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 __FBSDID("$FreeBSD$"); 29 30 #include <errno.h> 31 #include <limits.h> 32 #include <stdlib.h> 33 #include <time.h> 34 #include <wchar.h> 35 36 /* 37 * Convert date and time to a wide-character string. 38 * 39 * This is the wide-character counterpart of strftime(). So that we do not 40 * have to duplicate the code of strftime(), we convert the format string to 41 * multibyte, call strftime(), then convert the result back into wide 42 * characters. 43 * 44 * This technique loses in the presence of stateful multibyte encoding if any 45 * of the conversions in the format string change conversion state. When 46 * stateful encoding is implemented, we will need to reset the state between 47 * format specifications in the format string. 48 */ 49 size_t 50 wcsftime(wchar_t * __restrict wcs, size_t maxsize, 51 const wchar_t * __restrict format, const struct tm * __restrict timeptr) 52 { 53 static const mbstate_t initial; 54 mbstate_t mbs; 55 char *dst, *dstp, *sformat; 56 size_t n, sflen; 57 int sverrno; 58 59 sformat = dst = NULL; 60 61 /* 62 * Convert the supplied format string to a multibyte representation 63 * for strftime(), which only handles single-byte characters. 64 */ 65 mbs = initial; 66 sflen = wcsrtombs(NULL, &format, 0, &mbs); 67 if (sflen == (size_t)-1) 68 goto error; 69 if ((sformat = malloc(sflen + 1)) == NULL) 70 goto error; 71 mbs = initial; 72 wcsrtombs(sformat, &format, sflen + 1, &mbs); 73 74 /* 75 * Allocate memory for longest multibyte sequence that will fit 76 * into the caller's buffer and call strftime() to fill it. 77 * Then, copy and convert the result back into wide characters in 78 * the caller's buffer. 79 */ 80 if (SIZE_T_MAX / MB_CUR_MAX <= maxsize) { 81 /* maxsize is prepostorously large - avoid int. overflow. */ 82 errno = EINVAL; 83 goto error; 84 } 85 if ((dst = malloc(maxsize * MB_CUR_MAX)) == NULL) 86 goto error; 87 if (strftime(dst, maxsize, sformat, timeptr) == 0) 88 goto error; 89 dstp = dst; 90 mbs = initial; 91 n = mbsrtowcs(wcs, (const char **)&dstp, maxsize, &mbs); 92 if (n == (size_t)-2 || n == (size_t)-1 || dstp != NULL) 93 goto error; 94 95 free(sformat); 96 free(dst); 97 return (n); 98 99 error: 100 sverrno = errno; 101 free(sformat); 102 free(dst); 103 errno = sverrno; 104 return (0); 105 } 106