1/****************************************************************************
2 * Copyright (c) 1998-2001,2002 Free Software Foundation, Inc.              *
3 *                                                                          *
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5 * copy of this software and associated documentation files (the            *
6 * "Software"), to deal in the Software without restriction, including      *
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8 * distribute, distribute with modifications, sublicense, and/or sell       *
9 * copies of the Software, and to permit persons to whom the Software is    *
10 * furnished to do so, subject to the following conditions:                 *
11 *                                                                          *
12 * The above copyright notice and this permission notice shall be included  *
13 * in all copies or substantial portions of the Software.                   *
14 *                                                                          *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
16 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
18 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
19 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
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21 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
22 *                                                                          *
23 * Except as contained in this notice, the name(s) of the above copyright   *
24 * holders shall not be used in advertising or otherwise to promote the     *
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27 ****************************************************************************/
28
29/****************************************************************************
30 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
31 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
32 ****************************************************************************/
33
34/*
35**	lib_ungetch.c
36**
37**	The routine ungetch().
38**
39*/
40
41#include <curses.priv.h>
42
43MODULE_ID("$Id: lib_ungetch.c,v 1.8 2002/08/24 22:08:48 tom Exp $")
44
45#include <fifo_defs.h>
46
47#ifdef TRACE
48NCURSES_EXPORT(void)
49_nc_fifo_dump(void)
50{
51    int i;
52    T(("head = %d, tail = %d, peek = %d", head, tail, peek));
53    for (i = 0; i < 10; i++)
54	T(("char %d = %s", i, _tracechar(SP->_fifo[i])));
55}
56#endif /* TRACE */
57
58NCURSES_EXPORT(int)
59ungetch(int ch)
60{
61    T((T_CALLED("ungetch(%s)"), _tracechar(ch)));
62
63    if (tail == -1)
64	returnCode(ERR);
65    if (head == -1) {
66	head = 0;
67	t_inc()
68	    peek = tail;	/* no raw keys */
69    } else
70	h_dec();
71
72    SP->_fifo[head] = ch;
73    T(("ungetch %s ok", _tracechar(ch)));
74#ifdef TRACE
75    if (_nc_tracing & TRACE_IEVENT)
76	_nc_fifo_dump();
77#endif
78    returnCode(OK);
79}
80