A fast and low allocation StringBuilder for .NET.
Install the package:
PM> Install-Package LinkDotNet.StringBuilder
Afterwards use the package as follow:
using LinkDotNet.StringBuilder; // Namespace of the package
ValueStringBuilder stringBuilder = new ValueStringBuilder();
stringBuilder.AppendLine("Hello World");
string result = stringBuilder.ToString();
There are also smaller helper functions, which enable you to use ValueStringBuilder
without any instance:
using LinkDotNet.StringBuilder;
_ = ValueStringBuilder.Concat("Hello ", "World"); // "Hello World"
_ = ValueStringBuilder.Concat("Hello", 1, 2, 3, "!"); // "Hello123!"
The dotnet version of the StringBuilder
is an all-purpose version that normally fits a wide variety of needs.
But sometimes low allocation is key. Therefore I created the ValueStringBuilder
. It is not a class but a ref struct
that tries to do as less allocations as possible.
If you want to know how the ValueStringBuilder
works and why it uses allocations and is even faster, check out this blog post.
The blog goes into a bit more in detail about how it works with a simplistic version of the ValueStringBuilder
.
The library is not meant as a general replacement for the StringBuilder
shipped with the .net framework itself. You can head over to the documentation and read about the "Known limitations".
The library works best for a small to medium amount of strings (not multiple 100'000 characters, even though it can be still faster and uses fewer allocations). At any time you can convert the ValueStringBuilder
to a "normal" StringBuilder
and vice versa.
The normal use case is to add concatenate strings in a hot path where the goal is to put as minimal pressure on the GC as possible.
More detailed documentation can be found here. It is really important to understand how the ValueStringBuilder
works so that you did not run into weird situations where performance/allocations can even rise.
The following table gives you a small comparison between the StringBuilder
which is part of .NET, ZString
and the ValueStringBuilder
:
BenchmarkDotNet=v0.13.2, OS=macOS Monterey 12.6.1 (21G217) [Darwin 21.6.0]
Apple M1 Pro, 1 CPU, 10 logical and 10 physical cores
.NET SDK=7.0.100-rc.2.22477.23
[Host] : .NET 6.0.10 (6.0.1022.47605), Arm64 RyuJIT AdvSIMD
DefaultJob : .NET 6.0.10 (6.0.1022.47605), Arm64 RyuJIT AdvSIMD
| Method | Mean | Error | StdDev | Ratio | RatioSD | Gen0 | Allocated | Alloc Ratio |
|------------------------------- |-----------:|---------:|---------:|------:|--------:|--------:|----------:|------------:|
| DotNetStringBuilder | 227.3 ns | 1.31 ns | 1.22 ns | 1.00 | 0.00 | 0.7114 | 1488 B | 1.00 |
| ValueStringBuilder | 128.7 ns | 0.57 ns | 0.53 ns | 0.57 | 0.00 | 0.2677 | 560 B | 0.38 |
| ValueStringBuilderPreAllocated | 113.9 ns | 0.67 ns | 0.60 ns | 0.50 | 0.00 | 0.2677 | 560 B | 0.38 |
| ZStringBuilderUtf8 | 1,976.1 ns | 17.33 ns | 15.37 ns | 8.69 | 0.08 | 31.2500 | 66120 B | 44.44 |
| ZStringBuilderUtf16 | 1,888.2 ns | 18.50 ns | 16.40 ns | 8.30 | 0.09 | 31.2500 | 66120 B | 44.44 |
For more comparison check the documentation.
Another benchmark shows that this ValueStringBuilder
uses less memory when it comes to appending ValueTypes
such as int
, double
, ...
| Method | Mean | Error | StdDev | Gen 0 | Allocated |
|-------------------- |---------:|---------:|---------:|-------:|----------:|
| DotNetStringBuilder | 17.21 us | 0.622 us | 1.805 us | 1.5259 | 6 KB |
| ValueStringBuilder | 16.24 us | 0.496 us | 1.462 us | 0.3357 | 1 KB |
Checkout the Benchmark for a more detailed comparison and setup.