1/* $NetBSD: ungetwc.c,v 1.2 2003/01/18 11:29:59 thorpej 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("$NetBSD$");
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
43wint_t
44ungetwc(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