/jEdit/tags/jedit-4-0-pre5/org/gjt/sp/jedit/buffer/IndentFoldHandler.java

/*
 * IndentFoldHandler.java - Indent-based fold handler
 * :tabSize=8:indentSize=8:noTabs=false:
 * :folding=explicit:collapseFolds=1:
 *
 * Copyright (C) 2001 Slava Pestov
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package org.gjt.sp.jedit.buffer;

import javax.swing.text.Segment;
import org.gjt.sp.jedit.Buffer;

/**
 * A fold handler that folds lines based on their indent level.
 * @author Slava Pestov
 * @version $Id: IndentFoldHandler.java 3996 2002-01-26 01:36:25Z spestov $
 * @since jEdit 4.0pre1
 */
public class IndentFoldHandler implements FoldHandler
{
	//{{{ getFoldLevel() method
	/**
	 * Returns the fold level of the specified line.
	 * @param buffer The buffer in question
	 * @param lineIndex The line index
	 * @param seg A segment the fold handler can use to obtain any
	 * text from the buffer, if necessary
	 * @return The fold level of the specified line
	 * @since jEdit 4.0pre1
	 */
	public int getFoldLevel(Buffer buffer, int lineIndex, Segment seg)
	{
		int tabSize = buffer.getTabSize();

		buffer.getLineText(lineIndex,seg);

		int offset = seg.offset;
		int count = seg.count;

		int whitespace = 0;

		if(count == 0)
		{
			// empty line. inherit previous line's fold level
			if(lineIndex != 0)
				whitespace = buffer.getFoldLevel(lineIndex - 1);
			else
				whitespace = 0;
		}
		else
		{
loop:			for(int i = 0; i < count; i++)
			{
				switch(seg.array[offset + i])
				{
				case ' ':
					whitespace++;
					break;
				case '\t':
					whitespace += (tabSize - whitespace % tabSize);
					break;
				default:
					break loop;
				}
			}
		}

		return whitespace;
	} //}}}
}