shadow/lib/stpecpy.h

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/*
* SPDX-FileCopyrightText: 2022 - 2023, Alejandro Colomar <alx@kernel.org>
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef SHADOW_INCLUDE_LIB_STPECPY_H_
#define SHADOW_INCLUDE_LIB_STPECPY_H_
#include <config.h>
#if !defined(HAVE_STPECPY)
#include <stdbool.h>
#include <stddef.h>
#include <string.h>
#include "defines.h"
inline char *stpecpy(char *dst, char *end, const char *restrict src);
/*
* SYNOPSIS
* char *_Nullable stpecpy(char *_Nullable dst, char end[0],
* const char *restrict src);
*
* ARGUMENTS
* dst Destination buffer where to copy a string.
*
* end Pointer to one after the last element of the buffer
* pointed to by `dst`. Usually, it should be calculated
* as `dst + NITEMS(dst)`.
*
* src Source string to be copied into dst.
*
* DESCRIPTION
* This function copies the string pointed to by src, into a string
* at the buffer pointed to by dst. If the destination buffer,
* limited by a pointer to its end --one after its last element--,
* isn't large enough to hold the copy, the resulting string is
* truncated.
*
* This function can be chained with calls to [v]stpeprintf().
*
* RETURN VALUE
* dst + strlen(dst)
* On success, this function returns a pointer to the
* terminating NUL byte.
*
* end
* If this call truncated the resulting string.
* If `dst == end` (a previous chained call to these
* functions truncated).
* NULL
* If `dst == NULL` (a previous chained call to
* [v]stpeprintf() failed).
*
* ERRORS
* This function doesn't set errno.
*/
inline char *
stpecpy(char *dst, char *end, const char *restrict src)
{
bool trunc;
char *p;
size_t dsize, dlen, slen;
if (dst == end)
return end;
if (dst == NULL)
return NULL;
dsize = end - dst;
slen = strnlen(src, dsize);
trunc = (slen == dsize);
dlen = slen - trunc;
p = mempcpy(dst, src, dlen);
*p = '\0';
return p + trunc;
}
#endif // !HAVE_STPECPY
#endif // include guard