xref: /freebsd/lib/libc/stdio/ungetwc.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
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 <limits.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <wchar.h>
36 #include "un-namespace.h"
37 #include "libc_private.h"
38 #include "local.h"
39 #include "mblocal.h"
40 
41 /*
42  * Non-MT-safe version.
43  */
44 wint_t
45 __ungetwc(wint_t wc, FILE *fp)
46 {
47 	char buf[MB_LEN_MAX];
48 	size_t len;
49 
50 	if (wc == WEOF)
51 		return (WEOF);
52 	if ((len = __wcrtomb(buf, wc, &fp->_extra->mbstate)) == (size_t)-1) {
53 		fp->_flags |= __SERR;
54 		return (WEOF);
55 	}
56 	while (len-- != 0)
57 		if (__ungetc((unsigned char)buf[len], fp) == EOF)
58 			return (WEOF);
59 
60 	return (wc);
61 }
62 
63 /*
64  * MT-safe version.
65  */
66 wint_t
67 ungetwc(wint_t wc, FILE *fp)
68 {
69 	wint_t r;
70 
71 	FLOCKFILE(fp);
72 	ORIENT(fp, 1);
73 	r = __ungetwc(wc, fp);
74 	FUNLOCKFILE(fp);
75 
76 	return (r);
77 }
78