xref: /netbsd/lib/libc/locale/wcsftime.c (revision a94e97a5)
1 /*	 $NetBSD: wcsftime.c,v 1.5 2013/08/19 20:41:15 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 1.5 2013/08/19 20:41:15 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 
__weak_alias(wcsftime_l,_wcsftime_l)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  */
57 size_t
58 wcsftime(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 
64 size_t
wcsftime_l(wchar_t * wcs,size_t maxsize,const wchar_t * format,const struct tm * timeptr,locale_t loc)65 wcsftime_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_L(loc));
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 
110 error:
111 	sverrno = errno;
112 	free(sformat);
113 	free(dst);
114 	errno = sverrno;
115 	return 0;
116 }
117