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An Open Source JavaFX PDF Viewer
/*
* ===========================================
* Java Pdf Extraction Decoding Access Library
* ===========================================
*
* Project Info: http://www.idrsolutions.com
* Help section for developers at http://www.idrsolutions.com/support/
*
* (C) Copyright 1997-2015 IDRsolutions and Contributors.
*
* This file is part of JPedal/JPDF2HTML5
*
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* ---------------
* MQDecoder.java
* ---------------
*/
package com.idrsolutions.image.jpeg2000;
/**
*
*/
public final class MQDecoder {
/**
* The data structures containing the probabilities for the LPS
*/
public static final int QE[] = {
0x5601, 0x3401, 0x1801, 0x0ac1, 0x0521, 0x0221, 0x5601, 0x5401,
0x4801, 0x3801, 0x3001, 0x2401, 0x1c01, 0x1601, 0x5601, 0x5401,
0x5101, 0x4801, 0x3801, 0x3401, 0x3001, 0x2801, 0x2401, 0x2201,
0x1c01, 0x1801, 0x1601, 0x1401, 0x1201, 0x1101, 0x0ac1, 0x09c1,
0x08a1, 0x0521, 0x0441, 0x02a1, 0x0221, 0x0141, 0x0111, 0x0085,
0x0049, 0x0025, 0x0015, 0x0009, 0x0005, 0x0001, 0x5601
};
/**
* The indexes of the next MPS
*/
public static final byte NMPS[] = {
1, 2, 3, 4, 5, 38, 7, 8,
9, 10, 11, 12, 13, 29, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24,
25, 26, 27, 28, 29, 30, 31, 32,
33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 45, 46
};
/**
* The indexes of the next LPS
*/
public static final byte NLPS[] = {
1, 6, 9, 12, 29, 33, 6, 14,
14, 14, 17, 18, 20, 21, 14, 14,
15, 16, 17, 18, 19, 19, 20, 21,
22, 23, 24, 25, 26, 27, 28, 29,
30, 31, 32, 33, 34, 35, 36, 37,
38, 39, 40, 41, 42, 43, 46
};
/**
* Whether LPS and MPS should be switched
*/
public static final byte[] SWITCHML = {
1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0
};
//int bpst;
int bp;
int c;
int b;
int ct;
int a;
int[] i;
int[] mps;
int d;
final byte[] data;
public MQDecoder(byte[] data, int start, int end) {
this.data = data;
bp = start;
b = data[bp] & 0xff;
c = b << 16;
byteIn();
c <<= 7;
ct -= 7;
a = 0x8000;
}
public void byteIn() {
int b1 = data[bp + 1] & 0xff;
if (b == 0xff) {
if (b1 > 0x8f) {
c += 0xff00;
ct = 8;
} else {
bp ++;
b = b1;//b = buffer.get(bp) & 0xff;
c += (b << 9);
ct = 7;
}
} else {
bp ++;
b = b1;//b = buffer.get(bp) & 0xff;
c += (b << 8);
ct = 8;
}
}
public int decode(int cx) {
int qe = QE[i[cx]];
a -= qe;
int chigh = (c>>>16);
int clow = (c & 0xffff);
if(chigh < qe){
d = lpsExchange(cx);
renormalize();
}else{
chigh -= qe;
c = (chigh << 16) | clow;
if((a & 0x8000) == 0){
d = mpsExchange(cx);
renormalize();
}else{
d = mps[cx];
}
}
return d;
}
public int mpsExchange(int cx) {
if (a < QE[i[cx]]) {
d = 1 - mps[cx];
if (SWITCHML[i[cx]] == 1) {
mps[cx] = 1 - mps[cx];
}
i[cx] = NLPS[i[cx]];
} else {
d = mps[cx];
i[cx] = NMPS[i[cx]];
}
return d;
}
public int lpsExchange(int cx) {
if (a < QE[i[cx]]) {
a = QE[i[cx]];
d = mps[cx];
i[cx] = NMPS[i[cx]];
} else {
a = QE[i[cx]];
d = 1 - mps[cx];
if (SWITCHML[i[cx]] == 1) {
mps[cx] = 1 - mps[cx];
}
i[cx] = NLPS[i[cx]];
}
return d;
}
public void renormalize(){
do {
if (ct == 0) {
byteIn();
}
a <<= 1;
c <<= 1;
ct--;
} while ((a & 0x8000)==0);
}
}