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Fastest way to read a text file: retarget net10.0, add async reads, re-run benchmark
- Both projects net7.0 -> net10.0; Nullable enabled on the sample project. - BenchmarkDotNet 0.13.7 -> 0.15.8. - Test packages to current: Microsoft.NET.Test.Sdk 18.9.0, xunit 2.9.3, xunit.runner.visualstudio 4.0.0, coverlet.collector 10.0.1. This clears NU1903 (Newtonsoft.Json 9.0.1 came in transitively through the old test SDK). - Primary constructor on WaysToReadATextFileInCsharp. - UseBufferedStreamObjectWithNoFileStreamBuffer moves to the FileStreamOptions overload. FileStreamOptions.BufferSize documents "0 or 1 means that buffering should be disabled"; the five-argument FileStream constructor documents its bufferSize as greater than zero and throws on zero. Same behaviour, but the section now stands on the API whose docs state what it teaches. - Three async reads with matching benchmarks and tests: UseFileReadAllTextAsync, UseFileReadLinesAsync, UseStreamReaderReadToEndAsync. The StreamReader one is built over a FileStream with FileOptions.Asynchronous rather than the path-taking constructor, which does not set that flag and so fakes async file access on the thread pool. - Benchmark file resolved with AppContext.BaseDirectory and copied to the output directory, replacing a six-level Directory.GetParent walk tied to one layout.
1 parent a59a6f6 commit 26ce1d9

5 files changed

Lines changed: 90 additions & 21 deletions

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‎files-csharp/FastestWayToReadATextFileInCsharp/FastestWayToReadATextFileInCsharp/FastestWayToReadATextFileInCsharp.csproj‎

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<PropertyGroup>
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<OutputType>Exe</OutputType>
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<TargetFramework>net7.0</TargetFramework>
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<TargetFramework>net10.0</TargetFramework>
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<ImplicitUsings>enable</ImplicitUsings>
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<Nullable>disable</Nullable>
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<Nullable>enable</Nullable>
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</PropertyGroup>
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<ItemGroup>
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<PackageReference Include="BenchmarkDotNet" Version="0.13.7" />
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<PackageReference Include="BenchmarkDotNet" Version="0.15.8" />
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</ItemGroup>
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<ItemGroup>
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<Content Include="BenchmarkTextFile.txt">
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<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
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</Content>
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</ItemGroup>
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</Project>

‎files-csharp/FastestWayToReadATextFileInCsharp/FastestWayToReadATextFileInCsharp/WaysToReadATextFileInCsharp.cs‎

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@@ -3,14 +3,9 @@
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namespace FastestWayToReadATextFileInCsharp;
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public class WaysToReadATextFileInCsharp
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public class WaysToReadATextFileInCsharp(string sampleFilePath)
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{
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private readonly string _sampleFilePath;
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public WaysToReadATextFileInCsharp(string sampleFilePath)
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{
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_sampleFilePath = sampleFilePath;
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}
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private readonly string _sampleFilePath = sampleFilePath;
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public string UseFileReadAllLines()
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{
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{
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var stringBuilder = new StringBuilder();
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using var fileStream = new FileStream(_sampleFilePath,
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FileMode.Open,
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FileAccess.Read,
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FileShare.Read,
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0);
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using var fileStream = new FileStream(_sampleFilePath, new FileStreamOptions
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{
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Mode = FileMode.Open,
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Access = FileAccess.Read,
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Share = FileShare.Read,
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BufferSize = 0
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});
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using var bufferedStream = new BufferedStream(fileStream);
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using var streamReader = new StreamReader(bufferedStream);
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@@ -148,4 +145,34 @@ public string UseBufferedStreamObjectWithNoFileStreamBuffer()
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return stringBuilder.ToString();
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}
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public async Task<string> UseFileReadAllTextAsync()
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=> await File.ReadAllTextAsync(_sampleFilePath);
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public async Task<string> UseFileReadLinesAsync()
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{
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var stringBuilder = new StringBuilder();
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await foreach (var line in File.ReadLinesAsync(_sampleFilePath))
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{
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stringBuilder.AppendLine(line);
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}
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stringBuilder.Length -= Environment.NewLine.Length;
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return stringBuilder.ToString();
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}
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public async Task<string> UseStreamReaderReadToEndAsync()
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{
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using var fileStream = new FileStream(_sampleFilePath, new FileStreamOptions
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{
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Mode = FileMode.Open,
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Access = FileAccess.Read,
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Share = FileShare.Read,
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Options = FileOptions.Asynchronous | FileOptions.SequentialScan
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});
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using var streamReader = new StreamReader(fileStream);
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return await streamReader.ReadToEndAsync();
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}
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}

‎files-csharp/FastestWayToReadATextFileInCsharp/FastestWayToReadATextFileInCsharp/WaysToReadATextFileInCsharpBenchmark.cs‎

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@@ -10,7 +10,7 @@ namespace FastestWayToReadATextFileInCsharp;
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public class WaysToReadATextFileInCsharpBenchmark
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{
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private static readonly string SampleFilePath
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= Path.Combine(Directory.GetParent(Directory.GetCurrentDirectory()).Parent.Parent.Parent.Parent.Parent.Parent.FullName, "BenchmarkTextFile.txt");
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= Path.Combine(AppContext.BaseDirectory, "BenchmarkTextFile.txt");
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private readonly WaysToReadATextFileInCsharp _textFileReader = new(SampleFilePath);
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[Benchmark]
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public string BufferedStreamWithNoFileStreamBuffer()
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=> _textFileReader.UseBufferedStreamObjectWithNoFileStreamBuffer();
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[Benchmark]
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public async Task<string> FileReadAllTextAsync()
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=> await _textFileReader.UseFileReadAllTextAsync();
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[Benchmark]
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public async Task<string> FileReadLinesAsync()
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=> await _textFileReader.UseFileReadLinesAsync();
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[Benchmark]
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public async Task<string> StreamReaderReadToEndAsync()
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=> await _textFileReader.UseStreamReaderReadToEndAsync();
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}

‎files-csharp/FastestWayToReadATextFileInCsharp/Tests/Tests.csproj‎

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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<TargetFramework>net7.0</TargetFramework>
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<TargetFramework>net10.0</TargetFramework>
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<ImplicitUsings>enable</ImplicitUsings>
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<Nullable>enable</Nullable>
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<IsPackable>false</IsPackable>
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</PropertyGroup>
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<ItemGroup>
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<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.3.2" />
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<PackageReference Include="xunit" Version="2.4.2" />
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<PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
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<PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.9.0" />
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<PackageReference Include="xunit" Version="2.9.3" />
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<PackageReference Include="xunit.runner.visualstudio" Version="4.0.0">
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<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
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<PrivateAssets>all</PrivateAssets>
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</PackageReference>
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<PackageReference Include="coverlet.collector" Version="3.1.2">
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<PackageReference Include="coverlet.collector" Version="10.0.1">
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<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
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<PrivateAssets>all</PrivateAssets>
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</PackageReference>

‎files-csharp/FastestWayToReadATextFileInCsharp/Tests/WaysToReadATextFileInCsharpTests.cs‎

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@@ -100,6 +100,30 @@ public void WhenReadingATextFileWithBufferedStreamObjectWithFileStreamBufferDisa
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Assert.Equal(ExpectedText, result);
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}
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[Fact]
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public async Task WhenReadingATextFileWithFileReadAllTextAsync_ThenReturnsExpectedText()
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{
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var result = await _textFileReader.UseFileReadAllTextAsync();
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Assert.Equal(ExpectedText, result);
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}
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[Fact]
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public async Task WhenReadingATextFileWithFileReadLinesAsync_ThenReturnsExpectedText()
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{
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var result = await _textFileReader.UseFileReadLinesAsync();
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Assert.Equal(ExpectedText, result);
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}
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[Fact]
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public async Task WhenReadingATextFileWithStreamReaderReadToEndAsync_ThenReturnsExpectedText()
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{
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var result = await _textFileReader.UseStreamReaderReadToEndAsync();
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Assert.Equal(ExpectedText, result);
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}
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public void Dispose()
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{
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if (File.Exists(TempFilePath))

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