Initial code check in continued

src/bits/SyncPatternMatcher.java

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+/*******************************************************************************
+ *     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 bits;
+
+
+/**
+ * Sync pattern matcher.
+ * 
+ * Note: works for sync patterns up to 63 bits (integer size - 1 ) long.  
+ * If a 64 bit or larger sync pattern is applied, then the wrapping feature
+ * of the Integer.rotate methods will wrap the MSB around to the LSB and
+ * corrupt the matching value.
+ *
+ */
+public class SyncPatternMatcher
+{
+	private long mBits = 0;
+	private long mMask = 0;
+	private long mSync = 0;
+	
+	public SyncPatternMatcher( boolean[] syncPattern )
+	{
+		//Setup a bit mask of all ones the length of the sync pattern
+		mMask = (long)( ( Math.pow( 2, syncPattern.length ) ) - 1 );
+		
+		//Convert the sync bits into a long value for comparison
+		for( int x = 0; x < syncPattern.length; x++ )
+		{
+			if( syncPattern[ x ] )
+			{
+    			mSync += 1l << ( syncPattern.length - 1 - x );
+			}
+		}
+	}
+	
+	public void receive( boolean bit )
+	{
+		//Left shift the previous value
+		mBits = Long.rotateLeft( mBits, 1 );
+		
+		//Apply the mask to erase the previous MSB
+		mBits &= mMask;
+		
+		//Add in the new bit
+		if( bit )
+		{
+			mBits += 1;
+		}
+	}
+
+	/**
+	 * Indicates if the most recently received bit sequence matches the 
+	 * sync pattern
+	 */
+	public boolean matches()
+	{
+		return ( mBits == mSync );
+	}
+}