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, 287 insertions, 0 deletions

diff --git a/contrib/less/jump.c b/contrib/less/jump.c
new file mode 100644
index 0000000..a8f9c6a
--- /dev/null
+++ b/contrib/less/jump.c
@@ -0,0 +1,287 @@
+/*
+ * 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 which jump to a new location in the file.
+ */
+
+#include "less.h"
+#include "position.h"
+
+extern int hit_eof;
+extern int jump_sline;
+extern int squished;
+extern int screen_trashed;
+extern int sc_width, sc_height;
+extern int show_attn;
+
+/*
+ * Jump to the end of the file.
+ */
+	public void
+jump_forw()
+{
+	POSITION pos;
+
+	if (ch_end_seek())
+	{
+		error("Cannot seek to end of file", NULL_PARG);
+		return;
+	}
+	/*
+	 * Position the last line in the file at the last screen line.
+	 * Go back one line from the end of the file
+	 * to get to the beginning of the last line.
+	 */
+	pos = back_line(ch_tell());
+	if (pos == NULL_POSITION)
+		jump_loc((POSITION)0, sc_height-1);
+	else
+		jump_loc(pos, sc_height-1);
+}
+
+/*
+ * Jump to line n in the file.
+ */
+	public void
+jump_back(n)
+	int n;
+{
+	POSITION pos;
+	PARG parg;
+
+	/*
+	 * Find the position of the specified line.
+	 * If we can seek there, just jump to it.
+	 * If we can't seek, but we're trying to go to line number 1,
+	 * use ch_beg_seek() to get as close as we can.
+	 */
+	pos = find_pos(n);
+	if (pos != NULL_POSITION && ch_seek(pos) == 0)
+	{
+		if (show_attn)
+			set_attnpos(pos);
+		jump_loc(pos, jump_sline);
+	} else if (n <= 1 && ch_beg_seek() == 0)
+	{
+		jump_loc(ch_tell(), jump_sline);
+		error("Cannot seek to beginning of file", NULL_PARG);
+	} else
+	{
+		parg.p_int = n;
+		error("Cannot seek to line number %d", &parg);
+	}
+}
+
+/*
+ * Repaint the screen.
+ */
+	public void
+repaint()
+{
+	struct scrpos scrpos;
+	/*
+	 * Start at the line currently at the top of the screen
+	 * and redisplay the screen.
+	 */
+	get_scrpos(&scrpos);
+	pos_clear();
+	jump_loc(scrpos.pos, scrpos.ln);
+}
+
+/*
+ * Jump to a specified percentage into the file.
+ */
+	public void
+jump_percent(percent)
+	int percent;
+{
+	POSITION pos, len;
+
+	/*
+	 * Determine the position in the file
+	 * (the specified percentage of the file's length).
+	 */
+	if ((len = ch_length()) == NULL_POSITION)
+	{
+		ierror("Determining length of file", NULL_PARG);
+		ch_end_seek();
+	}
+	if ((len = ch_length()) == NULL_POSITION)
+	{
+		error("Don't know length of file", NULL_PARG);
+		return;
+	}
+	pos = percent_pos(len, percent);
+	if (pos >= len)
+		pos = len-1;
+
+	jump_line_loc(pos, jump_sline);
+}
+
+/*
+ * Jump to a specified position in the file.
+ * Like jump_loc, but the position need not be 
+ * the first character in a line.
+ */
+	public void
+jump_line_loc(pos, sline)
+	POSITION pos;
+	int sline;
+{
+	int c;
+
+	if (ch_seek(pos) == 0)
+	{
+		/*
+		 * Back up to the beginning of the line.
+		 */
+		while ((c = ch_back_get()) != '\n' && c != EOI)
+			;
+		if (c == '\n')
+			(void) ch_forw_get();
+		pos = ch_tell();
+	}
+	if (show_attn)
+		set_attnpos(pos);
+	jump_loc(pos, sline);
+}
+
+/*
+ * Jump to a specified position in the file.
+ * The position must be the first character in a line.
+ * Place the target line on a specified line on the screen.
+ */
+	public void
+jump_loc(pos, sline)
+	POSITION pos;
+	int sline;
+{
+	register int nline;
+	POSITION tpos;
+	POSITION bpos;
+
+	/*
+	 * Normalize sline.
+	 */
+	sline = adjsline(sline);
+
+	if ((nline = onscreen(pos)) >= 0)
+	{
+		/*
+		 * The line is currently displayed.  
+		 * Just scroll there.
+		 */
+		nline -= sline;
+		if (nline > 0)
+			forw(nline, position(BOTTOM_PLUS_ONE), 1, 0, 0);
+		else
+			back(-nline, position(TOP), 1, 0);
+		if (show_attn)
+			repaint_hilite(1);
+		return;
+	}
+
+	/*
+	 * Line is not on screen.
+	 * Seek to the desired location.
+	 */
+	if (ch_seek(pos))
+	{
+		error("Cannot seek to that file position", NULL_PARG);
+		return;
+	}
+
+	/*
+	 * See if the desired line is before or after 
+	 * the currently displayed screen.
+	 */
+	tpos = position(TOP);
+	bpos = position(BOTTOM_PLUS_ONE);
+	if (tpos == NULL_POSITION || pos >= tpos)
+	{
+		/*
+		 * The desired line is after the current screen.
+		 * Move back in the file far enough so that we can
+		 * call forw() and put the desired line at the 
+		 * sline-th line on the screen.
+		 */
+		for (nline = 0;  nline < sline;  nline++)
+		{
+			if (bpos != NULL_POSITION && pos <= bpos)
+			{
+				/*
+				 * Surprise!  The desired line is
+				 * close enough to the current screen
+				 * that we can just scroll there after all.
+				 */
+				forw(sc_height-sline+nline-1, bpos, 1, 0, 0);
+				if (show_attn)
+					repaint_hilite(1);
+				return;
+			}
+			pos = back_line(pos);
+			if (pos == NULL_POSITION)
+			{
+				/*
+				 * Oops.  Ran into the beginning of the file.
+				 * Exit the loop here and rely on forw()
+				 * below to draw the required number of
+				 * blank lines at the top of the screen.
+				 */
+				break;
+			}
+		}
+		lastmark();
+		hit_eof = 0;
+		squished = 0;
+		screen_trashed = 0;
+		forw(sc_height-1, pos, 1, 0, sline-nline);
+	} else
+	{
+		/*
+		 * The desired line is before the current screen.
+		 * Move forward in the file far enough so that we
+		 * can call back() and put the desired line at the 
+		 * sline-th line on the screen.
+		 */
+		for (nline = sline;  nline < sc_height - 1;  nline++)
+		{
+			pos = forw_line(pos);
+			if (pos == NULL_POSITION)
+			{
+				/*
+				 * Ran into end of file.
+				 * This shouldn't normally happen, 
+				 * but may if there is some kind of read error.
+				 */
+				break;
+			}
+			if (pos >= tpos)
+			{
+				/* 
+				 * Surprise!  The desired line is
+				 * close enough to the current screen
+				 * that we can just scroll there after all.
+				 */
+				back(nline+1, tpos, 1, 0);
+				if (show_attn)
+					repaint_hilite(1);
+				return;
+			}
+		}
+		lastmark();
+		clear();
+		screen_trashed = 0;
+		add_back_pos(pos);
+		back(sc_height-1, pos, 1, 0);
+	}
+}