diff options
| author |  Johannes Schindelin <Johannes.Schindelin@gmx.de> | 2007-03-20 04:05:10 +0100 |
|---|---|---|
| committer |  Junio C Hamano <junkio@cox.net> | 2007-03-19 22:17:25 -0700 |
| commit | 824f782c3f8f2db8e884b0c555d21ed4cfd6fff2 (patch) | |
| tree | ae980f46cbbc5607496d1fe8897b0f87e3d947f9 | |
| parent | blame: micro-optimize cmp_suspect() (diff) | |
| download | tgif-824f782c3f8f2db8e884b0c555d21ed4cfd6fff2.tar.xz | |
xdiff/xutils.c(xdl_hash_record): factor out whitespace handling
Since in at least one use case, xdl_hash_record() takes over 15% of the
CPU time, it makes sense to even micro-optimize it. For many cases, no
whitespace special handling is needed, and in these cases we should not
even bother to check for whitespace in _every_ iteration of the loop.
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
| -rw-r--r-- | xdiff/xutils.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/xdiff/xutils.c b/xdiff/xutils.c index 3653864e4b..bf91c0f73c 100644 --- a/xdiff/xutils.c +++ b/xdiff/xutils.c @@ -236,12 +236,13 @@ int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags) return 0; } -unsigned long xdl_hash_record(char const **data, char const *top, long flags) { +static unsigned long xdl_hash_record_with_whitespace(char const **data, + char const *top, long flags) { unsigned long ha = 5381; char const *ptr = *data; for (; ptr < top && *ptr != '\n'; ptr++) { - if (isspace(*ptr) && (flags & XDF_WHITESPACE_FLAGS)) { + if (isspace(*ptr)) { const char *ptr2 = ptr; while (ptr + 1 < top && isspace(ptr[1]) && ptr[1] != '\n') @@ -270,6 +271,23 @@ unsigned long xdl_hash_record(char const **data, char const *top, long flags) { } +unsigned long xdl_hash_record(char const **data, char const *top, long flags) { + unsigned long ha = 5381; + char const *ptr = *data; + + if (flags & XDF_WHITESPACE_FLAGS) + return xdl_hash_record_with_whitespace(data, top, flags); + + for (; ptr < top && *ptr != '\n'; ptr++) { + ha += (ha << 5); + ha ^= (unsigned long) *ptr; + } + *data = ptr < top ? ptr + 1: ptr; + + return ha; +} + + unsigned int xdl_hashbits(unsigned int size) { unsigned int val = 1, bits = 0; |