wcsftime.c revision 302408 
150472Speter/*-
238738Sbrian * Copyright (c) 2002 Tim J. Robbins
33161Sache * All rights reserved.
463912Sasmodai *
5130151Sschweikh * Copyright (c) 2011 The FreeBSD Foundation
63161Sache * All rights reserved.
73161Sache * Portions of this software were developed by David Chisnall
863912Sasmodai * under sponsorship from the FreeBSD Foundation.
963912Sasmodai *
1063912Sasmodai * Redistribution and use in source and binary forms, with or without
114994Sache * modification, are permitted provided that the following conditions
1235121Sdes * are met:
1335121Sdes * 1. Redistributions of source code must retain the above copyright
1463912Sasmodai *    notice, this list of conditions and the following disclaimer.
15208116Sjilles * 2. Redistributions in binary form must reproduce the above copyright
16208116Sjilles *    notice, this list of conditions and the following disclaimer in the
1719033Sache *    documentation and/or other materials provided with the distribution.
1819033Sache *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: stable/11/lib/libc/locale/wcsftime.c 227753 2011-11-20 14:45:42Z theraven $");
34
35#include <errno.h>
36#include <limits.h>
37#include <stdlib.h>
38#include <time.h>
39#include <wchar.h>
40#include "xlocale_private.h"
41
42/*
43 * Convert date and time to a wide-character string.
44 *
45 * This is the wide-character counterpart of strftime(). So that we do not
46 * have to duplicate the code of strftime(), we convert the format string to
47 * multibyte, call strftime(), then convert the result back into wide
48 * characters.
49 *
50 * This technique loses in the presence of stateful multibyte encoding if any
51 * of the conversions in the format string change conversion state. When
52 * stateful encoding is implemented, we will need to reset the state between
53 * format specifications in the format string.
54 */
55size_t
56wcsftime_l(wchar_t * __restrict wcs, size_t maxsize,
57	const wchar_t * __restrict format, const struct tm * __restrict timeptr,
58	locale_t locale)
59{
60	static const mbstate_t initial;
61	mbstate_t mbs;
62	char *dst, *sformat;
63	const char *dstp;
64	const wchar_t *formatp;
65	size_t n, sflen;
66	int sverrno;
67	FIX_LOCALE(locale);
68
69	sformat = dst = NULL;
70
71	/*
72	 * Convert the supplied format string to a multibyte representation
73	 * for strftime(), which only handles single-byte characters.
74	 */
75	mbs = initial;
76	formatp = format;
77	sflen = wcsrtombs_l(NULL, &formatp, 0, &mbs, locale);
78	if (sflen == (size_t)-1)
79		goto error;
80	if ((sformat = malloc(sflen + 1)) == NULL)
81		goto error;
82	mbs = initial;
83	wcsrtombs_l(sformat, &formatp, sflen + 1, &mbs, locale);
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 <= maxsize) {
92		/* maxsize is prepostorously large - avoid int. overflow. */
93		errno = EINVAL;
94		goto error;
95	}
96	if ((dst = malloc(maxsize * MB_CUR_MAX)) == NULL)
97		goto error;
98	if (strftime_l(dst, maxsize, sformat, timeptr, locale) == 0)
99		goto error;
100	dstp = dst;
101	mbs = initial;
102	n = mbsrtowcs_l(wcs, &dstp, maxsize, &mbs, locale);
103	if (n == (size_t)-2 || n == (size_t)-1 || dstp != NULL)
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}
117size_t
118wcsftime(wchar_t * __restrict wcs, size_t maxsize,
119	const wchar_t * __restrict format, const struct tm * __restrict timeptr)
120{
121	return wcsftime_l(wcs, maxsize, format, timeptr, __get_locale());
122}
123