git/compat/memmem.c
René Scharfe b21b9f1de3 add memmem()
memmem() is a nice GNU extension for searching a length limited string
in another one.

This compat version is based on the version found in glibc 2.2 (GPL 2);
I only removed the optimization of checking the first char by hand, and
generally tried to keep the code simple.  We can add it back if memcmp
shows up high in a profile, but for now I prefer to keep it (almost
trivially) simple.

Since I don't really know which platforms beside those with a glibc
have their own memmem(), I used a heuristic: if NO_STRCASESTR is set,
then NO_MEMMEM is set, too.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-09-06 22:46:00 -07:00

30 lines
668 B
C

#include "../git-compat-util.h"
void *gitmemmem(const void *haystack, size_t haystack_len,
const void *needle, size_t needle_len)
{
const char *begin = haystack;
const char *last_possible = begin + haystack_len - needle_len;
/*
* The first occurrence of the empty string is deemed to occur at
* the beginning of the string.
*/
if (needle_len == 0)
return (void *)begin;
/*
* Sanity check, otherwise the loop might search through the whole
* memory.
*/
if (haystack_len < needle_len)
return NULL;
for (; begin <= last_possible; begin++) {
if (!memcmp(begin, needle, needle_len))
return (void *)begin;
}
return NULL;
}