public static int DecompressUsingTable(ReadOnlySpan <byte> source, Span <byte> destination, FseDecompressTableHeader header, ReadOnlySpan <FseDecompressTable> decodeTable)
{
int destinationLength = destination.Length;
var reader = new FseBitReader(source);
var state1 = FseDecompressState.Initialize(ref reader, header, decodeTable);
var state2 = FseDecompressState.Initialize(ref reader, header, decodeTable);
while (destination.Length >= 16)
{
ref byte destinationRef = ref MemoryMarshal.GetReference(destination);
destinationRef = state1.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 1) = state2.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 2) = state1.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 3) = state2.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 4) = state1.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 5) = state2.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 6) = state1.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 7) = state2.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 8) = state1.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 9) = state2.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 10) = state1.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 11) = state2.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 12) = state1.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 13) = state2.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 14) = state1.DecodeSymbol(ref reader);
Unsafe.Add(ref destinationRef, 15) = state2.DecodeSymbol(ref reader);
destination = destination.Slice(16);
}
public void UpdateState(ref FseBitReader reader)
{
FseDecompressTable dInfo = Table[State];
uint lowBits = reader.ReadBits(dInfo.NumberOfBits);
State = (int)(dInfo.NewState + lowBits);
}
public byte DecodeSymbol(ref FseBitReader reader)
{
FseDecompressTable dInfo = Table[State];
uint lowBits = reader.ReadBits(dInfo.NumberOfBits);
State = (int)(dInfo.NewState + lowBits);
return(dInfo.Symbol);
}
public static FseDecompressState Initialize(ref FseBitReader reader, FseDecompressTableHeader header, ReadOnlySpan <FseDecompressTable> dt)
{
FseDecompressState fse = default;
fse.Table = dt;
fse.State = (int)reader.ReadBits(header.TableLog);
return(fse);
}
