1 /****************************************************************************
2 * Copyright 2020 Thomas E. Dickey *
3 * Copyright 1998-2011,2012 Free Software Foundation, Inc. *
4 * *
5 * Permission is hereby granted, free of charge, to any person obtaining a *
6 * copy of this software and associated documentation files (the *
7 * "Software"), to deal in the Software without restriction, including *
8 * without limitation the rights to use, copy, modify, merge, publish, *
9 * distribute, distribute with modifications, sublicense, and/or sell *
10 * copies of the Software, and to permit persons to whom the Software is *
11 * furnished to do so, subject to the following conditions: *
12 * *
13 * The above copyright notice and this permission notice shall be included *
14 * in all copies or substantial portions of the Software. *
15 * *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
19 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
20 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
22 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
23 * *
24 * Except as contained in this notice, the name(s) of the above copyright *
25 * holders shall not be used in advertising or otherwise to promote the *
26 * sale, use or other dealings in this Software without prior written *
27 * authorization. *
28 ****************************************************************************/
29
30 /****************************************************************************
31 * Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995 *
32 * and: Eric S. Raymond <esr@snark.thyrsus.com> *
33 * and: Thomas E. Dickey 1996-on *
34 * and: Juergen Pfeifer 2009 *
35 ****************************************************************************/
36
37 /*
38 ** lib_ungetch.c
39 **
40 ** The routine ungetch().
41 **
42 */
43
44 #include <curses.priv.h>
45
46 MODULE_ID("$Id: lib_ungetch.c,v 1.17 2020/02/02 23:34:34 tom Exp $")
47
48 #include <fifo_defs.h>
49
50 #ifdef TRACE
NCURSES_EXPORT(void)51 NCURSES_EXPORT(void)
52 _nc_fifo_dump(SCREEN *sp)
53 {
54 int i;
55 T(("head = %d, tail = %d, peek = %d", head, tail, peek));
56 for (i = 0; i < 10; i++)
57 T(("char %d = %s", i, _nc_tracechar(sp, sp->_fifo[i])));
58 }
59 #endif /* TRACE */
60
61 NCURSES_EXPORT(int)
safe_ungetch(SCREEN * sp,int ch)62 safe_ungetch(SCREEN *sp, int ch)
63 {
64 int rc = ERR;
65
66 T((T_CALLED("ungetch(%p,%s)"), (void *) sp, _nc_tracechar(sp, ch)));
67
68 if (sp != 0 && tail >= 0) {
69 if (head < 0) {
70 head = 0;
71 t_inc();
72 peek = tail; /* no raw keys */
73 } else {
74 h_dec();
75 }
76
77 sp->_fifo[head] = ch;
78 T(("ungetch %s ok", _nc_tracechar(sp, ch)));
79 #ifdef TRACE
80 if (USE_TRACEF(TRACE_IEVENT)) {
81 _nc_fifo_dump(sp);
82 _nc_unlock_global(tracef);
83 }
84 #endif
85 rc = OK;
86 }
87 returnCode(rc);
88 }
89
90 NCURSES_EXPORT(int)
ungetch(int ch)91 ungetch(int ch)
92 {
93 return safe_ungetch(CURRENT_SCREEN, ch);
94 }
95