// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

namespace Tester;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Configs;

[SimpleJob(iterationCount: 100)]
public class Test {
  [Params(20)]
  public int len;
  public int[] source;
  [GlobalSetup]
  public void Setup() {
    source = new int[len];
    for (var i = 0; i < len; i++) {
      source[i] = i;
    }
  }
  [Benchmark]
  public int[] GetOddByGeneral() {
    var result = new int[len];
    int _len = 0;
    for (var i = 0; i < len; i++) {
      if (source[i] % 2 == 1) {
        result[i] = source[i];
        _len++;
      }
    }
    return result[0.._len];
  }
  [Benchmark]
  public int[] GetOddBySpan() {
    Span<int> sourceSpan = stackalloc int[len];
    int _len = 0;
    for (var i = 0; i < len; i++) {
      if (source[i] % 2 == 1) {
        sourceSpan[i] = source[i];
        _len++;
      }
    }
    return sourceSpan.Slice(0, _len).ToArray();
  }

}


public class Program {
  static void Main(string[] args) {
    var summary = BenchmarkDotNet.Running.BenchmarkRunner.Run<Test>(
      BenchmarkDotNet.Configs.DefaultConfig.Instance
      .WithSummaryStyle(BenchmarkDotNet.Reports.SummaryStyle.Default.WithMaxParameterColumnWidth(100))
    );
    Console.WriteLine(summary);
  }
}