arm-trusted-firmware/lib/libc/memmove.c
Antonio Nino Diaz 4661abc7c4 libc: Cleanup remaining files
The existing files had some style problems that this patch fixes.

Change-Id: I794e0d96e52f8da0ffa0d70a41f36c4432b4e563
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
2018-08-22 10:26:04 +01:00

31 lines
927 B
C

/*
* Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <string.h>
void *memmove(void *dst, const void *src, size_t len)
{
/*
* The following test makes use of unsigned arithmetic overflow to
* more efficiently test the condition !(src <= dst && dst < str+len).
* It also avoids the situation where the more explicit test would give
* incorrect results were the calculation str+len to overflow (though
* that issue is probably moot as such usage is probably undefined
* behaviour and a bug anyway.
*/
if ((size_t)dst - (size_t)src >= len) {
/* destination not in source data, so can safely use memcpy */
return memcpy(dst, src, len);
} else {
/* copy backwards... */
const char *end = dst;
const char *s = (const char *)src + len;
char *d = (char *)dst + len;
while (d != end)
*--d = *--s;
}
return dst;
}