reenable word-at-at-time copying in memmove

[musl] / src / string / memmove.c

diff --git a/src/string/memmove.c b/src/string/memmove.c
index 9153a64..27f670e 100644 (file)
--- 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;
 }