Remove unsafe from EqualStartingCharacterCount#121102
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@EgorBot -windows_intel -intel -arm using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
public class Benchmarks
{
static void Main(string[] args)
{
BenchmarkSwitcher.FromAssembly(typeof(Benchmarks).Assembly).Run(args);
}
public static IEnumerable<object> TestData()
{
yield return new object[] { @"C:\a", @"C:\a\b" };
yield return new object[] { @"C:\a\", @"C:\a\b\c" };
yield return new object[] {
@"C:\projects\runtime\src\libraries",
@"C:\projects\runtime\src\libraries\System.Text.Json\tests"
};
yield return new object[] {
@"C:\a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p",
@"C:\a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z"
};
yield return new object[] {
@"C:\projects\runtime-main2\src\libraries\Microsoft.Extensions.DependencyInjection.Specification.Tests\src\Fakes",
@"C:\projects\runtime-main2\src\libraries\Microsoft.Extensions.DependencyInjection.Specification.Tests\src\"
};
yield return new object[] { @"C:\foo\bar", @"D:\foo\bar" };
yield return new object[] { @"C:\foo\bar\baz", @"C:\foo\bar\..\qux\." };
yield return new object[] { @"\\server\share\folder1", @"\\server\share\folder1\folder2\folder3" };
yield return new object[] {
@"C:\Program Files\MyApp",
@"C:\Program Files\MyApp\bin\Debug\net8.0"
};
}
[Benchmark]
[ArgumentsSource(nameof(TestData))]
public string GetFoo(string relativeTo, string path) =>
Path.GetRelativePath(relativeTo, path);
} |
xtqqczze
reviewed
Oct 27, 2025
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|
@EgorBot -intel -arm using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
public class Benchmarks
{
static void Main(string[] args)
{
BenchmarkSwitcher.FromAssembly(typeof(Benchmarks).Assembly).Run(args);
}
public static IEnumerable<object> TestData()
{
yield return new object[] { @"C:\a", @"C:\a\b" };
yield return new object[] { @"C:\a\", @"C:\a\b\c" };
yield return new object[] {
@"C:\projects\runtime\src\libraries",
@"C:\projects\runtime\src\libraries\System.Text.Json\tests"
};
yield return new object[] {
@"C:\a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p",
@"C:\a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z"
};
yield return new object[] {
@"C:\projects\runtime-main2\src\libraries\Microsoft.Extensions.DependencyInjection.Specification.Tests\src\Fakes",
@"C:\projects\runtime-main2\src\libraries\Microsoft.Extensions.DependencyInjection.Specification.Tests\src\"
};
yield return new object[] { @"C:\foo\bar", @"D:\foo\bar" };
yield return new object[] { @"C:\foo\bar\baz", @"C:\foo\bar\..\qux\." };
yield return new object[] { @"\\server\share\folder1", @"\\server\share\folder1\folder2\folder3" };
yield return new object[] {
@"C:\Program Files\MyApp",
@"C:\Program Files\MyApp\bin\Debug\net8.0"
};
}
[Benchmark]
[ArgumentsSource(nameof(TestData))]
public string GetFoo(string relativeTo, string path) =>
Path.GetRelativePath(relativeTo, path);
} |
stephentoub
reviewed
Oct 27, 2025
EgorBo
added
area-System.Runtime
reduce-unsafe
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Pull Request Overview
This PR modernizes the EqualStartingCharacterCount method by removing unsafe pointer arithmetic and replacing it with safe span-based operations. The implementation now leverages CommonPrefixLength for case-sensitive comparisons and falls back to a simple loop with char.ToUpperInvariant for case-insensitive scenarios.
Key changes:
- Replaced unsafe pointer-based character comparison with safe span operations
- Utilized
AsSpan().CommonPrefixLength()for case-sensitive prefix matching - Simplified case-insensitive comparison logic using indexed access instead of pointer arithmetic
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Tagging subscribers to this area: @dotnet/area-system-runtime |
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stephentoub
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xtqqczze
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Co-authored-by: xtqqczze <[email protected]>
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I wasn't able to detect any difference for
Path.GetRelativePathand the codegen is fairly close.if we want extra perf, we can vectorize this routine trivially for Linux/macOS (where paths are case-sensitives).
Given this API allocates a new string, it probably isn't supposed to be used on a hot path.