/**
 * $Id$
 * 
 * Title: tn5250J
 * Copyright:   Copyright (c) 2001,2009
 * Company:
 * @author: master_jaf
 *
 * Description:
 *
 * 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, or (at your option)
 * 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 software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA
 *
 */
package org.tn5250j.encoding.builtin;

import java.util.Arrays;

/**
 * Adapter class for converters using 8bit codepages.
 * 
 * @author master_jaf
 */
public abstract class CodepageConverterAdapter implements ICodepageConverter {
	
	private char[] codepage = null;
	private int[] reverse_codepage = null;
	
	/* (non-Javadoc)
	 * @see org.tn5250j.cp.ICodepageConverter#init()
	 */
	public ICodepageConverter init() {
		codepage = getCodePage();
		
		int size = 0;
		for (int i=0; i<codepage.length; i++) {
			size = Math.max(size, codepage[i]);
		}
		assert (size + 1) < 1024*1024; // some kind of maximum size limiter.
		reverse_codepage = new int[size+1];
		Arrays.fill(reverse_codepage, '?');
		for (int i=0; i<codepage.length; i++) {
			reverse_codepage[codepage[i]] = i;
		}
		return this;
	}
	
	/* (non-Javadoc)
	 * @see org.tn5250j.cp.ICodepageConverter#uni2ebcdic(char)
	 */
	public byte uni2ebcdic(char index) {
		assert index < reverse_codepage.length;
		return (byte)reverse_codepage[index];
	}
	
	/* (non-Javadoc)
	 * @see org.tn5250j.cp.ICodepageConverter#ebcdic2uni(int)
	 */
	public char ebcdic2uni(int index) {
		index = index & 0xFF;
		assert index < 256;
		return codepage[index];
	}

	/**
	 * @return The oringal 8bit codepage. 
	 */
	protected abstract char[] getCodePage();
	
}