/// <summary>
/// Returns the smallest existing
/// node containing the envelope.
/// </summary>
/// <param name="searchInterval"></param>
public virtual NodeBase Find(Interval searchInterval)
{
int subnodeIndex = GetSubnodeIndex(searchInterval, _centre);
if (subnodeIndex == -1)
{
return(this);
}
if (Nodes[subnodeIndex] != null)
{
// query lies in subnode, so search it
Node node = Nodes[subnodeIndex];
return(node.Find(searchInterval));
}
// no existing subnode, so return this one anyway
return(this);
}
/// <summary>
/// Insert an item which is known to be contained in the tree rooted at
/// the given Node. Lower levels of the tree will be created
/// if necessary to hold the item.
/// </summary>
/// <param name="tree"></param>
/// <param name="itemInterval"></param>
/// <param name="item"></param>
private static void InsertContained(Node tree, Interval itemInterval, object item)
{
Assert.IsTrue(tree.Interval.Contains(itemInterval));
/*
* Do NOT create a new node for zero-area intervals - this would lead
* to infinite recursion. Instead, use a heuristic of simply returning
* the smallest existing node containing the query
*/
bool isZeroArea = IntervalSize.IsZeroWidth(itemInterval.Min, itemInterval.Max);
NodeBase node;
if (isZeroArea)
{
node = tree.Find(itemInterval);
}
else
{
node = tree.GetNode(itemInterval);
}
node.Add(item);
}