///<summary>Insert element at the begining of the list</summary>
///<param name="value">Value to insert</param>
public override void Prepend(T value)
{
size++;
DLListNode <T> newNode = new DLListNode <T>(value, beforeHeadNode, beforeHeadNode.Next);
beforeHeadNode.SetNext(newNode);
beforeHeadNode.Next.SetPrevious(newNode);
}
///<summary>Insert element at the end of the list</summary>
///<param name="value">Value to append</param>
public override void Append(T value)
{
size++;
DLListNode <T> after = afterEndNode.Previous;
DLListNode <T> newNode = new DLListNode <T>(value, after, afterEndNode);
after.SetNext(newNode);
afterEndNode.SetPrevious(newNode);
}
///<summary>Creates new instance of <see cref="DLList{T}"></summary>
public DLList()
{
this.size = 0;
this.beforeHeadNode = new DLListNode <T>(default(T), null, afterEndNode);
this.afterEndNode = new DLListNode <T>(default(T), beforeHeadNode, null);
//its little tricky, prev and after always points to itself
//this will help in IEnumerator implementation in DLListIterator class
beforeHeadNode.SetPrevious(beforeHeadNode);
beforeHeadNode.SetNext(afterEndNode);
afterEndNode.SetNext(afterEndNode);
afterEndNode.SetPrevious(beforeHeadNode);
}
public override void Remove(T value)
{
DLListIterator <T> toRemoveIterator;
int index = GetIndexOf(value, out toRemoveIterator);
if (index > -1)
{
DLListNode <T> toDelete = toRemoveIterator.GetCurrentNode();
toDelete.Previous.SetNext(toDelete.Next);
toDelete.Next.SetPrevious(toDelete.Previous);
//remove references
toDelete.SetNext(null);
toDelete.SetPrevious(null);
}
}
public void SetPrevious(DLListNode <T> previousNode)
{
this.Previous = previousNode;
}
public void SetNext(DLListNode <T> nextNode)
{
this.Next = nextNode;
}
public DLListNode(T value, DLListNode <T> previous, DLListNode <T> next)
{
this.Value = value;
this.Previous = previous;
this.Next = next;
}
public void Reset()
{
this.current = beforeHeadNode;
}
public bool MovePrevious()
{
current = current.Previous;
return(current != beforeHeadNode);
}
public bool MoveNext()
{
current = current.Next;
return(current != afterEndNode);
}
public DLListIterator(DLListNode <T> beforeHeadNode, DLListNode <T> afterEndNode)
{
this.beforeHeadNode = beforeHeadNode;
this.afterEndNode = afterEndNode;
this.current = beforeHeadNode;
}