freebsd-skq/contrib/ldns/compat/memmove.c
2013-02-15 13:44:18 +00:00

44 lines
953 B
C

/*
* memmove.c: memmove compat implementation.
*
* Copyright (c) 2001-2008, NLnet Labs. All rights reserved.
*
* See LICENSE for the license.
*/
#include <ldns/config.h>
#include <stdlib.h>
void *memmove(void *dest, const void *src, size_t n);
void *memmove(void *dest, const void *src, size_t n)
{
uint8_t* from = (uint8_t*) src;
uint8_t* to = (uint8_t*) dest;
if (from == to || n == 0)
return dest;
if (to > from && to-from < (int)n) {
/* to overlaps with from */
/* <from......> */
/* <to........> */
/* copy in reverse, to avoid overwriting from */
int i;
for(i=n-1; i>=0; i--)
to[i] = from[i];
return dest;
}
if (from > to && from-to < (int)n) {
/* to overlaps with from */
/* <from......> */
/* <to........> */
/* copy forwards, to avoid overwriting from */
size_t i;
for(i=0; i<n; i++)
to[i] = from[i];
return dest;
}
memcpy(dest, src, n);
return dest;
}