| 1 | #include <stddef.h> |
| 2 | #include <stdint.h> |
| 3 | |
| 4 | void *memcpy(void *dest, const void *src, size_t n) { |
| 5 | uint8_t *pdest = dest; |
| 6 | const uint8_t *psrc = src; |
| 7 | |
| 8 | for (size_t i = 0; i < n; i++) { |
| 9 | pdest[i] = psrc[i]; |
| 10 | } |
| 11 | |
| 12 | return dest; |
| 13 | } |
| 14 | |
| 15 | void *memset(void *s, int c, size_t n) { |
| 16 | uint8_t *p = s; |
| 17 | |
| 18 | for (size_t i = 0; i < n; i++) { |
| 19 | p[i] = (uint8_t)c; |
| 20 | } |
| 21 | |
| 22 | return s; |
| 23 | } |
| 24 | |
| 25 | void *memmove(void *dest, const void *src, size_t n) { |
| 26 | uint8_t *pdest = dest; |
| 27 | const uint8_t *psrc = src; |
| 28 | |
| 29 | if ((uintptr_t)src > (uintptr_t)dest) { |
| 30 | for (size_t i = 0; i < n; i++) { |
| 31 | pdest[i] = psrc[i]; |
| 32 | } |
| 33 | } else if ((uintptr_t)src < (uintptr_t)dest) { |
| 34 | for (size_t i = n; i > 0; i--) { |
| 35 | pdest[i-1] = psrc[i-1]; |
| 36 | } |
| 37 | } |
| 38 | |
| 39 | return dest; |
| 40 | } |
| 41 | |
| 42 | int memcmp(const void *s1, const void *s2, size_t n) { |
| 43 | const uint8_t *p1 = s1; |
| 44 | const uint8_t *p2 = s2; |
| 45 | |
| 46 | for (size_t i = 0; i < n; i++) { |
| 47 | if (p1[i] != p2[i]) |
| 48 | return p1[i] < p2[i] ? -1 : 1; |
| 49 | } |
| 50 | |
| 51 | return 0; |
| 52 | } |
