freebsd-dev/lib/libc/locale/wcsftime.c
Tim J. Robbins 528bebffb1 Use the heap instead of the stack to store temporary multibyte string
buffers; this is slower but safer for threaded programs where threads
often have relatively low stack size limits.
2002-09-15 08:06:17 +00:00

106 lines
3.4 KiB
C

/*-
* Copyright (c) 2002 Tim J. Robbins
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <time.h>
#include <wchar.h>
/*
* Convert date and time to a wide-character string.
*
* This is the wide-character counterpart of strftime(). So that we do not
* have to duplicate the code of strftime(), we convert the format string to
* multibyte, call strftime(), then convert the result back into wide
* characters.
*
* This technique loses in the presence of stateful multibyte encoding if any
* of the conversions in the format string change conversion state. When
* stateful encoding is implemented, we will need to reset the state between
* format specifications in the format string.
*/
size_t
wcsftime(wchar_t * __restrict wcs, size_t maxsize,
const wchar_t * __restrict format, const struct tm * __restrict timeptr)
{
static const mbstate_t initial;
mbstate_t state;
char *dst, *dstp, *sformat;
size_t n, sflen;
int sverrno;
sformat = dst = NULL;
/*
* Convert the supplied format string to a multibyte representation
* for strftime(), which only handles single-byte characters.
*/
state = initial;
sflen = wcsrtombs(NULL, &format, 0, &state);
if (sflen == (size_t)-1)
goto error;
if ((sformat = malloc(sflen + 1)) == NULL)
goto error;
state = initial;
wcsrtombs(sformat, &format, sflen + 1, &state);
/*
* Allocate memory for longest multibyte sequence that will fit
* into the caller's buffer and call strftime() to fill it.
* Then, copy and convert the result back into wide characters in
* the caller's buffer.
*/
if (SIZE_T_MAX / MB_CUR_MAX <= maxsize) {
/* maxsize is prepostorously large - avoid int. overflow. */
errno = EINVAL;
goto error;
}
if ((dst = malloc(maxsize * MB_CUR_MAX)) == NULL)
goto error;
if (strftime(dst, maxsize, sformat, timeptr) == 0)
goto error;
state = initial;
dstp = dst;
n = mbsrtowcs(wcs, (const char **)&dstp, maxsize, &state);
if (n == (size_t)-2 || n == (size_t)-1 || dstp != NULL)
goto error;
free(sformat);
free(dst);
return (n);
error:
sverrno = errno;
free(sformat);
free(dst);
errno = sverrno;
return (0);
}