1 /*
2  * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation; either version 2 of the
7  * License, or any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17  */
18 
19 FILE_LICENCE ( GPL2_OR_LATER );
20 
21 #include <ctype.h>
22 #include <console.h>
23 #include <gpxe/process.h>
24 #include <gpxe/keys.h>
25 #include <gpxe/timer.h>
26 
27 /** @file
28  *
29  * Special key interpretation
30  *
31  */
32 
33 #define GETKEY_TIMEOUT ( TICKS_PER_SEC / 4 )
34 
35 /**
36  * Read character from console if available within timeout period
37  *
38  * @v timeout		Timeout period, in ticks
39  * @ret character	Character read from console
40  */
41 static int getchar_timeout ( unsigned long timeout ) {
42 	unsigned long expiry = ( currticks() + timeout );
43 
44 	while ( currticks() < expiry ) {
45 		step();
46 		if ( iskey() )
47 			return getchar();
48 	}
49 
50 	return -1;
51 }
52 
53 /**
54  * Get single keypress
55  *
56  * @ret key		Key pressed
57  *
58  * The returned key will be an ASCII value or a KEY_XXX special
59  * constant.  This function differs from getchar() in that getchar()
60  * will return "special" keys (e.g. cursor keys) as a series of
61  * characters forming an ANSI escape sequence.
62  */
63 int getkey ( void ) {
64 	int character;
65 	unsigned int n = 0;
66 
67 	character = getchar();
68 	if ( character != ESC )
69 		return character;
70 
71 	while ( ( character = getchar_timeout ( GETKEY_TIMEOUT ) ) >= 0 ) {
72 		if ( character == '[' )
73 			continue;
74 		if ( isdigit ( character ) ) {
75 			n = ( ( n * 10 ) + ( character - '0' ) );
76 			continue;
77 		}
78 		if ( character >= 0x40 )
79 			return KEY_ANSI ( n, character );
80 	}
81 
82 	return ESC;
83 }
84