using System;

using System.Text;

using System.Diagnostics;

public class Program

{

    public static void Main()

    {

        ReadOnlySpan<byte> r = stackalloc byte[] { 52, 48, 48, 55, 48 };

        var sw = new Stopwatch();

        int result = 0;

        string sresult = string.Empty;

        sw.Start();

        for (int i=0; i<10000000; i++) sresult = Test0(r);

        sw.Stop();

        Console.WriteLine($"Test0 took {sw.ElapsedMilliseconds}ms {sresult}");

​

        sw.Restart();

        for (int i=0; i<10000000; i++) result = Test1 (r);

        sw.Stop();

        Console.WriteLine($"Test1 took {sw.ElapsedMilliseconds}ms {result}");

​

        sw.Restart();

        for (int i=0; i<10000000; i++) result =  Test2(r);

        sw.Stop();

        Console.WriteLine($"Test2 took {sw.ElapsedMilliseconds}ms {result}");

​

        sw.Restart();

        for (int i=0; i<10000000; i++) result = Test3(r);

        sw.Stop();

        Console.WriteLine($"Test3 took {sw.ElapsedMilliseconds}ms {result}");

​

        sw.Restart();

        for (int i=0; i<10000000; i++) result = Test4(r);

        sw.Stop();

        Console.WriteLine($"Test4 took {sw.ElapsedMilliseconds}ms {result}");

​

        sw.Restart();

        for (int i=0; i<10000000; i++) result = Test5(r);

        sw.Stop();

        Console.WriteLine($"Test5 took {sw.ElapsedMilliseconds}ms {result}");

​

​

        sw.Restart();

        for (int i=0; i<10000000; i++) result = Test6(r);

        sw.Stop();

        Console.WriteLine($"Test6 took {sw.ElapsedMilliseconds}ms {sresult}");

​

    }

​

    public static string Test0(ReadOnlySpan<byte> r)

    {

        string s = Encoding.ASCII.GetString(r);

        return(s); 

    }

    public static int Test1(ReadOnlySpan<byte> r)

    {

        string s = Encoding.ASCII.GetString(r);

        return(int.Parse(s)); 

    }

​

    public static int Test2(ReadOnlySpan<byte> data)

    {

        if (System.Buffers.Text.Utf8Parser.TryParse(data, out int value, out int bytes))

        {

            return(value);

        }   

        else

            return(0);

    }

    public static int Test3(ReadOnlySpan<byte> span)

    {

        Span<char> chars = stackalloc char[span.Length];

        Encoding.ASCII.GetChars(span, chars);

        return(int.Parse(chars)); 

    }

​

    public static int Test4(ReadOnlySpan<byte> span)

    {

        Span<char> chars = stackalloc char[span.Length];

        Encoding.ASCII.GetChars(span, chars);

        return(0); 

    }

​

    public static int Test5(ReadOnlySpan<byte> source)

    {

        int answer = 0;

        int index = 0;

        int c = source[index];

        answer = c - '0';

        while (true)

        {

            index++;

            if ((uint)index >= (uint)source.Length)

                break;

            c = source[index];

            answer = answer * 10 + c - '0';

        }

         return answer;

    }

​

    public static int Test6(ReadOnlySpan<byte> span)

    {

        int number = 0;

        foreach (byte digit in span)

        {

            if (digit < 48 || digit > 57) // Make sure the byte is a valid ASCII digit (0-9)

            {

                throw new ArgumentException("Invalid digit in span.");

            }

            number = number * 10 + (digit - 48); // Convert the digit from ASCII to integer

        }

        return number;

    }

}