fgetwc.c revision 131880 
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 131880 2004-07-09 15:12:10Z 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
39/*
40 * MT-safe version.
41 */
42wint_t
43fgetwc(FILE *fp)
44{
45	wint_t r;
46
47	FLOCKFILE(fp);
48	ORIENT(fp, 1);
49	r = __fgetwc(fp);
50	FUNLOCKFILE(fp);
51
52	return (r);
53}
54
55/*
56 * Non-MT-safe version.
57 */
58wint_t
59__fgetwc(FILE *fp)
60{
61	wchar_t wc;
62	size_t nconv;
63
64	if (fp->_r <= 0 && __srefill(fp))
65		return (WEOF);
66	if (MB_CUR_MAX == 1) {
67		/* Fast path for single-byte encodings. */
68		wc = *fp->_p++;
69		fp->_r--;
70		return (wc);
71	}
72	do {
73		nconv = mbrtowc(&wc, fp->_p, fp->_r, &fp->_extra->mbstate);
74		if (nconv == (size_t)-1)
75			break;
76		else if (nconv == (size_t)-2)
77			continue;
78		else if (nconv == 0) {
79			/*
80			 * Assume that the only valid representation of
81			 * the null wide character is a single null byte.
82			 */
83			fp->_p++;
84			fp->_r--;
85			return (L'\0');
86		} else {
87			fp->_p += nconv;
88			fp->_r -= nconv;
89			return (wc);
90		}
91	} while (__srefill(fp) == 0);
92	fp->_flags |= __SERR;
93	errno = EILSEQ;
94	return (WEOF);
95}
96