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b21b9f1de3
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>
29 lines
668 B
C
29 lines
668 B
C
#include "../git-compat-util.h"
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void *gitmemmem(const void *haystack, size_t haystack_len,
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const void *needle, size_t needle_len)
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{
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const char *begin = haystack;
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const char *last_possible = begin + haystack_len - needle_len;
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/*
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* The first occurrence of the empty string is deemed to occur at
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* the beginning of the string.
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*/
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if (needle_len == 0)
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return (void *)begin;
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/*
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* Sanity check, otherwise the loop might search through the whole
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* memory.
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*/
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if (haystack_len < needle_len)
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return NULL;
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for (; begin <= last_possible; begin++) {
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if (!memcmp(begin, needle, needle_len))
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return (void *)begin;
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}
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return NULL;
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}
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