src/core/getkey.c

   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 #include <ctype.h>
  20 #include <console.h>
  21 #include <gpxe/process.h>
  22 #include <gpxe/keys.h>
  23 #include <gpxe/timer.h>
  24
  25 /** @file
  26  *
  27  * Special key interpretation
  28  *
  29  */
  30
  31 #define GETKEY_TIMEOUT ( TICKS_PER_SEC / 4 )
  32
  33 /**
  34  * Read character from console if available within timeout period
  35  *
  36  * @v timeout           Timeout period, in ticks
  37  * @ret character       Character read from console
  38  */
  39 static int getchar_timeout ( unsigned long timeout ) {
  40         unsigned long expiry = ( currticks() + timeout );
  41
  42         while ( currticks() < expiry ) {
  43                 step();
  44                 if ( iskey() )
  45                         return getchar();
  46         }
  47
  48         return -1;
  49 }
  50
  51 /**
  52  * Get single keypress
  53  *
  54  * @ret key             Key pressed
  55  *
  56  * The returned key will be an ASCII value or a KEY_XXX special
  57  * constant.  This function differs from getchar() in that getchar()
  58  * will return "special" keys (e.g. cursor keys) as a series of
  59  * characters forming an ANSI escape sequence.
  60  */
  61 int getkey ( void ) {
  62         int character;
  63         unsigned int n = 0;
  64
  65         character = getchar();
  66         if ( character != ESC )
  67                 return character;
  68
  69         while ( ( character = getchar_timeout ( GETKEY_TIMEOUT ) ) >= 0 ) {
  70                 if ( character == '[' )
  71                         continue;
  72                 if ( isdigit ( character ) ) {
  73                         n = ( ( n * 10 ) + ( character - '0' ) );
  74                         continue;
  75                 }
  76                 if ( character >= 0x40 )
  77                         return KEY_ANSI ( n, character );
  78         }
  79
  80         return ESC;
  81 }