mirror of
https://github.com/DSheirer/sdrtrunk.git
synced 2026-11-12 16:47:31 -05:00
104 lines
2.8 KiB
Java
104 lines
2.8 KiB
Java
package edac;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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import bits.BitSetBuffer;
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/*******************************************************************************
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* SDR Trunk
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* Copyright (C) 2014 Dennis Sheirer
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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******************************************************************************/
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public class BCH_63_16_11 extends BerlekempMassey_63
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{
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private final static Logger mLog = LoggerFactory.getLogger( BCH_63_16_11.class );
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/**
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* BCH( 63,16,11) decoder
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*/
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public BCH_63_16_11()
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{
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/* TT = 11 = maximum correctable bit errors */
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super( 11 );
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}
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/**
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* Performs error detection and correction on the first 63 bits of the
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* message argument. If the message is correctable, only the first 16 bits
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* (information bits) are corrected.
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*
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* @return - true = success, false = failure
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*/
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public CRC correctNID( BitSetBuffer message )
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{
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CRC status = CRC.PASSED;
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int[] original = message.toReverseIntegerArray();
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int[] corrected = new int[ 63 ];
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boolean irrecoverableErrors = decode( original, corrected );
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if( irrecoverableErrors )
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{
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return CRC.FAILED_CRC;
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}
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else
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{
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for( int x = 0; x < 16; x++ )
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{
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int index = 63 - x - 1;
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if( corrected[ index ] != original[ index ] )
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{
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status = CRC.CORRECTED;
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if( corrected[ index ] == 1 )
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{
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message.set( x );
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}
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else
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{
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message.clear( x );
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}
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}
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}
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}
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return status;
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}
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public static void main( String[] args )
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{
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String orig = "001001100000110010100101011111010001010101101001111111001010110";
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String error = "010110000000110010100101011011010001011101101001101111001110110";
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// xxxxxx x x x x
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BitSetBuffer errorMessage = BitSetBuffer.load( error );
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BCH_63_16_11 bch = new BCH_63_16_11();
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mLog.debug( "ORIG:" + orig );
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mLog.debug( " ERR:" + errorMessage.toString() );
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mLog.debug( " " );
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CRC status = bch.correctNID( errorMessage );
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mLog.debug( " CRC: " + status.name() );
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mLog.debug( "CORR:" + errorMessage.toString().substring( 0, 16 ) );
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mLog.debug( "ORIG:" + orig );
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}
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}
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