Editor/Embedded/ZstdSharp/Unsafe/Methods.Fse.cs
Unsafe helper methods for FSE (Finite State Entropy) decoding used by the embedded ZstdSharp library in the Editor assembly. It initializes an FSE decode state and decodes symbols from a bit stream with normal and "fast" variants, using unsafe pointers and bit-reading helpers.
Native InteropObfuscated Code
#nullable enable
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using static HumanoidRetargeter.EditorTools.Embedded.ZstdSharp.UnsafeHelper;
namespace HumanoidRetargeter.EditorTools.Embedded.ZstdSharp.Unsafe;
public static unsafe partial class Methods
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static void FSE_initDState(ref FSE_DState_t DStatePtr, ref BIT_DStream_t bitD, uint* dt)
{
void* ptr = dt;
FSE_DTableHeader* DTableH = (FSE_DTableHeader*)ptr;
DStatePtr.state = BIT_readBits(bitD.bitContainer, ref bitD.bitsConsumed, DTableH->tableLog);
BIT_reloadDStream(ref bitD.bitContainer, ref bitD.bitsConsumed, ref bitD.ptr, bitD.start, bitD.limitPtr);
DStatePtr.table = dt + 1;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static byte FSE_decodeSymbol(ref FSE_DState_t DStatePtr, nuint bitD_bitContainer, ref uint bitD_bitsConsumed)
{
FSE_decode_t DInfo = ((FSE_decode_t*)DStatePtr.table)[DStatePtr.state];
uint nbBits = DInfo.nbBits;
byte symbol = DInfo.symbol;
nuint lowBits = BIT_readBits(bitD_bitContainer, ref bitD_bitsConsumed, nbBits);
DStatePtr.state = DInfo.newState + lowBits;
return symbol;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static byte FSE_decodeSymbolFast(ref FSE_DState_t DStatePtr, nuint bitD_bitContainer, ref uint bitD_bitsConsumed)
{
FSE_decode_t DInfo = ((FSE_decode_t*)DStatePtr.table)[DStatePtr.state];
uint nbBits = DInfo.nbBits;
byte symbol = DInfo.symbol;
nuint lowBits = BIT_readBitsFast(bitD_bitContainer, ref bitD_bitsConsumed, nbBits);
DStatePtr.state = DInfo.newState + lowBits;
return symbol;
}
}