UInt128 and UInt256 data types in c# to compare string hashes with one and another.

faketypes.cs

using System;
using System.Globalization;
using System.Text.RegularExpressions;

namespace FakeTypes
{
    // All types within this namespace are considered fakes. A UInt128 is a struct
    // containing two ulongs, their primary reason for existence is for quick calculation
    // and comparisons of hash strings as numbers. Allocation should be on the stack.

    public struct UInt128
    {
        public readonly ulong lp;
        public readonly ulong tp;

        public UInt128(string HexString)
        {
            if (HexString == null || HexString.Length != 32 || !new Regex("^[0-9a-fA-F]+$", RegexOptions.IgnoreCase).Match(HexString).Success)
                throw new Exception("Invalid hex string given. Expects length to be 32.");

            lp = UInt64.Parse(HexString.Substring(0, HexString.Length / 2), NumberStyles.HexNumber);
            tp = UInt64.Parse(HexString.Substring(HexString.Length / 2), NumberStyles.HexNumber);
        }

        public static bool operator ==(UInt128 left, UInt128 right)
        {
            return left.lp == right.lp && left.tp == right.tp;
        }

        public static bool operator !=(UInt128 left, UInt128 right)
        {
            return left.lp != right.lp && left.tp != right.tp;
        }

        public static bool operator >(UInt128 left, UInt128 right)
        {
            return left.lp > right.lp
                || (left.lp == right.lp && left.tp > right.tp);
        }

        public static bool operator <(UInt128 left, UInt128 right)
        {
            return left.lp < right.lp
                || (left.lp == right.lp && left.tp < right.tp);
        }

        public static bool operator >=(UInt128 left, UInt128 right)
        {
            return (left > right) || left == right;
        }

        public static bool operator <=(UInt128 left, UInt128 right)
        {
            return (left < right) || left == right;
        }

        public override bool Equals(object obj)
        {
            return obj != null && obj is UInt128 && (UInt128)obj == this;
        }

        public override int GetHashCode()
        {
            return (int)(lp + tp);
        }
    }

    public struct UInt256
    {
        public readonly UInt128 lp;
        public readonly UInt128 tp;

        public UInt256(string HexString)
        {
            try
            {
                lp = new UInt128(HexString.Substring(0, HexString.Length / 2));
                tp = new UInt128(HexString.Substring(HexString.Length / 2));
            }
            catch
            {
                throw new Exception("Invalid hex string given. Expects length to be 64.");
            }
        }

        public static bool operator ==(UInt256 left, UInt256 right)
        {
            return left.lp == right.lp && left.tp == right.tp;
        }

        public static bool operator !=(UInt256 left, UInt256 right)
        {
            return left.lp != right.lp && left.tp != right.tp;
        }

        public static bool operator >(UInt256 left, UInt256 right)
        {
            return left.lp > right.lp
                || (left.lp == right.lp && left.tp > right.tp);
        }

        public static bool operator <(UInt256 left, UInt256 right)
        {
            return left.lp < right.lp
                || (left.lp == right.lp && left.tp < right.tp);
        }

        public static bool operator >=(UInt256 left, UInt256 right)
        {
            return (left > right) || left == right;
        }

        public static bool operator <=(UInt256 left, UInt256 right)
        {
            return (left < right) || left == right;
        }

        public override bool Equals(object obj)
        {
            return obj != null && obj is UInt256 && (UInt256)obj == this;
        }

        public override int GetHashCode()
        {
            return lp.GetHashCode() + tp.GetHashCode();
        }
    }
    
    public static class Hash
    {
        private static readonly Dictionary<char, int> Hex2Dec = new Dictionary<char, int> {
            { '0', 0 },
            { '1', 1 },
            { '2', 2 },
            { '3', 3 },
            { '4', 4 },
            { '5', 5 },
            { '6', 6 },
            { '7', 7 },
            { '8', 8 },
            { '9', 9 },
            { 'a', 10 },
            { 'b', 11 },
            { 'c', 12 },
            { 'd', 13 },
            { 'e', 14 },
            { 'f', 15 }
        };

        public static bool LeftSmallerThan(string s1, string s2)
        {
            for (int i = 0; i < 64; i++)
                if (Hex2Dec[s1[i]] < Hex2Dec[s2[i]])
                    return true;
            return false;
        }
    }
}

Console.WriteLine("Equals");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") < new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") > new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") <= new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") >= new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") == new UInt128("1b78179072ffe9982a485541b54e281a"));

            Console.WriteLine("");
            Console.WriteLine("Off by one in the trailing part");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") < new UInt128("1b78179072ffe9982a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") > new UInt128("1b78179072ffe9982a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") <= new UInt128("1b78179072ffe9982a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") >= new UInt128("1b78179072ffe9982a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") == new UInt128("1b78179072ffe9982a485541b54e2819"));

            Console.WriteLine("");
            Console.WriteLine("Reversed");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e2819") < new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e2819") > new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e2819") <= new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e2819") >= new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e2819") == new UInt128("1b78179072ffe9982a485541b54e281a"));

            Console.WriteLine("");
            Console.WriteLine("Off by one in the leading part");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") < new UInt128("1b78179072ffe9972a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") > new UInt128("1b78179072ffe9972a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") <= new UInt128("1b78179072ffe9972a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") >= new UInt128("1b78179072ffe9972a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") == new UInt128("1b78179072ffe9972a485541b54e2819"));

            Console.WriteLine("");
            Console.WriteLine("Reversed");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("1b78179072ffe9972a485541b54e281a") < new UInt128("1b78179072ffe9982a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9972a485541b54e281a") > new UInt128("1b78179072ffe9982a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9972a485541b54e281a") <= new UInt128("1b78179072ffe9982a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9972a485541b54e281a") >= new UInt128("1b78179072ffe9982a485541b54e2819"));
            Console.WriteLine(new UInt128("1b78179072ffe9972a485541b54e281a") == new UInt128("1b78179072ffe9982a485541b54e2819"));


            Console.WriteLine("");
            Console.WriteLine("Off by a lot in the trailing part");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") < new UInt128("1b78179072ffe9982a375541b54e181a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") > new UInt128("1b78179072ffe9982a375541b54e181a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") <= new UInt128("1b78179072ffe9982a375541b54e181a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") >= new UInt128("1b78179072ffe9982a375541b54e181a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") == new UInt128("1b78179072ffe9982a375541b54e181a"));

            Console.WriteLine("");
            Console.WriteLine("Reversed");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("1b78179072ffe9982a375541b54e181a") < new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a375541b54e181a") > new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a375541b54e181a") <= new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a375541b54e181a") >= new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a375541b54e181a") == new UInt128("1b78179072ffe9982a485541b54e281a"));

            Console.WriteLine("");
            Console.WriteLine("Off by a lot in the leading part");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") < new UInt128("1278179022ffe8982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") > new UInt128("1278179022ffe8982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") <= new UInt128("1278179022ffe8982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") >= new UInt128("1278179022ffe8982a485541b54e281a"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") == new UInt128("1278179022ffe8982a485541b54e281a"));

            Console.WriteLine("");
            Console.WriteLine("Reversed");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("1278179022ffe8982a485541b54e281a") < new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1278179022ffe8982a485541b54e281a") > new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1278179022ffe8982a485541b54e281a") <= new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1278179022ffe8982a485541b54e281a") >= new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("1278179022ffe8982a485541b54e281a") == new UInt128("1b78179072ffe9982a485541b54e281a"));

            Console.WriteLine("");
            Console.WriteLine("Totally different hashes");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") < new UInt128("e6262df3369552fe24a0f2a610ebb636"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") > new UInt128("e6262df3369552fe24a0f2a610ebb636"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") <= new UInt128("e6262df3369552fe24a0f2a610ebb636"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") >= new UInt128("e6262df3369552fe24a0f2a610ebb636"));
            Console.WriteLine(new UInt128("1b78179072ffe9982a485541b54e281a") == new UInt128("e6262df3369552fe24a0f2a610ebb636"));

            Console.WriteLine("");
            Console.WriteLine("Reversed");
            Console.WriteLine("");

            Console.WriteLine(new UInt128("e6262df3369552fe24a0f2a610ebb636") < new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("e6262df3369552fe24a0f2a610ebb636") > new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("e6262df3369552fe24a0f2a610ebb636") <= new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("e6262df3369552fe24a0f2a610ebb636") >= new UInt128("1b78179072ffe9982a485541b54e281a"));
            Console.WriteLine(new UInt128("e6262df3369552fe24a0f2a610ebb636") == new UInt128("1b78179072ffe9982a485541b54e281a"));


            Console.WriteLine(new UInt256("e6262df1b78179072ffe9982a485541b54e281a3369552fe24a0f2a610ebb636") > new UInt256("1b78179072ffe998e6262df3369552fe24a0f2a610ebb6362a485541b54e281a"));