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/*
Copyright (c) 2007 Corinna Vinschen <corinna@vinschen.de>
*/
/*
FUNCTION
<<stpncpy>>---counted copy string returning a pointer to its end
INDEX
stpncpy
SYNOPSIS
#include <string.h>
char *stpncpy(char *restrict <[dst]>, const char *restrict <[src]>,
size_t <[length]>);
DESCRIPTION
<<stpncpy>> copies not more than <[length]> characters from the
the string pointed to by <[src]> (including the terminating
null character) to the array pointed to by <[dst]>. If the
string pointed to by <[src]> is shorter than <[length]>
characters, null characters are appended to the destination
array until a total of <[length]> characters have been
written.
RETURNS
This function returns a pointer to the end of the destination string,
thus pointing to the trailing '\0', or, if the destination string is
not null-terminated, pointing to dst + n.
PORTABILITY
<<stpncpy>> is a GNU extension, candidate for inclusion into POSIX/SUSv4.
<<stpncpy>> requires no supporting OS subroutines.
QUICKREF
stpncpy gnu
*/
#define _DEFAULT_SOURCE
#include <string.h>
#include <limits.h>
#include "local.h"
/*SUPPRESS 560*/
/*SUPPRESS 530*/
char *
stpncpy(char * __restrict dst, const char * __restrict src, size_t count)
{
char *ret = NULL;
#if !defined(__PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__) \
&& !defined(_PICOLIBC_NO_OUT_OF_BOUNDS_READS)
long *aligned_dst;
const long *aligned_src;
/* If SRC and DEST is aligned and count large enough, then copy words. */
if (!UNALIGNED_X_Y(src, dst) && !TOO_SMALL_LITTLE_BLOCK(count)) {
aligned_dst = (long *)dst;
aligned_src = (long *)src;
/* SRC and DEST are both LITTLE_BLOCK_SIZE aligned,
try to do LITTLE_BLOCK_SIZE sized copies. */
while (!TOO_SMALL_LITTLE_BLOCK(count) && !DETECT_NULL(*aligned_src)) {
count -= LITTLE_BLOCK_SIZE;
*aligned_dst++ = *aligned_src++;
}
dst = (char *)aligned_dst;
src = (char *)aligned_src;
}
#endif /* not __PREFER_SIZE_OVER_SPEED */
while (count > 0) {
--count;
if ((*dst++ = *src++) == '\0') {
ret = dst - 1;
break;
}
}
while (count-- > 0)
*dst++ = '\0';
return ret ? ret : dst;
}
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