bits.MultiSyncPatternMatcher.java Source code

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Here is the source code for bits.MultiSyncPatternMatcher.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;

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);
    }
}