locale/FreeBSD/mbrtowc.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 __FBSDID("$FreeBSD: src/lib/libc/locale/mbrtowc.c,v 1.3 2002/11/10 10:49:14 tjr Exp $");
  29
  30 #include <errno.h>
  31 #include <rune.h>
  32 #include <stdlib.h>
  33 #include <wchar.h>
  34
  35 size_t
  36 mbrtowc(wchar_t * __restrict pwc, const char * __restrict s, size_t n,
  37     mbstate_t * __restrict ps __unused)
  38 {
  39         const char *e;
  40         rune_t r;
  41
  42         if (s == NULL) {
  43                 pwc = NULL;
  44                 s = "";
  45                 n = 1;
  46         }
  47
  48         if ((r = sgetrune(s, n, &e)) == _INVALID_RUNE) {
  49                 /*
  50                  * The design of sgetrune() doesn't give us any way to tell
  51                  * between incomplete and invalid multibyte sequences.
  52                  */
  53
  54                 if (n >= (size_t)MB_CUR_MAX) {
  55                         /*
  56                          * If we have been supplied with at least MB_CUR_MAX
  57                          * bytes and still cannot find a valid character, the
  58                          * data must be invalid.
  59                          */
  60                         errno = EILSEQ;
  61                         return ((size_t)-1);
  62                 }
  63
  64                 /*
  65                  * .. otherwise, it's an incomplete character or an invalid
  66                  * character we cannot detect yet.
  67                  */
  68                 return ((size_t)-2);
  69         }
  70
  71         if (pwc != NULL)
  72                 *pwc = (wchar_t)r;
  73
  74         return (r != 0 ? (size_t)(e - s) : 0);
  75 }