iPXE
getkey.c
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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., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA.
18  *
19  * You can also choose to distribute this program under the terms of
20  * the Unmodified Binary Distribution Licence (as given in the file
21  * COPYING.UBDL), provided that you have satisfied its requirements.
22  */
23 
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25 
26 #include <ctype.h>
27 #include <ipxe/console.h>
28 #include <ipxe/process.h>
29 #include <ipxe/keys.h>
30 #include <ipxe/timer.h>
31 #include <ipxe/nap.h>
32 
33 /** @file
34  *
35  * Special key interpretation
36  *
37  */
38 
39 #define GETKEY_TIMEOUT ( TICKS_PER_SEC / 4 )
40 
41 /**
42  * Read character from console if available within timeout period
43  *
44  * @v timeout Timeout period, in ticks (0=indefinite)
45  * @ret character Character read from console
46  */
47 static int getchar_timeout ( unsigned long timeout ) {
48  unsigned long start = currticks();
49 
50  while ( ( timeout == 0 ) || ( ( currticks() - start ) < timeout ) ) {
51  step();
52  if ( iskey() )
53  return getchar();
54  cpu_nap();
55  }
56 
57  return -1;
58 }
59 
60 /**
61  * Get single keypress
62  *
63  * @v timeout Timeout period, in ticks (0=indefinite)
64  * @ret key Key pressed
65  *
66  * The returned key will be an ASCII value or a KEY_XXX special
67  * constant. This function differs from getchar() in that getchar()
68  * will return "special" keys (e.g. cursor keys) as a series of
69  * characters forming an ANSI escape sequence.
70  */
71 int getkey ( unsigned long timeout ) {
72  int character;
73  unsigned int n = 0;
74 
75  character = getchar_timeout ( timeout );
76  if ( character != ESC )
77  return character;
78 
79  character = getchar_timeout ( GETKEY_TIMEOUT );
80  if ( character < 0 )
81  return ESC;
82 
83  if ( isalpha ( character ) )
84  return ( toupper ( character ) - 'A' + 1 );
85 
86  while ( ( character = getchar_timeout ( GETKEY_TIMEOUT ) ) >= 0 ) {
87  if ( isdigit ( character ) ) {
88  n = ( ( n * 10 ) + ( character - '0' ) );
89  continue;
90  }
91  if ( character >= 0x40 )
92  return KEY_ANSI ( n, character );
93  }
94 
95  return ESC;
96 }
int getkey(unsigned long timeout)
Get single keypress.
Definition: getkey.c:71
CPU sleeping.
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
iPXE timers
static int isalpha(int character)
Check if character is alphabetic.
Definition: ctype.h:64
Character types.
uint32_t start
Starting offset.
Definition: netvsc.h:12
static int toupper(int character)
Convert character to upper case.
Definition: ctype.h:109
static int isdigit(int character)
Check if character is a decimal digit.
Definition: ctype.h:18
#define ESC
Escape character.
Definition: ansiesc.h:92
User interaction.
int getchar(void)
Read a single character from any console.
Definition: console.c:82
Processes.
void cpu_nap(void)
Sleep until next CPU interrupt.
Key definitions.
void step(void)
Single-step a single process.
Definition: process.c:98
static int getchar_timeout(unsigned long timeout)
Read character from console if available within timeout period.
Definition: getkey.c:47
void timeout(int)
unsigned int n
Definition: entropy.h:159
unsigned long currticks(void)
Get current system time in ticks.
Definition: timer.c:42
#define GETKEY_TIMEOUT
Definition: getkey.c:39
#define KEY_ANSI(n, terminator)
Definition: keys.h:60
int iskey(void)
Check for available input on any console.
Definition: console.c:127