fgetwc.c revision 129584 
1/*-
2 * Copyright (c) 2002-2004 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: head/lib/libc/stdio/fgetwc.c 129584 2004-05-22 15:41:03Z tjr $");
29
30#include "namespace.h"
31#include <errno.h>
32#include <stdio.h>
33#include <stdlib.h>
34#include <wchar.h>
35#include "un-namespace.h"
36#include "libc_private.h"
37#include "local.h"
38
39static __inline wint_t	__fgetwc_nbf(FILE *);
40
41/*
42 * Non-MT-safe version.
43 */
44wint_t
45__fgetwc(FILE *fp)
46{
47	wint_t wc;
48
49	if (MB_CUR_MAX == 1) {
50		/*
51		 * Assume we're using a single-byte locale. A safer test
52		 * might be to check _CurrentRuneLocale->encoding.
53		 */
54		wc = (wint_t)__sgetc(fp);
55	} else
56		wc = __fgetwc_nbf(fp);
57
58	return (wc);
59}
60
61/*
62 * MT-safe version.
63 */
64wint_t
65fgetwc(FILE *fp)
66{
67	wint_t r;
68
69	FLOCKFILE(fp);
70	ORIENT(fp, 1);
71	r = __fgetwc(fp);
72	FUNLOCKFILE(fp);
73
74	return (r);
75}
76
77static __inline wint_t
78__fgetwc_nbf(FILE *fp)
79{
80	wchar_t wc;
81	size_t nconv;
82
83	if (fp->_r <= 0 && __srefill(fp))
84		return (WEOF);
85	do {
86		nconv = mbrtowc(&wc, fp->_p, fp->_r, &fp->_extra->mbstate);
87		if (nconv == (size_t)-1)
88			break;
89		else if (nconv == (size_t)-2)
90			continue;
91		else if (nconv == 0) {
92			/*
93			 * Assume that the only valid representation of
94			 * the null wide character is a single null byte.
95			 */
96			fp->_p++;
97			fp->_r--;
98			return (L'\0');
99		} else {
100			fp->_p += nconv;
101			fp->_r -= nconv;
102			return (wc);
103		}
104	} while (__srefill(fp) == 0);
105	fp->_flags |= __SERR;
106	errno = EILSEQ;
107	return (WEOF);
108}
109