ttyin.c revision 128345 
1/*
2 * Copyright (C) 1984-2002  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;
29
30/*
31 * Open keyboard for input.
32 */
33	public void
34open_getchr()
35{
36#if MSDOS_COMPILER==WIN32C
37	/* Need this to let child processes inherit our console handle */
38	SECURITY_ATTRIBUTES sa;
39	memset(&sa, 0, sizeof(SECURITY_ATTRIBUTES));
40	sa.nLength = sizeof(SECURITY_ATTRIBUTES);
41	sa.bInheritHandle = TRUE;
42	tty = (int) CreateFile("CONIN$", GENERIC_READ,
43			FILE_SHARE_READ, &sa,
44			OPEN_EXISTING, 0L, NULL);
45	GetConsoleMode((HANDLE)tty, &console_mode);
46	/* Make sure we get Ctrl+C events. */
47	SetConsoleMode((HANDLE)tty, ENABLE_PROCESSED_INPUT);
48#else
49#if MSDOS_COMPILER
50	extern int fd0;
51	/*
52	 * Open a new handle to CON: in binary mode
53	 * for unbuffered keyboard read.
54	 */
55	 fd0 = dup(0);
56	 close(0);
57	 tty = open("CON", OPEN_READ);
58#if MSDOS_COMPILER==DJGPPC
59	/*
60	 * Setting stdin to binary causes Ctrl-C to not
61	 * raise SIGINT.  We must undo that side-effect.
62	 */
63	(void) __djgpp_set_ctrl_c(1);
64#endif
65#else
66	/*
67	 * Try /dev/tty.
68	 * If that doesn't work, use file descriptor 2,
69	 * which in Unix is usually attached to the screen,
70	 * but also usually lets you read from the keyboard.
71	 */
72#if OS2
73	/* The __open() system call translates "/dev/tty" to "con". */
74	tty = __open("/dev/tty", OPEN_READ);
75#else
76	tty = open("/dev/tty", OPEN_READ);
77#endif
78	if (tty < 0)
79		tty = 2;
80#endif
81#endif
82}
83
84/*
85 * Close the keyboard.
86 */
87	public void
88close_getchr()
89{
90#if MSDOS_COMPILER==WIN32C
91	SetConsoleMode((HANDLE)tty, console_mode);
92	CloseHandle((HANDLE)tty);
93#endif
94}
95
96/*
97 * Get a character from the keyboard.
98 */
99	public int
100getchr()
101{
102	char c;
103	int result;
104
105	do
106	{
107#if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
108		/*
109		 * In raw read, we don't see ^C so look here for it.
110		 */
111		flush();
112#if MSDOS_COMPILER==WIN32C
113		if (ABORT_SIGS())
114			return (READ_INTR);
115		c = WIN32getch(tty);
116#else
117		c = getch();
118#endif
119		result = 1;
120		if (c == '\003')
121			return (READ_INTR);
122#else
123		result = iread(tty, &c, sizeof(char));
124		if (result == READ_INTR)
125			return (READ_INTR);
126		if (result < 0)
127		{
128			/*
129			 * Don't call error() here,
130			 * because error calls getchr!
131			 */
132			quit(QUIT_ERROR);
133		}
134#endif
135		/*
136		 * Various parts of the program cannot handle
137		 * an input character of '\0'.
138		 * If a '\0' was actually typed, convert it to '\340' here.
139		 */
140		if (c == '\0')
141			c = '\340';
142	} while (result != 1);
143
144	return (c & 0377);
145}
146