DTLib.XXHash/src/Standart.Hash.xxHash/__inline__xxHash32.cs

/*
* This is the auto generated code.
* All function calls are inlined in XXH32
* Please don't try to analyze it.
*/

using System.Runtime.CompilerServices;

namespace Standart.Hash.xxHash;

public partial class xxHash32
{
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    private static unsafe uint __inline__XXH32(byte* input, int len, uint seed)
    {
        uint h32;

        if (len >= 16)
        {
            byte* end = input + len;
            byte* limit = end - 15;

            uint v1 = seed + XXH_PRIME32_1 + XXH_PRIME32_2;
            uint v2 = seed + XXH_PRIME32_2;
            uint v3 = seed + 0;
            uint v4 = seed - XXH_PRIME32_1;

            do
            {
                var reg1 = *((uint*)(input + 0));
                var reg2 = *((uint*)(input + 4));
                var reg3 = *((uint*)(input + 8));
                var reg4 = *((uint*)(input + 12));

                // XXH32_round
                v1 += reg1 * XXH_PRIME32_2;
                v1 = (v1 << 13) | (v1 >> (32 - 13));
                v1 *= XXH_PRIME32_1;

                // XXH32_round
                v2 += reg2 * XXH_PRIME32_2;
                v2 = (v2 << 13) | (v2 >> (32 - 13));
                v2 *= XXH_PRIME32_1;

                // XXH32_round
                v3 += reg3 * XXH_PRIME32_2;
                v3 = (v3 << 13) | (v3 >> (32 - 13));
                v3 *= XXH_PRIME32_1;

                // XXH32_round
                v4 += reg4 * XXH_PRIME32_2;
                v4 = (v4 << 13) | (v4 >> (32 - 13));
                v4 *= XXH_PRIME32_1;

                input += 16;
            } while (input < limit);

            h32 = ((v1 << 1) | (v1 >> (32 - 1))) +
                  ((v2 << 7) | (v2 >> (32 - 7))) +
                  ((v3 << 12) | (v3 >> (32 - 12))) +
                  ((v4 << 18) | (v4 >> (32 - 18)));
        }
        else
        {
            h32 = seed + XXH_PRIME32_5;
        }

        h32 += (uint) len;

        // XXH32_finalize
        len &= 15;
        while (len >= 4)
        {
            h32 += *((uint*) input) * XXH_PRIME32_3;
            input += 4;
            h32 = ((h32 << 17) | (h32 >> (32 - 17))) * XXH_PRIME32_4;
            len -= 4;
        }

        while (len > 0)
        {
            h32 += *((byte*) input) * XXH_PRIME32_5;
            ++input;
            h32 = ((h32 << 11) | (h32 >> (32 - 11))) * XXH_PRIME32_1;
            --len;
        }

        // XXH32_avalanche
        h32 ^= h32 >> 15;
        h32 *= XXH_PRIME32_2;
        h32 ^= h32 >> 13;
        h32 *= XXH_PRIME32_3;
        h32 ^= h32 >> 16;

        return h32;
    }
    
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    private static unsafe void __inline__XXH32_stream_process(byte[] input, int len, ref uint v1, ref uint v2, ref uint v3, ref uint v4)
    {
        fixed (byte* pData = &input[0])
        {
            byte* ptr = pData;
            byte* limit = ptr + len;

            do
            {
                var reg1 = *((uint*)(ptr + 0));
                var reg2 = *((uint*)(ptr + 4));
                var reg3 = *((uint*)(ptr + 8));
                var reg4 = *((uint*)(ptr + 12));

                // XXH32_round
                v1 += reg1 * XXH_PRIME32_2;
                v1 = (v1 << 13) | (v1 >> (32 - 13));
                v1 *= XXH_PRIME32_1;

                // XXH32_round
                v2 += reg2 * XXH_PRIME32_2;
                v2 = (v2 << 13) | (v2 >> (32 - 13));
                v2 *= XXH_PRIME32_1;

                // XXH32_round
                v3 += reg3 * XXH_PRIME32_2;
                v3 = (v3 << 13) | (v3 >> (32 - 13));
                v3 *= XXH_PRIME32_1;

                // XXH32_round
                v4 += reg4 * XXH_PRIME32_2;
                v4 = (v4 << 13) | (v4 >> (32 - 13));
                v4 *= XXH_PRIME32_1;

                ptr += 16;

            } while (ptr < limit);
        }
    }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    private static unsafe uint __inline__XXH32_stream_finalize(byte[] input, int len, ref uint v1, ref uint v2, ref uint v3, ref uint v4, long length, uint seed)
    {
        fixed (byte* pData = &input[0])
        {
            byte* ptr = pData;
            uint h32;

            if (length >= 16)
            {
                h32 = ((v1 << 1) | (v1 >> (32 - 1))) +  
                      ((v2 << 7) | (v2 >> (32 - 7))) +
                      ((v3 << 12) | (v3 >> (32 - 12))) +
                      ((v4 << 18) | (v4 >> (32 - 18)));
            }
            else
            {
                h32 = seed + XXH_PRIME32_5;
            }

            h32 += (uint)length;

            // XXH32_finalize
            len &= 15;
            while (len >= 4)
            {
                h32 += *((uint*)ptr) * XXH_PRIME32_3;
                ptr += 4;
                h32 = ((h32 << 17) | (h32 >> (32 - 17))) * XXH_PRIME32_4;
                len -= 4;
            }

            while (len > 0)
            {
                h32 += *((byte*)ptr) * XXH_PRIME32_5;
                ptr++;
                h32 = ((h32 << 11) | (h32 >> (32 - 11))) * XXH_PRIME32_1;
                len--;
            }

            // XXH32_avalanche
            h32 ^= h32 >> 15;
            h32 *= XXH_PRIME32_2;
            h32 ^= h32 >> 13;
            h32 *= XXH_PRIME32_3;
            h32 ^= h32 >> 16;

            return h32;
        }
    }
}