/// <summary>
/// Returns the subnode containing the envelope.
/// Creates the node if
/// it does not already exist.
/// </summary>
/// <param name="searchInterval"></param>
public virtual Node GetNode(Interval searchInterval)
{
int subnodeIndex = GetSubnodeIndex(searchInterval, _centre);
// if index is -1 searchEnv is not contained in a subnode
if (subnodeIndex != -1)
{
// create the node if it does not exist
Node node = GetSubnode(subnodeIndex);
// recursively search the found/created node
return(node.GetNode(searchInterval));
}
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);
}