usr/src/lib/libc/port/locale/wcsftime.c

   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 }