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| Source at commit 1406 created 12 years 10 months ago. By meklort, Revert drivers.c so that kexts are only loaded when OSBundleRequired is set and that value is not safe mode. Added some comments about it too. | |
|---|---|
| 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 | |
