private static IEnvelop SumChildBounds(RTreeNode node, int startIndex, int endIndex)
{
var retval = new Envelop();
for (var i = startIndex; i < endIndex; i++)
{
retval.Extend(node.Children[i].Envelope);
}
return(retval);
}
private void Remove(T item, Envelop envelope)
{
var node = Root;
var itemEnvelope = envelope;
var path = new Stack <RTreeNode>();
var indexes = new Stack <int>();
var i = 0;
var goingUp = false;
RTreeNode parent = null;
// depth-first iterative tree traversal
while (node != null || path.Count > 0)
{
if (node == null)
{
// go up
node = path.TryPop();
parent = path.TryPeek();
i = indexes.TryPop();
goingUp = true;
}
if (node != null && node.IsLeaf)
{
// check current node
var index = node.Children.FindIndex(n => Comparer.Equals(item, n.Data));
if (index != -1)
{
// item found, remove the item and condense tree upwards
node.Children.RemoveAt(index);
path.Push(node);
CondenseNodes(path.ToArray());
return;
}
}
if (!goingUp && !node.IsLeaf && node.Envelope.Contains(itemEnvelope))
{
// go down
path.Push(node);
indexes.Push(i);
i = 0;
parent = node;
node = node.Children[0];
}
else if (parent != null)
{
i++;
if (i == parent.Children.Count)
{
// end of list; will go up
node = null;
}
else
{
// go right
node = parent.Children[i];
goingUp = false;
}
}
else
{
node = null; // nothing found
}
}
}