1/*	 $NetBSD: wcsftime.c,v 1.2 2006/10/04 14:19:16 tnozaki 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 1.2 2006/10/04 14:19:16 tnozaki 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	char *dst, *dstp, *sformat;
61	size_t n, sflen;
62	int sverrno;
63
64	sformat = dst = NULL;
65
66	/*
67	 * Convert the supplied format string to a multibyte representation
68	 * for strftime(), which only handles single-byte characters.
69	 */
70	sflen = wcstombs(NULL, format, 0);
71	if (sflen == (size_t)-1)
72		goto error;
73	if ((sformat = malloc(sflen + 1)) == NULL)
74		goto error;
75	wcstombs(sformat, format, sflen + 1);
76
77	/*
78	 * Allocate memory for longest multibyte sequence that will fit
79	 * into the caller's buffer and call strftime() to fill it.
80	 * Then, copy and convert the result back into wide characters in
81	 * the caller's buffer.
82	 */
83	if (SIZE_T_MAX / MB_CUR_MAX <= maxsize) {
84		/* maxsize is preposterously large - avoid int. overflow. */
85		errno = EINVAL;
86		goto error;
87	}
88	dst = malloc(maxsize * MB_CUR_MAX);
89	if (dst == NULL)
90		goto error;
91	if (strftime(dst, maxsize, sformat, timeptr) == 0)
92		goto error;
93	dstp = dst;
94	n = mbstowcs(wcs, dstp, maxsize);
95	if (n == (size_t)-2 || n == (size_t)-1)
96		goto error;
97
98	free(sformat);
99	free(dst);
100	return n;
101
102error:
103	sverrno = errno;
104	free(sformat);
105	free(dst);
106	errno = sverrno;
107	return 0;
108}
109