private void MoveToFront(LRUPrefixTreeMapNode newNode)
{
if (_head == newNode) // If it's already the head, stop
{
return;
}
if (_tail == newNode && newNode.Prev != null) // If it's the tail and it has a previous node, aka is not also the head
{
_tail = newNode.Prev;
_tail.Next = null;
}
if (_head != null)
{
_head.Prev = newNode;
if (_head.Next == newNode)
{
_head.Next = newNode.Next;
newNode.Next.Prev = _head;
}
}
newNode.Prev = null;
newNode.Next = _head;
_head = newNode;
}
private void RemoveLRU()
{
if (_map.Count == _capacity)
{
RemoveWordFromTree(_tail.Value);
_map.Remove(_tail.Value);
_tail.Prev.Next = null;
_tail = _tail.Prev;
}
}
private void AddToMap(LRUPrefixTreeNode node)
{
if (_map.ContainsKey(node))
{
MoveToFront(_map[node]);
}
else
{
var mapNode = new LRUPrefixTreeMapNode(node);
if (_tail != null)
{
RemoveLRU();
}
else
{
_tail = mapNode;
}
MoveToFront(mapNode);
_map.Add(node, mapNode);
}
}