/*******************************************************************************
* 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;
import org.apache.commons.lang3.Validate;
import java.util.ArrayList;
import java.util.List;
/**
* Multi-Sync pattern matcher. Accepts multiple sync detector objects for
* comparision against the incoming bit stream.
*
* 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 Long.rotate methods will wrap the MSB around to the LSB and
* corrupt the matching value.
*
*/
public class MultiSyncPatternMatcher
{
private List<ISyncProcessor> mSyncProcessors = new ArrayList<ISyncProcessor>();
private long mBits = 0;
private long mMask = 0;
public MultiSyncPatternMatcher( int syncSize )
{
Validate.isTrue(syncSize < 64);
//Setup a bit mask of all ones the length of the sync pattern
mMask = (long)( ( Math.pow( 2, syncSize ) ) - 1 );
}
public void dispose()
{
mSyncProcessors.clear();
}
/**
* Processes two bits before checking sync processors for a match.
*/
public void receive( boolean bit1, boolean bit2 )
{
mBits = Long.rotateLeft( mBits, 1 );
mBits &= mMask;
if( bit1 )
{
mBits += 1;
}
mBits = Long.rotateLeft( mBits, 1 );
mBits &= mMask;
if( bit2 )
{
mBits += 1;
}
for( ISyncProcessor processor: mSyncProcessors )
{
processor.checkSync( mBits );
}
}
/**
* Processes one bit before checking sync processors for a match.
*/
public void receive( boolean bit )
{
mBits = Long.rotateLeft( mBits, 1 );
mBits &= mMask;
if( bit )
{
mBits += 1;
}
for( ISyncProcessor processor: mSyncProcessors )
{
processor.checkSync( mBits );
}
}
/**
* Adds a sync processor to receive the bit stream.
*/
public void add( ISyncProcessor processor )
{
mSyncProcessors.add( processor );
}
}