xref: /illumos-gate/usr/src/lib/libc/port/locale/btowc.c (revision 75eba5b6d79ed4d2ce3daf7b2806306b6b69a938)
1 /*
2  * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
3  * Copyright (c) 2002, 2003 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 <stdio.h>
30 #include <wchar.h>
31 #include "mblocal.h"
32 
33 wint_t
34 btowc(int c)
35 {
36 	static const mbstate_t initial = { 0 };
37 	mbstate_t mbs = initial;
38 	char cc;
39 	wchar_t wc;
40 
41 	if (c == EOF)
42 		return (WEOF);
43 	/*
44 	 * We expect mbrtowc() to return 0 or 1, hence the check for n > 1
45 	 * which detects error return values as well as "impossible" byte
46 	 * counts.
47 	 */
48 	cc = (char)c;
49 	if (__mbrtowc(&wc, &cc, 1, &mbs) > 1)
50 		return (WEOF);
51 	return (wc);
52 }
53