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MurmurHash.Net

NuGet Build Status License

Extremely fast MurmurHash3 implementation with zero heap allocations

This is a fork of the System.Data.HashFunction.MurmurHash.

Differences

  • Faster (zero heap allocations via Spans, reduced class inheritance, bytes to uint conversion optimisations)
  • Only 32-bit output hash value. Maybe 128-bit will be supported in the future. But you can implement it by yourself and send me PR :)

Installation

This project is available as a NuGet package

Example

Some code 1. You can use traditional byte[]

uint hash = MurmurHash3.Hash32(bytes: new byte[]{1,2,3}, seed: 123456U);
Console.WriteLine(hash);

Output 1

3800434721

Some code 2. State-of-the-art Span<byte> and ReadOnlySpan<byte> also supported

ReadOnlySpan<byte> span = ...
uint hash = MurmurHash3.Hash32(bytes: span, seed: 123456U);

Benchmarks

// * Summary *

BenchmarkDotNet=v0.12.0, OS=macOS Mojave 10.14.6 (18G103) [Darwin 18.7.0]
Intel Core i7-7660U CPU 2.50GHz (Kaby Lake), 1 CPU, 4 logical and 2 physical cores
.NET Core SDK=3.1.100
  [Host]     : .NET Core 3.1.0 (CoreCLR 4.700.19.56402, CoreFX 4.700.19.56404), X64 RyuJIT
  DefaultJob : .NET Core 3.1.0 (CoreCLR 4.700.19.56402, CoreFX 4.700.19.56404), X64 RyuJIT

Byte[] to uint

Method Mean StdDev Ratio RatioSD Gen 0 Allocated
CRC32 40.73 us 0.696 us 3.32 0.06 - -
XxHash 197.13 us 10.995 us 15.65 0.62 87.8906 184000 B
MurMurHashByDarrenkopp 51.46 us 3.469 us 4.04 0.16 15.3198 32000 B
Blake2B 91.83 us 3.949 us 7.57 0.41 7.5684 16000 B
MurMurHashNet 12.28 us 0.122 us 1.00 0.00 - -

String to uint

Method Mean StdDev Ratio RatioSD Gen 0 Allocated
CRC32 65.63 us 1.385 us 3.00 0.08 15.2588 32000 B
XxHash 228.36 us 21.086 us 9.52 0.28 103.2715 216000 B
MurMurHashByDarrenkopp 77.14 us 2.490 us 3.53 0.15 30.6396 64000 B
Blake2B 119.69 us 2.443 us 5.46 0.18 22.9492 48000 B
MurMurHashNet 21.91 us 0.364 us 1.00 0.00 - -

Legend