wcsftime.c revision 1.4 
1/*	 $NetBSD: wcsftime.c,v 1.4 2013/08/19 08:03:34 joerg 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__RCSID("$NetBSD: wcsftime.c,v 1.4 2013/08/19 08:03:34 joerg Exp $");
30
31#define __SETLOCALE_SOURCE__
32#include "namespace.h"
33#include <errno.h>
34#include <limits.h>
35#include <locale.h>
36#include <stdlib.h>
37#include <time.h>
38#include <wchar.h>
39
40#include "setlocale_local.h"
41
42__weak_alias(wcsftime_l, _wcsftime_l)
43
44/*
45 * Convert date and time to a wide-character string.
46 *
47 * This is the wide-character counterpart of strftime(). So that we do not
48 * have to duplicate the code of strftime(), we convert the format string to
49 * multibyte, call strftime(), then convert the result back into wide
50 * characters.
51 *
52 * This technique loses in the presence of stateful multibyte encoding if any
53 * of the conversions in the format string change conversion state. When
54 * stateful encoding is implemented, we will need to reset the state between
55 * format specifications in the format string.
56 */
57size_t
58wcsftime(wchar_t *wcs, size_t maxsize,
59    const wchar_t *format, const struct tm *timeptr)
60{
61	return wcsftime_l(wcs, maxsize, format, timeptr, _current_locale());
62}
63
64size_t
65wcsftime_l(wchar_t *wcs, size_t maxsize,
66    const wchar_t *format, const struct tm *timeptr, locale_t loc)
67{
68	char *dst, *dstp, *sformat;
69	size_t n, sflen;
70	int sverrno;
71
72	sformat = dst = NULL;
73
74	/*
75	 * Convert the supplied format string to a multibyte representation
76	 * for strftime(), which only handles single-byte characters.
77	 */
78	sflen = wcstombs_l(NULL, format, 0, loc);
79	if (sflen == (size_t)-1)
80		goto error;
81	if ((sformat = malloc(sflen + 1)) == NULL)
82		goto error;
83	wcstombs_l(sformat, format, sflen + 1, loc);
84
85	/*
86	 * Allocate memory for longest multibyte sequence that will fit
87	 * into the caller's buffer and call strftime() to fill it.
88	 * Then, copy and convert the result back into wide characters in
89	 * the caller's buffer.
90	 */
91	if (SIZE_T_MAX / MB_CUR_MAX_L(loc) <= maxsize) {
92		/* maxsize is preposterously large - avoid int. overflow. */
93		errno = EINVAL;
94		goto error;
95	}
96	dst = malloc(maxsize * MB_CUR_MAX);
97	if (dst == NULL)
98		goto error;
99	if (strftime_l(dst, maxsize, sformat, timeptr, loc) == 0)
100		goto error;
101	dstp = dst;
102	n = mbstowcs_l(wcs, dstp, maxsize, loc);
103	if (n == (size_t)-2 || n == (size_t)-1)
104		goto error;
105
106	free(sformat);
107	free(dst);
108	return n;
109
110error:
111	sverrno = errno;
112	free(sformat);
113	free(dst);
114	errno = sverrno;
115	return 0;
116}
117