1#include <string.h> 2#include <stdint.h> 3 4#define WT size_t 5#define WS (sizeof(WT)) 6 7void *memmove(void *dest, const void *src, size_t n) 8{ 9 char *d = dest; 10 const char *s = src; 11 12 if (d==s) return d; 13 if (s+n <= d || d+n <= s) return memcpy(d, s, n); 14 15 if (d<s) { 16 if ((uintptr_t)s % WS == (uintptr_t)d % WS) { 17 while ((uintptr_t)d % WS) { 18 if (!n--) return dest; 19 *d++ = *s++; 20 } 21 for (; n>=WS; n-=WS, d+=WS, s+=WS) *(WT *)d = *(WT *)s; 22 } 23 for (; n; n--) *d++ = *s++; 24 } else { 25 if ((uintptr_t)s % WS == (uintptr_t)d % WS) { 26 while ((uintptr_t)(d+n) % WS) { 27 if (!n--) return dest; 28 d[n] = s[n]; 29 } 30 while (n>=WS) n-=WS, *(WT *)(d+n) = *(WT *)(s+n); 31 } 32 while (n) n--, d[n] = s[n]; 33 } 34 35 return dest; 36} 37