xref: /freebsd/lib/libc/stdio/fgetwc.c (revision 1e98f88776fc606df245a382685b1ac634a81389)
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 #include "mblocal.h"
39 
40 /*
41  * MT-safe version.
42  */
43 wint_t
44 fgetwc(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  */
59 wint_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->_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