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/*
Copyright (c) 2002 Jeff Johnston <jjohnstn@redhat.com>
*/
/*
FUNCTION
<<mempcpy>>---copy memory regions and return end pointer
SYNOPSIS
#include <string.h>
void* mempcpy(void *<[out]>, const void *<[in]>, size_t <[n]>);
DESCRIPTION
This function copies <[n]> bytes from the memory region
pointed to by <[in]> to the memory region pointed to by
<[out]>.
If the regions overlap, the behavior is undefined.
RETURNS
<<mempcpy>> returns a pointer to the byte following the
last byte copied to the <[out]> region.
PORTABILITY
<<mempcpy>> is a GNU extension.
<<mempcpy>> requires no supporting OS subroutines.
*/
#define _GNU_SOURCE
#include <stddef.h>
#include <limits.h>
#include <string.h>
#include "local.h"
void *
mempcpy(void *dst0, const void *src0, size_t len0)
{
#if defined(__PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
char *dst = (char *)dst0;
char *src = (char *)src0;
while (len0--) {
*dst++ = *src++;
}
return dst;
#else
char *dst = dst0;
const char *src = src0;
long *aligned_dst;
const long *aligned_src;
/* If the size is small, or either SRC or DST is unaligned,
then punt into the byte copy loop. This should be rare. */
if (!TOO_SMALL_LITTLE_BLOCK(len0) && !UNALIGNED_X_Y(src, dst)) {
aligned_dst = (long *)dst;
aligned_src = (long *)src;
/* Copy 4X long words at a time if possible. */
while (!TOO_SMALL_BIG_BLOCK(len0)) {
*aligned_dst++ = *aligned_src++;
*aligned_dst++ = *aligned_src++;
*aligned_dst++ = *aligned_src++;
*aligned_dst++ = *aligned_src++;
len0 -= BIG_BLOCK_SIZE;
}
/* Copy one long word at a time if possible. */
while (!TOO_SMALL_LITTLE_BLOCK(len0)) {
*aligned_dst++ = *aligned_src++;
len0 -= LITTLE_BLOCK_SIZE;
}
/* Pick up any residual with a byte copier. */
dst = (char *)aligned_dst;
src = (char *)aligned_src;
}
while (len0--)
*dst++ = *src++;
return dst;
#endif /* not __PREFER_SIZE_OVER_SPEED */
}
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