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