diff options
| -rw-r--r-- | src/string/memmove.c | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/src/string/memmove.c b/src/string/memmove.c index 9153a644..27f670e1 100644 --- a/src/string/memmove.c +++ b/src/string/memmove.c @@ -1,13 +1,36 @@ #include <string.h> +#include <stdint.h> + +#define WT size_t +#define WS (sizeof(WT)) void *memmove(void *dest, const void *src, size_t n) { char *d = dest; const char *s = src; + if (d==s) return d; - if ((size_t)(d-s) < n) - while (n--) d[n] = s[n]; - else - while (n--) *d++ = *s++; + if (s+n <= d || d+n <= s) return memcpy(d, s, n); + + if (d<s) { + 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; + } + for (; n; n--) *d++ = *s++; + } else { + 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); + } + while (n) n--, d[n] = s[n]; + } + return dest; } |