/// <summary>
/// Tries to get the value associated with 'key', returning true if it's found and
/// false if it's not present.
/// </summary>
public bool TryGetValue(TKey key, out TValue value)
{
KeyInfo storedValue;
if (_dict.TryGetValue(key, out storedValue))
{
CustomLinkedListNode <TKey> node = storedValue.List;
if (node.Previous != null)
{
// move us to the head of the list...
_list.Remove(node);
_list.AddFirst(node);
}
value = storedValue.Value;
return(true);
}
value = default(TValue);
return(false);
}
public void RemoveLast()
{
if (_count == 0)
{
throw new InvalidOperationException("List empty");
}
var node = _lastNode;
_lastNode = _lastNode.Previous;
_lastNode.Next = null;
node.List = null;
node.Previous = null;
_count--;
if (_lastNode == null)
{
_firstNode = null;
}
}
public void AddFirst(CustomLinkedListNode <T> node)
{
if (node.List != null)
{
throw new InvalidOperationException("Node belongs to another list");
}
if (_firstNode != null)
{
_firstNode.Previous = node;
}
node.List = this;
node.Next = _firstNode;
_count++;
_firstNode = node;
if (_lastNode == null)
{
_lastNode = node;
}
}
/// <summary>
/// Adds a new element to the cache, replacing and moving it to the front if the
/// element is already present.
/// </summary>
public void Add(TKey key, TValue value)
{
KeyInfo keyInfo;
if (_dict.TryGetValue(key, out keyInfo))
{
// remove original entry from the linked list
_list.Remove(keyInfo.List);
}
else if (_list.Count == _maxSize)
{
// we've reached capacity, remove the last used element...
CustomLinkedListNode <TKey> node = _list.Last;
_list.RemoveLast();
bool res = _dict.Remove(node.Value);
Debug.Assert(res);
}
// add the new entry to the head of the list and into the dictionary
CustomLinkedListNode <TKey> listNode = new CustomLinkedListNode <TKey>(key);
_list.AddFirst(listNode);
_dict[key] = new CacheDict <TKey, TValue> .KeyInfo(value, listNode);
}
public void Remove(CustomLinkedListNode <T> node)
{
if (node == null)
{
throw new ArgumentNullException("node is null");
}
if (node.List != this)
{
throw new InvalidOperationException("Node belongs to another list");
}
if (node.Previous != null)
{
node.Previous.Next = node.Next;
}
else
{
_firstNode = node.Next;
}
if (node.Next != null)
{
node.Next.Previous = node.Previous;
}
else
{
_lastNode = node.Previous;
}
_count--;
node.List = null;
node.Next = null;
node.Previous = null;
}
internal KeyInfo(TValue value, CustomLinkedListNode <TKey> list)
{
Value = value;
List = list;
}
