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| Source at commit 1808 created 12 years 4 months ago. By blackosx, Revise layout of package installer 'Welcome' file so it looks cleaner. Change the copyright notice to begin from 2009 as seen in the Chameleon 2.0 r431 installer. Should this date be set earlier? | |
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| 1 | /*␊ |
| 2 | * memmem.c␊ |
| 3 | *␊ |
| 4 | * Find a byte string inside a longer byte string␊ |
| 5 | *␊ |
| 6 | * This uses the "Not So Naive" algorithm, a very simple but␊ |
| 7 | * usually effective algorithm, see:␊ |
| 8 | *␊ |
| 9 | * http://www-igm.univ-mlv.fr/~lecroq/string/␊ |
| 10 | */␊ |
| 11 | ␊ |
| 12 | #include <string.h>␊ |
| 13 | ␊ |
| 14 | void *memmem(const void *haystack, size_t n, const void *needle, size_t m)␊ |
| 15 | {␊ |
| 16 | ␉const unsigned char *y = (const unsigned char *)haystack;␊ |
| 17 | ␉const unsigned char *x = (const unsigned char *)needle;␊ |
| 18 | ␊ |
| 19 | ␉size_t j, k, l;␊ |
| 20 | ␊ |
| 21 | ␉if (m > n || !m || !n)␊ |
| 22 | ␉␉return NULL;␊ |
| 23 | ␊ |
| 24 | ␉if (1 != m) {␊ |
| 25 | ␉␉if (x[0] == x[1]) {␊ |
| 26 | ␉␉␉k = 2;␊ |
| 27 | ␉␉␉l = 1;␊ |
| 28 | ␉␉} else {␊ |
| 29 | ␉␉␉k = 1;␊ |
| 30 | ␉␉␉l = 2;␊ |
| 31 | ␉␉}␊ |
| 32 | ␊ |
| 33 | ␉␉j = 0;␊ |
| 34 | ␉␉while (j <= n - m) {␊ |
| 35 | ␉␉␉if (x[1] != y[j + 1]) {␊ |
| 36 | ␉␉␉␉j += k;␊ |
| 37 | ␉␉␉} else {␊ |
| 38 | ␉␉␉␉if (!memcmp(x + 2, y + j + 2, m - 2)␊ |
| 39 | ␉␉␉␉ && x[0] == y[j])␊ |
| 40 | ␉␉␉␉␉return (void *)&y[j];␊ |
| 41 | ␉␉␉␉j += l;␊ |
| 42 | ␉␉␉}␊ |
| 43 | ␉␉}␊ |
| 44 | ␉} else␊ |
| 45 | ␉␉do {␊ |
| 46 | ␉␉␉if (*y == *x)␊ |
| 47 | ␉␉␉␉return (void *)y;␊ |
| 48 | ␉␉␉y++;␊ |
| 49 | ␉␉} while (--n);␊ |
| 50 | ␊ |
| 51 | ␉return NULL;␊ |
| 52 | }␊ |
| 53 | |
