fgetwc.c revision 132442 
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 132442 2004-07-20 08:27:27Z 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#include "mblocal.h"
39
40/*
41 * MT-safe version.
42 */
43wint_t
44fgetwc(FILE *fp)
45{
46	wint_t r;
47
48	FLOCKFILE(fp);
49	ORIENT(fp, 1);
50	r = __fgetwc(fp);
51	FUNLOCKFILE(fp);
52
53	return (r);
54}
55
56/*
57 * Non-MT-safe version.
58 */
59wint_t
60__fgetwc(FILE *fp)
61{
62	wchar_t wc;
63	size_t nconv;
64
65	if (fp->_r <= 0 && __srefill(fp))
66		return (WEOF);
67	if (MB_CUR_MAX == 1) {
68		/* Fast path for single-byte encodings. */
69		wc = *fp->_p++;
70		fp->_r--;
71		return (wc);
72	}
73	do {
74		nconv = __mbrtowc(&wc, fp->_p, fp->_r, &fp->_extra->mbstate);
75		if (nconv == (size_t)-1)
76			break;
77		else if (nconv == (size_t)-2)
78			continue;
79		else if (nconv == 0) {
80			/*
81			 * Assume that the only valid representation of
82			 * the null wide character is a single null byte.
83			 */
84			fp->_p++;
85			fp->_r--;
86			return (L'\0');
87		} else {
88			fp->_p += nconv;
89			fp->_r -= nconv;
90			return (wc);
91		}
92	} while (__srefill(fp) == 0);
93	fp->_flags |= __SERR;
94	errno = EILSEQ;
95	return (WEOF);
96}
97