lib/libc/locale/wcsftime.c

   1 /*-
   2  * Copyright (c) 2002 Tim J. Robbins
   3  * All rights reserved.
   4  *
   5  * Copyright (c) 2011 The FreeBSD Foundation
   6  * All rights reserved.
   7  * Portions of this software were developed by David Chisnall
   8  * under sponsorship from the FreeBSD Foundation.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  * $FreeBSD: head/lib/libc/locale/wcsftime.c 227753 2011-11-20 14:45:42Z theraven $
  32  */
  33
  34
  35 #include <errno.h>
  36 #include <limits.h>
  37 #include <stdlib.h>
  38 #include <time.h>
  39 #include <wchar.h>
  40 #include "xlocale_private.h"
  41
  42 /*
  43  * Convert date and time to a wide-character string.
  44  *
  45  * This is the wide-character counterpart of strftime(). So that we do not
  46  * have to duplicate the code of strftime(), we convert the format string to
  47  * multibyte, call strftime(), then convert the result back into wide
  48  * characters.
  49  *
  50  * This technique loses in the presence of stateful multibyte encoding if any
  51  * of the conversions in the format string change conversion state. When
  52  * stateful encoding is implemented, we will need to reset the state between
  53  * format specifications in the format string.
  54  */
  55 size_t
  56 wcsftime_l(wchar_t * __restrict wcs, size_t maxsize,
  57         const wchar_t * __restrict format, const struct tm * __restrict timeptr,
  58         locale_t locale)
  59 {
  60         static const mbstate_t initial;
  61         mbstate_t mbs;
  62         char *dst, *sformat;
  63         const char *dstp;
  64         const wchar_t *formatp;
  65         size_t n, sflen;
  66         int sverrno;
  67         FIX_LOCALE(locale);
  68
  69         sformat = dst = NULL;
  70
  71         /*
  72          * Convert the supplied format string to a multibyte representation
  73          * for strftime(), which only handles single-byte characters.
  74          */
  75         mbs = initial;
  76         formatp = format;
  77         sflen = wcsrtombs_l(NULL, &formatp, 0, &mbs, locale);
  78         if (sflen == (size_t)-1)
  79                 goto error;
  80         if ((sformat = malloc(sflen + 1)) == NULL)
  81                 goto error;
  82         mbs = initial;
  83         wcsrtombs_l(sformat, &formatp, sflen + 1, &mbs, locale);
  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 <= maxsize) {
  92                 /* maxsize is prepostorously large - avoid int. overflow. */
  93                 errno = EINVAL;
  94                 goto error;
  95         }
  96         if ((dst = malloc(maxsize * MB_CUR_MAX)) == NULL)
  97                 goto error;
  98         if (strftime_l(dst, maxsize, sformat, timeptr, locale) == 0)
  99                 goto error;
 100         dstp = dst;
 101         mbs = initial;
 102         n = mbsrtowcs_l(wcs, &dstp, maxsize, &mbs, locale);
 103         if (n == (size_t)-2 || n == (size_t)-1 || dstp != NULL)
 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 size_t
 118 wcsftime(wchar_t * __restrict wcs, size_t maxsize,
 119         const wchar_t * __restrict format, const struct tm * __restrict timeptr)
 120 {
 121         return wcsftime_l(wcs, maxsize, format, timeptr, __get_locale());
 122 }