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// SPDX-FileCopyrightText: 2022-2024, Alejandro Colomar <alx@kernel.org>
// SPDX-License-Identifier: BSD-3-Clause
#ifndef SHADOW_INCLUDE_LIB_STRING_ZUSTR2STP_H_
#define SHADOW_INCLUDE_LIB_STRING_ZUSTR2STP_H_
#include <config.h>
#include <assert.h>
#include <string.h>
#include "must_be.h"
#include "sizeof.h"
/*
* SYNOPSIS
* char *ZUSTR2STP(char *restrict dst, const char src[restrict]);
*
* ARGUMENTS
* dst Destination buffer.
* src Source null-padded character sequence.
*
* DESCRIPTION
* This macro copies at most NITEMS(src) non-null bytes from the
* array pointed to by src, followed by a null character, to the
* buffer pointed to by dst.
*
* RETURN VALUE
* dst + strlen(dst)
* This function returns a pointer to the terminating NUL
* byte.
*
* CAVEATS
* This function doesn't know the size of the destination buffer.
* It assumes it will always be large enough. Since the size of
* the source buffer is known to the caller, it should make sure to
* allocate a destination buffer of at least `NITEMS(src) + 1`.
*
* EXAMPLES
* char hostname[NITEMS(utmp->ut_host) + 1];
*
* len = ZUSTR2STP(hostname, utmp->ut_host) - hostname;
* puts(hostname);
*/
#define ZUSTR2STP(dst, src) \
({ \
static_assert(!is_array(dst) || sizeof(dst) > SIZEOF_ARRAY(src), ""); \
\
stpcpy(mempcpy(dst, src, strnlen(src, NITEMS(src))), ""); \
})
#endif // include guard
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