public void Unlink(LinkedObject item)
{
if (item == null)
{
return;
}
if (item == Items)
{
Items = Items.Next;
if (Items != null)
{
Items.Previous = null;
}
}
else
{
if (item.Previous != null)
{
item.Previous.Next = item.Next;
}
if (item.Next != null)
{
item.Next.Previous = item.Previous;
}
}
}
public void Insert(LinkedObject first, LinkedObject item)
{
if (first == null)
{
item.Right = First;
item.Left = null;
if (First != null)
{
First.Left = item;
}
First = item;
}
else
{
var next = first.Right;
item.Right = next;
item.Left = first;
first.Right = item;
if (next != null)
{
next.Left = item;
}
}
}
public void Insert(LinkedObject first, LinkedObject item)
{
if (first == null)
{
item.Next = Items;
item.Previous = null;
if (Items != null)
{
Items.Previous = item;
}
Items = item;
}
else
{
LinkedObject next = first.Next;
item.Next = next;
item.Previous = first;
first.Next = item;
if (next != null)
{
next.Previous = item;
}
}
}
public void PushToBack(LinkedObject item)
{
if (item == null)
{
return;
}
Remove(item);
if (Items == null)
{
Items = item;
}
else
{
var current = Items;
while (current.Next != null)
{
current = current.Next;
}
current.Next = item;
item.Previous = current;
}
}
public void PushToBack(LinkedObject item)
{
if (item == null)
{
return;
}
Remove(item);
if (Items == null)
{
Items = item;
}
else
{
var current = Items;
while (current.Next != null)
{
current = current.Next;
}
current.Next = item;
Debug.Assert(item.Next == null, "[Append to last-next] item must be unlinked before.");
item.Next = null;
item.Previous = current;
}
}
public void Remove(LinkedObject item)
{
if (item == null)
{
return;
}
Unlink(item);
item.Right = null;
item.Left = null;
}
public void Remove(LinkedObject item)
{
if (item == null)
{
return;
}
Unlink(item);
item.Next = null;
item.Previous = null;
}
public LinkedObject GetLast()
{
LinkedObject last = Items;
while (last != null && last.Next != null)
{
last = last.Next;
}
return(last);
}
public void Clear()
{
if (Items != null)
{
LinkedObject item = Items;
Items = null;
while (item != null)
{
LinkedObject next = item.Next;
item.Next = null;
item = next;
}
}
}
public void MoveToFront(LinkedObject item)
{
if (item != null && item != First)
{
Unlink(item);
if (First != null)
{
First.Left = item;
}
item.Right = First;
item.Left = null;
First = item;
}
}
public void MoveToFront(LinkedObject item)
{
if (item != null && item != Items)
{
Unlink(item);
if (Items != null)
{
Items.Previous = item;
}
item.Next = Items;
item.Previous = null;
Items = item;
}
}
public void MoveToBack(LinkedObject item)
{
if (item != null)
{
Unlink(item);
var last = GetLast();
if (last == null)
{
First = item;
}
else
{
last.Right = item;
}
item.Left = last;
item.Right = null;
}
}
public void MoveToBack(LinkedObject item)
{
if (item != null)
{
Unlink(item);
LinkedObject last = GetLast();
if (last == null)
{
Items = item;
}
else
{
last.Next = item;
}
item.Previous = last;
item.Next = null;
}
}
public void PushToBack(LinkedObject item)
{
if (item == null)
{
return;
}
if (First == null)
{
First = item;
}
else
{
var current = First;
while (current.Right != null)
{
current = current.Right;
}
current.Right = item;
item.Left = current;
}
}
public void PushToBack(LinkedObject item)
{
if (item == null)
{
return;
}
Remove(item);
if (Items == null)
{
Items = item;
}
else
{
LinkedObject last = GetLast();
last.Next = item;
Debug.Assert(item.Next == null, "[Append to last-next] item must be unlinked before.");
item.Next = null;
item.Previous = last;
}
}
public void Unlink(LinkedObject item)
{
if (item == null)
{
return;
}
if (item == First)
{
First = First.Right;
if (First != null)
{
First.Left = null;
}
}
else
{
item.Left.Right = item.Right;
if (item.Right != null)
{
item.Right.Left = item.Left;
}
}
}
