1/*-
2 * Copyright (c) 2002 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
29#include <errno.h>
30#include <stdint.h>
31#include <stdlib.h>
32#include <time.h>
33
34#include <errno_private.h>
35#include <wchar_private.h>
36
37
38/*
39 * Convert date and time to a wide-character string.
40 *
41 * This is the wide-character counterpart of strftime(). So that we do not
42 * have to duplicate the code of strftime(), we convert the format string to
43 * multibyte, call strftime(), then convert the result back into wide
44 * characters.
45 *
46 * This technique loses in the presence of stateful multibyte encoding if any
47 * of the conversions in the format string change conversion state. When
48 * stateful encoding is implemented, we will need to reset the state between
49 * format specifications in the format string.
50 */
51size_t
52wcsftime(wchar_t *wcs, size_t maxsize, const wchar_t *format,
53	const struct tm *timeptr)
54{
55	static const mbstate_t initial;
56	mbstate_t mbs;
57	char *dst, *sformat;
58	const char *dstp;
59	const wchar_t *formatp;
60	size_t n, sflen;
61	int sverrno;
62
63	sformat = dst = NULL;
64
65	/*
66	 * Convert the supplied format string to a multibyte representation
67	 * for strftime(), which only handles single-byte characters.
68	 */
69	mbs = initial;
70	formatp = format;
71	sflen = __wcsrtombs(NULL, &formatp, 0, &mbs);
72	if (sflen == (size_t)-1)
73		goto error;
74	if ((sformat = malloc(sflen + 1)) == NULL)
75		goto error;
76	mbs = initial;
77	__wcsrtombs(sformat, &formatp, sflen + 1, &mbs);
78
79	/*
80	 * Allocate memory for longest multibyte sequence that will fit
81	 * into the caller's buffer and call strftime() to fill it.
82	 * Then, copy and convert the result back into wide characters in
83	 * the caller's buffer.
84	 */
85	if (SIZE_MAX / MB_CUR_MAX <= maxsize) {
86		/* maxsize is prepostorously large - avoid int. overflow. */
87		__set_errno(EINVAL);
88		goto error;
89	}
90	if ((dst = malloc(maxsize * MB_CUR_MAX)) == NULL)
91		goto error;
92	if (strftime(dst, maxsize, sformat, timeptr) == 0)
93		goto error;
94	dstp = dst;
95	mbs = initial;
96	n = __mbsrtowcs(wcs, &dstp, maxsize, &mbs);
97	if (n == (size_t)-2 || n == (size_t)-1 || dstp != NULL)
98		goto error;
99
100	free(sformat);
101	free(dst);
102
103	return n;
104
105error:
106	sverrno = errno;
107	free(sformat);
108	free(dst);
109	__set_errno(sverrno);
110
111	return 0;
112}
113