/* file: UnicodePreprocessor.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 UnicodePreprocessor extends Reader
{
    private UnicodeLexer lexer;
    private ProcessToken processor = new ProcessToken();
    
    public UnicodePreprocessor(PushbackReader in)
    {
        lexer = new UnicodeLexer(in);
    }
    
    public int read() throws IOException
    {
        if(available == 0)
	    {
		try
		    {
			lexer.next().apply(processor);
		    }
		catch(LexerException e)
		    {
			throw new RuntimeException(e.toString());
		    }
	    }
	
        if(available == 0)
	    {
		return -1;
	    }
	
        char c = buffer[0];
        buffer[0] = buffer[1];
        available--;
	
        return c;
    }
    
    public int read(
		    char cbuf[],
		    int off,
		    int len) throws IOException
    {
        for(int i = 0; i <len; i++)
	    {
		int c = read();
		
		if(c == -1)
		    {
			if(i == 0)
			    {
				return -1;
			    }
			else
			    {
				return i;
			    }
		    }
		
		cbuf[off + i] = (char) c;
	    }
	
        return len;
    }

    int available;
    char[] buffer = new char[2];
    
    private class ProcessToken extends AnalysisAdapter
    {
        public void caseTEvenBackslash(TEvenBackslash node)
        {
            buffer[0] = '\\';
            buffer[1] = '\\';
            available = 2;
        }
	
        public void caseTUnicodeEscape(TUnicodeEscape node)
        {
            String text = node.getText();
            buffer[0] = (char) Integer.parseInt(text.substring(text.length() - 4), 16);
            available = 1;
        }
	
        public void caseTErroneousEscape(TErroneousEscape node)
        {
            throw new RuntimeException("Erroneous escape: " + node);
        }
	
        public void caseTSub(TSub node)
        {
            buffer[0] = node.getText().charAt(0);
            available = 1;
        }
	
        public void caseTRawInputCharacter(TRawInputCharacter node)
        {
            buffer[0] = node.getText().charAt(0);
            available = 1;
        }
	
        public void caseEOF(EOF node)
        {
            available = 0;
        }
    }
    
    public void close()
    {
    }
}