MemoryReaders

The MemoryReaders package provides SequenceReader<T>-like APIs for Span<T> and Memory<T> instances, with a similar focus on performance and minimal-or-zero heap allocations.

The SpanReader<T> and MemoryReader<T> structures afford the ability to read and search Span/Memory instances in a forward-only manner (rewinding is supported).

MemoryReaders targets netstandard2.1.

Install

MemoryReaders is available on NuGet

dotnet add package carlst99.MemoryReaders

Usage

The SpanReader<T> can be constructed over any ReadOnlySpan<T> instance, and likewise for the MemoryReader<T>.

const string DataString = "The quick brown fox jumped over the lazy dog";

SpanReader<char> spanReader = new(DataString.AsSpan());
MemoryReader<char> memoryReader = new(DataString.AsMemory());

spanReader.TryReadTo
(
    out ReadOnlySpan<char> readData,
    delimiter: "fox".AsSpan(),
    advancePastDelimiter: false
);

bool foundQ = memoryReader.TryAdvanceTo('q', advancePastDelimiter: true);
if (foundQ && memoryReader.IsNext("uick".AsSpan()))
    Console.WriteLine("That was fast!");

Performance

MemoryReaders is not thoroughly benchmarked, but comparisons have been made between the SequenceReader, SpanReader and MemoryReader implementations for the IsNext, TryAdvanceTo and TryReadTo methods.

The results of benchmarking TryReadTo appear typical of the package, and are as follows:

// * Summary *

BenchmarkDotNet=v0.13.1, OS=Windows 10.0.22621
AMD Ryzen 5 3600, 1 CPU, 12 logical and 6 physical cores
.NET SDK=6.0.402
  [Host]     : .NET 6.0.10 (6.0.1022.47605), X64 RyuJIT
  DefaultJob : .NET 6.0.10 (6.0.1022.47605), X64 RyuJIT


|                  Method | Categories |      Mean |    Error |   StdDev | Ratio |
|------------------------ |----------- |----------:|---------:|---------:|------:|
|     UsingSequenceReader |  ShortData |  24.54 ns | 0.097 ns | 0.086 ns |  1.00 |
|       UsingMemoryReader |  ShortData |  17.30 ns | 0.051 ns | 0.042 ns |  0.71 |
|         UsingSpanReader |  ShortData |  15.02 ns | 0.017 ns | 0.015 ns |  0.61 |
|                         |            |           |          |          |       |
| UsingLongSequenceReader |   LongData | 139.89 ns | 0.637 ns | 0.565 ns |  1.00 |
|   UsingLongMemoryReader |   LongData | 131.52 ns | 0.863 ns | 0.721 ns |  0.94 |
|     UsingLongSpanReader |   LongData | 128.04 ns | 0.979 ns | 0.916 ns |  0.91 |