xref: /freebsd/lib/libc/stdio/fgetwc.c (revision d6ed810a67fa30e63c4e41b72d7d18da9dfa741b)
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("$FreeBSD$");
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 static __inline wint_t	__fgetwc_nbf(FILE *);
40 
41 /*
42  * Non-MT-safe version.
43  */
44 wint_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  */
64 wint_t
65 fgetwc(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 
77 static __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