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Merge "memmove: Don't call memcpy if regions overlap"

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This commit is contained in:
Nick Kralevich 2012-07-12 10:06:27 -07:00 committed by android code review
commit 86a4fca0b4
1 changed files with 4 additions and 3 deletions
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7
libc/string/memmove.c
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@ -32,10 +32,11 @@ void *memmove(void *dst, const void *src, size_t n)
{ {
const char *p = src; const char *p = src;
char *q = dst; char *q = dst;
/* We can use the optimized memcpy if the destination is below the /* We can use the optimized memcpy if the source and destination
* source (i.e. q < p), or if it is completely over it (i.e. q >= p+n). * don't overlap.
*/ */
if (__builtin_expect((q < p) || ((size_t)(q - p) >= n), 1)) { if (__builtin_expect(((q < p) && ((size_t)(p - q) >= n))
|| ((p < q) && ((size_t)(q - p) >= n)), 1)) {
return memcpy(dst, src, n); return memcpy(dst, src, n);
} else { } else {
bcopy(src, dst, n); bcopy(src, dst, n);