1/* $OpenBSD: lib_ungetch.c,v 1.4 2023/10/17 09:52:09 nicm Exp $ */
2
3/****************************************************************************
4 * Copyright 2020 Thomas E. Dickey                                          *
5 * Copyright 1998-2011,2012 Free Software Foundation, Inc.                  *
6 *                                                                          *
7 * Permission is hereby granted, free of charge, to any person obtaining a  *
8 * copy of this software and associated documentation files (the            *
9 * "Software"), to deal in the Software without restriction, including      *
10 * without limitation the rights to use, copy, modify, merge, publish,      *
11 * distribute, distribute with modifications, sublicense, and/or sell       *
12 * copies of the Software, and to permit persons to whom the Software is    *
13 * furnished to do so, subject to the following conditions:                 *
14 *                                                                          *
15 * The above copyright notice and this permission notice shall be included  *
16 * in all copies or substantial portions of the Software.                   *
17 *                                                                          *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
21 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
24 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
25 *                                                                          *
26 * Except as contained in this notice, the name(s) of the above copyright   *
27 * holders shall not be used in advertising or otherwise to promote the     *
28 * sale, use or other dealings in this Software without prior written       *
29 * authorization.                                                           *
30 ****************************************************************************/
31
32/****************************************************************************
33 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
34 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
35 *     and: Thomas E. Dickey                        1996-on                 *
36 *     and: Juergen Pfeifer                         2009                    *
37 ****************************************************************************/
38
39/*
40**	lib_ungetch.c
41**
42**	The routine ungetch().
43**
44*/
45
46#include <curses.priv.h>
47
48MODULE_ID("$Id: lib_ungetch.c,v 1.4 2023/10/17 09:52:09 nicm Exp $")
49
50#include <fifo_defs.h>
51
52#ifdef TRACE
53NCURSES_EXPORT(void)
54_nc_fifo_dump(SCREEN *sp)
55{
56    int i;
57    T(("head = %d, tail = %d, peek = %d", head, tail, peek));
58    for (i = 0; i < 10; i++)
59	T(("char %d = %s", i, _nc_tracechar(sp, sp->_fifo[i])));
60}
61#endif /* TRACE */
62
63NCURSES_EXPORT(int)
64safe_ungetch(SCREEN *sp, int ch)
65{
66    int rc = ERR;
67
68    T((T_CALLED("ungetch(%p,%s)"), (void *) sp, _nc_tracechar(sp, ch)));
69
70    if (sp != 0 && tail >= 0) {
71	if (head < 0) {
72	    head = 0;
73	    t_inc();
74	    peek = tail;	/* no raw keys */
75	} else {
76	    h_dec();
77	}
78
79	sp->_fifo[head] = ch;
80	T(("ungetch %s ok", _nc_tracechar(sp, ch)));
81#ifdef TRACE
82	if (USE_TRACEF(TRACE_IEVENT)) {
83	    _nc_fifo_dump(sp);
84	    _nc_unlock_global(tracef);
85	}
86#endif
87	rc = OK;
88    }
89    returnCode(rc);
90}
91
92NCURSES_EXPORT(int)
93ungetch(int ch)
94{
95    return safe_ungetch(CURRENT_SCREEN, ch);
96}
97