using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

namespace YieldVsListPerformanceComparison
{
    public class Program
    {
        static void Main(string[] args)
        {
            BenchmarkRunner.Run<PerformanceBenchmarks>();
        }
    }

    public class PerformanceBenchmarks
    {
        private const int NumberOfElements = 10000;
        private List<int> precomputedNumbers;

        [GlobalSetup]
        public void InitializeBenchmark()
        {
            precomputedNumbers = new List<int>();
            for (var index = 0; index < NumberOfElements; index++)
            {
                precomputedNumbers.Add(index);
            }
        }

        [Benchmark]
        public void SquareNumbersUsingYield()
        {
            foreach (var number in GenerateNumbersUsingYield(NumberOfElements))
            {
                var squaredNumber = number * number;
            }
        }

        [Benchmark]
        public void SquareNumbersUsingList()
        {
            foreach (var number in precomputedNumbers)
            {
                var squaredNumber = number * number;
            }
        }

        private IEnumerable<int> GenerateNumbersUsingYield(int maximumValue)
        {
            for (int index = 0; index < maximumValue; index++)
            {
                yield return index;
            }
        }
    }
}

// .NET 8
public void SquareNumbersUsingYield()
{
    IEnumerator<int> enumerator = GenerateNumbersUsingYield(10000).GetEnumerator();
    try
    {
        while (enumerator.MoveNext())
        {
            int current = enumerator.Current;
        }
    }
    finally
    {
        if (enumerator != null)
        {
            enumerator.Dispose();
        }
    }
}

// .NET 8
public void SquareNumbersUsingList()
{
    List<int>.Enumerator enumerator = precomputedNumbers.GetEnumerator();
    try
    {
        while (enumerator.MoveNext())
        {
            int current = enumerator.Current;
        }
    }
    finally
    {
        ((IDisposable)enumerator).Dispose();
    }
}

// .NET 8
.method public hidebysig 
    instance void SquareNumbersUsingYield () cil managed 
{
    .custom instance void [BenchmarkDotNet.Annotations]BenchmarkDotNet.Attributes.BenchmarkAttribute::.ctor(int32, string) = (
        01 00 28 00 00 00 01 5f 00 00
    )
    // Method begins at RVA 0x2098
    // Code size 47 (0x2f)
    .maxstack 2
    .locals init (
        [0] class [System.Runtime]System.Collections.Generic.IEnumerator`1<int32>
    )

    // sequence point: (line 43, col 36) to (line 43, col 79) in _
    IL_0000: ldarg.0
    IL_0001: ldc.i4 10000
    IL_0006: call instance class [System.Runtime]System.Collections.Generic.IEnumerable`1<int32> YieldVsListPerformanceComparison.PerformanceBenchmarks::GenerateNumbersUsingYield(int32)
    IL_000b: callvirt instance class [System.Runtime]System.Collections.Generic.IEnumerator`1<!0> class [System.Runtime]System.Collections.Generic.IEnumerable`1<int32>::GetEnumerator()
    IL_0010: stloc.0
    .try
    {
        // sequence point: hidden
        IL_0011: br.s IL_001a
        // loop start (head: IL_001a)
            // sequence point: (line 43, col 22) to (line 43, col 32) in _
            IL_0013: ldloc.0
            IL_0014: callvirt instance !0 class [System.Runtime]System.Collections.Generic.IEnumerator`1<int32>::get_Current()
            // sequence point: (line 45, col 17) to (line 45, col 53) in _
            IL_0019: pop

            // sequence point: (line 43, col 33) to (line 43, col 35) in _
            IL_001a: ldloc.0
            IL_001b: callvirt instance bool [System.Runtime]System.Collections.IEnumerator::MoveNext()
            IL_0020: brtrue.s IL_0013
        // end loop

        IL_0022: leave.s IL_002e
    }

// .NET 8
.method public hidebysig 
    instance void SquareNumbersUsingList () cil managed 
{
    .custom instance void [BenchmarkDotNet.Annotations]BenchmarkDotNet.Attributes.BenchmarkAttribute::.ctor(int32, string) = (
        01 00 31 00 00 00 01 5f 00 00
    )
    // Method begins at RVA 0x20e4
    // Code size 48 (0x30)
    .maxstack 1
    .locals init (
        [0] valuetype [System.Collections]System.Collections.Generic.List`1/Enumerator<int32>
    )

    // sequence point: (line 52, col 36) to (line 52, col 54) in _
    IL_0000: ldarg.0
    IL_0001: ldfld class [System.Collections]System.Collections.Generic.List`1<int32> YieldVsListPerformanceComparison.PerformanceBenchmarks::precomputedNumbers
    IL_0006: callvirt instance valuetype [System.Collections]System.Collections.Generic.List`1/Enumerator<!0> class [System.Collections]System.Collections.Generic.List`1<int32>::GetEnumerator()
    IL_000b: stloc.0
    .try
    {
        // sequence point: hidden
        IL_000c: br.s IL_0016
        // loop start (head: IL_0016)
            // sequence point: (line 52, col 22) to (line 52, col 32) in _
            IL_000e: ldloca.s 0
            IL_0010: call instance !0 valuetype [System.Collections]System.Collections.Generic.List`1/Enumerator<int32>::get_Current()
            // sequence point: (line 54, col 17) to (line 54, col 53) in _
            IL_0015: pop

            // sequence point: (line 52, col 33) to (line 52, col 35) in _
            IL_0016: ldloca.s 0
            IL_0018: call instance bool valuetype [System.Collections]System.Collections.Generic.List`1/Enumerator<int32>::MoveNext()
            IL_001d: brtrue.s IL_000e
        // end loop

        IL_001f: leave.s IL_002f
    }