Import the [now] dual licensed version 3.5.4 of less. It is

distributed under your choice of the GPL or a BSD style license.

Reviewed by:	peter
Obtained from:	http://home.flash.net/~marknu/less/

1 files changed, 270 insertions, 0 deletions

diff --git a/contrib/less/signal.c b/contrib/less/signal.c
new file mode 100644
index 0000000..f044980
--- /dev/null
+++ b/contrib/less/signal.c
@@ -0,0 +1,270 @@
+/*
+ * Copyright (C) 1984-2000  Mark Nudelman
+ *
+ * You may distribute under the terms of either the GNU General Public
+ * License or the Less License, as specified in the README file.
+ *
+ * For more information about less, or for information on how to 
+ * contact the author, see the README file.
+ */
+
+
+/*
+ * Routines dealing with signals.
+ *
+ * A signal usually merely causes a bit to be set in the "signals" word.
+ * At some convenient time, the mainline code checks to see if any
+ * signals need processing by calling psignal().
+ * If we happen to be reading from a file [in iread()] at the time
+ * the signal is received, we call intread to interrupt the iread.
+ */
+
+#include "less.h"
+#include <signal.h>
+
+/*
+ * "sigs" contains bits indicating signals which need to be processed.
+ */
+public int sigs;
+
+extern int sc_width, sc_height;
+extern int screen_trashed;
+extern int lnloop;
+extern int linenums;
+extern int wscroll;
+extern int reading;
+
+/*
+ * Interrupt signal handler.
+ */
+	/* ARGSUSED*/
+	static RETSIGTYPE
+u_interrupt(type)
+	int type;
+{
+#if OS2
+	LSIGNAL(SIGINT, SIG_ACK);
+#endif
+	LSIGNAL(SIGINT, u_interrupt);
+	sigs |= S_INTERRUPT;
+#if MSDOS_COMPILER==DJGPPC
+	/*
+	 * If a keyboard has been hit, it must be Ctrl-C
+	 * (as opposed to Ctrl-Break), so consume it.
+	 * (Otherwise, Less will beep when it sees Ctrl-C from keyboard.)
+	 */
+	if (kbhit())
+		getkey();
+#endif
+	if (reading)
+		intread();
+}
+
+#ifdef SIGTSTP
+/*
+ * "Stop" (^Z) signal handler.
+ */
+	/* ARGSUSED*/
+	static RETSIGTYPE
+stop(type)
+	int type;
+{
+	LSIGNAL(SIGTSTP, stop);
+	sigs |= S_STOP;
+	if (reading)
+		intread();
+}
+#endif
+
+#ifdef SIGWINCH
+/*
+ * "Window" change handler
+ */
+	/* ARGSUSED*/
+	public RETSIGTYPE
+winch(type)
+	int type;
+{
+	LSIGNAL(SIGWINCH, winch);
+	sigs |= S_WINCH;
+	if (reading)
+		intread();
+}
+#else
+#ifdef SIGWIND
+/*
+ * "Window" change handler
+ */
+	/* ARGSUSED*/
+	public RETSIGTYPE
+winch(type)
+	int type;
+{
+	LSIGNAL(SIGWIND, winch);
+	sigs |= S_WINCH;
+	if (reading)
+		intread();
+}
+#endif
+#endif
+
+#if MSDOS_COMPILER==WIN32C
+/*
+ * Handle CTRL-C and CTRL-BREAK keys.
+ */
+#include "windows.h"
+
+	static BOOL WINAPI 
+wbreak_handler(dwCtrlType)
+	DWORD dwCtrlType;
+{
+	switch (dwCtrlType)
+	{
+	case CTRL_C_EVENT:
+	case CTRL_BREAK_EVENT:
+		sigs |= S_INTERRUPT;
+		return (TRUE);
+	default:
+		break;
+	}
+	return (FALSE);
+}
+#endif
+
+/*
+ * Set up the signal handlers.
+ */
+	public void
+init_signals(on)
+	int on;
+{
+	if (on)
+	{
+		/*
+		 * Set signal handlers.
+		 */
+		(void) LSIGNAL(SIGINT, u_interrupt);
+#if MSDOS_COMPILER==WIN32C
+		SetConsoleCtrlHandler(wbreak_handler, TRUE);
+#endif
+#ifdef SIGTSTP
+		(void) LSIGNAL(SIGTSTP, stop);
+#endif
+#ifdef SIGWINCH
+		(void) LSIGNAL(SIGWINCH, winch);
+#else
+#ifdef SIGWIND
+		(void) LSIGNAL(SIGWIND, winch);
+#endif
+#ifdef SIGQUIT
+		(void) LSIGNAL(SIGQUIT, SIG_IGN);
+#endif
+#endif
+	} else
+	{
+		/*
+		 * Restore signals to defaults.
+		 */
+		(void) LSIGNAL(SIGINT, SIG_DFL);
+#if MSDOS_COMPILER==WIN32C
+		SetConsoleCtrlHandler(wbreak_handler, FALSE);
+#endif
+#ifdef SIGTSTP
+		(void) LSIGNAL(SIGTSTP, SIG_DFL);
+#endif
+#ifdef SIGWINCH
+		(void) LSIGNAL(SIGWINCH, SIG_IGN);
+#endif
+#ifdef SIGWIND
+		(void) LSIGNAL(SIGWIND, SIG_IGN);
+#endif
+#ifdef SIGQUIT
+		(void) LSIGNAL(SIGQUIT, SIG_DFL);
+#endif
+	}
+}
+
+/*
+ * Process any signals we have received.
+ * A received signal cause a bit to be set in "sigs".
+ */
+	public void
+psignals()
+{
+	register int tsignals;
+
+	if ((tsignals = sigs) == 0)
+		return;
+	sigs = 0;
+
+#ifdef SIGTSTP
+	if (tsignals & S_STOP)
+	{
+		/*
+		 * Clean up the terminal.
+		 */
+#ifdef SIGTTOU
+		LSIGNAL(SIGTTOU, SIG_IGN);
+#endif
+		clear_bot();
+		deinit();
+		flush();
+		raw_mode(0);
+#ifdef SIGTTOU
+		LSIGNAL(SIGTTOU, SIG_DFL);
+#endif
+		LSIGNAL(SIGTSTP, SIG_DFL);
+		kill(getpid(), SIGTSTP);
+		/*
+		 * ... Bye bye. ...
+		 * Hopefully we'll be back later and resume here...
+		 * Reset the terminal and arrange to repaint the
+		 * screen when we get back to the main command loop.
+		 */
+		LSIGNAL(SIGTSTP, stop);
+		raw_mode(1);
+		init();
+		screen_trashed = 1;
+		tsignals |= S_WINCH;
+	}
+#endif
+#ifdef S_WINCH
+	if (tsignals & S_WINCH)
+	{
+		int old_width, old_height;
+		/*
+		 * Re-execute scrsize() to read the new window size.
+		 */
+		old_width = sc_width;
+		old_height = sc_height;
+		get_term();
+		if (sc_width != old_width || sc_height != old_height)
+		{
+			wscroll = (sc_height + 1) / 2;
+			screen_trashed = 1;
+		}
+	}
+#endif
+	if (tsignals & S_INTERRUPT)
+	{
+		bell();
+		/*
+		 * {{ You may wish to replace the bell() with 
+		 *    error("Interrupt", NULL_PARG); }}
+		 */
+
+		/*
+		 * If we were interrupted while in the "calculating 
+		 * line numbers" loop, turn off line numbers.
+		 */
+		if (lnloop)
+		{
+			lnloop = 0;
+			if (linenums == 2)
+				screen_trashed = 1;
+			linenums = 0;
+			error("Line numbers turned off", NULL_PARG);
+		}
+
+	}
+}