1/****************************************************************************
2 * Copyright (c) 1998-2007,2008 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 *     and: Thomas E. Dickey                        1996-on                 *
33 ****************************************************************************/
34
35/*
36**	lib_ungetch.c
37**
38**	The routine ungetch().
39**
40*/
41
42#include <curses.priv.h>
43
44MODULE_ID("$Id: lib_ungetch.c,v 1.11 2008/05/31 16:44:54 tom Exp $")
45
46#include <fifo_defs.h>
47
48#ifdef TRACE
49NCURSES_EXPORT(void)
50_nc_fifo_dump(SCREEN *sp)
51{
52    int i;
53    T(("head = %d, tail = %d, peek = %d", head, tail, peek));
54    for (i = 0; i < 10; i++)
55	T(("char %d = %s", i, _nc_tracechar(sp, sp->_fifo[i])));
56}
57#endif /* TRACE */
58
59NCURSES_EXPORT(int)
60_nc_ungetch(SCREEN *sp, int ch)
61{
62    int rc = ERR;
63
64    if (!sp) {
65	    returnCode(ERR);
66    }
67
68    if (tail != -1) {
69	if (head == -1) {
70	    head = 0;
71	    t_inc();
72	    peek = tail;	/* no raw keys */
73	} else
74	    h_dec();
75
76	sp->_fifo[head] = ch;
77	T(("ungetch %s ok", _nc_tracechar(sp, ch)));
78#ifdef TRACE
79	if (USE_TRACEF(TRACE_IEVENT)) {
80	    _nc_fifo_dump(sp);
81	    _nc_unlock_global(tracef);
82	}
83#endif
84	rc = OK;
85    }
86    return rc;
87}
88
89NCURSES_EXPORT(int)
90ungetch(int ch)
91{
92    T((T_CALLED("ungetch(%s)"), _nc_tracechar(SP, ch)));
93    returnCode(_nc_ungetch(SP, ch));
94}
95