public void Prepend(T value)
{
var node = new DoubleLinkedListItem <T>(value);
if (Head == null)
{
Head = Tail = new DoubleLinkedListItem <T>(value);
}
else
{
node.NextItem = Head;
Head.PreviousItem = node;
Head = node;
}
}
public bool DeleteTail()
{
if (Tail != null)
{
if (Tail.PreviousItem != null)
{
Tail = Tail.PreviousItem;
Tail.NextItem = null;
}
else
{
Tail = Head = null;
}
return(true);
}
return(false);
}
public bool DeleteHead()
{
if (Head != null)
{
if (Head.NextItem != null)
{
Head = Head.NextItem;
Head.PreviousItem = null;
}
else
{
Tail = Head = null;
}
return(true);
}
return(false);
}
public bool Delete(T value)
{
if (Head == null)
{
return(false);
}
var current = Head;
while (current.NextItem != null)
{
if (current.Value.Equals(value))
{
if (current != Head)
{
current.PreviousItem.NextItem = current.NextItem;
current.NextItem.PreviousItem = current.PreviousItem;
}
else
{
current.PreviousItem = null;
Head = current;
}
return(true);
}
current = current.NextItem;
}
if (current.Value.Equals(value))
{
Tail = current.PreviousItem;
Tail.NextItem = null;
return(true);
}
return(false);
}
public void Reset()
{
_currentItem = null;
}
public bool MoveNext()
{
_currentItem = _currentItem == null ? _list.Head : _currentItem.NextItem;
return(_currentItem != null);
}
public DoubleLinkedList(T value)
{
Head = Tail = new DoubleLinkedListItem <T>(value);
}