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/* Copyright (c) 2014, David A. Clunie DBA Pixelmed Publishing. All rights reserved. */
package com.pixelmed.codec.jpeg;
/**
* <p>A JPEG SOS Marker Segment.</p>
*
* @author dclunie
*/
public class MarkerSegmentSOS {
private static final String identString = "@(#) $Header: /userland/cvs/codec/com/pixelmed/codec/jpeg/MarkerSegmentSOS.java,v 1.2 2014/03/22 09:06:13 dclunie Exp $";
private int nComponentsPerScan;
private int[] ScanComponentSelector;
private int[] DCEntropyCodingTableSelector;
private int[] ACEntropyCodingTableSelector;
private int[] MappingTableSelector; // LS
private int StartOfSpectralOrPredictorSelection;
private int EndOfSpectralSelection;
private int SuccessiveApproximationBitPositionHigh;
private int SuccessiveApproximationBitPositionLowOrPointTransform;
public int getNComponentsPerScan() { return nComponentsPerScan; }
public int[] getDCEntropyCodingTableSelector() { return DCEntropyCodingTableSelector; }
public int[] getACEntropyCodingTableSelector() { return ACEntropyCodingTableSelector; }
public MarkerSegmentSOS(byte[] b,int length) throws Exception {
nComponentsPerScan=Utilities.extract8(b,0);
int lengthExpected = 1+nComponentsPerScan*2+3;
if (length != lengthExpected) {
throw new Exception("Incorrect length of SOS Parameters Marker Segment, expected "+lengthExpected+" (based on nComponentsPerScan "+nComponentsPerScan+") but was "+length);
}
ScanComponentSelector =new int[nComponentsPerScan];
DCEntropyCodingTableSelector=new int[nComponentsPerScan];
ACEntropyCodingTableSelector=new int[nComponentsPerScan];
MappingTableSelector =new int[nComponentsPerScan]; // LS
for (int i=0; i<nComponentsPerScan; ++i) {
ScanComponentSelector[i] =Utilities.extract8(b,1+i*2);
DCEntropyCodingTableSelector[i]=Utilities.extract8(b,1+i*2+1) >> 4;
ACEntropyCodingTableSelector[i]=Utilities.extract8(b,1+i*2+1) & 0x0f;
MappingTableSelector[i] =Utilities.extract8(b,1+i*2+1); // LS
}
StartOfSpectralOrPredictorSelection =Utilities.extract8(b,1+nComponentsPerScan*2);
EndOfSpectralSelection =Utilities.extract8(b,1+nComponentsPerScan*2+1);
SuccessiveApproximationBitPositionHigh =Utilities.extract8(b,1+nComponentsPerScan*2+2) >> 4;
SuccessiveApproximationBitPositionLowOrPointTransform=Utilities.extract8(b,1+nComponentsPerScan*2+2) & 0x0f;
}
public String toString() {
StringBuffer buf = new StringBuffer();
buf.append("\n\tSOS:\n");
buf.append("\t\t nComponentsPerScan = "+nComponentsPerScan+"\n");
for (int i=0; i<nComponentsPerScan; ++i) {
buf.append("\t\t component "+i+"\n");
buf.append("\t\t\t ScanComponentSelector = "+ScanComponentSelector[i]+"\n");
buf.append("\t\t\t DCEntropyCodingTableSelector = "+DCEntropyCodingTableSelector[i]+"\n");
buf.append("\t\t\t ACEntropyCodingTableSelector = "+ACEntropyCodingTableSelector[i]+"\n");
buf.append("\t\t\t MappingTableSelector(LS) = "+MappingTableSelector[i]+"\n"); // LS
}
buf.append("\t\t StartOfSpectralOrPredictorSelection/NearLosslessDifferenceBound(LS) = "+StartOfSpectralOrPredictorSelection+"\n");
buf.append("\t\t EndOfSpectralSelection/InterleaveMode(LS) = "+EndOfSpectralSelection+"\n");
buf.append("\t\t SuccessiveApproximationBitPositionHigh = "+SuccessiveApproximationBitPositionHigh+"\n");
return buf.toString();
}
}
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