lib/libc/locale/wcsftime.c

   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
  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
  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 }