/// <summary>
///
/// </summary>
/// <param name="searchBounds"></param>
/// <param name="node"></param>
/// <param name="item"></param>
/// <returns></returns>
private bool Remove(object searchBounds, AbstractNode node, object item)
{
// first try removing item from this node
bool found = RemoveItem(node, item);
if (found)
return true;
AbstractNode childToPrune = null;
// next try removing item from lower nodes
for (IEnumerator i = node.ChildBoundables.GetEnumerator(); i.MoveNext(); )
{
IBoundable childBoundable = (IBoundable)i.Current;
if (!IntersectsOp.Intersects(childBoundable.Bounds, searchBounds))
continue;
if (childBoundable is AbstractNode)
{
found = Remove(searchBounds, (AbstractNode)childBoundable, item);
// if found, record child for pruning and exit
if (found)
{
childToPrune = (AbstractNode)childBoundable;
break;
}
}
}
// prune child if possible
if (childToPrune != null)
if (childToPrune.ChildBoundables.Count == 0)
node.ChildBoundables.Remove(childToPrune);
return found;
}
/// <summary>
///
/// </summary>
/// <param name="level">-1 to get items.</param>
/// <param name="top"></param>
/// <param name="boundables"></param>
private static void BoundablesAtLevel(int level, AbstractNode top, ref IList boundables)
{
Assert.IsTrue(level > -2);
if (top.Level == level)
{
boundables.Add(top);
return;
}
for (IEnumerator i = top.ChildBoundables.GetEnumerator(); i.MoveNext(); )
{
IBoundable boundable = (IBoundable)i.Current;
if (boundable is AbstractNode)
BoundablesAtLevel(level, (AbstractNode)boundable, ref boundables);
else
{
Assert.IsTrue(boundable is ItemBoundable);
if (level == -1)
boundables.Add(boundable);
}
}
return;
}
/// <summary>
///
/// </summary>
/// <param name="node"></param>
/// <param name="item"></param>
/// <returns></returns>
private static bool RemoveItem(AbstractNode node, object item)
{
IBoundable childToRemove = null;
for (IEnumerator i = node.ChildBoundables.GetEnumerator(); i.MoveNext(); )
{
IBoundable childBoundable = (IBoundable)i.Current;
if (childBoundable is ItemBoundable)
if (((ItemBoundable)childBoundable).Item == item)
childToRemove = childBoundable;
}
if (childToRemove != null)
{
node.ChildBoundables.Remove(childToRemove);
return true;
}
return false;
}
/// <summary>
///
/// </summary>
/// <param name="searchBounds"></param>
/// <param name="node"></param>
/// <param name="visitor"></param>
private void Query(object searchBounds, AbstractNode node, IItemVisitor visitor)
{
foreach (object obj in node.ChildBoundables)
{
IBoundable childBoundable = (IBoundable)obj;
if (!IntersectsOp.Intersects(childBoundable.Bounds, searchBounds))
continue;
if (childBoundable is AbstractNode)
Query(searchBounds, (AbstractNode)childBoundable, visitor);
else if (childBoundable is ItemBoundable)
visitor.VisitItem(((ItemBoundable)childBoundable).Item);
else throw new ShouldNeverReachHereException();
}
}
/// <summary>
///
/// </summary>
/// <param name="node"></param>
/// <returns></returns>
protected virtual int GetDepth(AbstractNode node)
{
int maxChildDepth = 0;
for (IEnumerator i = node.ChildBoundables.GetEnumerator(); i.MoveNext(); )
{
IBoundable childBoundable = (IBoundable)i.Current;
if (childBoundable is AbstractNode)
{
int childDepth = GetDepth((AbstractNode)childBoundable);
if (childDepth > maxChildDepth)
maxChildDepth = childDepth;
}
}
return maxChildDepth + 1;
}
/// <summary>
///
/// </summary>
/// <param name="node"></param>
/// <returns></returns>
protected virtual int GetSize(AbstractNode node)
{
int size = 0;
for (IEnumerator i = node.ChildBoundables.GetEnumerator(); i.MoveNext(); )
{
IBoundable childBoundable = (IBoundable)i.Current;
if (childBoundable is AbstractNode)
size += GetSize((AbstractNode)childBoundable);
else if (childBoundable is ItemBoundable)
size += 1;
}
return size;
}
/// <summary>
/// Creates parent nodes, grandparent nodes, and so forth up to the root
/// node, for the data that has been inserted into the tree. Can only be
/// called once, and thus can be called only after all of the data has been
/// inserted into the tree.
/// </summary>
public virtual void Build()
{
Assert.IsTrue(!_built);
_root = (_itemBoundables.Count == 0) ? CreateNode(0) : CreateHigherLevels(_itemBoundables, -1);
_built = true;
}
