using System.Runtime.CompilerServices;
using System.Numerics;

public unsafe class C {
    
    public unsafe struct BIT_DStream_t
    {
        public nuint bitContainer;
        public uint bitsConsumed;
        public sbyte* ptr;
        public sbyte* start;
        public sbyte* limitPtr;
    }
    
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    private static nuint BIT_initDStream1(ref BIT_DStream_t bitD, void* srcBuffer, nuint srcSize)
    {
        byte lastByte = ((byte*)srcBuffer)[srcSize - 1];
        bitD.bitsConsumed = lastByte != 0 ? 8 - (uint)BitOperations.Log2(lastByte) : 0;
        
        return 0;
    }
    
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    private static nuint BIT_initDStream2(ref BIT_DStream_t bitD, void* srcBuffer, nuint srcSize)
    {
        byte lastByte = ((byte*)srcBuffer)[srcSize - 1];
        // difference here
        var v = lastByte != 0 ? 8 - (uint)BitOperations.Log2(lastByte) : 0;
        bitD.bitsConsumed = v;
        
        return 0;
    }
    
    private static nuint M1(byte *ip, byte *iend) {
        BIT_DStream_t seqState_DStream = new ();
        BIT_initDStream1(ref seqState_DStream, ip, (nuint)(iend - ip));
        return seqState_DStream.bitContainer;
    }
    
    private static nuint M2(byte *ip, byte *iend) {
        BIT_DStream_t seqState_DStream = new ();
        BIT_initDStream2(ref seqState_DStream, ip, (nuint)(iend - ip));
        return seqState_DStream.bitContainer;
    }
}