public void SetAfter(T after, T data)
{
if (Head != null)
{
var current = Head.Next;
while (current != null)
{
if (current.Data.Equals(after))
{
if (current.Next != null)
{
var item = new TwoWayLinkedListItem <T>(data);
current.Next.Previous = item;
item.Next = current.Next;
current.Next = item;
item.Previous = current;
Count++;
return;
}
else
{
AddData(data);
return;
}
}
current = current.Next;
}
}
else
{
SetHeadAndTail(data);
}
}
private void SetHeadAndTail(T data)
{
var item = new TwoWayLinkedListItem <T>(data);
Head = item;
Tail = item;
Count = 1;
}
public void AddData(T data)
{
if (Head != null)
{
var item = new TwoWayLinkedListItem <T>(data);
item.Previous = Tail;
Tail.Next = item;
Tail = item;
Count++;
}
else
{
SetHeadAndTail(data);
}
}
public void AlterHead(T data)
{
if (Head != null)
{
var item = new TwoWayLinkedListItem <T>(data);
Head.Previous = item;
item.Next = Head;
Head = item;
Count++;
}
else
{
SetHeadAndTail(data);
}
}
public void Delete(T data)
{
if (Head != null)
{
var item = new TwoWayLinkedListItem <T>(data);
if (Head.Data.Equals(item.Data))
{
Head = Head.Next;
Count--;
return;
}
var current = Head.Next;
var previous = Head;
while (current != null)
{
if (current.Data.Equals(item.Data))
{
if (current.Next != null)
{
previous.Next = current.Next;
current.Next.Previous = previous;
Count--;
return;
}
else
{
current.Previous = null;
previous.Next = null;
Count--;
return;
}
}
previous = current;
current = current.Next;
}
}
else
{
throw new ArgumentNullException("Two way linked list is empty!");
}
}
