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package SevenZip.Compression.RangeCoder;
import java.io.IOException;
public class BitTreeEncoder
{
short[] Models;
int NumBitLevels;
public BitTreeEncoder(int numBitLevels)
{
NumBitLevels = numBitLevels;
Models = new short[1 << numBitLevels];
}
public void Init()
{
Decoder.InitBitModels(Models);
}
public void Encode(Encoder rangeEncoder, int symbol) throws IOException
{
int m = 1;
for (int bitIndex = NumBitLevels; bitIndex != 0; )
{
bitIndex--;
int bit = (symbol >>> bitIndex) & 1;
rangeEncoder.Encode(Models, m, bit);
m = (m << 1) | bit;
}
}
public void ReverseEncode(Encoder rangeEncoder, int symbol) throws IOException
{
int m = 1;
for (int i = 0; i < NumBitLevels; i++)
{
int bit = symbol & 1;
rangeEncoder.Encode(Models, m, bit);
m = (m << 1) | bit;
symbol >>= 1;
}
}
public int GetPrice(int symbol)
{
int price = 0;
int m = 1;
for (int bitIndex = NumBitLevels; bitIndex != 0; )
{
bitIndex--;
int bit = (symbol >>> bitIndex) & 1;
price += Encoder.GetPrice(Models[m], bit);
m = (m << 1) + bit;
}
return price;
}
public int ReverseGetPrice(int symbol)
{
int price = 0;
int m = 1;
for (int i = NumBitLevels; i != 0; i--)
{
int bit = symbol & 1;
symbol >>>= 1;
price += Encoder.GetPrice(Models[m], bit);
m = (m << 1) | bit;
}
return price;
}
public static int ReverseGetPrice(short[] Models, int startIndex,
int NumBitLevels, int symbol)
{
int price = 0;
int m = 1;
for (int i = NumBitLevels; i != 0; i--)
{
int bit = symbol & 1;
symbol >>>= 1;
price += Encoder.GetPrice(Models[startIndex + m], bit);
m = (m << 1) | bit;
}
return price;
}
public static void ReverseEncode(short[] Models, int startIndex,
Encoder rangeEncoder, int NumBitLevels, int symbol) throws IOException
{
int m = 1;
for (int i = 0; i < NumBitLevels; i++)
{
int bit = symbol & 1;
rangeEncoder.Encode(Models, startIndex + m, bit);
m = (m << 1) | bit;
symbol >>= 1;
}
}
}
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