// @nuget: BenchmarkDotNet -Version 0.13.2

using System;

using System.Linq;

using System.Text;

using System.Collections.Generic;

using BenchmarkDotNet.Running;

using BenchmarkDotNet.Attributes;

using BenchmarkDotNet.Jobs;

using BenchmarkDotNet.Configs;

using BenchmarkDotNet.Toolchains.InProcess.Emit;

using Perfolizer.Horology;

using BenchmarkDotNet.Loggers;

using System.Text.RegularExpressions;

​

[assembly: System.Diagnostics.Debuggable(isJITTrackingEnabled: false, isJITOptimizerDisabled: false)]

BenchmarkRunner.Run<ComparisonBenchmarkTests>(DefaultConfig.Instance.AddJob(Job.Default.WithToolchain(new InProcessEmitToolchain(timeout: TimeSpan.FromSeconds(9), logOutput: false)).WithLaunchCount(1).WithWarmupCount(5).WithIterationCount(20).WithIterationTime(TimeInterval.FromMilliseconds(80))).AddLogger(new ConsoleLogger(unicodeSupport: true, ConsoleLogger.CreateGrayScheme())).WithOptions(ConfigOptions.DisableLogFile));

[MemoryDiagnoser]

public class ComparisonBenchmarkTests

{

    private void Do()

    {

    }

​

    [Params("DE12500123456789012345")]

    public string Iban { get; set; }

​

    [Benchmark]

    public void RegexConcat()

    {

        var groupRegex = new Regex(@"^([A-Z]{2})(?<Ast>\d{5})(\d{5})(?<Ast>.*)(\d{3})$");

        var x = groupRegex.ReplaceGroup(Iban, "Ast", '*');

    }

​

    [Benchmark]

    public void PureConcat()

    {

        var masked = $"{Iban[0..2]}{"".PadRight(5, '*')}{Iban[7..12]}{"".PadRight(Iban.Length - 15, '*')}{Iban[^3..]}";

    }

    [Benchmark]

    public void PureRegex()

    {

        var masked = Regex.Replace(Iban, @"(?<=^[A-Z]{2}(?:\d{0,4}|\d{10,}(?=\d{4,}$)))\d", "*");

    }

}

​

public static class X

{

    public static string ReplaceGroup(this Regex regex, string input, string groupName, char pattern)

    {

        return regex.Replace(input, m =>

        {

            var group = m.Groups[groupName];

            var sb = new StringBuilder();

            var previousCaptureEnd = 0;

            foreach (var capture in group.Captures.Cast<Capture>())

            {

                var currentCaptureEnd = capture.Index + capture.Length - m.Index;

                var currentCaptureLength = capture.Index - m.Index - previousCaptureEnd;

                sb.Append(m.Value.Substring(previousCaptureEnd, currentCaptureLength));

                sb.Append("".PadRight(currentCaptureLength, pattern));

                previousCaptureEnd = currentCaptureEnd;

            }

​

            sb.Append(m.Value.Substring(previousCaptureEnd));

            return sb.ToString();

        });

    }

}