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freebsd/lib/libc/locale/mbrtowc.c
Tim J. Robbins 2f5154a2c1 Don't check whether the first byte of the buffer is a null byte when
the buffer has zero length (n == 0).
2002-11-10 10:49:14 +00:00

76 lines
2.3 KiB
C

/*-
* Copyright (c) 2002 Tim J. Robbins.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <errno.h>
#include <rune.h>
#include <stdlib.h>
#include <wchar.h>
size_t
mbrtowc(wchar_t * __restrict pwc, const char * __restrict s, size_t n,
mbstate_t * __restrict ps __unused)
{
const char *e;
rune_t r;
if (s == NULL) {
pwc = NULL;
s = "";
n = 1;
}
if ((r = sgetrune(s, n, &e)) == _INVALID_RUNE) {
/*
* The design of sgetrune() doesn't give us any way to tell
* between incomplete and invalid multibyte sequences.
*/
if (n >= (size_t)MB_CUR_MAX) {
/*
* If we have been supplied with at least MB_CUR_MAX
* bytes and still cannot find a valid character, the
* data must be invalid.
*/
errno = EILSEQ;
return ((size_t)-1);
}
/*
* .. otherwise, it's an incomplete character or an invalid
* character we cannot detect yet.
*/
return ((size_t)-2);
}
if (pwc != NULL)
*pwc = (wchar_t)r;
return (r != 0 ? (size_t)(e - s) : 0);
}