InlineCollection

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Overview

InlineCollection is a library that provides zero-allocation stack-based collections for Unity.

Since Unity uses a relatively old C# version (C# 10), it cannot utilize features like InlineArray or collection expressions that are available in C# 12 and later.

While stackalloc can be used in Unity, it can only create Spans of unmanaged types and cannot allocate arrays of managed types on the stack.

This library adds:

• An InlineCollection feature equivalent to the InlineArray available in C# 12 and later
• A convenient functionality to convert ValueTuple to Span

Installation

.NET CLI

dotnet add package InlineCollection

Unity

1. Install NuGetForUnity
2. Open Nuget window and install InlineCollection

Usage

Tuple To Span

You can convert a ValueTuple to a Span:

var span = (1, 2, 3).AsSpan();

foreach (var i in span)
{
    Debug.Log(i);
}

Note that all elements in the tuple must be of the same type.

InlineCollection

You can create array-like structures by adding the InlineCollection attribute to a partial struct:

[InlineCollection(length: 3)]
public partial struct SampleInlineCollection<T> {}

Usage example:

using InlineCollection;

var sample = new SampleInlineCollection<string>("a", "b", "C");

sample[0] = "a";

foreach (var s in sample)
{
    Debug.Log(s);
}

You can also convert it to a Span:

Span<string> span = sample.AsSpan();

Additionally, you can specify a specific element type by adding type information as an argument to the InlineCollection attribute:

[InlineCollection(elementType: typeof(int), length: 3)]
public partial struct SampleInlineCollection {}

Example:

var sample = new SampleInlineCollection(0, 1, 2);