public uint Decode(Decoder rangeDecoder)
{
uint newBound = (rangeDecoder.Range >> kNumBitModelTotalBits)*Prob;
if (rangeDecoder.Code < newBound)
{
rangeDecoder.Range = newBound;
Prob += (kBitModelTotal - Prob) >> kNumMoveBits;
if (rangeDecoder.Range < Decoder.kTopValue)
{
rangeDecoder.Code = (rangeDecoder.Code << 8) | (byte) rangeDecoder.Stream.ReadByte();
rangeDecoder.Range <<= 8;
}
return 0;
}
else
{
rangeDecoder.Range -= newBound;
rangeDecoder.Code -= newBound;
Prob -= (Prob) >> kNumMoveBits;
if (rangeDecoder.Range < Decoder.kTopValue)
{
rangeDecoder.Code = (rangeDecoder.Code << 8) | (byte) rangeDecoder.Stream.ReadByte();
rangeDecoder.Range <<= 8;
}
return 1;
}
}
public uint Decode(Decoder rangeDecoder)
{
uint m = 1;
for (int bitIndex = NumBitLevels; bitIndex > 0; bitIndex--)
m = (m << 1) + Models[m].Decode(rangeDecoder);
return m - ((uint) 1 << NumBitLevels);
}
public uint ReverseDecode(Decoder rangeDecoder)
{
uint m = 1;
uint symbol = 0;
for (int bitIndex = 0; bitIndex < NumBitLevels; bitIndex++)
{
uint bit = Models[m].Decode(rangeDecoder);
m <<= 1;
m += bit;
symbol |= (bit << bitIndex);
}
return symbol;
}
public static uint ReverseDecode(BitDecoder[] Models, UInt32 startIndex,
Decoder rangeDecoder, int NumBitLevels)
{
uint m = 1;
uint symbol = 0;
for (int bitIndex = 0; bitIndex < NumBitLevels; bitIndex++)
{
uint bit = Models[startIndex + m].Decode(rangeDecoder);
m <<= 1;
m += bit;
symbol |= (bit << bitIndex);
}
return symbol;
}