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Add {Async}Enumerable.{Infinite}Sequence (#116538)
* Add Enumerable.InfiniteSequence * Make RangeIterator generic * Add {Async}Enumerable.Sequence
1 parent 33ce341 commit 960e063

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+1454
-236
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‎src/libraries/System.Linq.AsyncEnumerable/ref/System.Linq.AsyncEnumerable.csproj‎

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<Compile Include="System.Linq.AsyncEnumerable.cs" />
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</ItemGroup>
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<ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'">
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<Compile Include="SystemLinq.AsyncEnumerable.netcore.cs" />
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</ItemGroup>
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<ItemGroup Condition="'$(TargetFramework)' == '$(NetCoreAppCurrent)'">
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<ProjectReference Include="$(LibrariesProjectRoot)System.Linq/ref/System.Linq.csproj" />
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<ProjectReference Include="$(LibrariesProjectRoot)System.Runtime/ref/System.Runtime.csproj" />

‎src/libraries/System.Linq.AsyncEnumerable/ref/SystemLinq.AsyncEnumerable.netcore.cs‎

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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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// ------------------------------------------------------------------------------
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// Changes to this file must follow the https://aka.ms/api-review process.
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// ------------------------------------------------------------------------------
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namespace System.Linq
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{
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public static partial class AsyncEnumerable
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{
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public static System.Collections.Generic.IAsyncEnumerable<T> InfiniteSequence<T>(T start, T step) where T : System.Numerics.IAdditionOperators<T, T, T> { throw null; }
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public static System.Collections.Generic.IAsyncEnumerable<T> Sequence<T>(T start, T endInclusive, T step) where T : System.Numerics.INumber<T> { throw null; }
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}
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}

‎src/libraries/System.Linq.AsyncEnumerable/src/System.Linq.AsyncEnumerable.csproj‎

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<Project Sdk="Microsoft.NET.Sdk">
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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<TargetFrameworks>$(NetCoreAppCurrent);$(NetCoreAppPrevious);$(NetCoreAppMinimum);netstandard2.0;$(NetFrameworkMinimum)</TargetFrameworks>
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</PropertyGroup>
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<ItemGroup>
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<Compile Include="System\Linq\Shuffle.cs" />
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<Compile Include="System\Linq\SkipLast.cs" />
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<Compile Include="System\Linq\SkipWhile.cs" />
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<Compile Include="System\Linq\Append.cs" />
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<Compile Include="System\Linq\Empty.cs" />
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<Compile Include="System\Linq\MaxByAsync.cs" />
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<Compile Include="System\Linq\MinAsync.cs" />
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<Compile Include="System\Linq\Cast.cs" />
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<Compile Include="System\Linq\AsyncEnumerable.cs" />
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<Compile Include="System\Linq\TakeLast.cs" />
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<Compile Include="System\Linq\TakeWhile.cs" />
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<Compile Include="System\Linq\UnionBy.cs" />
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<Compile Include="System\Linq\AggregateAsync.cs" />
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<Compile Include="System\Linq\AnyAsync.cs" />
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<Compile Include="System\Linq\AggregateBy.cs" />
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<Compile Include="System\Linq\AllAsync.cs" />
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<Compile Include="System\Linq\Prepend.cs" />
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<Compile Include="System\Linq\AnyAsync.cs" />
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<Compile Include="System\Linq\Append.cs" />
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<Compile Include="System\Linq\AsyncEnumerable.cs" />
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<Compile Include="System\Linq\AverageAsync.cs" />
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<Compile Include="System\Linq\Cast.cs" />
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<Compile Include="System\Linq\Chunk.cs" />
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<Compile Include="System\Linq\Concat.cs" />
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<Compile Include="System\Linq\ContainsAsync.cs" />
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<Compile Include="System\Linq\AggregateBy.cs" />
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<Compile Include="System\Linq\CountBy.cs" />
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<Compile Include="System\Linq\CountAsync.cs" />
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<Compile Include="System\Linq\CountBy.cs" />
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<Compile Include="System\Linq\DefaultIfEmpty.cs" />
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<Compile Include="System\Linq\DistinctBy.cs" />
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<Compile Include="System\Linq\Distinct.cs" />
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<Compile Include="System\Linq\DistinctBy.cs" />
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<Compile Include="System\Linq\ElementAtAsync.cs" />
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<Compile Include="System\Linq\ToAsyncEnumerable.cs" />
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<Compile Include="System\Linq\ExceptBy.cs" />
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<Compile Include="System\Linq\Empty.cs" />
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<Compile Include="System\Linq\Except.cs" />
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<Compile Include="System\Linq\ExceptBy.cs" />
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<Compile Include="System\Linq\FirstAsync.cs" />
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<Compile Include="System\Linq\GroupBy.cs" />
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<Compile Include="System\Linq\GroupJoin.cs" />
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<Compile Include="System\Linq\Index.cs" />
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<Compile Include="System\Linq\IntersectBy.cs" />
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<Compile Include="System\Linq\Intersect.cs" />
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<Compile Include="System\Linq\IntersectBy.cs" />
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<Compile Include="System\Linq\Join.cs" />
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<Compile Include="System\Linq\LastAsync.cs" />
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<Compile Include="System\Linq\LeftJoin.cs" />
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<Compile Include="System\Linq\ToArrayAsync.cs" />
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<Compile Include="System\Linq\ToDictionaryAsync.cs" />
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<Compile Include="System\Linq\ToListAsync.cs" />
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<Compile Include="System\Linq\ToLookupAsync.cs" />
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<Compile Include="System\Linq\MaxAsync.cs" />
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<Compile Include="System\Linq\MaxByAsync.cs" />
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<Compile Include="System\Linq\MinAsync.cs" />
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<Compile Include="System\Linq\MinByAsync.cs" />
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<Compile Include="System\Linq\OfType.cs" />
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<Compile Include="System\Linq\OrderBy.cs" />
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<Compile Include="System\Linq\Prepend.cs" />
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<Compile Include="System\Linq\Range.cs" />
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<Compile Include="System\Linq\Repeat.cs" />
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<Compile Include="System\Linq\Reverse.cs" />
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<Compile Include="System\Linq\RightJoin.cs" />
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<Compile Include="System\Linq\Select.cs" />
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<Compile Include="System\Linq\SelectMany.cs" />
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<Compile Include="System\Linq\SequenceEqualAsync.cs" />
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<Compile Include="System\Linq\Shuffle.cs" />
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<Compile Include="System\Linq\SingleAsync.cs" />
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<Compile Include="System\Linq\Skip.cs" />
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<Compile Include="System\Linq\SkipLast.cs" />
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<Compile Include="System\Linq\SkipWhile.cs" />
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<Compile Include="System\Linq\SumAsync.cs" />
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<Compile Include="System\Linq\Take.cs" />
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<Compile Include="System\Linq\TakeLast.cs" />
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<Compile Include="System\Linq\TakeWhile.cs" />
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<Compile Include="System\Linq\ThrowHelper.cs" />
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<Compile Include="System\Linq\ToArrayAsync.cs" />
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<Compile Include="System\Linq\ToAsyncEnumerable.cs" />
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<Compile Include="System\Linq\ToDictionaryAsync.cs" />
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<Compile Include="System\Linq\ToHashSetAsync.cs" />
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<Compile Include="System\Linq\ToListAsync.cs" />
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<Compile Include="System\Linq\ToLookupAsync.cs" />
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<Compile Include="System\Linq\Union.cs" />
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<Compile Include="System\Linq\UnionBy.cs" />
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<Compile Include="System\Linq\Where.cs" />
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<Compile Include="System\Linq\Zip.cs" />
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</ItemGroup>
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<ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'">
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<Compile Include="System\Linq\InfiniteSequence.cs" />
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<Compile Include="System\Linq\Sequence.cs" />
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</ItemGroup>
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<ItemGroup Condition="'$(TargetFramework)' == '$(NetCoreAppCurrent)'">
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<Reference Include="System.Collections" />
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<Reference Include="System.Linq" />

‎src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/InfiniteSequence.cs‎

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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using System.Collections.Generic;
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using System.Diagnostics;
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using System.Numerics;
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using System.Runtime.CompilerServices;
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using System.Runtime.InteropServices;
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namespace System.Linq
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{
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public static partial class AsyncEnumerable
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{
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/// <summary>Generates an infinite sequence that begins with <paramref name="start"/> and yields additional values each incremented by <paramref name="step"/>.</summary>
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/// <typeparam name="T">The type of the value to be yielded in the result sequence.</typeparam>
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/// <param name="start">The starting value.</param>
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/// <param name="step">The amount by which the next yielded value should be incremented from the previous yielded value.</param>
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/// <returns>An <see cref="IAsyncEnumerable{T}"/> that contains the sequence.</returns>
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public static IAsyncEnumerable<T> InfiniteSequence<T>(T start, T step) where T : IAdditionOperators<T, T, T>
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{
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if (start is null)
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{
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ThrowHelper.ThrowArgumentNullException(nameof(start));
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}
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if (step is null)
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{
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ThrowHelper.ThrowArgumentNullException(nameof(step));
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}
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return Iterator(start, step);
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static async IAsyncEnumerable<T> Iterator(T start, T step)
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{
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while (true)
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{
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yield return start;
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start += step;
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}
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}
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}
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}
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}

‎src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/Sequence.cs‎

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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using System.Collections.Generic;
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using System.Diagnostics;
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using System.Numerics;
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using System.Runtime.CompilerServices;
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using System.Runtime.InteropServices;
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namespace System.Linq
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{
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public static partial class AsyncEnumerable
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{
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/// <summary>Generates a sequence that begins with <paramref name="start"/> and yields additional values each incremented by <paramref name="step"/> until <paramref name="endInclusive"/> is reached.</summary>
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/// <typeparam name="T">The type of the value to be yielded in the result sequence.</typeparam>
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/// <param name="start">The starting value. This value will always be included in the resulting sequence.</param>
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/// <param name="endInclusive">The ending bound beyond which values will not be included in the sequence.</param>
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/// <param name="step">The amount by which the next value in the sequence should be incremented from the previous value.</param>
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/// <returns>An <see cref="IAsyncEnumerable{T}"/> that contains the sequence.</returns>
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/// <exception cref="ArgumentNullException"><paramref name="start"/> is <see langword="null"/>.</exception>
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/// <exception cref="ArgumentNullException"><paramref name="step"/> is <see langword="null"/>.</exception>
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/// <exception cref="ArgumentNullException"><paramref name="endInclusive"/> is <see langword="null"/>.</exception>
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/// <exception cref="ArgumentOutOfRangeException"><paramref name="step"/> is greater than zero but <paramref name="endInclusive"/> is less than <paramref name="start"/>.</exception>
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/// <exception cref="ArgumentOutOfRangeException"><paramref name="step"/> is less than zero but <paramref name="endInclusive"/> is greater than <paramref name="start"/>.</exception>
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/// <exception cref="ArgumentOutOfRangeException"><paramref name="step"/> is zero and <paramref name="endInclusive"/> does not equal <paramref name="start"/>.</exception>
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public static IAsyncEnumerable<T> Sequence<T>(T start, T endInclusive, T step) where T : INumber<T>
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{
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if (start is null)
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{
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ThrowHelper.ThrowArgumentNullException(nameof(start));
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}
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if (endInclusive is null)
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{
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ThrowHelper.ThrowArgumentNullException(nameof(endInclusive));
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}
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if (step is null)
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{
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ThrowHelper.ThrowArgumentNullException(nameof(step));
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}
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if (step > T.Zero)
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{
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// Presumed to be the most common case, step > 0. Validate that endInclusive >= start, as otherwise we can't easily
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// guarantee that the sequence will terminate.
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if (endInclusive < start)
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{
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ThrowHelper.ThrowArgumentOutOfRangeException(nameof(endInclusive));
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}
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// Otherwise, just produce an incrementing sequence.
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return IncrementingIterator(start, endInclusive, step);
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}
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else if (step < T.Zero)
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{
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// step < 0. Validate that endInclusive <= start, as otherwise we can't easily guarantee that the sequence will terminate.
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if (endInclusive > start)
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{
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ThrowHelper.ThrowArgumentOutOfRangeException(nameof(endInclusive));
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}
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// Then produce the decrementing sequence.
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return DecrementingIterator(start, endInclusive, step);
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}
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else
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{
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// step == 0. If start != endInclusive, then the sequence would be infinite. As such, we validate
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// that they're equal, and if they are, we return a sequence that yields the start/endInclusive value once.
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if (start != endInclusive)
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{
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ThrowHelper.ThrowArgumentOutOfRangeException(nameof(step));
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}
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return Repeat(start, 1);
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}
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static async IAsyncEnumerable<T> IncrementingIterator(T start, T endInclusive, T step)
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{
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Debug.Assert(step > T.Zero);
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yield return start;
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while (true)
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{
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T next = start + step;
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if (next >= endInclusive || next <= start)
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{
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if (next == endInclusive && start != next)
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{
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yield return next;
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}
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yield break;
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}
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yield return next;
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start = next;
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}
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}
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static async IAsyncEnumerable<T> DecrementingIterator(T start, T endInclusive, T step)
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{
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Debug.Assert(step < T.Zero);
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yield return start;
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while (true)
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{
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T next = start + step;
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if (next <= endInclusive || next >= start)
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{
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if (next == endInclusive && start != next)
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{
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yield return next;
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}
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yield break;
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}
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yield return next;
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start = next;
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}
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}
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}
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}
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}

‎src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/ThrowHelper.cs‎

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}
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}
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[DoesNotReturn]
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internal static void ThrowArgumentNullException(string paramName) => throw new ArgumentNullException(paramName);
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[DoesNotReturn]
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internal static void ThrowArgumentOutOfRangeException(string paramName) => throw new ArgumentOutOfRangeException(paramName);
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