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            *
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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  *                                                                          *
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14  *                                                                          *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
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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   *
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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 
44 MODULE_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
49 NCURSES_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 
59 NCURSES_EXPORT(int)
60 _nc_ungetch(SCREEN *sp, int ch)
61 {
62     int rc = ERR;
63 
64     if (tail != -1) {
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", _nc_tracechar(sp, ch)));
74 #ifdef TRACE
75 	if (USE_TRACEF(TRACE_IEVENT)) {
76 	    _nc_fifo_dump(sp);
77 	    _nc_unlock_global(tracef);
78 	}
79 #endif
80 	rc = OK;
81     }
82     return rc;
83 }
84 
85 NCURSES_EXPORT(int)
86 ungetch(int ch)
87 {
88     T((T_CALLED("ungetch(%s)"), _nc_tracechar(SP, ch)));
89     returnCode(_nc_ungetch(SP, ch));
90 }
91