
+{
+    const BYTE* const base = zc->base;
+    U32 const target = (U32)(ip - base);
+    U32 idx = zc->nextToUpdate;
+    DEBUGLOG(7, "ZSTD_updateTree_internal, from %u to %u  (extDict:%u)",
+                idx, target, extDict);
 
+    while(idx < target)
+        idx += ZSTD_insertBt1(zc, base+idx, iend, nbCompares, mls, extDict);
+    zc->nextToUpdate = target;
+}
+
+void ZSTD_updateTree(ZSTD_CCtx* zc,
+                const BYTE* const ip, const BYTE* const iend,
+                const U32 nbCompares, const U32 mls)
+{
+    ZSTD_updateTree_internal(zc, ip, iend, nbCompares, mls, 0 /*extDict*/);
+}
+
+void ZSTD_updateTree_extDict(ZSTD_CCtx* zc,
+                const BYTE* const ip, const BYTE* const iend,
+                const U32 nbCompares, const U32 mls)
+{
+    ZSTD_updateTree_internal(zc, ip, iend, nbCompares, mls, 1 /*extDict*/);
+}
+
+
 static size_t ZSTD_insertBtAndFindBestMatch (
                         ZSTD_CCtx* zc,
                         const BYTE* const ip, const BYTE* const iend,
                         size_t* offsetPtr,
                         U32 nbCompares, const U32 mls,
                         U32 extDict)
 {
     U32*   const hashTable = zc->hashTable;
     U32    const hashLog = zc->appliedParams.cParams.hashLog;
     size_t const h  = ZSTD_hashPtr(ip, hashLog, mls);
     U32*   const bt = zc->chainTable;
     U32    const btLog  = zc->appliedParams.cParams.chainLog - 1;
     U32    const btMask = (1 << btLog) - 1;
     U32 matchIndex  = hashTable[h];
     size_t commonLengthSmaller=0, commonLengthLarger=0;
     const BYTE* const base = zc->base;
     const BYTE* const dictBase = zc->dictBase;
     const U32 dictLimit = zc->dictLimit;
     const BYTE* const dictEnd = dictBase + dictLimit;
     const BYTE* const prefixStart = base + dictLimit;
     const U32 current = (U32)(ip-base);
     const U32 btLow = btMask >= current ? 0 : current - btMask;
     const U32 windowLow = zc->lowLimit;
     U32* smallerPtr = bt + 2*(current&btMask);
     U32* largerPtr  = bt + 2*(current&btMask) + 1;
-    U32 matchEndIdx = current+8;
+    U32 matchEndIdx = current+8+1;
     U32 dummy32;   /* to be nullified at the end */
     size_t bestLength = 0;
 
     assert(ip <= iend-8);   /* required for h calculation */
     hashTable[h] = current;   /* Update Hash Table */
 
     while (nbCompares-- && (matchIndex > windowLow)) {
         U32* const nextPtr = bt + 2*(matchIndex & btMask);
         size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
         const BYTE* match;
 
         if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
             match = base + matchIndex;
-            if (match[matchLength] == ip[matchLength])
-                matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1;
+            matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
         } else {
             match = dictBase + matchIndex;
             matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
             if (matchIndex+matchLength >= dictLimit)
                 match = base + matchIndex;   /* to prepare for next usage of match[matchLength] */
         }
 
         if (matchLength > bestLength) {
             if (matchLength > matchEndIdx - matchIndex)
                 matchEndIdx = matchIndex + (U32)matchLength;
             if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) )
                 bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + current - matchIndex;
-            if (ip+matchLength == iend)   /* equal : no way to know if inf or sup */
+            if (ip+matchLength == iend) {   /* equal : no way to know if inf or sup */
                 break;   /* drop, to guarantee consistency (miss a little bit of compression) */
+            }
         }
 
         if (match[matchLength] < ip[matchLength]) {
             /* match is smaller than current */
             *smallerPtr = matchIndex;             /* update smaller idx */
             commonLengthSmaller = matchLength;    /* all smaller will now have at least this guaranteed common length */
             if (matchIndex <= btLow) { smallerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
             smallerPtr = nextPtr+1;               /* new "smaller" => larger of match */
             matchIndex = nextPtr[1];              /* new matchIndex larger than previous (closer to current) */
         } else {
             /* match is larger than current */
             *largerPtr = matchIndex;
             commonLengthLarger = matchLength;
             if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
             largerPtr = nextPtr;
             matchIndex = nextPtr[0];
     }   }
 
     *smallerPtr = *largerPtr = 0;
 
-    zc->nextToUpdate = (matchEndIdx > current + 8) ? matchEndIdx - 8 : current+1;
+    assert(matchEndIdx > current+8);
+    zc->nextToUpdate = matchEndIdx - 8;   /* skip repetitive patterns */
     return bestLength;
 }
 
 
-void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls)
-{
-    const BYTE* const base = zc->base;
-    const U32 target = (U32)(ip - base);
-    U32 idx = zc->nextToUpdate;
-
-    while(idx < target)
-        idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 0);
-}
-
 /** ZSTD_BtFindBestMatch() : Tree updater, providing best match */
 static size_t ZSTD_BtFindBestMatch (
                         ZSTD_CCtx* zc,
                         const BYTE* const ip, const BYTE* const iLimit,
                         size_t* offsetPtr,
                         const U32 maxNbAttempts, const U32 mls)
 {
     if (ip < zc->base + zc->nextToUpdate) return 0;   /* skipped area */
     ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
     return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 0);
 }
 
 
 static size_t ZSTD_BtFindBestMatch_selectMLS (
                         ZSTD_CCtx* zc,   /* Index table will be updated */
                         const BYTE* ip, const BYTE* const iLimit,
                         size_t* offsetPtr,
                         const U32 maxNbAttempts, const U32 matchLengthSearch)
 {
     switch(matchLengthSearch)
     {
     default : /* includes case 3 */
     case 4 : return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4);
     case 5 : return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5);
     case 7 :
     case 6 : return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6);
     }
 }
 
 
-void ZSTD_updateTree_extDict(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls)
-{
-    const BYTE* const base = zc->base;
-    const U32 target = (U32)(ip - base);
-    U32 idx = zc->nextToUpdate;
-
-    while (idx < target) idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 1);
-}
-
-
 /** Tree updater, providing best match */
 static size_t ZSTD_BtFindBestMatch_extDict (
                         ZSTD_CCtx* zc,
                         const BYTE* const ip, const BYTE* const iLimit,
                         size_t* offsetPtr,
                         const U32 maxNbAttempts, const U32 mls)
 {
     if (ip < zc->base + zc->nextToUpdate) return 0;   /* skipped area */
     ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
     return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 1);
 }
 
 
 static size_t ZSTD_BtFindBestMatch_selectMLS_extDict (
                         ZSTD_CCtx* zc,   /* Index table will be updated */
                         const BYTE* ip, const BYTE* const iLimit,
                         size_t* offsetPtr,
                         const U32 maxNbAttempts, const U32 matchLengthSearch)
 {
     switch(matchLengthSearch)
     {
     default : /* includes case 3 */
     case 4 : return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4);
     case 5 : return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5);
     case 7 :
     case 6 : return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6);
     }
 }
 
 
 
 /* *********************************
 *  Hash Chain
 ***********************************/
 #define NEXT_IN_CHAIN(d, mask)   chainTable[(d) & mask]
 
 /* Update chains up to ip (excluded)
    Assumption : always within prefix (i.e. not within extDict) */
 U32 ZSTD_insertAndFindFirstIndex (ZSTD_CCtx* zc, const BYTE* ip, U32 mls)
 {
     U32* const hashTable  = zc->hashTable;
     const U32 hashLog = zc->appliedParams.cParams.hashLog;
     U32* const chainTable = zc->chainTable;
     const U32 chainMask = (1 << zc->appliedParams.cParams.chainLog) - 1;
     const BYTE* const base = zc->base;
     const U32 target = (U32)(ip - base);
     U32 idx = zc->nextToUpdate;
 
     while(idx < target) { /* catch up */
         size_t const h = ZSTD_hashPtr(base+idx, hashLog, mls);
         NEXT_IN_CHAIN(idx, chainMask) = hashTable[h];
         hashTable[h] = idx;
         idx++;
     }
 
     zc->nextToUpdate = target;
     return hashTable[ZSTD_hashPtr(ip, hashLog, mls)];
 }
 
 
 /* inlining is important to hardwire a hot branch (template emulation) */
 FORCE_INLINE_TEMPLATE
 size_t ZSTD_HcFindBestMatch_generic (
                         ZSTD_CCtx* zc,   /* Index table will be updated */
                         const BYTE* const ip, const BYTE* const iLimit,
                         size_t* offsetPtr,
                         const U32 maxNbAttempts, const U32 mls, const U32 extDict)
 {
     U32* const chainTable = zc->chainTable;
     const U32 chainSize = (1 << zc->appliedParams.cParams.chainLog);
     const U32 chainMask = chainSize-1;
     const BYTE* const base = zc->base;
     const BYTE* const dictBase = zc->dictBase;
     const U32 dictLimit = zc->dictLimit;
     const BYTE* const prefixStart = base + dictLimit;
     const BYTE* const dictEnd = dictBase + dictLimit;
     const U32 lowLimit = zc->lowLimit;
     const U32 current = (U32)(ip-base);
     const U32 minChain = current > chainSize ? current - chainSize : 0;
     int nbAttempts=maxNbAttempts;
     size_t ml=4-1;
 
     /* HC4 match finder */
     U32 matchIndex = ZSTD_insertAndFindFirstIndex (zc, ip, mls);
 
     for ( ; (matchIndex>lowLimit) & (nbAttempts>0) ; nbAttempts--) {
-        const BYTE* match;
         size_t currentMl=0;
         if ((!extDict) || matchIndex >= dictLimit) {
-            match = base + matchIndex;
+            const BYTE* const match = base + matchIndex;
             if (match[ml] == ip[ml])   /* potentially better */
                 currentMl = ZSTD_count(ip, match, iLimit);
         } else {
-            match = dictBase + matchIndex;
+            const BYTE* const match = dictBase + matchIndex;
+            assert(match+4 <= dictEnd);
             if (MEM_read32(match) == MEM_read32(ip))   /* assumption : matchIndex <= dictLimit-4 (by table construction) */
                 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4;
         }
 
         /* save best solution */
         if (currentMl > ml) {
             ml = currentMl;
             *offsetPtr = current - matchIndex + ZSTD_REP_MOVE;
             if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
         }
 
         if (matchIndex <= minChain) break;
         matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask);
     }
 
     return ml;
 }
 
 
 FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (
                         ZSTD_CCtx* zc,
                         const BYTE* ip, const BYTE* const iLimit,
                         size_t* offsetPtr,
                         const U32 maxNbAttempts, const U32 matchLengthSearch)
 {
     switch(matchLengthSearch)
     {
     default : /* includes case 3 */
     case 4 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4, 0);
     case 5 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5, 0);
     case 7 :
     case 6 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6, 0);
     }
 }
 
 
 FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
-                        ZSTD_CCtx* zc,
+                        ZSTD_CCtx* const zc,
                         const BYTE* ip, const BYTE* const iLimit,
-                        size_t* offsetPtr,
-                        const U32 maxNbAttempts, const U32 matchLengthSearch)
+                        size_t* const offsetPtr,
+                        U32 const maxNbAttempts, U32 const matchLengthSearch)
 {
     switch(matchLengthSearch)
     {
     default : /* includes case 3 */
     case 4 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4, 1);
     case 5 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5, 1);
     case 7 :
     case 6 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6, 1);
     }
 }
 
 
 /* *******************************
 *  Common parser - lazy strategy
 *********************************/
 FORCE_INLINE_TEMPLATE
 size_t ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
                                        const void* src, size_t srcSize,
                                        const U32 searchMethod, const U32 depth)
 {
     seqStore_t* seqStorePtr = &(ctx->seqStore);
     const BYTE* const istart = (const BYTE*)src;
     const BYTE* ip = istart;
     const BYTE* anchor = istart;
     const BYTE* const iend = istart + srcSize;
     const BYTE* const ilimit = iend - 8;
     const BYTE* const base = ctx->base + ctx->dictLimit;
 
     U32 const maxSearches = 1 << ctx->appliedParams.cParams.searchLog;
     U32 const mls = ctx->appliedParams.cParams.searchLength;
 
     typedef size_t (*searchMax_f)(ZSTD_CCtx* zc, const BYTE* ip, const BYTE* iLimit,
                         size_t* offsetPtr,
                         U32 maxNbAttempts, U32 matchLengthSearch);
     searchMax_f const searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS;
     U32 offset_1 = seqStorePtr->rep[0], offset_2 = seqStorePtr->rep[1], savedOffset=0;
 
     /* init */
     ip += (ip==base);
     ctx->nextToUpdate3 = ctx->nextToUpdate;
     {   U32 const maxRep = (U32)(ip-base);
         if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0;
         if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0;
     }
 
     /* Match Loop */
     while (ip < ilimit) {
         size_t matchLength=0;
         size_t offset=0;
         const BYTE* start=ip+1;
 
         /* check repCode */
         if ((offset_1>0) & (MEM_read32(ip+1) == MEM_read32(ip+1 - offset_1))) {
             /* repcode : we take it */
             matchLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
             if (depth==0) goto _storeSequence;
         }
 
         /* first search (depth 0) */
         {   size_t offsetFound = 99999999;
             size_t const ml2 = searchMax(ctx, ip, iend, &offsetFound, maxSearches, mls);
             if (ml2 > matchLength)
                 matchLength = ml2, start = ip, offset=offsetFound;
         }
 
         if (matchLength < 4) {
             ip += ((ip-anchor) >> g_searchStrength) + 1;   /* jump faster over incompressible sections */
             continue;
         }
 
         /* let's try to find a better solution */
         if (depth>=1)
         while (ip0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
                 size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4;
                 int const gain2 = (int)(mlRep * 3);
                 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1);
                 if ((mlRep >= 4) && (gain2 > gain1))
                     matchLength = mlRep, offset = 0, start = ip;
             }
             {   size_t offset2=99999999;
                 size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
                 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4);
                 if ((ml2 >= 4) && (gain2 > gain1)) {
                     matchLength = ml2, offset = offset2, start = ip;
                     continue;   /* search a better one */
             }   }
 
             /* let's find an even better one */
             if ((depth==2) && (ip0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
                     size_t const ml2 = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4;
                     int const gain2 = (int)(ml2 * 4);
                     int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
                     if ((ml2 >= 4) && (gain2 > gain1))
                         matchLength = ml2, offset = 0, start = ip;
                 }
                 {   size_t offset2=99999999;
                     size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
                     int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                     int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7);
                     if ((ml2 >= 4) && (gain2 > gain1)) {
                         matchLength = ml2, offset = offset2, start = ip;
                         continue;
             }   }   }
             break;  /* nothing found : store previous solution */
         }
 
         /* NOTE:
          * start[-offset+ZSTD_REP_MOVE-1] is undefined behavior.
          * (-offset+ZSTD_REP_MOVE-1) is unsigned, and is added to start, which
          * overflows the pointer, which is undefined behavior.
          */
         /* catch up */
         if (offset) {
-            while ( (start > anchor)
-                 && (start > base+offset-ZSTD_REP_MOVE)
-                 && (start[-1] == (start-offset+ZSTD_REP_MOVE)[-1]) )  /* only search for offset within prefix */
+            while ( ((start > anchor) & (start - (offset-ZSTD_REP_MOVE) > base))
+                 && (start[-1] == (start-(offset-ZSTD_REP_MOVE))[-1]) )  /* only search for offset within prefix */
                 { start--; matchLength++; }
             offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE);
         }
         /* store sequence */
 _storeSequence:
         {   size_t const litLength = start - anchor;
             ZSTD_storeSeq(seqStorePtr, litLength, anchor, (U32)offset, matchLength-MINMATCH);
             anchor = ip = start + matchLength;
         }
 
         /* check immediate repcode */
-        while ( (ip <= ilimit)
-             && ((offset_2>0)
-             & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
+        while ( ((ip <= ilimit) & (offset_2>0))
+             && (MEM_read32(ip) == MEM_read32(ip - offset_2)) ) {
             /* store sequence */
             matchLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
             offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap repcodes */
             ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, matchLength-MINMATCH);
             ip += matchLength;
             anchor = ip;
             continue;   /* faster when present ... (?) */
     }   }
 
     /* Save reps for next block */
     seqStorePtr->repToConfirm[0] = offset_1 ? offset_1 : savedOffset;
     seqStorePtr->repToConfirm[1] = offset_2 ? offset_2 : savedOffset;
 
     /* Return the last literals size */
     return iend - anchor;
 }
 
 
 size_t ZSTD_compressBlock_btlazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
     return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 1, 2);
 }
 
 size_t ZSTD_compressBlock_lazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
     return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 2);
 }
 
 size_t ZSTD_compressBlock_lazy(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
     return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 1);
 }
 
 size_t ZSTD_compressBlock_greedy(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
     return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 0);
 }
 
 
 FORCE_INLINE_TEMPLATE
 size_t ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
                                      const void* src, size_t srcSize,
                                      const U32 searchMethod, const U32 depth)
 {
     seqStore_t* seqStorePtr = &(ctx->seqStore);
     const BYTE* const istart = (const BYTE*)src;
     const BYTE* ip = istart;
     const BYTE* anchor = istart;
     const BYTE* const iend = istart + srcSize;
     const BYTE* const ilimit = iend - 8;
     const BYTE* const base = ctx->base;
     const U32 dictLimit = ctx->dictLimit;
     const U32 lowestIndex = ctx->lowLimit;
     const BYTE* const prefixStart = base + dictLimit;
     const BYTE* const dictBase = ctx->dictBase;
     const BYTE* const dictEnd  = dictBase + dictLimit;
     const BYTE* const dictStart  = dictBase + ctx->lowLimit;
 
     const U32 maxSearches = 1 << ctx->appliedParams.cParams.searchLog;
     const U32 mls = ctx->appliedParams.cParams.searchLength;
 
     typedef size_t (*searchMax_f)(ZSTD_CCtx* zc, const BYTE* ip, const BYTE* iLimit,
                         size_t* offsetPtr,
                         U32 maxNbAttempts, U32 matchLengthSearch);
     searchMax_f searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS_extDict : ZSTD_HcFindBestMatch_extDict_selectMLS;
 
     U32 offset_1 = seqStorePtr->rep[0], offset_2 = seqStorePtr->rep[1];
 
     /* init */
     ctx->nextToUpdate3 = ctx->nextToUpdate;
     ip += (ip == prefixStart);
 
     /* Match Loop */
     while (ip < ilimit) {
         size_t matchLength=0;
         size_t offset=0;
         const BYTE* start=ip+1;
         U32 current = (U32)(ip-base);
 
         /* check repCode */
         {   const U32 repIndex = (U32)(current+1 - offset_1);
             const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
             const BYTE* const repMatch = repBase + repIndex;
             if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > lowestIndex))   /* intentional overflow */
             if (MEM_read32(ip+1) == MEM_read32(repMatch)) {
                 /* repcode detected we should take it */
                 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
                 matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repEnd, prefixStart) + 4;
                 if (depth==0) goto _storeSequence;
         }   }
 
         /* first search (depth 0) */
         {   size_t offsetFound = 99999999;
             size_t const ml2 = searchMax(ctx, ip, iend, &offsetFound, maxSearches, mls);
             if (ml2 > matchLength)
                 matchLength = ml2, start = ip, offset=offsetFound;
         }
 
          if (matchLength < 4) {
             ip += ((ip-anchor) >> g_searchStrength) + 1;   /* jump faster over incompressible sections */
             continue;
         }
 
         /* let's try to find a better solution */
         if (depth>=1)
         while (ip= 3) & (repIndex > lowestIndex))  /* intentional overflow */
                 if (MEM_read32(ip) == MEM_read32(repMatch)) {
                     /* repcode detected */
                     const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
                     size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
                     int const gain2 = (int)(repLength * 3);
                     int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1);
                     if ((repLength >= 4) && (gain2 > gain1))
                         matchLength = repLength, offset = 0, start = ip;
             }   }
 
             /* search match, depth 1 */
             {   size_t offset2=99999999;
                 size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
                 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4);
                 if ((ml2 >= 4) && (gain2 > gain1)) {
                     matchLength = ml2, offset = offset2, start = ip;
                     continue;   /* search a better one */
             }   }
 
             /* let's find an even better one */
             if ((depth==2) && (ip= 3) & (repIndex > lowestIndex))  /* intentional overflow */
                     if (MEM_read32(ip) == MEM_read32(repMatch)) {
                         /* repcode detected */
                         const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
                         size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
                         int const gain2 = (int)(repLength * 4);
                         int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
                         if ((repLength >= 4) && (gain2 > gain1))
                             matchLength = repLength, offset = 0, start = ip;
                 }   }
 
                 /* search match, depth 2 */
                 {   size_t offset2=99999999;
                     size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
                     int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                     int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7);
                     if ((ml2 >= 4) && (gain2 > gain1)) {
                         matchLength = ml2, offset = offset2, start = ip;
                         continue;
             }   }   }
             break;  /* nothing found : store previous solution */
         }
 
         /* catch up */
         if (offset) {
             U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE));
             const BYTE* match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex;
             const BYTE* const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart;
             while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; }  /* catch up */
             offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE);
         }
 
         /* store sequence */
 _storeSequence:
         {   size_t const litLength = start - anchor;
             ZSTD_storeSeq(seqStorePtr, litLength, anchor, (U32)offset, matchLength-MINMATCH);
             anchor = ip = start + matchLength;
         }
 
         /* check immediate repcode */
         while (ip <= ilimit) {
             const U32 repIndex = (U32)((ip-base) - offset_2);
             const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
             const BYTE* const repMatch = repBase + repIndex;
             if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > lowestIndex))  /* intentional overflow */
             if (MEM_read32(ip) == MEM_read32(repMatch)) {
                 /* repcode detected we should take it */
                 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
                 matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
                 offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset;   /* swap offset history */
                 ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, matchLength-MINMATCH);
                 ip += matchLength;
                 anchor = ip;
                 continue;   /* faster when present ... (?) */
             }
             break;
     }   }
 
     /* Save reps for next block */
     seqStorePtr->repToConfirm[0] = offset_1; seqStorePtr->repToConfirm[1] = offset_2;
 
     /* Return the last literals size */
     return iend - anchor;
 }
 
 
 size_t ZSTD_compressBlock_greedy_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
     return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 0);
 }
 
 size_t ZSTD_compressBlock_lazy_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
     return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 1);
 }
 
 size_t ZSTD_compressBlock_lazy2_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
     return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 2);
 }
 
 size_t ZSTD_compressBlock_btlazy2_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
     return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 1, 2);
 }
Index: head/sys/contrib/zstd/lib/compress/zstd_lazy.h
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_lazy.h	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_lazy.h	(revision 330894)
@@ -1,38 +1,39 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 #ifndef ZSTD_LAZY_H
 #define ZSTD_LAZY_H
 
-#include "zstd_compress.h"
-
 #if defined (__cplusplus)
 extern "C" {
 #endif
+
+#include "mem.h"    /* U32 */
+#include "zstd.h"   /* ZSTD_CCtx, size_t */
 
 U32 ZSTD_insertAndFindFirstIndex (ZSTD_CCtx* zc, const BYTE* ip, U32 mls);
 void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls);
 void ZSTD_updateTree_extDict(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls);
 
 size_t ZSTD_compressBlock_btlazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_lazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_lazy(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_greedy(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 
 size_t ZSTD_compressBlock_greedy_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_lazy_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_lazy2_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_btlazy2_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif /* ZSTD_LAZY_H */
Index: head/sys/contrib/zstd/lib/compress/zstd_ldm.h
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_ldm.h	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_ldm.h	(revision 330894)
@@ -1,67 +1,68 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  */
 
 #ifndef ZSTD_LDM_H
 #define ZSTD_LDM_H
 
-#include "zstd_compress.h"
-
 #if defined (__cplusplus)
 extern "C" {
 #endif
+
+#include "zstd_compress_internal.h"   /* ldmParams_t, U32 */
+#include "zstd.h"   /* ZSTD_CCtx, size_t */
 
 /*-*************************************
 *  Long distance matching
 ***************************************/
 
 #define ZSTD_LDM_DEFAULT_WINDOW_LOG ZSTD_WINDOWLOG_DEFAULTMAX
 #define ZSTD_LDM_HASHEVERYLOG_NOTSET 9999
 
 /** ZSTD_compressBlock_ldm_generic() :
  *
  *  This is a block compressor intended for long distance matching.
  *
  *  The function searches for matches of length at least
  *  ldmParams.minMatchLength using a hash table in cctx->ldmState.
  *  Matches can be at a distance of up to cParams.windowLog.
  *
  *  Upon finding a match, the unmatched literals are compressed using a
  *  ZSTD_blockCompressor (depending on the strategy in the compression
  *  parameters), which stores the matched sequences. The "long distance"
  *  match is then stored with the remaining literals from the
  *  ZSTD_blockCompressor. */
 size_t ZSTD_compressBlock_ldm(ZSTD_CCtx* cctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_ldm_extDict(ZSTD_CCtx* ctx,
                                       const void* src, size_t srcSize);
 
 /** ZSTD_ldm_initializeParameters() :
  *  Initialize the long distance matching parameters to their default values. */
 size_t ZSTD_ldm_initializeParameters(ldmParams_t* params, U32 enableLdm);
 
 /** ZSTD_ldm_getTableSize() :
  *  Estimate the space needed for long distance matching tables. */
 size_t ZSTD_ldm_getTableSize(U32 hashLog, U32 bucketSizeLog);
 
 /** ZSTD_ldm_getTableSize() :
  *  Return prime8bytes^(minMatchLength-1) */
 U64 ZSTD_ldm_getHashPower(U32 minMatchLength);
 
 /** ZSTD_ldm_adjustParameters() :
  *  If the params->hashEveryLog is not set, set it to its default value based on
  *  windowLog and params->hashLog.
  *
  *  Ensures that params->bucketSizeLog is <= params->hashLog (setting it to
  *  params->hashLog if it is not). */
 void ZSTD_ldm_adjustParameters(ldmParams_t* params, U32 windowLog);
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif /* ZSTD_FAST_H */
Index: head/sys/contrib/zstd/lib/compress/zstd_opt.c
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_opt.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_opt.c	(revision 330894)
@@ -1,957 +1,785 @@
 /*
  * Copyright (c) 2016-present, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
+#include "zstd_compress_internal.h"
 #include "zstd_opt.h"
-#include "zstd_lazy.h"
+#include "zstd_lazy.h"   /* ZSTD_updateTree, ZSTD_updateTree_extDict */
 
 
-#define ZSTD_LITFREQ_ADD    2
-#define ZSTD_FREQ_DIV       4
-#define ZSTD_MAX_PRICE      (1<<30)
+#define ZSTD_LITFREQ_ADD    2   /* scaling factor for litFreq, so that frequencies adapt faster to new stats. Also used for matchSum (?) */
+#define ZSTD_FREQ_DIV       4   /* log factor when using previous stats to init next stats */
+#define ZSTD_MAX_PRICE     (1<<30)
 
+
 /*-*************************************
 *  Price functions for optimal parser
 ***************************************/
 static void ZSTD_setLog2Prices(optState_t* optPtr)
 {
-    optPtr->log2matchLengthSum = ZSTD_highbit32(optPtr->matchLengthSum+1);
-    optPtr->log2litLengthSum = ZSTD_highbit32(optPtr->litLengthSum+1);
     optPtr->log2litSum = ZSTD_highbit32(optPtr->litSum+1);
+    optPtr->log2litLengthSum = ZSTD_highbit32(optPtr->litLengthSum+1);
+    optPtr->log2matchLengthSum = ZSTD_highbit32(optPtr->matchLengthSum+1);
     optPtr->log2offCodeSum = ZSTD_highbit32(optPtr->offCodeSum+1);
-    optPtr->factor = 1 + ((optPtr->litSum>>5) / optPtr->litLengthSum) + ((optPtr->litSum<<1) / (optPtr->litSum + optPtr->matchSum));
 }
 
 
-static void ZSTD_rescaleFreqs(optState_t* optPtr, const BYTE* src, size_t srcSize)
+static void ZSTD_rescaleFreqs(optState_t* const optPtr,
+                              const BYTE* const src, size_t const srcSize)
 {
-    unsigned u;
-
-    optPtr->cachedLiterals = NULL;
-    optPtr->cachedPrice = optPtr->cachedLitLength = 0;
     optPtr->staticPrices = 0;
 
-    if (optPtr->litLengthSum == 0) {
+    if (optPtr->litLengthSum == 0) {  /* first init */
+        unsigned u;
         if (srcSize <= 1024) optPtr->staticPrices = 1;
 
         assert(optPtr->litFreq!=NULL);
         for (u=0; u<=MaxLit; u++)
             optPtr->litFreq[u] = 0;
         for (u=0; ulitFreq[src[u]]++;
-
         optPtr->litSum = 0;
-        optPtr->litLengthSum = MaxLL+1;
-        optPtr->matchLengthSum = MaxML+1;
-        optPtr->offCodeSum = (MaxOff+1);
-        optPtr->matchSum = (ZSTD_LITFREQ_ADD<litFreq[u] = 1 + (optPtr->litFreq[u]>>ZSTD_FREQ_DIV);
+            optPtr->litFreq[u] = 1 + (optPtr->litFreq[u] >> ZSTD_FREQ_DIV);
             optPtr->litSum += optPtr->litFreq[u];
         }
+
         for (u=0; u<=MaxLL; u++)
             optPtr->litLengthFreq[u] = 1;
+        optPtr->litLengthSum = MaxLL+1;
         for (u=0; u<=MaxML; u++)
             optPtr->matchLengthFreq[u] = 1;
+        optPtr->matchLengthSum = MaxML+1;
         for (u=0; u<=MaxOff; u++)
             optPtr->offCodeFreq[u] = 1;
+        optPtr->offCodeSum = (MaxOff+1);
+
     } else {
-        optPtr->matchLengthSum = 0;
-        optPtr->litLengthSum = 0;
-        optPtr->offCodeSum = 0;
-        optPtr->matchSum = 0;
-        optPtr->litSum = 0;
+        unsigned u;
 
+        optPtr->litSum = 0;
         for (u=0; u<=MaxLit; u++) {
-            optPtr->litFreq[u] = 1 + (optPtr->litFreq[u]>>(ZSTD_FREQ_DIV+1));
+            optPtr->litFreq[u] = 1 + (optPtr->litFreq[u] >> (ZSTD_FREQ_DIV+1));
             optPtr->litSum += optPtr->litFreq[u];
         }
+        optPtr->litLengthSum = 0;
         for (u=0; u<=MaxLL; u++) {
             optPtr->litLengthFreq[u] = 1 + (optPtr->litLengthFreq[u]>>(ZSTD_FREQ_DIV+1));
             optPtr->litLengthSum += optPtr->litLengthFreq[u];
         }
+        optPtr->matchLengthSum = 0;
         for (u=0; u<=MaxML; u++) {
             optPtr->matchLengthFreq[u] = 1 + (optPtr->matchLengthFreq[u]>>ZSTD_FREQ_DIV);
             optPtr->matchLengthSum += optPtr->matchLengthFreq[u];
-            optPtr->matchSum += optPtr->matchLengthFreq[u] * (u + 3);
         }
-        optPtr->matchSum *= ZSTD_LITFREQ_ADD;
+        optPtr->offCodeSum = 0;
         for (u=0; u<=MaxOff; u++) {
             optPtr->offCodeFreq[u] = 1 + (optPtr->offCodeFreq[u]>>ZSTD_FREQ_DIV);
             optPtr->offCodeSum += optPtr->offCodeFreq[u];
         }
     }
 
     ZSTD_setLog2Prices(optPtr);
 }
 
 
-static U32 ZSTD_getLiteralPrice(optState_t* optPtr, U32 litLength, const BYTE* literals)
+/* ZSTD_rawLiteralsCost() :
+ * cost of literals (only) in given segment (which length can be null)
+ * does not include cost of literalLength symbol */
+static U32 ZSTD_rawLiteralsCost(const BYTE* const literals, U32 const litLength,
+                                const optState_t* const optPtr)
 {
-    U32 price, u;
+    if (optPtr->staticPrices) return (litLength*6);  /* 6 bit per literal - no statistic used */
+    if (litLength == 0) return 0;
 
-    if (optPtr->staticPrices)
-        return ZSTD_highbit32((U32)litLength+1) + (litLength*6);
-
-    if (litLength == 0)
-        return optPtr->log2litLengthSum - ZSTD_highbit32(optPtr->litLengthFreq[0]+1);
-
     /* literals */
-    if (optPtr->cachedLiterals == literals) {
-        U32 const additional = litLength - optPtr->cachedLitLength;
-        const BYTE* literals2 = optPtr->cachedLiterals + optPtr->cachedLitLength;
-        price = optPtr->cachedPrice + additional * optPtr->log2litSum;
-        for (u=0; u < additional; u++)
-            price -= ZSTD_highbit32(optPtr->litFreq[literals2[u]]+1);
-        optPtr->cachedPrice = price;
-        optPtr->cachedLitLength = litLength;
-    } else {
-        price = litLength * optPtr->log2litSum;
+    {   U32 u;
+        U32 cost = litLength * optPtr->log2litSum;
         for (u=0; u < litLength; u++)
-            price -= ZSTD_highbit32(optPtr->litFreq[literals[u]]+1);
-
-        if (litLength >= 12) {
-            optPtr->cachedLiterals = literals;
-            optPtr->cachedPrice = price;
-            optPtr->cachedLitLength = litLength;
-        }
+            cost -= ZSTD_highbit32(optPtr->litFreq[literals[u]]+1);
+        return cost;
     }
+}
 
+/* ZSTD_litLengthPrice() :
+ * cost of literalLength symbol */
+static U32 ZSTD_litLengthPrice(U32 const litLength, const optState_t* const optPtr)
+{
+    if (optPtr->staticPrices) return ZSTD_highbit32((U32)litLength+1);
+
     /* literal Length */
-    {   const BYTE LL_deltaCode = 19;
-        const BYTE llCode = (litLength>63) ? (BYTE)ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];
-        price += LL_bits[llCode] + optPtr->log2litLengthSum - ZSTD_highbit32(optPtr->litLengthFreq[llCode]+1);
+    {   U32 const llCode = ZSTD_LLcode(litLength);
+        U32 const price = LL_bits[llCode] + optPtr->log2litLengthSum - ZSTD_highbit32(optPtr->litLengthFreq[llCode]+1);
+        return price;
     }
+}
 
-    return price;
+/* ZSTD_litLengthPrice() :
+ * cost of the literal part of a sequence,
+ * including literals themselves, and literalLength symbol */
+static U32 ZSTD_fullLiteralsCost(const BYTE* const literals, U32 const litLength,
+                                 const optState_t* const optPtr)
+{
+    return ZSTD_rawLiteralsCost(literals, litLength, optPtr)
+         + ZSTD_litLengthPrice(litLength, optPtr);
 }
 
+/* ZSTD_litLengthContribution() :
+ * @return ( cost(litlength) - cost(0) )
+ * this value can then be added to rawLiteralsCost()
+ * to provide a cost which is directly comparable to a match ending at same position */
+static int ZSTD_litLengthContribution(U32 const litLength, const optState_t* const optPtr)
+{
+    if (optPtr->staticPrices) return ZSTD_highbit32(litLength+1);
 
-FORCE_INLINE_TEMPLATE U32 ZSTD_getPrice(optState_t* optPtr, U32 litLength, const BYTE* literals, U32 offset, U32 matchLength, const int ultra)
+    /* literal Length */
+    {   U32 const llCode = ZSTD_LLcode(litLength);
+        int const contribution = LL_bits[llCode]
+                        + ZSTD_highbit32(optPtr->litLengthFreq[0]+1)
+                        - ZSTD_highbit32(optPtr->litLengthFreq[llCode]+1);
+#if 1
+        return contribution;
+#else
+        return MAX(0, contribution); /* sometimes better, sometimes not ... */
+#endif
+    }
+}
+
+/* ZSTD_literalsContribution() :
+ * creates a fake cost for the literals part of a sequence
+ * which can be compared to the ending cost of a match
+ * should a new match start at this position */
+static int ZSTD_literalsContribution(const BYTE* const literals, U32 const litLength,
+                                     const optState_t* const optPtr)
 {
-    /* offset */
+    int const contribution = ZSTD_rawLiteralsCost(literals, litLength, optPtr)
+                           + ZSTD_litLengthContribution(litLength, optPtr);
+    return contribution;
+}
+
+/* ZSTD_getMatchPrice() :
+ * Provides the cost of the match part (offset + matchLength) of a sequence
+ * Must be combined with ZSTD_fullLiteralsCost() to get the full cost of a sequence.
+ * optLevel: when <2, favors small offset for decompression speed (improved cache efficiency) */
+FORCE_INLINE_TEMPLATE U32 ZSTD_getMatchPrice(
+                                    U32 const offset, U32 const matchLength,
+                                    const optState_t* const optPtr,
+                                    int const optLevel)
+{
     U32 price;
-    BYTE const offCode = (BYTE)ZSTD_highbit32(offset+1);
+    U32 const offCode = ZSTD_highbit32(offset+1);
+    U32 const mlBase = matchLength - MINMATCH;
+    assert(matchLength >= MINMATCH);
 
-    if (optPtr->staticPrices)
-        return ZSTD_getLiteralPrice(optPtr, litLength, literals) + ZSTD_highbit32((U32)matchLength+1) + 16 + offCode;
+    if (optPtr->staticPrices)  /* fixed scheme, do not use statistics */
+        return ZSTD_highbit32((U32)mlBase+1) + 16 + offCode;
 
     price = offCode + optPtr->log2offCodeSum - ZSTD_highbit32(optPtr->offCodeFreq[offCode]+1);
-    if (!ultra && offCode >= 20) price += (offCode-19)*2;
+    if ((optLevel<2) /*static*/ && offCode >= 20) price += (offCode-19)*2; /* handicap for long distance offsets, favor decompression speed */
 
     /* match Length */
-    {   const BYTE ML_deltaCode = 36;
-        const BYTE mlCode = (matchLength>127) ? (BYTE)ZSTD_highbit32(matchLength) + ML_deltaCode : ML_Code[matchLength];
+    {   U32 const mlCode = ZSTD_MLcode(mlBase);
         price += ML_bits[mlCode] + optPtr->log2matchLengthSum - ZSTD_highbit32(optPtr->matchLengthFreq[mlCode]+1);
     }
 
-    return price + ZSTD_getLiteralPrice(optPtr, litLength, literals) + optPtr->factor;
+    DEBUGLOG(8, "ZSTD_getMatchPrice(ml:%u) = %u", matchLength, price);
+    return price;
 }
 
-
-static void ZSTD_updatePrice(optState_t* optPtr, U32 litLength, const BYTE* literals, U32 offset, U32 matchLength)
+static void ZSTD_updateStats(optState_t* const optPtr,
+                             U32 litLength, const BYTE* literals,
+                             U32 offsetCode, U32 matchLength)
 {
-    U32 u;
-
     /* literals */
-    optPtr->litSum += litLength*ZSTD_LITFREQ_ADD;
-    for (u=0; u < litLength; u++)
-        optPtr->litFreq[literals[u]] += ZSTD_LITFREQ_ADD;
+    {   U32 u;
+        for (u=0; u < litLength; u++)
+            optPtr->litFreq[literals[u]] += ZSTD_LITFREQ_ADD;
+        optPtr->litSum += litLength*ZSTD_LITFREQ_ADD;
+    }
 
     /* literal Length */
-    {   const BYTE LL_deltaCode = 19;
-        const BYTE llCode = (litLength>63) ? (BYTE)ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];
+    {   U32 const llCode = ZSTD_LLcode(litLength);
         optPtr->litLengthFreq[llCode]++;
         optPtr->litLengthSum++;
     }
 
-    /* match offset */
-    {   BYTE const offCode = (BYTE)ZSTD_highbit32(offset+1);
-        optPtr->offCodeSum++;
+    /* match offset code (0-2=>repCode; 3+=>offset+2) */
+    {   U32 const offCode = ZSTD_highbit32(offsetCode+1);
+        assert(offCode <= MaxOff);
         optPtr->offCodeFreq[offCode]++;
+        optPtr->offCodeSum++;
     }
 
     /* match Length */
-    {   const BYTE ML_deltaCode = 36;
-        const BYTE mlCode = (matchLength>127) ? (BYTE)ZSTD_highbit32(matchLength) + ML_deltaCode : ML_Code[matchLength];
+    {   U32 const mlBase = matchLength - MINMATCH;
+        U32 const mlCode = ZSTD_MLcode(mlBase);
         optPtr->matchLengthFreq[mlCode]++;
         optPtr->matchLengthSum++;
     }
-
-    ZSTD_setLog2Prices(optPtr);
 }
 
 
-#define SET_PRICE(pos, mlen_, offset_, litlen_, price_)   \
-    {                                                 \
-        while (last_pos < pos)  { opt[last_pos+1].price = ZSTD_MAX_PRICE; last_pos++; } \
-        opt[pos].mlen = mlen_;                         \
-        opt[pos].off = offset_;                        \
-        opt[pos].litlen = litlen_;                     \
-        opt[pos].price = price_;                       \
-    }
-
-
-/* function safe only for comparisons */
-static U32 ZSTD_readMINMATCH(const void* memPtr, U32 length)
+/* ZSTD_readMINMATCH() :
+ * function safe only for comparisons
+ * assumption : memPtr must be at least 4 bytes before end of buffer */
+MEM_STATIC U32 ZSTD_readMINMATCH(const void* memPtr, U32 length)
 {
     switch (length)
     {
     default :
     case 4 : return MEM_read32(memPtr);
     case 3 : if (MEM_isLittleEndian())
                 return MEM_read32(memPtr)<<8;
              else
                 return MEM_read32(memPtr)>>8;
     }
 }
 
 
 /* Update hashTable3 up to ip (excluded)
    Assumption : always within prefix (i.e. not within extDict) */
-static
-U32 ZSTD_insertAndFindFirstIndexHash3 (ZSTD_CCtx* zc, const BYTE* ip)
+static U32 ZSTD_insertAndFindFirstIndexHash3 (ZSTD_CCtx* const cctx, const BYTE* const ip)
 {
-    U32* const hashTable3  = zc->hashTable3;
-    U32 const hashLog3  = zc->hashLog3;
-    const BYTE* const base = zc->base;
-    U32 idx = zc->nextToUpdate3;
-    const U32 target = zc->nextToUpdate3 = (U32)(ip - base);
-    const size_t hash3 = ZSTD_hash3Ptr(ip, hashLog3);
+    U32* const hashTable3  = cctx->hashTable3;
+    U32 const hashLog3  = cctx->hashLog3;
+    const BYTE* const base = cctx->base;
+    U32 idx = cctx->nextToUpdate3;
+    U32 const target = cctx->nextToUpdate3 = (U32)(ip - base);
+    size_t const hash3 = ZSTD_hash3Ptr(ip, hashLog3);
 
     while(idx < target) {
         hashTable3[ZSTD_hash3Ptr(base+idx, hashLog3)] = idx;
         idx++;
     }
 
     return hashTable3[hash3];
 }
 
 
 /*-*************************************
 *  Binary Tree search
 ***************************************/
-static U32 ZSTD_insertBtAndGetAllMatches (
-                        ZSTD_CCtx* zc,
-                        const BYTE* const ip, const BYTE* const iLimit,
-                        U32 nbCompares, const U32 mls,
-                        U32 extDict, ZSTD_match_t* matches, const U32 minMatchLen)
+FORCE_INLINE_TEMPLATE
+U32 ZSTD_insertBtAndGetAllMatches (
+                    ZSTD_CCtx* zc,
+                    const BYTE* const ip, const BYTE* const iLimit, int const extDict,
+                    U32 nbCompares, U32 const mls, U32 const sufficient_len,
+                    U32 rep[ZSTD_REP_NUM], U32 const ll0,
+                    ZSTD_match_t* matches, const U32 lengthToBeat)
 {
     const BYTE* const base = zc->base;
-    const U32 current = (U32)(ip-base);
-    const U32 hashLog = zc->appliedParams.cParams.hashLog;
-    const size_t h  = ZSTD_hashPtr(ip, hashLog, mls);
+    U32 const current = (U32)(ip-base);
+    U32 const hashLog = zc->appliedParams.cParams.hashLog;
+    U32 const minMatch = (mls==3) ? 3 : 4;
     U32* const hashTable = zc->hashTable;
+    size_t const h  = ZSTD_hashPtr(ip, hashLog, mls);
     U32 matchIndex  = hashTable[h];
     U32* const bt   = zc->chainTable;
-    const U32 btLog = zc->appliedParams.cParams.chainLog - 1;
-    const U32 btMask= (1U << btLog) - 1;
+    U32 const btLog = zc->appliedParams.cParams.chainLog - 1;
+    U32 const btMask= (1U << btLog) - 1;
     size_t commonLengthSmaller=0, commonLengthLarger=0;
     const BYTE* const dictBase = zc->dictBase;
-    const U32 dictLimit = zc->dictLimit;
+    U32 const dictLimit = zc->dictLimit;
     const BYTE* const dictEnd = dictBase + dictLimit;
     const BYTE* const prefixStart = base + dictLimit;
-    const U32 btLow = btMask >= current ? 0 : current - btMask;
-    const U32 windowLow = zc->lowLimit;
+    U32 const btLow = btMask >= current ? 0 : current - btMask;
+    U32 const windowLow = zc->lowLimit;
     U32* smallerPtr = bt + 2*(current&btMask);
     U32* largerPtr  = bt + 2*(current&btMask) + 1;
-    U32 matchEndIdx = current+8;
+    U32 matchEndIdx = current+8+1;   /* farthest referenced position of any match => detects repetitive patterns */
     U32 dummy32;   /* to be nullified at the end */
     U32 mnum = 0;
 
-    const U32 minMatch = (mls == 3) ? 3 : 4;
-    size_t bestLength = minMatchLen-1;
+    size_t bestLength = lengthToBeat-1;
+    DEBUGLOG(7, "ZSTD_insertBtAndGetAllMatches");
 
-    if (minMatch == 3) { /* HC3 match finder */
+    /* check repCode */
+    {   U32 const lastR = ZSTD_REP_NUM + ll0;
+        U32 repCode;
+        for (repCode = ll0; repCode < lastR; repCode++) {
+            U32 const repOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
+            U32 const repIndex = current - repOffset;
+            U32 repLen = 0;
+            assert(current >= dictLimit);
+            if (repOffset-1 /* intentional overflow, discards 0 and -1 */ < current-dictLimit) {  /* equivalent to `current > repIndex >= dictLimit` */
+                if (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(ip - repOffset, minMatch)) {
+                    repLen = (U32)ZSTD_count(ip+minMatch, ip+minMatch-repOffset, iLimit) + minMatch;
+                }
+            } else {  /* repIndex < dictLimit || repIndex >= current */
+                const BYTE* const repMatch = dictBase + repIndex;
+                assert(current >= windowLow);
+                if ( extDict /* this case only valid in extDict mode */
+                  && ( ((repOffset-1) /*intentional overflow*/ < current - windowLow)  /* equivalent to `current > repIndex >= windowLow` */
+                     & (((U32)((dictLimit-1) - repIndex) >= 3) ) /* intentional overflow : do not test positions overlapping 2 memory segments */)
+                  && (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch)) ) {
+                    repLen = (U32)ZSTD_count_2segments(ip+minMatch, repMatch+minMatch, iLimit, dictEnd, prefixStart) + minMatch;
+            }   }
+            /* save longer solution */
+            if (repLen > bestLength) {
+                DEBUGLOG(8, "found rep-match %u of length %u",
+                            repCode - ll0, (U32)repLen);
+                bestLength = repLen;
+                matches[mnum].off = repCode - ll0;
+                matches[mnum].len = (U32)repLen;
+                mnum++;
+                if ( (repLen > sufficient_len)
+                   | (ip+repLen == iLimit) ) {  /* best possible */
+                    return mnum;
+    }   }   }   }
+
+    /* HC3 match finder */
+    if ((mls == 3) /*static*/ && (bestLength < mls)) {
         U32 const matchIndex3 = ZSTD_insertAndFindFirstIndexHash3 (zc, ip);
-        if (matchIndex3>windowLow && (current - matchIndex3 < (1<<18))) {
-            const BYTE* match;
-            size_t currentMl=0;
-            if ((!extDict) || matchIndex3 >= dictLimit) {
-                match = base + matchIndex3;
-                if (match[bestLength] == ip[bestLength]) currentMl = ZSTD_count(ip, match, iLimit);
+        if ((matchIndex3 > windowLow)
+          & (current - matchIndex3 < (1<<18)) /*heuristic : longer distance likely too expensive*/ ) {
+            size_t mlen;
+            if ((!extDict) /*static*/ || (matchIndex3 >= dictLimit)) {
+                const BYTE* const match = base + matchIndex3;
+                mlen = ZSTD_count(ip, match, iLimit);
             } else {
-                match = dictBase + matchIndex3;
-                if (ZSTD_readMINMATCH(match, MINMATCH) == ZSTD_readMINMATCH(ip, MINMATCH))    /* assumption : matchIndex3 <= dictLimit-4 (by table construction) */
-                    currentMl = ZSTD_count_2segments(ip+MINMATCH, match+MINMATCH, iLimit, dictEnd, prefixStart) + MINMATCH;
+                const BYTE* const match = dictBase + matchIndex3;
+                mlen = ZSTD_count_2segments(ip, match, iLimit, dictEnd, prefixStart);
             }
 
             /* save best solution */
-            if (currentMl > bestLength) {
-                bestLength = currentMl;
-                matches[mnum].off = ZSTD_REP_MOVE_OPT + current - matchIndex3;
-                matches[mnum].len = (U32)currentMl;
-                mnum++;
-                if (currentMl > ZSTD_OPT_NUM) goto update;
-                if (ip+currentMl == iLimit) goto update; /* best possible, and avoid read overflow*/
-            }
-        }
-    }
+            if (mlen >= mls /* == 3 > bestLength */) {
+                DEBUGLOG(8, "found small match with hlog3, of length %u",
+                            (U32)mlen);
+                bestLength = mlen;
+                assert(current > matchIndex3);
+                assert(mnum==0);  /* no prior solution */
+                matches[0].off = (current - matchIndex3) + ZSTD_REP_MOVE;
+                matches[0].len = (U32)mlen;
+                mnum = 1;
+                if ( (mlen > sufficient_len) |
+                     (ip+mlen == iLimit) ) {  /* best possible length */
+                    zc->nextToUpdate = current+1;  /* skip insertion */
+                    return 1;
+    }   }   }   }
 
     hashTable[h] = current;   /* Update Hash Table */
 
     while (nbCompares-- && (matchIndex > windowLow)) {
-        U32* nextPtr = bt + 2*(matchIndex & btMask);
+        U32* const nextPtr = bt + 2*(matchIndex & btMask);
         size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
         const BYTE* match;
+        assert(current > matchIndex);
 
         if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
+            assert(matchIndex+matchLength >= dictLimit);  /* ensure the condition is correct when !extDict */
             match = base + matchIndex;
-            if (match[matchLength] == ip[matchLength]) {
-                matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iLimit) +1;
-            }
+            matchLength += ZSTD_count(ip+matchLength, match+matchLength, iLimit);
         } else {
             match = dictBase + matchIndex;
             matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iLimit, dictEnd, prefixStart);
             if (matchIndex+matchLength >= dictLimit)
-                match = base + matchIndex;   /* to prepare for next usage of match[matchLength] */
+                match = base + matchIndex;   /* prepare for match[matchLength] */
         }
 
         if (matchLength > bestLength) {
-            if (matchLength > matchEndIdx - matchIndex) matchEndIdx = matchIndex + (U32)matchLength;
+            DEBUGLOG(8, "found match of length %u at distance %u",
+                    (U32)matchLength, current - matchIndex);
+            assert(matchEndIdx > matchIndex);
+            if (matchLength > matchEndIdx - matchIndex)
+                matchEndIdx = matchIndex + (U32)matchLength;
             bestLength = matchLength;
-            matches[mnum].off = ZSTD_REP_MOVE_OPT + current - matchIndex;
+            matches[mnum].off = (current - matchIndex) + ZSTD_REP_MOVE;
             matches[mnum].len = (U32)matchLength;
             mnum++;
             if (matchLength > ZSTD_OPT_NUM) break;
-            if (ip+matchLength == iLimit)   /* equal : no way to know if inf or sup */
-                break;   /* drop, to guarantee consistency (miss a little bit of compression) */
+            if (ip+matchLength == iLimit) {  /* equal : no way to know if inf or sup */
+                break;   /* drop, to preserve bt consistency (miss a little bit of compression) */
+            }
         }
 
         if (match[matchLength] < ip[matchLength]) {
-            /* match is smaller than current */
+            /* match smaller than current */
             *smallerPtr = matchIndex;             /* update smaller idx */
             commonLengthSmaller = matchLength;    /* all smaller will now have at least this guaranteed common length */
             if (matchIndex <= btLow) { smallerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
-            smallerPtr = nextPtr+1;               /* new "smaller" => larger of match */
-            matchIndex = nextPtr[1];              /* new matchIndex larger than previous (closer to current) */
+            smallerPtr = nextPtr+1;               /* new candidate => larger than match, which was smaller than current */
+            matchIndex = nextPtr[1];              /* new matchIndex, larger than previous, closer to current */
         } else {
-            /* match is larger than current */
             *largerPtr = matchIndex;
             commonLengthLarger = matchLength;
             if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
             largerPtr = nextPtr;
             matchIndex = nextPtr[0];
     }   }
 
     *smallerPtr = *largerPtr = 0;
 
-update:
-    zc->nextToUpdate = (matchEndIdx > current + 8) ? matchEndIdx - 8 : current+1;
+    assert(matchEndIdx > current+8);
+    zc->nextToUpdate = matchEndIdx - 8;  /* skip repetitive patterns */
     return mnum;
 }
 
 
-/** Tree updater, providing best match */
-static U32 ZSTD_BtGetAllMatches (
-                        ZSTD_CCtx* zc,
-                        const BYTE* const ip, const BYTE* const iLimit,
-                        const U32 maxNbAttempts, const U32 mls, ZSTD_match_t* matches, const U32 minMatchLen)
-{
-    if (ip < zc->base + zc->nextToUpdate) return 0;   /* skipped area */
-    ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
-    return ZSTD_insertBtAndGetAllMatches(zc, ip, iLimit, maxNbAttempts, mls, 0, matches, minMatchLen);
-}
-
-
-static U32 ZSTD_BtGetAllMatches_selectMLS (
+FORCE_INLINE_TEMPLATE U32 ZSTD_BtGetAllMatches (
                         ZSTD_CCtx* zc,   /* Index table will be updated */
-                        const BYTE* ip, const BYTE* const iHighLimit,
-                        const U32 maxNbAttempts, const U32 matchLengthSearch, ZSTD_match_t* matches, const U32 minMatchLen)
+                        const BYTE* ip, const BYTE* const iHighLimit, int const extDict,
+                        U32 const maxNbAttempts, U32 const matchLengthSearch, U32 const sufficient_len,
+                        U32 rep[ZSTD_REP_NUM], U32 const ll0,
+                        ZSTD_match_t* matches, U32 const lengthToBeat)
 {
-    switch(matchLengthSearch)
-    {
-    case 3 : return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 3, matches, minMatchLen);
-    default :
-    case 4 : return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 4, matches, minMatchLen);
-    case 5 : return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 5, matches, minMatchLen);
-    case 7 :
-    case 6 : return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 6, matches, minMatchLen);
-    }
-}
-
-/** Tree updater, providing best match */
-static U32 ZSTD_BtGetAllMatches_extDict (
-                        ZSTD_CCtx* zc,
-                        const BYTE* const ip, const BYTE* const iLimit,
-                        const U32 maxNbAttempts, const U32 mls, ZSTD_match_t* matches, const U32 minMatchLen)
-{
+    DEBUGLOG(7, "ZSTD_BtGetAllMatches");
     if (ip < zc->base + zc->nextToUpdate) return 0;   /* skipped area */
-    ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
-    return ZSTD_insertBtAndGetAllMatches(zc, ip, iLimit, maxNbAttempts, mls, 1, matches, minMatchLen);
-}
-
-
-static U32 ZSTD_BtGetAllMatches_selectMLS_extDict (
-                        ZSTD_CCtx* zc,   /* Index table will be updated */
-                        const BYTE* ip, const BYTE* const iHighLimit,
-                        const U32 maxNbAttempts, const U32 matchLengthSearch, ZSTD_match_t* matches, const U32 minMatchLen)
-{
+    if (extDict) ZSTD_updateTree_extDict(zc, ip, iHighLimit, maxNbAttempts, matchLengthSearch);
+    else ZSTD_updateTree(zc, ip, iHighLimit, maxNbAttempts, matchLengthSearch);
     switch(matchLengthSearch)
     {
-    case 3 : return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 3, matches, minMatchLen);
+    case 3 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 3, sufficient_len, rep, ll0, matches, lengthToBeat);
     default :
-    case 4 : return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 4, matches, minMatchLen);
-    case 5 : return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 5, matches, minMatchLen);
+    case 4 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 4, sufficient_len, rep, ll0, matches, lengthToBeat);
+    case 5 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 5, sufficient_len, rep, ll0, matches, lengthToBeat);
     case 7 :
-    case 6 : return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 6, matches, minMatchLen);
+    case 6 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 6, sufficient_len, rep, ll0, matches, lengthToBeat);
     }
 }
 
 
 /*-*******************************
 *  Optimal parser
 *********************************/
-FORCE_INLINE_TEMPLATE
-size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
-                                      const void* src, size_t srcSize, const int ultra)
-{
-    seqStore_t* seqStorePtr = &(ctx->seqStore);
-    optState_t* optStatePtr = &(ctx->optState);
-    const BYTE* const istart = (const BYTE*)src;
-    const BYTE* ip = istart;
-    const BYTE* anchor = istart;
-    const BYTE* const iend = istart + srcSize;
-    const BYTE* const ilimit = iend - 8;
-    const BYTE* const base = ctx->base;
-    const BYTE* const prefixStart = base + ctx->dictLimit;
+typedef struct repcodes_s {
+    U32 rep[3];
+} repcodes_t;
 
-    const U32 maxSearches = 1U << ctx->appliedParams.cParams.searchLog;
-    const U32 sufficient_len = ctx->appliedParams.cParams.targetLength;
-    const U32 mls = ctx->appliedParams.cParams.searchLength;
-    const U32 minMatch = (ctx->appliedParams.cParams.searchLength == 3) ? 3 : 4;
-
-    ZSTD_optimal_t* opt = optStatePtr->priceTable;
-    ZSTD_match_t* matches = optStatePtr->matchTable;
-    const BYTE* inr;
-    U32 offset, rep[ZSTD_REP_NUM];
-
-    /* init */
-    ctx->nextToUpdate3 = ctx->nextToUpdate;
-    ZSTD_rescaleFreqs(optStatePtr, (const BYTE*)src, srcSize);
-    ip += (ip==prefixStart);
-    { U32 i; for (i=0; irep[i]; }
-
-    /* Match Loop */
-    while (ip < ilimit) {
-        U32 cur, match_num, last_pos, litlen, price;
-        U32 u, mlen, best_mlen, best_off, litLength;
-        memset(opt, 0, sizeof(ZSTD_optimal_t));
-        last_pos = 0;
-        litlen = (U32)(ip - anchor);
-
-        /* check repCode */
-        {   U32 i, last_i = ZSTD_REP_CHECK + (ip==anchor);
-            for (i=(ip == anchor); i 0) && (repCur < (S32)(ip-prefixStart))
-                    && (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(ip - repCur, minMatch))) {
-                    mlen = (U32)ZSTD_count(ip+minMatch, ip+minMatch-repCur, iend) + minMatch;
-                    if (mlen > sufficient_len || mlen >= ZSTD_OPT_NUM) {
-                        best_mlen = mlen; best_off = i; cur = 0; last_pos = 1;
-                        goto _storeSequence;
-                    }
-                    best_off = i - (ip == anchor);
-                    do {
-                        price = ZSTD_getPrice(optStatePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
-                        if (mlen > last_pos || price < opt[mlen].price)
-                            SET_PRICE(mlen, mlen, i, litlen, price);   /* note : macro modifies last_pos */
-                        mlen--;
-                    } while (mlen >= minMatch);
-        }   }   }
-
-        match_num = ZSTD_BtGetAllMatches_selectMLS(ctx, ip, iend, maxSearches, mls, matches, minMatch);
-
-        if (!last_pos && !match_num) { ip++; continue; }
-
-        if (match_num && (matches[match_num-1].len > sufficient_len || matches[match_num-1].len >= ZSTD_OPT_NUM)) {
-            best_mlen = matches[match_num-1].len;
-            best_off = matches[match_num-1].off;
-            cur = 0;
-            last_pos = 1;
-            goto _storeSequence;
+repcodes_t ZSTD_updateRep(U32 const rep[3], U32 const offset, U32 const ll0)
+{
+    repcodes_t newReps;
+    if (offset >= ZSTD_REP_NUM) {  /* full offset */
+        newReps.rep[2] = rep[1];
+        newReps.rep[1] = rep[0];
+        newReps.rep[0] = offset - ZSTD_REP_MOVE;
+    } else {   /* repcode */
+        U32 const repCode = offset + ll0;
+        if (repCode > 0) {  /* note : if repCode==0, no change */
+            U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
+            newReps.rep[2] = (repCode >= 2) ? rep[1] : rep[2];
+            newReps.rep[1] = rep[0];
+            newReps.rep[0] = currentOffset;
+        } else {   /* repCode == 0 */
+            memcpy(&newReps, rep, sizeof(newReps));
         }
+    }
+    return newReps;
+}
 
-        /* set prices using matches at position = 0 */
-        best_mlen = (last_pos) ? last_pos : minMatch;
-        for (u = 0; u < match_num; u++) {
-            mlen = (u>0) ? matches[u-1].len+1 : best_mlen;
-            best_mlen = matches[u].len;
-            while (mlen <= best_mlen) {
-                price = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[u].off-1, mlen - MINMATCH, ultra);
-                if (mlen > last_pos || price < opt[mlen].price)
-                    SET_PRICE(mlen, mlen, matches[u].off, litlen, price);   /* note : macro modifies last_pos */
-                mlen++;
-        }   }
 
-        if (last_pos < minMatch) { ip++; continue; }
+typedef struct {
+    const BYTE* anchor;
+    U32 litlen;
+    U32 rawLitCost;
+} cachedLiteralPrice_t;
 
-        /* initialize opt[0] */
-        { U32 i ; for (i=0; ianchor) {
+        startCost = cachedLitPrice->rawLitCost;
+        startPosition = anchor + cachedLitPrice->litlen;
+        assert(litlen >= cachedLitPrice->litlen);
+        remainingLength = litlen - cachedLitPrice->litlen;
+    } else {
+        startCost = 0;
+        startPosition = anchor;
+        remainingLength = litlen;
+    }
 
-           if (opt[cur-1].mlen == 1) {
-                litlen = opt[cur-1].litlen + 1;
-                if (cur > litlen) {
-                    price = opt[cur - litlen].price + ZSTD_getLiteralPrice(optStatePtr, litlen, inr-litlen);
-                } else
-                    price = ZSTD_getLiteralPrice(optStatePtr, litlen, anchor);
-           } else {
-                litlen = 1;
-                price = opt[cur - 1].price + ZSTD_getLiteralPrice(optStatePtr, litlen, inr-1);
-           }
-
-           if (cur > last_pos || price <= opt[cur].price)
-                SET_PRICE(cur, 1, 0, litlen, price);
-
-           if (cur == last_pos) break;
-
-           if (inr > ilimit)  /* last match must start at a minimum distance of 8 from oend */
-               continue;
-
-           mlen = opt[cur].mlen;
-           if (opt[cur].off > ZSTD_REP_MOVE_OPT) {
-                opt[cur].rep[2] = opt[cur-mlen].rep[1];
-                opt[cur].rep[1] = opt[cur-mlen].rep[0];
-                opt[cur].rep[0] = opt[cur].off - ZSTD_REP_MOVE_OPT;
-           } else {
-                opt[cur].rep[2] = (opt[cur].off > 1) ? opt[cur-mlen].rep[1] : opt[cur-mlen].rep[2];
-                opt[cur].rep[1] = (opt[cur].off > 0) ? opt[cur-mlen].rep[0] : opt[cur-mlen].rep[1];
-                /* If opt[cur].off == ZSTD_REP_MOVE_OPT, then mlen != 1.
-                 * offset ZSTD_REP_MOVE_OPT is used for the special case
-                 * litLength == 0, where offset 0 means something special.
-                 * mlen == 1 means the previous byte was stored as a literal,
-                 * so they are mutually exclusive.
-                 */
-                assert(!(opt[cur].off == ZSTD_REP_MOVE_OPT && mlen == 1));
-                opt[cur].rep[0] = (opt[cur].off == ZSTD_REP_MOVE_OPT) ? (opt[cur-mlen].rep[0] - 1) : (opt[cur-mlen].rep[opt[cur].off]);
-           }
-
-            best_mlen = minMatch;
-            {   U32 i, last_i = ZSTD_REP_CHECK + (mlen != 1);
-                for (i=(opt[cur].mlen != 1); i 0) && (repCur < (S32)(inr-prefixStart))
-                       && (ZSTD_readMINMATCH(inr, minMatch) == ZSTD_readMINMATCH(inr - repCur, minMatch))) {
-                       mlen = (U32)ZSTD_count(inr+minMatch, inr+minMatch - repCur, iend) + minMatch;
-
-                       if (mlen > sufficient_len || cur + mlen >= ZSTD_OPT_NUM) {
-                            best_mlen = mlen; best_off = i; last_pos = cur + 1;
-                            goto _storeSequence;
-                       }
-
-                       best_off = i - (opt[cur].mlen != 1);
-                       if (mlen > best_mlen) best_mlen = mlen;
-
-                       do {
-                           if (opt[cur].mlen == 1) {
-                                litlen = opt[cur].litlen;
-                                if (cur > litlen) {
-                                    price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, inr-litlen, best_off, mlen - MINMATCH, ultra);
-                                } else
-                                    price = ZSTD_getPrice(optStatePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
-                            } else {
-                                litlen = 0;
-                                price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, best_off, mlen - MINMATCH, ultra);
-                            }
-
-                            if (cur + mlen > last_pos || price <= opt[cur + mlen].price)
-                                SET_PRICE(cur + mlen, mlen, i, litlen, price);
-                            mlen--;
-                        } while (mlen >= minMatch);
-            }   }   }
-
-            match_num = ZSTD_BtGetAllMatches_selectMLS(ctx, inr, iend, maxSearches, mls, matches, best_mlen);
-
-            if (match_num > 0 && (matches[match_num-1].len > sufficient_len || cur + matches[match_num-1].len >= ZSTD_OPT_NUM)) {
-                best_mlen = matches[match_num-1].len;
-                best_off = matches[match_num-1].off;
-                last_pos = cur + 1;
-                goto _storeSequence;
-            }
-
-            /* set prices using matches at position = cur */
-            for (u = 0; u < match_num; u++) {
-                mlen = (u>0) ? matches[u-1].len+1 : best_mlen;
-                best_mlen = matches[u].len;
-
-                while (mlen <= best_mlen) {
-                    if (opt[cur].mlen == 1) {
-                        litlen = opt[cur].litlen;
-                        if (cur > litlen)
-                            price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, ip+cur-litlen, matches[u].off-1, mlen - MINMATCH, ultra);
-                        else
-                            price = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[u].off-1, mlen - MINMATCH, ultra);
-                    } else {
-                        litlen = 0;
-                        price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, matches[u].off-1, mlen - MINMATCH, ultra);
-                    }
-
-                    if (cur + mlen > last_pos || (price < opt[cur + mlen].price))
-                        SET_PRICE(cur + mlen, mlen, matches[u].off, litlen, price);
-
-                    mlen++;
-        }   }   }
-
-        best_mlen = opt[last_pos].mlen;
-        best_off = opt[last_pos].off;
-        cur = last_pos - best_mlen;
-
-        /* store sequence */
-_storeSequence:   /* cur, last_pos, best_mlen, best_off have to be set */
-        opt[0].mlen = 1;
-
-        while (1) {
-            mlen = opt[cur].mlen;
-            offset = opt[cur].off;
-            opt[cur].mlen = best_mlen;
-            opt[cur].off = best_off;
-            best_mlen = mlen;
-            best_off = offset;
-            if (mlen > cur) break;
-            cur -= mlen;
-        }
-
-        for (u = 0; u <= last_pos;) {
-            u += opt[u].mlen;
-        }
-
-        for (cur=0; cur < last_pos; ) {
-            mlen = opt[cur].mlen;
-            if (mlen == 1) { ip++; cur++; continue; }
-            offset = opt[cur].off;
-            cur += mlen;
-            litLength = (U32)(ip - anchor);
-
-            if (offset > ZSTD_REP_MOVE_OPT) {
-                rep[2] = rep[1];
-                rep[1] = rep[0];
-                rep[0] = offset - ZSTD_REP_MOVE_OPT;
-                offset--;
-            } else {
-                if (offset != 0) {
-                    best_off = (offset==ZSTD_REP_MOVE_OPT) ? (rep[0] - 1) : (rep[offset]);
-                    if (offset != 1) rep[2] = rep[1];
-                    rep[1] = rep[0];
-                    rep[0] = best_off;
-                }
-                if (litLength==0) offset--;
-            }
-
-            ZSTD_updatePrice(optStatePtr, litLength, anchor, offset, mlen-MINMATCH);
-            ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, mlen-MINMATCH);
-            anchor = ip = ip + mlen;
-    }    }   /* for (cur=0; cur < last_pos; ) */
-
-    /* Save reps for next block */
-    { int i; for (i=0; irepToConfirm[i] = rep[i]; }
-
-    /* Return the last literals size */
-    return iend - anchor;
+    {   U32 const rawLitCost = startCost + ZSTD_rawLiteralsCost(startPosition, remainingLength, optStatePtr);
+        cachedLitPrice->anchor = anchor;
+        cachedLitPrice->litlen = litlen;
+        cachedLitPrice->rawLitCost = rawLitCost;
+        return rawLitCost;
+    }
 }
 
-
-size_t ZSTD_compressBlock_btopt(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
+static U32 ZSTD_fullLiteralsCost_cached(
+                            cachedLiteralPrice_t* const cachedLitPrice,
+                            const BYTE* const anchor, U32 const litlen,
+                            const optState_t* const optStatePtr)
 {
-    return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 0);
+    return ZSTD_rawLiteralsCost_cached(cachedLitPrice, anchor, litlen, optStatePtr)
+         + ZSTD_litLengthPrice(litlen, optStatePtr);
 }
 
-size_t ZSTD_compressBlock_btultra(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
+static int ZSTD_literalsContribution_cached(
+                            cachedLiteralPrice_t* const cachedLitPrice,
+                            const BYTE* const anchor, U32 const litlen,
+                            const optState_t* const optStatePtr)
 {
-    return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 1);
+    int const contribution = ZSTD_rawLiteralsCost_cached(cachedLitPrice, anchor, litlen, optStatePtr)
+                           + ZSTD_litLengthContribution(litlen, optStatePtr);
+    return contribution;
 }
 
-
 FORCE_INLINE_TEMPLATE
-size_t ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
-                                     const void* src, size_t srcSize, const int ultra)
+size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
+                                      const void* src, size_t srcSize,
+                                      const int optLevel, const int extDict)
 {
-    seqStore_t* seqStorePtr = &(ctx->seqStore);
-    optState_t* optStatePtr = &(ctx->optState);
+    seqStore_t* const seqStorePtr = &(ctx->seqStore);
+    optState_t* const optStatePtr = &(ctx->optState);
     const BYTE* const istart = (const BYTE*)src;
     const BYTE* ip = istart;
     const BYTE* anchor = istart;
     const BYTE* const iend = istart + srcSize;
     const BYTE* const ilimit = iend - 8;
     const BYTE* const base = ctx->base;
-    const U32 lowestIndex = ctx->lowLimit;
-    const U32 dictLimit = ctx->dictLimit;
-    const BYTE* const prefixStart = base + dictLimit;
-    const BYTE* const dictBase = ctx->dictBase;
-    const BYTE* const dictEnd  = dictBase + dictLimit;
+    const BYTE* const prefixStart = base + ctx->dictLimit;
 
-    const U32 maxSearches = 1U << ctx->appliedParams.cParams.searchLog;
-    const U32 sufficient_len = ctx->appliedParams.cParams.targetLength;
-    const U32 mls = ctx->appliedParams.cParams.searchLength;
-    const U32 minMatch = (ctx->appliedParams.cParams.searchLength == 3) ? 3 : 4;
+    U32 const maxSearches = 1U << ctx->appliedParams.cParams.searchLog;
+    U32 const sufficient_len = MIN(ctx->appliedParams.cParams.targetLength, ZSTD_OPT_NUM -1);
+    U32 const mls = ctx->appliedParams.cParams.searchLength;
+    U32 const minMatch = (ctx->appliedParams.cParams.searchLength == 3) ? 3 : 4;
 
-    ZSTD_optimal_t* opt = optStatePtr->priceTable;
-    ZSTD_match_t* matches = optStatePtr->matchTable;
-    const BYTE* inr;
+    ZSTD_optimal_t* const opt = optStatePtr->priceTable;
+    ZSTD_match_t* const matches = optStatePtr->matchTable;
+    cachedLiteralPrice_t cachedLitPrice;
+    U32 rep[ZSTD_REP_NUM];
 
     /* init */
-    U32 offset, rep[ZSTD_REP_NUM];
-    { U32 i; for (i=0; irep[i]; }
-
+    DEBUGLOG(5, "ZSTD_compressBlock_opt_generic");
     ctx->nextToUpdate3 = ctx->nextToUpdate;
     ZSTD_rescaleFreqs(optStatePtr, (const BYTE*)src, srcSize);
     ip += (ip==prefixStart);
+    { int i; for (i=0; irep[i]; }
+    memset(&cachedLitPrice, 0, sizeof(cachedLitPrice));
 
     /* Match Loop */
     while (ip < ilimit) {
-        U32 cur, match_num, last_pos, litlen, price;
-        U32 u, mlen, best_mlen, best_off, litLength;
-        U32 current = (U32)(ip-base);
-        memset(opt, 0, sizeof(ZSTD_optimal_t));
-        last_pos = 0;
-        opt[0].litlen = (U32)(ip - anchor);
+        U32 cur, last_pos = 0;
+        U32 best_mlen, best_off;
 
-        /* check repCode */
-        {   U32 i, last_i = ZSTD_REP_CHECK + (ip==anchor);
-            for (i = (ip==anchor); i 0 && repCur <= (S32)current)
-                   && (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex>lowestIndex))  /* intentional overflow */
-                   && (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch)) ) {
-                    /* repcode detected we should take it */
-                    const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
-                    mlen = (U32)ZSTD_count_2segments(ip+minMatch, repMatch+minMatch, iend, repEnd, prefixStart) + minMatch;
+        /* find first match */
+        {   U32 const litlen = (U32)(ip - anchor);
+            U32 const ll0 = !litlen;
+            U32 const nbMatches = ZSTD_BtGetAllMatches(ctx, ip, iend, extDict, maxSearches, mls, sufficient_len, rep, ll0, matches, minMatch);
+            if (!nbMatches) { ip++; continue; }
 
-                    if (mlen > sufficient_len || mlen >= ZSTD_OPT_NUM) {
-                        best_mlen = mlen; best_off = i; cur = 0; last_pos = 1;
-                        goto _storeSequence;
-                    }
+            /* initialize opt[0] */
+            { U32 i ; for (i=0; i last_pos || price < opt[mlen].price)
-                            SET_PRICE(mlen, mlen, i, litlen, price);   /* note : macro modifies last_pos */
-                        mlen--;
-                    } while (mlen >= minMatch);
-        }   }   }
+            /* large match -> immediate encoding */
+            {   U32 const maxML = matches[nbMatches-1].len;
+                DEBUGLOG(7, "found %u matches of maxLength=%u and offset=%u at cPos=%u => start new serie",
+                            nbMatches, maxML, matches[nbMatches-1].off, (U32)(ip-prefixStart));
 
-        match_num = ZSTD_BtGetAllMatches_selectMLS_extDict(ctx, ip, iend, maxSearches, mls, matches, minMatch);  /* first search (depth 0) */
+                if (maxML > sufficient_len) {
+                    best_mlen = maxML;
+                    best_off = matches[nbMatches-1].off;
+                    DEBUGLOG(7, "large match (%u>%u), immediate encoding",
+                                best_mlen, sufficient_len);
+                    cur = 0;
+                    last_pos = 1;
+                    goto _shortestPath;
+            }   }
 
-        if (!last_pos && !match_num) { ip++; continue; }
-
-        { U32 i; for (i=0; i sufficient_len || matches[match_num-1].len >= ZSTD_OPT_NUM)) {
-            best_mlen = matches[match_num-1].len;
-            best_off = matches[match_num-1].off;
-            cur = 0;
-            last_pos = 1;
-            goto _storeSequence;
+            /* set prices for first matches starting position == 0 */
+            {   U32 const literalsPrice = ZSTD_fullLiteralsCost_cached(&cachedLitPrice, anchor, litlen, optStatePtr);
+                U32 pos;
+                U32 matchNb;
+                for (pos = 0; pos < minMatch; pos++) {
+                    opt[pos].mlen = 1;
+                    opt[pos].price = ZSTD_MAX_PRICE;
+                }
+                for (matchNb = 0; matchNb < nbMatches; matchNb++) {
+                    U32 const offset = matches[matchNb].off;
+                    U32 const end = matches[matchNb].len;
+                    repcodes_t const repHistory = ZSTD_updateRep(rep, offset, ll0);
+                    for ( ; pos <= end ; pos++ ) {
+                        U32 const matchPrice = literalsPrice + ZSTD_getMatchPrice(offset, pos, optStatePtr, optLevel);
+                        DEBUGLOG(7, "rPos:%u => set initial price : %u",
+                                    pos, matchPrice);
+                        opt[pos].mlen = pos;
+                        opt[pos].off = offset;
+                        opt[pos].litlen = litlen;
+                        opt[pos].price = matchPrice;
+                        memcpy(opt[pos].rep, &repHistory, sizeof(repHistory));
+                }   }
+                last_pos = pos-1;
+            }
         }
 
-        best_mlen = (last_pos) ? last_pos : minMatch;
-
-        /* set prices using matches at position = 0 */
-        for (u = 0; u < match_num; u++) {
-            mlen = (u>0) ? matches[u-1].len+1 : best_mlen;
-            best_mlen = matches[u].len;
-            litlen = opt[0].litlen;
-            while (mlen <= best_mlen) {
-                price = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[u].off-1, mlen - MINMATCH, ultra);
-                if (mlen > last_pos || price < opt[mlen].price)
-                    SET_PRICE(mlen, mlen, matches[u].off, litlen, price);
-                mlen++;
-        }   }
-
-        if (last_pos < minMatch) {
-            ip++; continue;
-        }
-
         /* check further positions */
         for (cur = 1; cur <= last_pos; cur++) {
-            inr = ip + cur;
+            const BYTE* const inr = ip + cur;
+            assert(cur < ZSTD_OPT_NUM);
 
-            if (opt[cur-1].mlen == 1) {
-                litlen = opt[cur-1].litlen + 1;
+            /* Fix current position with one literal if cheaper */
+            {   U32 const litlen = (opt[cur-1].mlen == 1) ? opt[cur-1].litlen + 1 : 1;
+                int price;  /* note : contribution can be negative */
                 if (cur > litlen) {
-                    price = opt[cur - litlen].price + ZSTD_getLiteralPrice(optStatePtr, litlen, inr-litlen);
-                } else
-                    price = ZSTD_getLiteralPrice(optStatePtr, litlen, anchor);
-            } else {
-                litlen = 1;
-                price = opt[cur - 1].price + ZSTD_getLiteralPrice(optStatePtr, litlen, inr-1);
-            }
+                    price = opt[cur - litlen].price + ZSTD_literalsContribution(inr-litlen, litlen, optStatePtr);
+                } else {
+                    price = ZSTD_literalsContribution_cached(&cachedLitPrice, anchor, litlen, optStatePtr);
+                }
+                assert(price < 1000000000); /* overflow check */
+                if (price <= opt[cur].price) {
+                    DEBUGLOG(7, "rPos:%u : better price (%u<%u) using literal",
+                                cur, price, opt[cur].price);
+                    opt[cur].mlen = 1;
+                    opt[cur].off = 0;
+                    opt[cur].litlen = litlen;
+                    opt[cur].price = price;
+                    memcpy(opt[cur].rep, opt[cur-1].rep, sizeof(opt[cur].rep));
+            }   }
 
-            if (cur > last_pos || price <= opt[cur].price)
-                SET_PRICE(cur, 1, 0, litlen, price);
+            /* last match must start at a minimum distance of 8 from oend */
+            if (inr > ilimit) continue;
 
             if (cur == last_pos) break;
 
-            if (inr > ilimit)  /* last match must start at a minimum distance of 8 from oend */
-                continue;
+             if ( (optLevel==0) /*static*/
+               && (opt[cur+1].price <= opt[cur].price) )
+                continue;  /* skip unpromising positions; about ~+6% speed, -0.01 ratio */
 
-            mlen = opt[cur].mlen;
-            if (opt[cur].off > ZSTD_REP_MOVE_OPT) {
-                opt[cur].rep[2] = opt[cur-mlen].rep[1];
-                opt[cur].rep[1] = opt[cur-mlen].rep[0];
-                opt[cur].rep[0] = opt[cur].off - ZSTD_REP_MOVE_OPT;
-            } else {
-                opt[cur].rep[2] = (opt[cur].off > 1) ? opt[cur-mlen].rep[1] : opt[cur-mlen].rep[2];
-                opt[cur].rep[1] = (opt[cur].off > 0) ? opt[cur-mlen].rep[0] : opt[cur-mlen].rep[1];
-                assert(!(opt[cur].off == ZSTD_REP_MOVE_OPT && mlen == 1));
-                opt[cur].rep[0] = (opt[cur].off == ZSTD_REP_MOVE_OPT) ? (opt[cur-mlen].rep[0] - 1) : (opt[cur-mlen].rep[opt[cur].off]);
-            }
+            {   U32 const ll0 = (opt[cur].mlen != 1);
+                U32 const litlen = (opt[cur].mlen == 1) ? opt[cur].litlen : 0;
+                U32 const previousPrice = (cur > litlen) ? opt[cur-litlen].price : 0;
+                U32 const basePrice = previousPrice + ZSTD_fullLiteralsCost(inr-litlen, litlen, optStatePtr);
+                U32 const nbMatches = ZSTD_BtGetAllMatches(ctx, inr, iend, extDict, maxSearches, mls, sufficient_len, opt[cur].rep, ll0, matches, minMatch);
+                U32 matchNb;
+                if (!nbMatches) continue;
 
-            best_mlen = minMatch;
-            {   U32 i, last_i = ZSTD_REP_CHECK + (mlen != 1);
-                for (i = (mlen != 1); i 0 && repCur <= (S32)(current+cur))
-                      && (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex>lowestIndex))  /* intentional overflow */
-                      && (ZSTD_readMINMATCH(inr, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch)) ) {
-                        /* repcode detected */
-                        const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
-                        mlen = (U32)ZSTD_count_2segments(inr+minMatch, repMatch+minMatch, iend, repEnd, prefixStart) + minMatch;
+                {   U32 const maxML = matches[nbMatches-1].len;
+                    DEBUGLOG(7, "rPos:%u, found %u matches, of maxLength=%u",
+                                cur, nbMatches, maxML);
 
-                        if (mlen > sufficient_len || cur + mlen >= ZSTD_OPT_NUM) {
-                            best_mlen = mlen; best_off = i; last_pos = cur + 1;
-                            goto _storeSequence;
-                        }
+                    if ( (maxML > sufficient_len)
+                       | (cur + maxML >= ZSTD_OPT_NUM) ) {
+                        best_mlen = maxML;
+                        best_off = matches[nbMatches-1].off;
+                        last_pos = cur + 1;
+                        goto _shortestPath;
+                    }
+                }
 
-                        best_off = i - (opt[cur].mlen != 1);
-                        if (mlen > best_mlen) best_mlen = mlen;
+                /* set prices using matches found at position == cur */
+                for (matchNb = 0; matchNb < nbMatches; matchNb++) {
+                    U32 const offset = matches[matchNb].off;
+                    repcodes_t const repHistory = ZSTD_updateRep(opt[cur].rep, offset, ll0);
+                    U32 const lastML = matches[matchNb].len;
+                    U32 const startML = (matchNb>0) ? matches[matchNb-1].len+1 : minMatch;
+                    U32 mlen;
 
-                        do {
-                            if (opt[cur].mlen == 1) {
-                                litlen = opt[cur].litlen;
-                                if (cur > litlen) {
-                                    price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, inr-litlen, best_off, mlen - MINMATCH, ultra);
-                                } else
-                                    price = ZSTD_getPrice(optStatePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
-                            } else {
-                                litlen = 0;
-                                price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, best_off, mlen - MINMATCH, ultra);
-                            }
+                    DEBUGLOG(7, "testing match %u => offCode=%u, mlen=%u, llen=%u",
+                                matchNb, matches[matchNb].off, lastML, litlen);
 
-                            if (cur + mlen > last_pos || price <= opt[cur + mlen].price)
-                                SET_PRICE(cur + mlen, mlen, i, litlen, price);
-                            mlen--;
-                        } while (mlen >= minMatch);
+                    for (mlen = lastML; mlen >= startML; mlen--) {
+                        U32 const pos = cur + mlen;
+                        int const price = basePrice + ZSTD_getMatchPrice(offset, mlen, optStatePtr, optLevel);
+
+                        if ((pos > last_pos) || (price < opt[pos].price)) {
+                            DEBUGLOG(7, "rPos:%u => new better price (%u<%u)",
+                                        pos, price, opt[pos].price);
+                            while (last_pos < pos) { opt[last_pos+1].price = ZSTD_MAX_PRICE; last_pos++; }
+                            opt[pos].mlen = mlen;
+                            opt[pos].off = offset;
+                            opt[pos].litlen = litlen;
+                            opt[pos].price = price;
+                            memcpy(opt[pos].rep, &repHistory, sizeof(repHistory));
+                        } else {
+                            if (optLevel==0) break;  /* gets ~+10% speed for about -0.01 ratio loss */
+                        }
             }   }   }
+        }  /* for (cur = 1; cur <= last_pos; cur++) */
 
-            match_num = ZSTD_BtGetAllMatches_selectMLS_extDict(ctx, inr, iend, maxSearches, mls, matches, minMatch);
-
-            if (match_num > 0 && (matches[match_num-1].len > sufficient_len || cur + matches[match_num-1].len >= ZSTD_OPT_NUM)) {
-                best_mlen = matches[match_num-1].len;
-                best_off = matches[match_num-1].off;
-                last_pos = cur + 1;
-                goto _storeSequence;
-            }
-
-            /* set prices using matches at position = cur */
-            for (u = 0; u < match_num; u++) {
-                mlen = (u>0) ? matches[u-1].len+1 : best_mlen;
-                best_mlen = matches[u].len;
-
-                while (mlen <= best_mlen) {
-                    if (opt[cur].mlen == 1) {
-                        litlen = opt[cur].litlen;
-                        if (cur > litlen)
-                            price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, ip+cur-litlen, matches[u].off-1, mlen - MINMATCH, ultra);
-                        else
-                            price = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[u].off-1, mlen - MINMATCH, ultra);
-                    } else {
-                        litlen = 0;
-                        price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, matches[u].off-1, mlen - MINMATCH, ultra);
-                    }
-
-                    if (cur + mlen > last_pos || (price < opt[cur + mlen].price))
-                        SET_PRICE(cur + mlen, mlen, matches[u].off, litlen, price);
-
-                    mlen++;
-        }   }   }   /* for (cur = 1; cur <= last_pos; cur++) */
-
         best_mlen = opt[last_pos].mlen;
         best_off = opt[last_pos].off;
         cur = last_pos - best_mlen;
 
-        /* store sequence */
-_storeSequence:   /* cur, last_pos, best_mlen, best_off have to be set */
-        opt[0].mlen = 1;
+_shortestPath:   /* cur, last_pos, best_mlen, best_off have to be set */
+        assert(opt[0].mlen == 1);
 
-        while (1) {
-            mlen = opt[cur].mlen;
-            offset = opt[cur].off;
-            opt[cur].mlen = best_mlen;
-            opt[cur].off = best_off;
-            best_mlen = mlen;
-            best_off = offset;
-            if (mlen > cur) break;
-            cur -= mlen;
-        }
+        /* reverse traversal */
+        DEBUGLOG(7, "start reverse traversal (last_pos:%u, cur:%u)",
+                    last_pos, cur);
+        {   U32 selectedMatchLength = best_mlen;
+            U32 selectedOffset = best_off;
+            U32 pos = cur;
+            while (1) {
+                U32 const mlen = opt[pos].mlen;
+                U32 const off = opt[pos].off;
+                opt[pos].mlen = selectedMatchLength;
+                opt[pos].off = selectedOffset;
+                selectedMatchLength = mlen;
+                selectedOffset = off;
+                if (mlen > pos) break;
+                pos -= mlen;
+        }   }
 
-        for (u = 0; u <= last_pos; ) {
-            u += opt[u].mlen;
-        }
+        /* save sequences */
+        {   U32 pos;
+            for (pos=0; pos < last_pos; ) {
+                U32 const llen = (U32)(ip - anchor);
+                U32 const mlen = opt[pos].mlen;
+                U32 const offset = opt[pos].off;
+                if (mlen == 1) { ip++; pos++; continue; }  /* literal position => move on */
+                pos += mlen; ip += mlen;
 
-        for (cur=0; cur < last_pos; ) {
-            mlen = opt[cur].mlen;
-            if (mlen == 1) { ip++; cur++; continue; }
-            offset = opt[cur].off;
-            cur += mlen;
-            litLength = (U32)(ip - anchor);
-
-            if (offset > ZSTD_REP_MOVE_OPT) {
-                rep[2] = rep[1];
-                rep[1] = rep[0];
-                rep[0] = offset - ZSTD_REP_MOVE_OPT;
-                offset--;
-            } else {
-                if (offset != 0) {
-                    best_off = (offset==ZSTD_REP_MOVE_OPT) ? (rep[0] - 1) : (rep[offset]);
-                    if (offset != 1) rep[2] = rep[1];
+                /* repcodes update : like ZSTD_updateRep(), but update in place */
+                if (offset >= ZSTD_REP_NUM) {  /* full offset */
+                    rep[2] = rep[1];
                     rep[1] = rep[0];
-                    rep[0] = best_off;
+                    rep[0] = offset - ZSTD_REP_MOVE;
+                } else {   /* repcode */
+                    U32 const repCode = offset + (llen==0);
+                    if (repCode) {  /* note : if repCode==0, no change */
+                        U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
+                        if (repCode >= 2) rep[2] = rep[1];
+                        rep[1] = rep[0];
+                        rep[0] = currentOffset;
+                    }
                 }
 
-                if (litLength==0) offset--;
-            }
+                ZSTD_updateStats(optStatePtr, llen, anchor, offset, mlen);
+                ZSTD_storeSeq(seqStorePtr, llen, anchor, offset, mlen-MINMATCH);
+                anchor = ip;
+        }   }
+        ZSTD_setLog2Prices(optStatePtr);
+    }   /* while (ip < ilimit) */
 
-            ZSTD_updatePrice(optStatePtr, litLength, anchor, offset, mlen-MINMATCH);
-            ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, mlen-MINMATCH);
-            anchor = ip = ip + mlen;
-    }    }   /* for (cur=0; cur < last_pos; ) */
-
     /* Save reps for next block */
     { int i; for (i=0; irepToConfirm[i] = rep[i]; }
 
     /* Return the last literals size */
     return iend - anchor;
 }
 
 
+size_t ZSTD_compressBlock_btopt(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
+{
+    DEBUGLOG(5, "ZSTD_compressBlock_btopt");
+    return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 0 /*optLevel*/, 0 /*extDict*/);
+}
+
+size_t ZSTD_compressBlock_btultra(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
+{
+    return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 2 /*optLevel*/, 0 /*extDict*/);
+}
+
 size_t ZSTD_compressBlock_btopt_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
-    return ZSTD_compressBlock_opt_extDict_generic(ctx, src, srcSize, 0);
+    return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 0 /*optLevel*/, 1 /*extDict*/);
 }
 
 size_t ZSTD_compressBlock_btultra_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
-    return ZSTD_compressBlock_opt_extDict_generic(ctx, src, srcSize, 1);
+    return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 2 /*optLevel*/, 1 /*extDict*/);
 }
Index: head/sys/contrib/zstd/lib/compress/zstd_opt.h
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstd_opt.h	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstd_opt.h	(revision 330894)
@@ -1,30 +1,30 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 #ifndef ZSTD_OPT_H
 #define ZSTD_OPT_H
 
-#include "zstd_compress.h"
-
 #if defined (__cplusplus)
 extern "C" {
 #endif
+
+#include "zstd.h"   /* ZSTD_CCtx, size_t */
 
 size_t ZSTD_compressBlock_btopt(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_btultra(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 
 size_t ZSTD_compressBlock_btopt_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_btultra_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif /* ZSTD_OPT_H */
Index: head/sys/contrib/zstd/lib/compress/zstdmt_compress.c
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstdmt_compress.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstdmt_compress.c	(revision 330894)
@@ -1,1099 +1,1149 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 
 /* ======   Tuning parameters   ====== */
 #define ZSTDMT_NBTHREADS_MAX 200
 #define ZSTDMT_OVERLAPLOG_DEFAULT 6
 
 
 /* ======   Compiler specifics   ====== */
 #if defined(_MSC_VER)
 #  pragma warning(disable : 4204)   /* disable: C4204: non-constant aggregate initializer */
 #endif
 
 
 /* ======   Dependencies   ====== */
 #include       /* memcpy, memset */
 #include "pool.h"        /* threadpool */
 #include "threading.h"   /* mutex */
-#include "zstd_internal.h"  /* MIN, ERROR, ZSTD_*, ZSTD_highbit32 */
+#include "zstd_compress_internal.h"  /* MIN, ERROR, ZSTD_*, ZSTD_highbit32 */
 #include "zstdmt_compress.h"
 
 
 /* ======   Debug   ====== */
 #if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=2)
 
 #  include 
 #  include 
 #  include 
 #  define DEBUGLOGRAW(l, ...) if (l<=ZSTD_DEBUG) { fprintf(stderr, __VA_ARGS__); }
 
 #  define DEBUG_PRINTHEX(l,p,n) {            \
     unsigned debug_u;                        \
     for (debug_u=0; debug_u<(n); debug_u++)  \
         DEBUGLOGRAW(l, "%02X ", ((const unsigned char*)(p))[debug_u]); \
     DEBUGLOGRAW(l, " \n");                   \
 }
 
 static unsigned long long GetCurrentClockTimeMicroseconds(void)
 {
    static clock_t _ticksPerSecond = 0;
    if (_ticksPerSecond <= 0) _ticksPerSecond = sysconf(_SC_CLK_TCK);
 
    { struct tms junk; clock_t newTicks = (clock_t) times(&junk);
      return ((((unsigned long long)newTicks)*(1000000))/_ticksPerSecond); }
 }
 
 #define MUTEX_WAIT_TIME_DLEVEL 6
 #define ZSTD_PTHREAD_MUTEX_LOCK(mutex) {          \
     if (ZSTD_DEBUG >= MUTEX_WAIT_TIME_DLEVEL) {   \
         unsigned long long const beforeTime = GetCurrentClockTimeMicroseconds(); \
         ZSTD_pthread_mutex_lock(mutex);           \
         {   unsigned long long const afterTime = GetCurrentClockTimeMicroseconds(); \
             unsigned long long const elapsedTime = (afterTime-beforeTime); \
             if (elapsedTime > 1000) {  /* or whatever threshold you like; I'm using 1 millisecond here */ \
                 DEBUGLOG(MUTEX_WAIT_TIME_DLEVEL, "Thread took %llu microseconds to acquire mutex %s \n", \
                    elapsedTime, #mutex);          \
         }   }                                     \
     } else {                                      \
         ZSTD_pthread_mutex_lock(mutex);           \
     }                                             \
 }
 
 #else
 
 #  define ZSTD_PTHREAD_MUTEX_LOCK(m) ZSTD_pthread_mutex_lock(m)
 #  define DEBUG_PRINTHEX(l,p,n) {}
 
 #endif
 
 
 /* =====   Buffer Pool   ===== */
 /* a single Buffer Pool can be invoked from multiple threads in parallel */
 
 typedef struct buffer_s {
     void* start;
     size_t size;
 } buffer_t;
 
 static const buffer_t g_nullBuffer = { NULL, 0 };
 
 typedef struct ZSTDMT_bufferPool_s {
     ZSTD_pthread_mutex_t poolMutex;
     size_t bufferSize;
     unsigned totalBuffers;
     unsigned nbBuffers;
     ZSTD_customMem cMem;
     buffer_t bTable[1];   /* variable size */
 } ZSTDMT_bufferPool;
 
 static ZSTDMT_bufferPool* ZSTDMT_createBufferPool(unsigned nbThreads, ZSTD_customMem cMem)
 {
     unsigned const maxNbBuffers = 2*nbThreads + 3;
     ZSTDMT_bufferPool* const bufPool = (ZSTDMT_bufferPool*)ZSTD_calloc(
         sizeof(ZSTDMT_bufferPool) + (maxNbBuffers-1) * sizeof(buffer_t), cMem);
     if (bufPool==NULL) return NULL;
     if (ZSTD_pthread_mutex_init(&bufPool->poolMutex, NULL)) {
         ZSTD_free(bufPool, cMem);
         return NULL;
     }
     bufPool->bufferSize = 64 KB;
     bufPool->totalBuffers = maxNbBuffers;
     bufPool->nbBuffers = 0;
     bufPool->cMem = cMem;
     return bufPool;
 }
 
 static void ZSTDMT_freeBufferPool(ZSTDMT_bufferPool* bufPool)
 {
     unsigned u;
     DEBUGLOG(3, "ZSTDMT_freeBufferPool (address:%08X)", (U32)(size_t)bufPool);
     if (!bufPool) return;   /* compatibility with free on NULL */
     for (u=0; utotalBuffers; u++) {
         DEBUGLOG(4, "free buffer %2u (address:%08X)", u, (U32)(size_t)bufPool->bTable[u].start);
         ZSTD_free(bufPool->bTable[u].start, bufPool->cMem);
     }
     ZSTD_pthread_mutex_destroy(&bufPool->poolMutex);
     ZSTD_free(bufPool, bufPool->cMem);
 }
 
 /* only works at initialization, not during compression */
 static size_t ZSTDMT_sizeof_bufferPool(ZSTDMT_bufferPool* bufPool)
 {
     size_t const poolSize = sizeof(*bufPool)
                             + (bufPool->totalBuffers - 1) * sizeof(buffer_t);
     unsigned u;
     size_t totalBufferSize = 0;
     ZSTD_pthread_mutex_lock(&bufPool->poolMutex);
     for (u=0; utotalBuffers; u++)
         totalBufferSize += bufPool->bTable[u].size;
     ZSTD_pthread_mutex_unlock(&bufPool->poolMutex);
 
     return poolSize + totalBufferSize;
 }
 
-static void ZSTDMT_setBufferSize(ZSTDMT_bufferPool* bufPool, size_t bSize)
+static void ZSTDMT_setBufferSize(ZSTDMT_bufferPool* const bufPool, size_t const bSize)
 {
+    ZSTD_pthread_mutex_lock(&bufPool->poolMutex);
+    DEBUGLOG(4, "ZSTDMT_setBufferSize: bSize = %u", (U32)bSize);
     bufPool->bufferSize = bSize;
+    ZSTD_pthread_mutex_unlock(&bufPool->poolMutex);
 }
 
 /** ZSTDMT_getBuffer() :
  *  assumption : bufPool must be valid */
 static buffer_t ZSTDMT_getBuffer(ZSTDMT_bufferPool* bufPool)
 {
     size_t const bSize = bufPool->bufferSize;
-    DEBUGLOG(5, "ZSTDMT_getBuffer");
+    DEBUGLOG(5, "ZSTDMT_getBuffer: bSize = %u", (U32)bufPool->bufferSize);
     ZSTD_pthread_mutex_lock(&bufPool->poolMutex);
     if (bufPool->nbBuffers) {   /* try to use an existing buffer */
         buffer_t const buf = bufPool->bTable[--(bufPool->nbBuffers)];
         size_t const availBufferSize = buf.size;
         bufPool->bTable[bufPool->nbBuffers] = g_nullBuffer;
-        if ((availBufferSize >= bSize) & (availBufferSize <= 10*bSize)) {
+        if ((availBufferSize >= bSize) & ((availBufferSize>>3) <= bSize)) {
             /* large enough, but not too much */
+            DEBUGLOG(5, "ZSTDMT_getBuffer: provide buffer %u of size %u",
+                        bufPool->nbBuffers, (U32)buf.size);
             ZSTD_pthread_mutex_unlock(&bufPool->poolMutex);
             return buf;
         }
         /* size conditions not respected : scratch this buffer, create new one */
-        DEBUGLOG(5, "existing buffer does not meet size conditions => freeing");
+        DEBUGLOG(5, "ZSTDMT_getBuffer: existing buffer does not meet size conditions => freeing");
         ZSTD_free(buf.start, bufPool->cMem);
     }
     ZSTD_pthread_mutex_unlock(&bufPool->poolMutex);
     /* create new buffer */
-    DEBUGLOG(5, "create a new buffer");
+    DEBUGLOG(5, "ZSTDMT_getBuffer: create a new buffer");
     {   buffer_t buffer;
         void* const start = ZSTD_malloc(bSize, bufPool->cMem);
         buffer.start = start;   /* note : start can be NULL if malloc fails ! */
         buffer.size = (start==NULL) ? 0 : bSize;
+        DEBUGLOG(5, "ZSTDMT_getBuffer: created buffer of size %u", (U32)bSize);
         return buffer;
     }
 }
 
 /* store buffer for later re-use, up to pool capacity */
 static void ZSTDMT_releaseBuffer(ZSTDMT_bufferPool* bufPool, buffer_t buf)
 {
     if (buf.start == NULL) return;   /* compatible with release on NULL */
     DEBUGLOG(5, "ZSTDMT_releaseBuffer");
     ZSTD_pthread_mutex_lock(&bufPool->poolMutex);
     if (bufPool->nbBuffers < bufPool->totalBuffers) {
         bufPool->bTable[bufPool->nbBuffers++] = buf;  /* stored for later use */
+        DEBUGLOG(5, "ZSTDMT_releaseBuffer: stored buffer of size %u in slot %u",
+                    (U32)buf.size, (U32)(bufPool->nbBuffers-1));
         ZSTD_pthread_mutex_unlock(&bufPool->poolMutex);
         return;
     }
     ZSTD_pthread_mutex_unlock(&bufPool->poolMutex);
     /* Reached bufferPool capacity (should not happen) */
-    DEBUGLOG(5, "buffer pool capacity reached => freeing ");
+    DEBUGLOG(5, "ZSTDMT_releaseBuffer: pool capacity reached => freeing ");
     ZSTD_free(buf.start, bufPool->cMem);
 }
 
 /* Sets parameters relevant to the compression job, initializing others to
  * default values. Notably, nbThreads should probably be zero. */
 static ZSTD_CCtx_params ZSTDMT_makeJobCCtxParams(ZSTD_CCtx_params const params)
 {
     ZSTD_CCtx_params jobParams;
     memset(&jobParams, 0, sizeof(jobParams));
 
     jobParams.cParams = params.cParams;
     jobParams.fParams = params.fParams;
     jobParams.compressionLevel = params.compressionLevel;
 
     jobParams.ldmParams = params.ldmParams;
     return jobParams;
 }
 
 /* =====   CCtx Pool   ===== */
 /* a single CCtx Pool can be invoked from multiple threads in parallel */
 
 typedef struct {
     ZSTD_pthread_mutex_t poolMutex;
     unsigned totalCCtx;
     unsigned availCCtx;
     ZSTD_customMem cMem;
     ZSTD_CCtx* cctx[1];   /* variable size */
 } ZSTDMT_CCtxPool;
 
 /* note : all CCtx borrowed from the pool should be released back to the pool _before_ freeing the pool */
 static void ZSTDMT_freeCCtxPool(ZSTDMT_CCtxPool* pool)
 {
     unsigned u;
     for (u=0; utotalCCtx; u++)
         ZSTD_freeCCtx(pool->cctx[u]);  /* note : compatible with free on NULL */
     ZSTD_pthread_mutex_destroy(&pool->poolMutex);
     ZSTD_free(pool, pool->cMem);
 }
 
 /* ZSTDMT_createCCtxPool() :
  * implies nbThreads >= 1 , checked by caller ZSTDMT_createCCtx() */
 static ZSTDMT_CCtxPool* ZSTDMT_createCCtxPool(unsigned nbThreads,
                                               ZSTD_customMem cMem)
 {
     ZSTDMT_CCtxPool* const cctxPool = (ZSTDMT_CCtxPool*) ZSTD_calloc(
         sizeof(ZSTDMT_CCtxPool) + (nbThreads-1)*sizeof(ZSTD_CCtx*), cMem);
     if (!cctxPool) return NULL;
     if (ZSTD_pthread_mutex_init(&cctxPool->poolMutex, NULL)) {
         ZSTD_free(cctxPool, cMem);
         return NULL;
     }
     cctxPool->cMem = cMem;
     cctxPool->totalCCtx = nbThreads;
     cctxPool->availCCtx = 1;   /* at least one cctx for single-thread mode */
     cctxPool->cctx[0] = ZSTD_createCCtx_advanced(cMem);
     if (!cctxPool->cctx[0]) { ZSTDMT_freeCCtxPool(cctxPool); return NULL; }
     DEBUGLOG(3, "cctxPool created, with %u threads", nbThreads);
     return cctxPool;
 }
 
 /* only works during initialization phase, not during compression */
 static size_t ZSTDMT_sizeof_CCtxPool(ZSTDMT_CCtxPool* cctxPool)
 {
     ZSTD_pthread_mutex_lock(&cctxPool->poolMutex);
     {   unsigned const nbThreads = cctxPool->totalCCtx;
         size_t const poolSize = sizeof(*cctxPool)
                                 + (nbThreads-1)*sizeof(ZSTD_CCtx*);
         unsigned u;
         size_t totalCCtxSize = 0;
         for (u=0; ucctx[u]);
         }
         ZSTD_pthread_mutex_unlock(&cctxPool->poolMutex);
         return poolSize + totalCCtxSize;
     }
 }
 
 static ZSTD_CCtx* ZSTDMT_getCCtx(ZSTDMT_CCtxPool* cctxPool)
 {
     DEBUGLOG(5, "ZSTDMT_getCCtx");
     ZSTD_pthread_mutex_lock(&cctxPool->poolMutex);
     if (cctxPool->availCCtx) {
         cctxPool->availCCtx--;
         {   ZSTD_CCtx* const cctx = cctxPool->cctx[cctxPool->availCCtx];
             ZSTD_pthread_mutex_unlock(&cctxPool->poolMutex);
             return cctx;
     }   }
     ZSTD_pthread_mutex_unlock(&cctxPool->poolMutex);
     DEBUGLOG(5, "create one more CCtx");
     return ZSTD_createCCtx_advanced(cctxPool->cMem);   /* note : can be NULL, when creation fails ! */
 }
 
 static void ZSTDMT_releaseCCtx(ZSTDMT_CCtxPool* pool, ZSTD_CCtx* cctx)
 {
     if (cctx==NULL) return;   /* compatibility with release on NULL */
     ZSTD_pthread_mutex_lock(&pool->poolMutex);
     if (pool->availCCtx < pool->totalCCtx)
         pool->cctx[pool->availCCtx++] = cctx;
     else {
         /* pool overflow : should not happen, since totalCCtx==nbThreads */
         DEBUGLOG(5, "CCtx pool overflow : free cctx");
         ZSTD_freeCCtx(cctx);
     }
     ZSTD_pthread_mutex_unlock(&pool->poolMutex);
 }
 
 
 /* =====   Thread worker   ===== */
 
 typedef struct {
     buffer_t src;
     const void* srcStart;
-    size_t   dictSize;
+    size_t   prefixSize;
     size_t   srcSize;
     buffer_t dstBuff;
     size_t   cSize;
     size_t   dstFlushed;
     unsigned firstChunk;
     unsigned lastChunk;
     unsigned jobCompleted;
     unsigned jobScanned;
     ZSTD_pthread_mutex_t* jobCompleted_mutex;
     ZSTD_pthread_cond_t* jobCompleted_cond;
     ZSTD_CCtx_params params;
     const ZSTD_CDict* cdict;
     ZSTDMT_CCtxPool* cctxPool;
     ZSTDMT_bufferPool* bufPool;
     unsigned long long fullFrameSize;
 } ZSTDMT_jobDescription;
 
 /* ZSTDMT_compressChunk() : POOL_function type */
 void ZSTDMT_compressChunk(void* jobDescription)
 {
     ZSTDMT_jobDescription* const job = (ZSTDMT_jobDescription*)jobDescription;
-    ZSTD_CCtx* cctx = ZSTDMT_getCCtx(job->cctxPool);
-    const void* const src = (const char*)job->srcStart + job->dictSize;
+    ZSTD_CCtx* const cctx = ZSTDMT_getCCtx(job->cctxPool);
+    const void* const src = (const char*)job->srcStart + job->prefixSize;
     buffer_t dstBuff = job->dstBuff;
-    DEBUGLOG(5, "job (first:%u) (last:%u) : dictSize %u, srcSize %u",
-                 job->firstChunk, job->lastChunk, (U32)job->dictSize, (U32)job->srcSize);
+    DEBUGLOG(5, "ZSTDMT_compressChunk: job (first:%u) (last:%u) : prefixSize %u, srcSize %u ",
+                 job->firstChunk, job->lastChunk, (U32)job->prefixSize, (U32)job->srcSize);
 
     if (cctx==NULL) {
         job->cSize = ERROR(memory_allocation);
         goto _endJob;
     }
 
     if (dstBuff.start == NULL) {
         dstBuff = ZSTDMT_getBuffer(job->bufPool);
         if (dstBuff.start==NULL) {
             job->cSize = ERROR(memory_allocation);
             goto _endJob;
         }
         job->dstBuff = dstBuff;
+        DEBUGLOG(5, "ZSTDMT_compressChunk: received dstBuff of size %u", (U32)dstBuff.size);
     }
 
-    if (job->cdict) {  /* should only happen for first segment */
-        size_t const initError = ZSTD_compressBegin_usingCDict_advanced(cctx, job->cdict, job->params.fParams, job->fullFrameSize);
-        DEBUGLOG(5, "using CDict");
+    if (job->cdict) {
+        size_t const initError = ZSTD_compressBegin_advanced_internal(cctx, NULL, 0, ZSTD_dm_auto, job->cdict, job->params, job->fullFrameSize);
+        DEBUGLOG(4, "ZSTDMT_compressChunk: init using CDict (windowLog=%u)", job->params.cParams.windowLog);
+        assert(job->firstChunk);  /* only allowed for first job */
         if (ZSTD_isError(initError)) { job->cSize = initError; goto _endJob; }
     } else {  /* srcStart points at reloaded section */
-        if (!job->firstChunk) job->params.fParams.contentSizeFlag = 0;  /* ensure no srcSize control */
-        { ZSTD_CCtx_params jobParams = job->params;
-          size_t const forceWindowError =
-              ZSTD_CCtxParam_setParameter(&jobParams, ZSTD_p_forceMaxWindow, !job->firstChunk);
-          /* Force loading dictionary in "content-only" mode (no header analysis) */
-          size_t const initError = ZSTD_compressBegin_advanced_internal(cctx, job->srcStart, job->dictSize, ZSTD_dm_rawContent, jobParams, job->fullFrameSize);
-            if (ZSTD_isError(initError) || ZSTD_isError(forceWindowError)) {
+        U64 const pledgedSrcSize = job->firstChunk ? job->fullFrameSize : ZSTD_CONTENTSIZE_UNKNOWN;
+        ZSTD_CCtx_params jobParams = job->params;   /* do not modify job->params ! copy it, modify the copy */
+        size_t const forceWindowError = ZSTD_CCtxParam_setParameter(&jobParams, ZSTD_p_forceMaxWindow, !job->firstChunk);
+        if (ZSTD_isError(forceWindowError)) {
+            DEBUGLOG(5, "ZSTD_CCtxParam_setParameter error : %s ", ZSTD_getErrorName(forceWindowError));
+            job->cSize = forceWindowError;
+            goto _endJob;
+        }
+        DEBUGLOG(5, "ZSTDMT_compressChunk: invoking ZSTD_compressBegin_advanced_internal with windowLog = %u ", jobParams.cParams.windowLog);
+        {   size_t const initError = ZSTD_compressBegin_advanced_internal(cctx,
+                                        job->srcStart, job->prefixSize, ZSTD_dm_rawContent, /* load dictionary in "content-only" mode (no header analysis) */
+                                        NULL,
+                                        jobParams, pledgedSrcSize);
+            if (ZSTD_isError(initError)) {
+                DEBUGLOG(5, "ZSTD_compressBegin_advanced_internal error : %s ", ZSTD_getErrorName(initError));
                 job->cSize = initError;
                 goto _endJob;
-            }
-    }   }
-    if (!job->firstChunk) {  /* flush and overwrite frame header when it's not first segment */
+        }   }
+    }
+    if (!job->firstChunk) {  /* flush and overwrite frame header when it's not first job */
         size_t const hSize = ZSTD_compressContinue(cctx, dstBuff.start, dstBuff.size, src, 0);
-        if (ZSTD_isError(hSize)) { job->cSize = hSize; goto _endJob; }
+        if (ZSTD_isError(hSize)) { job->cSize = hSize; /* save error code */ goto _endJob; }
         ZSTD_invalidateRepCodes(cctx);
     }
 
-    DEBUGLOG(5, "Compressing : ");
-    DEBUG_PRINTHEX(4, job->srcStart, 12);
+    DEBUGLOG(5, "Compressing into dstBuff of size %u", (U32)dstBuff.size);
+    DEBUG_PRINTHEX(6, job->srcStart, 12);
     job->cSize = (job->lastChunk) ?
                  ZSTD_compressEnd     (cctx, dstBuff.start, dstBuff.size, src, job->srcSize) :
                  ZSTD_compressContinue(cctx, dstBuff.start, dstBuff.size, src, job->srcSize);
-    DEBUGLOG(5, "compressed %u bytes into %u bytes   (first:%u) (last:%u)",
+    DEBUGLOG(5, "compressed %u bytes into %u bytes   (first:%u) (last:%u) ",
                 (unsigned)job->srcSize, (unsigned)job->cSize, job->firstChunk, job->lastChunk);
-    DEBUGLOG(5, "dstBuff.size : %u ; => %s", (U32)dstBuff.size, ZSTD_getErrorName(job->cSize));
+    DEBUGLOG(5, "dstBuff.size : %u ; => %s ", (U32)dstBuff.size, ZSTD_getErrorName(job->cSize));
 
 _endJob:
     ZSTDMT_releaseCCtx(job->cctxPool, cctx);
     ZSTDMT_releaseBuffer(job->bufPool, job->src);
     job->src = g_nullBuffer; job->srcStart = NULL;
     ZSTD_PTHREAD_MUTEX_LOCK(job->jobCompleted_mutex);
     job->jobCompleted = 1;
     job->jobScanned = 0;
     ZSTD_pthread_cond_signal(job->jobCompleted_cond);
     ZSTD_pthread_mutex_unlock(job->jobCompleted_mutex);
 }
 
 
 /* ------------------------------------------ */
 /* =====   Multi-threaded compression   ===== */
 /* ------------------------------------------ */
 
 typedef struct {
     buffer_t buffer;
     size_t filled;
 } inBuff_t;
 
 struct ZSTDMT_CCtx_s {
     POOL_ctx* factory;
     ZSTDMT_jobDescription* jobs;
     ZSTDMT_bufferPool* bufPool;
     ZSTDMT_CCtxPool* cctxPool;
     ZSTD_pthread_mutex_t jobCompleted_mutex;
     ZSTD_pthread_cond_t jobCompleted_cond;
+    ZSTD_CCtx_params params;
     size_t targetSectionSize;
     size_t inBuffSize;
     size_t dictSize;
     size_t targetDictSize;
     inBuff_t inBuff;
-    ZSTD_CCtx_params params;
     XXH64_state_t xxhState;
+    unsigned singleThreaded;
     unsigned jobIDMask;
     unsigned doneJobID;
     unsigned nextJobID;
     unsigned frameEnded;
     unsigned allJobsCompleted;
     unsigned long long frameContentSize;
     ZSTD_customMem cMem;
     ZSTD_CDict* cdictLocal;
     const ZSTD_CDict* cdict;
 };
 
 static ZSTDMT_jobDescription* ZSTDMT_allocJobsTable(U32* nbJobsPtr, ZSTD_customMem cMem)
 {
     U32 const nbJobsLog2 = ZSTD_highbit32(*nbJobsPtr) + 1;
     U32 const nbJobs = 1 << nbJobsLog2;
     *nbJobsPtr = nbJobs;
     return (ZSTDMT_jobDescription*) ZSTD_calloc(
                             nbJobs * sizeof(ZSTDMT_jobDescription), cMem);
 }
 
-/* Internal only */
-size_t ZSTDMT_initializeCCtxParameters(ZSTD_CCtx_params* params, unsigned nbThreads)
+/* ZSTDMT_CCtxParam_setNbThreads():
+ * Internal use only */
+size_t ZSTDMT_CCtxParam_setNbThreads(ZSTD_CCtx_params* params, unsigned nbThreads)
 {
+    if (nbThreads > ZSTDMT_NBTHREADS_MAX) nbThreads = ZSTDMT_NBTHREADS_MAX;
+    if (nbThreads < 1) nbThreads = 1;
     params->nbThreads = nbThreads;
     params->overlapSizeLog = ZSTDMT_OVERLAPLOG_DEFAULT;
     params->jobSize = 0;
-    return 0;
+    return nbThreads;
 }
 
+/* ZSTDMT_getNbThreads():
+ * @return nb threads currently active in mtctx.
+ * mtctx must be valid */
+size_t ZSTDMT_getNbThreads(const ZSTDMT_CCtx* mtctx)
+{
+    assert(mtctx != NULL);
+    return mtctx->params.nbThreads;
+}
+
 ZSTDMT_CCtx* ZSTDMT_createCCtx_advanced(unsigned nbThreads, ZSTD_customMem cMem)
 {
     ZSTDMT_CCtx* mtctx;
     U32 nbJobs = nbThreads + 2;
-    DEBUGLOG(3, "ZSTDMT_createCCtx_advanced");
+    DEBUGLOG(3, "ZSTDMT_createCCtx_advanced (nbThreads = %u)", nbThreads);
 
     if (nbThreads < 1) return NULL;
     nbThreads = MIN(nbThreads , ZSTDMT_NBTHREADS_MAX);
     if ((cMem.customAlloc!=NULL) ^ (cMem.customFree!=NULL))
         /* invalid custom allocator */
         return NULL;
 
     mtctx = (ZSTDMT_CCtx*) ZSTD_calloc(sizeof(ZSTDMT_CCtx), cMem);
     if (!mtctx) return NULL;
-    ZSTDMT_initializeCCtxParameters(&mtctx->params, nbThreads);
+    ZSTDMT_CCtxParam_setNbThreads(&mtctx->params, nbThreads);
     mtctx->cMem = cMem;
     mtctx->allJobsCompleted = 1;
     mtctx->factory = POOL_create_advanced(nbThreads, 0, cMem);
     mtctx->jobs = ZSTDMT_allocJobsTable(&nbJobs, cMem);
     mtctx->jobIDMask = nbJobs - 1;
     mtctx->bufPool = ZSTDMT_createBufferPool(nbThreads, cMem);
     mtctx->cctxPool = ZSTDMT_createCCtxPool(nbThreads, cMem);
     if (!mtctx->factory | !mtctx->jobs | !mtctx->bufPool | !mtctx->cctxPool) {
         ZSTDMT_freeCCtx(mtctx);
         return NULL;
     }
     if (ZSTD_pthread_mutex_init(&mtctx->jobCompleted_mutex, NULL)) {
         ZSTDMT_freeCCtx(mtctx);
         return NULL;
     }
     if (ZSTD_pthread_cond_init(&mtctx->jobCompleted_cond, NULL)) {
         ZSTDMT_freeCCtx(mtctx);
         return NULL;
     }
     DEBUGLOG(3, "mt_cctx created, for %u threads", nbThreads);
     return mtctx;
 }
 
 ZSTDMT_CCtx* ZSTDMT_createCCtx(unsigned nbThreads)
 {
     return ZSTDMT_createCCtx_advanced(nbThreads, ZSTD_defaultCMem);
 }
 
 /* ZSTDMT_releaseAllJobResources() :
  * note : ensure all workers are killed first ! */
 static void ZSTDMT_releaseAllJobResources(ZSTDMT_CCtx* mtctx)
 {
     unsigned jobID;
     DEBUGLOG(3, "ZSTDMT_releaseAllJobResources");
     for (jobID=0; jobID <= mtctx->jobIDMask; jobID++) {
         DEBUGLOG(4, "job%02u: release dst address %08X", jobID, (U32)(size_t)mtctx->jobs[jobID].dstBuff.start);
         ZSTDMT_releaseBuffer(mtctx->bufPool, mtctx->jobs[jobID].dstBuff);
         mtctx->jobs[jobID].dstBuff = g_nullBuffer;
         DEBUGLOG(4, "job%02u: release src address %08X", jobID, (U32)(size_t)mtctx->jobs[jobID].src.start);
         ZSTDMT_releaseBuffer(mtctx->bufPool, mtctx->jobs[jobID].src);
         mtctx->jobs[jobID].src = g_nullBuffer;
     }
     memset(mtctx->jobs, 0, (mtctx->jobIDMask+1)*sizeof(ZSTDMT_jobDescription));
     DEBUGLOG(4, "input: release address %08X", (U32)(size_t)mtctx->inBuff.buffer.start);
     ZSTDMT_releaseBuffer(mtctx->bufPool, mtctx->inBuff.buffer);
     mtctx->inBuff.buffer = g_nullBuffer;
     mtctx->allJobsCompleted = 1;
 }
 
 static void ZSTDMT_waitForAllJobsCompleted(ZSTDMT_CCtx* zcs)
 {
     DEBUGLOG(4, "ZSTDMT_waitForAllJobsCompleted");
     while (zcs->doneJobID < zcs->nextJobID) {
         unsigned const jobID = zcs->doneJobID & zcs->jobIDMask;
         ZSTD_PTHREAD_MUTEX_LOCK(&zcs->jobCompleted_mutex);
         while (zcs->jobs[jobID].jobCompleted==0) {
             DEBUGLOG(5, "waiting for jobCompleted signal from chunk %u", zcs->doneJobID);   /* we want to block when waiting for data to flush */
             ZSTD_pthread_cond_wait(&zcs->jobCompleted_cond, &zcs->jobCompleted_mutex);
         }
         ZSTD_pthread_mutex_unlock(&zcs->jobCompleted_mutex);
         zcs->doneJobID++;
     }
 }
 
 size_t ZSTDMT_freeCCtx(ZSTDMT_CCtx* mtctx)
 {
     if (mtctx==NULL) return 0;   /* compatible with free on NULL */
     POOL_free(mtctx->factory);   /* stop and free worker threads */
     ZSTDMT_releaseAllJobResources(mtctx);  /* release job resources into pools first */
     ZSTD_free(mtctx->jobs, mtctx->cMem);
     ZSTDMT_freeBufferPool(mtctx->bufPool);
     ZSTDMT_freeCCtxPool(mtctx->cctxPool);
     ZSTD_freeCDict(mtctx->cdictLocal);
     ZSTD_pthread_mutex_destroy(&mtctx->jobCompleted_mutex);
     ZSTD_pthread_cond_destroy(&mtctx->jobCompleted_cond);
     ZSTD_free(mtctx, mtctx->cMem);
     return 0;
 }
 
 size_t ZSTDMT_sizeof_CCtx(ZSTDMT_CCtx* mtctx)
 {
     if (mtctx == NULL) return 0;   /* supports sizeof NULL */
     return sizeof(*mtctx)
             + POOL_sizeof(mtctx->factory)
             + ZSTDMT_sizeof_bufferPool(mtctx->bufPool)
             + (mtctx->jobIDMask+1) * sizeof(ZSTDMT_jobDescription)
             + ZSTDMT_sizeof_CCtxPool(mtctx->cctxPool)
             + ZSTD_sizeof_CDict(mtctx->cdictLocal);
 }
 
 /* Internal only */
-size_t ZSTDMT_CCtxParam_setMTCtxParameter(
-    ZSTD_CCtx_params* params, ZSTDMT_parameter parameter, unsigned value) {
+size_t ZSTDMT_CCtxParam_setMTCtxParameter(ZSTD_CCtx_params* params,
+                                ZSTDMT_parameter parameter, unsigned value) {
+    DEBUGLOG(4, "ZSTDMT_CCtxParam_setMTCtxParameter");
     switch(parameter)
     {
-    case ZSTDMT_p_sectionSize :
+    case ZSTDMT_p_jobSize :
+        DEBUGLOG(4, "ZSTDMT_CCtxParam_setMTCtxParameter : set jobSize to %u", value);
+        if ( (value > 0)  /* value==0 => automatic job size */
+           & (value < ZSTDMT_JOBSIZE_MIN) )
+            value = ZSTDMT_JOBSIZE_MIN;
         params->jobSize = value;
-        return 0;
+        return value;
     case ZSTDMT_p_overlapSectionLog :
+        if (value > 9) value = 9;
         DEBUGLOG(4, "ZSTDMT_p_overlapSectionLog : %u", value);
         params->overlapSizeLog = (value >= 9) ? 9 : value;
-        return 0;
+        return value;
     default :
         return ERROR(parameter_unsupported);
     }
 }
 
 size_t ZSTDMT_setMTCtxParameter(ZSTDMT_CCtx* mtctx, ZSTDMT_parameter parameter, unsigned value)
 {
+    DEBUGLOG(4, "ZSTDMT_setMTCtxParameter");
     switch(parameter)
     {
-    case ZSTDMT_p_sectionSize :
+    case ZSTDMT_p_jobSize :
         return ZSTDMT_CCtxParam_setMTCtxParameter(&mtctx->params, parameter, value);
     case ZSTDMT_p_overlapSectionLog :
         return ZSTDMT_CCtxParam_setMTCtxParameter(&mtctx->params, parameter, value);
     default :
         return ERROR(parameter_unsupported);
     }
 }
 
 /* ------------------------------------------ */
 /* =====   Multi-threaded compression   ===== */
 /* ------------------------------------------ */
 
 static unsigned computeNbChunks(size_t srcSize, unsigned windowLog, unsigned nbThreads) {
     size_t const chunkSizeTarget = (size_t)1 << (windowLog + 2);
     size_t const chunkMaxSize = chunkSizeTarget << 2;
     size_t const passSizeMax = chunkMaxSize * nbThreads;
     unsigned const multiplier = (unsigned)(srcSize / passSizeMax) + 1;
     unsigned const nbChunksLarge = multiplier * nbThreads;
     unsigned const nbChunksMax = (unsigned)(srcSize / chunkSizeTarget) + 1;
     unsigned const nbChunksSmall = MIN(nbChunksMax, nbThreads);
     return (multiplier>1) ? nbChunksLarge : nbChunksSmall;
 }
 
 static size_t ZSTDMT_compress_advanced_internal(
                 ZSTDMT_CCtx* mtctx,
                 void* dst, size_t dstCapacity,
           const void* src, size_t srcSize,
           const ZSTD_CDict* cdict,
                 ZSTD_CCtx_params const params)
 {
     ZSTD_CCtx_params const jobParams = ZSTDMT_makeJobCCtxParams(params);
     unsigned const overlapRLog = (params.overlapSizeLog>9) ? 0 : 9-params.overlapSizeLog;
     size_t const overlapSize = (overlapRLog>=9) ? 0 : (size_t)1 << (params.cParams.windowLog - overlapRLog);
     unsigned nbChunks = computeNbChunks(srcSize, params.cParams.windowLog, params.nbThreads);
     size_t const proposedChunkSize = (srcSize + (nbChunks-1)) / nbChunks;
-    size_t const avgChunkSize = ((proposedChunkSize & 0x1FFFF) < 0x7FFF) ? proposedChunkSize + 0xFFFF : proposedChunkSize;   /* avoid too small last block */
+    size_t const avgChunkSize = (((proposedChunkSize-1) & 0x1FFFF) < 0x7FFF) ? proposedChunkSize + 0xFFFF : proposedChunkSize;   /* avoid too small last block */
     const char* const srcStart = (const char*)src;
     size_t remainingSrcSize = srcSize;
     unsigned const compressWithinDst = (dstCapacity >= ZSTD_compressBound(srcSize)) ? nbChunks : (unsigned)(dstCapacity / ZSTD_compressBound(avgChunkSize));  /* presumes avgChunkSize >= 256 KB, which should be the case */
     size_t frameStartPos = 0, dstBufferPos = 0;
     XXH64_state_t xxh64;
     assert(jobParams.nbThreads == 0);
     assert(mtctx->cctxPool->totalCCtx == params.nbThreads);
 
-    DEBUGLOG(4, "nbChunks  : %2u   (chunkSize : %u bytes)   ", nbChunks, (U32)avgChunkSize);
+    DEBUGLOG(4, "ZSTDMT_compress_advanced_internal: nbChunks=%2u (rawSize=%u bytes; fixedSize=%u)  ",
+                nbChunks, (U32)proposedChunkSize, (U32)avgChunkSize);
     if (nbChunks==1) {   /* fallback to single-thread mode */
         ZSTD_CCtx* const cctx = mtctx->cctxPool->cctx[0];
         if (cdict) return ZSTD_compress_usingCDict_advanced(cctx, dst, dstCapacity, src, srcSize, cdict, jobParams.fParams);
         return ZSTD_compress_advanced_internal(cctx, dst, dstCapacity, src, srcSize, NULL, 0, jobParams);
     }
     assert(avgChunkSize >= 256 KB);  /* condition for ZSTD_compressBound(A) + ZSTD_compressBound(B) <= ZSTD_compressBound(A+B), which is required for compressWithinDst */
     ZSTDMT_setBufferSize(mtctx->bufPool, ZSTD_compressBound(avgChunkSize) );
     XXH64_reset(&xxh64, 0);
 
     if (nbChunks > mtctx->jobIDMask+1) {  /* enlarge job table */
         U32 nbJobs = nbChunks;
         ZSTD_free(mtctx->jobs, mtctx->cMem);
         mtctx->jobIDMask = 0;
         mtctx->jobs = ZSTDMT_allocJobsTable(&nbJobs, mtctx->cMem);
         if (mtctx->jobs==NULL) return ERROR(memory_allocation);
         mtctx->jobIDMask = nbJobs - 1;
     }
 
     {   unsigned u;
         for (u=0; ujobs[u].src = g_nullBuffer;
             mtctx->jobs[u].srcStart = srcStart + frameStartPos - dictSize;
-            mtctx->jobs[u].dictSize = dictSize;
+            mtctx->jobs[u].prefixSize = dictSize;
             mtctx->jobs[u].srcSize = chunkSize;
-            mtctx->jobs[u].cdict = mtctx->nextJobID==0 ? cdict : NULL;
+            mtctx->jobs[u].cdict = (u==0) ? cdict : NULL;
             mtctx->jobs[u].fullFrameSize = srcSize;
             mtctx->jobs[u].params = jobParams;
             /* do not calculate checksum within sections, but write it in header for first section */
             if (u!=0) mtctx->jobs[u].params.fParams.checksumFlag = 0;
             mtctx->jobs[u].dstBuff = dstBuffer;
             mtctx->jobs[u].cctxPool = mtctx->cctxPool;
             mtctx->jobs[u].bufPool = mtctx->bufPool;
             mtctx->jobs[u].firstChunk = (u==0);
             mtctx->jobs[u].lastChunk = (u==nbChunks-1);
             mtctx->jobs[u].jobCompleted = 0;
             mtctx->jobs[u].jobCompleted_mutex = &mtctx->jobCompleted_mutex;
             mtctx->jobs[u].jobCompleted_cond = &mtctx->jobCompleted_cond;
 
             if (params.fParams.checksumFlag) {
                 XXH64_update(&xxh64, srcStart + frameStartPos, chunkSize);
             }
 
-            DEBUGLOG(5, "posting job %u   (%u bytes)", u, (U32)chunkSize);
+            DEBUGLOG(5, "ZSTDMT_compress_advanced_internal: posting job %u  (%u bytes)", u, (U32)chunkSize);
             DEBUG_PRINTHEX(6, mtctx->jobs[u].srcStart, 12);
             POOL_add(mtctx->factory, ZSTDMT_compressChunk, &mtctx->jobs[u]);
 
             frameStartPos += chunkSize;
             dstBufferPos += dstBufferCapacity;
             remainingSrcSize -= chunkSize;
     }   }
 
     /* collect result */
     {   size_t error = 0, dstPos = 0;
         unsigned chunkID;
         for (chunkID=0; chunkIDjobCompleted_mutex);
             while (mtctx->jobs[chunkID].jobCompleted==0) {
                 DEBUGLOG(5, "waiting for jobCompleted signal from chunk %u", chunkID);
                 ZSTD_pthread_cond_wait(&mtctx->jobCompleted_cond, &mtctx->jobCompleted_mutex);
             }
             ZSTD_pthread_mutex_unlock(&mtctx->jobCompleted_mutex);
             DEBUGLOG(5, "ready to write chunk %u ", chunkID);
 
             mtctx->jobs[chunkID].srcStart = NULL;
             {   size_t const cSize = mtctx->jobs[chunkID].cSize;
                 if (ZSTD_isError(cSize)) error = cSize;
                 if ((!error) && (dstPos + cSize > dstCapacity)) error = ERROR(dstSize_tooSmall);
                 if (chunkID) {   /* note : chunk 0 is written directly at dst, which is correct position */
                     if (!error)
                         memmove((char*)dst + dstPos, mtctx->jobs[chunkID].dstBuff.start, cSize);  /* may overlap when chunk compressed within dst */
                     if (chunkID >= compressWithinDst) {  /* chunk compressed into its own buffer, which must be released */
                         DEBUGLOG(5, "releasing buffer %u>=%u", chunkID, compressWithinDst);
                         ZSTDMT_releaseBuffer(mtctx->bufPool, mtctx->jobs[chunkID].dstBuff);
                 }   }
                 mtctx->jobs[chunkID].dstBuff = g_nullBuffer;
                 dstPos += cSize ;
             }
         }  /* for (chunkID=0; chunkID dstCapacity) {
                 error = ERROR(dstSize_tooSmall);
             } else {
                 DEBUGLOG(4, "writing checksum : %08X \n", checksum);
                 MEM_writeLE32((char*)dst + dstPos, checksum);
                 dstPos += 4;
         }   }
 
         if (!error) DEBUGLOG(4, "compressed size : %u  ", (U32)dstPos);
         return error ? error : dstPos;
     }
 }
 
 size_t ZSTDMT_compress_advanced(ZSTDMT_CCtx* mtctx,
                                void* dst, size_t dstCapacity,
                          const void* src, size_t srcSize,
                          const ZSTD_CDict* cdict,
                                ZSTD_parameters const params,
                                unsigned overlapLog)
 {
     ZSTD_CCtx_params cctxParams = mtctx->params;
     cctxParams.cParams = params.cParams;
     cctxParams.fParams = params.fParams;
     cctxParams.overlapSizeLog = overlapLog;
     return ZSTDMT_compress_advanced_internal(mtctx,
                                              dst, dstCapacity,
                                              src, srcSize,
                                              cdict, cctxParams);
 }
 
 
 size_t ZSTDMT_compressCCtx(ZSTDMT_CCtx* mtctx,
                            void* dst, size_t dstCapacity,
                      const void* src, size_t srcSize,
                            int compressionLevel)
 {
     U32 const overlapLog = (compressionLevel >= ZSTD_maxCLevel()) ? 9 : ZSTDMT_OVERLAPLOG_DEFAULT;
     ZSTD_parameters params = ZSTD_getParams(compressionLevel, srcSize, 0);
     params.fParams.contentSizeFlag = 1;
     return ZSTDMT_compress_advanced(mtctx, dst, dstCapacity, src, srcSize, NULL, params, overlapLog);
 }
 
 
 /* ====================================== */
 /* =======      Streaming API     ======= */
 /* ====================================== */
 
 size_t ZSTDMT_initCStream_internal(
         ZSTDMT_CCtx* zcs,
         const void* dict, size_t dictSize, ZSTD_dictMode_e dictMode,
         const ZSTD_CDict* cdict, ZSTD_CCtx_params params,
         unsigned long long pledgedSrcSize)
 {
-    DEBUGLOG(4, "ZSTDMT_initCStream_internal");
+    DEBUGLOG(4, "ZSTDMT_initCStream_internal (pledgedSrcSize=%u)", (U32)pledgedSrcSize);
     /* params are supposed to be fully validated at this point */
     assert(!ZSTD_isError(ZSTD_checkCParams(params.cParams)));
     assert(!((dict) && (cdict)));  /* either dict or cdict, not both */
     assert(zcs->cctxPool->totalCCtx == params.nbThreads);
+    zcs->singleThreaded = (params.nbThreads==1) | (pledgedSrcSize <= ZSTDMT_JOBSIZE_MIN);  /* do not trigger multi-threading when srcSize is too small */
 
-    if (params.nbThreads==1) {
+    if (zcs->singleThreaded) {
         ZSTD_CCtx_params const singleThreadParams = ZSTDMT_makeJobCCtxParams(params);
         DEBUGLOG(4, "single thread mode");
         assert(singleThreadParams.nbThreads == 0);
         return ZSTD_initCStream_internal(zcs->cctxPool->cctx[0],
                                          dict, dictSize, cdict,
                                          singleThreadParams, pledgedSrcSize);
     }
+    DEBUGLOG(4, "multi-threading mode (%u threads)", params.nbThreads);
 
     if (zcs->allJobsCompleted == 0) {   /* previous compression not correctly finished */
         ZSTDMT_waitForAllJobsCompleted(zcs);
         ZSTDMT_releaseAllJobResources(zcs);
         zcs->allJobsCompleted = 1;
     }
 
     zcs->params = params;
     zcs->frameContentSize = pledgedSrcSize;
     if (dict) {
-        DEBUGLOG(4,"cdictLocal: %08X", (U32)(size_t)zcs->cdictLocal);
         ZSTD_freeCDict(zcs->cdictLocal);
         zcs->cdictLocal = ZSTD_createCDict_advanced(dict, dictSize,
                                                     ZSTD_dlm_byCopy, dictMode, /* note : a loadPrefix becomes an internal CDict */
                                                     params.cParams, zcs->cMem);
         zcs->cdict = zcs->cdictLocal;
         if (zcs->cdictLocal == NULL) return ERROR(memory_allocation);
     } else {
-        DEBUGLOG(4,"cdictLocal: %08X", (U32)(size_t)zcs->cdictLocal);
         ZSTD_freeCDict(zcs->cdictLocal);
         zcs->cdictLocal = NULL;
         zcs->cdict = cdict;
     }
 
+    assert(params.overlapSizeLog <= 9);
     zcs->targetDictSize = (params.overlapSizeLog==0) ? 0 : (size_t)1 << (params.cParams.windowLog - (9 - params.overlapSizeLog));
-    DEBUGLOG(4, "overlapLog : %u ", params.overlapSizeLog);
-    DEBUGLOG(4, "overlap Size : %u KB", (U32)(zcs->targetDictSize>>10));
+    DEBUGLOG(4, "overlapLog=%u => %u KB", params.overlapSizeLog, (U32)(zcs->targetDictSize>>10));
     zcs->targetSectionSize = params.jobSize ? params.jobSize : (size_t)1 << (params.cParams.windowLog + 2);
-    zcs->targetSectionSize = MAX(ZSTDMT_SECTION_SIZE_MIN, zcs->targetSectionSize);
-    zcs->targetSectionSize = MAX(zcs->targetDictSize, zcs->targetSectionSize);
-    DEBUGLOG(4, "Section Size : %u KB", (U32)(zcs->targetSectionSize>>10));
+    if (zcs->targetSectionSize < ZSTDMT_JOBSIZE_MIN) zcs->targetSectionSize = ZSTDMT_JOBSIZE_MIN;
+    if (zcs->targetSectionSize < zcs->targetDictSize) zcs->targetSectionSize = zcs->targetDictSize;  /* job size must be >= overlap size */
+    DEBUGLOG(4, "Job Size : %u KB (note : set to %u)", (U32)(zcs->targetSectionSize>>10), params.jobSize);
     zcs->inBuffSize = zcs->targetDictSize + zcs->targetSectionSize;
+    DEBUGLOG(4, "inBuff Size : %u KB", (U32)(zcs->inBuffSize>>10));
     ZSTDMT_setBufferSize(zcs->bufPool, MAX(zcs->inBuffSize, ZSTD_compressBound(zcs->targetSectionSize)) );
     zcs->inBuff.buffer = g_nullBuffer;
     zcs->dictSize = 0;
     zcs->doneJobID = 0;
     zcs->nextJobID = 0;
     zcs->frameEnded = 0;
     zcs->allJobsCompleted = 0;
     if (params.fParams.checksumFlag) XXH64_reset(&zcs->xxhState, 0);
     return 0;
 }
 
 size_t ZSTDMT_initCStream_advanced(ZSTDMT_CCtx* mtctx,
                              const void* dict, size_t dictSize,
                                    ZSTD_parameters params,
                                    unsigned long long pledgedSrcSize)
 {
     ZSTD_CCtx_params cctxParams = mtctx->params;
-    DEBUGLOG(5, "ZSTDMT_initCStream_advanced");
+    DEBUGLOG(5, "ZSTDMT_initCStream_advanced (pledgedSrcSize=%u)", (U32)pledgedSrcSize);
     cctxParams.cParams = params.cParams;
     cctxParams.fParams = params.fParams;
     return ZSTDMT_initCStream_internal(mtctx, dict, dictSize, ZSTD_dm_auto, NULL,
                                        cctxParams, pledgedSrcSize);
 }
 
 size_t ZSTDMT_initCStream_usingCDict(ZSTDMT_CCtx* mtctx,
                                const ZSTD_CDict* cdict,
                                      ZSTD_frameParameters fParams,
                                      unsigned long long pledgedSrcSize)
 {
     ZSTD_CCtx_params cctxParams = mtctx->params;
     cctxParams.cParams = ZSTD_getCParamsFromCDict(cdict);
     cctxParams.fParams = fParams;
     if (cdict==NULL) return ERROR(dictionary_wrong);   /* method incompatible with NULL cdict */
     return ZSTDMT_initCStream_internal(mtctx, NULL, 0 /*dictSize*/, ZSTD_dm_auto, cdict,
                                        cctxParams, pledgedSrcSize);
 }
 
 
 /* ZSTDMT_resetCStream() :
- * pledgedSrcSize is optional and can be zero == unknown */
+ * pledgedSrcSize can be zero == unknown (for the time being)
+ * prefer using ZSTD_CONTENTSIZE_UNKNOWN,
+ * as `0` might mean "empty" in the future */
 size_t ZSTDMT_resetCStream(ZSTDMT_CCtx* zcs, unsigned long long pledgedSrcSize)
 {
+    if (!pledgedSrcSize) pledgedSrcSize = ZSTD_CONTENTSIZE_UNKNOWN;
     if (zcs->params.nbThreads==1)
         return ZSTD_resetCStream(zcs->cctxPool->cctx[0], pledgedSrcSize);
     return ZSTDMT_initCStream_internal(zcs, NULL, 0, ZSTD_dm_auto, 0, zcs->params,
                                        pledgedSrcSize);
 }
 
 size_t ZSTDMT_initCStream(ZSTDMT_CCtx* zcs, int compressionLevel) {
     ZSTD_parameters const params = ZSTD_getParams(compressionLevel, 0, 0);
     ZSTD_CCtx_params cctxParams = zcs->params;
     cctxParams.cParams = params.cParams;
     cctxParams.fParams = params.fParams;
-    return ZSTDMT_initCStream_internal(zcs, NULL, 0, ZSTD_dm_auto, NULL, cctxParams, 0);
+    return ZSTDMT_initCStream_internal(zcs, NULL, 0, ZSTD_dm_auto, NULL, cctxParams, ZSTD_CONTENTSIZE_UNKNOWN);
 }
 
 
 static size_t ZSTDMT_createCompressionJob(ZSTDMT_CCtx* zcs, size_t srcSize, unsigned endFrame)
 {
     unsigned const jobID = zcs->nextJobID & zcs->jobIDMask;
 
-    DEBUGLOG(4, "preparing job %u to compress %u bytes with %u preload ",
+    DEBUGLOG(5, "ZSTDMT_createCompressionJob: preparing job %u to compress %u bytes with %u preload ",
                 zcs->nextJobID, (U32)srcSize, (U32)zcs->dictSize);
     zcs->jobs[jobID].src = zcs->inBuff.buffer;
     zcs->jobs[jobID].srcStart = zcs->inBuff.buffer.start;
     zcs->jobs[jobID].srcSize = srcSize;
-    zcs->jobs[jobID].dictSize = zcs->dictSize;
+    zcs->jobs[jobID].prefixSize = zcs->dictSize;
     assert(zcs->inBuff.filled >= srcSize + zcs->dictSize);
     zcs->jobs[jobID].params = zcs->params;
     /* do not calculate checksum within sections, but write it in header for first section */
     if (zcs->nextJobID) zcs->jobs[jobID].params.fParams.checksumFlag = 0;
     zcs->jobs[jobID].cdict = zcs->nextJobID==0 ? zcs->cdict : NULL;
     zcs->jobs[jobID].fullFrameSize = zcs->frameContentSize;
     zcs->jobs[jobID].dstBuff = g_nullBuffer;
     zcs->jobs[jobID].cctxPool = zcs->cctxPool;
     zcs->jobs[jobID].bufPool = zcs->bufPool;
     zcs->jobs[jobID].firstChunk = (zcs->nextJobID==0);
     zcs->jobs[jobID].lastChunk = endFrame;
     zcs->jobs[jobID].jobCompleted = 0;
     zcs->jobs[jobID].dstFlushed = 0;
     zcs->jobs[jobID].jobCompleted_mutex = &zcs->jobCompleted_mutex;
     zcs->jobs[jobID].jobCompleted_cond = &zcs->jobCompleted_cond;
 
     if (zcs->params.fParams.checksumFlag)
         XXH64_update(&zcs->xxhState, (const char*)zcs->inBuff.buffer.start + zcs->dictSize, srcSize);
 
     /* get a new buffer for next input */
     if (!endFrame) {
         size_t const newDictSize = MIN(srcSize + zcs->dictSize, zcs->targetDictSize);
         zcs->inBuff.buffer = ZSTDMT_getBuffer(zcs->bufPool);
         if (zcs->inBuff.buffer.start == NULL) {   /* not enough memory to allocate next input buffer */
             zcs->jobs[jobID].jobCompleted = 1;
             zcs->nextJobID++;
             ZSTDMT_waitForAllJobsCompleted(zcs);
             ZSTDMT_releaseAllJobResources(zcs);
             return ERROR(memory_allocation);
         }
         zcs->inBuff.filled -= srcSize + zcs->dictSize - newDictSize;
         memmove(zcs->inBuff.buffer.start,
             (const char*)zcs->jobs[jobID].srcStart + zcs->dictSize + srcSize - newDictSize,
             zcs->inBuff.filled);
         zcs->dictSize = newDictSize;
     } else {   /* if (endFrame==1) */
         zcs->inBuff.buffer = g_nullBuffer;
         zcs->inBuff.filled = 0;
         zcs->dictSize = 0;
         zcs->frameEnded = 1;
         if (zcs->nextJobID == 0) {
             /* single chunk exception : checksum is calculated directly within worker thread */
             zcs->params.fParams.checksumFlag = 0;
     }   }
 
-    DEBUGLOG(4, "posting job %u : %u bytes  (end:%u) (note : doneJob = %u=>%u)",
+    DEBUGLOG(5, "ZSTDMT_createCompressionJob: posting job %u : %u bytes  (end:%u) (note : doneJob = %u=>%u)",
                 zcs->nextJobID,
                 (U32)zcs->jobs[jobID].srcSize,
                 zcs->jobs[jobID].lastChunk,
                 zcs->doneJobID,
                 zcs->doneJobID & zcs->jobIDMask);
     POOL_add(zcs->factory, ZSTDMT_compressChunk, &zcs->jobs[jobID]);   /* this call is blocking when thread worker pool is exhausted */
     zcs->nextJobID++;
     return 0;
 }
 
 
 /* ZSTDMT_flushNextJob() :
  * output : will be updated with amount of data flushed .
  * blockToFlush : if >0, the function will block and wait if there is no data available to flush .
  * @return : amount of data remaining within internal buffer, 1 if unknown but > 0, 0 if no more, or an error code */
 static size_t ZSTDMT_flushNextJob(ZSTDMT_CCtx* zcs, ZSTD_outBuffer* output, unsigned blockToFlush)
 {
     unsigned const wJobID = zcs->doneJobID & zcs->jobIDMask;
+    DEBUGLOG(5, "ZSTDMT_flushNextJob");
     if (zcs->doneJobID == zcs->nextJobID) return 0;   /* all flushed ! */
     ZSTD_PTHREAD_MUTEX_LOCK(&zcs->jobCompleted_mutex);
     while (zcs->jobs[wJobID].jobCompleted==0) {
         DEBUGLOG(5, "waiting for jobCompleted signal from job %u", zcs->doneJobID);
         if (!blockToFlush) { ZSTD_pthread_mutex_unlock(&zcs->jobCompleted_mutex); return 0; }  /* nothing ready to be flushed => skip */
         ZSTD_pthread_cond_wait(&zcs->jobCompleted_cond, &zcs->jobCompleted_mutex);  /* block when nothing available to flush */
     }
     ZSTD_pthread_mutex_unlock(&zcs->jobCompleted_mutex);
     /* compression job completed : output can be flushed */
     {   ZSTDMT_jobDescription job = zcs->jobs[wJobID];
         if (!job.jobScanned) {
             if (ZSTD_isError(job.cSize)) {
-                DEBUGLOG(5, "compression error detected ");
+                DEBUGLOG(5, "job %u : compression error detected : %s",
+                            zcs->doneJobID, ZSTD_getErrorName(job.cSize));
                 ZSTDMT_waitForAllJobsCompleted(zcs);
                 ZSTDMT_releaseAllJobResources(zcs);
                 return job.cSize;
             }
             DEBUGLOG(5, "zcs->params.fParams.checksumFlag : %u ", zcs->params.fParams.checksumFlag);
             if (zcs->params.fParams.checksumFlag) {
                 if (zcs->frameEnded && (zcs->doneJobID+1 == zcs->nextJobID)) {  /* write checksum at end of last section */
                     U32 const checksum = (U32)XXH64_digest(&zcs->xxhState);
                     DEBUGLOG(5, "writing checksum : %08X \n", checksum);
                     MEM_writeLE32((char*)job.dstBuff.start + job.cSize, checksum);
                     job.cSize += 4;
                     zcs->jobs[wJobID].cSize += 4;
             }   }
             zcs->jobs[wJobID].jobScanned = 1;
         }
         {   size_t const toWrite = MIN(job.cSize - job.dstFlushed, output->size - output->pos);
             DEBUGLOG(5, "Flushing %u bytes from job %u ", (U32)toWrite, zcs->doneJobID);
             memcpy((char*)output->dst + output->pos, (const char*)job.dstBuff.start + job.dstFlushed, toWrite);
             output->pos += toWrite;
             job.dstFlushed += toWrite;
         }
         if (job.dstFlushed == job.cSize) {   /* output buffer fully flushed => move to next one */
             ZSTDMT_releaseBuffer(zcs->bufPool, job.dstBuff);
             zcs->jobs[wJobID].dstBuff = g_nullBuffer;
             zcs->jobs[wJobID].jobCompleted = 0;
             zcs->doneJobID++;
         } else {
             zcs->jobs[wJobID].dstFlushed = job.dstFlushed;
         }
         /* return value : how many bytes left in buffer ; fake it to 1 if unknown but >0 */
         if (job.cSize > job.dstFlushed) return (job.cSize - job.dstFlushed);
         if (zcs->doneJobID < zcs->nextJobID) return 1;   /* still some buffer to flush */
         zcs->allJobsCompleted = zcs->frameEnded;   /* frame completed and entirely flushed */
         return 0;   /* everything flushed */
 }   }
 
 
 /** ZSTDMT_compressStream_generic() :
  *  internal use only - exposed to be invoked from zstd_compress.c
  *  assumption : output and input are valid (pos <= size)
  * @return : minimum amount of data remaining to flush, 0 if none */
 size_t ZSTDMT_compressStream_generic(ZSTDMT_CCtx* mtctx,
                                      ZSTD_outBuffer* output,
                                      ZSTD_inBuffer* input,
                                      ZSTD_EndDirective endOp)
 {
     size_t const newJobThreshold = mtctx->dictSize + mtctx->targetSectionSize;
     unsigned forwardInputProgress = 0;
+    DEBUGLOG(5, "ZSTDMT_compressStream_generic ");
     assert(output->pos <= output->size);
     assert(input->pos  <= input->size);
+
+    if (mtctx->singleThreaded) {  /* delegate to single-thread (synchronous) */
+        return ZSTD_compressStream_generic(mtctx->cctxPool->cctx[0], output, input, endOp);
+    }
+
     if ((mtctx->frameEnded) && (endOp==ZSTD_e_continue)) {
         /* current frame being ended. Only flush/end are allowed */
         return ERROR(stage_wrong);
     }
-    if (mtctx->params.nbThreads==1) {  /* delegate to single-thread (synchronous) */
-        return ZSTD_compressStream_generic(mtctx->cctxPool->cctx[0], output, input, endOp);
-    }
 
     /* single-pass shortcut (note : synchronous-mode) */
     if ( (mtctx->nextJobID == 0)     /* just started */
       && (mtctx->inBuff.filled == 0) /* nothing buffered */
       && (endOp == ZSTD_e_end)       /* end order */
       && (output->size - output->pos >= ZSTD_compressBound(input->size - input->pos)) ) { /* enough room */
         size_t const cSize = ZSTDMT_compress_advanced_internal(mtctx,
                 (char*)output->dst + output->pos, output->size - output->pos,
                 (const char*)input->src + input->pos, input->size - input->pos,
                 mtctx->cdict, mtctx->params);
         if (ZSTD_isError(cSize)) return cSize;
         input->pos = input->size;
         output->pos += cSize;
         ZSTDMT_releaseBuffer(mtctx->bufPool, mtctx->inBuff.buffer);  /* was allocated in initStream */
         mtctx->allJobsCompleted = 1;
         mtctx->frameEnded = 1;
         return 0;
     }
 
     /* fill input buffer */
     if (input->size > input->pos) {   /* support NULL input */
         if (mtctx->inBuff.buffer.start == NULL) {
             mtctx->inBuff.buffer = ZSTDMT_getBuffer(mtctx->bufPool);  /* note : may fail, in which case, no forward input progress */
             mtctx->inBuff.filled = 0;
         }
         if (mtctx->inBuff.buffer.start) {
             size_t const toLoad = MIN(input->size - input->pos, mtctx->inBuffSize - mtctx->inBuff.filled);
             DEBUGLOG(5, "inBuff:%08X;  inBuffSize=%u;  ToCopy=%u", (U32)(size_t)mtctx->inBuff.buffer.start, (U32)mtctx->inBuffSize, (U32)toLoad);
             memcpy((char*)mtctx->inBuff.buffer.start + mtctx->inBuff.filled, (const char*)input->src + input->pos, toLoad);
             input->pos += toLoad;
             mtctx->inBuff.filled += toLoad;
             forwardInputProgress = toLoad>0;
     }   }
 
     if ( (mtctx->inBuff.filled >= newJobThreshold)  /* filled enough : let's compress */
       && (mtctx->nextJobID <= mtctx->doneJobID + mtctx->jobIDMask) ) {   /* avoid overwriting job round buffer */
         CHECK_F( ZSTDMT_createCompressionJob(mtctx, mtctx->targetSectionSize, 0 /* endFrame */) );
     }
 
     /* check for potential compressed data ready to be flushed */
     CHECK_F( ZSTDMT_flushNextJob(mtctx, output, !forwardInputProgress /* blockToFlush */) ); /* block if there was no forward input progress */
 
     if (input->pos < input->size)  /* input not consumed : do not flush yet */
         endOp = ZSTD_e_continue;
 
     switch(endOp)
     {
         case ZSTD_e_flush:
             return ZSTDMT_flushStream(mtctx, output);
         case ZSTD_e_end:
             return ZSTDMT_endStream(mtctx, output);
         case ZSTD_e_continue:
             return 1;
         default:
             return ERROR(GENERIC);   /* invalid endDirective */
     }
 }
 
 
 size_t ZSTDMT_compressStream(ZSTDMT_CCtx* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
 {
     CHECK_F( ZSTDMT_compressStream_generic(zcs, output, input, ZSTD_e_continue) );
 
     /* recommended next input size : fill current input buffer */
     return zcs->inBuffSize - zcs->inBuff.filled;   /* note : could be zero when input buffer is fully filled and no more availability to create new job */
 }
 
 
-static size_t ZSTDMT_flushStream_internal(ZSTDMT_CCtx* zcs, ZSTD_outBuffer* output, unsigned endFrame)
+static size_t ZSTDMT_flushStream_internal(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* output, unsigned endFrame)
 {
-    size_t const srcSize = zcs->inBuff.filled - zcs->dictSize;
+    size_t const srcSize = mtctx->inBuff.filled - mtctx->dictSize;
+    DEBUGLOG(5, "ZSTDMT_flushStream_internal");
 
-    if ( ((srcSize > 0) || (endFrame && !zcs->frameEnded))
-       && (zcs->nextJobID <= zcs->doneJobID + zcs->jobIDMask) ) {
-        CHECK_F( ZSTDMT_createCompressionJob(zcs, srcSize, endFrame) );
+    if ( ((srcSize > 0) || (endFrame && !mtctx->frameEnded))
+       && (mtctx->nextJobID <= mtctx->doneJobID + mtctx->jobIDMask) ) {
+           DEBUGLOG(5, "ZSTDMT_flushStream_internal : create a new job");
+        CHECK_F( ZSTDMT_createCompressionJob(mtctx, srcSize, endFrame) );
     }
 
     /* check if there is any data available to flush */
-    return ZSTDMT_flushNextJob(zcs, output, 1 /* blockToFlush */);
+    return ZSTDMT_flushNextJob(mtctx, output, 1 /* blockToFlush */);
 }
 
 
-size_t ZSTDMT_flushStream(ZSTDMT_CCtx* zcs, ZSTD_outBuffer* output)
+size_t ZSTDMT_flushStream(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* output)
 {
     DEBUGLOG(5, "ZSTDMT_flushStream");
-    if (zcs->params.nbThreads==1)
-        return ZSTD_flushStream(zcs->cctxPool->cctx[0], output);
-    return ZSTDMT_flushStream_internal(zcs, output, 0 /* endFrame */);
+    if (mtctx->singleThreaded)
+        return ZSTD_flushStream(mtctx->cctxPool->cctx[0], output);
+    return ZSTDMT_flushStream_internal(mtctx, output, 0 /* endFrame */);
 }
 
-size_t ZSTDMT_endStream(ZSTDMT_CCtx* zcs, ZSTD_outBuffer* output)
+size_t ZSTDMT_endStream(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* output)
 {
     DEBUGLOG(4, "ZSTDMT_endStream");
-    if (zcs->params.nbThreads==1)
-        return ZSTD_endStream(zcs->cctxPool->cctx[0], output);
-    return ZSTDMT_flushStream_internal(zcs, output, 1 /* endFrame */);
+    if (mtctx->singleThreaded)
+        return ZSTD_endStream(mtctx->cctxPool->cctx[0], output);
+    return ZSTDMT_flushStream_internal(mtctx, output, 1 /* endFrame */);
 }
Index: head/sys/contrib/zstd/lib/compress/zstdmt_compress.h
===================================================================
--- head/sys/contrib/zstd/lib/compress/zstdmt_compress.h	(revision 330893)
+++ head/sys/contrib/zstd/lib/compress/zstdmt_compress.h	(revision 330894)
@@ -1,132 +1,140 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
  #ifndef ZSTDMT_COMPRESS_H
  #define ZSTDMT_COMPRESS_H
 
  #if defined (__cplusplus)
  extern "C" {
  #endif
 
 
 /* Note : This is an internal API.
  *        Some methods are still exposed (ZSTDLIB_API),
  *        because it used to be the only way to invoke MT compression.
  *        Now, it's recommended to use ZSTD_compress_generic() instead.
  *        These methods will stop being exposed in a future version */
 
 /* ===   Dependencies   === */
 #include                 /* size_t */
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_parameters */
 #include "zstd.h"            /* ZSTD_inBuffer, ZSTD_outBuffer, ZSTDLIB_API */
 
 
 /* ===   Memory management   === */
 typedef struct ZSTDMT_CCtx_s ZSTDMT_CCtx;
 ZSTDLIB_API ZSTDMT_CCtx* ZSTDMT_createCCtx(unsigned nbThreads);
 ZSTDLIB_API ZSTDMT_CCtx* ZSTDMT_createCCtx_advanced(unsigned nbThreads,
                                                     ZSTD_customMem cMem);
 ZSTDLIB_API size_t ZSTDMT_freeCCtx(ZSTDMT_CCtx* mtctx);
 
 ZSTDLIB_API size_t ZSTDMT_sizeof_CCtx(ZSTDMT_CCtx* mtctx);
 
 
 /* ===   Simple buffer-to-butter one-pass function   === */
 
 ZSTDLIB_API size_t ZSTDMT_compressCCtx(ZSTDMT_CCtx* mtctx,
                                        void* dst, size_t dstCapacity,
                                  const void* src, size_t srcSize,
                                        int compressionLevel);
 
 
 
 /* ===   Streaming functions   === */
 
 ZSTDLIB_API size_t ZSTDMT_initCStream(ZSTDMT_CCtx* mtctx, int compressionLevel);
-ZSTDLIB_API size_t ZSTDMT_resetCStream(ZSTDMT_CCtx* mtctx, unsigned long long pledgedSrcSize);    /**< pledgedSrcSize is optional and can be zero == unknown */
+ZSTDLIB_API size_t ZSTDMT_resetCStream(ZSTDMT_CCtx* mtctx, unsigned long long pledgedSrcSize);  /**< if srcSize is not known at reset time, use ZSTD_CONTENTSIZE_UNKNOWN. Note: for compatibility with older programs, 0 means the same as ZSTD_CONTENTSIZE_UNKNOWN, but it may change in the future, to mean "empty" */
 
 ZSTDLIB_API size_t ZSTDMT_compressStream(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
 
 ZSTDLIB_API size_t ZSTDMT_flushStream(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* output);   /**< @return : 0 == all flushed; >0 : still some data to be flushed; or an error code (ZSTD_isError()) */
 ZSTDLIB_API size_t ZSTDMT_endStream(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* output);     /**< @return : 0 == all flushed; >0 : still some data to be flushed; or an error code (ZSTD_isError()) */
 
 
 /* ===   Advanced functions and parameters  === */
 
-#ifndef ZSTDMT_SECTION_SIZE_MIN
-#  define ZSTDMT_SECTION_SIZE_MIN (1U << 20)   /* 1 MB - Minimum size of each compression job */
+#ifndef ZSTDMT_JOBSIZE_MIN
+#  define ZSTDMT_JOBSIZE_MIN (1U << 20)   /* 1 MB - Minimum size of each compression job */
 #endif
 
 ZSTDLIB_API size_t ZSTDMT_compress_advanced(ZSTDMT_CCtx* mtctx,
                                            void* dst, size_t dstCapacity,
                                      const void* src, size_t srcSize,
                                      const ZSTD_CDict* cdict,
                                            ZSTD_parameters const params,
                                            unsigned overlapLog);
 
 ZSTDLIB_API size_t ZSTDMT_initCStream_advanced(ZSTDMT_CCtx* mtctx,
                                         const void* dict, size_t dictSize,   /* dict can be released after init, a local copy is preserved within zcs */
                                         ZSTD_parameters params,
                                         unsigned long long pledgedSrcSize);  /* pledgedSrcSize is optional and can be zero == unknown */
 
 ZSTDLIB_API size_t ZSTDMT_initCStream_usingCDict(ZSTDMT_CCtx* mtctx,
                                         const ZSTD_CDict* cdict,
                                         ZSTD_frameParameters fparams,
                                         unsigned long long pledgedSrcSize);  /* note : zero means empty */
 
 /* ZSTDMT_parameter :
  * List of parameters that can be set using ZSTDMT_setMTCtxParameter() */
 typedef enum {
-    ZSTDMT_p_sectionSize,        /* size of input "section". Each section is compressed in parallel. 0 means default, which is dynamically determined within compression functions */
-    ZSTDMT_p_overlapSectionLog   /* Log of overlapped section; 0 == no overlap, 6(default) == use 1/8th of window, >=9 == use full window */
+    ZSTDMT_p_jobSize,           /* Each job is compressed in parallel. By default, this value is dynamically determined depending on compression parameters. Can be set explicitly here. */
+    ZSTDMT_p_overlapSectionLog  /* Each job may reload a part of previous job to enhance compressionr ratio; 0 == no overlap, 6(default) == use 1/8th of window, >=9 == use full window */
 } ZSTDMT_parameter;
 
 /* ZSTDMT_setMTCtxParameter() :
  * allow setting individual parameters, one at a time, among a list of enums defined in ZSTDMT_parameter.
- * The function must be called typically after ZSTD_createCCtx().
+ * The function must be called typically after ZSTD_createCCtx() but __before ZSTDMT_init*() !__
  * Parameters not explicitly reset by ZSTDMT_init*() remain the same in consecutive compression sessions.
  * @return : 0, or an error code (which can be tested using ZSTD_isError()) */
 ZSTDLIB_API size_t ZSTDMT_setMTCtxParameter(ZSTDMT_CCtx* mtctx, ZSTDMT_parameter parameter, unsigned value);
 
 
 /*! ZSTDMT_compressStream_generic() :
  *  Combines ZSTDMT_compressStream() with ZSTDMT_flushStream() or ZSTDMT_endStream()
  *  depending on flush directive.
  * @return : minimum amount of data still to be flushed
  *           0 if fully flushed
  *           or an error code */
 ZSTDLIB_API size_t ZSTDMT_compressStream_generic(ZSTDMT_CCtx* mtctx,
                                                 ZSTD_outBuffer* output,
                                                 ZSTD_inBuffer* input,
                                                 ZSTD_EndDirective endOp);
 
 
 /* ===   Private definitions; never ever use directly  === */
 
 size_t ZSTDMT_CCtxParam_setMTCtxParameter(ZSTD_CCtx_params* params, ZSTDMT_parameter parameter, unsigned value);
 
-size_t ZSTDMT_initializeCCtxParameters(ZSTD_CCtx_params* params, unsigned nbThreads);
+/* ZSTDMT_CCtxParam_setNbThreads()
+ * Set nbThreads, and clamp it correctly,
+ * also reset jobSize and overlapLog */
+size_t ZSTDMT_CCtxParam_setNbThreads(ZSTD_CCtx_params* params, unsigned nbThreads);
+
+/* ZSTDMT_getNbThreads():
+ * @return nb threads currently active in mtctx.
+ * mtctx must be valid */
+size_t ZSTDMT_getNbThreads(const ZSTDMT_CCtx* mtctx);
 
 /*! ZSTDMT_initCStream_internal() :
  *  Private use only. Init streaming operation.
  *  expects params to be valid.
  *  must receive dict, or cdict, or none, but not both.
  *  @return : 0, or an error code */
 size_t ZSTDMT_initCStream_internal(ZSTDMT_CCtx* zcs,
                     const void* dict, size_t dictSize, ZSTD_dictMode_e dictMode,
                     const ZSTD_CDict* cdict,
                     ZSTD_CCtx_params params, unsigned long long pledgedSrcSize);
 
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif   /* ZSTDMT_COMPRESS_H */
Index: head/sys/contrib/zstd/lib/decompress/zstd_decompress.c
===================================================================
--- head/sys/contrib/zstd/lib/decompress/zstd_decompress.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/decompress/zstd_decompress.c	(revision 330894)
@@ -1,2655 +1,2665 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 
 /* ***************************************************************
 *  Tuning parameters
 *****************************************************************/
 /*!
  * HEAPMODE :
  * Select how default decompression function ZSTD_decompress() will allocate memory,
  * in memory stack (0), or in memory heap (1, requires malloc())
  */
 #ifndef ZSTD_HEAPMODE
 #  define ZSTD_HEAPMODE 1
 #endif
 
 /*!
 *  LEGACY_SUPPORT :
 *  if set to 1, ZSTD_decompress() can decode older formats (v0.1+)
 */
 #ifndef ZSTD_LEGACY_SUPPORT
 #  define ZSTD_LEGACY_SUPPORT 0
 #endif
 
 /*!
 *  MAXWINDOWSIZE_DEFAULT :
 *  maximum window size accepted by DStream, by default.
 *  Frames requiring more memory will be rejected.
 */
 #ifndef ZSTD_MAXWINDOWSIZE_DEFAULT
 #  define ZSTD_MAXWINDOWSIZE_DEFAULT (((U32)1 << ZSTD_WINDOWLOG_DEFAULTMAX) + 1)
 #endif
 
 
 /*-*******************************************************
 *  Dependencies
 *********************************************************/
 #include       /* memcpy, memmove, memset */
 #include "mem.h"         /* low level memory routines */
 #define FSE_STATIC_LINKING_ONLY
 #include "fse.h"
 #define HUF_STATIC_LINKING_ONLY
 #include "huf.h"
 #include "zstd_internal.h"
 
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
 #  include "zstd_legacy.h"
 #endif
 
 
 /*-*************************************
 *  Errors
 ***************************************/
 #define ZSTD_isError ERR_isError   /* for inlining */
 #define FSE_isError  ERR_isError
 #define HUF_isError  ERR_isError
 
 
 /*_*******************************************************
 *  Memory operations
 **********************************************************/
 static void ZSTD_copy4(void* dst, const void* src) { memcpy(dst, src, 4); }
 
 
 /*-*************************************************************
 *   Context management
 ***************************************************************/
 typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader,
                ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock,
                ZSTDds_decompressLastBlock, ZSTDds_checkChecksum,
                ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage;
 
 typedef enum { zdss_init=0, zdss_loadHeader,
                zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
 
 typedef struct {
     FSE_DTable LLTable[FSE_DTABLE_SIZE_U32(LLFSELog)];
     FSE_DTable OFTable[FSE_DTABLE_SIZE_U32(OffFSELog)];
     FSE_DTable MLTable[FSE_DTABLE_SIZE_U32(MLFSELog)];
     HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)];  /* can accommodate HUF_decompress4X */
     U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];
     U32 rep[ZSTD_REP_NUM];
 } ZSTD_entropyDTables_t;
 
 struct ZSTD_DCtx_s
 {
     const FSE_DTable* LLTptr;
     const FSE_DTable* MLTptr;
     const FSE_DTable* OFTptr;
     const HUF_DTable* HUFptr;
     ZSTD_entropyDTables_t entropy;
     const void* previousDstEnd;   /* detect continuity */
     const void* base;             /* start of current segment */
     const void* vBase;            /* virtual start of previous segment if it was just before current one */
     const void* dictEnd;          /* end of previous segment */
     size_t expected;
     ZSTD_frameHeader fParams;
     U64 decodedSize;
     blockType_e bType;            /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */
     ZSTD_dStage stage;
     U32 litEntropy;
     U32 fseEntropy;
     XXH64_state_t xxhState;
     size_t headerSize;
     U32 dictID;
     ZSTD_format_e format;
     const BYTE* litPtr;
     ZSTD_customMem customMem;
     size_t litSize;
     size_t rleSize;
     size_t staticSize;
 
     /* streaming */
     ZSTD_DDict* ddictLocal;
     const ZSTD_DDict* ddict;
     ZSTD_dStreamStage streamStage;
     char*  inBuff;
     size_t inBuffSize;
     size_t inPos;
     size_t maxWindowSize;
     char*  outBuff;
     size_t outBuffSize;
     size_t outStart;
     size_t outEnd;
     size_t lhSize;
     void* legacyContext;
     U32 previousLegacyVersion;
     U32 legacyVersion;
     U32 hostageByte;
 
     /* workspace */
     BYTE litBuffer[ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH];
     BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
 };  /* typedef'd to ZSTD_DCtx within "zstd.h" */
 
 size_t ZSTD_sizeof_DCtx (const ZSTD_DCtx* dctx)
 {
     if (dctx==NULL) return 0;   /* support sizeof NULL */
     return sizeof(*dctx)
            + ZSTD_sizeof_DDict(dctx->ddictLocal)
            + dctx->inBuffSize + dctx->outBuffSize;
 }
 
 size_t ZSTD_estimateDCtxSize(void) { return sizeof(ZSTD_DCtx); }
 
 
 static size_t ZSTD_startingInputLength(ZSTD_format_e format)
 {
     size_t const startingInputLength = (format==ZSTD_f_zstd1_magicless) ?
                     ZSTD_frameHeaderSize_prefix - ZSTD_frameIdSize :
                     ZSTD_frameHeaderSize_prefix;
     ZSTD_STATIC_ASSERT(ZSTD_FRAMEHEADERSIZE_PREFIX >= ZSTD_FRAMEIDSIZE);
     /* only supports formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless */
     assert( (format == ZSTD_f_zstd1) || (format == ZSTD_f_zstd1_magicless) );
     return startingInputLength;
 }
 
 static void ZSTD_initDCtx_internal(ZSTD_DCtx* dctx)
 {
     dctx->format = ZSTD_f_zstd1;  /* ZSTD_decompressBegin() invokes ZSTD_startingInputLength() with argument dctx->format */
     dctx->staticSize  = 0;
     dctx->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT;
     dctx->ddict       = NULL;
     dctx->ddictLocal  = NULL;
     dctx->inBuff      = NULL;
     dctx->inBuffSize  = 0;
     dctx->outBuffSize = 0;
     dctx->streamStage = zdss_init;
 }
 
 ZSTD_DCtx* ZSTD_initStaticDCtx(void *workspace, size_t workspaceSize)
 {
     ZSTD_DCtx* const dctx = (ZSTD_DCtx*) workspace;
 
     if ((size_t)workspace & 7) return NULL;  /* 8-aligned */
     if (workspaceSize < sizeof(ZSTD_DCtx)) return NULL;  /* minimum size */
 
     ZSTD_initDCtx_internal(dctx);
     dctx->staticSize = workspaceSize;
     dctx->inBuff = (char*)(dctx+1);
     return dctx;
 }
 
 ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem)
 {
     if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
 
     {   ZSTD_DCtx* const dctx = (ZSTD_DCtx*)ZSTD_malloc(sizeof(*dctx), customMem);
         if (!dctx) return NULL;
         dctx->customMem = customMem;
         dctx->legacyContext = NULL;
         dctx->previousLegacyVersion = 0;
         ZSTD_initDCtx_internal(dctx);
         return dctx;
     }
 }
 
 ZSTD_DCtx* ZSTD_createDCtx(void)
 {
     return ZSTD_createDCtx_advanced(ZSTD_defaultCMem);
 }
 
 size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx)
 {
     if (dctx==NULL) return 0;   /* support free on NULL */
     if (dctx->staticSize) return ERROR(memory_allocation);   /* not compatible with static DCtx */
     {   ZSTD_customMem const cMem = dctx->customMem;
         ZSTD_freeDDict(dctx->ddictLocal);
         dctx->ddictLocal = NULL;
         ZSTD_free(dctx->inBuff, cMem);
         dctx->inBuff = NULL;
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
         if (dctx->legacyContext)
             ZSTD_freeLegacyStreamContext(dctx->legacyContext, dctx->previousLegacyVersion);
 #endif
         ZSTD_free(dctx, cMem);
         return 0;
     }
 }
 
 /* no longer useful */
 void ZSTD_copyDCtx(ZSTD_DCtx* dstDCtx, const ZSTD_DCtx* srcDCtx)
 {
     size_t const toCopy = (size_t)((char*)(&dstDCtx->inBuff) - (char*)dstDCtx);
     memcpy(dstDCtx, srcDCtx, toCopy);  /* no need to copy workspace */
 }
 
 
 /*-*************************************************************
 *   Decompression section
 ***************************************************************/
 
 /*! ZSTD_isFrame() :
  *  Tells if the content of `buffer` starts with a valid Frame Identifier.
  *  Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0.
  *  Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled.
  *  Note 3 : Skippable Frame Identifiers are considered valid. */
 unsigned ZSTD_isFrame(const void* buffer, size_t size)
 {
     if (size < ZSTD_frameIdSize) return 0;
     {   U32 const magic = MEM_readLE32(buffer);
         if (magic == ZSTD_MAGICNUMBER) return 1;
         if ((magic & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) return 1;
     }
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
     if (ZSTD_isLegacy(buffer, size)) return 1;
 #endif
     return 0;
 }
 
 /** ZSTD_frameHeaderSize_internal() :
  *  srcSize must be large enough to reach header size fields.
  *  note : only works for formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless
  * @return : size of the Frame Header
  *           or an error code, which can be tested with ZSTD_isError() */
 static size_t ZSTD_frameHeaderSize_internal(const void* src, size_t srcSize, ZSTD_format_e format)
 {
     size_t const minInputSize = ZSTD_startingInputLength(format);
     if (srcSize < minInputSize) return ERROR(srcSize_wrong);
 
     {   BYTE const fhd = ((const BYTE*)src)[minInputSize-1];
         U32 const dictID= fhd & 3;
         U32 const singleSegment = (fhd >> 5) & 1;
         U32 const fcsId = fhd >> 6;
         return minInputSize + !singleSegment
              + ZSTD_did_fieldSize[dictID] + ZSTD_fcs_fieldSize[fcsId]
              + (singleSegment && !fcsId);
     }
 }
 
 /** ZSTD_frameHeaderSize() :
  *  srcSize must be >= ZSTD_frameHeaderSize_prefix.
  * @return : size of the Frame Header */
 size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize)
 {
     return ZSTD_frameHeaderSize_internal(src, srcSize, ZSTD_f_zstd1);
 }
 
 
 /** ZSTD_getFrameHeader_internal() :
  *  decode Frame Header, or require larger `srcSize`.
  *  note : only works for formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless
  * @return : 0, `zfhPtr` is correctly filled,
  *          >0, `srcSize` is too small, value is wanted `srcSize` amount,
  *           or an error code, which can be tested using ZSTD_isError() */
 static size_t ZSTD_getFrameHeader_internal(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize, ZSTD_format_e format)
 {
     const BYTE* ip = (const BYTE*)src;
     size_t const minInputSize = ZSTD_startingInputLength(format);
 
     if (srcSize < minInputSize) return minInputSize;
 
     if ( (format != ZSTD_f_zstd1_magicless)
       && (MEM_readLE32(src) != ZSTD_MAGICNUMBER) ) {
         if ((MEM_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
             /* skippable frame */
             if (srcSize < ZSTD_skippableHeaderSize)
                 return ZSTD_skippableHeaderSize; /* magic number + frame length */
             memset(zfhPtr, 0, sizeof(*zfhPtr));
             zfhPtr->frameContentSize = MEM_readLE32((const char *)src + ZSTD_frameIdSize);
             zfhPtr->frameType = ZSTD_skippableFrame;
             return 0;
         }
         return ERROR(prefix_unknown);
     }
 
     /* ensure there is enough `srcSize` to fully read/decode frame header */
     {   size_t const fhsize = ZSTD_frameHeaderSize_internal(src, srcSize, format);
         if (srcSize < fhsize) return fhsize;
         zfhPtr->headerSize = (U32)fhsize;
     }
 
     {   BYTE const fhdByte = ip[minInputSize-1];
         size_t pos = minInputSize;
         U32 const dictIDSizeCode = fhdByte&3;
         U32 const checksumFlag = (fhdByte>>2)&1;
         U32 const singleSegment = (fhdByte>>5)&1;
         U32 const fcsID = fhdByte>>6;
         U64 windowSize = 0;
         U32 dictID = 0;
         U64 frameContentSize = ZSTD_CONTENTSIZE_UNKNOWN;
         if ((fhdByte & 0x08) != 0)
             return ERROR(frameParameter_unsupported); /* reserved bits, must be zero */
 
         if (!singleSegment) {
             BYTE const wlByte = ip[pos++];
             U32 const windowLog = (wlByte >> 3) + ZSTD_WINDOWLOG_ABSOLUTEMIN;
             if (windowLog > ZSTD_WINDOWLOG_MAX)
                 return ERROR(frameParameter_windowTooLarge);
             windowSize = (1ULL << windowLog);
             windowSize += (windowSize >> 3) * (wlByte&7);
         }
         switch(dictIDSizeCode)
         {
             default: assert(0);  /* impossible */
             case 0 : break;
             case 1 : dictID = ip[pos]; pos++; break;
             case 2 : dictID = MEM_readLE16(ip+pos); pos+=2; break;
             case 3 : dictID = MEM_readLE32(ip+pos); pos+=4; break;
         }
         switch(fcsID)
         {
             default: assert(0);  /* impossible */
             case 0 : if (singleSegment) frameContentSize = ip[pos]; break;
             case 1 : frameContentSize = MEM_readLE16(ip+pos)+256; break;
             case 2 : frameContentSize = MEM_readLE32(ip+pos); break;
             case 3 : frameContentSize = MEM_readLE64(ip+pos); break;
         }
         if (singleSegment) windowSize = frameContentSize;
 
         zfhPtr->frameType = ZSTD_frame;
         zfhPtr->frameContentSize = frameContentSize;
         zfhPtr->windowSize = windowSize;
         zfhPtr->blockSizeMax = (unsigned) MIN(windowSize, ZSTD_BLOCKSIZE_MAX);
         zfhPtr->dictID = dictID;
         zfhPtr->checksumFlag = checksumFlag;
     }
     return 0;
 }
 
 /** ZSTD_getFrameHeader() :
  *  decode Frame Header, or require larger `srcSize`.
  *  note : this function does not consume input, it only reads it.
  * @return : 0, `zfhPtr` is correctly filled,
  *          >0, `srcSize` is too small, value is wanted `srcSize` amount,
  *           or an error code, which can be tested using ZSTD_isError() */
 size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize)
 {
     return ZSTD_getFrameHeader_internal(zfhPtr, src, srcSize, ZSTD_f_zstd1);
 }
 
 
 /** ZSTD_getFrameContentSize() :
  *  compatible with legacy mode
  * @return : decompressed size of the single frame pointed to be `src` if known, otherwise
  *         - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
  *         - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) */
 unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize)
 {
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
     if (ZSTD_isLegacy(src, srcSize)) {
         unsigned long long const ret = ZSTD_getDecompressedSize_legacy(src, srcSize);
         return ret == 0 ? ZSTD_CONTENTSIZE_UNKNOWN : ret;
     }
 #endif
     {   ZSTD_frameHeader zfh;
         if (ZSTD_getFrameHeader(&zfh, src, srcSize) != 0)
             return ZSTD_CONTENTSIZE_ERROR;
         if (zfh.frameType == ZSTD_skippableFrame) {
             return 0;
         } else {
             return zfh.frameContentSize;
     }   }
 }
 
 /** ZSTD_findDecompressedSize() :
  *  compatible with legacy mode
  *  `srcSize` must be the exact length of some number of ZSTD compressed and/or
  *      skippable frames
  *  @return : decompressed size of the frames contained */
 unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize)
 {
     unsigned long long totalDstSize = 0;
 
     while (srcSize >= ZSTD_frameHeaderSize_prefix) {
         U32 const magicNumber = MEM_readLE32(src);
 
         if ((magicNumber & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
             size_t skippableSize;
             if (srcSize < ZSTD_skippableHeaderSize)
                 return ERROR(srcSize_wrong);
             skippableSize = MEM_readLE32((const BYTE *)src + ZSTD_frameIdSize)
                           + ZSTD_skippableHeaderSize;
             if (srcSize < skippableSize) {
                 return ZSTD_CONTENTSIZE_ERROR;
             }
 
             src = (const BYTE *)src + skippableSize;
             srcSize -= skippableSize;
             continue;
         }
 
         {   unsigned long long const ret = ZSTD_getFrameContentSize(src, srcSize);
             if (ret >= ZSTD_CONTENTSIZE_ERROR) return ret;
 
             /* check for overflow */
             if (totalDstSize + ret < totalDstSize) return ZSTD_CONTENTSIZE_ERROR;
             totalDstSize += ret;
         }
         {   size_t const frameSrcSize = ZSTD_findFrameCompressedSize(src, srcSize);
             if (ZSTD_isError(frameSrcSize)) {
                 return ZSTD_CONTENTSIZE_ERROR;
             }
 
             src = (const BYTE *)src + frameSrcSize;
             srcSize -= frameSrcSize;
         }
     }  /* while (srcSize >= ZSTD_frameHeaderSize_prefix) */
 
     if (srcSize) return ZSTD_CONTENTSIZE_ERROR;
 
     return totalDstSize;
 }
 
 /** ZSTD_getDecompressedSize() :
 *   compatible with legacy mode
 *   @return : decompressed size if known, 0 otherwise
               note : 0 can mean any of the following :
                    - frame content is empty
                    - decompressed size field is not present in frame header
                    - frame header unknown / not supported
                    - frame header not complete (`srcSize` too small) */
 unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize)
 {
     unsigned long long const ret = ZSTD_getFrameContentSize(src, srcSize);
     ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_ERROR < ZSTD_CONTENTSIZE_UNKNOWN);
     return (ret >= ZSTD_CONTENTSIZE_ERROR) ? 0 : ret;
 }
 
 
 /** ZSTD_decodeFrameHeader() :
 *   `headerSize` must be the size provided by ZSTD_frameHeaderSize().
 *   @return : 0 if success, or an error code, which can be tested using ZSTD_isError() */
 static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx* dctx, const void* src, size_t headerSize)
 {
     size_t const result = ZSTD_getFrameHeader_internal(&(dctx->fParams), src, headerSize, dctx->format);
     if (ZSTD_isError(result)) return result;    /* invalid header */
     if (result>0) return ERROR(srcSize_wrong);  /* headerSize too small */
     if (dctx->fParams.dictID && (dctx->dictID != dctx->fParams.dictID))
         return ERROR(dictionary_wrong);
     if (dctx->fParams.checksumFlag) XXH64_reset(&dctx->xxhState, 0);
     return 0;
 }
 
 
 /*! ZSTD_getcBlockSize() :
 *   Provides the size of compressed block from block header `src` */
 size_t ZSTD_getcBlockSize(const void* src, size_t srcSize,
                           blockProperties_t* bpPtr)
 {
     if (srcSize < ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
     {   U32 const cBlockHeader = MEM_readLE24(src);
         U32 const cSize = cBlockHeader >> 3;
         bpPtr->lastBlock = cBlockHeader & 1;
         bpPtr->blockType = (blockType_e)((cBlockHeader >> 1) & 3);
         bpPtr->origSize = cSize;   /* only useful for RLE */
         if (bpPtr->blockType == bt_rle) return 1;
         if (bpPtr->blockType == bt_reserved) return ERROR(corruption_detected);
         return cSize;
     }
 }
 
 
 static size_t ZSTD_copyRawBlock(void* dst, size_t dstCapacity,
                           const void* src, size_t srcSize)
 {
     if (srcSize > dstCapacity) return ERROR(dstSize_tooSmall);
     memcpy(dst, src, srcSize);
     return srcSize;
 }
 
 
 static size_t ZSTD_setRleBlock(void* dst, size_t dstCapacity,
                          const void* src, size_t srcSize,
                                size_t regenSize)
 {
     if (srcSize != 1) return ERROR(srcSize_wrong);
     if (regenSize > dstCapacity) return ERROR(dstSize_tooSmall);
     memset(dst, *(const BYTE*)src, regenSize);
     return regenSize;
 }
 
 /*! ZSTD_decodeLiteralsBlock() :
  * @return : nb of bytes read from src (< srcSize )
  *  note : symbol not declared but exposed for fullbench */
 size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
                           const void* src, size_t srcSize)   /* note : srcSize < BLOCKSIZE */
 {
     if (srcSize < MIN_CBLOCK_SIZE) return ERROR(corruption_detected);
 
     {   const BYTE* const istart = (const BYTE*) src;
         symbolEncodingType_e const litEncType = (symbolEncodingType_e)(istart[0] & 3);
 
         switch(litEncType)
         {
         case set_repeat:
             if (dctx->litEntropy==0) return ERROR(dictionary_corrupted);
             /* fall-through */
         case set_compressed:
             if (srcSize < 5) return ERROR(corruption_detected);   /* srcSize >= MIN_CBLOCK_SIZE == 3; here we need up to 5 for case 3 */
             {   size_t lhSize, litSize, litCSize;
                 U32 singleStream=0;
                 U32 const lhlCode = (istart[0] >> 2) & 3;
                 U32 const lhc = MEM_readLE32(istart);
                 switch(lhlCode)
                 {
                 case 0: case 1: default:   /* note : default is impossible, since lhlCode into [0..3] */
                     /* 2 - 2 - 10 - 10 */
                     singleStream = !lhlCode;
                     lhSize = 3;
                     litSize  = (lhc >> 4) & 0x3FF;
                     litCSize = (lhc >> 14) & 0x3FF;
                     break;
                 case 2:
                     /* 2 - 2 - 14 - 14 */
                     lhSize = 4;
                     litSize  = (lhc >> 4) & 0x3FFF;
                     litCSize = lhc >> 18;
                     break;
                 case 3:
                     /* 2 - 2 - 18 - 18 */
                     lhSize = 5;
                     litSize  = (lhc >> 4) & 0x3FFFF;
                     litCSize = (lhc >> 22) + (istart[4] << 10);
                     break;
                 }
                 if (litSize > ZSTD_BLOCKSIZE_MAX) return ERROR(corruption_detected);
                 if (litCSize + lhSize > srcSize) return ERROR(corruption_detected);
 
                 if (HUF_isError((litEncType==set_repeat) ?
                                     ( singleStream ?
                                         HUF_decompress1X_usingDTable(dctx->litBuffer, litSize, istart+lhSize, litCSize, dctx->HUFptr) :
                                         HUF_decompress4X_usingDTable(dctx->litBuffer, litSize, istart+lhSize, litCSize, dctx->HUFptr) ) :
                                     ( singleStream ?
                                         HUF_decompress1X2_DCtx_wksp(dctx->entropy.hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize,
                                                                     dctx->entropy.workspace, sizeof(dctx->entropy.workspace)) :
                                         HUF_decompress4X_hufOnly_wksp(dctx->entropy.hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize,
                                                                       dctx->entropy.workspace, sizeof(dctx->entropy.workspace)))))
                     return ERROR(corruption_detected);
 
                 dctx->litPtr = dctx->litBuffer;
                 dctx->litSize = litSize;
                 dctx->litEntropy = 1;
                 if (litEncType==set_compressed) dctx->HUFptr = dctx->entropy.hufTable;
                 memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
                 return litCSize + lhSize;
             }
 
         case set_basic:
             {   size_t litSize, lhSize;
                 U32 const lhlCode = ((istart[0]) >> 2) & 3;
                 switch(lhlCode)
                 {
                 case 0: case 2: default:   /* note : default is impossible, since lhlCode into [0..3] */
                     lhSize = 1;
                     litSize = istart[0] >> 3;
                     break;
                 case 1:
                     lhSize = 2;
                     litSize = MEM_readLE16(istart) >> 4;
                     break;
                 case 3:
                     lhSize = 3;
                     litSize = MEM_readLE24(istart) >> 4;
                     break;
                 }
 
                 if (lhSize+litSize+WILDCOPY_OVERLENGTH > srcSize) {  /* risk reading beyond src buffer with wildcopy */
                     if (litSize+lhSize > srcSize) return ERROR(corruption_detected);
                     memcpy(dctx->litBuffer, istart+lhSize, litSize);
                     dctx->litPtr = dctx->litBuffer;
                     dctx->litSize = litSize;
                     memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
                     return lhSize+litSize;
                 }
                 /* direct reference into compressed stream */
                 dctx->litPtr = istart+lhSize;
                 dctx->litSize = litSize;
                 return lhSize+litSize;
             }
 
         case set_rle:
             {   U32 const lhlCode = ((istart[0]) >> 2) & 3;
                 size_t litSize, lhSize;
                 switch(lhlCode)
                 {
                 case 0: case 2: default:   /* note : default is impossible, since lhlCode into [0..3] */
                     lhSize = 1;
                     litSize = istart[0] >> 3;
                     break;
                 case 1:
                     lhSize = 2;
                     litSize = MEM_readLE16(istart) >> 4;
                     break;
                 case 3:
                     lhSize = 3;
                     litSize = MEM_readLE24(istart) >> 4;
                     if (srcSize<4) return ERROR(corruption_detected);   /* srcSize >= MIN_CBLOCK_SIZE == 3; here we need lhSize+1 = 4 */
                     break;
                 }
                 if (litSize > ZSTD_BLOCKSIZE_MAX) return ERROR(corruption_detected);
                 memset(dctx->litBuffer, istart[lhSize], litSize + WILDCOPY_OVERLENGTH);
                 dctx->litPtr = dctx->litBuffer;
                 dctx->litSize = litSize;
                 return lhSize+1;
             }
         default:
             return ERROR(corruption_detected);   /* impossible */
         }
     }
 }
 
 
 typedef union {
     FSE_decode_t realData;
     U32 alignedBy4;
 } FSE_decode_t4;
 
 /* Default FSE distribution table for Literal Lengths */
 static const FSE_decode_t4 LL_defaultDTable[(1< max) return ERROR(corruption_detected);
         FSE_buildDTable_rle(DTableSpace, *(const BYTE*)src);
         *DTablePtr = DTableSpace;
         return 1;
     case set_basic :
         *DTablePtr = (const FSE_DTable*)tmpPtr;
         return 0;
     case set_repeat:
         if (!flagRepeatTable) return ERROR(corruption_detected);
         return 0;
     default :   /* impossible */
     case set_compressed :
         {   U32 tableLog;
             S16 norm[MaxSeq+1];
             size_t const headerSize = FSE_readNCount(norm, &max, &tableLog, src, srcSize);
             if (FSE_isError(headerSize)) return ERROR(corruption_detected);
             if (tableLog > maxLog) return ERROR(corruption_detected);
             FSE_buildDTable(DTableSpace, norm, max, tableLog);
             *DTablePtr = DTableSpace;
             return headerSize;
     }   }
 }
 
 size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr,
                              const void* src, size_t srcSize)
 {
     const BYTE* const istart = (const BYTE* const)src;
     const BYTE* const iend = istart + srcSize;
     const BYTE* ip = istart;
     DEBUGLOG(5, "ZSTD_decodeSeqHeaders");
 
     /* check */
     if (srcSize < MIN_SEQUENCES_SIZE) return ERROR(srcSize_wrong);
 
     /* SeqHead */
     {   int nbSeq = *ip++;
         if (!nbSeq) { *nbSeqPtr=0; return 1; }
         if (nbSeq > 0x7F) {
             if (nbSeq == 0xFF) {
                 if (ip+2 > iend) return ERROR(srcSize_wrong);
                 nbSeq = MEM_readLE16(ip) + LONGNBSEQ, ip+=2;
             } else {
                 if (ip >= iend) return ERROR(srcSize_wrong);
                 nbSeq = ((nbSeq-0x80)<<8) + *ip++;
             }
         }
         *nbSeqPtr = nbSeq;
     }
 
     /* FSE table descriptors */
     if (ip+4 > iend) return ERROR(srcSize_wrong); /* minimum possible size */
     {   symbolEncodingType_e const LLtype = (symbolEncodingType_e)(*ip >> 6);
         symbolEncodingType_e const OFtype = (symbolEncodingType_e)((*ip >> 4) & 3);
         symbolEncodingType_e const MLtype = (symbolEncodingType_e)((*ip >> 2) & 3);
         ip++;
 
         /* Build DTables */
         {   size_t const llhSize = ZSTD_buildSeqTable(dctx->entropy.LLTable, &dctx->LLTptr,
                                                       LLtype, MaxLL, LLFSELog,
                                                       ip, iend-ip, LL_defaultDTable, dctx->fseEntropy);
             if (ZSTD_isError(llhSize)) return ERROR(corruption_detected);
             ip += llhSize;
         }
         {   size_t const ofhSize = ZSTD_buildSeqTable(dctx->entropy.OFTable, &dctx->OFTptr,
                                                       OFtype, MaxOff, OffFSELog,
                                                       ip, iend-ip, OF_defaultDTable, dctx->fseEntropy);
             if (ZSTD_isError(ofhSize)) return ERROR(corruption_detected);
             ip += ofhSize;
         }
         {   size_t const mlhSize = ZSTD_buildSeqTable(dctx->entropy.MLTable, &dctx->MLTptr,
                                                       MLtype, MaxML, MLFSELog,
                                                       ip, iend-ip, ML_defaultDTable, dctx->fseEntropy);
             if (ZSTD_isError(mlhSize)) return ERROR(corruption_detected);
             ip += mlhSize;
         }
     }
 
     return ip-istart;
 }
 
 
 typedef struct {
     size_t litLength;
     size_t matchLength;
     size_t offset;
     const BYTE* match;
 } seq_t;
 
 typedef struct {
     BIT_DStream_t DStream;
     FSE_DState_t stateLL;
     FSE_DState_t stateOffb;
     FSE_DState_t stateML;
     size_t prevOffset[ZSTD_REP_NUM];
-    const BYTE* base;
+    const BYTE* prefixStart;
+    const BYTE* dictEnd;
     size_t pos;
-    uPtrDiff gotoDict;
 } seqState_t;
 
 
 FORCE_NOINLINE
 size_t ZSTD_execSequenceLast7(BYTE* op,
                               BYTE* const oend, seq_t sequence,
                               const BYTE** litPtr, const BYTE* const litLimit,
                               const BYTE* const base, const BYTE* const vBase, const BYTE* const dictEnd)
 {
     BYTE* const oLitEnd = op + sequence.litLength;
     size_t const sequenceLength = sequence.litLength + sequence.matchLength;
     BYTE* const oMatchEnd = op + sequenceLength;   /* risk : address space overflow (32-bits) */
     BYTE* const oend_w = oend - WILDCOPY_OVERLENGTH;
     const BYTE* const iLitEnd = *litPtr + sequence.litLength;
     const BYTE* match = oLitEnd - sequence.offset;
 
     /* check */
     if (oMatchEnd>oend) return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
     if (iLitEnd > litLimit) return ERROR(corruption_detected);   /* over-read beyond lit buffer */
     if (oLitEnd <= oend_w) return ERROR(GENERIC);   /* Precondition */
 
     /* copy literals */
     if (op < oend_w) {
         ZSTD_wildcopy(op, *litPtr, oend_w - op);
         *litPtr += oend_w - op;
         op = oend_w;
     }
     while (op < oLitEnd) *op++ = *(*litPtr)++;
 
     /* copy Match */
     if (sequence.offset > (size_t)(oLitEnd - base)) {
         /* offset beyond prefix */
         if (sequence.offset > (size_t)(oLitEnd - vBase)) return ERROR(corruption_detected);
         match = dictEnd - (base-match);
         if (match + sequence.matchLength <= dictEnd) {
             memmove(oLitEnd, match, sequence.matchLength);
             return sequenceLength;
         }
         /* span extDict & currentPrefixSegment */
         {   size_t const length1 = dictEnd - match;
             memmove(oLitEnd, match, length1);
             op = oLitEnd + length1;
             sequence.matchLength -= length1;
             match = base;
     }   }
     while (op < oMatchEnd) *op++ = *match++;
     return sequenceLength;
 }
 
 
 typedef enum { ZSTD_lo_isRegularOffset, ZSTD_lo_isLongOffset=1 } ZSTD_longOffset_e;
 
 /* We need to add at most (ZSTD_WINDOWLOG_MAX_32 - 1) bits to read the maximum
  * offset bits. But we can only read at most (STREAM_ACCUMULATOR_MIN_32 - 1)
  * bits before reloading. This value is the maximum number of bytes we read
  * after reloading when we are decoding long offets.
  */
 #define LONG_OFFSETS_MAX_EXTRA_BITS_32                                         \
     (ZSTD_WINDOWLOG_MAX_32 > STREAM_ACCUMULATOR_MIN_32                         \
         ? ZSTD_WINDOWLOG_MAX_32 - STREAM_ACCUMULATOR_MIN_32                    \
         : 0)
 
 static seq_t ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets)
 {
     seq_t seq;
 
     U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
     U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
     U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb);   /* <= MaxOff, by table construction */
 
     U32 const llBits = LL_bits[llCode];
     U32 const mlBits = ML_bits[mlCode];
     U32 const ofBits = ofCode;
     U32 const totalBits = llBits+mlBits+ofBits;
 
     static const U32 LL_base[MaxLL+1] = {
                              0,    1,    2,     3,     4,     5,     6,      7,
                              8,    9,   10,    11,    12,    13,    14,     15,
                             16,   18,   20,    22,    24,    28,    32,     40,
                             48,   64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000,
                             0x2000, 0x4000, 0x8000, 0x10000 };
 
     static const U32 ML_base[MaxML+1] = {
                              3,  4,  5,    6,     7,     8,     9,    10,
                             11, 12, 13,   14,    15,    16,    17,    18,
                             19, 20, 21,   22,    23,    24,    25,    26,
                             27, 28, 29,   30,    31,    32,    33,    34,
                             35, 37, 39,   41,    43,    47,    51,    59,
                             67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803,
                             0x1003, 0x2003, 0x4003, 0x8003, 0x10003 };
 
     static const U32 OF_base[MaxOff+1] = {
                      0,        1,       1,       5,     0xD,     0x1D,     0x3D,     0x7D,
                      0xFD,   0x1FD,   0x3FD,   0x7FD,   0xFFD,   0x1FFD,   0x3FFD,   0x7FFD,
                      0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD,
                      0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD };
 
     /* sequence */
     {   size_t offset;
         if (!ofCode)
             offset = 0;
         else {
             ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1);
             ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 5);
             assert(ofBits <= MaxOff);
             if (MEM_32bits() && longOffsets) {
                 U32 const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN_32-1);
                 offset = OF_base[ofCode] + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
                 if (MEM_32bits() || extraBits) BIT_reloadDStream(&seqState->DStream);
                 if (extraBits) offset += BIT_readBitsFast(&seqState->DStream, extraBits);
             } else {
                 offset = OF_base[ofCode] + BIT_readBitsFast(&seqState->DStream, ofBits);   /* <=  (ZSTD_WINDOWLOG_MAX-1) bits */
                 if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream);
             }
         }
 
         if (ofCode <= 1) {
             offset += (llCode==0);
             if (offset) {
                 size_t temp = (offset==3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
                 temp += !temp;   /* 0 is not valid; input is corrupted; force offset to 1 */
                 if (offset != 1) seqState->prevOffset[2] = seqState->prevOffset[1];
                 seqState->prevOffset[1] = seqState->prevOffset[0];
                 seqState->prevOffset[0] = offset = temp;
             } else {
                 offset = seqState->prevOffset[0];
             }
         } else {
             seqState->prevOffset[2] = seqState->prevOffset[1];
             seqState->prevOffset[1] = seqState->prevOffset[0];
             seqState->prevOffset[0] = offset;
         }
         seq.offset = offset;
     }
 
     seq.matchLength = ML_base[mlCode]
                     + ((mlCode>31) ? BIT_readBitsFast(&seqState->DStream, mlBits) : 0);  /* <=  16 bits */
     if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32))
         BIT_reloadDStream(&seqState->DStream);
     if (MEM_64bits() && (totalBits >= STREAM_ACCUMULATOR_MIN_64-(LLFSELog+MLFSELog+OffFSELog)))
         BIT_reloadDStream(&seqState->DStream);
     /* Verify that there is enough bits to read the rest of the data in 64-bit mode. */
     ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64);
 
     seq.litLength = LL_base[llCode]
                   + ((llCode>15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0);    /* <=  16 bits */
     if (MEM_32bits())
         BIT_reloadDStream(&seqState->DStream);
 
     DEBUGLOG(6, "seq: litL=%u, matchL=%u, offset=%u",
                 (U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset);
 
     /* ANS state update */
     FSE_updateState(&seqState->stateLL, &seqState->DStream);    /* <=  9 bits */
     FSE_updateState(&seqState->stateML, &seqState->DStream);    /* <=  9 bits */
     if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream);    /* <= 18 bits */
     FSE_updateState(&seqState->stateOffb, &seqState->DStream);  /* <=  8 bits */
 
     return seq;
 }
 
 
 HINT_INLINE
 size_t ZSTD_execSequence(BYTE* op,
                          BYTE* const oend, seq_t sequence,
                          const BYTE** litPtr, const BYTE* const litLimit,
                          const BYTE* const base, const BYTE* const vBase, const BYTE* const dictEnd)
 {
     BYTE* const oLitEnd = op + sequence.litLength;
     size_t const sequenceLength = sequence.litLength + sequence.matchLength;
     BYTE* const oMatchEnd = op + sequenceLength;   /* risk : address space overflow (32-bits) */
     BYTE* const oend_w = oend - WILDCOPY_OVERLENGTH;
     const BYTE* const iLitEnd = *litPtr + sequence.litLength;
     const BYTE* match = oLitEnd - sequence.offset;
 
     /* check */
     if (oMatchEnd>oend) return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
     if (iLitEnd > litLimit) return ERROR(corruption_detected);   /* over-read beyond lit buffer */
     if (oLitEnd>oend_w) return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, base, vBase, dictEnd);
 
     /* copy Literals */
     ZSTD_copy8(op, *litPtr);
     if (sequence.litLength > 8)
         ZSTD_wildcopy(op+8, (*litPtr)+8, sequence.litLength - 8);   /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
     op = oLitEnd;
     *litPtr = iLitEnd;   /* update for next sequence */
 
     /* copy Match */
     if (sequence.offset > (size_t)(oLitEnd - base)) {
         /* offset beyond prefix -> go into extDict */
         if (sequence.offset > (size_t)(oLitEnd - vBase))
             return ERROR(corruption_detected);
         match = dictEnd + (match - base);
         if (match + sequence.matchLength <= dictEnd) {
             memmove(oLitEnd, match, sequence.matchLength);
             return sequenceLength;
         }
         /* span extDict & currentPrefixSegment */
         {   size_t const length1 = dictEnd - match;
             memmove(oLitEnd, match, length1);
             op = oLitEnd + length1;
             sequence.matchLength -= length1;
             match = base;
             if (op > oend_w || sequence.matchLength < MINMATCH) {
               U32 i;
               for (i = 0; i < sequence.matchLength; ++i) op[i] = match[i];
               return sequenceLength;
             }
     }   }
     /* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
 
     /* match within prefix */
     if (sequence.offset < 8) {
         /* close range match, overlap */
         static const U32 dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 };   /* added */
         static const int dec64table[] = { 8, 8, 8, 7, 8, 9,10,11 };   /* subtracted */
         int const sub2 = dec64table[sequence.offset];
         op[0] = match[0];
         op[1] = match[1];
         op[2] = match[2];
         op[3] = match[3];
         match += dec32table[sequence.offset];
         ZSTD_copy4(op+4, match);
         match -= sub2;
     } else {
         ZSTD_copy8(op, match);
     }
     op += 8; match += 8;
 
     if (oMatchEnd > oend-(16-MINMATCH)) {
         if (op < oend_w) {
             ZSTD_wildcopy(op, match, oend_w - op);
             match += oend_w - op;
             op = oend_w;
         }
         while (op < oMatchEnd) *op++ = *match++;
     } else {
         ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength-8);   /* works even if matchLength < 8 */
     }
     return sequenceLength;
 }
 
 
 static size_t ZSTD_decompressSequences(
                                ZSTD_DCtx* dctx,
                                void* dst, size_t maxDstSize,
                          const void* seqStart, size_t seqSize,
                          const ZSTD_longOffset_e isLongOffset)
 {
     const BYTE* ip = (const BYTE*)seqStart;
     const BYTE* const iend = ip + seqSize;
     BYTE* const ostart = (BYTE* const)dst;
     BYTE* const oend = ostart + maxDstSize;
     BYTE* op = ostart;
     const BYTE* litPtr = dctx->litPtr;
     const BYTE* const litEnd = litPtr + dctx->litSize;
     const BYTE* const base = (const BYTE*) (dctx->base);
     const BYTE* const vBase = (const BYTE*) (dctx->vBase);
     const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
     int nbSeq;
     DEBUGLOG(5, "ZSTD_decompressSequences");
 
     /* Build Decoding Tables */
     {   size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, seqSize);
         DEBUGLOG(5, "ZSTD_decodeSeqHeaders: size=%u, nbSeq=%i",
                     (U32)seqHSize, nbSeq);
         if (ZSTD_isError(seqHSize)) return seqHSize;
         ip += seqHSize;
     }
 
     /* Regen sequences */
     if (nbSeq) {
         seqState_t seqState;
         dctx->fseEntropy = 1;
         { U32 i; for (i=0; ientropy.rep[i]; }
         CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend-ip), corruption_detected);
         FSE_initDState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
         FSE_initDState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
         FSE_initDState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
 
         for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && nbSeq ; ) {
             nbSeq--;
             {   seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset);
                 size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litEnd, base, vBase, dictEnd);
                 DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize);
                 if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
                 op += oneSeqSize;
         }   }
 
         /* check if reached exact end */
         DEBUGLOG(5, "after decode loop, remaining nbSeq : %i", nbSeq);
         if (nbSeq) return ERROR(corruption_detected);
         /* save reps for next block */
         { U32 i; for (i=0; ientropy.rep[i] = (U32)(seqState.prevOffset[i]); }
     }
 
     /* last literal segment */
     {   size_t const lastLLSize = litEnd - litPtr;
         if (lastLLSize > (size_t)(oend-op)) return ERROR(dstSize_tooSmall);
         memcpy(op, litPtr, lastLLSize);
         op += lastLLSize;
     }
 
     return op-ostart;
 }
 
 
 HINT_INLINE
 seq_t ZSTD_decodeSequenceLong(seqState_t* seqState, ZSTD_longOffset_e const longOffsets)
 {
     seq_t seq;
 
     U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
     U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
     U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb);   /* <= MaxOff, by table construction */
 
     U32 const llBits = LL_bits[llCode];
     U32 const mlBits = ML_bits[mlCode];
     U32 const ofBits = ofCode;
     U32 const totalBits = llBits+mlBits+ofBits;
 
     static const U32 LL_base[MaxLL+1] = {
                              0,  1,    2,     3,     4,     5,     6,      7,
                              8,  9,   10,    11,    12,    13,    14,     15,
                             16, 18,   20,    22,    24,    28,    32,     40,
                             48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000,
                             0x2000, 0x4000, 0x8000, 0x10000 };
 
     static const U32 ML_base[MaxML+1] = {
                              3,  4,  5,    6,     7,     8,     9,    10,
                             11, 12, 13,   14,    15,    16,    17,    18,
                             19, 20, 21,   22,    23,    24,    25,    26,
                             27, 28, 29,   30,    31,    32,    33,    34,
                             35, 37, 39,   41,    43,    47,    51,    59,
                             67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803,
                             0x1003, 0x2003, 0x4003, 0x8003, 0x10003 };
 
     static const U32 OF_base[MaxOff+1] = {
                      0,        1,       1,       5,     0xD,     0x1D,     0x3D,     0x7D,
                      0xFD,   0x1FD,   0x3FD,   0x7FD,   0xFFD,   0x1FFD,   0x3FFD,   0x7FFD,
                      0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD,
                      0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD };
 
     /* sequence */
     {   size_t offset;
         if (!ofCode)
             offset = 0;
         else {
             ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1);
             ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 5);
             assert(ofBits <= MaxOff);
             if (MEM_32bits() && longOffsets) {
                 U32 const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN_32-1);
                 offset = OF_base[ofCode] + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
                 if (MEM_32bits() || extraBits) BIT_reloadDStream(&seqState->DStream);
                 if (extraBits) offset += BIT_readBitsFast(&seqState->DStream, extraBits);
             } else {
                 offset = OF_base[ofCode] + BIT_readBitsFast(&seqState->DStream, ofBits);   /* <=  (ZSTD_WINDOWLOG_MAX-1) bits */
                 if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream);
             }
         }
 
         if (ofCode <= 1) {
             offset += (llCode==0);
             if (offset) {
                 size_t temp = (offset==3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
                 temp += !temp;   /* 0 is not valid; input is corrupted; force offset to 1 */
                 if (offset != 1) seqState->prevOffset[2] = seqState->prevOffset[1];
                 seqState->prevOffset[1] = seqState->prevOffset[0];
                 seqState->prevOffset[0] = offset = temp;
             } else {
                 offset = seqState->prevOffset[0];
             }
         } else {
             seqState->prevOffset[2] = seqState->prevOffset[1];
             seqState->prevOffset[1] = seqState->prevOffset[0];
             seqState->prevOffset[0] = offset;
         }
         seq.offset = offset;
     }
 
     seq.matchLength = ML_base[mlCode] + ((mlCode>31) ? BIT_readBitsFast(&seqState->DStream, mlBits) : 0);  /* <=  16 bits */
     if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32))
         BIT_reloadDStream(&seqState->DStream);
     if (MEM_64bits() && (totalBits >= STREAM_ACCUMULATOR_MIN_64-(LLFSELog+MLFSELog+OffFSELog)))
         BIT_reloadDStream(&seqState->DStream);
     /* Verify that there is enough bits to read the rest of the data in 64-bit mode. */
     ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64);
 
     seq.litLength = LL_base[llCode] + ((llCode>15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0);    /* <=  16 bits */
     if (MEM_32bits())
         BIT_reloadDStream(&seqState->DStream);
 
     {   size_t const pos = seqState->pos + seq.litLength;
-        seq.match = seqState->base + pos - seq.offset;    /* single memory segment */
-        if (seq.offset > pos) seq.match += seqState->gotoDict;   /* separate memory segment */
+        const BYTE* const matchBase = (seq.offset > pos) ? seqState->dictEnd : seqState->prefixStart;
+        seq.match = matchBase + pos - seq.offset;  /* note : this operation can overflow when seq.offset is really too large, which can only happen when input is corrupted.
+                                                    * No consequence though : no memory access will occur, overly large offset will be detected in ZSTD_execSequenceLong() */
         seqState->pos = pos + seq.matchLength;
     }
 
     /* ANS state update */
     FSE_updateState(&seqState->stateLL, &seqState->DStream);    /* <=  9 bits */
     FSE_updateState(&seqState->stateML, &seqState->DStream);    /* <=  9 bits */
     if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream);    /* <= 18 bits */
     FSE_updateState(&seqState->stateOffb, &seqState->DStream);  /* <=  8 bits */
 
     return seq;
 }
 
 
 HINT_INLINE
 size_t ZSTD_execSequenceLong(BYTE* op,
                              BYTE* const oend, seq_t sequence,
                              const BYTE** litPtr, const BYTE* const litLimit,
-                             const BYTE* const base, const BYTE* const vBase, const BYTE* const dictEnd)
+                             const BYTE* const prefixStart, const BYTE* const dictStart, const BYTE* const dictEnd)
 {
     BYTE* const oLitEnd = op + sequence.litLength;
     size_t const sequenceLength = sequence.litLength + sequence.matchLength;
     BYTE* const oMatchEnd = op + sequenceLength;   /* risk : address space overflow (32-bits) */
     BYTE* const oend_w = oend - WILDCOPY_OVERLENGTH;
     const BYTE* const iLitEnd = *litPtr + sequence.litLength;
     const BYTE* match = sequence.match;
 
     /* check */
-    if (oMatchEnd>oend) return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
+    if (oMatchEnd > oend) return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
     if (iLitEnd > litLimit) return ERROR(corruption_detected);   /* over-read beyond lit buffer */
-    if (oLitEnd>oend_w) return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, base, vBase, dictEnd);
+    if (oLitEnd > oend_w) return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, prefixStart, dictStart, dictEnd);
 
     /* copy Literals */
-    ZSTD_copy8(op, *litPtr);
+    ZSTD_copy8(op, *litPtr);  /* note : op <= oLitEnd <= oend_w == oend - 8 */
     if (sequence.litLength > 8)
         ZSTD_wildcopy(op+8, (*litPtr)+8, sequence.litLength - 8);   /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
     op = oLitEnd;
     *litPtr = iLitEnd;   /* update for next sequence */
 
     /* copy Match */
-    if (sequence.offset > (size_t)(oLitEnd - base)) {
+    if (sequence.offset > (size_t)(oLitEnd - prefixStart)) {
         /* offset beyond prefix */
-        if (sequence.offset > (size_t)(oLitEnd - vBase)) return ERROR(corruption_detected);
+        if (sequence.offset > (size_t)(oLitEnd - dictStart)) return ERROR(corruption_detected);
         if (match + sequence.matchLength <= dictEnd) {
             memmove(oLitEnd, match, sequence.matchLength);
             return sequenceLength;
         }
         /* span extDict & currentPrefixSegment */
         {   size_t const length1 = dictEnd - match;
             memmove(oLitEnd, match, length1);
             op = oLitEnd + length1;
             sequence.matchLength -= length1;
-            match = base;
+            match = prefixStart;
             if (op > oend_w || sequence.matchLength < MINMATCH) {
               U32 i;
               for (i = 0; i < sequence.matchLength; ++i) op[i] = match[i];
               return sequenceLength;
             }
     }   }
     assert(op <= oend_w);
     assert(sequence.matchLength >= MINMATCH);
 
     /* match within prefix */
     if (sequence.offset < 8) {
         /* close range match, overlap */
         static const U32 dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 };   /* added */
         static const int dec64table[] = { 8, 8, 8, 7, 8, 9,10,11 };   /* subtracted */
         int const sub2 = dec64table[sequence.offset];
         op[0] = match[0];
         op[1] = match[1];
         op[2] = match[2];
         op[3] = match[3];
         match += dec32table[sequence.offset];
         ZSTD_copy4(op+4, match);
         match -= sub2;
     } else {
         ZSTD_copy8(op, match);
     }
     op += 8; match += 8;
 
     if (oMatchEnd > oend-(16-MINMATCH)) {
         if (op < oend_w) {
             ZSTD_wildcopy(op, match, oend_w - op);
             match += oend_w - op;
             op = oend_w;
         }
         while (op < oMatchEnd) *op++ = *match++;
     } else {
         ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength-8);   /* works even if matchLength < 8 */
     }
     return sequenceLength;
 }
 
 static size_t ZSTD_decompressSequencesLong(
                                ZSTD_DCtx* dctx,
                                void* dst, size_t maxDstSize,
                          const void* seqStart, size_t seqSize,
                          const ZSTD_longOffset_e isLongOffset)
 {
     const BYTE* ip = (const BYTE*)seqStart;
     const BYTE* const iend = ip + seqSize;
     BYTE* const ostart = (BYTE* const)dst;
     BYTE* const oend = ostart + maxDstSize;
     BYTE* op = ostart;
     const BYTE* litPtr = dctx->litPtr;
     const BYTE* const litEnd = litPtr + dctx->litSize;
-    const BYTE* const base = (const BYTE*) (dctx->base);
-    const BYTE* const vBase = (const BYTE*) (dctx->vBase);
+    const BYTE* const prefixStart = (const BYTE*) (dctx->base);
+    const BYTE* const dictStart = (const BYTE*) (dctx->vBase);
     const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
     int nbSeq;
 
     /* Build Decoding Tables */
     {   size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, seqSize);
         if (ZSTD_isError(seqHSize)) return seqHSize;
         ip += seqHSize;
     }
 
     /* Regen sequences */
     if (nbSeq) {
 #define STORED_SEQS 4
 #define STOSEQ_MASK (STORED_SEQS-1)
 #define ADVANCED_SEQS 4
         seq_t sequences[STORED_SEQS];
         int const seqAdvance = MIN(nbSeq, ADVANCED_SEQS);
         seqState_t seqState;
         int seqNb;
         dctx->fseEntropy = 1;
         { U32 i; for (i=0; ientropy.rep[i]; }
-        seqState.base = base;
-        seqState.pos = (size_t)(op-base);
-        seqState.gotoDict = (uPtrDiff)dictEnd - (uPtrDiff)base; /* cast to avoid undefined behaviour */
+        seqState.prefixStart = prefixStart;
+        seqState.pos = (size_t)(op-prefixStart);
+        seqState.dictEnd = dictEnd;
         CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend-ip), corruption_detected);
         FSE_initDState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
         FSE_initDState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
         FSE_initDState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
 
         /* prepare in advance */
         for (seqNb=0; (BIT_reloadDStream(&seqState.DStream) <= BIT_DStream_completed) && seqNbentropy.rep[i] = (U32)(seqState.prevOffset[i]); }
     }
 
     /* last literal segment */
     {   size_t const lastLLSize = litEnd - litPtr;
         if (lastLLSize > (size_t)(oend-op)) return ERROR(dstSize_tooSmall);
         memcpy(op, litPtr, lastLLSize);
         op += lastLLSize;
     }
 
     return op-ostart;
 }
 
 
 static size_t ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx,
                             void* dst, size_t dstCapacity,
                       const void* src, size_t srcSize, const int frame)
 {   /* blockType == blockCompressed */
     const BYTE* ip = (const BYTE*)src;
     /* isLongOffset must be true if there are long offsets.
      * Offsets are long if they are larger than 2^STREAM_ACCUMULATOR_MIN.
      * We don't expect that to be the case in 64-bit mode.
      * If we are in block mode we don't know the window size, so we have to be
      * conservative.
      */
     ZSTD_longOffset_e const isLongOffset = (ZSTD_longOffset_e)(MEM_32bits() && (!frame || dctx->fParams.windowSize > (1ULL << STREAM_ACCUMULATOR_MIN)));
     /* windowSize could be any value at this point, since it is only validated
      * in the streaming API.
      */
     DEBUGLOG(5, "ZSTD_decompressBlock_internal (size : %u)", (U32)srcSize);
 
     if (srcSize >= ZSTD_BLOCKSIZE_MAX) return ERROR(srcSize_wrong);
 
     /* Decode literals section */
     {   size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize);
         DEBUGLOG(5, "ZSTD_decodeLiteralsBlock : %u", (U32)litCSize);
         if (ZSTD_isError(litCSize)) return litCSize;
         ip += litCSize;
         srcSize -= litCSize;
     }
     if (frame && dctx->fParams.windowSize > (1<<23))
         return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize, isLongOffset);
     return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize, isLongOffset);
 }
 
 
 static void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst)
 {
     if (dst != dctx->previousDstEnd) {   /* not contiguous */
         dctx->dictEnd = dctx->previousDstEnd;
         dctx->vBase = (const char*)dst - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->base));
         dctx->base = dst;
         dctx->previousDstEnd = dst;
     }
 }
 
 size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx,
                             void* dst, size_t dstCapacity,
                       const void* src, size_t srcSize)
 {
     size_t dSize;
     ZSTD_checkContinuity(dctx, dst);
     dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, /* frame */ 0);
     dctx->previousDstEnd = (char*)dst + dSize;
     return dSize;
 }
 
 
 /** ZSTD_insertBlock() :
     insert `src` block into `dctx` history. Useful to track uncompressed blocks. */
 ZSTDLIB_API size_t ZSTD_insertBlock(ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize)
 {
     ZSTD_checkContinuity(dctx, blockStart);
     dctx->previousDstEnd = (const char*)blockStart + blockSize;
     return blockSize;
 }
 
 
 static size_t ZSTD_generateNxBytes(void* dst, size_t dstCapacity, BYTE byte, size_t length)
 {
     if (length > dstCapacity) return ERROR(dstSize_tooSmall);
     memset(dst, byte, length);
     return length;
 }
 
 /** ZSTD_findFrameCompressedSize() :
  *  compatible with legacy mode
  *  `src` must point to the start of a ZSTD frame, ZSTD legacy frame, or skippable frame
  *  `srcSize` must be at least as large as the frame contained
  *  @return : the compressed size of the frame starting at `src` */
 size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize)
 {
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
     if (ZSTD_isLegacy(src, srcSize))
         return ZSTD_findFrameCompressedSizeLegacy(src, srcSize);
 #endif
     if ( (srcSize >= ZSTD_skippableHeaderSize)
       && (MEM_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START ) {
         return ZSTD_skippableHeaderSize + MEM_readLE32((const BYTE*)src + ZSTD_frameIdSize);
     } else {
         const BYTE* ip = (const BYTE*)src;
         const BYTE* const ipstart = ip;
         size_t remainingSize = srcSize;
         ZSTD_frameHeader zfh;
 
         /* Extract Frame Header */
         {   size_t const ret = ZSTD_getFrameHeader(&zfh, src, srcSize);
             if (ZSTD_isError(ret)) return ret;
             if (ret > 0) return ERROR(srcSize_wrong);
         }
 
         ip += zfh.headerSize;
         remainingSize -= zfh.headerSize;
 
         /* Loop on each block */
         while (1) {
             blockProperties_t blockProperties;
             size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
             if (ZSTD_isError(cBlockSize)) return cBlockSize;
 
             if (ZSTD_blockHeaderSize + cBlockSize > remainingSize)
                 return ERROR(srcSize_wrong);
 
             ip += ZSTD_blockHeaderSize + cBlockSize;
             remainingSize -= ZSTD_blockHeaderSize + cBlockSize;
 
             if (blockProperties.lastBlock) break;
         }
 
         if (zfh.checksumFlag) {   /* Final frame content checksum */
             if (remainingSize < 4) return ERROR(srcSize_wrong);
             ip += 4;
             remainingSize -= 4;
         }
 
         return ip - ipstart;
     }
 }
 
 /*! ZSTD_decompressFrame() :
 *   @dctx must be properly initialized */
 static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
                                    void* dst, size_t dstCapacity,
                              const void** srcPtr, size_t *srcSizePtr)
 {
     const BYTE* ip = (const BYTE*)(*srcPtr);
     BYTE* const ostart = (BYTE* const)dst;
     BYTE* const oend = ostart + dstCapacity;
     BYTE* op = ostart;
     size_t remainingSize = *srcSizePtr;
 
     /* check */
     if (remainingSize < ZSTD_frameHeaderSize_min+ZSTD_blockHeaderSize)
         return ERROR(srcSize_wrong);
 
     /* Frame Header */
     {   size_t const frameHeaderSize = ZSTD_frameHeaderSize(ip, ZSTD_frameHeaderSize_prefix);
         if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize;
         if (remainingSize < frameHeaderSize+ZSTD_blockHeaderSize)
             return ERROR(srcSize_wrong);
         CHECK_F( ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize) );
         ip += frameHeaderSize; remainingSize -= frameHeaderSize;
     }
 
     /* Loop on each block */
     while (1) {
         size_t decodedSize;
         blockProperties_t blockProperties;
         size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
         if (ZSTD_isError(cBlockSize)) return cBlockSize;
 
         ip += ZSTD_blockHeaderSize;
         remainingSize -= ZSTD_blockHeaderSize;
         if (cBlockSize > remainingSize) return ERROR(srcSize_wrong);
 
         switch(blockProperties.blockType)
         {
         case bt_compressed:
             decodedSize = ZSTD_decompressBlock_internal(dctx, op, oend-op, ip, cBlockSize, /* frame */ 1);
             break;
         case bt_raw :
             decodedSize = ZSTD_copyRawBlock(op, oend-op, ip, cBlockSize);
             break;
         case bt_rle :
             decodedSize = ZSTD_generateNxBytes(op, oend-op, *ip, blockProperties.origSize);
             break;
         case bt_reserved :
         default:
             return ERROR(corruption_detected);
         }
 
         if (ZSTD_isError(decodedSize)) return decodedSize;
         if (dctx->fParams.checksumFlag)
             XXH64_update(&dctx->xxhState, op, decodedSize);
         op += decodedSize;
         ip += cBlockSize;
         remainingSize -= cBlockSize;
         if (blockProperties.lastBlock) break;
     }
 
     if (dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN) {
         if ((U64)(op-ostart) != dctx->fParams.frameContentSize) {
             return ERROR(corruption_detected);
     }   }
     if (dctx->fParams.checksumFlag) { /* Frame content checksum verification */
         U32 const checkCalc = (U32)XXH64_digest(&dctx->xxhState);
         U32 checkRead;
         if (remainingSize<4) return ERROR(checksum_wrong);
         checkRead = MEM_readLE32(ip);
         if (checkRead != checkCalc) return ERROR(checksum_wrong);
         ip += 4;
         remainingSize -= 4;
     }
 
     /* Allow caller to get size read */
     *srcPtr = ip;
     *srcSizePtr = remainingSize;
     return op-ostart;
 }
 
 static const void* ZSTD_DDictDictContent(const ZSTD_DDict* ddict);
 static size_t ZSTD_DDictDictSize(const ZSTD_DDict* ddict);
 
 static size_t ZSTD_decompressMultiFrame(ZSTD_DCtx* dctx,
                                         void* dst, size_t dstCapacity,
                                   const void* src, size_t srcSize,
                                   const void* dict, size_t dictSize,
                                   const ZSTD_DDict* ddict)
 {
     void* const dststart = dst;
     assert(dict==NULL || ddict==NULL);  /* either dict or ddict set, not both */
 
     if (ddict) {
         dict = ZSTD_DDictDictContent(ddict);
         dictSize = ZSTD_DDictDictSize(ddict);
     }
 
     while (srcSize >= ZSTD_frameHeaderSize_prefix) {
         U32 magicNumber;
 
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
         if (ZSTD_isLegacy(src, srcSize)) {
             size_t decodedSize;
             size_t const frameSize = ZSTD_findFrameCompressedSizeLegacy(src, srcSize);
             if (ZSTD_isError(frameSize)) return frameSize;
             /* legacy support is not compatible with static dctx */
             if (dctx->staticSize) return ERROR(memory_allocation);
 
             decodedSize = ZSTD_decompressLegacy(dst, dstCapacity, src, frameSize, dict, dictSize);
 
             dst = (BYTE*)dst + decodedSize;
             dstCapacity -= decodedSize;
 
             src = (const BYTE*)src + frameSize;
             srcSize -= frameSize;
 
             continue;
         }
 #endif
 
         magicNumber = MEM_readLE32(src);
         DEBUGLOG(4, "reading magic number %08X (expecting %08X)",
                     (U32)magicNumber, (U32)ZSTD_MAGICNUMBER);
         if (magicNumber != ZSTD_MAGICNUMBER) {
             if ((magicNumber & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
                 size_t skippableSize;
                 if (srcSize < ZSTD_skippableHeaderSize)
                     return ERROR(srcSize_wrong);
                 skippableSize = MEM_readLE32((const BYTE*)src + ZSTD_frameIdSize)
                               + ZSTD_skippableHeaderSize;
                 if (srcSize < skippableSize) return ERROR(srcSize_wrong);
 
                 src = (const BYTE *)src + skippableSize;
                 srcSize -= skippableSize;
                 continue;
             }
             return ERROR(prefix_unknown);
         }
 
         if (ddict) {
             /* we were called from ZSTD_decompress_usingDDict */
             CHECK_F(ZSTD_decompressBegin_usingDDict(dctx, ddict));
         } else {
             /* this will initialize correctly with no dict if dict == NULL, so
              * use this in all cases but ddict */
             CHECK_F(ZSTD_decompressBegin_usingDict(dctx, dict, dictSize));
         }
         ZSTD_checkContinuity(dctx, dst);
 
         {   const size_t res = ZSTD_decompressFrame(dctx, dst, dstCapacity,
                                                     &src, &srcSize);
             if (ZSTD_isError(res)) return res;
             /* no need to bound check, ZSTD_decompressFrame already has */
             dst = (BYTE*)dst + res;
             dstCapacity -= res;
         }
     }  /* while (srcSize >= ZSTD_frameHeaderSize_prefix) */
 
     if (srcSize) return ERROR(srcSize_wrong); /* input not entirely consumed */
 
     return (BYTE*)dst - (BYTE*)dststart;
 }
 
 size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
                                  void* dst, size_t dstCapacity,
                            const void* src, size_t srcSize,
                            const void* dict, size_t dictSize)
 {
     return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, dict, dictSize, NULL);
 }
 
 
 size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
 {
     return ZSTD_decompress_usingDict(dctx, dst, dstCapacity, src, srcSize, NULL, 0);
 }
 
 
 size_t ZSTD_decompress(void* dst, size_t dstCapacity, const void* src, size_t srcSize)
 {
 #if defined(ZSTD_HEAPMODE) && (ZSTD_HEAPMODE>=1)
     size_t regenSize;
     ZSTD_DCtx* const dctx = ZSTD_createDCtx();
     if (dctx==NULL) return ERROR(memory_allocation);
     regenSize = ZSTD_decompressDCtx(dctx, dst, dstCapacity, src, srcSize);
     ZSTD_freeDCtx(dctx);
     return regenSize;
 #else   /* stack mode */
     ZSTD_DCtx dctx;
     return ZSTD_decompressDCtx(&dctx, dst, dstCapacity, src, srcSize);
 #endif
 }
 
 
 /*-**************************************
 *   Advanced Streaming Decompression API
 *   Bufferless and synchronous
 ****************************************/
 size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx) { return dctx->expected; }
 
 ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx) {
     switch(dctx->stage)
     {
     default:   /* should not happen */
         assert(0);
     case ZSTDds_getFrameHeaderSize:
     case ZSTDds_decodeFrameHeader:
         return ZSTDnit_frameHeader;
     case ZSTDds_decodeBlockHeader:
         return ZSTDnit_blockHeader;
     case ZSTDds_decompressBlock:
         return ZSTDnit_block;
     case ZSTDds_decompressLastBlock:
         return ZSTDnit_lastBlock;
     case ZSTDds_checkChecksum:
         return ZSTDnit_checksum;
     case ZSTDds_decodeSkippableHeader:
     case ZSTDds_skipFrame:
         return ZSTDnit_skippableFrame;
     }
 }
 
 static int ZSTD_isSkipFrame(ZSTD_DCtx* dctx) { return dctx->stage == ZSTDds_skipFrame; }
 
 /** ZSTD_decompressContinue() :
  *  srcSize : must be the exact nb of bytes expected (see ZSTD_nextSrcSizeToDecompress())
  *  @return : nb of bytes generated into `dst` (necessarily <= `dstCapacity)
  *            or an error code, which can be tested using ZSTD_isError() */
 size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
 {
     DEBUGLOG(5, "ZSTD_decompressContinue");
     /* Sanity check */
     if (srcSize != dctx->expected) return ERROR(srcSize_wrong);  /* not allowed */
     if (dstCapacity) ZSTD_checkContinuity(dctx, dst);
 
     switch (dctx->stage)
     {
     case ZSTDds_getFrameHeaderSize :
         assert(src != NULL);
         if (dctx->format == ZSTD_f_zstd1) {  /* allows header */
             assert(srcSize >= ZSTD_frameIdSize);  /* to read skippable magic number */
             if ((MEM_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {        /* skippable frame */
                 memcpy(dctx->headerBuffer, src, srcSize);
                 dctx->expected = ZSTD_skippableHeaderSize - srcSize;  /* remaining to load to get full skippable frame header */
                 dctx->stage = ZSTDds_decodeSkippableHeader;
                 return 0;
         }   }
         dctx->headerSize = ZSTD_frameHeaderSize_internal(src, srcSize, dctx->format);
         if (ZSTD_isError(dctx->headerSize)) return dctx->headerSize;
         memcpy(dctx->headerBuffer, src, srcSize);
         dctx->expected = dctx->headerSize - srcSize;
         dctx->stage = ZSTDds_decodeFrameHeader;
         return 0;
 
     case ZSTDds_decodeFrameHeader:
         assert(src != NULL);
         memcpy(dctx->headerBuffer + (dctx->headerSize - srcSize), src, srcSize);
         CHECK_F(ZSTD_decodeFrameHeader(dctx, dctx->headerBuffer, dctx->headerSize));
         dctx->expected = ZSTD_blockHeaderSize;
         dctx->stage = ZSTDds_decodeBlockHeader;
         return 0;
 
     case ZSTDds_decodeBlockHeader:
         {   blockProperties_t bp;
             size_t const cBlockSize = ZSTD_getcBlockSize(src, ZSTD_blockHeaderSize, &bp);
             if (ZSTD_isError(cBlockSize)) return cBlockSize;
             dctx->expected = cBlockSize;
             dctx->bType = bp.blockType;
             dctx->rleSize = bp.origSize;
             if (cBlockSize) {
                 dctx->stage = bp.lastBlock ? ZSTDds_decompressLastBlock : ZSTDds_decompressBlock;
                 return 0;
             }
             /* empty block */
             if (bp.lastBlock) {
                 if (dctx->fParams.checksumFlag) {
                     dctx->expected = 4;
                     dctx->stage = ZSTDds_checkChecksum;
                 } else {
                     dctx->expected = 0; /* end of frame */
                     dctx->stage = ZSTDds_getFrameHeaderSize;
                 }
             } else {
                 dctx->expected = ZSTD_blockHeaderSize;  /* jump to next header */
                 dctx->stage = ZSTDds_decodeBlockHeader;
             }
             return 0;
         }
 
     case ZSTDds_decompressLastBlock:
     case ZSTDds_decompressBlock:
         DEBUGLOG(5, "case ZSTDds_decompressBlock");
         {   size_t rSize;
             switch(dctx->bType)
             {
             case bt_compressed:
                 DEBUGLOG(5, "case bt_compressed");
                 rSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, /* frame */ 1);
                 break;
             case bt_raw :
                 rSize = ZSTD_copyRawBlock(dst, dstCapacity, src, srcSize);
                 break;
             case bt_rle :
                 rSize = ZSTD_setRleBlock(dst, dstCapacity, src, srcSize, dctx->rleSize);
                 break;
             case bt_reserved :   /* should never happen */
             default:
                 return ERROR(corruption_detected);
             }
             if (ZSTD_isError(rSize)) return rSize;
             DEBUGLOG(5, "decoded size from block : %u", (U32)rSize);
             dctx->decodedSize += rSize;
             if (dctx->fParams.checksumFlag) XXH64_update(&dctx->xxhState, dst, rSize);
 
             if (dctx->stage == ZSTDds_decompressLastBlock) {   /* end of frame */
                 DEBUGLOG(4, "decoded size from frame : %u", (U32)dctx->decodedSize);
                 if (dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN) {
                     if (dctx->decodedSize != dctx->fParams.frameContentSize) {
                         return ERROR(corruption_detected);
                 }   }
                 if (dctx->fParams.checksumFlag) {  /* another round for frame checksum */
                     dctx->expected = 4;
                     dctx->stage = ZSTDds_checkChecksum;
                 } else {
                     dctx->expected = 0;   /* ends here */
                     dctx->stage = ZSTDds_getFrameHeaderSize;
                 }
             } else {
                 dctx->stage = ZSTDds_decodeBlockHeader;
                 dctx->expected = ZSTD_blockHeaderSize;
                 dctx->previousDstEnd = (char*)dst + rSize;
             }
             return rSize;
         }
 
     case ZSTDds_checkChecksum:
         assert(srcSize == 4);  /* guaranteed by dctx->expected */
         {   U32 const h32 = (U32)XXH64_digest(&dctx->xxhState);
             U32 const check32 = MEM_readLE32(src);
             DEBUGLOG(4, "checksum : calculated %08X :: %08X read", h32, check32);
             if (check32 != h32) return ERROR(checksum_wrong);
             dctx->expected = 0;
             dctx->stage = ZSTDds_getFrameHeaderSize;
             return 0;
         }
 
     case ZSTDds_decodeSkippableHeader:
         assert(src != NULL);
         assert(srcSize <= ZSTD_skippableHeaderSize);
         memcpy(dctx->headerBuffer + (ZSTD_skippableHeaderSize - srcSize), src, srcSize);   /* complete skippable header */
         dctx->expected = MEM_readLE32(dctx->headerBuffer + ZSTD_frameIdSize);   /* note : dctx->expected can grow seriously large, beyond local buffer size */
         dctx->stage = ZSTDds_skipFrame;
         return 0;
 
     case ZSTDds_skipFrame:
         dctx->expected = 0;
         dctx->stage = ZSTDds_getFrameHeaderSize;
         return 0;
 
     default:
         return ERROR(GENERIC);   /* impossible */
     }
 }
 
 
 static size_t ZSTD_refDictContent(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
 {
     dctx->dictEnd = dctx->previousDstEnd;
     dctx->vBase = (const char*)dict - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->base));
     dctx->base = dict;
     dctx->previousDstEnd = (const char*)dict + dictSize;
     return 0;
 }
 
 /* ZSTD_loadEntropy() :
  * dict : must point at beginning of a valid zstd dictionary
  * @return : size of entropy tables read */
 static size_t ZSTD_loadEntropy(ZSTD_entropyDTables_t* entropy, const void* const dict, size_t const dictSize)
 {
     const BYTE* dictPtr = (const BYTE*)dict;
     const BYTE* const dictEnd = dictPtr + dictSize;
 
     if (dictSize <= 8) return ERROR(dictionary_corrupted);
     dictPtr += 8;   /* skip header = magic + dictID */
 
 
     {   size_t const hSize = HUF_readDTableX4_wksp(
             entropy->hufTable, dictPtr, dictEnd - dictPtr,
             entropy->workspace, sizeof(entropy->workspace));
         if (HUF_isError(hSize)) return ERROR(dictionary_corrupted);
         dictPtr += hSize;
     }
 
     {   short offcodeNCount[MaxOff+1];
         U32 offcodeMaxValue = MaxOff, offcodeLog;
         size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, dictEnd-dictPtr);
         if (FSE_isError(offcodeHeaderSize)) return ERROR(dictionary_corrupted);
         if (offcodeLog > OffFSELog) return ERROR(dictionary_corrupted);
         CHECK_E(FSE_buildDTable(entropy->OFTable, offcodeNCount, offcodeMaxValue, offcodeLog), dictionary_corrupted);
         dictPtr += offcodeHeaderSize;
     }
 
     {   short matchlengthNCount[MaxML+1];
         unsigned matchlengthMaxValue = MaxML, matchlengthLog;
         size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd-dictPtr);
         if (FSE_isError(matchlengthHeaderSize)) return ERROR(dictionary_corrupted);
         if (matchlengthLog > MLFSELog) return ERROR(dictionary_corrupted);
         CHECK_E(FSE_buildDTable(entropy->MLTable, matchlengthNCount, matchlengthMaxValue, matchlengthLog), dictionary_corrupted);
         dictPtr += matchlengthHeaderSize;
     }
 
     {   short litlengthNCount[MaxLL+1];
         unsigned litlengthMaxValue = MaxLL, litlengthLog;
         size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd-dictPtr);
         if (FSE_isError(litlengthHeaderSize)) return ERROR(dictionary_corrupted);
         if (litlengthLog > LLFSELog) return ERROR(dictionary_corrupted);
         CHECK_E(FSE_buildDTable(entropy->LLTable, litlengthNCount, litlengthMaxValue, litlengthLog), dictionary_corrupted);
         dictPtr += litlengthHeaderSize;
     }
 
     if (dictPtr+12 > dictEnd) return ERROR(dictionary_corrupted);
     {   int i;
         size_t const dictContentSize = (size_t)(dictEnd - (dictPtr+12));
         for (i=0; i<3; i++) {
             U32 const rep = MEM_readLE32(dictPtr); dictPtr += 4;
             if (rep==0 || rep >= dictContentSize) return ERROR(dictionary_corrupted);
             entropy->rep[i] = rep;
     }   }
 
     return dictPtr - (const BYTE*)dict;
 }
 
 static size_t ZSTD_decompress_insertDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
 {
     if (dictSize < 8) return ZSTD_refDictContent(dctx, dict, dictSize);
     {   U32 const magic = MEM_readLE32(dict);
         if (magic != ZSTD_MAGIC_DICTIONARY) {
             return ZSTD_refDictContent(dctx, dict, dictSize);   /* pure content mode */
     }   }
     dctx->dictID = MEM_readLE32((const char*)dict + ZSTD_frameIdSize);
 
     /* load entropy tables */
     {   size_t const eSize = ZSTD_loadEntropy(&dctx->entropy, dict, dictSize);
         if (ZSTD_isError(eSize)) return ERROR(dictionary_corrupted);
         dict = (const char*)dict + eSize;
         dictSize -= eSize;
     }
     dctx->litEntropy = dctx->fseEntropy = 1;
 
     /* reference dictionary content */
     return ZSTD_refDictContent(dctx, dict, dictSize);
 }
 
 /* Note : this function cannot fail */
 size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx)
 {
     assert(dctx != NULL);
     dctx->expected = ZSTD_startingInputLength(dctx->format);  /* dctx->format must be properly set */
     dctx->stage = ZSTDds_getFrameHeaderSize;
     dctx->decodedSize = 0;
     dctx->previousDstEnd = NULL;
     dctx->base = NULL;
     dctx->vBase = NULL;
     dctx->dictEnd = NULL;
     dctx->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001);  /* cover both little and big endian */
     dctx->litEntropy = dctx->fseEntropy = 0;
     dctx->dictID = 0;
     ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.rep) == sizeof(repStartValue));
     memcpy(dctx->entropy.rep, repStartValue, sizeof(repStartValue));  /* initial repcodes */
     dctx->LLTptr = dctx->entropy.LLTable;
     dctx->MLTptr = dctx->entropy.MLTable;
     dctx->OFTptr = dctx->entropy.OFTable;
     dctx->HUFptr = dctx->entropy.hufTable;
     return 0;
 }
 
 size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
 {
     CHECK_F( ZSTD_decompressBegin(dctx) );
     if (dict && dictSize)
         CHECK_E(ZSTD_decompress_insertDictionary(dctx, dict, dictSize), dictionary_corrupted);
     return 0;
 }
 
 
 /* ======   ZSTD_DDict   ====== */
 
 struct ZSTD_DDict_s {
     void* dictBuffer;
     const void* dictContent;
     size_t dictSize;
     ZSTD_entropyDTables_t entropy;
     U32 dictID;
     U32 entropyPresent;
     ZSTD_customMem cMem;
 };  /* typedef'd to ZSTD_DDict within "zstd.h" */
 
 static const void* ZSTD_DDictDictContent(const ZSTD_DDict* ddict)
 {
     return ddict->dictContent;
 }
 
 static size_t ZSTD_DDictDictSize(const ZSTD_DDict* ddict)
 {
     return ddict->dictSize;
 }
 
 size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dstDCtx, const ZSTD_DDict* ddict)
 {
     CHECK_F( ZSTD_decompressBegin(dstDCtx) );
     if (ddict) {   /* support begin on NULL */
         dstDCtx->dictID = ddict->dictID;
         dstDCtx->base = ddict->dictContent;
         dstDCtx->vBase = ddict->dictContent;
         dstDCtx->dictEnd = (const BYTE*)ddict->dictContent + ddict->dictSize;
         dstDCtx->previousDstEnd = dstDCtx->dictEnd;
         if (ddict->entropyPresent) {
             dstDCtx->litEntropy = 1;
             dstDCtx->fseEntropy = 1;
             dstDCtx->LLTptr = ddict->entropy.LLTable;
             dstDCtx->MLTptr = ddict->entropy.MLTable;
             dstDCtx->OFTptr = ddict->entropy.OFTable;
             dstDCtx->HUFptr = ddict->entropy.hufTable;
             dstDCtx->entropy.rep[0] = ddict->entropy.rep[0];
             dstDCtx->entropy.rep[1] = ddict->entropy.rep[1];
             dstDCtx->entropy.rep[2] = ddict->entropy.rep[2];
         } else {
             dstDCtx->litEntropy = 0;
             dstDCtx->fseEntropy = 0;
         }
     }
     return 0;
 }
 
 static size_t ZSTD_loadEntropy_inDDict(ZSTD_DDict* ddict)
 {
     ddict->dictID = 0;
     ddict->entropyPresent = 0;
     if (ddict->dictSize < 8) return 0;
     {   U32 const magic = MEM_readLE32(ddict->dictContent);
         if (magic != ZSTD_MAGIC_DICTIONARY) return 0;   /* pure content mode */
     }
     ddict->dictID = MEM_readLE32((const char*)ddict->dictContent + ZSTD_frameIdSize);
 
     /* load entropy tables */
     CHECK_E( ZSTD_loadEntropy(&ddict->entropy, ddict->dictContent, ddict->dictSize), dictionary_corrupted );
     ddict->entropyPresent = 1;
     return 0;
 }
 
 
 static size_t ZSTD_initDDict_internal(ZSTD_DDict* ddict, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod)
 {
     if ((dictLoadMethod == ZSTD_dlm_byRef) || (!dict) || (!dictSize)) {
         ddict->dictBuffer = NULL;
         ddict->dictContent = dict;
     } else {
         void* const internalBuffer = ZSTD_malloc(dictSize, ddict->cMem);
         ddict->dictBuffer = internalBuffer;
         ddict->dictContent = internalBuffer;
         if (!internalBuffer) return ERROR(memory_allocation);
         memcpy(internalBuffer, dict, dictSize);
     }
     ddict->dictSize = dictSize;
     ddict->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001);  /* cover both little and big endian */
 
     /* parse dictionary content */
     CHECK_F( ZSTD_loadEntropy_inDDict(ddict) );
 
     return 0;
 }
 
 ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_customMem customMem)
 {
     if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
 
     {   ZSTD_DDict* const ddict = (ZSTD_DDict*) ZSTD_malloc(sizeof(ZSTD_DDict), customMem);
         if (!ddict) return NULL;
         ddict->cMem = customMem;
 
         if (ZSTD_isError( ZSTD_initDDict_internal(ddict, dict, dictSize, dictLoadMethod) )) {
             ZSTD_freeDDict(ddict);
             return NULL;
         }
 
         return ddict;
     }
 }
 
 /*! ZSTD_createDDict() :
 *   Create a digested dictionary, to start decompression without startup delay.
 *   `dict` content is copied inside DDict.
 *   Consequently, `dict` can be released after `ZSTD_DDict` creation */
 ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize)
 {
     ZSTD_customMem const allocator = { NULL, NULL, NULL };
     return ZSTD_createDDict_advanced(dict, dictSize, ZSTD_dlm_byCopy, allocator);
 }
 
 /*! ZSTD_createDDict_byReference() :
  *  Create a digested dictionary, to start decompression without startup delay.
  *  Dictionary content is simply referenced, it will be accessed during decompression.
  *  Warning : dictBuffer must outlive DDict (DDict must be freed before dictBuffer) */
 ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize)
 {
     ZSTD_customMem const allocator = { NULL, NULL, NULL };
     return ZSTD_createDDict_advanced(dictBuffer, dictSize, ZSTD_dlm_byRef, allocator);
 }
 
 
 ZSTD_DDict* ZSTD_initStaticDDict(void* workspace, size_t workspaceSize,
                                  const void* dict, size_t dictSize,
                                  ZSTD_dictLoadMethod_e dictLoadMethod)
 {
     size_t const neededSpace =
             sizeof(ZSTD_DDict) + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
     ZSTD_DDict* const ddict = (ZSTD_DDict*)workspace;
     assert(workspace != NULL);
     assert(dict != NULL);
     if ((size_t)workspace & 7) return NULL;  /* 8-aligned */
     if (workspaceSize < neededSpace) return NULL;
     if (dictLoadMethod == ZSTD_dlm_byCopy) {
         memcpy(ddict+1, dict, dictSize);  /* local copy */
         dict = ddict+1;
     }
     if (ZSTD_isError( ZSTD_initDDict_internal(ddict, dict, dictSize, ZSTD_dlm_byRef) ))
         return NULL;
     return ddict;
 }
 
 
 size_t ZSTD_freeDDict(ZSTD_DDict* ddict)
 {
     if (ddict==NULL) return 0;   /* support free on NULL */
     {   ZSTD_customMem const cMem = ddict->cMem;
         ZSTD_free(ddict->dictBuffer, cMem);
         ZSTD_free(ddict, cMem);
         return 0;
     }
 }
 
 /*! ZSTD_estimateDDictSize() :
  *  Estimate amount of memory that will be needed to create a dictionary for decompression.
  *  Note : dictionary created by reference using ZSTD_dlm_byRef are smaller */
 size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod)
 {
     return sizeof(ZSTD_DDict) + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
 }
 
 size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict)
 {
     if (ddict==NULL) return 0;   /* support sizeof on NULL */
     return sizeof(*ddict) + (ddict->dictBuffer ? ddict->dictSize : 0) ;
 }
 
 /*! ZSTD_getDictID_fromDict() :
  *  Provides the dictID stored within dictionary.
  *  if @return == 0, the dictionary is not conformant with Zstandard specification.
  *  It can still be loaded, but as a content-only dictionary. */
 unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize)
 {
     if (dictSize < 8) return 0;
     if (MEM_readLE32(dict) != ZSTD_MAGIC_DICTIONARY) return 0;
     return MEM_readLE32((const char*)dict + ZSTD_frameIdSize);
 }
 
 /*! ZSTD_getDictID_fromDDict() :
  *  Provides the dictID of the dictionary loaded into `ddict`.
  *  If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
  *  Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
 unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict)
 {
     if (ddict==NULL) return 0;
     return ZSTD_getDictID_fromDict(ddict->dictContent, ddict->dictSize);
 }
 
 /*! ZSTD_getDictID_fromFrame() :
  *  Provides the dictID required to decompresse frame stored within `src`.
  *  If @return == 0, the dictID could not be decoded.
  *  This could for one of the following reasons :
  *  - The frame does not require a dictionary (most common case).
  *  - The frame was built with dictID intentionally removed.
  *    Needed dictionary is a hidden information.
  *    Note : this use case also happens when using a non-conformant dictionary.
  *  - `srcSize` is too small, and as a result, frame header could not be decoded.
  *    Note : possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`.
  *  - This is not a Zstandard frame.
  *  When identifying the exact failure cause, it's possible to use
  *  ZSTD_getFrameHeader(), which will provide a more precise error code. */
 unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize)
 {
     ZSTD_frameHeader zfp = { 0, 0, 0, ZSTD_frame, 0, 0, 0 };
     size_t const hError = ZSTD_getFrameHeader(&zfp, src, srcSize);
     if (ZSTD_isError(hError)) return 0;
     return zfp.dictID;
 }
 
 
 /*! ZSTD_decompress_usingDDict() :
 *   Decompression using a pre-digested Dictionary
 *   Use dictionary without significant overhead. */
 size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
                                   void* dst, size_t dstCapacity,
                             const void* src, size_t srcSize,
                             const ZSTD_DDict* ddict)
 {
     /* pass content and size in case legacy frames are encountered */
     return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize,
                                      NULL, 0,
                                      ddict);
 }
 
 
 /*=====================================
 *   Streaming decompression
 *====================================*/
 
 ZSTD_DStream* ZSTD_createDStream(void)
 {
     return ZSTD_createDStream_advanced(ZSTD_defaultCMem);
 }
 
 ZSTD_DStream* ZSTD_initStaticDStream(void *workspace, size_t workspaceSize)
 {
     return ZSTD_initStaticDCtx(workspace, workspaceSize);
 }
 
 ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem)
 {
     return ZSTD_createDCtx_advanced(customMem);
 }
 
 size_t ZSTD_freeDStream(ZSTD_DStream* zds)
 {
     return ZSTD_freeDCtx(zds);
 }
 
 
 /* *** Initialization *** */
 
 size_t ZSTD_DStreamInSize(void)  { return ZSTD_BLOCKSIZE_MAX + ZSTD_blockHeaderSize; }
 size_t ZSTD_DStreamOutSize(void) { return ZSTD_BLOCKSIZE_MAX; }
 
 size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize)
 {
     zds->streamStage = zdss_loadHeader;
     zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
     ZSTD_freeDDict(zds->ddictLocal);
     if (dict && dictSize >= 8) {
         zds->ddictLocal = ZSTD_createDDict(dict, dictSize);
         if (zds->ddictLocal == NULL) return ERROR(memory_allocation);
     } else zds->ddictLocal = NULL;
     zds->ddict = zds->ddictLocal;
     zds->legacyVersion = 0;
     zds->hostageByte = 0;
     return ZSTD_frameHeaderSize_prefix;
 }
 
 /* note : this variant can't fail */
 size_t ZSTD_initDStream(ZSTD_DStream* zds)
 {
     return ZSTD_initDStream_usingDict(zds, NULL, 0);
 }
 
 /* ZSTD_initDStream_usingDDict() :
  * ddict will just be referenced, and must outlive decompression session
  * this function cannot fail */
 size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict)
 {
     size_t const initResult = ZSTD_initDStream(zds);
     zds->ddict = ddict;
     return initResult;
 }
 
 size_t ZSTD_resetDStream(ZSTD_DStream* zds)
 {
     zds->streamStage = zdss_loadHeader;
     zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
     zds->legacyVersion = 0;
     zds->hostageByte = 0;
     return ZSTD_frameHeaderSize_prefix;
 }
 
 size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds,
                                 ZSTD_DStreamParameter_e paramType, unsigned paramValue)
 {
     ZSTD_STATIC_ASSERT((unsigned)zdss_loadHeader >= (unsigned)zdss_init);
     if ((unsigned)zds->streamStage > (unsigned)zdss_loadHeader)
         return ERROR(stage_wrong);
     switch(paramType)
     {
         default : return ERROR(parameter_unsupported);
         case DStream_p_maxWindowSize :
             DEBUGLOG(4, "setting maxWindowSize = %u KB", paramValue >> 10);
             zds->maxWindowSize = paramValue ? paramValue : (U32)(-1);
             break;
     }
     return 0;
 }
 
 size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize)
 {
     ZSTD_STATIC_ASSERT((unsigned)zdss_loadHeader >= (unsigned)zdss_init);
     if ((unsigned)dctx->streamStage > (unsigned)zdss_loadHeader)
         return ERROR(stage_wrong);
     dctx->maxWindowSize = maxWindowSize;
     return 0;
 }
 
 size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format)
 {
     DEBUGLOG(4, "ZSTD_DCtx_setFormat : %u", (unsigned)format);
     ZSTD_STATIC_ASSERT((unsigned)zdss_loadHeader >= (unsigned)zdss_init);
     if ((unsigned)dctx->streamStage > (unsigned)zdss_loadHeader)
         return ERROR(stage_wrong);
     dctx->format = format;
     return 0;
 }
 
 
 size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds)
 {
     return ZSTD_sizeof_DCtx(zds);
 }
 
 size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize)
 {
     size_t const blockSize = (size_t) MIN(windowSize, ZSTD_BLOCKSIZE_MAX);
     unsigned long long const neededRBSize = windowSize + blockSize + (WILDCOPY_OVERLENGTH * 2);
     unsigned long long const neededSize = MIN(frameContentSize, neededRBSize);
     size_t const minRBSize = (size_t) neededSize;
     if ((unsigned long long)minRBSize != neededSize) return ERROR(frameParameter_windowTooLarge);
     return minRBSize;
 }
 
 size_t ZSTD_estimateDStreamSize(size_t windowSize)
 {
     size_t const blockSize = MIN(windowSize, ZSTD_BLOCKSIZE_MAX);
     size_t const inBuffSize = blockSize;  /* no block can be larger */
     size_t const outBuffSize = ZSTD_decodingBufferSize_min(windowSize, ZSTD_CONTENTSIZE_UNKNOWN);
     return ZSTD_estimateDCtxSize() + inBuffSize + outBuffSize;
 }
 
 size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize)
 {
     U32 const windowSizeMax = 1U << ZSTD_WINDOWLOG_MAX;   /* note : should be user-selectable */
     ZSTD_frameHeader zfh;
     size_t const err = ZSTD_getFrameHeader(&zfh, src, srcSize);
     if (ZSTD_isError(err)) return err;
     if (err>0) return ERROR(srcSize_wrong);
     if (zfh.windowSize > windowSizeMax)
         return ERROR(frameParameter_windowTooLarge);
     return ZSTD_estimateDStreamSize((size_t)zfh.windowSize);
 }
 
 
 /* *****   Decompression   ***** */
 
 MEM_STATIC size_t ZSTD_limitCopy(void* dst, size_t dstCapacity, const void* src, size_t srcSize)
 {
     size_t const length = MIN(dstCapacity, srcSize);
     memcpy(dst, src, length);
     return length;
 }
 
 
 size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
 {
     const char* const istart = (const char*)(input->src) + input->pos;
     const char* const iend = (const char*)(input->src) + input->size;
     const char* ip = istart;
     char* const ostart = (char*)(output->dst) + output->pos;
     char* const oend = (char*)(output->dst) + output->size;
     char* op = ostart;
     U32 someMoreWork = 1;
 
     DEBUGLOG(5, "ZSTD_decompressStream");
     if (input->pos > input->size) {  /* forbidden */
         DEBUGLOG(5, "in: pos: %u   vs size: %u",
                     (U32)input->pos, (U32)input->size);
         return ERROR(srcSize_wrong);
     }
     if (output->pos > output->size) {  /* forbidden */
         DEBUGLOG(5, "out: pos: %u   vs size: %u",
                     (U32)output->pos, (U32)output->size);
         return ERROR(dstSize_tooSmall);
     }
     DEBUGLOG(5, "input size : %u", (U32)(input->size - input->pos));
 
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
     if (zds->legacyVersion) {
         /* legacy support is incompatible with static dctx */
         if (zds->staticSize) return ERROR(memory_allocation);
         return ZSTD_decompressLegacyStream(zds->legacyContext, zds->legacyVersion, output, input);
     }
 #endif
 
     while (someMoreWork) {
         switch(zds->streamStage)
         {
         case zdss_init :
             ZSTD_resetDStream(zds);   /* transparent reset on starting decoding a new frame */
             /* fall-through */
 
         case zdss_loadHeader :
             DEBUGLOG(5, "stage zdss_loadHeader (srcSize : %u)", (U32)(iend - ip));
             {   size_t const hSize = ZSTD_getFrameHeader_internal(&zds->fParams, zds->headerBuffer, zds->lhSize, zds->format);
                 DEBUGLOG(5, "header size : %u", (U32)hSize);
                 if (ZSTD_isError(hSize)) {
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
                     U32 const legacyVersion = ZSTD_isLegacy(istart, iend-istart);
                     if (legacyVersion) {
                         const void* const dict = zds->ddict ? zds->ddict->dictContent : NULL;
                         size_t const dictSize = zds->ddict ? zds->ddict->dictSize : 0;
                         /* legacy support is incompatible with static dctx */
                         if (zds->staticSize) return ERROR(memory_allocation);
                         CHECK_F(ZSTD_initLegacyStream(&zds->legacyContext,
                                     zds->previousLegacyVersion, legacyVersion,
                                     dict, dictSize));
                         zds->legacyVersion = zds->previousLegacyVersion = legacyVersion;
                         return ZSTD_decompressLegacyStream(zds->legacyContext, legacyVersion, output, input);
                     }
 #endif
-                    return hSize; /* error */
+                    return hSize;   /* error */
                 }
                 if (hSize != 0) {   /* need more input */
                     size_t const toLoad = hSize - zds->lhSize;   /* if hSize!=0, hSize > zds->lhSize */
-                    if (toLoad > (size_t)(iend-ip)) {   /* not enough input to load full header */
-                        if (iend-ip > 0) {
-                            memcpy(zds->headerBuffer + zds->lhSize, ip, iend-ip);
-                            zds->lhSize += iend-ip;
+                    size_t const remainingInput = (size_t)(iend-ip);
+                    assert(iend >= ip);
+                    if (toLoad > remainingInput) {   /* not enough input to load full header */
+                        if (remainingInput > 0) {
+                            memcpy(zds->headerBuffer + zds->lhSize, ip, remainingInput);
+                            zds->lhSize += remainingInput;
                         }
                         input->pos = input->size;
                         return (MAX(ZSTD_frameHeaderSize_min, hSize) - zds->lhSize) + ZSTD_blockHeaderSize;   /* remaining header bytes + next block header */
                     }
                     assert(ip != NULL);
                     memcpy(zds->headerBuffer + zds->lhSize, ip, toLoad); zds->lhSize = hSize; ip += toLoad;
                     break;
             }   }
 
             /* check for single-pass mode opportunity */
             if (zds->fParams.frameContentSize && zds->fParams.windowSize /* skippable frame if == 0 */
                 && (U64)(size_t)(oend-op) >= zds->fParams.frameContentSize) {
                 size_t const cSize = ZSTD_findFrameCompressedSize(istart, iend-istart);
                 if (cSize <= (size_t)(iend-istart)) {
+                    /* shortcut : using single-pass mode */
                     size_t const decompressedSize = ZSTD_decompress_usingDDict(zds, op, oend-op, istart, cSize, zds->ddict);
                     if (ZSTD_isError(decompressedSize)) return decompressedSize;
+                    DEBUGLOG(4, "shortcut to single-pass ZSTD_decompress_usingDDict()")
                     ip = istart + cSize;
                     op += decompressedSize;
                     zds->expected = 0;
                     zds->streamStage = zdss_init;
                     someMoreWork = 0;
                     break;
             }   }
 
             /* Consume header (see ZSTDds_decodeFrameHeader) */
             DEBUGLOG(4, "Consume header");
             CHECK_F(ZSTD_decompressBegin_usingDDict(zds, zds->ddict));
 
             if ((MEM_readLE32(zds->headerBuffer) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {  /* skippable frame */
                 zds->expected = MEM_readLE32(zds->headerBuffer + ZSTD_frameIdSize);
                 zds->stage = ZSTDds_skipFrame;
             } else {
                 CHECK_F(ZSTD_decodeFrameHeader(zds, zds->headerBuffer, zds->lhSize));
                 zds->expected = ZSTD_blockHeaderSize;
                 zds->stage = ZSTDds_decodeBlockHeader;
             }
 
             /* control buffer memory usage */
-            DEBUGLOG(4, "Control max buffer memory usage (max %u KB)",
-                        (U32)(zds->maxWindowSize >> 10));
+            DEBUGLOG(4, "Control max memory usage (%u KB <= max %u KB)",
+                        (U32)(zds->fParams.windowSize >>10),
+                        (U32)(zds->maxWindowSize >> 10) );
             zds->fParams.windowSize = MAX(zds->fParams.windowSize, 1U << ZSTD_WINDOWLOG_ABSOLUTEMIN);
             if (zds->fParams.windowSize > zds->maxWindowSize) return ERROR(frameParameter_windowTooLarge);
 
             /* Adapt buffer sizes to frame header instructions */
             {   size_t const neededInBuffSize = MAX(zds->fParams.blockSizeMax, 4 /* frame checksum */);
                 size_t const neededOutBuffSize = ZSTD_decodingBufferSize_min(zds->fParams.windowSize, zds->fParams.frameContentSize);
                 if ((zds->inBuffSize < neededInBuffSize) || (zds->outBuffSize < neededOutBuffSize)) {
                     size_t const bufferSize = neededInBuffSize + neededOutBuffSize;
                     DEBUGLOG(4, "inBuff  : from %u to %u",
                                 (U32)zds->inBuffSize, (U32)neededInBuffSize);
                     DEBUGLOG(4, "outBuff : from %u to %u",
                                 (U32)zds->outBuffSize, (U32)neededOutBuffSize);
                     if (zds->staticSize) {  /* static DCtx */
                         DEBUGLOG(4, "staticSize : %u", (U32)zds->staticSize);
                         assert(zds->staticSize >= sizeof(ZSTD_DCtx));  /* controlled at init */
                         if (bufferSize > zds->staticSize - sizeof(ZSTD_DCtx))
                             return ERROR(memory_allocation);
                     } else {
                         ZSTD_free(zds->inBuff, zds->customMem);
                         zds->inBuffSize = 0;
                         zds->outBuffSize = 0;
                         zds->inBuff = (char*)ZSTD_malloc(bufferSize, zds->customMem);
                         if (zds->inBuff == NULL) return ERROR(memory_allocation);
                     }
                     zds->inBuffSize = neededInBuffSize;
                     zds->outBuff = zds->inBuff + zds->inBuffSize;
                     zds->outBuffSize = neededOutBuffSize;
             }   }
             zds->streamStage = zdss_read;
             /* fall-through */
 
         case zdss_read:
             DEBUGLOG(5, "stage zdss_read");
             {   size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds);
                 DEBUGLOG(5, "neededInSize = %u", (U32)neededInSize);
                 if (neededInSize==0) {  /* end of frame */
                     zds->streamStage = zdss_init;
                     someMoreWork = 0;
                     break;
                 }
                 if ((size_t)(iend-ip) >= neededInSize) {  /* decode directly from src */
                     int const isSkipFrame = ZSTD_isSkipFrame(zds);
                     size_t const decodedSize = ZSTD_decompressContinue(zds,
                         zds->outBuff + zds->outStart, (isSkipFrame ? 0 : zds->outBuffSize - zds->outStart),
                         ip, neededInSize);
                     if (ZSTD_isError(decodedSize)) return decodedSize;
                     ip += neededInSize;
                     if (!decodedSize && !isSkipFrame) break;   /* this was just a header */
                     zds->outEnd = zds->outStart + decodedSize;
                     zds->streamStage = zdss_flush;
                     break;
             }   }
             if (ip==iend) { someMoreWork = 0; break; }   /* no more input */
             zds->streamStage = zdss_load;
             /* fall-through */
         case zdss_load:
             {   size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds);
-                size_t const toLoad = neededInSize - zds->inPos;   /* should always be <= remaining space within inBuff */
+                size_t const toLoad = neededInSize - zds->inPos;
+                int const isSkipFrame = ZSTD_isSkipFrame(zds);
                 size_t loadedSize;
-                if (toLoad > zds->inBuffSize - zds->inPos) return ERROR(corruption_detected);   /* should never happen */
-                loadedSize = ZSTD_limitCopy(zds->inBuff + zds->inPos, toLoad, ip, iend-ip);
+                if (isSkipFrame) {
+                    loadedSize = MIN(toLoad, (size_t)(iend-ip));
+                } else {
+                    if (toLoad > zds->inBuffSize - zds->inPos) return ERROR(corruption_detected);   /* should never happen */
+                    loadedSize = ZSTD_limitCopy(zds->inBuff + zds->inPos, toLoad, ip, iend-ip);
+                }
                 ip += loadedSize;
                 zds->inPos += loadedSize;
                 if (loadedSize < toLoad) { someMoreWork = 0; break; }   /* not enough input, wait for more */
 
                 /* decode loaded input */
-                {  const int isSkipFrame = ZSTD_isSkipFrame(zds);
-                   size_t const decodedSize = ZSTD_decompressContinue(zds,
+                {   size_t const decodedSize = ZSTD_decompressContinue(zds,
                         zds->outBuff + zds->outStart, zds->outBuffSize - zds->outStart,
                         zds->inBuff, neededInSize);
                     if (ZSTD_isError(decodedSize)) return decodedSize;
                     zds->inPos = 0;   /* input is consumed */
                     if (!decodedSize && !isSkipFrame) { zds->streamStage = zdss_read; break; }   /* this was just a header */
                     zds->outEnd = zds->outStart +  decodedSize;
             }   }
             zds->streamStage = zdss_flush;
             /* fall-through */
         case zdss_flush:
             {   size_t const toFlushSize = zds->outEnd - zds->outStart;
                 size_t const flushedSize = ZSTD_limitCopy(op, oend-op, zds->outBuff + zds->outStart, toFlushSize);
                 op += flushedSize;
                 zds->outStart += flushedSize;
                 if (flushedSize == toFlushSize) {  /* flush completed */
                     zds->streamStage = zdss_read;
                     if ( (zds->outBuffSize < zds->fParams.frameContentSize)
                       && (zds->outStart + zds->fParams.blockSizeMax > zds->outBuffSize) ) {
                         DEBUGLOG(5, "restart filling outBuff from beginning (left:%i, needed:%u)",
                                 (int)(zds->outBuffSize - zds->outStart),
                                 (U32)zds->fParams.blockSizeMax);
                         zds->outStart = zds->outEnd = 0;
                     }
                     break;
             }   }
             /* cannot complete flush */
             someMoreWork = 0;
             break;
 
         default: return ERROR(GENERIC);   /* impossible */
     }   }
 
     /* result */
     input->pos += (size_t)(ip-istart);
     output->pos += (size_t)(op-ostart);
     {   size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(zds);
         if (!nextSrcSizeHint) {   /* frame fully decoded */
             if (zds->outEnd == zds->outStart) {  /* output fully flushed */
                 if (zds->hostageByte) {
                     if (input->pos >= input->size) {
                         /* can't release hostage (not present) */
                         zds->streamStage = zdss_read;
                         return 1;
                     }
                     input->pos++;  /* release hostage */
                 }   /* zds->hostageByte */
                 return 0;
             }  /* zds->outEnd == zds->outStart */
             if (!zds->hostageByte) { /* output not fully flushed; keep last byte as hostage; will be released when all output is flushed */
                 input->pos--;   /* note : pos > 0, otherwise, impossible to finish reading last block */
                 zds->hostageByte=1;
             }
             return 1;
         }  /* nextSrcSizeHint==0 */
         nextSrcSizeHint += ZSTD_blockHeaderSize * (ZSTD_nextInputType(zds) == ZSTDnit_block);   /* preload header of next block */
         if (zds->inPos > nextSrcSizeHint) return ERROR(GENERIC);   /* should never happen */
         nextSrcSizeHint -= zds->inPos;   /* already loaded*/
         return nextSrcSizeHint;
     }
 }
 
 
 size_t ZSTD_decompress_generic(ZSTD_DCtx* dctx, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
 {
     return ZSTD_decompressStream(dctx, output, input);
 }
 
 size_t ZSTD_decompress_generic_simpleArgs (
                             ZSTD_DCtx* dctx,
                             void* dst, size_t dstCapacity, size_t* dstPos,
                       const void* src, size_t srcSize, size_t* srcPos)
 {
     ZSTD_outBuffer output = { dst, dstCapacity, *dstPos };
     ZSTD_inBuffer  input  = { src, srcSize, *srcPos };
     /* ZSTD_compress_generic() will check validity of dstPos and srcPos */
     size_t const cErr = ZSTD_decompress_generic(dctx, &output, &input);
     *dstPos = output.pos;
     *srcPos = input.pos;
     return cErr;
 }
 
 void ZSTD_DCtx_reset(ZSTD_DCtx* dctx)
 {
     (void)ZSTD_initDStream(dctx);
     dctx->format = ZSTD_f_zstd1;
     dctx->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT;
 }
Index: head/sys/contrib/zstd/lib/deprecated/zbuff_compress.c
===================================================================
--- head/sys/contrib/zstd/lib/deprecated/zbuff_compress.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/deprecated/zbuff_compress.c	(revision 330894)
@@ -1,146 +1,147 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 
 
 /* *************************************
 *  Dependencies
 ***************************************/
 #define ZBUFF_STATIC_LINKING_ONLY
 #include "zbuff.h"
 
 
 /*-***********************************************************
 *  Streaming compression
 *
 *  A ZBUFF_CCtx object is required to track streaming operation.
 *  Use ZBUFF_createCCtx() and ZBUFF_freeCCtx() to create/release resources.
 *  Use ZBUFF_compressInit() to start a new compression operation.
 *  ZBUFF_CCtx objects can be reused multiple times.
 *
 *  Use ZBUFF_compressContinue() repetitively to consume your input.
 *  *srcSizePtr and *dstCapacityPtr can be any size.
 *  The function will report how many bytes were read or written by modifying *srcSizePtr and *dstCapacityPtr.
 *  Note that it may not consume the entire input, in which case it's up to the caller to call again the function with remaining input.
 *  The content of dst will be overwritten (up to *dstCapacityPtr) at each function call, so save its content if it matters or change dst .
 *  @return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to improve latency)
 *            or an error code, which can be tested using ZBUFF_isError().
 *
 *  ZBUFF_compressFlush() can be used to instruct ZBUFF to compress and output whatever remains within its buffer.
 *  Note that it will not output more than *dstCapacityPtr.
 *  Therefore, some content might still be left into its internal buffer if dst buffer is too small.
 *  @return : nb of bytes still present into internal buffer (0 if it's empty)
 *            or an error code, which can be tested using ZBUFF_isError().
 *
 *  ZBUFF_compressEnd() instructs to finish a frame.
 *  It will perform a flush and write frame epilogue.
 *  Similar to ZBUFF_compressFlush(), it may not be able to output the entire internal buffer content if *dstCapacityPtr is too small.
 *  @return : nb of bytes still present into internal buffer (0 if it's empty)
 *            or an error code, which can be tested using ZBUFF_isError().
 *
 *  Hint : recommended buffer sizes (not compulsory)
 *  input : ZSTD_BLOCKSIZE_MAX (128 KB), internal unit size, it improves latency to use this value.
 *  output : ZSTD_compressBound(ZSTD_BLOCKSIZE_MAX) + ZSTD_blockHeaderSize + ZBUFF_endFrameSize : ensures it's always possible to write/flush/end a full block at best speed.
 * ***********************************************************/
 
 ZBUFF_CCtx* ZBUFF_createCCtx(void)
 {
     return ZSTD_createCStream();
 }
 
 ZBUFF_CCtx* ZBUFF_createCCtx_advanced(ZSTD_customMem customMem)
 {
     return ZSTD_createCStream_advanced(customMem);
 }
 
 size_t ZBUFF_freeCCtx(ZBUFF_CCtx* zbc)
 {
     return ZSTD_freeCStream(zbc);
 }
 
 
 /* ======   Initialization   ====== */
 
 size_t ZBUFF_compressInit_advanced(ZBUFF_CCtx* zbc,
                                    const void* dict, size_t dictSize,
                                    ZSTD_parameters params, unsigned long long pledgedSrcSize)
 {
+    if (pledgedSrcSize==0) pledgedSrcSize = ZSTD_CONTENTSIZE_UNKNOWN;  /* preserve "0 == unknown" behavior */
     return ZSTD_initCStream_advanced(zbc, dict, dictSize, params, pledgedSrcSize);
 }
 
 
 size_t ZBUFF_compressInitDictionary(ZBUFF_CCtx* zbc, const void* dict, size_t dictSize, int compressionLevel)
 {
     return ZSTD_initCStream_usingDict(zbc, dict, dictSize, compressionLevel);
 }
 
 size_t ZBUFF_compressInit(ZBUFF_CCtx* zbc, int compressionLevel)
 {
     return ZSTD_initCStream(zbc, compressionLevel);
 }
 
 /* ======   Compression   ====== */
 
 
 size_t ZBUFF_compressContinue(ZBUFF_CCtx* zbc,
                               void* dst, size_t* dstCapacityPtr,
                         const void* src, size_t* srcSizePtr)
 {
     size_t result;
     ZSTD_outBuffer outBuff;
     ZSTD_inBuffer inBuff;
     outBuff.dst = dst;
     outBuff.pos = 0;
     outBuff.size = *dstCapacityPtr;
     inBuff.src = src;
     inBuff.pos = 0;
     inBuff.size = *srcSizePtr;
     result = ZSTD_compressStream(zbc, &outBuff, &inBuff);
     *dstCapacityPtr = outBuff.pos;
     *srcSizePtr = inBuff.pos;
     return result;
 }
 
 
 
 /* ======   Finalize   ====== */
 
 size_t ZBUFF_compressFlush(ZBUFF_CCtx* zbc, void* dst, size_t* dstCapacityPtr)
 {
     size_t result;
     ZSTD_outBuffer outBuff;
     outBuff.dst = dst;
     outBuff.pos = 0;
     outBuff.size = *dstCapacityPtr;
     result = ZSTD_flushStream(zbc, &outBuff);
     *dstCapacityPtr = outBuff.pos;
     return result;
 }
 
 
 size_t ZBUFF_compressEnd(ZBUFF_CCtx* zbc, void* dst, size_t* dstCapacityPtr)
 {
     size_t result;
     ZSTD_outBuffer outBuff;
     outBuff.dst = dst;
     outBuff.pos = 0;
     outBuff.size = *dstCapacityPtr;
     result = ZSTD_endStream(zbc, &outBuff);
     *dstCapacityPtr = outBuff.pos;
     return result;
 }
 
 
 
 /* *************************************
 *  Tool functions
 ***************************************/
 size_t ZBUFF_recommendedCInSize(void)  { return ZSTD_CStreamInSize(); }
 size_t ZBUFF_recommendedCOutSize(void) { return ZSTD_CStreamOutSize(); }
Index: head/sys/contrib/zstd/lib/dictBuilder/zdict.c
===================================================================
--- head/sys/contrib/zstd/lib/dictBuilder/zdict.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/dictBuilder/zdict.c	(revision 330894)
@@ -1,1075 +1,1075 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 
 /*-**************************************
 *  Tuning parameters
 ****************************************/
 #define MINRATIO 4   /* minimum nb of apparition to be selected in dictionary */
 #define ZDICT_MAX_SAMPLES_SIZE (2000U << 20)
 #define ZDICT_MIN_SAMPLES_SIZE (ZDICT_CONTENTSIZE_MIN * MINRATIO)
 
 
 /*-**************************************
 *  Compiler Options
 ****************************************/
 /* Unix Large Files support (>4GB) */
 #define _FILE_OFFSET_BITS 64
 #if (defined(__sun__) && (!defined(__LP64__)))   /* Sun Solaris 32-bits requires specific definitions */
 #  define _LARGEFILE_SOURCE
 #elif ! defined(__LP64__)                        /* No point defining Large file for 64 bit */
 #  define _LARGEFILE64_SOURCE
 #endif
 
 
 /*-*************************************
 *  Dependencies
 ***************************************/
 #include         /* malloc, free */
 #include         /* memset */
 #include          /* fprintf, fopen, ftello64 */
 #include           /* clock */
 
 #include "mem.h"           /* read */
 #include "fse.h"           /* FSE_normalizeCount, FSE_writeNCount */
 #define HUF_STATIC_LINKING_ONLY
 #include "huf.h"           /* HUF_buildCTable, HUF_writeCTable */
 #include "zstd_internal.h" /* includes zstd.h */
 #include "xxhash.h"        /* XXH64 */
 #include "divsufsort.h"
 #ifndef ZDICT_STATIC_LINKING_ONLY
 #  define ZDICT_STATIC_LINKING_ONLY
 #endif
 #include "zdict.h"
 
 
 /*-*************************************
 *  Constants
 ***************************************/
 #define KB *(1 <<10)
 #define MB *(1 <<20)
 #define GB *(1U<<30)
 
 #define DICTLISTSIZE_DEFAULT 10000
 
 #define NOISELENGTH 32
 
 static const int g_compressionLevel_default = 3;
 static const U32 g_selectivity_default = 9;
 
 
 /*-*************************************
 *  Console display
 ***************************************/
 #define DISPLAY(...)         { fprintf(stderr, __VA_ARGS__); fflush( stderr ); }
 #define DISPLAYLEVEL(l, ...) if (notificationLevel>=l) { DISPLAY(__VA_ARGS__); }    /* 0 : no display;   1: errors;   2: default;  3: details;  4: debug */
 
 static clock_t ZDICT_clockSpan(clock_t nPrevious) { return clock() - nPrevious; }
 
 static void ZDICT_printHex(const void* ptr, size_t length)
 {
     const BYTE* const b = (const BYTE*)ptr;
     size_t u;
     for (u=0; u126) c = '.';   /* non-printable char */
         DISPLAY("%c", c);
     }
 }
 
 
 /*-********************************************************
 *  Helper functions
 **********************************************************/
 unsigned ZDICT_isError(size_t errorCode) { return ERR_isError(errorCode); }
 
 const char* ZDICT_getErrorName(size_t errorCode) { return ERR_getErrorName(errorCode); }
 
 unsigned ZDICT_getDictID(const void* dictBuffer, size_t dictSize)
 {
     if (dictSize < 8) return 0;
     if (MEM_readLE32(dictBuffer) != ZSTD_MAGIC_DICTIONARY) return 0;
     return MEM_readLE32((const char*)dictBuffer + 4);
 }
 
 
 /*-********************************************************
 *  Dictionary training functions
 **********************************************************/
-static unsigned ZDICT_NbCommonBytes (register size_t val)
+static unsigned ZDICT_NbCommonBytes (size_t val)
 {
     if (MEM_isLittleEndian()) {
         if (MEM_64bits()) {
 #       if defined(_MSC_VER) && defined(_WIN64)
             unsigned long r = 0;
             _BitScanForward64( &r, (U64)val );
             return (unsigned)(r>>3);
 #       elif defined(__GNUC__) && (__GNUC__ >= 3)
             return (__builtin_ctzll((U64)val) >> 3);
 #       else
             static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };
             return DeBruijnBytePos[((U64)((val & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58];
 #       endif
         } else { /* 32 bits */
 #       if defined(_MSC_VER)
             unsigned long r=0;
             _BitScanForward( &r, (U32)val );
             return (unsigned)(r>>3);
 #       elif defined(__GNUC__) && (__GNUC__ >= 3)
             return (__builtin_ctz((U32)val) >> 3);
 #       else
             static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
             return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
 #       endif
         }
     } else {  /* Big Endian CPU */
         if (MEM_64bits()) {
 #       if defined(_MSC_VER) && defined(_WIN64)
             unsigned long r = 0;
             _BitScanReverse64( &r, val );
             return (unsigned)(r>>3);
 #       elif defined(__GNUC__) && (__GNUC__ >= 3)
             return (__builtin_clzll(val) >> 3);
 #       else
             unsigned r;
             const unsigned n32 = sizeof(size_t)*4;   /* calculate this way due to compiler complaining in 32-bits mode */
             if (!(val>>n32)) { r=4; } else { r=0; val>>=n32; }
             if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
             r += (!val);
             return r;
 #       endif
         } else { /* 32 bits */
 #       if defined(_MSC_VER)
             unsigned long r = 0;
             _BitScanReverse( &r, (unsigned long)val );
             return (unsigned)(r>>3);
 #       elif defined(__GNUC__) && (__GNUC__ >= 3)
             return (__builtin_clz((U32)val) >> 3);
 #       else
             unsigned r;
             if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
             r += (!val);
             return r;
 #       endif
     }   }
 }
 
 
 /*! ZDICT_count() :
     Count the nb of common bytes between 2 pointers.
     Note : this function presumes end of buffer followed by noisy guard band.
 */
 static size_t ZDICT_count(const void* pIn, const void* pMatch)
 {
     const char* const pStart = (const char*)pIn;
     for (;;) {
         size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn);
         if (!diff) {
             pIn = (const char*)pIn+sizeof(size_t);
             pMatch = (const char*)pMatch+sizeof(size_t);
             continue;
         }
         pIn = (const char*)pIn+ZDICT_NbCommonBytes(diff);
         return (size_t)((const char*)pIn - pStart);
     }
 }
 
 
 typedef struct {
     U32 pos;
     U32 length;
     U32 savings;
 } dictItem;
 
 static void ZDICT_initDictItem(dictItem* d)
 {
     d->pos = 1;
     d->length = 0;
     d->savings = (U32)(-1);
 }
 
 
 #define LLIMIT 64          /* heuristic determined experimentally */
 #define MINMATCHLENGTH 7   /* heuristic determined experimentally */
 static dictItem ZDICT_analyzePos(
                        BYTE* doneMarks,
                        const int* suffix, U32 start,
                        const void* buffer, U32 minRatio, U32 notificationLevel)
 {
     U32 lengthList[LLIMIT] = {0};
     U32 cumulLength[LLIMIT] = {0};
     U32 savings[LLIMIT] = {0};
     const BYTE* b = (const BYTE*)buffer;
     size_t length;
     size_t maxLength = LLIMIT;
     size_t pos = suffix[start];
     U32 end = start;
     dictItem solution;
 
     /* init */
     memset(&solution, 0, sizeof(solution));
     doneMarks[pos] = 1;
 
     /* trivial repetition cases */
     if ( (MEM_read16(b+pos+0) == MEM_read16(b+pos+2))
        ||(MEM_read16(b+pos+1) == MEM_read16(b+pos+3))
        ||(MEM_read16(b+pos+2) == MEM_read16(b+pos+4)) ) {
         /* skip and mark segment */
         U16 u16 = MEM_read16(b+pos+4);
         U32 u, e = 6;
         while (MEM_read16(b+pos+e) == u16) e+=2 ;
         if (b[pos+e] == b[pos+e-1]) e++;
         for (u=1; u=MINMATCHLENGTH);
 
     /* look backward */
     do {
         length = ZDICT_count(b + pos, b + *(suffix+start-1));
         if (length >=MINMATCHLENGTH) start--;
     } while(length >= MINMATCHLENGTH);
 
     /* exit if not found a minimum nb of repetitions */
     if (end-start < minRatio) {
         U32 idx;
         for(idx=start; idx= %i at pos %7u  ", (U32)(end-start), MINMATCHLENGTH, (U32)pos);
         DISPLAYLEVEL(4, "\n");
 
         for (searchLength = MINMATCHLENGTH ; ; searchLength++) {
             BYTE currentChar = 0;
             U32 currentCount = 0;
             U32 currentID = refinedStart;
             U32 id;
             U32 selectedCount = 0;
             U32 selectedID = currentID;
             for (id =refinedStart; id < refinedEnd; id++) {
                 if (b[ suffix[id] + searchLength] != currentChar) {
                     if (currentCount > selectedCount) {
                         selectedCount = currentCount;
                         selectedID = currentID;
                     }
                     currentID = id;
                     currentChar = b[ suffix[id] + searchLength];
                     currentCount = 0;
                 }
                 currentCount ++;
             }
             if (currentCount > selectedCount) {  /* for last */
                 selectedCount = currentCount;
                 selectedID = currentID;
             }
 
             if (selectedCount < minRatio)
                 break;
             refinedStart = selectedID;
             refinedEnd = refinedStart + selectedCount;
         }
 
         /* evaluate gain based on new ref */
         start = refinedStart;
         pos = suffix[refinedStart];
         end = start;
         memset(lengthList, 0, sizeof(lengthList));
 
         /* look forward */
         do {
             end++;
             length = ZDICT_count(b + pos, b + suffix[end]);
             if (length >= LLIMIT) length = LLIMIT-1;
             lengthList[length]++;
         } while (length >=MINMATCHLENGTH);
 
         /* look backward */
         length = MINMATCHLENGTH;
         while ((length >= MINMATCHLENGTH) & (start > 0)) {
             length = ZDICT_count(b + pos, b + suffix[start - 1]);
             if (length >= LLIMIT) length = LLIMIT - 1;
             lengthList[length]++;
             if (length >= MINMATCHLENGTH) start--;
         }
 
         /* largest useful length */
         memset(cumulLength, 0, sizeof(cumulLength));
         cumulLength[maxLength-1] = lengthList[maxLength-1];
         for (i=(int)(maxLength-2); i>=0; i--)
             cumulLength[i] = cumulLength[i+1] + lengthList[i];
 
         for (i=LLIMIT-1; i>=MINMATCHLENGTH; i--) if (cumulLength[i]>=minRatio) break;
         maxLength = i;
 
         /* reduce maxLength in case of final into repetitive data */
         {   U32 l = (U32)maxLength;
             BYTE const c = b[pos + maxLength-1];
             while (b[pos+l-2]==c) l--;
             maxLength = l;
         }
         if (maxLength < MINMATCHLENGTH) return solution;   /* skip : no long-enough solution */
 
         /* calculate savings */
         savings[5] = 0;
         for (i=MINMATCHLENGTH; i<=(int)maxLength; i++)
             savings[i] = savings[i-1] + (lengthList[i] * (i-3));
 
         DISPLAYLEVEL(4, "Selected ref at position %u, of length %u : saves %u (ratio: %.2f)  \n",
                      (U32)pos, (U32)maxLength, savings[maxLength], (double)savings[maxLength] / maxLength);
 
         solution.pos = (U32)pos;
         solution.length = (U32)maxLength;
         solution.savings = savings[maxLength];
 
         /* mark positions done */
         {   U32 id;
             for (id=start; id solution.length) length = solution.length;
                 }
                 pEnd = (U32)(testedPos + length);
                 for (p=testedPos; ppos;
     const U32 eltEnd = elt.pos + elt.length;
     const char* const buf = (const char*) buffer;
 
     /* tail overlap */
     U32 u; for (u=1; u elt.pos) && (table[u].pos <= eltEnd)) {  /* overlap, existing > new */
             /* append */
             U32 const addedLength = table[u].pos - elt.pos;
             table[u].length += addedLength;
             table[u].pos = elt.pos;
             table[u].savings += elt.savings * addedLength / elt.length;   /* rough approx */
             table[u].savings += elt.length / 8;    /* rough approx bonus */
             elt = table[u];
             /* sort : improve rank */
             while ((u>1) && (table[u-1].savings < elt.savings))
             table[u] = table[u-1], u--;
             table[u] = elt;
             return u;
     }   }
 
     /* front overlap */
     for (u=1; u= elt.pos) && (table[u].pos < elt.pos)) {  /* overlap, existing < new */
             /* append */
             int const addedLength = (int)eltEnd - (table[u].pos + table[u].length);
             table[u].savings += elt.length / 8;    /* rough approx bonus */
             if (addedLength > 0) {   /* otherwise, elt fully included into existing */
                 table[u].length += addedLength;
                 table[u].savings += elt.savings * addedLength / elt.length;   /* rough approx */
             }
             /* sort : improve rank */
             elt = table[u];
             while ((u>1) && (table[u-1].savings < elt.savings))
                 table[u] = table[u-1], u--;
             table[u] = elt;
             return u;
         }
 
         if (MEM_read64(buf + table[u].pos) == MEM_read64(buf + elt.pos + 1)) {
             if (isIncluded(buf + table[u].pos, buf + elt.pos + 1, table[u].length)) {
                 size_t const addedLength = MAX( (int)elt.length - (int)table[u].length , 1 );
                 table[u].pos = elt.pos;
                 table[u].savings += (U32)(elt.savings * addedLength / elt.length);
                 table[u].length = MIN(elt.length, table[u].length + 1);
                 return u;
             }
         }
     }
 
     return 0;
 }
 
 
 static void ZDICT_removeDictItem(dictItem* table, U32 id)
 {
     /* convention : table[0].pos stores nb of elts */
     U32 const max = table[0].pos;
     U32 u;
     if (!id) return;   /* protection, should never happen */
     for (u=id; upos--;
 }
 
 
 static void ZDICT_insertDictItem(dictItem* table, U32 maxSize, dictItem elt, const void* buffer)
 {
     /* merge if possible */
     U32 mergeId = ZDICT_tryMerge(table, elt, 0, buffer);
     if (mergeId) {
         U32 newMerge = 1;
         while (newMerge) {
             newMerge = ZDICT_tryMerge(table, table[mergeId], mergeId, buffer);
             if (newMerge) ZDICT_removeDictItem(table, mergeId);
             mergeId = newMerge;
         }
         return;
     }
 
     /* insert */
     {   U32 current;
         U32 nextElt = table->pos;
         if (nextElt >= maxSize) nextElt = maxSize-1;
         current = nextElt-1;
         while (table[current].savings < elt.savings) {
             table[current+1] = table[current];
             current--;
         }
         table[current+1] = elt;
         table->pos = nextElt+1;
     }
 }
 
 
 static U32 ZDICT_dictSize(const dictItem* dictList)
 {
     U32 u, dictSize = 0;
     for (u=1; u=l) { \
             if (ZDICT_clockSpan(displayClock) > refreshRate)  \
             { displayClock = clock(); DISPLAY(__VA_ARGS__); \
             if (notificationLevel>=4) fflush(stderr); } }
 
     /* init */
     DISPLAYLEVEL(2, "\r%70s\r", "");   /* clean display line */
     if (!suffix0 || !reverseSuffix || !doneMarks || !filePos) {
         result = ERROR(memory_allocation);
         goto _cleanup;
     }
     if (minRatio < MINRATIO) minRatio = MINRATIO;
     memset(doneMarks, 0, bufferSize+16);
 
     /* limit sample set size (divsufsort limitation)*/
     if (bufferSize > ZDICT_MAX_SAMPLES_SIZE) DISPLAYLEVEL(3, "sample set too large : reduced to %u MB ...\n", (U32)(ZDICT_MAX_SAMPLES_SIZE>>20));
     while (bufferSize > ZDICT_MAX_SAMPLES_SIZE) bufferSize -= fileSizes[--nbFiles];
 
     /* sort */
     DISPLAYLEVEL(2, "sorting %u files of total size %u MB ...\n", nbFiles, (U32)(bufferSize>>20));
     {   int const divSuftSortResult = divsufsort((const unsigned char*)buffer, suffix, (int)bufferSize, 0);
         if (divSuftSortResult != 0) { result = ERROR(GENERIC); goto _cleanup; }
     }
     suffix[bufferSize] = (int)bufferSize;   /* leads into noise */
     suffix0[0] = (int)bufferSize;           /* leads into noise */
     /* build reverse suffix sort */
     {   size_t pos;
         for (pos=0; pos < bufferSize; pos++)
             reverseSuffix[suffix[pos]] = (U32)pos;
         /* note filePos tracks borders between samples.
            It's not used at this stage, but planned to become useful in a later update */
         filePos[0] = 0;
         for (pos=1; pos> 21);
     }
 }
 
 
 typedef struct
 {
     ZSTD_CCtx* ref;
     ZSTD_CCtx* zc;
     void* workPlace;   /* must be ZSTD_BLOCKSIZE_MAX allocated */
 } EStats_ress_t;
 
 #define MAXREPOFFSET 1024
 
 static void ZDICT_countEStats(EStats_ress_t esr, ZSTD_parameters params,
                             U32* countLit, U32* offsetcodeCount, U32* matchlengthCount, U32* litlengthCount, U32* repOffsets,
                             const void* src, size_t srcSize, U32 notificationLevel)
 {
     size_t const blockSizeMax = MIN (ZSTD_BLOCKSIZE_MAX, 1 << params.cParams.windowLog);
     size_t cSize;
 
     if (srcSize > blockSizeMax) srcSize = blockSizeMax;   /* protection vs large samples */
     {  size_t const errorCode = ZSTD_copyCCtx(esr.zc, esr.ref, 0);
             if (ZSTD_isError(errorCode)) { DISPLAYLEVEL(1, "warning : ZSTD_copyCCtx failed \n"); return; }
     }
     cSize = ZSTD_compressBlock(esr.zc, esr.workPlace, ZSTD_BLOCKSIZE_MAX, src, srcSize);
     if (ZSTD_isError(cSize)) { DISPLAYLEVEL(3, "warning : could not compress sample size %u \n", (U32)srcSize); return; }
 
     if (cSize) {  /* if == 0; block is not compressible */
         const seqStore_t* seqStorePtr = ZSTD_getSeqStore(esr.zc);
 
         /* literals stats */
         {   const BYTE* bytePtr;
             for(bytePtr = seqStorePtr->litStart; bytePtr < seqStorePtr->lit; bytePtr++)
                 countLit[*bytePtr]++;
         }
 
         /* seqStats */
         {   U32 const nbSeq = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
             ZSTD_seqToCodes(seqStorePtr);
 
             {   const BYTE* codePtr = seqStorePtr->ofCode;
                 U32 u;
                 for (u=0; umlCode;
                 U32 u;
                 for (u=0; ullCode;
                 U32 u;
                 for (u=0; u= 2) { /* rep offsets */
                 const seqDef* const seq = seqStorePtr->sequencesStart;
                 U32 offset1 = seq[0].offset - 3;
                 U32 offset2 = seq[1].offset - 3;
                 if (offset1 >= MAXREPOFFSET) offset1 = 0;
                 if (offset2 >= MAXREPOFFSET) offset2 = 0;
                 repOffsets[offset1] += 3;
                 repOffsets[offset2] += 1;
     }   }   }
 }
 
 static size_t ZDICT_totalSampleSize(const size_t* fileSizes, unsigned nbFiles)
 {
     size_t total=0;
     unsigned u;
     for (u=0; u0; u--) {
         offsetCount_t tmp;
         if (table[u-1].count >= table[u].count) break;
         tmp = table[u-1];
         table[u-1] = table[u];
         table[u] = tmp;
     }
 }
 
 
 #define OFFCODE_MAX 30  /* only applicable to first block */
 static size_t ZDICT_analyzeEntropy(void*  dstBuffer, size_t maxDstSize,
                                    unsigned compressionLevel,
                              const void*  srcBuffer, const size_t* fileSizes, unsigned nbFiles,
                              const void* dictBuffer, size_t  dictBufferSize,
                                    unsigned notificationLevel)
 {
     U32 countLit[256];
     HUF_CREATE_STATIC_CTABLE(hufTable, 255);
     U32 offcodeCount[OFFCODE_MAX+1];
     short offcodeNCount[OFFCODE_MAX+1];
     U32 offcodeMax = ZSTD_highbit32((U32)(dictBufferSize + 128 KB));
     U32 matchLengthCount[MaxML+1];
     short matchLengthNCount[MaxML+1];
     U32 litLengthCount[MaxLL+1];
     short litLengthNCount[MaxLL+1];
     U32 repOffset[MAXREPOFFSET];
     offsetCount_t bestRepOffset[ZSTD_REP_NUM+1];
     EStats_ress_t esr;
     ZSTD_parameters params;
     U32 u, huffLog = 11, Offlog = OffFSELog, mlLog = MLFSELog, llLog = LLFSELog, total;
     size_t pos = 0, errorCode;
     size_t eSize = 0;
     size_t const totalSrcSize = ZDICT_totalSampleSize(fileSizes, nbFiles);
     size_t const averageSampleSize = totalSrcSize / (nbFiles + !nbFiles);
     BYTE* dstPtr = (BYTE*)dstBuffer;
 
     /* init */
     esr.ref = ZSTD_createCCtx();
     esr.zc = ZSTD_createCCtx();
     esr.workPlace = malloc(ZSTD_BLOCKSIZE_MAX);
     if (!esr.ref || !esr.zc || !esr.workPlace) {
         eSize = ERROR(memory_allocation);
         DISPLAYLEVEL(1, "Not enough memory \n");
         goto _cleanup;
     }
     if (offcodeMax>OFFCODE_MAX) { eSize = ERROR(dictionaryCreation_failed); goto _cleanup; }   /* too large dictionary */
     for (u=0; u<256; u++) countLit[u] = 1;   /* any character must be described */
     for (u=0; u<=offcodeMax; u++) offcodeCount[u] = 1;
     for (u=0; u<=MaxML; u++) matchLengthCount[u] = 1;
     for (u=0; u<=MaxLL; u++) litLengthCount[u] = 1;
     memset(repOffset, 0, sizeof(repOffset));
     repOffset[1] = repOffset[4] = repOffset[8] = 1;
     memset(bestRepOffset, 0, sizeof(bestRepOffset));
     if (compressionLevel<=0) compressionLevel = g_compressionLevel_default;
     params = ZSTD_getParams(compressionLevel, averageSampleSize, dictBufferSize);
     {   size_t const beginResult = ZSTD_compressBegin_advanced(esr.ref, dictBuffer, dictBufferSize, params, 0);
         if (ZSTD_isError(beginResult)) {
             DISPLAYLEVEL(1, "error : ZSTD_compressBegin_advanced() failed : %s \n", ZSTD_getErrorName(beginResult));
             eSize = ERROR(GENERIC);
             goto _cleanup;
     }   }
 
     /* collect stats on all files */
     for (u=0; u dictBufferCapacity) dictContentSize = dictBufferCapacity - hSize;
     {   size_t const dictSize = hSize + dictContentSize;
         char* dictEnd = (char*)dictBuffer + dictSize;
         memmove(dictEnd - dictContentSize, customDictContent, dictContentSize);
         memcpy(dictBuffer, header, hSize);
         return dictSize;
     }
 }
 
 
 size_t ZDICT_addEntropyTablesFromBuffer_advanced(void* dictBuffer, size_t dictContentSize, size_t dictBufferCapacity,
                                                  const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
                                                  ZDICT_params_t params)
 {
     int const compressionLevel = (params.compressionLevel <= 0) ? g_compressionLevel_default : params.compressionLevel;
     U32 const notificationLevel = params.notificationLevel;
     size_t hSize = 8;
 
     /* calculate entropy tables */
     DISPLAYLEVEL(2, "\r%70s\r", "");   /* clean display line */
     DISPLAYLEVEL(2, "statistics ... \n");
     {   size_t const eSize = ZDICT_analyzeEntropy((char*)dictBuffer+hSize, dictBufferCapacity-hSize,
                                   compressionLevel,
                                   samplesBuffer, samplesSizes, nbSamples,
                                   (char*)dictBuffer + dictBufferCapacity - dictContentSize, dictContentSize,
                                   notificationLevel);
         if (ZDICT_isError(eSize)) return eSize;
         hSize += eSize;
     }
 
     /* add dictionary header (after entropy tables) */
     MEM_writeLE32(dictBuffer, ZSTD_MAGIC_DICTIONARY);
     {   U64 const randomID = XXH64((char*)dictBuffer + dictBufferCapacity - dictContentSize, dictContentSize, 0);
         U32 const compliantID = (randomID % ((1U<<31)-32768)) + 32768;
         U32 const dictID = params.dictID ? params.dictID : compliantID;
         MEM_writeLE32((char*)dictBuffer+4, dictID);
     }
 
     if (hSize + dictContentSize < dictBufferCapacity)
         memmove((char*)dictBuffer + hSize, (char*)dictBuffer + dictBufferCapacity - dictContentSize, dictContentSize);
     return MIN(dictBufferCapacity, hSize+dictContentSize);
 }
 
 
 /*! ZDICT_trainFromBuffer_unsafe_legacy() :
 *   Warning : `samplesBuffer` must be followed by noisy guard band.
 *   @return : size of dictionary, or an error code which can be tested with ZDICT_isError()
 */
 size_t ZDICT_trainFromBuffer_unsafe_legacy(
                             void* dictBuffer, size_t maxDictSize,
                             const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
                             ZDICT_legacy_params_t params)
 {
     U32 const dictListSize = MAX(MAX(DICTLISTSIZE_DEFAULT, nbSamples), (U32)(maxDictSize/16));
     dictItem* const dictList = (dictItem*)malloc(dictListSize * sizeof(*dictList));
     unsigned const selectivity = params.selectivityLevel == 0 ? g_selectivity_default : params.selectivityLevel;
     unsigned const minRep = (selectivity > 30) ? MINRATIO : nbSamples >> selectivity;
     size_t const targetDictSize = maxDictSize;
     size_t const samplesBuffSize = ZDICT_totalSampleSize(samplesSizes, nbSamples);
     size_t dictSize = 0;
     U32 const notificationLevel = params.zParams.notificationLevel;
 
     /* checks */
     if (!dictList) return ERROR(memory_allocation);
     if (maxDictSize < ZDICT_DICTSIZE_MIN) { free(dictList); return ERROR(dstSize_tooSmall); }   /* requested dictionary size is too small */
     if (samplesBuffSize < ZDICT_MIN_SAMPLES_SIZE) { free(dictList); return ERROR(dictionaryCreation_failed); }   /* not enough source to create dictionary */
 
     /* init */
     ZDICT_initDictItem(dictList);
 
     /* build dictionary */
     ZDICT_trainBuffer_legacy(dictList, dictListSize,
                        samplesBuffer, samplesBuffSize,
                        samplesSizes, nbSamples,
                        minRep, notificationLevel);
 
     /* display best matches */
     if (params.zParams.notificationLevel>= 3) {
         U32 const nb = MIN(25, dictList[0].pos);
         U32 const dictContentSize = ZDICT_dictSize(dictList);
         U32 u;
         DISPLAYLEVEL(3, "\n %u segments found, of total size %u \n", dictList[0].pos-1, dictContentSize);
         DISPLAYLEVEL(3, "list %u best segments \n", nb-1);
         for (u=1; u samplesBuffSize) || ((pos + length) > samplesBuffSize))
                 return ERROR(GENERIC);   /* should never happen */
             DISPLAYLEVEL(3, "%3u:%3u bytes at pos %8u, savings %7u bytes |",
                          u, length, pos, dictList[u].savings);
             ZDICT_printHex((const char*)samplesBuffer+pos, printedLength);
             DISPLAYLEVEL(3, "| \n");
     }   }
 
 
     /* create dictionary */
     {   U32 dictContentSize = ZDICT_dictSize(dictList);
         if (dictContentSize < ZDICT_CONTENTSIZE_MIN) { free(dictList); return ERROR(dictionaryCreation_failed); }   /* dictionary content too small */
         if (dictContentSize < targetDictSize/4) {
             DISPLAYLEVEL(2, "!  warning : selected content significantly smaller than requested (%u < %u) \n", dictContentSize, (U32)maxDictSize);
             if (samplesBuffSize < 10 * targetDictSize)
                 DISPLAYLEVEL(2, "!  consider increasing the number of samples (total size : %u MB)\n", (U32)(samplesBuffSize>>20));
             if (minRep > MINRATIO) {
                 DISPLAYLEVEL(2, "!  consider increasing selectivity to produce larger dictionary (-s%u) \n", selectivity+1);
                 DISPLAYLEVEL(2, "!  note : larger dictionaries are not necessarily better, test its efficiency on samples \n");
             }
         }
 
         if ((dictContentSize > targetDictSize*3) && (nbSamples > 2*MINRATIO) && (selectivity>1)) {
             U32 proposedSelectivity = selectivity-1;
             while ((nbSamples >> proposedSelectivity) <= MINRATIO) { proposedSelectivity--; }
             DISPLAYLEVEL(2, "!  note : calculated dictionary significantly larger than requested (%u > %u) \n", dictContentSize, (U32)maxDictSize);
             DISPLAYLEVEL(2, "!  consider increasing dictionary size, or produce denser dictionary (-s%u) \n", proposedSelectivity);
             DISPLAYLEVEL(2, "!  always test dictionary efficiency on real samples \n");
         }
 
         /* limit dictionary size */
         {   U32 const max = dictList->pos;   /* convention : nb of useful elts within dictList */
             U32 currentSize = 0;
             U32 n; for (n=1; n targetDictSize) { currentSize -= dictList[n].length; break; }
             }
             dictList->pos = n;
             dictContentSize = currentSize;
         }
 
         /* build dict content */
         {   U32 u;
             BYTE* ptr = (BYTE*)dictBuffer + maxDictSize;
             for (u=1; upos; u++) {
                 U32 l = dictList[u].length;
                 ptr -= l;
                 if (ptr<(BYTE*)dictBuffer) { free(dictList); return ERROR(GENERIC); }   /* should not happen */
                 memcpy(ptr, (const char*)samplesBuffer+dictList[u].pos, l);
         }   }
 
         dictSize = ZDICT_addEntropyTablesFromBuffer_advanced(dictBuffer, dictContentSize, maxDictSize,
                                                              samplesBuffer, samplesSizes, nbSamples,
                                                              params.zParams);
     }
 
     /* clean up */
     free(dictList);
     return dictSize;
 }
 
 
 /* issue : samplesBuffer need to be followed by a noisy guard band.
 *  work around : duplicate the buffer, and add the noise */
 size_t ZDICT_trainFromBuffer_legacy(void* dictBuffer, size_t dictBufferCapacity,
                               const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
                               ZDICT_legacy_params_t params)
 {
     size_t result;
     void* newBuff;
     size_t const sBuffSize = ZDICT_totalSampleSize(samplesSizes, nbSamples);
     if (sBuffSize < ZDICT_MIN_SAMPLES_SIZE) return 0;   /* not enough content => no dictionary */
 
     newBuff = malloc(sBuffSize + NOISELENGTH);
     if (!newBuff) return ERROR(memory_allocation);
 
     memcpy(newBuff, samplesBuffer, sBuffSize);
     ZDICT_fillNoise((char*)newBuff + sBuffSize, NOISELENGTH);   /* guard band, for end of buffer condition */
 
     result =
         ZDICT_trainFromBuffer_unsafe_legacy(dictBuffer, dictBufferCapacity, newBuff,
                                             samplesSizes, nbSamples, params);
     free(newBuff);
     return result;
 }
 
 
 size_t ZDICT_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
                              const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples)
 {
     ZDICT_cover_params_t params;
     memset(¶ms, 0, sizeof(params));
     params.d = 8;
     params.steps = 4;
     /* Default to level 6 since no compression level information is avaialble */
     params.zParams.compressionLevel = 6;
     return ZDICT_optimizeTrainFromBuffer_cover(dictBuffer, dictBufferCapacity,
                                                samplesBuffer, samplesSizes,
                                                nbSamples, ¶ms);
 }
 
 size_t ZDICT_addEntropyTablesFromBuffer(void* dictBuffer, size_t dictContentSize, size_t dictBufferCapacity,
                                         const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples)
 {
     ZDICT_params_t params;
     memset(¶ms, 0, sizeof(params));
     return ZDICT_addEntropyTablesFromBuffer_advanced(dictBuffer, dictContentSize, dictBufferCapacity,
                                                      samplesBuffer, samplesSizes, nbSamples,
                                                      params);
 }
Index: head/sys/contrib/zstd/lib/legacy/zstd_v01.c
===================================================================
--- head/sys/contrib/zstd/lib/legacy/zstd_v01.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/legacy/zstd_v01.c	(revision 330894)
@@ -1,2127 +1,2127 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 
 /******************************************
 *  Includes
 ******************************************/
 #include     /* size_t, ptrdiff_t */
 #include "zstd_v01.h"
 #include "error_private.h"
 
 
 /******************************************
 *  Static allocation
 ******************************************/
 /* You can statically allocate FSE CTable/DTable as a table of unsigned using below macro */
 #define FSE_DTABLE_SIZE_U32(maxTableLog)                   (1 + (1<2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
 *  Increasing memory usage improves compression ratio
 *  Reduced memory usage can improve speed, due to cache effect
 *  Recommended max value is 14, for 16KB, which nicely fits into Intel x86 L1 cache */
 #define FSE_MAX_MEMORY_USAGE 14
 #define FSE_DEFAULT_MEMORY_USAGE 13
 
 /* FSE_MAX_SYMBOL_VALUE :
 *  Maximum symbol value authorized.
 *  Required for proper stack allocation */
 #define FSE_MAX_SYMBOL_VALUE 255
 
 
 /****************************************************************
 *  template functions type & suffix
 ****************************************************************/
 #define FSE_FUNCTION_TYPE BYTE
 #define FSE_FUNCTION_EXTENSION
 
 
 /****************************************************************
 *  Byte symbol type
 ****************************************************************/
 typedef struct
 {
     unsigned short newState;
     unsigned char  symbol;
     unsigned char  nbBits;
 } FSE_decode_t;   /* size == U32 */
 
 
 
 /****************************************************************
 *  Compiler specifics
 ****************************************************************/
 #ifdef _MSC_VER    /* Visual Studio */
 #  define FORCE_INLINE static __forceinline
 #  include                     /* For Visual 2005 */
 #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
 #  pragma warning(disable : 4214)        /* disable: C4214: non-int bitfields */
 #else
 #  define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
 #  if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
 #    ifdef __GNUC__
 #      define FORCE_INLINE static inline __attribute__((always_inline))
 #    else
 #      define FORCE_INLINE static inline
 #    endif
 #  else
 #    define FORCE_INLINE static
 #  endif /* __STDC_VERSION__ */
 #endif
 
 
 /****************************************************************
 *  Includes
 ****************************************************************/
 #include      /* malloc, free, qsort */
 #include      /* memcpy, memset */
 #include       /* printf (debug) */
 
 
 #ifndef MEM_ACCESS_MODULE
 #define MEM_ACCESS_MODULE
 /****************************************************************
 *  Basic Types
 *****************************************************************/
 #if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
 # include 
 typedef  uint8_t BYTE;
 typedef uint16_t U16;
 typedef  int16_t S16;
 typedef uint32_t U32;
 typedef  int32_t S32;
 typedef uint64_t U64;
 typedef  int64_t S64;
 #else
 typedef unsigned char       BYTE;
 typedef unsigned short      U16;
 typedef   signed short      S16;
 typedef unsigned int        U32;
 typedef   signed int        S32;
 typedef unsigned long long  U64;
 typedef   signed long long  S64;
 #endif
 
 #endif   /* MEM_ACCESS_MODULE */
 
 /****************************************************************
 *  Memory I/O
 *****************************************************************/
 /* FSE_FORCE_MEMORY_ACCESS
  * By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable.
  * Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal.
  * The below switch allow to select different access method for improved performance.
  * Method 0 (default) : use `memcpy()`. Safe and portable.
  * Method 1 : `__packed` statement. It depends on compiler extension (ie, not portable).
  *            This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`.
  * Method 2 : direct access. This method is portable but violate C standard.
  *            It can generate buggy code on targets generating assembly depending on alignment.
  *            But in some circumstances, it's the only known way to get the most performance (ie GCC + ARMv6)
  * See http://fastcompression.blogspot.fr/2015/08/accessing-unaligned-memory.html for details.
  * Prefer these methods in priority order (0 > 1 > 2)
  */
 #ifndef FSE_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
 #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
 #    define FSE_FORCE_MEMORY_ACCESS 2
 #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) ))
 #    define FSE_FORCE_MEMORY_ACCESS 1
 #  endif
 #endif
 
 
 static unsigned FSE_32bits(void)
 {
     return sizeof(void*)==4;
 }
 
 static unsigned FSE_isLittleEndian(void)
 {
     const union { U32 i; BYTE c[4]; } one = { 1 };   /* don't use static : performance detrimental  */
     return one.c[0];
 }
 
 #if defined(FSE_FORCE_MEMORY_ACCESS) && (FSE_FORCE_MEMORY_ACCESS==2)
 
 static U16 FSE_read16(const void* memPtr) { return *(const U16*) memPtr; }
 static U32 FSE_read32(const void* memPtr) { return *(const U32*) memPtr; }
 static U64 FSE_read64(const void* memPtr) { return *(const U64*) memPtr; }
 
 #elif defined(FSE_FORCE_MEMORY_ACCESS) && (FSE_FORCE_MEMORY_ACCESS==1)
 
 /* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
 /* currently only defined for gcc and icc */
 typedef union { U16 u16; U32 u32; U64 u64; } __attribute__((packed)) unalign;
 
 static U16 FSE_read16(const void* ptr) { return ((const unalign*)ptr)->u16; }
 static U32 FSE_read32(const void* ptr) { return ((const unalign*)ptr)->u32; }
 static U64 FSE_read64(const void* ptr) { return ((const unalign*)ptr)->u64; }
 
 #else
 
 static U16 FSE_read16(const void* memPtr)
 {
     U16 val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
 static U32 FSE_read32(const void* memPtr)
 {
     U32 val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
 static U64 FSE_read64(const void* memPtr)
 {
     U64 val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
 #endif // FSE_FORCE_MEMORY_ACCESS
 
 static U16 FSE_readLE16(const void* memPtr)
 {
     if (FSE_isLittleEndian())
         return FSE_read16(memPtr);
     else
     {
         const BYTE* p = (const BYTE*)memPtr;
         return (U16)(p[0] + (p[1]<<8));
     }
 }
 
 static U32 FSE_readLE32(const void* memPtr)
 {
     if (FSE_isLittleEndian())
         return FSE_read32(memPtr);
     else
     {
         const BYTE* p = (const BYTE*)memPtr;
         return (U32)((U32)p[0] + ((U32)p[1]<<8) + ((U32)p[2]<<16) + ((U32)p[3]<<24));
     }
 }
 
 
 static U64 FSE_readLE64(const void* memPtr)
 {
     if (FSE_isLittleEndian())
         return FSE_read64(memPtr);
     else
     {
         const BYTE* p = (const BYTE*)memPtr;
         return (U64)((U64)p[0] + ((U64)p[1]<<8) + ((U64)p[2]<<16) + ((U64)p[3]<<24)
                      + ((U64)p[4]<<32) + ((U64)p[5]<<40) + ((U64)p[6]<<48) + ((U64)p[7]<<56));
     }
 }
 
 static size_t FSE_readLEST(const void* memPtr)
 {
     if (FSE_32bits())
         return (size_t)FSE_readLE32(memPtr);
     else
         return (size_t)FSE_readLE64(memPtr);
 }
 
 
 
 /****************************************************************
 *  Constants
 *****************************************************************/
 #define FSE_MAX_TABLELOG  (FSE_MAX_MEMORY_USAGE-2)
 #define FSE_MAX_TABLESIZE (1U< FSE_TABLELOG_ABSOLUTE_MAX
 #error "FSE_MAX_TABLELOG > FSE_TABLELOG_ABSOLUTE_MAX is not supported"
 #endif
 
 
 /****************************************************************
 *  Error Management
 ****************************************************************/
 #define FSE_STATIC_ASSERT(c) { enum { FSE_static_assert = 1/(int)(!!(c)) }; }   /* use only *after* variable declarations */
 
 
 /****************************************************************
 *  Complex types
 ****************************************************************/
 typedef struct
 {
     int deltaFindState;
     U32 deltaNbBits;
 } FSE_symbolCompressionTransform; /* total 8 bytes */
 
 typedef U32 DTable_max_t[FSE_DTABLE_SIZE_U32(FSE_MAX_TABLELOG)];
 
 /****************************************************************
 *  Internal functions
 ****************************************************************/
-FORCE_INLINE unsigned FSE_highbit32 (register U32 val)
+FORCE_INLINE unsigned FSE_highbit32 (U32 val)
 {
 #   if defined(_MSC_VER)   /* Visual */
     unsigned long r;
     _BitScanReverse ( &r, val );
     return (unsigned) r;
 #   elif defined(__GNUC__) && (GCC_VERSION >= 304)   /* GCC Intrinsic */
     return 31 - __builtin_clz (val);
 #   else   /* Software version */
     static const unsigned DeBruijnClz[32] = { 0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30, 8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31 };
     U32 v = val;
     unsigned r;
     v |= v >> 1;
     v |= v >> 2;
     v |= v >> 4;
     v |= v >> 8;
     v |= v >> 16;
     r = DeBruijnClz[ (U32) (v * 0x07C4ACDDU) >> 27];
     return r;
 #   endif
 }
 
 
 /****************************************************************
 *  Templates
 ****************************************************************/
 /*
   designed to be included
   for type-specific functions (template emulation in C)
   Objective is to write these functions only once, for improved maintenance
 */
 
 /* safety checks */
 #ifndef FSE_FUNCTION_EXTENSION
 #  error "FSE_FUNCTION_EXTENSION must be defined"
 #endif
 #ifndef FSE_FUNCTION_TYPE
 #  error "FSE_FUNCTION_TYPE must be defined"
 #endif
 
 /* Function names */
 #define FSE_CAT(X,Y) X##Y
 #define FSE_FUNCTION_NAME(X,Y) FSE_CAT(X,Y)
 #define FSE_TYPE_NAME(X,Y) FSE_CAT(X,Y)
 
 
 
 static U32 FSE_tableStep(U32 tableSize) { return (tableSize>>1) + (tableSize>>3) + 3; }
 
 #define FSE_DECODE_TYPE FSE_decode_t
 
 
 typedef struct {
     U16 tableLog;
     U16 fastMode;
 } FSE_DTableHeader;   /* sizeof U32 */
 
 static size_t FSE_buildDTable
 (FSE_DTable* dt, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog)
 {
     void* ptr = dt;
     FSE_DTableHeader* const DTableH = (FSE_DTableHeader*)ptr;
     FSE_DECODE_TYPE* const tableDecode = (FSE_DECODE_TYPE*)(ptr) + 1;   /* because dt is unsigned, 32-bits aligned on 32-bits */
     const U32 tableSize = 1 << tableLog;
     const U32 tableMask = tableSize-1;
     const U32 step = FSE_tableStep(tableSize);
     U16 symbolNext[FSE_MAX_SYMBOL_VALUE+1];
     U32 position = 0;
     U32 highThreshold = tableSize-1;
     const S16 largeLimit= (S16)(1 << (tableLog-1));
     U32 noLarge = 1;
     U32 s;
 
     /* Sanity Checks */
     if (maxSymbolValue > FSE_MAX_SYMBOL_VALUE) return (size_t)-FSE_ERROR_maxSymbolValue_tooLarge;
     if (tableLog > FSE_MAX_TABLELOG) return (size_t)-FSE_ERROR_tableLog_tooLarge;
 
     /* Init, lay down lowprob symbols */
     DTableH[0].tableLog = (U16)tableLog;
     for (s=0; s<=maxSymbolValue; s++)
     {
         if (normalizedCounter[s]==-1)
         {
             tableDecode[highThreshold--].symbol = (FSE_FUNCTION_TYPE)s;
             symbolNext[s] = 1;
         }
         else
         {
             if (normalizedCounter[s] >= largeLimit) noLarge=0;
             symbolNext[s] = normalizedCounter[s];
         }
     }
 
     /* Spread symbols */
     for (s=0; s<=maxSymbolValue; s++)
     {
         int i;
         for (i=0; i highThreshold) position = (position + step) & tableMask;   /* lowprob area */
         }
     }
 
     if (position!=0) return (size_t)-FSE_ERROR_GENERIC;   /* position must reach all cells once, otherwise normalizedCounter is incorrect */
 
     /* Build Decoding table */
     {
         U32 i;
         for (i=0; ifastMode = (U16)noLarge;
     return 0;
 }
 
 
 /******************************************
 *  FSE byte symbol
 ******************************************/
 #ifndef FSE_COMMONDEFS_ONLY
 
 static unsigned FSE_isError(size_t code) { return (code > (size_t)(-FSE_ERROR_maxCode)); }
 
 static short FSE_abs(short a)
 {
     return a<0? -a : a;
 }
 
 
 /****************************************************************
 *  Header bitstream management
 ****************************************************************/
 static size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
                  const void* headerBuffer, size_t hbSize)
 {
     const BYTE* const istart = (const BYTE*) headerBuffer;
     const BYTE* const iend = istart + hbSize;
     const BYTE* ip = istart;
     int nbBits;
     int remaining;
     int threshold;
     U32 bitStream;
     int bitCount;
     unsigned charnum = 0;
     int previous0 = 0;
 
     if (hbSize < 4) return (size_t)-FSE_ERROR_srcSize_wrong;
     bitStream = FSE_readLE32(ip);
     nbBits = (bitStream & 0xF) + FSE_MIN_TABLELOG;   /* extract tableLog */
     if (nbBits > FSE_TABLELOG_ABSOLUTE_MAX) return (size_t)-FSE_ERROR_tableLog_tooLarge;
     bitStream >>= 4;
     bitCount = 4;
     *tableLogPtr = nbBits;
     remaining = (1<1) && (charnum<=*maxSVPtr))
     {
         if (previous0)
         {
             unsigned n0 = charnum;
             while ((bitStream & 0xFFFF) == 0xFFFF)
             {
                 n0+=24;
                 if (ip < iend-5)
                 {
                     ip+=2;
                     bitStream = FSE_readLE32(ip) >> bitCount;
                 }
                 else
                 {
                     bitStream >>= 16;
                     bitCount+=16;
                 }
             }
             while ((bitStream & 3) == 3)
             {
                 n0+=3;
                 bitStream>>=2;
                 bitCount+=2;
             }
             n0 += bitStream & 3;
             bitCount += 2;
             if (n0 > *maxSVPtr) return (size_t)-FSE_ERROR_maxSymbolValue_tooSmall;
             while (charnum < n0) normalizedCounter[charnum++] = 0;
             if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4))
             {
                 ip += bitCount>>3;
                 bitCount &= 7;
                 bitStream = FSE_readLE32(ip) >> bitCount;
             }
             else
                 bitStream >>= 2;
         }
         {
             const short max = (short)((2*threshold-1)-remaining);
             short count;
 
             if ((bitStream & (threshold-1)) < (U32)max)
             {
                 count = (short)(bitStream & (threshold-1));
                 bitCount   += nbBits-1;
             }
             else
             {
                 count = (short)(bitStream & (2*threshold-1));
                 if (count >= threshold) count -= max;
                 bitCount   += nbBits;
             }
 
             count--;   /* extra accuracy */
             remaining -= FSE_abs(count);
             normalizedCounter[charnum++] = count;
             previous0 = !count;
             while (remaining < threshold)
             {
                 nbBits--;
                 threshold >>= 1;
             }
 
             {
                 if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4))
                 {
                     ip += bitCount>>3;
                     bitCount &= 7;
                 }
                 else
                 {
                     bitCount -= (int)(8 * (iend - 4 - ip));
                     ip = iend - 4;
                 }
                 bitStream = FSE_readLE32(ip) >> (bitCount & 31);
             }
         }
     }
     if (remaining != 1) return (size_t)-FSE_ERROR_GENERIC;
     *maxSVPtr = charnum-1;
 
     ip += (bitCount+7)>>3;
     if ((size_t)(ip-istart) > hbSize) return (size_t)-FSE_ERROR_srcSize_wrong;
     return ip-istart;
 }
 
 
 /*********************************************************
 *  Decompression (Byte symbols)
 *********************************************************/
 static size_t FSE_buildDTable_rle (FSE_DTable* dt, BYTE symbolValue)
 {
     void* ptr = dt;
     FSE_DTableHeader* const DTableH = (FSE_DTableHeader*)ptr;
     FSE_decode_t* const cell = (FSE_decode_t*)(ptr) + 1;   /* because dt is unsigned */
 
     DTableH->tableLog = 0;
     DTableH->fastMode = 0;
 
     cell->newState = 0;
     cell->symbol = symbolValue;
     cell->nbBits = 0;
 
     return 0;
 }
 
 
 static size_t FSE_buildDTable_raw (FSE_DTable* dt, unsigned nbBits)
 {
     void* ptr = dt;
     FSE_DTableHeader* const DTableH = (FSE_DTableHeader*)ptr;
     FSE_decode_t* const dinfo = (FSE_decode_t*)(ptr) + 1;   /* because dt is unsigned */
     const unsigned tableSize = 1 << nbBits;
     const unsigned tableMask = tableSize - 1;
     const unsigned maxSymbolValue = tableMask;
     unsigned s;
 
     /* Sanity checks */
     if (nbBits < 1) return (size_t)-FSE_ERROR_GENERIC;             /* min size */
 
     /* Build Decoding Table */
     DTableH->tableLog = (U16)nbBits;
     DTableH->fastMode = 1;
     for (s=0; s<=maxSymbolValue; s++)
     {
         dinfo[s].newState = 0;
         dinfo[s].symbol = (BYTE)s;
         dinfo[s].nbBits = (BYTE)nbBits;
     }
 
     return 0;
 }
 
 
 /* FSE_initDStream
  * Initialize a FSE_DStream_t.
  * srcBuffer must point at the beginning of an FSE block.
  * The function result is the size of the FSE_block (== srcSize).
  * If srcSize is too small, the function will return an errorCode;
  */
 static size_t FSE_initDStream(FSE_DStream_t* bitD, const void* srcBuffer, size_t srcSize)
 {
     if (srcSize < 1) return (size_t)-FSE_ERROR_srcSize_wrong;
 
     if (srcSize >=  sizeof(size_t))
     {
         U32 contain32;
         bitD->start = (const char*)srcBuffer;
         bitD->ptr   = (const char*)srcBuffer + srcSize - sizeof(size_t);
         bitD->bitContainer = FSE_readLEST(bitD->ptr);
         contain32 = ((const BYTE*)srcBuffer)[srcSize-1];
         if (contain32 == 0) return (size_t)-FSE_ERROR_GENERIC;   /* stop bit not present */
         bitD->bitsConsumed = 8 - FSE_highbit32(contain32);
     }
     else
     {
         U32 contain32;
         bitD->start = (const char*)srcBuffer;
         bitD->ptr   = bitD->start;
         bitD->bitContainer = *(const BYTE*)(bitD->start);
         switch(srcSize)
         {
             case 7: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[6]) << (sizeof(size_t)*8 - 16);
             case 6: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[5]) << (sizeof(size_t)*8 - 24);
             case 5: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[4]) << (sizeof(size_t)*8 - 32);
             case 4: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[3]) << 24;
             case 3: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[2]) << 16;
             case 2: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[1]) <<  8;
             default:;
         }
         contain32 = ((const BYTE*)srcBuffer)[srcSize-1];
         if (contain32 == 0) return (size_t)-FSE_ERROR_GENERIC;   /* stop bit not present */
         bitD->bitsConsumed = 8 - FSE_highbit32(contain32);
         bitD->bitsConsumed += (U32)(sizeof(size_t) - srcSize)*8;
     }
 
     return srcSize;
 }
 
 
 /*!FSE_lookBits
  * Provides next n bits from the bitContainer.
  * bitContainer is not modified (bits are still present for next read/look)
  * On 32-bits, maxNbBits==25
  * On 64-bits, maxNbBits==57
  * return : value extracted.
  */
 static size_t FSE_lookBits(FSE_DStream_t* bitD, U32 nbBits)
 {
     const U32 bitMask = sizeof(bitD->bitContainer)*8 - 1;
     return ((bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> 1) >> ((bitMask-nbBits) & bitMask);
 }
 
 static size_t FSE_lookBitsFast(FSE_DStream_t* bitD, U32 nbBits)   /* only if nbBits >= 1 !! */
 {
     const U32 bitMask = sizeof(bitD->bitContainer)*8 - 1;
     return (bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> (((bitMask+1)-nbBits) & bitMask);
 }
 
 static void FSE_skipBits(FSE_DStream_t* bitD, U32 nbBits)
 {
     bitD->bitsConsumed += nbBits;
 }
 
 
 /*!FSE_readBits
  * Read next n bits from the bitContainer.
  * On 32-bits, don't read more than maxNbBits==25
  * On 64-bits, don't read more than maxNbBits==57
  * Use the fast variant *only* if n >= 1.
  * return : value extracted.
  */
 static size_t FSE_readBits(FSE_DStream_t* bitD, U32 nbBits)
 {
     size_t value = FSE_lookBits(bitD, nbBits);
     FSE_skipBits(bitD, nbBits);
     return value;
 }
 
 static size_t FSE_readBitsFast(FSE_DStream_t* bitD, U32 nbBits)   /* only if nbBits >= 1 !! */
 {
     size_t value = FSE_lookBitsFast(bitD, nbBits);
     FSE_skipBits(bitD, nbBits);
     return value;
 }
 
 static unsigned FSE_reloadDStream(FSE_DStream_t* bitD)
 {
     if (bitD->bitsConsumed > (sizeof(bitD->bitContainer)*8))  /* should never happen */
         return FSE_DStream_tooFar;
 
     if (bitD->ptr >= bitD->start + sizeof(bitD->bitContainer))
     {
         bitD->ptr -= bitD->bitsConsumed >> 3;
         bitD->bitsConsumed &= 7;
         bitD->bitContainer = FSE_readLEST(bitD->ptr);
         return FSE_DStream_unfinished;
     }
     if (bitD->ptr == bitD->start)
     {
         if (bitD->bitsConsumed < sizeof(bitD->bitContainer)*8) return FSE_DStream_endOfBuffer;
         return FSE_DStream_completed;
     }
     {
         U32 nbBytes = bitD->bitsConsumed >> 3;
         U32 result = FSE_DStream_unfinished;
         if (bitD->ptr - nbBytes < bitD->start)
         {
             nbBytes = (U32)(bitD->ptr - bitD->start);  /* ptr > start */
             result = FSE_DStream_endOfBuffer;
         }
         bitD->ptr -= nbBytes;
         bitD->bitsConsumed -= nbBytes*8;
         bitD->bitContainer = FSE_readLEST(bitD->ptr);   /* reminder : srcSize > sizeof(bitD) */
         return result;
     }
 }
 
 
 static void FSE_initDState(FSE_DState_t* DStatePtr, FSE_DStream_t* bitD, const FSE_DTable* dt)
 {
     const void* ptr = dt;
     const FSE_DTableHeader* const DTableH = (const FSE_DTableHeader*)ptr;
     DStatePtr->state = FSE_readBits(bitD, DTableH->tableLog);
     FSE_reloadDStream(bitD);
     DStatePtr->table = dt + 1;
 }
 
 static BYTE FSE_decodeSymbol(FSE_DState_t* DStatePtr, FSE_DStream_t* bitD)
 {
     const FSE_decode_t DInfo = ((const FSE_decode_t*)(DStatePtr->table))[DStatePtr->state];
     const U32  nbBits = DInfo.nbBits;
     BYTE symbol = DInfo.symbol;
     size_t lowBits = FSE_readBits(bitD, nbBits);
 
     DStatePtr->state = DInfo.newState + lowBits;
     return symbol;
 }
 
 static BYTE FSE_decodeSymbolFast(FSE_DState_t* DStatePtr, FSE_DStream_t* bitD)
 {
     const FSE_decode_t DInfo = ((const FSE_decode_t*)(DStatePtr->table))[DStatePtr->state];
     const U32 nbBits = DInfo.nbBits;
     BYTE symbol = DInfo.symbol;
     size_t lowBits = FSE_readBitsFast(bitD, nbBits);
 
     DStatePtr->state = DInfo.newState + lowBits;
     return symbol;
 }
 
 /* FSE_endOfDStream
    Tells if bitD has reached end of bitStream or not */
 
 static unsigned FSE_endOfDStream(const FSE_DStream_t* bitD)
 {
     return ((bitD->ptr == bitD->start) && (bitD->bitsConsumed == sizeof(bitD->bitContainer)*8));
 }
 
 static unsigned FSE_endOfDState(const FSE_DState_t* DStatePtr)
 {
     return DStatePtr->state == 0;
 }
 
 
 FORCE_INLINE size_t FSE_decompress_usingDTable_generic(
           void* dst, size_t maxDstSize,
     const void* cSrc, size_t cSrcSize,
     const FSE_DTable* dt, const unsigned fast)
 {
     BYTE* const ostart = (BYTE*) dst;
     BYTE* op = ostart;
     BYTE* const omax = op + maxDstSize;
     BYTE* const olimit = omax-3;
 
     FSE_DStream_t bitD;
     FSE_DState_t state1;
     FSE_DState_t state2;
     size_t errorCode;
 
     /* Init */
     errorCode = FSE_initDStream(&bitD, cSrc, cSrcSize);   /* replaced last arg by maxCompressed Size */
     if (FSE_isError(errorCode)) return errorCode;
 
     FSE_initDState(&state1, &bitD, dt);
     FSE_initDState(&state2, &bitD, dt);
 
 #define FSE_GETSYMBOL(statePtr) fast ? FSE_decodeSymbolFast(statePtr, &bitD) : FSE_decodeSymbol(statePtr, &bitD)
 
     /* 4 symbols per loop */
     for ( ; (FSE_reloadDStream(&bitD)==FSE_DStream_unfinished) && (op sizeof(bitD.bitContainer)*8)    /* This test must be static */
             FSE_reloadDStream(&bitD);
 
         op[1] = FSE_GETSYMBOL(&state2);
 
         if (FSE_MAX_TABLELOG*4+7 > sizeof(bitD.bitContainer)*8)    /* This test must be static */
             { if (FSE_reloadDStream(&bitD) > FSE_DStream_unfinished) { op+=2; break; } }
 
         op[2] = FSE_GETSYMBOL(&state1);
 
         if (FSE_MAX_TABLELOG*2+7 > sizeof(bitD.bitContainer)*8)    /* This test must be static */
             FSE_reloadDStream(&bitD);
 
         op[3] = FSE_GETSYMBOL(&state2);
     }
 
     /* tail */
     /* note : FSE_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends at exactly FSE_DStream_completed */
     while (1)
     {
         if ( (FSE_reloadDStream(&bitD)>FSE_DStream_completed) || (op==omax) || (FSE_endOfDStream(&bitD) && (fast || FSE_endOfDState(&state1))) )
             break;
 
         *op++ = FSE_GETSYMBOL(&state1);
 
         if ( (FSE_reloadDStream(&bitD)>FSE_DStream_completed) || (op==omax) || (FSE_endOfDStream(&bitD) && (fast || FSE_endOfDState(&state2))) )
             break;
 
         *op++ = FSE_GETSYMBOL(&state2);
     }
 
     /* end ? */
     if (FSE_endOfDStream(&bitD) && FSE_endOfDState(&state1) && FSE_endOfDState(&state2))
         return op-ostart;
 
     if (op==omax) return (size_t)-FSE_ERROR_dstSize_tooSmall;   /* dst buffer is full, but cSrc unfinished */
 
     return (size_t)-FSE_ERROR_corruptionDetected;
 }
 
 
 static size_t FSE_decompress_usingDTable(void* dst, size_t originalSize,
                             const void* cSrc, size_t cSrcSize,
                             const FSE_DTable* dt)
 {
     FSE_DTableHeader DTableH;
     memcpy(&DTableH, dt, sizeof(DTableH));   /* memcpy() into local variable, to avoid strict aliasing warning */
 
     /* select fast mode (static) */
     if (DTableH.fastMode) return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 1);
     return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 0);
 }
 
 
 static size_t FSE_decompress(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize)
 {
     const BYTE* const istart = (const BYTE*)cSrc;
     const BYTE* ip = istart;
     short counting[FSE_MAX_SYMBOL_VALUE+1];
     DTable_max_t dt;   /* Static analyzer seems unable to understand this table will be properly initialized later */
     unsigned tableLog;
     unsigned maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
     size_t errorCode;
 
     if (cSrcSize<2) return (size_t)-FSE_ERROR_srcSize_wrong;   /* too small input size */
 
     /* normal FSE decoding mode */
     errorCode = FSE_readNCount (counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
     if (FSE_isError(errorCode)) return errorCode;
     if (errorCode >= cSrcSize) return (size_t)-FSE_ERROR_srcSize_wrong;   /* too small input size */
     ip += errorCode;
     cSrcSize -= errorCode;
 
     errorCode = FSE_buildDTable (dt, counting, maxSymbolValue, tableLog);
     if (FSE_isError(errorCode)) return errorCode;
 
     /* always return, even if it is an error code */
     return FSE_decompress_usingDTable (dst, maxDstSize, ip, cSrcSize, dt);
 }
 
 
 
 /* *******************************************************
 *  Huff0 : Huffman block compression
 *********************************************************/
 #define HUF_MAX_SYMBOL_VALUE 255
 #define HUF_DEFAULT_TABLELOG  12       /* used by default, when not specified */
 #define HUF_MAX_TABLELOG  12           /* max possible tableLog; for allocation purpose; can be modified */
 #define HUF_ABSOLUTEMAX_TABLELOG  16   /* absolute limit of HUF_MAX_TABLELOG. Beyond that value, code does not work */
 #if (HUF_MAX_TABLELOG > HUF_ABSOLUTEMAX_TABLELOG)
 #  error "HUF_MAX_TABLELOG is too large !"
 #endif
 
 typedef struct HUF_CElt_s {
   U16  val;
   BYTE nbBits;
 } HUF_CElt ;
 
 typedef struct nodeElt_s {
     U32 count;
     U16 parent;
     BYTE byte;
     BYTE nbBits;
 } nodeElt;
 
 
 /* *******************************************************
 *  Huff0 : Huffman block decompression
 *********************************************************/
 typedef struct {
     BYTE byte;
     BYTE nbBits;
 } HUF_DElt;
 
 static size_t HUF_readDTable (U16* DTable, const void* src, size_t srcSize)
 {
     BYTE huffWeight[HUF_MAX_SYMBOL_VALUE + 1];
     U32 rankVal[HUF_ABSOLUTEMAX_TABLELOG + 1];  /* large enough for values from 0 to 16 */
     U32 weightTotal;
     U32 maxBits;
     const BYTE* ip = (const BYTE*) src;
     size_t iSize;
     size_t oSize;
     U32 n;
     U32 nextRankStart;
     void* ptr = DTable+1;
     HUF_DElt* const dt = (HUF_DElt*)ptr;
 
     if (!srcSize) return (size_t)-FSE_ERROR_srcSize_wrong;
     iSize = ip[0];
 
     FSE_STATIC_ASSERT(sizeof(HUF_DElt) == sizeof(U16));   /* if compilation fails here, assertion is false */
     //memset(huffWeight, 0, sizeof(huffWeight));   /* should not be necessary, but some analyzer complain ... */
     if (iSize >= 128)  /* special header */
     {
         if (iSize >= (242))   /* RLE */
         {
             static int l[14] = { 1, 2, 3, 4, 7, 8, 15, 16, 31, 32, 63, 64, 127, 128 };
             oSize = l[iSize-242];
             memset(huffWeight, 1, sizeof(huffWeight));
             iSize = 0;
         }
         else   /* Incompressible */
         {
             oSize = iSize - 127;
             iSize = ((oSize+1)/2);
             if (iSize+1 > srcSize) return (size_t)-FSE_ERROR_srcSize_wrong;
             ip += 1;
             for (n=0; n> 4;
                 huffWeight[n+1] = ip[n/2] & 15;
             }
         }
     }
     else  /* header compressed with FSE (normal case) */
     {
         if (iSize+1 > srcSize) return (size_t)-FSE_ERROR_srcSize_wrong;
         oSize = FSE_decompress(huffWeight, HUF_MAX_SYMBOL_VALUE, ip+1, iSize);   /* max 255 values decoded, last one is implied */
         if (FSE_isError(oSize)) return oSize;
     }
 
     /* collect weight stats */
     memset(rankVal, 0, sizeof(rankVal));
     weightTotal = 0;
     for (n=0; n= HUF_ABSOLUTEMAX_TABLELOG) return (size_t)-FSE_ERROR_corruptionDetected;
         rankVal[huffWeight[n]]++;
         weightTotal += (1 << huffWeight[n]) >> 1;
     }
     if (weightTotal == 0) return (size_t)-FSE_ERROR_corruptionDetected;
 
     /* get last non-null symbol weight (implied, total must be 2^n) */
     maxBits = FSE_highbit32(weightTotal) + 1;
     if (maxBits > DTable[0]) return (size_t)-FSE_ERROR_tableLog_tooLarge;   /* DTable is too small */
     DTable[0] = (U16)maxBits;
     {
         U32 total = 1 << maxBits;
         U32 rest = total - weightTotal;
         U32 verif = 1 << FSE_highbit32(rest);
         U32 lastWeight = FSE_highbit32(rest) + 1;
         if (verif != rest) return (size_t)-FSE_ERROR_corruptionDetected;    /* last value must be a clean power of 2 */
         huffWeight[oSize] = (BYTE)lastWeight;
         rankVal[lastWeight]++;
     }
 
     /* check tree construction validity */
     if ((rankVal[1] < 2) || (rankVal[1] & 1)) return (size_t)-FSE_ERROR_corruptionDetected;   /* by construction : at least 2 elts of rank 1, must be even */
 
     /* Prepare ranks */
     nextRankStart = 0;
     for (n=1; n<=maxBits; n++)
     {
         U32 current = nextRankStart;
         nextRankStart += (rankVal[n] << (n-1));
         rankVal[n] = current;
     }
 
     /* fill DTable */
     for (n=0; n<=oSize; n++)
     {
         const U32 w = huffWeight[n];
         const U32 length = (1 << w) >> 1;
         U32 i;
         HUF_DElt D;
         D.byte = (BYTE)n; D.nbBits = (BYTE)(maxBits + 1 - w);
         for (i = rankVal[w]; i < rankVal[w] + length; i++)
             dt[i] = D;
         rankVal[w] += length;
     }
 
     return iSize+1;
 }
 
 
 static BYTE HUF_decodeSymbol(FSE_DStream_t* Dstream, const HUF_DElt* dt, const U32 dtLog)
 {
         const size_t val = FSE_lookBitsFast(Dstream, dtLog); /* note : dtLog >= 1 */
         const BYTE c = dt[val].byte;
         FSE_skipBits(Dstream, dt[val].nbBits);
         return c;
 }
 
 static size_t HUF_decompress_usingDTable(   /* -3% slower when non static */
           void* dst, size_t maxDstSize,
     const void* cSrc, size_t cSrcSize,
     const U16* DTable)
 {
     BYTE* const ostart = (BYTE*) dst;
     BYTE* op = ostart;
     BYTE* const omax = op + maxDstSize;
     BYTE* const olimit = omax-15;
 
     const void* ptr = DTable;
     const HUF_DElt* const dt = (const HUF_DElt*)(ptr)+1;
     const U32 dtLog = DTable[0];
     size_t errorCode;
     U32 reloadStatus;
 
     /* Init */
 
     const U16* jumpTable = (const U16*)cSrc;
     const size_t length1 = FSE_readLE16(jumpTable);
     const size_t length2 = FSE_readLE16(jumpTable+1);
     const size_t length3 = FSE_readLE16(jumpTable+2);
     const size_t length4 = cSrcSize - 6 - length1 - length2 - length3;   // check coherency !!
     const char* const start1 = (const char*)(cSrc) + 6;
     const char* const start2 = start1 + length1;
     const char* const start3 = start2 + length2;
     const char* const start4 = start3 + length3;
     FSE_DStream_t bitD1, bitD2, bitD3, bitD4;
 
     if (length1+length2+length3+6 >= cSrcSize) return (size_t)-FSE_ERROR_srcSize_wrong;
 
     errorCode = FSE_initDStream(&bitD1, start1, length1);
     if (FSE_isError(errorCode)) return errorCode;
     errorCode = FSE_initDStream(&bitD2, start2, length2);
     if (FSE_isError(errorCode)) return errorCode;
     errorCode = FSE_initDStream(&bitD3, start3, length3);
     if (FSE_isError(errorCode)) return errorCode;
     errorCode = FSE_initDStream(&bitD4, start4, length4);
     if (FSE_isError(errorCode)) return errorCode;
 
     reloadStatus=FSE_reloadDStream(&bitD2);
 
     /* 16 symbols per loop */
     for ( ; (reloadStatus12)) FSE_reloadDStream(&Dstream)
 
 #define HUF_DECODE_SYMBOL_2(n, Dstream) \
         op[n] = HUF_decodeSymbol(&Dstream, dt, dtLog); \
         if (FSE_32bits()) FSE_reloadDStream(&Dstream)
 
         HUF_DECODE_SYMBOL_1( 0, bitD1);
         HUF_DECODE_SYMBOL_1( 1, bitD2);
         HUF_DECODE_SYMBOL_1( 2, bitD3);
         HUF_DECODE_SYMBOL_1( 3, bitD4);
         HUF_DECODE_SYMBOL_2( 4, bitD1);
         HUF_DECODE_SYMBOL_2( 5, bitD2);
         HUF_DECODE_SYMBOL_2( 6, bitD3);
         HUF_DECODE_SYMBOL_2( 7, bitD4);
         HUF_DECODE_SYMBOL_1( 8, bitD1);
         HUF_DECODE_SYMBOL_1( 9, bitD2);
         HUF_DECODE_SYMBOL_1(10, bitD3);
         HUF_DECODE_SYMBOL_1(11, bitD4);
         HUF_DECODE_SYMBOL_0(12, bitD1);
         HUF_DECODE_SYMBOL_0(13, bitD2);
         HUF_DECODE_SYMBOL_0(14, bitD3);
         HUF_DECODE_SYMBOL_0(15, bitD4);
     }
 
     if (reloadStatus!=FSE_DStream_completed)   /* not complete : some bitStream might be FSE_DStream_unfinished */
         return (size_t)-FSE_ERROR_corruptionDetected;
 
     /* tail */
     {
         // bitTail = bitD1;   // *much* slower : -20% !??!
         FSE_DStream_t bitTail;
         bitTail.ptr = bitD1.ptr;
         bitTail.bitsConsumed = bitD1.bitsConsumed;
         bitTail.bitContainer = bitD1.bitContainer;   // required in case of FSE_DStream_endOfBuffer
         bitTail.start = start1;
         for ( ; (FSE_reloadDStream(&bitTail) < FSE_DStream_completed) && (op= cSrcSize) return (size_t)-FSE_ERROR_srcSize_wrong;
     ip += errorCode;
     cSrcSize -= errorCode;
 
     return HUF_decompress_usingDTable (dst, maxDstSize, ip, cSrcSize, DTable);
 }
 
 
 #endif   /* FSE_COMMONDEFS_ONLY */
 
 /*
     zstd - standard compression library
     Copyright (C) 2014-2015, Yann Collet.
 
     BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions are
     met:
     * Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
     * Redistributions in binary form must reproduce the above
     copyright notice, this list of conditions and the following disclaimer
     in the documentation and/or other materials provided with the
     distribution.
     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
     You can contact the author at :
     - zstd source repository : https://github.com/Cyan4973/zstd
     - ztsd public forum : https://groups.google.com/forum/#!forum/lz4c
 */
 
 /****************************************************************
 *  Tuning parameters
 *****************************************************************/
 /* MEMORY_USAGE :
 *  Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
 *  Increasing memory usage improves compression ratio
 *  Reduced memory usage can improve speed, due to cache effect */
 #define ZSTD_MEMORY_USAGE 17
 
 
 /**************************************
    CPU Feature Detection
 **************************************/
 /*
  * Automated efficient unaligned memory access detection
  * Based on known hardware architectures
  * This list will be updated thanks to feedbacks
  */
 #if defined(CPU_HAS_EFFICIENT_UNALIGNED_MEMORY_ACCESS) \
     || defined(__ARM_FEATURE_UNALIGNED) \
     || defined(__i386__) || defined(__x86_64__) \
     || defined(_M_IX86) || defined(_M_X64) \
     || defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_8__) \
     || (defined(_M_ARM) && (_M_ARM >= 7))
 #  define ZSTD_UNALIGNED_ACCESS 1
 #else
 #  define ZSTD_UNALIGNED_ACCESS 0
 #endif
 
 
 /********************************************************
 *  Includes
 *********************************************************/
 #include       /* calloc */
 #include       /* memcpy, memmove */
 #include        /* debug : printf */
 
 
 /********************************************************
 *  Compiler specifics
 *********************************************************/
 #ifdef __AVX2__
 #  include    /* AVX2 intrinsics */
 #endif
 
 #ifdef _MSC_VER    /* Visual Studio */
 #  include                     /* For Visual 2005 */
 #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
 #  pragma warning(disable : 4324)        /* disable: C4324: padded structure */
 #endif
 
 
 #ifndef MEM_ACCESS_MODULE
 #define MEM_ACCESS_MODULE
 /********************************************************
 *  Basic Types
 *********************************************************/
 #if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
 # include 
 typedef  uint8_t BYTE;
 typedef uint16_t U16;
 typedef  int16_t S16;
 typedef uint32_t U32;
 typedef  int32_t S32;
 typedef uint64_t U64;
 #else
 typedef unsigned char       BYTE;
 typedef unsigned short      U16;
 typedef   signed short      S16;
 typedef unsigned int        U32;
 typedef   signed int        S32;
 typedef unsigned long long  U64;
 #endif
 
 #endif   /* MEM_ACCESS_MODULE */
 
 
 /********************************************************
 *  Constants
 *********************************************************/
 static const U32 ZSTD_magicNumber = 0xFD2FB51E;   /* 3rd version : seqNb header */
 
 #define HASH_LOG (ZSTD_MEMORY_USAGE - 2)
 #define HASH_TABLESIZE (1 << HASH_LOG)
 #define HASH_MASK (HASH_TABLESIZE - 1)
 
 #define KNUTH 2654435761
 
 #define BIT7 128
 #define BIT6  64
 #define BIT5  32
 #define BIT4  16
 
 #define KB *(1 <<10)
 #define MB *(1 <<20)
 #define GB *(1U<<30)
 
 #define BLOCKSIZE (128 KB)                 /* define, for static allocation */
 
 #define WORKPLACESIZE (BLOCKSIZE*3)
 #define MINMATCH 4
 #define MLbits   7
 #define LLbits   6
 #define Offbits  5
 #define MaxML  ((1<>3];
 #else
     U32 hashTable[HASH_TABLESIZE];
 #endif
     BYTE buffer[WORKPLACESIZE];
 } cctxi_t;
 
 
 
 
 /**************************************
 *  Error Management
 **************************************/
 /* published entry point */
 unsigned ZSTDv01_isError(size_t code) { return ERR_isError(code); }
 
 
 /**************************************
 *  Tool functions
 **************************************/
 #define ZSTD_VERSION_MAJOR    0    /* for breaking interface changes  */
 #define ZSTD_VERSION_MINOR    1    /* for new (non-breaking) interface capabilities */
 #define ZSTD_VERSION_RELEASE  3    /* for tweaks, bug-fixes, or development */
 #define ZSTD_VERSION_NUMBER  (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)
 
 /**************************************************************
 *   Decompression code
 **************************************************************/
 
 size_t ZSTDv01_getcBlockSize(const void* src, size_t srcSize, blockProperties_t* bpPtr)
 {
     const BYTE* const in = (const BYTE* const)src;
     BYTE headerFlags;
     U32 cSize;
 
     if (srcSize < 3) return ERROR(srcSize_wrong);
 
     headerFlags = *in;
     cSize = in[2] + (in[1]<<8) + ((in[0] & 7)<<16);
 
     bpPtr->blockType = (blockType_t)(headerFlags >> 6);
     bpPtr->origSize = (bpPtr->blockType == bt_rle) ? cSize : 0;
 
     if (bpPtr->blockType == bt_end) return 0;
     if (bpPtr->blockType == bt_rle) return 1;
     return cSize;
 }
 
 
 static size_t ZSTD_copyUncompressedBlock(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
 {
     if (srcSize > maxDstSize) return ERROR(dstSize_tooSmall);
     memcpy(dst, src, srcSize);
     return srcSize;
 }
 
 
 static size_t ZSTD_decompressLiterals(void* ctx,
                                       void* dst, size_t maxDstSize,
                                 const void* src, size_t srcSize)
 {
     BYTE* op = (BYTE*)dst;
     BYTE* const oend = op + maxDstSize;
     const BYTE* ip = (const BYTE*)src;
     size_t errorCode;
     size_t litSize;
 
     /* check : minimum 2, for litSize, +1, for content */
     if (srcSize <= 3) return ERROR(corruption_detected);
 
     litSize = ip[1] + (ip[0]<<8);
     litSize += ((ip[-3] >> 3) & 7) << 16;   // mmmmh....
     op = oend - litSize;
 
     (void)ctx;
     if (litSize > maxDstSize) return ERROR(dstSize_tooSmall);
     errorCode = HUF_decompress(op, litSize, ip+2, srcSize-2);
     if (FSE_isError(errorCode)) return ERROR(GENERIC);
     return litSize;
 }
 
 
 size_t ZSTDv01_decodeLiteralsBlock(void* ctx,
                                 void* dst, size_t maxDstSize,
                           const BYTE** litStart, size_t* litSize,
                           const void* src, size_t srcSize)
 {
     const BYTE* const istart = (const BYTE* const)src;
     const BYTE* ip = istart;
     BYTE* const ostart = (BYTE* const)dst;
     BYTE* const oend = ostart + maxDstSize;
     blockProperties_t litbp;
 
     size_t litcSize = ZSTDv01_getcBlockSize(src, srcSize, &litbp);
     if (ZSTDv01_isError(litcSize)) return litcSize;
     if (litcSize > srcSize - ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
     ip += ZSTD_blockHeaderSize;
 
     switch(litbp.blockType)
     {
     case bt_raw:
         *litStart = ip;
         ip += litcSize;
         *litSize = litcSize;
         break;
     case bt_rle:
         {
             size_t rleSize = litbp.origSize;
             if (rleSize>maxDstSize) return ERROR(dstSize_tooSmall);
             if (!srcSize) return ERROR(srcSize_wrong);
             memset(oend - rleSize, *ip, rleSize);
             *litStart = oend - rleSize;
             *litSize = rleSize;
             ip++;
             break;
         }
     case bt_compressed:
         {
             size_t decodedLitSize = ZSTD_decompressLiterals(ctx, dst, maxDstSize, ip, litcSize);
             if (ZSTDv01_isError(decodedLitSize)) return decodedLitSize;
             *litStart = oend - decodedLitSize;
             *litSize = decodedLitSize;
             ip += litcSize;
             break;
         }
     case bt_end:
     default:
         return ERROR(GENERIC);
     }
 
     return ip-istart;
 }
 
 
 size_t ZSTDv01_decodeSeqHeaders(int* nbSeq, const BYTE** dumpsPtr, size_t* dumpsLengthPtr,
                          FSE_DTable* DTableLL, FSE_DTable* DTableML, FSE_DTable* DTableOffb,
                          const void* src, size_t srcSize)
 {
     const BYTE* const istart = (const BYTE* const)src;
     const BYTE* ip = istart;
     const BYTE* const iend = istart + srcSize;
     U32 LLtype, Offtype, MLtype;
     U32 LLlog, Offlog, MLlog;
     size_t dumpsLength;
 
     /* check */
     if (srcSize < 5) return ERROR(srcSize_wrong);
 
     /* SeqHead */
     *nbSeq = ZSTD_readLE16(ip); ip+=2;
     LLtype  = *ip >> 6;
     Offtype = (*ip >> 4) & 3;
     MLtype  = (*ip >> 2) & 3;
     if (*ip & 2)
     {
         dumpsLength  = ip[2];
         dumpsLength += ip[1] << 8;
         ip += 3;
     }
     else
     {
         dumpsLength  = ip[1];
         dumpsLength += (ip[0] & 1) << 8;
         ip += 2;
     }
     *dumpsPtr = ip;
     ip += dumpsLength;
     *dumpsLengthPtr = dumpsLength;
 
     /* check */
     if (ip > iend-3) return ERROR(srcSize_wrong); /* min : all 3 are "raw", hence no header, but at least xxLog bits per type */
 
     /* sequences */
     {
         S16 norm[MaxML+1];    /* assumption : MaxML >= MaxLL and MaxOff */
         size_t headerSize;
 
         /* Build DTables */
         switch(LLtype)
         {
         case bt_rle :
             LLlog = 0;
             FSE_buildDTable_rle(DTableLL, *ip++); break;
         case bt_raw :
             LLlog = LLbits;
             FSE_buildDTable_raw(DTableLL, LLbits); break;
         default :
             {   U32 max = MaxLL;
                 headerSize = FSE_readNCount(norm, &max, &LLlog, ip, iend-ip);
                 if (FSE_isError(headerSize)) return ERROR(GENERIC);
                 if (LLlog > LLFSELog) return ERROR(corruption_detected);
                 ip += headerSize;
                 FSE_buildDTable(DTableLL, norm, max, LLlog);
         }   }
 
         switch(Offtype)
         {
         case bt_rle :
             Offlog = 0;
             if (ip > iend-2) return ERROR(srcSize_wrong); /* min : "raw", hence no header, but at least xxLog bits */
             FSE_buildDTable_rle(DTableOffb, *ip++); break;
         case bt_raw :
             Offlog = Offbits;
             FSE_buildDTable_raw(DTableOffb, Offbits); break;
         default :
             {   U32 max = MaxOff;
                 headerSize = FSE_readNCount(norm, &max, &Offlog, ip, iend-ip);
                 if (FSE_isError(headerSize)) return ERROR(GENERIC);
                 if (Offlog > OffFSELog) return ERROR(corruption_detected);
                 ip += headerSize;
                 FSE_buildDTable(DTableOffb, norm, max, Offlog);
         }   }
 
         switch(MLtype)
         {
         case bt_rle :
             MLlog = 0;
             if (ip > iend-2) return ERROR(srcSize_wrong); /* min : "raw", hence no header, but at least xxLog bits */
             FSE_buildDTable_rle(DTableML, *ip++); break;
         case bt_raw :
             MLlog = MLbits;
             FSE_buildDTable_raw(DTableML, MLbits); break;
         default :
             {   U32 max = MaxML;
                 headerSize = FSE_readNCount(norm, &max, &MLlog, ip, iend-ip);
                 if (FSE_isError(headerSize)) return ERROR(GENERIC);
                 if (MLlog > MLFSELog) return ERROR(corruption_detected);
                 ip += headerSize;
                 FSE_buildDTable(DTableML, norm, max, MLlog);
     }   }   }
 
     return ip-istart;
 }
 
 
 typedef struct {
     size_t litLength;
     size_t offset;
     size_t matchLength;
 } seq_t;
 
 typedef struct {
     FSE_DStream_t DStream;
     FSE_DState_t stateLL;
     FSE_DState_t stateOffb;
     FSE_DState_t stateML;
     size_t prevOffset;
     const BYTE* dumps;
     const BYTE* dumpsEnd;
 } seqState_t;
 
 
 static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState)
 {
     size_t litLength;
     size_t prevOffset;
     size_t offset;
     size_t matchLength;
     const BYTE* dumps = seqState->dumps;
     const BYTE* const de = seqState->dumpsEnd;
 
     /* Literal length */
     litLength = FSE_decodeSymbol(&(seqState->stateLL), &(seqState->DStream));
     prevOffset = litLength ? seq->offset : seqState->prevOffset;
     seqState->prevOffset = seq->offset;
     if (litLength == MaxLL)
     {
         U32 add = dumps 1 byte */
                 dumps += 3;
             }
         }
     }
 
     /* Offset */
     {
         U32 offsetCode, nbBits;
         offsetCode = FSE_decodeSymbol(&(seqState->stateOffb), &(seqState->DStream));
         if (ZSTD_32bits()) FSE_reloadDStream(&(seqState->DStream));
         nbBits = offsetCode - 1;
         if (offsetCode==0) nbBits = 0;   /* cmove */
         offset = ((size_t)1 << (nbBits & ((sizeof(offset)*8)-1))) + FSE_readBits(&(seqState->DStream), nbBits);
         if (ZSTD_32bits()) FSE_reloadDStream(&(seqState->DStream));
         if (offsetCode==0) offset = prevOffset;
     }
 
     /* MatchLength */
     matchLength = FSE_decodeSymbol(&(seqState->stateML), &(seqState->DStream));
     if (matchLength == MaxML)
     {
         U32 add = dumps 1 byte */
                 dumps += 3;
             }
         }
     }
     matchLength += MINMATCH;
 
     /* save result */
     seq->litLength = litLength;
     seq->offset = offset;
     seq->matchLength = matchLength;
     seqState->dumps = dumps;
 }
 
 
 static size_t ZSTD_execSequence(BYTE* op,
                                 seq_t sequence,
                                 const BYTE** litPtr, const BYTE* const litLimit,
                                 BYTE* const base, BYTE* const oend)
 {
     static const int dec32table[] = {0, 1, 2, 1, 4, 4, 4, 4};   /* added */
     static const int dec64table[] = {8, 8, 8, 7, 8, 9,10,11};   /* substracted */
     const BYTE* const ostart = op;
     const size_t litLength = sequence.litLength;
     BYTE* const endMatch = op + litLength + sequence.matchLength;    /* risk : address space overflow (32-bits) */
     const BYTE* const litEnd = *litPtr + litLength;
 
     /* check */
     if (endMatch > oend) return ERROR(dstSize_tooSmall);   /* overwrite beyond dst buffer */
     if (litEnd > litLimit) return ERROR(corruption_detected);
     if (sequence.matchLength > (size_t)(*litPtr-op))  return ERROR(dstSize_tooSmall);    /* overwrite literal segment */
 
     /* copy Literals */
     if (((size_t)(*litPtr - op) < 8) || ((size_t)(oend-litEnd) < 8) || (op+litLength > oend-8))
         memmove(op, *litPtr, litLength);   /* overwrite risk */
     else
         ZSTD_wildcopy(op, *litPtr, litLength);
     op += litLength;
     *litPtr = litEnd;   /* update for next sequence */
 
     /* check : last match must be at a minimum distance of 8 from end of dest buffer */
     if (oend-op < 8) return ERROR(dstSize_tooSmall);
 
     /* copy Match */
     {
         const U32 overlapRisk = (((size_t)(litEnd - endMatch)) < 12);
         const BYTE* match = op - sequence.offset;            /* possible underflow at op - offset ? */
         size_t qutt = 12;
         U64 saved[2];
 
         /* check */
         if (match < base) return ERROR(corruption_detected);
         if (sequence.offset > (size_t)base) return ERROR(corruption_detected);
 
         /* save beginning of literal sequence, in case of write overlap */
         if (overlapRisk)
         {
             if ((endMatch + qutt) > oend) qutt = oend-endMatch;
             memcpy(saved, endMatch, qutt);
         }
 
         if (sequence.offset < 8)
         {
             const int dec64 = dec64table[sequence.offset];
             op[0] = match[0];
             op[1] = match[1];
             op[2] = match[2];
             op[3] = match[3];
             match += dec32table[sequence.offset];
             ZSTD_copy4(op+4, match);
             match -= dec64;
         } else { ZSTD_copy8(op, match); }
         op += 8; match += 8;
 
         if (endMatch > oend-(16-MINMATCH))
         {
             if (op < oend-8)
             {
                 ZSTD_wildcopy(op, match, (oend-8) - op);
                 match += (oend-8) - op;
                 op = oend-8;
             }
             while (opLLTable;
     U32* DTableML = dctx->MLTable;
     U32* DTableOffb = dctx->OffTable;
     BYTE* const base = (BYTE*) (dctx->base);
 
     /* Build Decoding Tables */
     errorCode = ZSTDv01_decodeSeqHeaders(&nbSeq, &dumps, &dumpsLength,
                                       DTableLL, DTableML, DTableOffb,
                                       ip, iend-ip);
     if (ZSTDv01_isError(errorCode)) return errorCode;
     ip += errorCode;
 
     /* Regen sequences */
     {
         seq_t sequence;
         seqState_t seqState;
 
         memset(&sequence, 0, sizeof(sequence));
         seqState.dumps = dumps;
         seqState.dumpsEnd = dumps + dumpsLength;
         seqState.prevOffset = 1;
         errorCode = FSE_initDStream(&(seqState.DStream), ip, iend-ip);
         if (FSE_isError(errorCode)) return ERROR(corruption_detected);
         FSE_initDState(&(seqState.stateLL), &(seqState.DStream), DTableLL);
         FSE_initDState(&(seqState.stateOffb), &(seqState.DStream), DTableOffb);
         FSE_initDState(&(seqState.stateML), &(seqState.DStream), DTableML);
 
         for ( ; (FSE_reloadDStream(&(seqState.DStream)) <= FSE_DStream_completed) && (nbSeq>0) ; )
         {
             size_t oneSeqSize;
             nbSeq--;
             ZSTD_decodeSequence(&sequence, &seqState);
             oneSeqSize = ZSTD_execSequence(op, sequence, &litPtr, litEnd, base, oend);
             if (ZSTDv01_isError(oneSeqSize)) return oneSeqSize;
             op += oneSeqSize;
         }
 
         /* check if reached exact end */
         if ( !FSE_endOfDStream(&(seqState.DStream)) ) return ERROR(corruption_detected);   /* requested too much : data is corrupted */
         if (nbSeq<0) return ERROR(corruption_detected);   /* requested too many sequences : data is corrupted */
 
         /* last literal segment */
         {
             size_t lastLLSize = litEnd - litPtr;
             if (op+lastLLSize > oend) return ERROR(dstSize_tooSmall);
             if (op != litPtr) memmove(op, litPtr, lastLLSize);
             op += lastLLSize;
         }
     }
 
     return op-ostart;
 }
 
 
 static size_t ZSTD_decompressBlock(
                             void* ctx,
                             void* dst, size_t maxDstSize,
                       const void* src, size_t srcSize)
 {
     /* blockType == blockCompressed, srcSize is trusted */
     const BYTE* ip = (const BYTE*)src;
     const BYTE* litPtr = NULL;
     size_t litSize = 0;
     size_t errorCode;
 
     /* Decode literals sub-block */
     errorCode = ZSTDv01_decodeLiteralsBlock(ctx, dst, maxDstSize, &litPtr, &litSize, src, srcSize);
     if (ZSTDv01_isError(errorCode)) return errorCode;
     ip += errorCode;
     srcSize -= errorCode;
 
     return ZSTD_decompressSequences(ctx, dst, maxDstSize, ip, srcSize, litPtr, litSize);
 }
 
 
 size_t ZSTDv01_decompressDCtx(void* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
 {
     const BYTE* ip = (const BYTE*)src;
     const BYTE* iend = ip + srcSize;
     BYTE* const ostart = (BYTE* const)dst;
     BYTE* op = ostart;
     BYTE* const oend = ostart + maxDstSize;
     size_t remainingSize = srcSize;
     U32 magicNumber;
     size_t errorCode=0;
     blockProperties_t blockProperties;
 
     /* Frame Header */
     if (srcSize < ZSTD_frameHeaderSize+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
     magicNumber = ZSTD_readBE32(src);
     if (magicNumber != ZSTD_magicNumber) return ERROR(prefix_unknown);
     ip += ZSTD_frameHeaderSize; remainingSize -= ZSTD_frameHeaderSize;
 
     /* Loop on each block */
     while (1)
     {
         size_t blockSize = ZSTDv01_getcBlockSize(ip, iend-ip, &blockProperties);
         if (ZSTDv01_isError(blockSize)) return blockSize;
 
         ip += ZSTD_blockHeaderSize;
         remainingSize -= ZSTD_blockHeaderSize;
         if (blockSize > remainingSize) return ERROR(srcSize_wrong);
 
         switch(blockProperties.blockType)
         {
         case bt_compressed:
             errorCode = ZSTD_decompressBlock(ctx, op, oend-op, ip, blockSize);
             break;
         case bt_raw :
             errorCode = ZSTD_copyUncompressedBlock(op, oend-op, ip, blockSize);
             break;
         case bt_rle :
             return ERROR(GENERIC);   /* not yet supported */
             break;
         case bt_end :
             /* end of frame */
             if (remainingSize) return ERROR(srcSize_wrong);
             break;
         default:
             return ERROR(GENERIC);
         }
         if (blockSize == 0) break;   /* bt_end */
 
         if (ZSTDv01_isError(errorCode)) return errorCode;
         op += errorCode;
         ip += blockSize;
         remainingSize -= blockSize;
     }
 
     return op-ostart;
 }
 
 size_t ZSTDv01_decompress(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
 {
     dctx_t ctx;
     ctx.base = dst;
     return ZSTDv01_decompressDCtx(&ctx, dst, maxDstSize, src, srcSize);
 }
 
 size_t ZSTDv01_findFrameCompressedSize(const void* src, size_t srcSize)
 {
     const BYTE* ip = (const BYTE*)src;
     size_t remainingSize = srcSize;
     U32 magicNumber;
     blockProperties_t blockProperties;
 
     /* Frame Header */
     if (srcSize < ZSTD_frameHeaderSize+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
     magicNumber = ZSTD_readBE32(src);
     if (magicNumber != ZSTD_magicNumber) return ERROR(prefix_unknown);
     ip += ZSTD_frameHeaderSize; remainingSize -= ZSTD_frameHeaderSize;
 
     /* Loop on each block */
     while (1)
     {
         size_t blockSize = ZSTDv01_getcBlockSize(ip, remainingSize, &blockProperties);
         if (ZSTDv01_isError(blockSize)) return blockSize;
 
         ip += ZSTD_blockHeaderSize;
         remainingSize -= ZSTD_blockHeaderSize;
         if (blockSize > remainingSize) return ERROR(srcSize_wrong);
 
         if (blockSize == 0) break;   /* bt_end */
 
         ip += blockSize;
         remainingSize -= blockSize;
     }
 
     return ip - (const BYTE*)src;
 }
 
 /*******************************
 *  Streaming Decompression API
 *******************************/
 
 size_t ZSTDv01_resetDCtx(ZSTDv01_Dctx* dctx)
 {
     dctx->expected = ZSTD_frameHeaderSize;
     dctx->phase = 0;
     dctx->previousDstEnd = NULL;
     dctx->base = NULL;
     return 0;
 }
 
 ZSTDv01_Dctx* ZSTDv01_createDCtx(void)
 {
     ZSTDv01_Dctx* dctx = (ZSTDv01_Dctx*)malloc(sizeof(ZSTDv01_Dctx));
     if (dctx==NULL) return NULL;
     ZSTDv01_resetDCtx(dctx);
     return dctx;
 }
 
 size_t ZSTDv01_freeDCtx(ZSTDv01_Dctx* dctx)
 {
     free(dctx);
     return 0;
 }
 
 size_t ZSTDv01_nextSrcSizeToDecompress(ZSTDv01_Dctx* dctx)
 {
     return ((dctx_t*)dctx)->expected;
 }
 
 size_t ZSTDv01_decompressContinue(ZSTDv01_Dctx* dctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
 {
     dctx_t* ctx = (dctx_t*)dctx;
 
     /* Sanity check */
     if (srcSize != ctx->expected) return ERROR(srcSize_wrong);
     if (dst != ctx->previousDstEnd)  /* not contiguous */
         ctx->base = dst;
 
     /* Decompress : frame header */
     if (ctx->phase == 0)
     {
         /* Check frame magic header */
         U32 magicNumber = ZSTD_readBE32(src);
         if (magicNumber != ZSTD_magicNumber) return ERROR(prefix_unknown);
         ctx->phase = 1;
         ctx->expected = ZSTD_blockHeaderSize;
         return 0;
     }
 
     /* Decompress : block header */
     if (ctx->phase == 1)
     {
         blockProperties_t bp;
         size_t blockSize = ZSTDv01_getcBlockSize(src, ZSTD_blockHeaderSize, &bp);
         if (ZSTDv01_isError(blockSize)) return blockSize;
         if (bp.blockType == bt_end)
         {
             ctx->expected = 0;
             ctx->phase = 0;
         }
         else
         {
             ctx->expected = blockSize;
             ctx->bType = bp.blockType;
             ctx->phase = 2;
         }
 
         return 0;
     }
 
     /* Decompress : block content */
     {
         size_t rSize;
         switch(ctx->bType)
         {
         case bt_compressed:
             rSize = ZSTD_decompressBlock(ctx, dst, maxDstSize, src, srcSize);
             break;
         case bt_raw :
             rSize = ZSTD_copyUncompressedBlock(dst, maxDstSize, src, srcSize);
             break;
         case bt_rle :
             return ERROR(GENERIC);   /* not yet handled */
             break;
         case bt_end :   /* should never happen (filtered at phase 1) */
             rSize = 0;
             break;
         default:
             return ERROR(GENERIC);
         }
         ctx->phase = 1;
         ctx->expected = ZSTD_blockHeaderSize;
         ctx->previousDstEnd = (void*)( ((char*)dst) + rSize);
         return rSize;
     }
 
 }
Index: head/sys/contrib/zstd/lib/legacy/zstd_v02.c
===================================================================
--- head/sys/contrib/zstd/lib/legacy/zstd_v02.c	(revision 330893)
+++ head/sys/contrib/zstd/lib/legacy/zstd_v02.c	(revision 330894)
@@ -1,3556 +1,3483 @@
 /*
  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  * All rights reserved.
  *
  * This source code is licensed under both the BSD-style license (found in the
  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
 
 
 #include     /* size_t, ptrdiff_t */
 #include "zstd_v02.h"
 #include "error_private.h"
 
 
 /******************************************
 *  Compiler-specific
 ******************************************/
 #if defined(_MSC_VER)   /* Visual Studio */
 #   include   /* _byteswap_ulong */
 #   include   /* _byteswap_* */
 #endif
 
 
 /* ******************************************************************
    mem.h
    low-level memory access routines
    Copyright (C) 2013-2015, Yann Collet.
 
    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:
 
        * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following disclaimer
    in the documentation and/or other materials provided with the
    distribution.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
     You can contact the author at :
     - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy
     - Public forum : https://groups.google.com/forum/#!forum/lz4c
 ****************************************************************** */
 #ifndef MEM_H_MODULE
 #define MEM_H_MODULE
 
 #if defined (__cplusplus)
 extern "C" {
 #endif
 
 /******************************************
 *  Includes
 ******************************************/
 #include     /* size_t, ptrdiff_t */
 #include     /* memcpy */
 
 
 /******************************************
 *  Compiler-specific
 ******************************************/
 #if defined(__GNUC__)
 #  define MEM_STATIC static __attribute__((unused))
 #elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
 #  define MEM_STATIC static inline
 #elif defined(_MSC_VER)
 #  define MEM_STATIC static __inline
 #else
 #  define MEM_STATIC static  /* this version may generate warnings for unused static functions; disable the relevant warning */
 #endif
 
 
 /****************************************************************
 *  Basic Types
 *****************************************************************/
 #if defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
 # include 
   typedef  uint8_t BYTE;
   typedef uint16_t U16;
   typedef  int16_t S16;
   typedef uint32_t U32;
   typedef  int32_t S32;
   typedef uint64_t U64;
   typedef  int64_t S64;
 #else
   typedef unsigned char       BYTE;
   typedef unsigned short      U16;
   typedef   signed short      S16;
   typedef unsigned int        U32;
   typedef   signed int        S32;
   typedef unsigned long long  U64;
   typedef   signed long long  S64;
 #endif
 
 
 /****************************************************************
 *  Memory I/O
 *****************************************************************/
 /* MEM_FORCE_MEMORY_ACCESS
  * By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable.
  * Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal.
  * The below switch allow to select different access method for improved performance.
  * Method 0 (default) : use `memcpy()`. Safe and portable.
  * Method 1 : `__packed` statement. It depends on compiler extension (ie, not portable).
  *            This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`.
  * Method 2 : direct access. This method is portable but violate C standard.
  *            It can generate buggy code on targets generating assembly depending on alignment.
  *            But in some circumstances, it's the only known way to get the most performance (ie GCC + ARMv6)
  * See http://fastcompression.blogspot.fr/2015/08/accessing-unaligned-memory.html for details.
  * Prefer these methods in priority order (0 > 1 > 2)
  */
 #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
 #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
 #    define MEM_FORCE_MEMORY_ACCESS 2
 #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) ))
 #    define MEM_FORCE_MEMORY_ACCESS 1
 #  endif
 #endif
 
 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(void*)==4; }
 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(void*)==8; }
 
 MEM_STATIC unsigned MEM_isLittleEndian(void)
 {
     const union { U32 u; BYTE c[4]; } one = { 1 };   /* don't use static : performance detrimental  */
     return one.c[0];
 }
 
 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2)
 
 /* violates C standard on structure alignment.
 Only use if no other choice to achieve best performance on target platform */
 MEM_STATIC U16 MEM_read16(const void* memPtr) { return *(const U16*) memPtr; }
 MEM_STATIC U32 MEM_read32(const void* memPtr) { return *(const U32*) memPtr; }
 MEM_STATIC U64 MEM_read64(const void* memPtr) { return *(const U64*) memPtr; }
 
 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; }
 
 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1)
 
 /* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
 /* currently only defined for gcc and icc */
 typedef union { U16 u16; U32 u32; U64 u64; } __attribute__((packed)) unalign;
 
 MEM_STATIC U16 MEM_read16(const void* ptr) { return ((const unalign*)ptr)->u16; }
 MEM_STATIC U32 MEM_read32(const void* ptr) { return ((const unalign*)ptr)->u32; }
 MEM_STATIC U64 MEM_read64(const void* ptr) { return ((const unalign*)ptr)->u64; }
 
 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { ((unalign*)memPtr)->u16 = value; }
 
 #else
 
 /* default method, safe and standard.
    can sometimes prove slower */
 
 MEM_STATIC U16 MEM_read16(const void* memPtr)
 {
     U16 val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
 MEM_STATIC U32 MEM_read32(const void* memPtr)
 {
     U32 val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
 MEM_STATIC U64 MEM_read64(const void* memPtr)
 {
     U64 val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
 MEM_STATIC void MEM_write16(void* memPtr, U16 value)
 {
     memcpy(memPtr, &value, sizeof(value));
 }
 
 #endif // MEM_FORCE_MEMORY_ACCESS
 
 
 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
 {
     if (MEM_isLittleEndian())
         return MEM_read16(memPtr);
     else
     {
         const BYTE* p = (const BYTE*)memPtr;
         return (U16)(p[0] + (p[1]<<8));
     }
 }
 
 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val)
 {
     if (MEM_isLittleEndian())
     {
         MEM_write16(memPtr, val);
     }
     else
     {
         BYTE* p = (BYTE*)memPtr;
         p[0] = (BYTE)val;
         p[1] = (BYTE)(val>>8);
     }
 }
 
 MEM_STATIC U32 MEM_readLE32(const void* memPtr)
 {
     if (MEM_isLittleEndian())
         return MEM_read32(memPtr);
     else
     {
         const BYTE* p = (const BYTE*)memPtr;
         return (U32)((U32)p[0] + ((U32)p[1]<<8) + ((U32)p[2]<<16) + ((U32)p[3]<<24));
     }
 }
 
 
 MEM_STATIC U64 MEM_readLE64(const void* memPtr)
 {
     if (MEM_isLittleEndian())
         return MEM_read64(memPtr);
     else
     {
         const BYTE* p = (const BYTE*)memPtr;
         return (U64)((U64)p[0] + ((U64)p[1]<<8) + ((U64)p[2]<<16) + ((U64)p[3]<<24)
                      + ((U64)p[4]<<32) + ((U64)p[5]<<40) + ((U64)p[6]<<48) + ((U64)p[7]<<56));
     }
 }
 
 
 MEM_STATIC size_t MEM_readLEST(const void* memPtr)
 {
     if (MEM_32bits())
         return (size_t)MEM_readLE32(memPtr);
     else
         return (size_t)MEM_readLE64(memPtr);
 }
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif /* MEM_H_MODULE */
 
 
 /* ******************************************************************
    bitstream
    Part of NewGen Entropy library
    header file (to include)
    Copyright (C) 2013-2015, Yann Collet.
 
    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:
 
        * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following disclaimer
    in the documentation and/or other materials provided with the
    distribution.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
    You can contact the author at :
    - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
    - Public forum : https://groups.google.com/forum/#!forum/lz4c
 ****************************************************************** */
 #ifndef BITSTREAM_H_MODULE
 #define BITSTREAM_H_MODULE
 
 #if defined (__cplusplus)
 extern "C" {
 #endif
 
 
 /*
 *  This API consists of small unitary functions, which highly benefit from being inlined.
 *  Since link-time-optimization is not available for all compilers,
 *  these functions are defined into a .h to be included.
 */
 
 
 /**********************************************
 *  bitStream decompression API (read backward)
 **********************************************/
 typedef struct
 {
     size_t   bitContainer;
     unsigned bitsConsumed;
     const char* ptr;
     const char* start;
 } BIT_DStream_t;
 
 typedef enum { BIT_DStream_unfinished = 0,
                BIT_DStream_endOfBuffer = 1,
                BIT_DStream_completed = 2,
                BIT_DStream_overflow = 3 } BIT_DStream_status;  /* result of BIT_reloadDStream() */
                /* 1,2,4,8 would be better for bitmap combinations, but slows down performance a bit ... :( */
 
 MEM_STATIC size_t   BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize);
 MEM_STATIC size_t   BIT_readBits(BIT_DStream_t* bitD, unsigned nbBits);
 MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD);
 MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* bitD);
 
 
-/*
-* Start by invoking BIT_initDStream().
-* A chunk of the bitStream is then stored into a local register.
-* Local register size is 64-bits on 64-bits systems, 32-bits on 32-bits systems (size_t).
-* You can then retrieve bitFields stored into the local register, **in reverse order**.
-* Local register is manually filled from memory by the BIT_reloadDStream() method.
-* A reload guarantee a minimum of ((8*sizeof(size_t))-7) bits when its result is BIT_DStream_unfinished.
-* Otherwise, it can be less than that, so proceed accordingly.
-* Checking if DStream has reached its end can be performed with BIT_endOfDStream()
-*/
-
-
 /******************************************
 *  unsafe API
 ******************************************/
 MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, unsigned nbBits);
 /* faster, but works only if nbBits >= 1 */
 
 
 
 /****************************************************************
 *  Helper functions
 ****************************************************************/
-MEM_STATIC unsigned BIT_highbit32 (register U32 val)
+MEM_STATIC unsigned BIT_highbit32 (U32 val)
 {
 #   if defined(_MSC_VER)   /* Visual */
     unsigned long r=0;
     _BitScanReverse ( &r, val );
     return (unsigned) r;
 #   elif defined(__GNUC__) && (__GNUC__ >= 3)   /* Use GCC Intrinsic */
     return 31 - __builtin_clz (val);
 #   else   /* Software version */
     static const unsigned DeBruijnClz[32] = { 0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30, 8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31 };
     U32 v = val;
     unsigned r;
     v |= v >> 1;
     v |= v >> 2;
     v |= v >> 4;
     v |= v >> 8;
     v |= v >> 16;
     r = DeBruijnClz[ (U32) (v * 0x07C4ACDDU) >> 27];
     return r;
 #   endif
 }
 
 
 
 /**********************************************************
 * bitStream decoding
 **********************************************************/
 
 /*!BIT_initDStream
 *  Initialize a BIT_DStream_t.
 *  @bitD : a pointer to an already allocated BIT_DStream_t structure
 *  @srcBuffer must point at the beginning of a bitStream
 *  @srcSize must be the exact size of the bitStream
 *  @result : size of stream (== srcSize) or an errorCode if a problem is detected
 */
 MEM_STATIC size_t BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize)
 {
     if (srcSize < 1) { memset(bitD, 0, sizeof(*bitD)); return ERROR(srcSize_wrong); }
 
     if (srcSize >=  sizeof(size_t))   /* normal case */
     {
         U32 contain32;
         bitD->start = (const char*)srcBuffer;
         bitD->ptr   = (const char*)srcBuffer + srcSize - sizeof(size_t);
         bitD->bitContainer = MEM_readLEST(bitD->ptr);
         contain32 = ((const BYTE*)srcBuffer)[srcSize-1];
         if (contain32 == 0) return ERROR(GENERIC);   /* endMark not present */
         bitD->bitsConsumed = 8 - BIT_highbit32(contain32);
     }
     else
     {
         U32 contain32;
         bitD->start = (const char*)srcBuffer;
         bitD->ptr   = bitD->start;
         bitD->bitContainer = *(const BYTE*)(bitD->start);
         switch(srcSize)
         {
             case 7: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[6]) << (sizeof(size_t)*8 - 16);
             case 6: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[5]) << (sizeof(size_t)*8 - 24);
             case 5: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[4]) << (sizeof(size_t)*8 - 32);
             case 4: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[3]) << 24;
             case 3: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[2]) << 16;
             case 2: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[1]) <<  8;
             default:;
         }
         contain32 = ((const BYTE*)srcBuffer)[srcSize-1];
         if (contain32 == 0) return ERROR(GENERIC);   /* endMark not present */
         bitD->bitsConsumed = 8 - BIT_highbit32(contain32);
         bitD->bitsConsumed += (U32)(sizeof(size_t) - srcSize)*8;
     }
 
     return srcSize;
 }
 
-/*!BIT_lookBits
- * Provides next n bits from local register
- * local register is not modified (bits are still present for next read/look)
- * On 32-bits, maxNbBits==25
- * On 64-bits, maxNbBits==57
- * @return : value extracted
- */
 MEM_STATIC size_t BIT_lookBits(BIT_DStream_t* bitD, U32 nbBits)
 {
     const U32 bitMask = sizeof(bitD->bitContainer)*8 - 1;
     return ((bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> 1) >> ((bitMask-nbBits) & bitMask);
 }
 
 /*! BIT_lookBitsFast :
 *   unsafe version; only works only if nbBits >= 1 */
 MEM_STATIC size_t BIT_lookBitsFast(BIT_DStream_t* bitD, U32 nbBits)
 {
     const U32 bitMask = sizeof(bitD->bitContainer)*8 - 1;
     return (bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> (((bitMask+1)-nbBits) & bitMask);
 }
 
 MEM_STATIC void BIT_skipBits(BIT_DStream_t* bitD, U32 nbBits)
 {
     bitD->bitsConsumed += nbBits;
 }
 
-/*!BIT_readBits
- * Read next n bits from local register.
- * pay attention to not read more than nbBits contained into local register.
- * @return : extracted value.
- */
 MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, U32 nbBits)
 {
     size_t value = BIT_lookBits(bitD, nbBits);
     BIT_skipBits(bitD, nbBits);
     return value;
 }
 
 /*!BIT_readBitsFast :
 *  unsafe version; only works only if nbBits >= 1 */
 MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, U32 nbBits)
 {
     size_t value = BIT_lookBitsFast(bitD, nbBits);
     BIT_skipBits(bitD, nbBits);
     return value;
 }
 
 MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD)
 {
     if (bitD->bitsConsumed > (sizeof(bitD->bitContainer)*8))  /* should never happen */
         return BIT_DStream_overflow;
 
     if (bitD->ptr >= bitD->start + sizeof(bitD->bitContainer))
     {
         bitD->ptr -= bitD->bitsConsumed >> 3;
         bitD->bitsConsumed &= 7;
         bitD->bitContainer = MEM_readLEST(bitD->ptr);
         return BIT_DStream_unfinished;
     }
     if (bitD->ptr == bitD->start)
     {
         if (bitD->bitsConsumed < sizeof(bitD->bitContainer)*8) return BIT_DStream_endOfBuffer;
         return BIT_DStream_completed;
     }
     {
         U32 nbBytes = bitD->bitsConsumed >> 3;
         BIT_DStream_status result = BIT_DStream_unfinished;
         if (bitD->ptr - nbBytes < bitD->start)
         {
             nbBytes = (U32)(bitD->ptr - bitD->start);  /* ptr > start */
             result = BIT_DStream_endOfBuffer;
         }
         bitD->ptr -= nbBytes;
         bitD->bitsConsumed -= nbBytes*8;
         bitD->bitContainer = MEM_readLEST(bitD->ptr);   /* reminder : srcSize > sizeof(bitD) */
         return result;
     }
 }
 
 /*! BIT_endOfDStream
 *   @return Tells if DStream has reached its exact end
 */
 MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* DStream)
 {
     return ((DStream->ptr == DStream->start) && (DStream->bitsConsumed == sizeof(DStream->bitContainer)*8));
 }
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif /* BITSTREAM_H_MODULE */
 /* ******************************************************************
    Error codes and messages
    Copyright (C) 2013-2015, Yann Collet
 
    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:
 
        * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following disclaimer
    in the documentation and/or other materials provided with the
    distribution.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
    You can contact the author at :
    - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
    - Public forum : https://groups.google.com/forum/#!forum/lz4c
 ****************************************************************** */
 #ifndef ERROR_H_MODULE
 #define ERROR_H_MODULE
 
 #if defined (__cplusplus)
 extern "C" {
 #endif
 
 
 /******************************************
 *  Compiler-specific
 ******************************************/
 #if defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
 #  define ERR_STATIC static inline
 #elif defined(_MSC_VER)
 #  define ERR_STATIC static __inline
 #elif defined(__GNUC__)
 #  define ERR_STATIC static __attribute__((unused))
 #else
 #  define ERR_STATIC static  /* this version may generate warnings for unused static functions; disable the relevant warning */
 #endif
 
 
 /******************************************
 *  Error Management
 ******************************************/
 #define PREFIX(name) ZSTD_error_##name
 
 #define ERROR(name) (size_t)-PREFIX(name)
 
 #define ERROR_LIST(ITEM) \
         ITEM(PREFIX(No_Error)) ITEM(PREFIX(GENERIC)) \
         ITEM(PREFIX(dstSize_tooSmall)) ITEM(PREFIX(srcSize_wrong)) \
         ITEM(PREFIX(prefix_unknown)) ITEM(PREFIX(corruption_detected)) \
         ITEM(PREFIX(tableLog_tooLarge)) ITEM(PREFIX(maxSymbolValue_tooLarge)) ITEM(PREFIX(maxSymbolValue_tooSmall)) \
         ITEM(PREFIX(maxCode))
 
 #define ERROR_GENERATE_ENUM(ENUM) ENUM,
 typedef enum { ERROR_LIST(ERROR_GENERATE_ENUM) } ERR_codes;  /* enum is exposed, to detect & handle specific errors; compare function result to -enum value */
 
 #define ERROR_CONVERTTOSTRING(STRING) #STRING,
 #define ERROR_GENERATE_STRING(EXPR) ERROR_CONVERTTOSTRING(EXPR)
 static const char* ERR_strings[] = { ERROR_LIST(ERROR_GENERATE_STRING) };
 
 ERR_STATIC unsigned ERR_isError(size_t code) { return (code > ERROR(maxCode)); }
 
 ERR_STATIC const char* ERR_getErrorName(size_t code)
 {
     static const char* codeError = "Unspecified error code";
     if (ERR_isError(code)) return ERR_strings[-(int)(code)];
     return codeError;
 }
 
 
 #if defined (__cplusplus)
 }
 #endif
 
 #endif /* ERROR_H_MODULE */
 /*
 Constructor and Destructor of type FSE_CTable
     Note that its size depends on 'tableLog' and 'maxSymbolValue' */
 typedef unsigned FSE_CTable;   /* don't allocate that. It's just a way to be more restrictive than void* */
 typedef unsigned FSE_DTable;   /* don't allocate that. It's just a way to be more restrictive than void* */
 
 
 /* ******************************************************************
    FSE : Finite State Entropy coder
    header file for static linking (only)
    Copyright (C) 2013-2015, Yann Collet
 
    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:
 
        * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following disclaimer
    in the documentation and/or other materials provided with the
    distribution.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
    You can contact the author at :
    - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
    - Public forum : https://groups.google.com/forum/#!forum/lz4c
 ****************************************************************** */
 #if defined (__cplusplus)
 extern "C" {
 #endif
 
 
 /******************************************
 *  Static allocation
 ******************************************/
 /* FSE buffer bounds */
 #define FSE_NCOUNTBOUND 512
 #define FSE_BLOCKBOUND(size) (size + (size>>7))
 #define FSE_COMPRESSBOUND(size) (FSE_NCOUNTBOUND + FSE_BLOCKBOUND(size))   /* Macro version, useful for static allocation */
 
 /* You can statically allocate FSE CTable/DTable as a table of unsigned using below macro */
 #define FSE_CTABLE_SIZE_U32(maxTableLog, maxSymbolValue)   (1 + (1<<(maxTableLog-1)) + ((maxSymbolValue+1)*2))
 #define FSE_DTABLE_SIZE_U32(maxTableLog)                   (1 + (1<= BIT_DStream_completed
-
-When it's done, verify decompression is fully completed, by checking both DStream and the relevant states.
-Checking if DStream has reached its end is performed by :
-    BIT_endOfDStream(&DStream);
-Check also the states. There might be some symbols left there, if some high probability ones (>50%) are possible.
-    FSE_endOfDState(&DState);
-*/
 
 
 /******************************************
 *  FSE unsafe API
 ******************************************/
 static unsigned char FSE_decodeSymbolFast(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD);
 /* faster, but works only if nbBits is always >= 1 (otherwise, result will be corrupted) */
 
 
 /******************************************
 *  Implementation of inline functions
 ******************************************/
 
 /* decompression */
 
 typedef struct {
     U16 tableLog;
     U16 fastMode;
 } FSE_DTableHeader;   /* sizeof U32 */
 
 typedef struct
 {
     unsigned short newState;
     unsigned char  symbol;
     unsigned char  nbBits;
 } FSE_decode_t;   /* size == U32 */
 
 MEM_STATIC void FSE_initDState(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD, const FSE_DTable* dt)
 {
     FSE_DTableHeader DTableH;
     memcpy(&DTableH, dt, sizeof(DTableH));
     DStatePtr->state = BIT_readBits(bitD, DTableH.tableLog);
     BIT_reloadDStream(bitD);
     DStatePtr->table = dt + 1;
 }
 
 MEM_STATIC BYTE FSE_decodeSymbol(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD)
 {
     const FSE_decode_t DInfo = ((const FSE_decode_t*)(DStatePtr->table))[DStatePtr->state];
     const U32  nbBits = DInfo.nbBits;
     BYTE symbol = DInfo.symbol;
     size_t lowBits = BIT_readBits(bitD, nbBits);
 
     DStatePtr->state = DInfo.newState + lowBits;
     return symbol;
 }
 
 MEM_STATIC BYTE FSE_decodeSymbolFast(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD)
 {
     const FSE_decode_t DInfo = ((const FSE_decode_t*)(DStatePtr->table))[DStatePtr->state];
     const U32 nbBits = DInfo.nbBits;
     BYTE symbol = DInfo.symbol;
     size_t lowBits = BIT_readBitsFast(bitD, nbBits);
 
     DStatePtr->state = DInfo.newState + lowBits;
     return symbol;
 }
 
 MEM_STATIC unsigned FSE_endOfDState(const FSE_DState_t* DStatePtr)
 {
     return DStatePtr->state == 0;
 }
 
 
 #if defined (__cplusplus)
 }
 #endif
 /* ******************************************************************
    Huff0 : Huffman coder, part of New Generation Entropy library
    header file for static linking (only)
    Copyright (C) 2013-2015, Yann Collet
 
    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:
 
        * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following disclaimer
    in the documentation and/or other materials provided with the
    distribution.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
    You can contact the author at :
    - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
    - Public forum : https://groups.google.com/forum/#!forum/lz4c
 ****************************************************************** */
 
 #if defined (__cplusplus)
 extern "C" {
 #endif
 
 /******************************************
 *  Static allocation macros
 ******************************************/
 /* Huff0 buffer bounds */
 #define HUF_CTABLEBOUND 129
 #define HUF_BLOCKBOUND(size) (size + (size>>8) + 8)   /* only true if incompressible pre-filtered with fast heuristic */
 #define HUF_COMPRESSBOUND(size) (HUF_CTABLEBOUND + HUF_BLOCKBOUND(size))   /* Macro version, useful for static allocation */
 
 /* static allocation of Huff0's DTable */
 #define HUF_DTABLE_SIZE(maxTableLog)   (1 + (1<   /* size_t */
 
 
 /* *************************************
 *  Version
 ***************************************/
 #define ZSTD_VERSION_MAJOR    0    /* for breaking interface changes  */
 #define ZSTD_VERSION_MINOR    2    /* for new (non-breaking) interface capabilities */
 #define ZSTD_VERSION_RELEASE  2    /* for tweaks, bug-fixes, or development */
 #define ZSTD_VERSION_NUMBER  (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)
 
 
 /* *************************************
 *  Advanced functions
 ***************************************/
 typedef struct ZSTD_CCtx_s ZSTD_CCtx;   /* incomplete type */
 
 #if defined (__cplusplus)
 }
 #endif
 /*
     zstd - standard compression library
     Header File for static linking only
     Copyright (C) 2014-2015, Yann Collet.
 
     BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions are
     met:
     * Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
     * Redistributions in binary form must reproduce the above
     copyright notice, this list of conditions and the following disclaimer
     in the documentation and/or other materials provided with the
     distribution.
     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
     You can contact the author at :
     - zstd source repository : https://github.com/Cyan4973/zstd
     - ztsd public forum : https://groups.google.com/forum/#!forum/lz4c
 */
 
 /* The objects defined into this file should be considered experimental.
  * They are not labelled stable, as their prototype may change in the future.
  * You can use them for tests, provide feedback, or if you can endure risk of future changes.
  */
 
 #if defined (__cplusplus)
 extern "C" {
 #endif
 
 /* *************************************
 *  Streaming functions
 ***************************************/
 
 typedef struct ZSTD_DCtx_s ZSTD_DCtx;
 
 /*
   Use above functions alternatively.
   ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
   ZSTD_decompressContinue() will use previous data blocks to improve compression if they are located prior to current block.
   Result is the number of bytes regenerated within 'dst'.
   It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
 */
 
 /* *************************************
 *  Prefix - version detection
 ***************************************/
 #define ZSTD_magicNumber 0xFD2FB522   /* v0.2 (current)*/
 
 
 #if defined (__cplusplus)
 }
 #endif
 /* ******************************************************************
    FSE : Finite State Entropy coder
    Copyright (C) 2013-2015, Yann Collet.
 
    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:
 
        * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following disclaimer
    in the documentation and/or other materials provided with the
    distribution.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
     You can contact the author at :
     - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy
     - Public forum : https://groups.google.com/forum/#!forum/lz4c
 ****************************************************************** */
 
 #ifndef FSE_COMMONDEFS_ONLY
 
 /****************************************************************
 *  Tuning parameters
 ****************************************************************/
 /* MEMORY_USAGE :
 *  Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
 *  Increasing memory usage improves compression ratio
 *  Reduced memory usage can improve speed, due to cache effect
 *  Recommended max value is 14, for 16KB, which nicely fits into Intel x86 L1 cache */
 #define FSE_MAX_MEMORY_USAGE 14
 #define FSE_DEFAULT_MEMORY_USAGE 13
 
 /* FSE_MAX_SYMBOL_VALUE :
 *  Maximum symbol value authorized.
 *  Required for proper stack allocation */
 #define FSE_MAX_SYMBOL_VALUE 255
 
 
 /****************************************************************
 *  template functions type & suffix
 ****************************************************************/
 #define FSE_FUNCTION_TYPE BYTE
 #define FSE_FUNCTION_EXTENSION
 
 
 /****************************************************************
 *  Byte symbol type
 ****************************************************************/
 #endif   /* !FSE_COMMONDEFS_ONLY */
 
 
 /****************************************************************
 *  Compiler specifics
 ****************************************************************/
 #ifdef _MSC_VER    /* Visual Studio */
 #  define FORCE_INLINE static __forceinline
 #  include                     /* For Visual 2005 */
 #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
 #  pragma warning(disable : 4214)        /* disable: C4214: non-int bitfields */
 #else
 #  if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
 #    ifdef __GNUC__
 #      define FORCE_INLINE static inline __attribute__((always_inline))
 #    else
 #      define FORCE_INLINE static inline
 #    endif
 #  else
 #    define FORCE_INLINE static
 #  endif /* __STDC_VERSION__ */
 #endif
 
 
 /****************************************************************
 *  Includes
 ****************************************************************/
 #include      /* malloc, free, qsort */
 #include      /* memcpy, memset */
 #include       /* printf (debug) */
 
 /****************************************************************
 *  Constants
 *****************************************************************/
 #define FSE_MAX_TABLELOG  (FSE_MAX_MEMORY_USAGE-2)
 #define FSE_MAX_TABLESIZE (1U< FSE_TABLELOG_ABSOLUTE_MAX
 #error "FSE_MAX_TABLELOG > FSE_TABLELOG_ABSOLUTE_MAX is not supported"
 #endif
 
 
 /****************************************************************
 *  Error Management
 ****************************************************************/
 #define FSE_STATIC_ASSERT(c) { enum { FSE_static_assert = 1/(int)(!!(c)) }; }   /* use only *after* variable declarations */
 
 
 /****************************************************************
 *  Complex types
 ****************************************************************/
 typedef U32 DTable_max_t[FSE_DTABLE_SIZE_U32(FSE_MAX_TABLELOG)];
 
 
 /****************************************************************
 *  Templates
 ****************************************************************/
 /*
   designed to be included
   for type-specific functions (template emulation in C)
   Objective is to write these functions only once, for improved maintenance
 */
 
 /* safety checks */
 #ifndef FSE_FUNCTION_EXTENSION
 #  error "FSE_FUNCTION_EXTENSION must be defined"
 #endif
 #ifndef FSE_FUNCTION_TYPE
 #  error "FSE_FUNCTION_TYPE must be defined"
 #endif
 
 /* Function names */
 #define FSE_CAT(X,Y) X##Y
 #define FSE_FUNCTION_NAME(X,Y) FSE_CAT(X,Y)
 #define FSE_TYPE_NAME(X,Y) FSE_CAT(X,Y)
 
 
 /* Function templates */
 
 #define FSE_DECODE_TYPE FSE_decode_t
 
 static U32 FSE_tableStep(U32 tableSize) { return (tableSize>>1) + (tableSize>>3) + 3; }
 
 static size_t FSE_buildDTable
 (FSE_DTable* dt, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog)
 {
     void* ptr = dt+1;
     FSE_DECODE_TYPE* const tableDecode = (FSE_DECODE_TYPE*)ptr;
     FSE_DTableHeader DTableH;
     const U32 tableSize = 1 << tableLog;
     const U32 tableMask = tableSize-1;
     const U32 step = FSE_tableStep(tableSize);
     U16 symbolNext[FSE_MAX_SYMBOL_VALUE+1];
     U32 position = 0;
     U32 highThreshold = tableSize-1;
     const S16 largeLimit= (S16)(1 << (tableLog-1));
     U32 noLarge = 1;
     U32 s;
 
     /* Sanity Checks */
     if (maxSymbolValue > FSE_MAX_SYMBOL_VALUE) return ERROR(maxSymbolValue_tooLarge);
     if (tableLog > FSE_MAX_TABLELOG) return ERROR(tableLog_tooLarge);
 
     /* Init, lay down lowprob symbols */
     DTableH.tableLog = (U16)tableLog;
     for (s=0; s<=maxSymbolValue; s++)
     {
         if (normalizedCounter[s]==-1)
         {
             tableDecode[highThreshold--].symbol = (FSE_FUNCTION_TYPE)s;
             symbolNext[s] = 1;
         }
         else
         {
             if (normalizedCounter[s] >= largeLimit) noLarge=0;
             symbolNext[s] = normalizedCounter[s];
         }
     }
 
     /* Spread symbols */
     for (s=0; s<=maxSymbolValue; s++)
     {
         int i;
         for (i=0; i highThreshold) position = (position + step) & tableMask;   /* lowprob area */
         }
     }
 
     if (position!=0) return ERROR(GENERIC);   /* position must reach all cells once, otherwise normalizedCounter is incorrect */
 
     /* Build Decoding table */
     {
         U32 i;
         for (i=0; i FSE_TABLELOG_ABSOLUTE_MAX) return ERROR(tableLog_tooLarge);
     bitStream >>= 4;
     bitCount = 4;
     *tableLogPtr = nbBits;
     remaining = (1<1) && (charnum<=*maxSVPtr))
     {
         if (previous0)
         {
             unsigned n0 = charnum;
             while ((bitStream & 0xFFFF) == 0xFFFF)
             {
                 n0+=24;
                 if (ip < iend-5)
                 {
                     ip+=2;
                     bitStream = MEM_readLE32(ip) >> bitCount;
                 }
                 else
                 {
                     bitStream >>= 16;
                     bitCount+=16;
                 }
             }
             while ((bitStream & 3) == 3)
             {
                 n0+=3;
                 bitStream>>=2;
                 bitCount+=2;
             }
             n0 += bitStream & 3;
             bitCount += 2;
             if (n0 > *maxSVPtr) return ERROR(maxSymbolValue_tooSmall);
             while (charnum < n0) normalizedCounter[charnum++] = 0;
             if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4))
             {
                 ip += bitCount>>3;
                 bitCount &= 7;
                 bitStream = MEM_readLE32(ip) >> bitCount;
             }
             else
                 bitStream >>= 2;
         }
         {
             const short max = (short)((2*threshold-1)-remaining);
             short count;
 
             if ((bitStream & (threshold-1)) < (U32)max)
             {
                 count = (short)(bitStream & (threshold-1));
                 bitCount   += nbBits-1;
             }
             else
             {
                 count = (short)(bitStream & (2*threshold-1));
                 if (count >= threshold) count -= max;
                 bitCount   += nbBits;
             }
 
             count--;   /* extra accuracy */
             remaining -= FSE_abs(count);
             normalizedCounter[charnum++] = count;
             previous0 = !count;
             while (remaining < threshold)
             {
                 nbBits--;
                 threshold >>= 1;
             }
 
             {
                 if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4))
                 {
                     ip += bitCount>>3;
                     bitCount &= 7;
                 }
                 else
                 {
                     bitCount -= (int)(8 * (iend - 4 - ip));
                     ip = iend - 4;
                 }
                 bitStream = MEM_readLE32(ip) >> (bitCount & 31);
             }
         }
     }
     if (remaining != 1) return ERROR(GENERIC);
     *maxSVPtr = charnum-1;
 
     ip += (bitCount+7)>>3;
     if ((size_t)(ip-istart) > hbSize) return ERROR(srcSize_wrong);
     return ip-istart;
 }
 
 
 /*********************************************************
 *  Decompression (Byte symbols)
 *********************************************************/
 static size_t FSE_buildDTable_rle (FSE_DTable* dt, BYTE symbolValue)
 {
     void* ptr = dt;
     FSE_DTableHeader* const DTableH = (FSE_DTableHeader*)ptr;
     FSE_decode_t* const cell = (FSE_decode_t*)(ptr) + 1;   /* because dt is unsigned */
 
     DTableH->tableLog = 0;
     DTableH->fastMode = 0;
 
     cell->newState = 0;
     cell->symbol = symbolValue;
     cell->nbBits = 0;
 
     return 0;
 }
 
 
 static size_t FSE_buildDTable_raw (FSE_DTable* dt, unsigned nbBits)
 {
     void* ptr = dt;
     FSE_DTableHeader* const DTableH = (FSE_DTableHeader*)ptr;
     FSE_decode_t* const dinfo = (FSE_decode_t*)(ptr) + 1;   /* because dt is unsigned */
     const unsigned tableSize = 1 << nbBits;
     const unsigned tableMask = tableSize - 1;
     const unsigned maxSymbolValue = tableMask;
     unsigned s;
 
     /* Sanity checks */
     if (nbBits < 1) return ERROR(GENERIC);         /* min size */
 
     /* Build Decoding Table */
     DTableH->tableLog = (U16)nbBits;
     DTableH->fastMode = 1;
     for (s=0; s<=maxSymbolValue; s++)
     {
         dinfo[s].newState = 0;
         dinfo[s].symbol = (BYTE)s;
         dinfo[s].nbBits = (BYTE)nbBits;
     }
 
     return 0;
 }
 
 FORCE_INLINE size_t FSE_decompress_usingDTable_generic(
           void* dst, size_t maxDstSize,
     const void* cSrc, size_t cSrcSize,
     const FSE_DTable* dt, const unsigned fast)
 {
     BYTE* const ostart = (BYTE*) dst;
     BYTE* op = ostart;
     BYTE* const omax = op + maxDstSize;
     BYTE* const olimit = omax-3;
 
     BIT_DStream_t bitD;
     FSE_DState_t state1;
     FSE_DState_t state2;
     size_t errorCode;
 
     /* Init */
     errorCode = BIT_initDStream(&bitD, cSrc, cSrcSize);   /* replaced last arg by maxCompressed Size */
     if (FSE_isError(errorCode)) return errorCode;
 
     FSE_initDState(&state1, &bitD, dt);
     FSE_initDState(&state2, &bitD, dt);
 
 #define FSE_GETSYMBOL(statePtr) fast ? FSE_decodeSymbolFast(statePtr, &bitD) : FSE_decodeSymbol(statePtr, &bitD)
 
     /* 4 symbols per loop */
     for ( ; (BIT_reloadDStream(&bitD)==BIT_DStream_unfinished) && (op sizeof(bitD.bitContainer)*8)    /* This test must be static */
             BIT_reloadDStream(&bitD);
 
         op[1] = FSE_GETSYMBOL(&state2);
 
         if (FSE_MAX_TABLELOG*4+7 > sizeof(bitD.bitContainer)*8)    /* This test must be static */
             { if (BIT_reloadDStream(&bitD) > BIT_DStream_unfinished) { op+=2; break; } }
 
         op[2] = FSE_GETSYMBOL(&state1);
 
         if (FSE_MAX_TABLELOG*2+7 > sizeof(bitD.bitContainer)*8)    /* This test must be static */
             BIT_reloadDStream(&bitD);
 
         op[3] = FSE_GETSYMBOL(&state2);
     }
 
     /* tail */
     /* note : BIT_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends at exactly BIT_DStream_completed */
     while (1)
     {
         if ( (BIT_reloadDStream(&bitD)>BIT_DStream_completed) || (op==omax) || (BIT_endOfDStream(&bitD) && (fast || FSE_endOfDState(&state1))) )
             break;
 
         *op++ = FSE_GETSYMBOL(&state1);
 
         if ( (BIT_reloadDStream(&bitD)>BIT_DStream_completed) || (op==omax) || (BIT_endOfDStream(&bitD) && (fast || FSE_endOfDState(&state2))) )
             break;
 
         *op++ = FSE_GETSYMBOL(&state2);
     }
 
     /* end ? */
     if (BIT_endOfDStream(&bitD) && FSE_endOfDState(&state1) && FSE_endOfDState(&state2))
         return op-ostart;
 
     if (op==omax) return ERROR(dstSize_tooSmall);   /* dst buffer is full, but cSrc unfinished */
 
     return ERROR(corruption_detected);
 }
 
 
 static size_t FSE_decompress_usingDTable(void* dst, size_t originalSize,
                             const void* cSrc, size_t cSrcSize,
                             const FSE_DTable* dt)
 {
     FSE_DTableHeader DTableH;
     memcpy(&DTableH, dt, sizeof(DTableH));
 
     /* select fast mode (static) */
     if (DTableH.fastMode) return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 1);
     return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 0);
 }
 
 
 static size_t FSE_decompress(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize)
 {
     const BYTE* const istart = (const BYTE*)cSrc;
     const BYTE* ip = istart;
     short counting[FSE_MAX_SYMBOL_VALUE+1];
     DTable_max_t dt;   /* Static analyzer seems unable to understand this table will be properly initialized later */
     unsigned tableLog;
     unsigned maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
     size_t errorCode;
 
     if (cSrcSize<2) return ERROR(srcSize_wrong);   /* too small input size */
 
     /* normal FSE decoding mode */
     errorCode = FSE_readNCount (counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
     if (FSE_isError(errorCode)) return errorCode;
     if (errorCode >= cSrcSize) return ERROR(srcSize_wrong);   /* too small input size */
     ip += errorCode;
     cSrcSize -= errorCode;
 
     errorCode = FSE_buildDTable (dt, counting, maxSymbolValue, tableLog);
     if (FSE_isError(errorCode)) return errorCode;
 
     /* always return, even if it is an error code */
     return FSE_decompress_usingDTable (dst, maxDstSize, ip, cSrcSize, dt);
 }
 
 
 
 #endif   /* FSE_COMMONDEFS_ONLY */
 /* ******************************************************************
    Huff0 : Huffman coder, part of New Generation Entropy library
    Copyright (C) 2013-2015, Yann Collet.
 
    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:
 
        * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following disclaimer
    in the documentation and/or other materials provided with the
    distribution.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
     You can contact the author at :
     - FSE+Huff0 source repository : https://github.com/Cyan4973/FiniteStateEntropy
     - Public forum : https://groups.google.com/forum/#!forum/lz4c
 ****************************************************************** */
 
 /****************************************************************
 *  Compiler specifics
 ****************************************************************/
 #if defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
 /* inline is defined */
 #elif defined(_MSC_VER)
 #  define inline __inline
 #else
 #  define inline /* disable inline */
 #endif
 
 
 #ifdef _MSC_VER    /* Visual Studio */
 #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
 #endif
 
 
 /****************************************************************
 *  Includes
 ****************************************************************/
 #include      /* malloc, free, qsort */
 #include      /* memcpy, memset */
 #include       /* printf (debug) */
 
 /****************************************************************
 *  Error Management
 ****************************************************************/
 #define HUF_STATIC_ASSERT(c) { enum { HUF_static_assert = 1/(int)(!!(c)) }; }   /* use only *after* variable declarations */
 
 
 /******************************************
 *  Helper functions
 ******************************************/
 static unsigned HUF_isError(size_t code) { return ERR_isError(code); }
 
 #define HUF_ABSOLUTEMAX_TABLELOG  16   /* absolute limit of HUF_MAX_TABLELOG. Beyond that value, code does not work */
 #define HUF_MAX_TABLELOG  12           /* max configured tableLog (for static allocation); can be modified up to HUF_ABSOLUTEMAX_TABLELOG */
 #define HUF_DEFAULT_TABLELOG  HUF_MAX_TABLELOG   /* tableLog by default, when not specified */
 #define HUF_MAX_SYMBOL_VALUE 255
 #if (HUF_MAX_TABLELOG > HUF_ABSOLUTEMAX_TABLELOG)
 #  error "HUF_MAX_TABLELOG is too large !"
 #endif
 
 
 
 /*********************************************************
 *  Huff0 : Huffman block decompression
 *********************************************************/
 typedef struct { BYTE byte; BYTE nbBits; } HUF_DEltX2;   /* single-symbol decoding */
 
 typedef struct { U16 sequence; BYTE nbBits; BYTE length; } HUF_DEltX4;  /* double-symbols decoding */
 
 typedef struct { BYTE symbol; BYTE weight; } sortedSymbol_t;
 
 /*! HUF_readStats
     Read compact Huffman tree, saved by HUF_writeCTable
     @huffWeight : destination buffer
     @return : size read from `src`
 */
 static size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
                             U32* nbSymbolsPtr, U32* tableLogPtr,
                             const void* src, size_t srcSize)
 {
     U32 weightTotal;
     U32 tableLog;
     const BYTE* ip = (const BYTE*) src;
     size_t iSize;
     size_t oSize;
     U32 n;
 
     if (!srcSize) return ERROR(srcSize_wrong);
     iSize = ip[0];
     //memset(huffWeight, 0, hwSize);   /* is not necessary, even though some analyzer complain ... */
 
     if (iSize >= 128)  /* special header */
     {
         if (iSize >= (242))   /* RLE */
         {
             static int l[14] = { 1, 2, 3, 4, 7, 8, 15, 16, 31, 32, 63, 64, 127, 128 };
             oSize = l[iSize-242];
             memset(huffWeight, 1, hwSize);
             iSize = 0;
         }
         else   /* Incompressible */
         {
             oSize = iSize - 127;
             iSize = ((oSize+1)/2);
             if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
             if (oSize >= hwSize) return ERROR(corruption_detected);
             ip += 1;
             for (n=0; n> 4;
                 huffWeight[n+1] = ip[n/2] & 15;
             }
         }
     }
     else  /* header compressed with FSE (normal case) */
     {
         if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
         oSize = FSE_decompress(huffWeight, hwSize-1, ip+1, iSize);   /* max (hwSize-1) values decoded, as last one is implied */
         if (FSE_isError(oSize)) return oSize;
     }
 
     /* collect weight stats */
     memset(rankStats, 0, (HUF_ABSOLUTEMAX_TABLELOG + 1) * sizeof(U32));
     weightTotal = 0;
     for (n=0; n= HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
         rankStats[huffWeight[n]]++;
         weightTotal += (1 << huffWeight[n]) >> 1;
     }
     if (weightTotal == 0) return ERROR(corruption_detected);
 
     /* get last non-null symbol weight (implied, total must be 2^n) */
     tableLog = BIT_highbit32(weightTotal) + 1;
     if (tableLog > HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
     {
         U32 total = 1 << tableLog;
         U32 rest = total - weightTotal;
         U32 verif = 1 << BIT_highbit32(rest);
         U32 lastWeight = BIT_highbit32(rest) + 1;
         if (verif != rest) return ERROR(corruption_detected);    /* last value must be a clean power of 2 */
         huffWeight[oSize] = (BYTE)lastWeight;
         rankStats[lastWeight]++;
     }
 
     /* check tree construction validity */
     if ((rankStats[1] < 2) || (rankStats[1] & 1)) return ERROR(corruption_detected);   /* by construction : at least 2 elts of rank 1, must be even */
 
     /* results */
     *nbSymbolsPtr = (U32)(oSize+1);
     *tableLogPtr = tableLog;
     return iSize+1;
 }
 
 
 /**************************/
 /* single-symbol decoding */
 /**************************/
 
 static size_t HUF_readDTableX2 (U16* DTable, const void* src, size_t srcSize)
 {
     BYTE huffWeight[HUF_MAX_SYMBOL_VALUE + 1];
     U32 rankVal[HUF_ABSOLUTEMAX_TABLELOG + 1];   /* large enough for values from 0 to 16 */
     U32 tableLog = 0;
     const BYTE* ip = (const BYTE*) src;
     size_t iSize = ip[0];
     U32 nbSymbols = 0;
     U32 n;
     U32 nextRankStart;
     void* ptr = DTable+1;
     HUF_DEltX2* const dt = (HUF_DEltX2*)ptr;
 
     HUF_STATIC_ASSERT(sizeof(HUF_DEltX2) == sizeof(U16));   /* if compilation fails here, assertion is false */
     //memset(huffWeight, 0, sizeof(huffWeight));   /* is not necessary, even though some analyzer complain ... */
 
     iSize = HUF_readStats(huffWeight, HUF_MAX_SYMBOL_VALUE + 1, rankVal, &nbSymbols, &tableLog, src, srcSize);
     if (HUF_isError(iSize)) return iSize;
 
     /* check result */
     if (tableLog > DTable[0]) return ERROR(tableLog_tooLarge);   /* DTable is too small */
     DTable[0] = (U16)tableLog;   /* maybe should separate sizeof DTable, as allocated, from used size of DTable, in case of DTable re-use */
 
     /* Prepare ranks */
     nextRankStart = 0;
     for (n=1; n<=tableLog; n++)
     {
         U32 current = nextRankStart;
         nextRankStart += (rankVal[n] << (n-1));
         rankVal[n] = current;
     }
 
     /* fill DTable */
     for (n=0; n> 1;
         U32 i;
         HUF_DEltX2 D;
         D.byte = (BYTE)n; D.nbBits = (BYTE)(tableLog + 1 - w);
         for (i = rankVal[w]; i < rankVal[w] + length; i++)
             dt[i] = D;
         rankVal[w] += length;
     }
 
     return iSize;
 }
 
 static BYTE HUF_decodeSymbolX2(BIT_DStream_t* Dstream, const HUF_DEltX2* dt, const U32 dtLog)
 {
         const size_t val = BIT_lookBitsFast(Dstream, dtLog); /* note : dtLog >= 1 */
         const BYTE c = dt[val].byte;
         BIT_skipBits(Dstream, dt[val].nbBits);
         return c;
 }
 
 #define HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr) \
     *ptr++ = HUF_decodeSymbolX2(DStreamPtr, dt, dtLog)
 
 #define HUF_DECODE_SYMBOLX2_1(ptr, DStreamPtr) \
     if (MEM_64bits() || (HUF_MAX_TABLELOG<=12)) \
         HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr)
 
 #define HUF_DECODE_SYMBOLX2_2(ptr, DStreamPtr) \
     if (MEM_64bits()) \
         HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr)
 
 static inline size_t HUF_decodeStreamX2(BYTE* p, BIT_DStream_t* const bitDPtr, BYTE* const pEnd, const HUF_DEltX2* const dt, const U32 dtLog)
 {
     BYTE* const pStart = p;
 
     /* up to 4 symbols at a time */
     while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p <= pEnd-4))
     {
         HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
         HUF_DECODE_SYMBOLX2_1(p, bitDPtr);
         HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
         HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
     }
 
     /* closer to the end */
     while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p < pEnd))
         HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
 
     /* no more data to retrieve from bitstream, hence no need to reload */
     while (p < pEnd)
         HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
 
     return pEnd-pStart;
 }
 
 
 static size_t HUF_decompress4X2_usingDTable(
           void* dst,  size_t dstSize,
     const void* cSrc, size_t cSrcSize,
     const U16* DTable)
 {
     if (cSrcSize < 10) return ERROR(corruption_detected);   /* strict minimum : jump table + 1 byte per stream */
 
     {
         const BYTE* const istart = (const BYTE*) cSrc;
         BYTE* const ostart = (BYTE*) dst;
         BYTE* const oend = ostart + dstSize;
 
         const void* ptr = DTable;
         const HUF_DEltX2* const dt = ((const HUF_DEltX2*)ptr) +1;
         const U32 dtLog = DTable[0];
         size_t errorCode;
 
         /* Init */
         BIT_DStream_t bitD1;
         BIT_DStream_t bitD2;
         BIT_DStream_t bitD3;
         BIT_DStream_t bitD4;
         const size_t length1 = MEM_readLE16(istart);
         const size_t length2 = MEM_readLE16(istart+2);
         const size_t length3 = MEM_readLE16(istart+4);
         size_t length4;
         const BYTE* const istart1 = istart + 6;  /* jumpTable */
         const BYTE* const istart2 = istart1 + length1;
         const BYTE* const istart3 = istart2 + length2;
         const BYTE* const istart4 = istart3 + length3;
         const size_t segmentSize = (dstSize+3) / 4;
         BYTE* const opStart2 = ostart + segmentSize;
         BYTE* const opStart3 = opStart2 + segmentSize;
         BYTE* const opStart4 = opStart3 + segmentSize;
         BYTE* op1 = ostart;
         BYTE* op2 = opStart2;
         BYTE* op3 = opStart3;
         BYTE* op4 = opStart4;
         U32 endSignal;
 
         length4 = cSrcSize - (length1 + length2 + length3 + 6);
         if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
         errorCode = BIT_initDStream(&bitD1, istart1, length1);
         if (HUF_isError(errorCode)) return errorCode;
         errorCode = BIT_initDStream(&bitD2, istart2, length2);
         if (HUF_isError(errorCode)) return errorCode;
         errorCode = BIT_initDStream(&bitD3, istart3, length3);
         if (HUF_isError(errorCode)) return errorCode;
         errorCode = BIT_initDStream(&bitD4, istart4, length4);
         if (HUF_isError(errorCode)) return errorCode;
 
         /* 16-32 symbols per loop (4-8 symbols per stream) */
         endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
         for ( ; (endSignal==BIT_DStream_unfinished) && (op4<(oend-7)) ; )
         {
             HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
             HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
             HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
             HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
             HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
             HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
             HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
             HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
             HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
             HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
             HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
             HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
             HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
             HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
             HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
             HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
 
             endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
         }
 
         /* check corruption */
         if (op1 > opStart2) return ERROR(corruption_detected);
         if (op2 > opStart3) return ERROR(corruption_detected);
         if (op3 > opStart4) return ERROR(corruption_detected);
         /* note : op4 supposed already verified within main loop */
 
         /* finish bitStreams one by one */
         HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
         HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
         HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
         HUF_decodeStreamX2(op4, &bitD4, oend,     dt, dtLog);
 
         /* check */
         endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
         if (!endSignal) return ERROR(corruption_detected);
 
         /* decoded size */
         return dstSize;
     }
 }
 
 
 static size_t HUF_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
 {
     HUF_CREATE_STATIC_DTABLEX2(DTable, HUF_MAX_TABLELOG);
     const BYTE* ip = (const BYTE*) cSrc;
     size_t errorCode;
 
     errorCode = HUF_readDTableX2 (DTable, cSrc, cSrcSize);
     if (HUF_isError(errorCode)) return errorCode;
     if (errorCode >= cSrcSize) return ERROR(srcSize_wrong);
     ip += errorCode;
     cSrcSize -= errorCode;
 
     return HUF_decompress4X2_usingDTable (dst, dstSize, ip, cSrcSize, DTable);
 }
 
 
 /***************************/
 /* double-symbols decoding */
 /***************************/
 
 static void HUF_fillDTableX4Level2(HUF_DEltX4* DTable, U32 sizeLog, const U32 consumed,
                            const U32* rankValOrigin, const int minWeight,
                            const sortedSymbol_t* sortedSymbols, const U32 sortedListSize,
                            U32 nbBitsBaseline, U16 baseSeq)
 {
     HUF_DEltX4 DElt;
     U32 rankVal[HUF_ABSOLUTEMAX_TABLELOG + 1];
     U32 s;
 
     /* get pre-calculated rankVal */
     memcpy(rankVal, rankValOrigin, sizeof(rankVal));
 
     /* fill skipped values */
     if (minWeight>1)
     {
         U32 i, skipSize = rankVal[minWeight];
         MEM_writeLE16(&(DElt.sequence), baseSeq);
         DElt.nbBits   = (BYTE)(consumed);
         DElt.length   = 1;
         for (i = 0; i < skipSize; i++)
             DTable[i] = DElt;
     }
 
     /* fill DTable */
     for (s=0; s= 1 */
 
         rankVal[weight] += length;
     }
 }
 
 typedef U32 rankVal_t[HUF_ABSOLUTEMAX_TABLELOG][HUF_ABSOLUTEMAX_TABLELOG + 1];
 
 static void HUF_fillDTableX4(HUF_DEltX4* DTable, const U32 targetLog,
                            const sortedSymbol_t* sortedList, const U32 sortedListSize,
                            const U32* rankStart, rankVal_t rankValOrigin, const U32 maxWeight,
                            const U32 nbBitsBaseline)
 {
     U32 rankVal[HUF_ABSOLUTEMAX_TABLELOG + 1];
     const int scaleLog = nbBitsBaseline - targetLog;   /* note : targetLog >= srcLog, hence scaleLog <= 1 */
     const U32 minBits  = nbBitsBaseline - maxWeight;
     U32 s;
 
     memcpy(rankVal, rankValOrigin, sizeof(rankVal));
 
     /* fill DTable */
     for (s=0; s= minBits)   /* enough room for a second symbol */
         {
             U32 sortedRank;
             int minWeight = nbBits + scaleLog;
             if (minWeight < 1) minWeight = 1;
             sortedRank = rankStart[minWeight];
             HUF_fillDTableX4Level2(DTable+start, targetLog-nbBits, nbBits,
                            rankValOrigin[nbBits], minWeight,
                            sortedList+sortedRank, sortedListSize-sortedRank,
                            nbBitsBaseline, symbol);
         }
         else
         {
             U32 i;
             const U32 end = start + length;
             HUF_DEltX4 DElt;
 
             MEM_writeLE16(&(DElt.sequence), symbol);
             DElt.nbBits   = (BYTE)(nbBits);
             DElt.length   = 1;
             for (i = start; i < end; i++)
                 DTable[i] = DElt;
         }
         rankVal[weight] += length;
     }
 }
 
 static size_t HUF_readDTableX4 (U32* DTable, const void* src, size_t srcSize)
 {
     BYTE weightList[HUF_MAX_SYMBOL_VALUE + 1];
     sortedSymbol_t sortedSymbol[HUF_MAX_SYMBOL_VALUE + 1];
     U32 rankStats[HUF_ABSOLUTEMAX_TABLELOG + 1] = { 0 };
     U32 rankStart0[HUF_ABSOLUTEMAX_TABLELOG + 2] = { 0 };
     U32* const rankStart = rankStart0+1;
     rankVal_t rankVal;
     U32 tableLog, maxW, sizeOfSort, nbSymbols;
     const U32 memLog = DTable[0];
     const BYTE* ip = (const BYTE*) src;
     size_t iSize = ip[0];
     void* ptr = DTable;
     HUF_DEltX4* const dt = ((HUF_DEltX4*)ptr) + 1;
 
     HUF_STATIC_ASSERT(sizeof(HUF_DEltX4) == sizeof(U32));   /* if compilation fails here, assertion is false */
     if (memLog > HUF_ABSOLUTEMAX_TABLELOG) return ERROR(tableLog_tooLarge);
     //memset(weightList, 0, sizeof(weightList));   /* is not necessary, even though some analyzer complain ... */
 
     iSize = HUF_readStats(weightList, HUF_MAX_SYMBOL_VALUE + 1, rankStats, &nbSymbols, &tableLog, src, srcSize);
     if (HUF_isError(iSize)) return iSize;
 
     /* check result */
     if (tableLog > memLog) return ERROR(tableLog_tooLarge);   /* DTable can't fit code depth */
 
     /* find maxWeight */
     for (maxW = tableLog; rankStats[maxW]==0; maxW--)
         {if (!maxW) return ERROR(GENERIC); }  /* necessarily finds a solution before maxW==0 */
 
     /* Get start index of each weight */
     {
         U32 w, nextRankStart = 0;
         for (w=1; w<=maxW; w++)
         {
             U32 current = nextRankStart;
             nextRankStart += rankStats[w];
             rankStart[w] = current;
         }
         rankStart[0] = nextRankStart;   /* put all 0w symbols at the end of sorted list*/
         sizeOfSort = nextRankStart;
     }
 
     /* sort symbols by weight */
     {
         U32 s;
         for (s=0; s> consumed;
             }
         }
     }
 
     HUF_fillDTableX4(dt, memLog,
                    sortedSymbol, sizeOfSort,
                    rankStart0, rankVal, maxW,
                    tableLog+1);
 
     return iSize;
 }
 
 
 static U32 HUF_decodeSymbolX4(void* op, BIT_DStream_t* DStream, const HUF_DEltX4* dt, const U32 dtLog)
 {
     const size_t val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
     memcpy(op, dt+val, 2);
     BIT_skipBits(DStream, dt[val].nbBits);
     return dt[val].length;
 }
 
 static U32 HUF_decodeLastSymbolX4(void* op, BIT_DStream_t* DStream, const HUF_DEltX4* dt, const U32 dtLog)
 {
     const size_t val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
     memcpy(op, dt+val, 1);
     if (dt[val].length==1) BIT_skipBits(DStream, dt[val].nbBits);
     else
     {
         if (DStream->bitsConsumed < (sizeof(DStream->bitContainer)*8))
         {
             BIT_skipBits(DStream, dt[val].nbBits);
             if (DStream->bitsConsumed > (sizeof(DStream->bitContainer)*8))
                 DStream->bitsConsumed = (sizeof(DStream->bitContainer)*8);   /* ugly hack; works only because it's the last symbol. Note : can't easily extract nbBits from just this symbol */
         }
     }
     return 1;
 }
 
 
 #define HUF_DECODE_SYMBOLX4_0(ptr, DStreamPtr) \
     ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
 
 #define HUF_DECODE_SYMBOLX4_1(ptr, DStreamPtr) \
     if (MEM_64bits() || (HUF_MAX_TABLELOG<=12)) \
         ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
 
 #define HUF_DECODE_SYMBOLX4_2(ptr, DStreamPtr) \
     if (MEM_64bits()) \
         ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
 
 static inline size_t HUF_decodeStreamX4(BYTE* p, BIT_DStream_t* bitDPtr, BYTE* const pEnd, const HUF_DEltX4* const dt, const U32 dtLog)
 {
     BYTE* const pStart = p;
 
     /* up to 8 symbols at a time */
     while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p < pEnd-7))
     {
         HUF_DECODE_SYMBOLX4_2(p, bitDPtr);
         HUF_DECODE_SYMBOLX4_1(p, bitDPtr);
         HUF_DECODE_SYMBOLX4_2(p, bitDPtr);
         HUF_DECODE_SYMBOLX4_0(p, bitDPtr);
     }
 
     /* closer to the end */
     while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p <= pEnd-2))
         HUF_DECODE_SYMBOLX4_0(p, bitDPtr);
 
     while (p <= pEnd-2)
         HUF_DECODE_SYMBOLX4_0(p, bitDPtr);   /* no need to reload : reached the end of DStream */
 
     if (p < pEnd)
         p += HUF_decodeLastSymbolX4(p, bitDPtr, dt, dtLog);
 
     return p-pStart;
 }
 
 
 
 static size_t HUF_decompress4X4_usingDTable(
           void* dst,  size_t dstSize,
     const void* cSrc, size_t cSrcSize,
     const U32* DTable)
 {
     if (cSrcSize < 10) return ERROR(corruption_detected);   /* strict minimum : jump table + 1 byte per stream */
 
     {
         const BYTE* const istart = (const BYTE*) cSrc;
         BYTE* const ostart = (BYTE*) dst;
         BYTE* const oend = ostart + dstSize;
 
         const void* ptr = DTable;
         const HUF_DEltX4* const dt = ((const HUF_DEltX4*)ptr) +1;
         const U32 dtLog = DTable[0];
         size_t errorCode;
 
         /* Init */
         BIT_DStream_t bitD1;
         BIT_DStream_t bitD2;
         BIT_DStream_t bitD3;
         BIT_DStream_t bitD4;
         const size_t length1 = MEM_readLE16(istart);
         const size_t length2 = MEM_readLE16(istart+2);
         const size_t length3 = MEM_readLE16(istart+4);
         size_t length4;
         const BYTE* const istart1 = istart + 6;  /* jumpTable */
         const BYTE* const istart2 = istart1 + length1;
         const BYTE* const istart3 = istart2 + length2;
         const BYTE* const istart4 = istart3 + length3;
         const size_t segmentSize = (dstSize+3) / 4;
         BYTE* const opStart2 = ostart + segmentSize;
         BYTE* const opStart3 = opStart2 + segmentSize;
         BYTE* const opStart4 = opStart3 + segmentSize;
         BYTE* op1 = ostart;
         BYTE* op2 = opStart2;
         BYTE* op3 = opStart3;
         BYTE* op4 = opStart4;
         U32 endSignal;
 
         length4 = cSrcSize - (length1 + length2 + length3 + 6);
         if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
         errorCode = BIT_initDStream(&bitD1, istart1, length1);
         if (HUF_isError(errorCode)) return errorCode;
         errorCode = BIT_initDStream(&bitD2, istart2, length2);
         if (HUF_isError(errorCode)) return errorCode;
         errorCode = BIT_initDStream(&bitD3, istart3, length3);
         if (HUF_isError(errorCode)) return errorCode;
         errorCode = BIT_initDStream(&bitD4, istart4, length4);
         if (HUF_isError(errorCode)) return errorCode;
 
         /* 16-32 symbols per loop (4-8 symbols per stream) */
         endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
         for ( ; (endSignal==BIT_DStream_unfinished) && (op4<(oend-7)) ; )
         {
             HUF_DECODE_SYMBOLX4_2(op1, &bitD1);
             HUF_DECODE_SYMBOLX4_2(op2, &bitD2);
             HUF_DECODE_SYMBOLX4_2(op3, &bitD3);
             HUF_DECODE_SYMBOLX4_2(op4, &bitD4);
             HUF_DECODE_SYMBOLX4_1(op1, &bitD1);
             HUF_DECODE_SYMBOLX4_1(op2, &bitD2);
             HUF_DECODE_SYMBOLX4_1(op3, &bitD3);
             HUF_DECODE_SYMBOLX4_1(op4, &bitD4);
             HUF_DECODE_SYMBOLX4_2(op1, &bitD1);
             HUF_DECODE_SYMBOLX4_2(op2, &bitD2);
             HUF_DECODE_SYMBOLX4_2(op3, &bitD3);
             HUF_DECODE_SYMBOLX4_2(op4, &bitD4);
             HUF_DECODE_SYMBOLX4_0(op1, &bitD1);
             HUF_DECODE_SYMBOLX4_0(op2, &bitD2);
             HUF_DECODE_SYMBOLX4_0(op3, &bitD3);
             HUF_DECODE_SYMBOLX4_0(op4, &bitD4);
 
             endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
         }
 
         /* check corruption */
         if (op1 > opStart2) return ERROR(corruption_detected);
         if (op2 > opStart3) return ERROR(corruption_detected);
         if (op3 > opStart4) return ERROR(corruption_detected);
         /* note : op4 supposed already verified within main loop */
 
         /* finish bitStreams one by one */
         HUF_decodeStreamX4(op1, &bitD1, opStart2, dt, dtLog);
         HUF_decodeStreamX4(op2, &bitD2, opStart3, dt, dtLog);
         HUF_decodeStreamX4(op3, &bitD3, opStart4, dt, dtLog);
         HUF_decodeStreamX4(op4, &bitD4, oend,     dt, dtLog);
 
         /* check */
         endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
         if (!endSignal) return ERROR(corruption_detected);
 
         /* decoded size */
         return dstSize;
     }
 }
 
 
 static size_t HUF_decompress4X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
 {
     HUF_CREATE_STATIC_DTABLEX4(DTable, HUF_MAX_TABLELOG);
     const BYTE* ip = (const BYTE*) cSrc;
 
     size_t hSize = HUF_readDTableX4 (DTable, cSrc, cSrcSize);
     if (HUF_isError(hSize)) return hSize;
     if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
     ip += hSize;
     cSrcSize -= hSize;
 
     return HUF_decompress4X4_usingDTable (dst, dstSize, ip, cSrcSize, DTable);
 }
 
 
 /**********************************/
 /* quad-symbol decoding           */
 /**********************************/
 typedef struct { BYTE nbBits; BYTE nbBytes; } HUF_DDescX6;
 typedef union { BYTE byte[4]; U32 sequence; } HUF_DSeqX6;
 
 /* recursive, up to level 3; may benefit from