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contrib/zlib/inflate.h
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svn:keywords | FreeBSD=%H \ No newline at end of property | null |
/* inflate.h -- internal inflate state definition | |||||
* Copyright (C) 1995-2016 Mark Adler | |||||
* For conditions of distribution and use, see copyright notice in zlib.h | |||||
*/ | |||||
/* WARNING: this file should *not* be used by applications. It is | |||||
part of the implementation of the compression library and is | |||||
subject to change. Applications should only use zlib.h. | |||||
*/ | |||||
/* define NO_GZIP when compiling if you want to disable gzip header and | |||||
trailer decoding by inflate(). NO_GZIP would be used to avoid linking in | |||||
the crc code when it is not needed. For shared libraries, gzip decoding | |||||
should be left enabled. */ | |||||
#ifndef NO_GZIP | |||||
# define GUNZIP | |||||
#endif | |||||
/* Possible inflate modes between inflate() calls */ | |||||
typedef enum { | |||||
HEAD = 16180, /* i: waiting for magic header */ | |||||
FLAGS, /* i: waiting for method and flags (gzip) */ | |||||
TIME, /* i: waiting for modification time (gzip) */ | |||||
OS, /* i: waiting for extra flags and operating system (gzip) */ | |||||
EXLEN, /* i: waiting for extra length (gzip) */ | |||||
EXTRA, /* i: waiting for extra bytes (gzip) */ | |||||
NAME, /* i: waiting for end of file name (gzip) */ | |||||
COMMENT, /* i: waiting for end of comment (gzip) */ | |||||
HCRC, /* i: waiting for header crc (gzip) */ | |||||
DICTID, /* i: waiting for dictionary check value */ | |||||
DICT, /* waiting for inflateSetDictionary() call */ | |||||
TYPE, /* i: waiting for type bits, including last-flag bit */ | |||||
TYPEDO, /* i: same, but skip check to exit inflate on new block */ | |||||
STORED, /* i: waiting for stored size (length and complement) */ | |||||
COPY_, /* i/o: same as COPY below, but only first time in */ | |||||
COPY, /* i/o: waiting for input or output to copy stored block */ | |||||
TABLE, /* i: waiting for dynamic block table lengths */ | |||||
LENLENS, /* i: waiting for code length code lengths */ | |||||
CODELENS, /* i: waiting for length/lit and distance code lengths */ | |||||
LEN_, /* i: same as LEN below, but only first time in */ | |||||
LEN, /* i: waiting for length/lit/eob code */ | |||||
LENEXT, /* i: waiting for length extra bits */ | |||||
DIST, /* i: waiting for distance code */ | |||||
DISTEXT, /* i: waiting for distance extra bits */ | |||||
MATCH, /* o: waiting for output space to copy string */ | |||||
LIT, /* o: waiting for output space to write literal */ | |||||
CHECK, /* i: waiting for 32-bit check value */ | |||||
LENGTH, /* i: waiting for 32-bit length (gzip) */ | |||||
DONE, /* finished check, done -- remain here until reset */ | |||||
BAD, /* got a data error -- remain here until reset */ | |||||
MEM, /* got an inflate() memory error -- remain here until reset */ | |||||
SYNC /* looking for synchronization bytes to restart inflate() */ | |||||
} inflate_mode; | |||||
/* | |||||
State transitions between above modes - | |||||
(most modes can go to BAD or MEM on error -- not shown for clarity) | |||||
Process header: | |||||
HEAD -> (gzip) or (zlib) or (raw) | |||||
(gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT -> | |||||
HCRC -> TYPE | |||||
(zlib) -> DICTID or TYPE | |||||
DICTID -> DICT -> TYPE | |||||
(raw) -> TYPEDO | |||||
Read deflate blocks: | |||||
TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK | |||||
STORED -> COPY_ -> COPY -> TYPE | |||||
TABLE -> LENLENS -> CODELENS -> LEN_ | |||||
LEN_ -> LEN | |||||
Read deflate codes in fixed or dynamic block: | |||||
LEN -> LENEXT or LIT or TYPE | |||||
LENEXT -> DIST -> DISTEXT -> MATCH -> LEN | |||||
LIT -> LEN | |||||
Process trailer: | |||||
CHECK -> LENGTH -> DONE | |||||
*/ | |||||
/* State maintained between inflate() calls -- approximately 7K bytes, not | |||||
including the allocated sliding window, which is up to 32K bytes. */ | |||||
struct inflate_state { | |||||
z_streamp strm; /* pointer back to this zlib stream */ | |||||
inflate_mode mode; /* current inflate mode */ | |||||
int last; /* true if processing last block */ | |||||
int wrap; /* bit 0 true for zlib, bit 1 true for gzip, | |||||
bit 2 true to validate check value */ | |||||
int havedict; /* true if dictionary provided */ | |||||
int flags; /* gzip header method and flags (0 if zlib) */ | |||||
unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ | |||||
unsigned long check; /* protected copy of check value */ | |||||
unsigned long total; /* protected copy of output count */ | |||||
gz_headerp head; /* where to save gzip header information */ | |||||
/* sliding window */ | |||||
unsigned wbits; /* log base 2 of requested window size */ | |||||
unsigned wsize; /* window size or zero if not using window */ | |||||
unsigned whave; /* valid bytes in the window */ | |||||
unsigned wnext; /* window write index */ | |||||
unsigned char FAR *window; /* allocated sliding window, if needed */ | |||||
/* bit accumulator */ | |||||
unsigned long hold; /* input bit accumulator */ | |||||
unsigned bits; /* number of bits in "in" */ | |||||
/* for string and stored block copying */ | |||||
unsigned length; /* literal or length of data to copy */ | |||||
unsigned offset; /* distance back to copy string from */ | |||||
/* for table and code decoding */ | |||||
unsigned extra; /* extra bits needed */ | |||||
/* fixed and dynamic code tables */ | |||||
code const FAR *lencode; /* starting table for length/literal codes */ | |||||
code const FAR *distcode; /* starting table for distance codes */ | |||||
unsigned lenbits; /* index bits for lencode */ | |||||
unsigned distbits; /* index bits for distcode */ | |||||
/* dynamic table building */ | |||||
unsigned ncode; /* number of code length code lengths */ | |||||
unsigned nlen; /* number of length code lengths */ | |||||
unsigned ndist; /* number of distance code lengths */ | |||||
unsigned have; /* number of code lengths in lens[] */ | |||||
code FAR *next; /* next available space in codes[] */ | |||||
unsigned short lens[320]; /* temporary storage for code lengths */ | |||||
unsigned short work[288]; /* work area for code table building */ | |||||
code codes[ENOUGH]; /* space for code tables */ | |||||
int sane; /* if false, allow invalid distance too far */ | |||||
int back; /* bits back of last unprocessed length/lit */ | |||||
unsigned was; /* initial length of match */ | |||||
}; |