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