1 /* $NetBSD: ungetwc.c,v 1.3 2005/06/12 05:21:27 lukem Exp $ */
2
3 /*-
4 * Copyright (c)2001 Citrus Project,
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $Citrus$
29 */
30
31 #include <sys/cdefs.h>
32 #if defined(LIBC_SCCS) && !defined(lint)
33 __RCSID("$NetBSD: ungetwc.c,v 1.3 2005/06/12 05:21:27 lukem Exp $");
34 #endif /* LIBC_SCCS and not lint */
35
36 #include <assert.h>
37 #include <errno.h>
38 #include <stdio.h>
39 #include <wchar.h>
40 #include "reentrant.h"
41 #include "local.h"
42
43 wint_t
ungetwc(wint_t wc,FILE * fp)44 ungetwc(wint_t wc, FILE *fp)
45 {
46 struct wchar_io_data *wcio;
47
48 _DIAGASSERT(fp);
49
50 if (wc == WEOF)
51 return WEOF;
52
53 FLOCKFILE(fp);
54 _SET_ORIENTATION(fp, 1);
55 /*
56 * XXX since we have no way to transform a wchar string to
57 * a char string in reverse order, we can't use ungetc.
58 */
59 /* XXX should we flush ungetc buffer? */
60
61 wcio = WCIO_GET(fp);
62 if (wcio == 0) {
63 FUNLOCKFILE(fp);
64 errno = ENOMEM; /* XXX */
65 return WEOF;
66 }
67
68 if (wcio->wcio_ungetwc_inbuf >= WCIO_UNGETWC_BUFSIZE) {
69 FUNLOCKFILE(fp);
70 return WEOF;
71 }
72
73 wcio->wcio_ungetwc_buf[wcio->wcio_ungetwc_inbuf++] = wc;
74 __sclearerr(fp);
75 FUNLOCKFILE(fp);
76
77 return wc;
78 }
79