public Node RemoveEnd()
{
Node oldTail = _tail;
if (_tail == null) // no nodes
{
return null;
}
else if (_head == _tail) //one node
{
_head = null;
_tail = null;
}
else //two or more nodes
{
Node secondLast = _tail.Parent;
_tail = secondLast;
_tail.SetChild(null);
}
Size--;
oldTail.SetChild(null);
oldTail.SetParent(null);
return oldTail;
}
public void GetTest()
{
LRUDoublyLinkedList dll = new LRUDoublyLinkedList();
Assert.IsNull(dll.Get(0));
Assert.IsNull(dll.Get(5));
try
{
dll.Get(-1);
Assert.Fail("Should throw an exception");
}
catch (InvalidElementIndexException) {}
Node n0 = new Node(null, null, new Element(new byte[0]), 0);
dll.Insert(n0);
Assert.AreEqual(dll.Get(0), n0);
Assert.IsNull(dll.Get(1));
Assert.IsNull(dll.Get(2));
Node n1 = new Node(null, null, new Element(new byte[0]), 1);
dll.Insert(n1);
Assert.AreEqual(dll.Get(0), n1);
Assert.AreEqual(dll.Get(1), n0);
Assert.AreEqual(dll.Get(0), n0);
Assert.IsNull(dll.Get(2));
}
public Node(Node child, Node parent, Element element, int eleIdx)
{
Child = child;
Parent = parent;
Element = element;
ElementIndex = eleIdx;
}
public void NodeCtorTest()
{
Element ele = new Element(new byte[0]);
int elementIdx = 0;
Node parent = new Node(null, null, ele, elementIdx);
Node child = new Node(null, null, ele, elementIdx);
NodeCtorTestAssert(elementIdx, ele, parent, child);
}
public void SetChildTest()
{
Node child = new Node(null, null, new Element(new byte[0]), 0);
Node n = new Node(null, null, new Element(new byte[0]), 1);
n.SetChild(child);
Assert.AreEqual(child, n.Child);
}
public void SetParentTest()
{
Node parent = new Node(null, null, new Element(new byte[0]), 0);
Node n = new Node(null, null, new Element(new byte[0]), 1);
n.SetParent(parent);
Assert.AreEqual(parent, n.Parent);
}
public void AddToCache(Element element, int elementIdx)
{
Node cachedNode;
if (_index.TryGetValue(elementIdx, out cachedNode))
{
cachedNode.SetElement(element);
_cacheList.MoveToHead(cachedNode);
}
else
{
Node node = new Node(null, null, element, elementIdx);
_cacheList.Insert(node);
_index.Add(elementIdx, node);
}
if (_cacheList.Size > _cacheSize)
RemoveLast();
}
public void MoveToHead(Node n)
{
if (n == _head)
{
//already the _head
}
else if (n == _tail) // the node to move is the tail
{
Debug.Assert(_tail.Parent != null);
_tail.Parent.SetChild(null);
_tail = _tail.Parent;
InsertAtHead(n);
}
else // the node is in the middle
{
n.Parent.SetChild(n.Child);
n.Child.SetParent(n.Parent);
InsertAtHead(n);
}
}
public void MoveToHeadTest()
{
LRUDoublyLinkedList dll = new LRUDoublyLinkedList();
Node n0 = new Node(null, null, new Element(new byte[0]), 0);
dll.Insert(n0);
dll.MoveToHead(n0);
Assert.AreEqual(n0, dll.Get(0));
Assert.AreEqual(1, dll.Size);
Node n1 = new Node(null, null, new Element(new byte[0]), 1);
dll.Insert(n1);
dll.MoveToHead(n0);
Assert.AreEqual(n0, dll.Get(0));
Assert.AreEqual(2, dll.Size);
Node n2 = new Node(null, null, new Element(new byte[0]), 2);
dll.Insert(n2);
dll.MoveToHead(n0);
Assert.AreEqual(n0, dll.Get(0));
Assert.AreEqual(3, dll.Size);
}
public void Insert(Node n)
{
InsertAtHead(n);
Size++;
}
public void RemoveEndTest()
{
LRUDoublyLinkedList dll = new LRUDoublyLinkedList();
Assert.IsNull(dll.RemoveEnd());
Node n0 = new Node(null, null, new Element(new byte[0]), 0);
dll.Insert(n0);
dll.RemoveEnd();
Assert.IsNull(dll.Get(0));
Assert.AreEqual(0, dll.Size);
dll.Insert(n0);
Node n1 = new Node(null, null, new Element(new byte[0]), 1);
dll.Insert(n1);
dll.RemoveEnd();
Assert.AreEqual(dll.Get(0), n1);
Assert.IsNull(dll.Get(1));
Assert.AreEqual(1, dll.Size);
}
private void InsertOneTest()
{
LRUDoublyLinkedList dll = new LRUDoublyLinkedList();
Node n0 = new Node(null, null, new Element(new byte[0]), 0);
Assert.AreEqual(0, dll.Size);
dll.Insert(n0);
Assert.AreEqual(n0, dll.Get(0));
Assert.AreEqual(1, dll.Size);
}
public void SetParent(Node parent)
{
Parent = parent;
}
public void SetChild(Node child)
{
Child = child;
}
private static void NodeCtorTestAssert(int elementIdx, Element ele, Node parent, Node child)
{
Node n = new Node(child, parent, ele, elementIdx);
Assert.AreEqual(n.Element, ele);
Assert.AreEqual(n.ElementIndex, elementIdx);
Assert.AreEqual(n.Child, child);
Assert.AreEqual(n.Parent, parent);
}
private void InsertAtHead(Node n)
{
n.SetParent(null);
n.SetChild(_head);
if (_head == null) // no nodes yet
{
Debug.Assert(_tail == null);
_tail = n;
}
if (_head != null) // at least one node in the list
{
_head.SetParent(n);
}
_head = n;
}
private void InsertMoreThanTwoTest()
{
LRUDoublyLinkedList dll = new LRUDoublyLinkedList();
Node n0 = new Node(null, null, new Element(new byte[0]), 0);
dll.Insert(n0);
Node n1 = new Node(null, null, new Element(new byte[0]), 1);
dll.Insert(n1);
Node n2 = new Node(null, null, new Element(new byte[0]), 2);
dll.Insert(n2);
Assert.AreEqual(n2, dll.Get(0));
Assert.AreEqual(n1, dll.Get(1));
Assert.AreEqual(n0, dll.Get(2));
Assert.AreEqual(3, dll.Size);
}