/* file: UnicodeLexer.java

Java 1.5 grammar for SableCC.

Copyright (C) 2006 by Etienne Gagnon.
All rights reserved.

This file is licensed under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance with the
License.  You should have received a copy of the License along with
This file in the file "AL20"; if not, you may obtain a copy of the
License at:

 http://www.apache.org/licenses/LICENSE-2.0

This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
CONDITIONS OF ANY KIND, either express or implied.  See the License
for the specific language governing permissions and limitations under
the License.

The SableCC web site is located at:
  http://sablecc.org
*/

import org.sablecc.grammars.java_1_5.unicodepreprocessor.lexer.*;
import org.sablecc.grammars.java_1_5.unicodepreprocessor.node.*;
import org.sablecc.grammars.java_1_5.unicodepreprocessor.analysis.*;
import java.io.*;

public class UnicodeLexer extends Lexer
{
    private PushbackReader in;
    
    public UnicodeLexer(PushbackReader in)
    {
        super(in);
        this.in = in;
    }

    private Token buffer;
    
    protected void filter()
    {
        if(state.equals(State.SUB))
	    {
		if(buffer == null)
		    {
			buffer = token;
			token = null;
		    }
		else
		    {
			if(token instanceof EOF)
			    {
				buffer = null;
				state = State.NORMAL;
			    }
			else
			    {
				try
				    {
					// Unread the last token text.
					in.unread(token.getText().toCharArray());
				    }
				catch(IOException e)
				    {
					throw new RuntimeException("Error while unreading: " + e);
				    }
				
				token = buffer;
				buffer = null;
				state = State.NORMAL;
			    }
		    }
	    }
        else
	    {
		if(token instanceof TUnicodeEscape)
		    {
			String text = token.getText();
			
			// Is it SUB?
			if(text.substring(text.length() - 4).equalsIgnoreCase("001a"))
			    {
				buffer = token;
				token = null;
				state = State.SUB;
			    }
		    }
	    }
    }
}