public DequeElem <T> DetachTail()
{
if (tail == null)
{
throw new ApplicationException("Can't pop from an empty deque");
}
var tmp = tail;
tail = tail.prev;
if (tail != null)
{
tail.next = null;
}
else // tail == null
{
head = null;
}
Count--;
tmp.next = null;
tmp.prev = null;
return(tmp);
}
public void PushHead(DequeElem <T> newElem)
{
Count++;
if (Count == 1) // => it was 0 before increment
{
head = newElem;
tail = newElem;
return;
}
newElem.next = head;
head.prev = newElem;
head = newElem;
}
public void Bubble(DequeElem <T> elem)
{
if (elem == head)
{
return;
}
if (elem == tail)
{
DetachTail(); // changes elem
}
else // now guaranteed to be in the middle of the deque
{
elem.prev.next = elem.next;
elem.next.prev = elem.prev;
Count--;
elem.prev = null;
elem.next = null;
}
PushHead(elem);
}
public CacheDeque()
{
Count = 0;
head = null;
tail = null;
}