1/*	$OpenBSD: ungetwc.c,v 1.6 2015/08/31 02:53:57 guenther Exp $	*/
2/* $NetBSD: ungetwc.c,v 1.2 2003/01/18 11:29:59 thorpej Exp $ */
3
4/*-
5 * Copyright (c)2001 Citrus Project,
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $Citrus$
30 */
31
32#include <errno.h>
33#include <stdio.h>
34#include <wchar.h>
35#include "local.h"
36
37wint_t
38__ungetwc(wint_t wc, FILE *fp)
39{
40	struct wchar_io_data *wcio;
41
42	if (wc == WEOF)
43		return WEOF;
44
45	_SET_ORIENTATION(fp, 1);
46	/*
47	 * XXX since we have no way to transform a wchar string to
48	 * a char string in reverse order, we can't use ungetc.
49	 */
50	/* XXX should we flush ungetc buffer? */
51
52	wcio = WCIO_GET(fp);
53	if (wcio == 0) {
54		errno = ENOMEM; /* XXX */
55		return WEOF;
56	}
57
58	if (wcio->wcio_ungetwc_inbuf >= WCIO_UNGETWC_BUFSIZE) {
59		return WEOF;
60	}
61
62	wcio->wcio_ungetwc_buf[wcio->wcio_ungetwc_inbuf++] = wc;
63	__sclearerr(fp);
64
65	return wc;
66}
67
68wint_t
69ungetwc(wint_t wc, FILE *fp)
70{
71	wint_t r;
72
73	FLOCKFILE(fp);
74	r = __ungetwc(wc, fp);
75	FUNLOCKFILE(fp);
76	return (r);
77}
78DEF_STRONG(ungetwc);
79