// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

using BenchmarkDotNet.Attributes;
using SixLabors.ImageSharp.Memory;
using SixLabors.ImageSharp.PixelFormats;

namespace SixLabors.ImageSharp.Benchmarks.General;

public class Buffer2D_DangerousGetRowSpan
{
    private const int Height = 1024;

    [Params(0.5, 2.0, 10.0)]
    public double SizeMegaBytes { get; set; }

    private Buffer2D<Rgba32> buffer;

    [GlobalSetup]
    public unsafe void Setup()
    {
        int totalElements = (int)(1024 * 1024 * this.SizeMegaBytes) / sizeof(Rgba32);

        int width = totalElements / Height;
        MemoryAllocator allocator = Configuration.Default.MemoryAllocator;
        this.buffer = allocator.Allocate2D<Rgba32>(width, Height);
    }

    [GlobalCleanup]
    public void Cleanup() => this.buffer.Dispose();

    [Benchmark]
    public int DangerousGetRowSpan() =>
        this.buffer.DangerousGetRowSpan(1).Length +
        this.buffer.DangerousGetRowSpan(Height - 1).Length;

    // BenchmarkDotNet=v0.13.0, OS=Windows 10.0.19044
    // Intel Core i9-10900X CPU 3.70GHz, 1 CPU, 20 logical and 10 physical cores
    //
    // |              Method | SizeMegaBytes |      Mean |     Error |    StdDev |
    // |-------------------- |-------------- |----------:|----------:|----------:|
    // | DangerousGetRowSpan |           0.5 |  7.498 ns | 0.1784 ns | 0.3394 ns |
    // | DangerousGetRowSpan |             2 |  6.542 ns | 0.1565 ns | 0.3659 ns |
    // | DangerousGetRowSpan |            10 | 38.556 ns | 0.6604 ns | 0.8587 ns |
}