regexbench.cs

regexbench.cs

public partial class Bench
{
	private const int Rep = 10_000_000;

	private readonly Regex _regex = MyRegex();
	private readonly string _input = "723402139283478235u7uA874-sdjw4##7fshsjs6763820XSDFww+___43333hnd";
	private int _pos = 0;

	[Benchmark(Baseline = true)]
	public int Test1()
	{
		var sum = 0;
		for (int i = 0; i < Rep; i++)
		{
			var m = _regex.Match(_input, _pos);
			sum += m.Length;
		}

		return sum;
	}

	[Benchmark]
	public int Test2()
	{
		var sum = 0;
		for (int i = 0; i < Rep; i++)
		{
			_pos = 0;
			var start = _pos;
			ReadOnlySpan<char> input = _input;
			if (input[_pos] == '0')
			{
				sum += 1;
				continue;
			}

			while (_pos < input.Length && input[_pos] >= '0' && input[_pos] <= '9')
			{
				_pos++;
			}

			sum += _pos - start;
		}

		return sum;
	}

    [GeneratedRegex(@"^0|([1-9][0-9]*)")]
    private static partial Regex MyRegex();
}