ttyin.c revision 161475 
1/*
2 * Copyright (C) 1984-2004  Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information about less, or for information on how to
8 * contact the author, see the README file.
9 */
10
11
12/*
13 * Routines dealing with getting input from the keyboard (i.e. from the user).
14 */
15
16#include "less.h"
17#if OS2
18#include "cmd.h"
19#include "pckeys.h"
20#endif
21#if MSDOS_COMPILER==WIN32C
22#include "windows.h"
23extern char WIN32getch();
24static DWORD console_mode;
25#endif
26
27public int tty;
28extern int sigs;
29extern int utf_mode;
30
31/*
32 * Open keyboard for input.
33 */
34	public void
35open_getchr()
36{
37#if MSDOS_COMPILER==WIN32C
38	/* Need this to let child processes inherit our console handle */
39	SECURITY_ATTRIBUTES sa;
40	memset(&sa, 0, sizeof(SECURITY_ATTRIBUTES));
41	sa.nLength = sizeof(SECURITY_ATTRIBUTES);
42	sa.bInheritHandle = TRUE;
43	tty = (int) CreateFile("CONIN$", GENERIC_READ,
44			FILE_SHARE_READ, &sa,
45			OPEN_EXISTING, 0L, NULL);
46	GetConsoleMode((HANDLE)tty, &console_mode);
47	/* Make sure we get Ctrl+C events. */
48	SetConsoleMode((HANDLE)tty, ENABLE_PROCESSED_INPUT);
49#else
50#if MSDOS_COMPILER
51	extern int fd0;
52	/*
53	 * Open a new handle to CON: in binary mode
54	 * for unbuffered keyboard read.
55	 */
56	 fd0 = dup(0);
57	 close(0);
58	 tty = open("CON", OPEN_READ);
59#if MSDOS_COMPILER==DJGPPC
60	/*
61	 * Setting stdin to binary causes Ctrl-C to not
62	 * raise SIGINT.  We must undo that side-effect.
63	 */
64	(void) __djgpp_set_ctrl_c(1);
65#endif
66#else
67	/*
68	 * Try /dev/tty.
69	 * If that doesn't work, use file descriptor 2,
70	 * which in Unix is usually attached to the screen,
71	 * but also usually lets you read from the keyboard.
72	 */
73#if OS2
74	/* The __open() system call translates "/dev/tty" to "con". */
75	tty = __open("/dev/tty", OPEN_READ);
76#else
77	tty = open("/dev/tty", OPEN_READ);
78#endif
79	if (tty < 0)
80		tty = 2;
81#endif
82#endif
83}
84
85/*
86 * Close the keyboard.
87 */
88	public void
89close_getchr()
90{
91#if MSDOS_COMPILER==WIN32C
92	SetConsoleMode((HANDLE)tty, console_mode);
93	CloseHandle((HANDLE)tty);
94#endif
95}
96
97/*
98 * Get a character from the keyboard.
99 */
100	public int
101getchr()
102{
103	char c;
104	int result;
105	int hex_in = 0;
106	int hex_value = 0;
107
108	do
109	{
110#if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
111		/*
112		 * In raw read, we don't see ^C so look here for it.
113		 */
114		flush();
115#if MSDOS_COMPILER==WIN32C
116		if (ABORT_SIGS())
117			return (READ_INTR);
118		c = WIN32getch(tty);
119#else
120		c = getch();
121#endif
122		result = 1;
123		if (c == '\003')
124			return (READ_INTR);
125#else
126		result = iread(tty, &c, sizeof(char));
127		if (result == READ_INTR)
128			return (READ_INTR);
129		if (result < 0)
130		{
131			/*
132			 * Don't call error() here,
133			 * because error calls getchr!
134			 */
135			quit(QUIT_ERROR);
136		}
137#endif
138#if 0 /* allow entering arbitrary hex chars for testing */
139		/* ctrl-A followed by two hex chars makes a byte */
140		if (c == CONTROL('A'))
141		{
142			hex_in = 2;
143			result = 0;
144			continue;
145		}
146		if (hex_in > 0)
147		{
148			int v;
149			if (c >= '0' && c <= '9')
150				v = c - '0';
151			else if (c >= 'a' && c <= 'f')
152				v = c - 'a' + 10;
153			else if (c >= 'A' && c <= 'F')
154				v = c - 'A' + 10;
155			else
156				hex_in = 0;
157			hex_value = (hex_value << 4) | v;
158			if (--hex_in > 0)
159			{
160				result = 0;
161				continue;
162			}
163			c = hex_value;
164		}
165#endif
166		/*
167		 * Various parts of the program cannot handle
168		 * an input character of '\0'.
169		 * If a '\0' was actually typed, convert it to '\340' here.
170		 */
171		if (c == '\0')
172			c = '\340';
173	} while (result != 1);
174
175	return (c & 0xFF);
176}
177