public void Remove()
{
this.myEnumerator.SetInvalid();
if (null != this.cursor)
{
DLNode <T> old = this.cursor;
if (this.cursor == this.head)
{
this.head = this.cursor.Next;
}
if (this.cursor == this.tail)
{
this.tail = this.cursor.Prev;
}
if (null != this.cursor.Next)
{
this.cursor.Next.Prev = this.cursor.Prev;
}
if (null != this.cursor.Prev)
{
this.cursor.Prev.Next = this.cursor.Next;
}
if (null != this.cursor.Next)
{
this.cursor = this.cursor.Next;
}
else
{
this.cursor = this.cursor.Prev;
}
Delete(old);
}
}
public void AddAfter(T item)
{
this.myEnumerator.SetInvalid();
DLNode <T> node = New(item);
if (null == this.tail)
{
this.tail = node;
this.head = node;
this.cursor = node;
}
else if (this.cursor == this.tail) // neither tail nor cursor are null
{
this.tail = node;
node.Prev = this.cursor;
node.Prev.Next = node;
this.cursor = node; // we set the cursor ti the inserted node
}
else
{
node.Next = this.cursor.Next;
node.Prev = this.cursor;
node.Next.Prev = node;
node.Prev.Next = node;
this.cursor = node; // we set the cursor to the inserted node
}
}
public bool MoveNext()
{
if (null == this.current)
{
this.current = this.root;
}
else
{
this.current = this.current.Next;
}
return(null != this.current);
}
public void MoveCursorPrev()
{
if (null != this.cursor)
{
if (null != this.cursor.Prev)
{
this.cursor = this.cursor.Prev;
}
}
else
{
cursor = this.head;
}
}
public void MoveCursorNext()
{
if (null != this.cursor)
{
if (null != this.cursor.Next)
{
this.cursor = this.cursor.Next;
}
}
else
{
cursor = this.tail;
}
}
private static void freeMemory()
{
DLNode <T> current = avail;
DLNode <T> next = avail;
while (null != current)
{
next = current.Next;
current.Item = null;
current.Prev = null;
current.Next = null;
current = next;
}
avail = null;
}
private static DLNode <T> New(T item)
{
DLNode <T> result = null;
if (null != avail)
{
result = avail;
avail = avail.Next;
result.Prev = null;
result.Next = null;
result.Item = item;
}
else
{
result = new DLNode <T>(item);
}
return(result);
}
public void SetValid(DLNode <M> start)
{
this.root = start;
}
private static void Delete(DLNode <T> node)
{
node.Item = null; node.Next = avail; avail = node;
}