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#include <string.h> #include <stdint.h> #ifdef __GNUC__ typedef __attribute__((__may_alias__)) size_t WT; #define WS (sizeof(WT)) #endif void *memmove(void *dest, const void *src, size_t n) { char *d = dest; const char *s = src; if (d==s) return d; if ((uintptr_t)s-(uintptr_t)d-n <= -2*n) return memcpy(d, s, n); if (d<s) { #ifdef __GNUC__ if ((uintptr_t)s % WS == (uintptr_t)d % WS) { while ((uintptr_t)d % WS) { if (!n--) return dest; *d++ = *s++; } for (; n>=WS; n-=WS, d+=WS, s+=WS) *(WT *)d = *(WT *)s; } #endif for (; n; n--) *d++ = *s++; } else { #ifdef __GNUC__ if ((uintptr_t)s % WS == (uintptr_t)d % WS) { while ((uintptr_t)(d+n) % WS) { if (!n--) return dest; d[n] = s[n]; } while (n>=WS) n-=WS, *(WT *)(d+n) = *(WT *)(s+n); } #endif while (n) n--, d[n] = s[n]; } return dest; } |