Merge branch 'ds/midx-expire-repack'
[git/git.git] / compat / memmem.c
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1#include "../git-compat-util.h"
2
3void *gitmemmem(const void *haystack, size_t haystack_len,
4 const void *needle, size_t needle_len)
5{
6 const char *begin = haystack;
7 const char *last_possible = begin + haystack_len - needle_len;
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8 const char *tail = needle;
9 char point;
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10
11 /*
12 * The first occurrence of the empty string is deemed to occur at
13 * the beginning of the string.
14 */
15 if (needle_len == 0)
16 return (void *)begin;
17
18 /*
19 * Sanity check, otherwise the loop might search through the whole
20 * memory.
21 */
22 if (haystack_len < needle_len)
23 return NULL;
24
56384e61 25 point = *tail++;
b21b9f1d 26 for (; begin <= last_possible; begin++) {
56384e61 27 if (*begin == point && !memcmp(begin + 1, tail, needle_len - 1))
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28 return (void *)begin;
29 }
30
31 return NULL;
32}