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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 __FBSDID("$FreeBSD: src/lib/libc/locale/wcsftime.c,v 1.6 2009/01/15 20:45:59 rdivacky Exp $");
29
30 #include <errno.h>
31 #include <limits.h>
32 #include <stdlib.h>
33 #include <time.h>
34 #include <wchar.h>
35
36 /*
37 * Convert date and time to a wide-character string.
38 *
39 * This is the wide-character counterpart of strftime(). So that we do not
40 * have to duplicate the code of strftime(), we convert the format string to
41 * multibyte, call strftime(), then convert the result back into wide
42 * characters.
43 *
44 * This technique loses in the presence of stateful multibyte encoding if any
45 * of the conversions in the format string change conversion state. When
46 * stateful encoding is implemented, we will need to reset the state between
47 * format specifications in the format string.
48 */
49 size_t
50 wcsftime(wchar_t * __restrict wcs, size_t maxsize,
51 const wchar_t * __restrict format, const struct tm * __restrict timeptr)
52 {
53 static const mbstate_t initial;
54 mbstate_t mbs;
55 char *dst, *sformat;
56 const char *dstp;
57 const wchar_t *formatp;
58 size_t n, sflen;
59 int sverrno;
60
61 sformat = dst = NULL;
62
63 /*
64 * Convert the supplied format string to a multibyte representation
65 * for strftime(), which only handles single-byte characters.
66 */
67 mbs = initial;
68 formatp = format;
69 sflen = wcsrtombs(NULL, &formatp, 0, &mbs);
70 if (sflen == (size_t)-1)
71 goto error;
72 if ((sformat = malloc(sflen + 1)) == NULL)
73 goto error;
74 mbs = initial;
75 wcsrtombs(sformat, &formatp, sflen + 1, &mbs);
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 prepostorously large - avoid int. overflow. */
85 errno = EINVAL;
86 goto error;
87 }
88 if ((dst = malloc(maxsize * MB_CUR_MAX)) == NULL)
89 goto error;
90 if (strftime(dst, maxsize, sformat, timeptr) == 0)
91 goto error;
92 dstp = dst;
93 mbs = initial;
94 n = mbsrtowcs(wcs, &dstp, maxsize, &mbs);
95 if (n == (size_t)-2 || n == (size_t)-1 || dstp != NULL)
96 goto error;
97
98 free(sformat);
99 free(dst);
100 return (n);
101
102 error:
103 sverrno = errno;
104 free(sformat);
105 free(dst);
106 errno = sverrno;
107 return (0);
108 }