C# SortNoAlloc for List, Array, etc...

ContainerExtensions.cs

using System.Collections.Generic;

public static class ContainerExtensions
{
	public static void SortNoAlloc<T>(this IList<T> list) where T : System.IComparable<T>
	{
		if(list.Count <= 1) return;
		QuickSort(list, 0, list.Count - 1);
	}

	private static int Partition<T>(IList<T> list, int low, int high) where T : System.IComparable<T>
	{
		T pivot = list[high];

		int i = (low - 1);

		for(int j = low; j < high; j++)
		{
			if(list[j].CompareTo(pivot) <= 0)
			{
				i++;
				T temp = list[i];
				list[i] = list[j];
				list[j] = temp;
			}
		}

		T otherTemp = list[i + 1];
		list[i + 1] = list[high];
		list[high] = otherTemp;

		return i + 1;
	}

	private static void QuickSort<T>(IList<T> list, int low, int high) where T : System.IComparable<T>
	{
		if(low < high)
		{
			int partitionIndex = Partition<T>(list, low, high);

			QuickSort(list, low, partitionIndex - 1);
			QuickSort(list, partitionIndex + 1, high);
		}
	}
}