From 824f782c3f8f2db8e884b0c555d21ed4cfd6fff2 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Tue, 20 Mar 2007 04:05:10 +0100 Subject: [PATCH] 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 Signed-off-by: Junio C Hamano --- xdiff/xutils.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/xdiff/xutils.c b/xdiff/xutils.c index 3653864e4..bf91c0f73 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; -- 2.30.2