indexOfAnyBench.cs

using BenchmarkDotNet.Attributes;
using System;
using System.Linq;
using System.Buffers;
using System.Text;
using MicroBenchmarks;

namespace StringSearcher;

[BenchmarkCategory(Categories.Libraries)]
public class IndexOfAnyBenchmarks
{
    private byte[] _targets = null!;
    private byte[] _byteBuffer = null!;

    [Params(1024)]
    public int length;

    [GlobalSetup]
    public void Setup()
    {
        var rnd = new Random(42);

        byte[] a = new byte[length];
        int expectedIndex = length / 2;
        for (int i = 0; i < length; i++)
        {
            if (i == expectedIndex)
            {
                continue;
            }
            a[i] = 255;
        }
        _byteBuffer = a;

        _targets = new byte[length * 2];
        for (int i = 0; i < _targets.Length; i++)
        {
            if (i == length + 1)
            {
                continue;
            }
            _targets[i] = (byte)rnd.Next(1, 255);
        }
    }

    public ReadOnlySpan<byte> values => _targets;
    public Span<byte> span => new Span<byte>(_byteBuffer);
    [Benchmark] public int MyBench() => LastIndexOfAny(span, values);

    private static int LastIndexOfAny(Span<byte> span, ReadOnlySpan<byte> values)
    {
        return span.LastIndexOfAny(SearchValues.Create(values));
    }
}