SpanDex

Utilities to read/write primitives from/to spans easily. Uses the C# Span struct.

Getting Started

Install the Nuget Package

Motivation

Reading/writing spans can be a chore, keeping track of where you're up to reading a span. This lib lets you simplify this:

var one = BinaryPrimitives.ReadUInt16LittleEndian(span.Slice(3, 2));
var two = BinaryPrimitives.ReadUInt32LittleEndian(span.Slice(5, 4));
var three = BinaryPrimitives.ReadUInt16BigEndian(span.Slice(9, 2));

to this:

int cursor = 0;
var one = span.ReadUInt16LittleEndian(ref cursor);
var two = span.ReadUInt32LittleEndian(ref cursor);
var three = span.ReadUInt16BigEndian(ref cursor);

or:

var spanReader = new SpanReader(span);
var one = spanReader.ReadUInt16LittleEndian();
var two = spanReader.ReadUInt32LittleEndian();
var three = spanReader.ReadUInt16BigEndian();

This lib is based around the System.Buffers.Binary.BinaryPrimitives class, with some other methods sprinkled in for some spice.

Included types

• SpanReader for reading a span
• SpanWriter for creating and writing to a span; initialize with size or Memory<byte>
• A tonne of extension methods, applicable to Span<byte> and ReadOnlySpan<byte> - all ripped straight from System.Buffers.Binary.BinaryPrimitives, as well as:
• span.ReadSpan() - same as slice, but keeps track of where you're up to
• span.ReadASCIIString() - does what it says on the packet
• span.ReadUTF8String() - I think you get the drift

Benchmark Results

BenchmarkDotNet=v0.11.5, OS=Windows 10.0.19041
Intel Core i7-9750H CPU 2.60GHz, 1 CPU, 12 logical and 6 physical cores
.NET Core SDK=5.0.104
  [Host]     : .NET Core 2.2.8 (CoreCLR 4.6.28207.03, CoreFX 4.6.28208.02), 64bit RyuJIT
  DefaultJob : .NET Core 2.2.8 (CoreCLR 4.6.28207.03, CoreFX 4.6.28208.02), 64bit RyuJIT

Method	N	Mean	Error	StdDev	Rank	Gen 0	Gen 1	Gen 2	Allocated
SpanReader	1000	1,201.3 ns	22.18 ns	20.75 ns	3	-	-	-	-
BitConvert	1000	947.9 ns	18.67 ns	27.37 ns	2	-	-	-	-
Manual	1000	553.7 ns	10.96 ns	10.77 ns	1	-	-	-	-
SpanReader	10000	13,152.5 ns	262.35 ns	376.25 ns	6	-	-	-	-
BitConvert	10000	9,786.4 ns	168.66 ns	187.47 ns	5	-	-	-	-
Manual	10000	5,379.4 ns	107.46 ns	182.47 ns	4	-	-	-	-