mbrtowc.c revision 121845 
1/*-
2 * Copyright (c) 2002, 2003 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 121845 2003-11-01 05:13:13Z tjr $");
29
30#include <errno.h>
31#include <rune.h>
32#include <stdlib.h>
33#include <wchar.h>
34
35extern size_t (*__mbrtowc)(wchar_t * __restrict, const char * __restrict,
36    size_t, mbstate_t * __restrict);
37
38size_t
39mbrtowc(wchar_t * __restrict pwc, const char * __restrict s,
40    size_t n, mbstate_t * __restrict ps)
41{
42
43	return (__mbrtowc(pwc, s, n, ps));
44}
45
46/*
47 * Emulate the ISO C mbrtowc() function in terms of the deprecated
48 * 4.4BSD sgetrune() function.
49 */
50size_t
51__emulated_mbrtowc(wchar_t * __restrict pwc, const char * __restrict s,
52    size_t n, mbstate_t * __restrict ps __unused)
53{
54        const char *e;
55        rune_t r;
56
57	if (s == NULL) {
58		pwc = NULL;
59		s = "";
60		n = 1;
61	}
62
63	if ((r = sgetrune(s, n, &e)) == _INVALID_RUNE) {
64		/*
65		 * The design of sgetrune() doesn't give us any way to tell
66		 * between incomplete and invalid multibyte sequences.
67		 */
68
69		if (n >= (size_t)MB_CUR_MAX) {
70			/*
71			 * If we have been supplied with at least MB_CUR_MAX
72			 * bytes and still cannot find a valid character, the
73			 * data must be invalid.
74			 */
75			errno = EILSEQ;
76			return ((size_t)-1);
77		}
78
79		/*
80		 * .. otherwise, it's an incomplete character or an invalid
81		 * character we cannot detect yet.
82		 */
83		return ((size_t)-2);
84	}
85
86	if (pwc != NULL)
87		*pwc = (wchar_t)r;
88
89	return (r != 0 ? (size_t)(e - s) : 0);
90}
91