using System;

using System.Collections.Generic;



namespace Delta.Utilities.Collections

{

	/// <summary>

	/// Sort helper

	/// </summary>

	public static class SortHelper

	{

		#region StableSort (Static)

		/// <summary>

		/// A stable insertion sort implementation.

		/// This method can be used instead of the .NET Sort when stable sorting 

		/// is needed because the .NET implementation of sorting is unstable.

		/// Note that this method implements insertion sort which is

		/// asymptotically less efficient than .NET Sort

		/// (O(nlogn) QuickSort algorithm).

		/// More info: http://www.csharp411.com/c-stable-sort/

		/// </summary>

		/// <typeparam name="T">The type of the elements to sort</typeparam>

		/// <param name="list">The list with the elements to sort</param>

		/// <param name="comparison">The comparison function</param>

		public static void StableSort<T>(this IList<T> list,

			Comparison<T> comparison)

		{

			// Insertion sort

			int count = list.Count;

			for (int j = 1; j < count; j++)

			{

				T key = list[j];



				int i = j - 1;

				for (; i >= 0 && comparison(list[i], key) > 0; i--)

				{

					list[i + 1] = list[i];

				}

				list[i + 1] = key;

			} // for

		}

		#endregion

	}

}