Page MenuHomeFreeBSD
Files F151392479

D26128.id76039.diff
No OneTemporary
Actions

D26128.id76039.diff
View Options

Index: share/man/man9/bitset.9
===================================================================
--- share/man/man9/bitset.9
+++ share/man/man9/bitset.9
@@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd December 12, 2019
+.Dd August 20, 2020
.Dt BITSET 9
.Os
.Sh NAME
@@ -43,6 +43,7 @@
.Nm BIT_EMPTY ,
.Nm BIT_ISFULLSET ,
.Nm BIT_FFS ,
+.Nm BIT_FFS_AT ,
.Nm BIT_FLS ,
.Nm BIT_COUNT ,
.Nm BIT_SUBSET ,
@@ -86,6 +87,8 @@
.Ft int
.Fn BIT_FFS "const SETSIZE" "struct STRUCTNAME *bitset"
.Ft int
+.Fn BIT_FFS_AT "const SETSIZE" "struct STRUCTNAME *bitset" "int start"
+.Ft int
.Fn BIT_FLS "const SETSIZE" "struct STRUCTNAME *bitset"
.Ft int
.Fn BIT_COUNT "const SETSIZE" "struct STRUCTNAME *bitset"
@@ -285,6 +288,18 @@
macro, you must subtract one from the result.
.Pp
The
+.Fn BIT_FFS_AT
+macro returns the 1-index of the first (lowest) set bit in
+.Fa bitset ,
+which is greater than the given 1-indexed
+.Fa start ,
+or zero if no bits in
+.Fa bitset
+greater than
+.Fa start
+are set.
+.Pp
+The
.Fn BIT_FLS
macro returns the 1-index of the last (highest) set bit in
.Fa bitset ,
@@ -518,7 +533,8 @@
.Fn BITSET_DEFINE .
.Pp
Unlike every other reference to individual set members, which are zero-indexed,
-.Fn BIT_FFS
+.Fn BIT_FFS ,
+.Fn BIT_FFS_AT
and
.Fn BIT_FLS
return a one-indexed result (or zero if the set is empty).
Index: sys/sys/bitset.h
===================================================================
--- sys/sys/bitset.h
+++ sys/sys/bitset.h
@@ -207,21 +207,32 @@
(f)->__bits[__i]); \
} while (0)
-#define BIT_FFS(_s, p) __extension__ ({ \
+/*
+ * Note that `start` and the returned value from BIT_FFS_AT are
+ * 1-based bit indices.
+ */
+#define BIT_FFS_AT(_s, p, start) __extension__ ({ \
__size_t __i; \
+ long __mask; \
int __bit; \
\
+ __mask = ~0UL << ((start) % _BITSET_BITS); \
__bit = 0; \
- for (__i = 0; __i < __bitset_words((_s)); __i++) { \
- if ((p)->__bits[__i] != 0) { \
- __bit = ffsl((p)->__bits[__i]); \
+ for (__i = __bitset_word(_s, start); \
+ __i < __bitset_words((_s)); \
+ __i++) { \
+ if (((p)->__bits[__i] & __mask) != 0) { \
+ __bit = ffsl((p)->__bits[__i] & __mask); \
__bit += __i * _BITSET_BITS; \
break; \
} \
+ __mask = ~0UL; \
} \
__bit; \
})
+#define BIT_FFS(_s, p) BIT_FFS_AT(_s, p, 0)
+
#define BIT_FLS(_s, p) __extension__ ({ \
__size_t __i; \
int __bit; \

File Metadata

Mime Type
text/plain
Expires
Thu, Apr 9, 2:58 AM (9 h, 20 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
31130313
Default Alt Text
D26128.id76039.diff (2 KB)

Event Timeline