/Utilities/Collections/SortHelper.cs

 1using System;
 2using System.Collections.Generic;
 3
 4namespace Delta.Utilities.Collections
 5{
 6	/// <summary>
 7	/// Sort helper
 8	/// </summary>
 9	public static class SortHelper
10	{
11		#region StableSort (Static)
12		/// <summary>
13		/// A stable insertion sort implementation.
14		/// This method can be used instead of the .NET Sort when stable sorting 
15		/// is needed because the .NET implementation of sorting is unstable.
16		/// Note that this method implements insertion sort which is
17		/// asymptotically less efficient than .NET Sort
18		/// (O(nlogn) QuickSort algorithm).
19		/// More info: http://www.csharp411.com/c-stable-sort/
20		/// </summary>
21		/// <typeparam name="T">The type of the elements to sort</typeparam>
22		/// <param name="list">The list with the elements to sort</param>
23		/// <param name="comparison">The comparison function</param>
24		public static void StableSort<T>(this IList<T> list,
25			Comparison<T> comparison)
26		{
27			// Insertion sort
28			int count = list.Count;
29			for (int j = 1; j < count; j++)
30			{
31				T key = list[j];
32
33				int i = j - 1;
34				for (; i >= 0 && comparison(list[i], key) > 0; i--)
35				{
36					list[i + 1] = list[i];
37				}
38				list[i + 1] = key;
39			} // for
40		}
41		#endregion
42	}
43}