/*
* IndentFoldHandler.java - Indent-based fold handler
* :tabSize=4:indentSize=4:noTabs=false:
* :folding=explicit:collapseFolds=1:
*
* Copyright (C) 2001, 2002 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 java.util.ArrayList;
import java.util.List;
import javax.swing.text.Segment;
/**
* A fold handler that folds lines based on their indent level.
* @author Slava Pestov
* @version $Id$
* @since jEdit 4.0pre1
*/
public class IndentFoldHandler extends FoldHandler
{
public IndentFoldHandler()
{
super("indent");
}
// Returns the width of leading whitespace in the given segment
// if it contains non-whitespace characters, or (-1) otherwise.
private int getLeadingWhitespaceWidth(Segment seg, int tabSize)
{
int offset = seg.offset;
int count = seg.count;
int whitespace = 0;
for(int i = 0; i < count; i++)
{
switch(seg.array[offset + i])
{
case ' ':
whitespace++;
break;
case '\t':
whitespace += (tabSize - whitespace % tabSize);
break;
default:
return whitespace;
}
}
return (-1);
}
//{{{ getFoldLevel() method
/**
* Returns the fold level of the specified line. For a whitespace-only
* line, returns the fold level of the next non-whitespace line, or
* the level of the previous line if no non-whitespace line follows or if
* the level of the previous line is higher.
* @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(JEditBuffer buffer, int lineIndex, Segment seg)
{
int tabSize = buffer.getTabSize();
// Look for first non-whitespace line starting at lineIndex
int prevLevel = 0;
for (int index = lineIndex; index < buffer.getLineCount(); index++)
{
buffer.getLineText(index,seg);
int whitespace = getLeadingWhitespaceWidth(seg,tabSize);
if(whitespace >= 0) // Non-whitespace found on line
return (whitespace > prevLevel) ? whitespace : prevLevel;
if(index == 0)
return 0;
if(index == lineIndex)
prevLevel = buffer.getFoldLevel(lineIndex - 1);
}
// All lines from lineIndex are whitespace-only - use fold
// level of previous line.
return prevLevel;
} //}}}
//{{{ getPrecedingFoldLevels() method
/**
* Returns the fold levels of the lines preceding the specified line,
* which depend on 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
* @param lineFoldLevel The fold level of the specified line
* @return The fold levels of the preceding lines, in decreasing line
* number order (i.e. bottomost line first).
* @since jEdit 4.3pre18
*/
public List<Integer> getPrecedingFoldLevels(JEditBuffer buffer,
int lineIndex, Segment seg, int lineFoldLevel)
{
List<Integer> precedingFoldLevels = new ArrayList<Integer>();
int tabSize = buffer.getTabSize();
int whitespace = 0;
int index;
// Find previous non-whitespace-only line
for (index = lineIndex - 1; index > 0; index--)
{
buffer.getLineText(index,seg);
whitespace = getLeadingWhitespaceWidth(seg,tabSize);
if (whitespace >= 0)
break;
}
int max = (lineFoldLevel > whitespace) ? lineFoldLevel : whitespace;
for (index++; index < lineIndex; index++)
precedingFoldLevels.add(Integer.valueOf(max));
return precedingFoldLevels;
}
//}}}
}