public void TestValuesAndWrapAround()
{
var d = new Deque <int>(4);
d.AddLast(1); // internally it contains [H:1, 2, 3, 4]
d.AddLast(2);
d.AddLast(3);
d.AddLast(4);
Assert.IsTrue(d.PeekFirst() == 1 & d.PeekLast() == 4);
d.RemoveFirst();
d.RemoveLast(); // now it's [0, H:2, 3, 0]
Assert.IsTrue(d.Count == 2 && d.Capacity == 4);
Assert.IsTrue(d.PeekFirst() == 2 & d.PeekLast() == 3);
d.AddLast(4);
d.RemoveFirst(); // now it's [0, 0, H:3, 4]
Assert.IsTrue(d.Count == 2 && d.Capacity == 4);
Assert.IsTrue(d.PeekFirst() == 3 & d.PeekLast() == 4);
d.AddLast(5);
d.RemoveFirst(); // now it's [5, 0, 0, H:4]
Assert.IsTrue(d.Count == 2 && d.Capacity == 4);
Assert.IsTrue(d.PeekFirst() == 4 & d.PeekLast() == 5);
d.AddFirst(3);
d.AddFirst(2); // now it's [5, H:2, 3, 4]
Assert.IsTrue(d.Count == 4 && d.Capacity == 4);
Assert.IsTrue(d.PeekFirst() == 2 & d.PeekLast() == 5);
d.AddFirst(1); // reallocated to [H:1, 2, 3, 4, 5, 0, 0, 0]
d.AddFirst(0); // now it's [1, 2, 3, 4, 5, 0, 0, H:0]
Assert.IsTrue(d.Count == 6 && d.Capacity == 8);
Assert.IsTrue(d.PeekFirst() == 0 & d.PeekLast() == 5);
var arr = d.ToArray();
var exp = new int[] { 0, 1, 2, 3, 4, 5 };
Assert.IsTrue(arr.Length == exp.Length);
for (int i = 0; i < arr.Length; i++)
{
Assert.IsTrue(arr[i] == exp[i]);
}
}
/// <summary>
/// Removes and returns the head element of the queue, or null if the queue is empty.
/// Also activates the next element in the queue, if one exists.
/// </summary>
/// <returns></returns>
public T Dequeue()
{
if (IsEmpty)
{
return(null);
}
T head = _queue.PeekFirst();
head.OnDeactivated(false);
head.OnDequeued(false);
_queue.RemoveFirst();
if (!IsEmpty)
{
_queue.PeekFirst().OnActivated();
}
return(head);
}