xref: /freebsd/lib/libc/stdio/fgetwc.c (revision 6ae1554a5d9b318f8ad53ccc39fa5a961403da73)
1 /*-
2  * Copyright (c) 2002-2004 Tim J. Robbins.
3  * All rights reserved.
4  *
5  * Copyright (c) 2011 The FreeBSD Foundation
6  * All rights reserved.
7  * Portions of this software were developed by David Chisnall
8  * under sponsorship from the FreeBSD Foundation.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "namespace.h"
36 #include <errno.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <wchar.h>
40 #include "un-namespace.h"
41 #include "libc_private.h"
42 #include "local.h"
43 #include "mblocal.h"
44 #include "xlocale_private.h"
45 
46 /*
47  * MT-safe version.
48  */
49 wint_t
50 fgetwc_l(FILE *fp, locale_t locale)
51 {
52 	wint_t r;
53 	FIX_LOCALE(locale);
54 
55 	FLOCKFILE(fp);
56 	ORIENT(fp, 1);
57 	r = __fgetwc(fp, locale);
58 	FUNLOCKFILE(fp);
59 
60 	return (r);
61 }
62 
63 wint_t
64 fgetwc(FILE *fp)
65 {
66 	return fgetwc_l(fp, __get_locale());
67 }
68 
69 /*
70  * Internal (non-MPSAFE) version of fgetwc().  This version takes an
71  * mbstate_t argument specifying the initial conversion state.  For
72  * wide streams, this should always be fp->_mbstate.  On return, *nread
73  * is set to the number of bytes read.
74  */
75 wint_t
76 __fgetwc_mbs(FILE *fp, mbstate_t *mbs, int *nread, locale_t locale)
77 {
78 	wchar_t wc;
79 	size_t nconv;
80 	struct xlocale_ctype *l = XLOCALE_CTYPE(locale);
81 
82 	if (fp->_r <= 0 && __srefill(fp)) {
83 		*nread = 0;
84 		return (WEOF);
85 	}
86 	if (MB_CUR_MAX == 1) {
87 		/* Fast path for single-byte encodings. */
88 		wc = *fp->_p++;
89 		fp->_r--;
90 		*nread = 1;
91 		return (wc);
92 	}
93 	*nread = 0;
94 	do {
95 		nconv = l->__mbrtowc(&wc, fp->_p, fp->_r, mbs);
96 		if (nconv == (size_t)-1)
97 			break;
98 		else if (nconv == (size_t)-2)
99 			continue;
100 		else if (nconv == 0) {
101 			fp->_p++;
102 			fp->_r--;
103 			(*nread)++;
104 			return (L'\0');
105 		} else {
106 			fp->_p += nconv;
107 			fp->_r -= nconv;
108 			*nread += nconv;
109 			return (wc);
110 		}
111 	} while (__srefill(fp) == 0);
112 	fp->_flags |= __SERR;
113 	errno = EILSEQ;
114 	return (WEOF);
115 }
116