// ******************************************************************
private AvlNode <T> CopyTreeRecursive(AvlNode <T> source, AvlNode <T> copyParent)
{
if (source == null)
{
return(null);
}
AvlNode <T> copy = new AvlNode <T>();
copy.Parent = copyParent;
copy.Item = source.Item;
copy.Balance = source.Balance;
copy.Left = CopyTreeRecursive(source.Left, copy);
copy.Right = CopyTreeRecursive(source.Right, copy);
return(copy);
}
// ******************************************************************
public bool MoveNext()
{
if (_current == null)
{
_current = _avlTree.GetLastNode();
}
else
{
_current = _current.GetPreviousNode();
}
if (_current == null) // Should check for an empty tree too :-)
{
return(false);
}
return(true);
}
// ******************************************************************
/// <summary>
/// EO: New
/// </summary>
/// <param name="itemToDelete"></param>
/// <param name="child"></param>
private void ReplaceSafe(AvlNode <T> itemToDelete, AvlNode <T> child)
{
child.Parent = itemToDelete.Parent;
if (itemToDelete.Parent != null)
{
if (itemToDelete.Parent.Left == itemToDelete)
{
itemToDelete.Parent.Left = child;
}
else if (itemToDelete.Parent.Right == itemToDelete)
{
itemToDelete.Parent.Right = child;
}
}
else
{
_root = child;
}
}
// ******************************************************************
/// <summary>
/// WARNING THIS METHOD is modifying the node content.
/// This weird behavior cause side effect which could invalid any node previously referenced.
/// This method is used to remove node.
///
/// - THE BIG QUESTION is: Should I be able to obtain a ref on the node or not (like I added for remove nmode)???
/// - My answer is "NO" theoritically but in real life I say "YES" I want a ref in order to be more efficient in my context.
/// - I know that this could affect the Tree implementtion abstraction which could be prevented to change in the future
/// because I play with inner stuff but honestly, for performance here, I don't give a shit.
///
/// But could I replace node without touching the item? I should be able. It cost a little more thought :-)
/// </summary>
/// <param name="target"></param>
/// <param name="source"></param>
private static void Replace(AvlNode <T> target, AvlNode <T> source)
{
AvlNode <T> left = source.Left;
AvlNode <T> right = source.Right;
target.Balance = source.Balance;
target.Item = source.Item;
target.Left = left;
target.Right = right;
if (left != null)
{
left.Parent = target;
}
if (right != null)
{
right.Parent = target;
}
}
private void RecursiveEnsureNodeBalanceIsValid(AvlNode <T> node)
{
int leftHeight = GetMaxHeightRecursive(node.Left);
int rightHeight = GetMaxHeightRecursive(node.Right);
if (leftHeight == 0)
{
if (rightHeight == 0)
{
DumpIfNotTrue(node.Balance == 0);
}
else
{
DumpIfNotTrue(node.Balance == -1);
}
}
else
{
if (rightHeight == 0)
{
DumpIfNotTrue(node.Balance == 1);
}
else
{
DumpIfNotTrue(node.Balance == leftHeight - rightHeight);
}
}
if (node.Left != null)
{
RecursiveEnsureNodeBalanceIsValid(node.Left);
}
if (node.Right != null)
{
RecursiveEnsureNodeBalanceIsValid(node.Right);
}
}
// ******************************************************************
// No side effect on any node previously referenced, other than the deleted one and/or root if deleted node is the root
public virtual bool RemoveSafe(T item)
{
AvlNode <T> node = _root;
while (node != null)
{
if (_comparer.Compare(item, node.Item) < 0)
{
node = node.Left;
}
else if (_comparer.Compare(item, node.Item) > 0)
{
node = node.Right;
}
else
{
RemoveNodeSafe(node);
return(true);
}
}
return(false);
}
// ******************************************************************
public AvlNode <T> GetNode(T item)
{
AvlNode <T> node = _root;
while (node != null)
{
int compareResult = _comparer.Compare(item, node.Item);
if (compareResult < 0)
{
node = node.Left;
}
else if (compareResult > 0)
{
node = node.Right;
}
else
{
return(node);
}
}
return(null);
}
// ******************************************************************
public void Reset()
{
_current = null;
}
// ******************************************************************
// No side effect on any node previously referenced, other than the deleted one and/or root if deleted node is the root
public void RemoveNodeSafe(AvlNode <T> node)
{
_count--;
AvlNode <T> left = node.Left;
AvlNode <T> right = node.Right;
if (left == null)
{
if (right == null)
{
if (node == _root)
{
_root = null;
}
else
{
if (node.Parent.Left == node)
{
node.Parent.Left = null;
RemoveBalance(node.Parent, -1);
}
else if (node.Parent.Right == node)
{
node.Parent.Right = null;
RemoveBalance(node.Parent, 1);
}
else
{
DumpVisual2();
Debug.Assert(false); // Duplicate values ???
}
}
}
else
{
ReplaceSafe(node, right);
RemoveBalance(right, 0);
}
}
else if (right == null)
{
ReplaceSafe(node, left);
RemoveBalance(left, 0);
}
else
{
AvlNode <T> successor = right;
if (successor.Left == null)
{
AvlNode <T> parent = node.Parent;
successor.Parent = parent;
successor.Left = left;
successor.Balance = node.Balance;
left.Parent = successor;
if (node == _root)
{
_root = successor;
}
else
{
if (parent.Left == node)
{
parent.Left = successor;
}
else
{
parent.Right = successor;
}
}
RemoveBalance(successor, 1);
}
else
{
while (successor.Left != null)
{
successor = successor.Left;
}
AvlNode <T> parent = node.Parent;
AvlNode <T> successorParent = successor.Parent;
AvlNode <T> successorRight = successor.Right;
if (successorParent.Left == successor)
{
successorParent.Left = successorRight;
}
else
{
successorParent.Right = successorRight;
}
if (successorRight != null)
{
successorRight.Parent = successorParent;
}
successor.Parent = parent;
successor.Left = left;
successor.Balance = node.Balance;
successor.Right = right;
right.Parent = successor;
left.Parent = successor;
if (node == _root)
{
_root = successor;
}
else
{
if (parent.Left == node)
{
parent.Left = successor;
}
else
{
parent.Right = successor;
}
}
RemoveBalance(successorParent, -1);
}
}
}
// ******************************************************************
public void Clear()
{
_root = null;
_count = 0;
}
