xref: /titanic_41/usr/src/lib/libcurses/screen/ungetch.c (revision fcf3ce441efd61da9bb2884968af01cb7c1452cc)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 1997 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved	*/
29 
30 /*
31  * University Copyright- Copyright (c) 1982, 1986, 1988
32  * The Regents of the University of California
33  * All Rights Reserved
34  *
35  * University Acknowledgment- Portions of this document are derived from
36  * software developed by the University of California, Berkeley, and its
37  * contributors.
38  */
39 
40 #pragma ident	"%Z%%M%	%I%	%E% SMI"
41 
42 /*LINTLIBRARY*/
43 
44 #include <sys/types.h>
45 #include "curses_inc.h"
46 
47 /* Place a char onto the beginning of the input queue. */
48 
49 int
50 ungetch(int ch)
51 {
52 	int	i = cur_term->_chars_on_queue, j = i - 1;
53 	chtype	*inputQ = cur_term->_input_queue;
54 
55 	/* Place the character at the beg of the Q */
56 	/*
57 	 * Here is commented out because 'ch' should deal with a single byte
58 	 * character only. So ISCBIT(ch) is 0 every time.
59 	 *
60 	 * register chtype	r;
61 	 *
62 	 * if (ISCBIT(ch)) {
63 	 *	r = RBYTE(ch);
64 	 *	ch = LBYTE(ch);
65 	 *	-* do the right half first to maintain the byte order *-
66 	 *	if (r != MBIT && ungetch(r) == ERR)
67 	 *		return (ERR);
68 	 * }
69 	 */
70 
71 	while (i > 0)
72 		inputQ[i--] = inputQ[j--];
73 	cur_term->_ungotten++;
74 	inputQ[0] = -ch;
75 	cur_term->_chars_on_queue++;
76 	return (0);
77 }
78