StdLib/LibC/Locale/wcsftime.c

   1 /*   $NetBSD: wcsftime.c,v 1.2 2006/10/04 14:19:16 tnozaki 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 #include  <LibConfig.h>
  28 #include  <sys/EfiCdefs.h>
  29 #if defined(LIBC_SCCS) && !defined(lint)
  30 #if 0
  31 __FBSDID("$FreeBSD: src/lib/libc/locale/wcsftime.c,v 1.4 2004/04/07 09:47:56 tjr Exp $");
  32 #else
  33 __RCSID("$NetBSD: wcsftime.c,v 1.2 2006/10/04 14:19:16 tnozaki Exp $");
  34 #endif
  35 #endif /* LIBC_SCCS and not lint */
  36
  37 #include <errno.h>
  38 #include <limits.h>
  39 #include <stdlib.h>
  40 #include <time.h>
  41 #include <wchar.h>
  42 #include  <machine/int_limits.h>
  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   char *dst, *dstp, *sformat;
  62   size_t n, sflen;
  63   int sverrno;
  64
  65   sformat = dst = NULL;
  66
  67   /*
  68    * Convert the supplied format string to a multibyte representation
  69    * for strftime(), which only handles single-byte characters.
  70    */
  71   sflen = wcstombs(NULL, format, 0);
  72   if (sflen == (size_t)-1)
  73     goto error;
  74   if ((sformat = malloc(sflen + 1)) == NULL)
  75     goto error;
  76   wcstombs(sformat, format, sflen + 1);
  77
  78   /*
  79    * Allocate memory for longest multibyte sequence that will fit
  80    * into the caller's buffer and call strftime() to fill it.
  81    * Then, copy and convert the result back into wide characters in
  82    * the caller's buffer.
  83    */
  84   if (SIZE_T_MAX / MB_CUR_MAX <= maxsize) {
  85     /* maxsize is preposturously large - avoid int. overflow. */
  86     errno = EINVAL;
  87     goto error;
  88   }
  89   dst = malloc(maxsize * MB_CUR_MAX);
  90   if (dst == NULL)
  91     goto error;
  92   if (strftime(dst, maxsize, sformat, timeptr) == 0)
  93     goto error;
  94   dstp = dst;
  95   n = mbstowcs(wcs, dstp, maxsize);
  96   if (n == (size_t)-2 || n == (size_t)-1)
  97     goto error;
  98
  99   free(sformat);
 100   free(dst);
 101   return n;
 102
 103 error:
 104   sverrno = errno;
 105   free(sformat);
 106   free(dst);
 107   errno = sverrno;
 108   return 0;
 109 }