wcsftime.c revision 1.1 
1/*	 $NetBSD: wcsftime.c,v 1.1 2005/03/30 03:47:12 christos Exp $	*/
2/*-
3 * Copyright (c) 2002 Tim J. Robbins
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29#if defined(LIBC_SCCS) && !defined(lint)
30#if 0
31__FBSDID("$FreeBSD: src/lib/libc/locale/wcsftime.c,v 1.4 2004/04/07 09:47:56 tjr Exp $");
32#else
33__RCSID("$NetBSD: wcsftime.c,v 1.1 2005/03/30 03:47:12 christos Exp $");
34#endif
35#endif /* LIBC_SCCS and not lint */
36
37#include <errno.h>
38#include <limits.h>
39#include <stdlib.h>
40#include <time.h>
41#include <wchar.h>
42
43/*
44 * Convert date and time to a wide-character string.
45 *
46 * This is the wide-character counterpart of strftime(). So that we do not
47 * have to duplicate the code of strftime(), we convert the format string to
48 * multibyte, call strftime(), then convert the result back into wide
49 * characters.
50 *
51 * This technique loses in the presence of stateful multibyte encoding if any
52 * of the conversions in the format string change conversion state. When
53 * stateful encoding is implemented, we will need to reset the state between
54 * format specifications in the format string.
55 */
56size_t
57wcsftime(wchar_t *wcs, size_t maxsize,
58    const wchar_t *format, const struct tm *timeptr)
59{
60	static const mbstate_t initial;
61	mbstate_t mbs;
62	char *dst, *dstp, *sformat;
63	size_t n, sflen;
64	int sverrno;
65
66	sformat = dst = NULL;
67
68	/*
69	 * Convert the supplied format string to a multibyte representation
70	 * for strftime(), which only handles single-byte characters.
71	 */
72	mbs = initial;
73	sflen = wcsrtombs(NULL, &format, 0, &mbs);
74	if (sflen == (size_t)-1)
75		goto error;
76	if ((sformat = malloc(sflen + 1)) == NULL)
77		goto error;
78	mbs = initial;
79	wcsrtombs(sformat, &format, sflen + 1, &mbs);
80
81	/*
82	 * Allocate memory for longest multibyte sequence that will fit
83	 * into the caller's buffer and call strftime() to fill it.
84	 * Then, copy and convert the result back into wide characters in
85	 * the caller's buffer.
86	 */
87	if (SIZE_T_MAX / MB_CUR_MAX <= maxsize) {
88		/* maxsize is preposturously large - avoid int. overflow. */
89		errno = EINVAL;
90		goto error;
91	}
92	if ((dst = malloc(maxsize * MB_CUR_MAX)) == NULL)
93		goto error;
94	if (strftime(dst, maxsize, sformat, timeptr) == 0)
95		goto error;
96	dstp = dst;
97	mbs = initial;
98	n = mbsrtowcs(wcs, (const char **)&dstp, maxsize, &mbs);
99	if (n == (size_t)-2 || n == (size_t)-1 || dstp != NULL)
100		goto error;
101
102	free(sformat);
103	free(dst);
104	return n;
105
106error:
107	sverrno = errno;
108	free(sformat);
109	free(dst);
110	errno = sverrno;
111	return 0;
112}
113