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Diffstat (limited to '')
-rw-r--r-- | lib/string/stpecpy.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/lib/string/stpecpy.h b/lib/string/stpecpy.h new file mode 100644 index 0000000..2324baa --- /dev/null +++ b/lib/string/stpecpy.h @@ -0,0 +1,90 @@ +/* + * 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 "attr.h" + + +ATTR_STRING(3) +inline char *stpecpy(char *dst, char *end, const char *restrict src); + + +/* + * SYNOPSIS + * [[gnu::null_terminated_string_arg(3)]] + * 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; + 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; + + return stpcpy(mempcpy(dst, src, dlen), "") + trunc; +} + + +#endif // !HAVE_STPECPY +#endif // include guard |