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fgetwc.c revision 1.2 
      1 /* $NetBSD: fgetwc.c,v 1.2 2003/01/18 11:29:51 thorpej Exp $ */
      2 
      3 /*-
      4  * Copyright (c)2001 Citrus Project,
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  *
     28  * $Citrus$
     29  */
     30 
     31 #include <assert.h>
     32 #include <errno.h>
     33 #include <stdio.h>
     34 #include <wchar.h>
     35 #include "reentrant.h"
     36 #include "local.h"
     37 
     38 wint_t
     39 fgetwc(FILE *fp)
     40 {
     41 	struct wchar_io_data *wcio;
     42 	mbstate_t *st;
     43 	wchar_t wc;
     44 	size_t size;
     45 
     46 	_DIAGASSERT(fp != NULL);
     47 
     48 	FLOCKFILE(fp);
     49 	_SET_ORIENTATION(fp, 1);
     50 	wcio = WCIO_GET(fp);
     51 	if (wcio == 0) {
     52 		FUNLOCKFILE(fp);
     53 		errno = ENOMEM;
     54 		return WEOF;
     55 	}
     56 
     57 	/* if there're ungetwc'ed wchars, use them */
     58 	if (wcio->wcio_ungetwc_inbuf) {
     59 		wc = wcio->wcio_ungetwc_buf[--wcio->wcio_ungetwc_inbuf];
     60 		FUNLOCKFILE(fp);
     61 
     62 		return wc;
     63 	}
     64 
     65 	st = &wcio->wcio_mbstate_in;
     66 
     67 	do {
     68 		char c;
     69 		int ch = __sgetc(fp);
     70 
     71 		if (ch == EOF) {
     72 			FUNLOCKFILE(fp);
     73 			return WEOF;
     74 		}
     75 
     76 		c = ch;
     77 		size = mbrtowc(&wc, &c, 1, st);
     78 		if (size == (size_t)-1) {
     79 			FUNLOCKFILE(fp);
     80 			errno = EILSEQ;
     81 			return WEOF;
     82 		}
     83 	} while (size == (size_t)-2);
     84 	FUNLOCKFILE(fp);
     85 
     86 	_DIAGASSERT(size == 1);
     87 
     88 	return wc;
     89 }
     90