Adds new LJ1200 decoder for potential FSK signals that may be operating on 173.075 in the US

src/decode/lj1200/LJ1200Message.java

@@ -0,0 +1,202 @@
+/*******************************************************************************
+ *     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/>
+ ******************************************************************************/
+package decode.lj1200;
+
+import java.text.SimpleDateFormat;
+import java.util.BitSet;
+import java.util.Date;
+
+import map.Plottable;
+import message.Message;
+import alias.Alias;
+import alias.AliasList;
+import bits.BitSetBuffer;
+import crc.CRC;
+import crc.CRCFleetsync;
+
+public class LJ1200Message extends Message
+{
+	public static int[] SYNC = { 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 };
+
+	public static int[] MESSAGE = { 16,17,18,19,20,21,22,23,
+		                            24,25,26,27,28,29,30,31,
+		                            32,33,34,35,36,37,38,39,
+		                            40,41,42,43,44,45,46,47,
+		                            48,49,50,51,52,53,54,55,
+		                            56,57,58,59,60,61,62,63 };
+
+	public static int[] CRC = { 64,65,66,67,68,69,70,71,
+		                        72,73,74,75,76,77,78,79 };
+	
+	private static SimpleDateFormat mSDF = new SimpleDateFormat( "yyyyMMdd HHmmss" );
+
+    private BitSetBuffer mMessage;
+    private AliasList mAliasList;
+    private CRC mCRC;
+    
+    public LJ1200Message( BitSetBuffer message, AliasList list )
+    {
+        mMessage = message;
+        mAliasList = list;
+        checkParity();
+    }
+    
+    private void checkParity()
+    {
+    	mCRC = detectAndCorrect( 16, 79 );
+    }
+    
+    private CRC detectAndCorrect( int start, int end )
+    {
+    	BitSet original = mMessage.get( start, end );
+
+    	CRC crc = CRCFleetsync.check( original );
+
+    	if( crc == crc.FAILED_PARITY )
+    	{
+    		int[] errorBitPositions = CRCFleetsync.findBitErrors( original );
+    		
+    		if( errorBitPositions != null )
+    		{
+    			for( int errorBitPosition: errorBitPositions )
+    			{
+    				mMessage.flip( start + errorBitPosition );
+    			}
+    			
+    			crc = crc.CORRECTED;
+    		}
+    	}
+    	
+    	return crc;
+    }
+    
+    public boolean isValid()
+    {
+    	return true;
+    }
+    
+    @Override
+    public String toString()
+    {
+    	StringBuilder sb = new StringBuilder();
+
+    	sb.append( mSDF.format( new Date( System.currentTimeMillis() ) ) );
+
+    	sb.append( " LJ1200 [" );
+    	sb.append( mMessage.toString() );
+    	sb.append( "]" );
+
+    	return sb.toString();
+    }
+
+    /**
+     * Pads spaces onto the end of the value to make it 'places' long
+     */
+    public String pad( String value, int places, String padCharacter )
+    {
+    	StringBuilder sb = new StringBuilder();
+    	
+    	sb.append( value );
+    	
+    	while( sb.length() < places )
+    	{
+    		sb.append( padCharacter );
+    	}
+    	
+    	return sb.toString();
+    }
+    
+    /**
+     * Pads an integer value with additional zeroes to make it decimalPlaces long
+     */
+    public String format( int number, int decimalPlaces )
+    {
+    	StringBuilder sb = new StringBuilder();
+
+    	int paddingRequired = decimalPlaces - ( String.valueOf( number ).length() );
+
+    	for( int x = 0; x < paddingRequired; x++)
+    	{
+    		sb.append( "0" );
+    	}
+    	
+    	sb.append( number );
+    	
+    	return sb.toString();
+    }
+    
+	@Override
+    public String getBinaryMessage()
+    {
+		return mMessage.toString();
+	}
+
+	@Override
+    public String getProtocol()
+    {
+	    return "LJ 1200";
+    }
+
+	@Override
+    public String getEventType()
+    {
+	    return "MESSAGE";
+    }
+
+	@Override
+    public String getFromID()
+    {
+		return null;
+    }
+
+	@Override
+    public Alias getFromIDAlias()
+    {
+		return null;
+    }
+
+	@Override
+	public String getToID()
+	{
+	    return null;
+	}
+
+	@Override
+    public Alias getToIDAlias()
+    {
+		return null;
+    }
+	
+	@Override
+    public String getMessage()
+    {
+		return toString();
+    }
+	
+	@Override
+    public String getErrorStatus()
+    {
+	    return "UNKNOWN";
+    }
+
+	@Override
+    public Plottable getPlottable()
+    {
+		return null;
+    }
+}