Golay18.java

package edac;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import bits.BinaryMessage;

/*******************************************************************************
 *     SDR Trunk 
 *     Copyright (C) 2014 Dennis Sheirer
 * 
 *     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 3 of the License, 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 program.  If not, see <http://www.gnu.org/licenses/>
 *     -----------------------------------------------------------------------
 *     Galois24 decoder based on Hank Wallace's tutorial/algorithm located at:
 *     http://www.aqdi.com/golay.htm
 ******************************************************************************/

/**
 * Golay 18/6/8 decoder.  Uses the Golay24 edac class to perform edac on Golay
 * 18 messages by treating the Golay 18 message as a Golay 24 message with the 
 * left-most 6 bits set to zero.
 */
public class Golay18
{
	private final static Logger mLog = LoggerFactory.getLogger( Golay18.class );

	/**
	 * Performs error detection and correction.
	 */
	public static void checkAndCorrect( BinaryMessage message, int startIndex )
	{
		int value = message.getInt( startIndex, startIndex + 17 );

		BinaryMessage temp = new BinaryMessage( 24 );
		temp.load( 6, 18, value );

		BinaryMessage corrected = Golay24.checkAndCorrect( temp, 0 );

		int correctedValue = corrected.getInt( 6, 23 );
		
		message.load( startIndex, 18, correctedValue );
	}
}