using System;

​

public class MurmurHash2

{

    public static uint Hash(byte[] data, uint seed = 0)

    {

        const uint m = 0x5bd1e995;

        const int r = 24;

        int length = data.Length;

        uint h = seed ^ (uint)length;

        int i = 0;

        while (length >= 4)

        {

            uint k = BitConverter.ToUInt32(data, i);

​

            k *= m;

            k ^= k >> r;

            k *= m;

​

            h *= m;

            h ^= k;

​

            i += 4;

            length -= 4;

        }

        switch (length)

        { 

            case 3:

                h ^= (uint)(data[i + 2] << 16);

                goto case 2;

            case 2:

                h ^= (uint)(data[i + 1] << 8);

                goto case 1;

            case 1:

                h ^= data[i];

                h *= m;

                break;

        }

        h ^= h >> 13;

        h *= m;

        h ^= h >> 15;

​

        return h;

    }

    public static void Main(string[] args)

    {

        const UInt64 product1 = 1;

        const UInt64 customer1 = 1;

        var bytesProduct1 = BitConverter.GetBytes(product1);

        UInt64 hashProduct1 = Hash(bytesProduct1);

        var combinedProduct1Customer1 = (hashProduct1 ^ customer1);

        var bytesCombinedProduct1Customer1 = BitConverter.GetBytes(combinedProduct1Customer1);      

        UInt64 hashCombinedProduct1Customer1 = Hash(bytesCombinedProduct1Customer1);

        Console.WriteLine($"Hash value: {hashProduct1}, {hashCombinedProduct1Customer1}");

    }

}

​