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      1 /*
      2  * Copyright (C) 2006 Michael Brown <mbrown (at) 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