BalancedCharacterMatcher.java

/**
 * This file Copyright (c) 2005-2008 Aptana, Inc. This program is
 * dual-licensed under both the Aptana Public License and the GNU General
 * Public license. You may elect to use one or the other of these licenses.
 * 
 * This program is distributed in the hope that it will be useful, but
 * AS-IS and WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, TITLE, or
 * NONINFRINGEMENT. Redistribution, except as permitted by whichever of
 * the GPL or APL you select, is prohibited.
 *
 * 1. For the GPL license (GPL), you can redistribute and/or modify this
 * program under the terms of the GNU General Public License,
 * Version 3, as published by the Free Software Foundation.  You should
 * have received a copy of the GNU General Public License, Version 3 along
 * with this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 * 
 * Aptana provides a special exception to allow redistribution of this file
 * with certain other free and open source software ("FOSS") code and certain additional terms
 * pursuant to Section 7 of the GPL. You may view the exception and these
 * terms on the web at http://www.aptana.com/legal/gpl/.
 * 
 * 2. For the Aptana Public License (APL), this program and the
 * accompanying materials are made available under the terms of the APL
 * v1.0 which accompanies this distribution, and is available at
 * http://www.aptana.com/legal/apl/.
 * 
 * You may view the GPL, Aptana's exception and additional terms, and the
 * APL in the file titled license.html at the root of the corresponding
 * plugin containing this source file.
 * 
 * Any modifications to this file must keep this entire header intact.
 */
package com.aptana.ide.lexer.matcher;


/**
 * @author Kevin Lindsey
 */
public class BalancedCharacterMatcher extends AbstractTextMatcher
{
	private char _startCharacter;
	private char _endCharacter;
	private int _startingCount;
	private boolean _matchEndOfFile;

	/**
	 * SingleCharacterMatcher
	 */
	public BalancedCharacterMatcher()
	{
	}
	
	/**
	 * SingleCharacterMatcher
	 * 
	 * @param c
	 */
	public BalancedCharacterMatcher(char startCharacter, char endCharacter)
	{
		this._startCharacter = startCharacter;
		this._endCharacter = endCharacter;
	}
	
	/**
	 * @see com.aptana.ide.lexer.matcher.AbstractTextMatcher#addChildTypes()
	 */
	public void addChildTypes()
	{
	}
	
	/**
	 * @see com.aptana.ide.lexer.matcher.AbstractTextMatcher#addFirstCharacters(com.aptana.ide.lexer.matcher.MatcherMap, com.aptana.ide.lexer.matcher.ITextMatcher)
	 */
	public void addFirstCharacters(MatcherMap map, ITextMatcher target)
	{
		// any character may precede a delimiter
		map.addUncategorizedMatcher(target);
	}
	
	/**
	 * @see com.aptana.ide.lexer.matcher.AbstractTextMatcher#match(char[], int, int)
	 */
	public int match(char[] source, int offset, int eofOffset)
	{
		int result = -1;
		int count = this._startingCount;
		
		while (offset < eofOffset)
		{
			char c = source[offset];
			
			if (c == this._startCharacter)
			{
				count++;
			}
			else if (c == this._endCharacter)
			{
				count--;
			}
			
			if (count == 0)
			{
				result = offset + 1;
				break;
			}
			
			offset++;
		}
		
		// update result to eof offset, if we allow EOF matching
		if (result == -1 && this._matchEndOfFile && offset == eofOffset)
		{
			result = eofOffset;
		}
		
		if (result != -1)
		{
			this.accept(source, offset, result, this.token);
		}
		
		return result;
	}
	
	/**
	 * setEndCharacter
	 * 
	 * @param endCharacter
	 */
	public void setEndCharacter(String endCharacter)
	{
		if (endCharacter != null && endCharacter.length() > 0)
		{
			this._endCharacter = endCharacter.charAt(0);
		}
	}

	/**
	 * setStartCharacter
	 * 
	 * @param startCharacter
	 */
	public void setStartCharacter(String startCharacter)
	{
		if (startCharacter != null && startCharacter.length() > 0)
		{
			this._startCharacter = startCharacter.charAt(0);
		}
	}
	
	/**
	 * setMatchEndOfFile
	 * 
	 * @param value
	 */
	public void setMatchEndOfFile(boolean value)
	{
		this._matchEndOfFile = value;
	}
	
	/**
	 * setStartingCount
	 * 
	 * @param count
	 */
	public void setStartingCount(int count)
	{
		this._startingCount = count;
	}

	/**
	 * @see com.aptana.ide.lexer.matcher.AbstractTextMatcher#validateLocal()
	 */
	protected void validateLocal()
	{
		super.validateLocal();
		
		if (this._startCharacter == '\0')
		{
			this.getDocument().sendError(Messages.BalancedCharacterMatcher_Start_Char_Not_Defined, this);
		}
		else if (this._endCharacter == '\0')
		{
			this.getDocument().sendWarning(Messages.BalancedCharacterMatcher_End_Char_Not_Defined, this);
		}
	}
}