src/system/libroot/posix/time/wcsftime.c

   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
  29 #include <errno.h>
  30 #include <stdint.h>
  31 #include <stdlib.h>
  32 #include <time.h>
  33
  34 #include <errno_private.h>
  35 #include <wchar_private.h>
  36
  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 size_t
  52 wcsftime(wchar_t *wcs, size_t maxsize, const wchar_t *format,
  53         const struct tm *timeptr)
  54 {
  55         static const mbstate_t initial;
  56         mbstate_t mbs;
  57         char *dst, *sformat;
  58         const char *dstp;
  59         const wchar_t *formatp;
  60         size_t n, sflen;
  61         int sverrno;
  62
  63         sformat = dst = NULL;
  64
  65         /*
  66          * Convert the supplied format string to a multibyte representation
  67          * for strftime(), which only handles single-byte characters.
  68          */
  69         mbs = initial;
  70         formatp = format;
  71         sflen = __wcsrtombs(NULL, &formatp, 0, &mbs);
  72         if (sflen == (size_t)-1)
  73                 goto error;
  74         if ((sformat = malloc(sflen + 1)) == NULL)
  75                 goto error;
  76         mbs = initial;
  77         __wcsrtombs(sformat, &formatp, sflen + 1, &mbs);
  78
  79         /*
  80          * Allocate memory for longest multibyte sequence that will fit
  81          * into the caller's buffer and call strftime() to fill it.
  82          * Then, copy and convert the result back into wide characters in
  83          * the caller's buffer.
  84          */
  85         if (SIZE_MAX / MB_CUR_MAX <= maxsize) {
  86                 /* maxsize is prepostorously large - avoid int. overflow. */
  87                 __set_errno(EINVAL);
  88                 goto error;
  89         }
  90         if ((dst = malloc(maxsize * MB_CUR_MAX)) == NULL)
  91                 goto error;
  92         if (strftime(dst, maxsize, sformat, timeptr) == 0)
  93                 goto error;
  94         dstp = dst;
  95         mbs = initial;
  96         n = __mbsrtowcs(wcs, &dstp, maxsize, &mbs);
  97         if (n == (size_t)-2 || n == (size_t)-1 || dstp != NULL)
  98                 goto error;
  99
 100         free(sformat);
 101         free(dst);
 102
 103         return n;
 104
 105 error:
 106         sverrno = errno;
 107         free(sformat);
 108         free(dst);
 109         __set_errno(sverrno);
 110
 111         return 0;
 112 }