Permutes a sequence of a specific type, and lets you enumerate through them

PermuteEnumerator`1.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

public class PermuteEnumerator<T>
	: IEnumerator<IEnumerable<T>>
	where T : IComparable
{

	T[] _data;
	int _length;
	bool _isReset = true;

	public PermuteEnumerator(IEnumerable<T> data)
	{
		if (data == null)
			throw new ArgumentNullException("data");

		_data = data.ToArray();
		_length = _data.Length;

		Reset();
		Current = _data;
	}

	static void Swap(T[] arr, int a, int b)
	{
		T tmp = arr[b];
		arr[b] = arr[a];
		arr[a] = tmp;
	}

	#region IEnumerator<T> Members

	public IEnumerable<T> Current { get; private set; }

	public void Dispose() { }

	object IEnumerator.Current
	{
		get { return Current; }
	}

	public bool MoveNext()
	{
		if (_isReset)
		{
			_isReset = false;
			return true;
		}

		// Find the largest i
		int i = _length - 2;
		while (i >= 0 && _data[i].CompareTo(_data[i + 1]) > 0)
			i--;

		// If i is smaller than 0, then there are no more permutations.
		if (i < 0)
			return false;

		// Find the largest element after vi but not larger than vi
		int k = _length - 1;
		while (_data[i].CompareTo(_data[k]) > 0)
			k--;
		Swap(_data, i, k);

		// Swap the last n-i elements
		k = 0;
		for (int j = i + 1; j < (_length + i) / 2 + 1; j++, k++)
			Swap(_data, j, _length - k - 1);

		return true;
	}

	public void Reset()
	{
		Array.Sort(_data);
		_isReset = true;
	}

	#endregion

}