用于处理大量数字的库 c#

我真的很想制作自己的库来处理大量数据。我开始做。我意识到我不知道该怎么做。

public struct BigInt
{
    private byte[] Value { get; set; }

    public BigInt(string value)
    {
        if (value.Length != 0)
            Value = new byte[value.Length];
        else
        {
            Value = null;
            return;
        }
        for (int i = value.Length - 1; i >= 0; i--)
            Value[i] = (byte)value[i];
    }

    public BigInt(byte[] value) { this.Value = value; }

    public override string ToString() => Encoding.Default.GetString(Value);

    public static implicit operator BigInt(string num) => new BigInt(num);

    public static implicit operator string(BigInt num) => Encoding.Default.GetString(num.Value);

    public static string operator +(BigInt c1, BigInt c2) => Addition(c1.Value, c2.Value);

    public static string operator +(BigInt c1, string c2) => Addition(c1.Value, Encoding.Default.GetBytes(c2));

    public static string operator *(BigInt c1, BigInt c2) => Multiplication(c1.Value, c2.Value);

    public static string operator *(BigInt c1, string c2) => Multiplication(c1.Value, Encoding.Default.GetBytes(c2));

    public static string Addition(byte[] x, byte[] y)
    {
        List<byte> result = new List<byte>();
        int c = 0, d = 0;
        List<byte> z = new List<byte>();
        if(x.Length > y.Length)
        {
            z.InsertRange(0, Encoding.Default.GetBytes(new String('0', x.Length - y.Length).ToCharArray()));
            z.AddRange(y);
            y = z.ToArray();
        }
        else
        {
            z.InsertRange(0, Encoding.Default.GetBytes(new String('0', y.Length - x.Length).ToCharArray()));
            z.AddRange(x);
            x = z.ToArray();
        }
        for(int i = x.Length-1; i>=0; i--)
        {
            byte a = x[i];
            byte b = y[i];
            c = (d + (a % 48) + (b % 48)) % 10;
            result.Add((byte)c);
            d = (d + a % 48 + b % 48) / 10;
        }
        if (d != 0)
            result.Add((byte)d);
        result.Reverse();
        return string.Join("", result);
    }

    public static string Multiplication(byte[] x, byte[] y)
    {
        List<byte>[] result = new List<byte>[y.Length];
        for (int i = 0; i < y.Length; i++)
        {
            int c = 0;
            int d = 0;
            List<byte> array = new List<byte>();
            for (int j = 0; j < x.Length; j++)
            {
                byte a = x[x.Length - 1 - j];
                byte b = y[y.Length - 1 - i];
                c = (d + (a % 48) * (b % 48)) % 10;
                array.Add((byte)c);
                d = (d + (a % 48) * (b % 48)) / 10;
            }
            if (d > 0)
                array.Add((byte)d);
            result[i] = array;
        }

        for (int i = 0; i < result.Length; i++)
            for (int j = 0; j < result[i].Count / 2; j++)
            {
                byte temp = result[i][j];
                result[i][j] = result[i][result[i].Count - 1 - j];
                result[i][result[i].Count - 1 - j] = temp;
            }

        if (result.Length > 1)
            for (int i = 1; i < result.Length; i++)
                for (int j = 0; j < result.Length - i; j++)
                    result[j + i].Add((byte)0);

        if (result.Length > 1)
        {
            for (int i = 0; i < result.Length - 1; i++)
            {
                List<byte> z = result[0];
                for (int j = 0; j < z.Count; j++)
                    z[j] += 48;
                result[0] = new List<byte>(Encoding.Default.GetBytes(Addition(z.ToArray(), result[i + 1].ToArray())));
            }
            return Encoding.Default.GetString(result[0].ToArray());
        }
        return String.Join("", result[0]);
    }

    public static string Pow(string x, int degrees)
    {
        if (degrees == 0) return "1";
        if (degrees == 1) return x;
        byte[] result = Encoding.Default.GetBytes(x);
        byte[] num = result;
        for (int i = 2; i <= degrees; i++)
            result = Encoding.Default.GetBytes(Multiplication(result, num));
        return Encoding.Default.GetString(result);
    }

    public static string Factorial(int number)
    {
        if (number == 0) return "1";
        if (number <= 2) return number.ToString();
        byte[] result = Encoding.Default.GetBytes((6).ToString());
        for (int i = 4; i <= number; i++)
            result = Encoding.Default.GetBytes(Multiplication(result, Encoding.Default.GetBytes(i.ToString())));
        return Encoding.Default.GetString(result);
    }
}

以上是我想出的所有代码。而且我确信这段代码是尽可能糟糕的。

我想知道在编写这样的库时要遵循什么。（例如，将数据存储在哪里以便它需要更少的内存或使用什么算法来提高工作速度）更多的例子是可取的。（任何语言都可以）嗯，一些文学作品，这样你以后就不必问问题了。