mbrtowc.c revision 106725 
1/*-
2 * Copyright (c) 2002 Tim J. Robbins.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/lib/libc/locale/mbrtowc.c 106725 2002-11-10 10:49:14Z tjr $");
29
30#include <errno.h>
31#include <rune.h>
32#include <stdlib.h>
33#include <wchar.h>
34
35size_t
36mbrtowc(wchar_t * __restrict pwc, const char * __restrict s, size_t n,
37    mbstate_t * __restrict ps __unused)
38{
39        const char *e;
40        rune_t r;
41
42	if (s == NULL) {
43		pwc = NULL;
44		s = "";
45		n = 1;
46	}
47
48	if ((r = sgetrune(s, n, &e)) == _INVALID_RUNE) {
49		/*
50		 * The design of sgetrune() doesn't give us any way to tell
51		 * between incomplete and invalid multibyte sequences.
52		 */
53
54		if (n >= (size_t)MB_CUR_MAX) {
55			/*
56			 * If we have been supplied with at least MB_CUR_MAX
57			 * bytes and still cannot find a valid character, the
58			 * data must be invalid.
59			 */
60			errno = EILSEQ;
61			return ((size_t)-1);
62		}
63
64		/*
65		 * .. otherwise, it's an incomplete character or an invalid
66		 * character we cannot detect yet.
67		 */
68		return ((size_t)-2);
69	}
70
71	if (pwc != NULL)
72		*pwc = (wchar_t)r;
73
74	return (r != 0 ? (size_t)(e - s) : 0);
75}
76