xref: /titanic_41/usr/src/lib/libc/port/locale/wcsftime.c (revision 430b4c467020edf2445feb0c21db01c88b86243a)
1 /*
2  * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
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 "lint.h"
29 #include "mse_int.h"
30 #include <errno.h>
31 #include <limits.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <time.h>
35 #include <wchar.h>
36 #include <alloca.h>
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  *
51  * Note carefully that prior to xpg5, the format was char *, not wchar_t.
52  */
53 
54 /*
55  * Hmmm this is probably a bit backwards.  As we are converting to single
56  * byte formats, perhaps we should not be doing a redundant conversion.
57  * Something to look at for the future.
58  */
59 
60 size_t
61 __wcsftime_xpg5(wchar_t *wcs, size_t maxsize, const wchar_t *format,
62     const struct tm *timeptr)
63 {
64 	static const mbstate_t initial = { 0 };
65 	mbstate_t mbs;
66 	char *dst, *sformat;
67 	const char *dstp;
68 	const wchar_t *formatp;
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 	mbs = initial;
79 	formatp = format;
80 	sflen = wcsrtombs(NULL, &formatp, 0, &mbs);
81 	if (sflen == (size_t)-1)
82 		goto error;
83 	if ((sformat = malloc(sflen + 1)) == NULL)
84 		goto error;
85 	mbs = initial;
86 	(void) wcsrtombs(sformat, &formatp, sflen + 1, &mbs);
87 
88 	/*
89 	 * Allocate memory for longest multibyte sequence that will fit
90 	 * into the caller's buffer and call strftime() to fill it.
91 	 * Then, copy and convert the result back into wide characters in
92 	 * the caller's buffer.
93 	 */
94 	if (LONG_MAX / MB_CUR_MAX <= maxsize) {
95 		/* maxsize is prepostorously large - avoid int. overflow. */
96 		errno = EINVAL;
97 		goto error;
98 	}
99 	if ((dst = malloc(maxsize * MB_CUR_MAX)) == NULL)
100 		goto error;
101 	if (strftime(dst, maxsize, sformat, timeptr) == 0)
102 		goto error;
103 	dstp = dst;
104 	mbs = initial;
105 	n = mbsrtowcs(wcs, &dstp, maxsize, &mbs);
106 	if (n == (size_t)-2 || n == (size_t)-1 || dstp != NULL)
107 		goto error;
108 
109 	free(sformat);
110 	free(dst);
111 	return (n);
112 
113 error:
114 	sverrno = errno;
115 	free(sformat);
116 	free(dst);
117 	errno = sverrno;
118 	return (0);
119 }
120 
121 size_t
122 wcsftime(wchar_t *wcs, size_t maxsize, const char *format,
123     const struct tm *timeptr)
124 {
125 	int	len;
126 	wchar_t	*wfmt;
127 	size_t rv;
128 
129 	/* Convert the format (mb string) to wide char array */
130 	len = strlen(format) + 1;
131 	wfmt = malloc(sizeof (wchar_t) * len);
132 	if (mbstowcs(wfmt, format, len) == (size_t)-1) {
133 		free(wfmt);
134 		return (0);
135 	}
136 	rv = __wcsftime_xpg5(wcs, maxsize, wfmt, timeptr);
137 	free(wfmt);
138 	return (rv);
139 }
140