public static DoublyLinkedList <T> Append <T>(DoublyLinkedList <T> left, DoublyLinkedList <T> right)
{
if (left is null)
{
ThrowLeftNull();
}
if (right is null)
{
ThrowRightNull();
}
var result = new DoublyLinkedList <T>();
result.AddLast(left);
result.AddLast(right);
return(result);
void ThrowLeftNull() => throw new ArgumentNullException(nameof(left));
void ThrowRightNull() => throw new ArgumentNullException(nameof(right));
}
public DoublyLinkedList <T> Reverse()
{
var list = new DoublyLinkedList <T>
{
head = null,
tail = null,
count = count,
version = 0,
};
var current = head;
if (!(current is null))
{
list.head = list.tail = new Node
{
List = list,
Value = current.Value,
Next = null,
Previous = null,
};
current = current.Next;
while (!(current is null))
{
var node = new Node
{
List = list,
Value = current.Value,
Next = list.head,
Previous = null,
};
list.head.Previous = node;
list.head = node;
current = current.Next;
}
}
return(list);
}
internal ForwardEnumeration(DoublyLinkedList <T> list) => this.list = list;
internal ReverseEnumeration(DoublyLinkedList <T> list)
{
this.list = list;
}
public void AddLastFrom(DoublyLinkedList <T> list, bool reversed = false)
{
if (list is null)
{
ThrowListNull();
}
if (list.Count == 0)
{
return;
}
Node tempHead = null;
Node tempTail = null;
if (reversed)
{
AssignReversed();
}
else
{
Assign();
}
if (IsEmpty)
{
head = tempHead;
tail = tempTail;
}
else
{
tail.Next = tempHead;
tempHead.Previous = tail;
tail = tempTail;
}
count += list.count;
version++;
list.Invalidate();
void ThrowListNull() => throw new ArgumentNullException(nameof(list));
void Assign()
{
var current = list.head;
while (!(current is null))
{
current.List = this;
current = current.Next;
}
tempHead = list.head;
tempTail = list.tail;
}
void AssignReversed()
{
var current = list.head;
var next = current.Next;
current.List = this;
current.Next = null;
current.Previous = null;
tempHead = tempTail = current;
current = next;
while (!(current is null))
{
next = current.Next;
current.List = this;
current.Next = tempHead;
current.Previous = null;
tempHead.Previous = current;
tempHead = current;
current = next;
}
}
}
public void AddLast(DoublyLinkedList <T> list, bool reversed = false)
{
if (list is null)
{
ThrowListNull();
}
if (list.Count == 0)
{
return;
}
Node tempHead = null;
Node tempTail = null;
var current = list.head;
tempHead = tempTail = new Node
{
List = this,
Value = current.Value,
Next = null,
Previous = null,
};
if (reversed)
{
AssignReversed();
}
else
{
Assign();
}
if (IsEmpty)
{
head = tempHead;
tail = tempTail;
}
else
{
tail.Next = tempHead;
tempHead.Previous = tail;
tail = tempTail;
}
count += list.count;
version++;
void ThrowListNull() => throw new ArgumentNullException(nameof(list));
void Assign()
{
current = current.Next;
while (!(current is null))
{
var node = new Node
{
List = this,
Value = current.Value,
Next = null,
Previous = tempTail,
};
tempTail.Next = node;
tempTail = node;
current = current.Next;
}
}
void AssignReversed()
{
current = current.Next;
while (!(current is null))
{
var node = new Node
{
List = this,
Value = current.Value,
Next = tempHead,
Previous = null,
};
tempHead.Previous = node;
tempHead = node;
current = current.Next;
}
}
}