org.glassfish.grizzly.compression.lzma.impl.rangecoder.BitTreeDecoder Maven / Gradle / Ivy
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package org.glassfish.grizzly.compression.lzma.impl.rangecoder;
import org.glassfish.grizzly.compression.lzma.LZMADecoder;
/**
* BitTreeDecoder
*
* @author Igor Pavlov
*/
public class BitTreeDecoder {
short[] Models;
int NumBitLevels;
// decode state
int decodeMethodState;
int m;
int bitIndex;
// reverseDecode state
int reverseDecodeMethodState;
int symbol;
public BitTreeDecoder(int numBitLevels) {
NumBitLevels = numBitLevels;
Models = new short[1 << numBitLevels];
}
public void init() {
decodeMethodState = 0;
reverseDecodeMethodState = 0;
RangeDecoder.initBitModels(Models);
}
public boolean decode(LZMADecoder.LZMAInputState decodeState,
RangeDecoder rangeDecoder) throws java.io.IOException {
do {
switch(decodeMethodState) {
case 0:
{
m = 1;
bitIndex = NumBitLevels;
decodeMethodState = 1;
}
case 1:
{
if (bitIndex == 0) {
decodeMethodState = 3;
continue;
}
decodeMethodState = 2;
}
case 2:
{
if (!rangeDecoder.decodeBit(decodeState, Models, m)) {
return false;
}
m = (m << 1) + decodeState.lastMethodResult;
bitIndex--;
decodeMethodState = 1;
continue;
}
case 3:
{
decodeState.lastMethodResult = m - (1 << NumBitLevels);
decodeMethodState = 0;
return true;
}
}
} while (true);
}
public boolean reverseDecode(LZMADecoder.LZMAInputState decodeState,
RangeDecoder rangeDecoder) throws java.io.IOException {
do {
switch(reverseDecodeMethodState) {
case 0:
{
m = 1;
symbol = 0;
bitIndex = 0;
reverseDecodeMethodState = 1;
}
case 1:
{
if (bitIndex >= NumBitLevels) {
reverseDecodeMethodState = 3;
continue;
}
reverseDecodeMethodState = 2;
}
case 2:
{
if (!rangeDecoder.decodeBit(decodeState, Models, m)) {
return false;
}
final int bit = decodeState.lastMethodResult;
m <<= 1;
m += bit;
symbol |= (bit << bitIndex);
bitIndex++;
reverseDecodeMethodState = 1;
continue;
}
case 3:
{
decodeState.lastMethodResult = symbol;
reverseDecodeMethodState = 0;
return true;
}
}
} while (true);
}
public static boolean reverseDecode(LZMADecoder.LZMAInputState decodeState,
short[] Models, int startIndex, RangeDecoder rangeDecoder,
int NumBitLevels) throws java.io.IOException {
do {
switch(decodeState.staticReverseDecodeMethodState) {
case 0:
{
decodeState.staticM = 1;
decodeState.staticSymbol = 0;
decodeState.staticBitIndex = 0;
decodeState.staticReverseDecodeMethodState = 1;
}
case 1:
{
if (decodeState.staticBitIndex >= NumBitLevels) {
decodeState.staticReverseDecodeMethodState = 3;
continue;
}
decodeState.staticReverseDecodeMethodState = 2;
}
case 2:
{
if (!rangeDecoder.decodeBit(decodeState, Models,
startIndex + decodeState.staticM)) {
return false;
}
final int bit = decodeState.lastMethodResult;
decodeState.staticM <<= 1;
decodeState.staticM += bit;
decodeState.staticSymbol |= (bit << decodeState.staticBitIndex);
decodeState.staticBitIndex++;
decodeState.staticReverseDecodeMethodState = 1;
continue;
}
case 3:
{
decodeState.lastMethodResult = decodeState.staticSymbol;
decodeState.staticReverseDecodeMethodState = 0;
return true;
}
}
} while (true);
}
}