void RemoveLeaf(IntervalNode <TData> leaf)
{
Debug.Assert(leaf.IsLeaf);
var unbalancedNode = FindTopUnbalancedNode(leaf);
if (unbalancedNode != null)
{
RebuildUnderNodeWithoutLeaf(unbalancedNode, leaf);
UpdateParent(unbalancedNode);
}
else
{
//replace the parent with the sibling and update bounding boxes and counts
var parent = leaf.Parent;
if (parent == null)
{
Debug.Assert(rootNode == leaf);
rootNode = new IntervalNode <TData>();
}
else
{
TransferFromSibling(parent, leaf.IsLeftChild ? parent.Right : parent.Left);
UpdateParent(parent);
}
}
Debug.Assert(TreeIsCorrect(RootNode));
}
/// <summary>
/// returns all leaf nodes for which the interval was hit and the delegate is happy with the object
/// </summary>
/// <param name="intervalPar"></param>
/// <param name="hitTestAccept"></param>
/// <returns></returns>
public IEnumerable <TData> AllHitItems(Interval intervalPar, Func <TData, bool> hitTestAccept)
{
var stack = new Stack <IntervalNode <TData> >();
stack.Push(this);
while (stack.Count > 0)
{
IntervalNode <TData> node = stack.Pop();
if (node.Interval.Intersects(intervalPar))
{
if (node.IsLeaf)
{
if ((null == hitTestAccept) || hitTestAccept(node.UserData))
{
yield return(node.UserData);
}
}
else
{
stack.Push(node.left);
stack.Push(node.right);
}
}
}
}
internal static void CrossIntervalNodes <TA, TB>(IntervalNode <TA> a, IntervalNode <TB> b, Action <TA, TB> action)
{
if (!a.interval.Intersects(b.interval))
{
return;
}
if (a.Left == null) //a is a leat
{
if (b.Left == null) //b is a leaf
{
action(a.UserData, b.UserData);
}
else
{
CrossIntervalNodes(a, b.Left, action);
CrossIntervalNodes(a, b.Right, action);
}
}
else //a is not a leaf
{
if (b.Left != null)
{
CrossIntervalNodes(a.Left, b.Left, action);
CrossIntervalNodes(a.Left, b.Right, action);
CrossIntervalNodes(a.Right, b.Left, action);
CrossIntervalNodes(a.Right, b.Right, action);
}
else // b is a leaf
{
CrossIntervalNodes(a.Left, b, action);
CrossIntervalNodes(a.Right, b, action);
}
}
}
static void AddNodeToTreeRecursive(IntervalNode <TData> newNode, IntervalNode <TData> existingNode)
{
if (existingNode.IsLeaf)
{
existingNode.Left = new IntervalNode <TData>(existingNode.UserData, existingNode.Interval);
existingNode.Right = newNode;
existingNode.Count = 2;
existingNode.UserData = default(TData);
}
else
{
existingNode.Count++;
Interval leftBox;
Interval rightBox;
if (2 * existingNode.Left.Count < existingNode.Right.Count)
{
//keep the balance
AddNodeToTreeRecursive(newNode, existingNode.Left);
existingNode.Left.Interval = new Interval(existingNode.Left.Interval, newNode.Interval);
}
else if (2 * existingNode.Right.Count < existingNode.Left.Count)
{
//keep the balance
AddNodeToTreeRecursive(newNode, existingNode.Right);
existingNode.Right.Interval = new Interval(existingNode.Right.Interval, newNode.Interval);
}
else //decide basing on the boxes
{
leftBox = new Interval(existingNode.Left.Interval, newNode.Interval);
var delLeft = leftBox.Length - existingNode.Left.Interval.Length;
rightBox = new Interval(existingNode.Right.Interval, newNode.Interval);
var delRight = rightBox.Length - existingNode.Right.Interval.Length;
if (delLeft < delRight)
{
AddNodeToTreeRecursive(newNode, existingNode.Left);
existingNode.Left.Interval = leftBox;
}
else if (delLeft > delRight)
{
AddNodeToTreeRecursive(newNode, existingNode.Right);
existingNode.Right.Interval = rightBox;
}
else //the deltas are the same; add to the smallest
{
if (leftBox.Length < rightBox.Length)
{
AddNodeToTreeRecursive(newNode, existingNode.Left);
existingNode.Left.Interval = leftBox;
}
else
{
AddNodeToTreeRecursive(newNode, existingNode.Right);
existingNode.Right.Interval = rightBox;
}
}
}
}
existingNode.Interval = new Interval(existingNode.Left.Interval, existingNode.Right.Interval);
}
static void TransferFromSibling(IntervalNode <TData> parent, IntervalNode <TData> sibling)
{
parent.UserData = sibling.UserData;
parent.Left = sibling.Left;
parent.Right = sibling.Right;
parent.Count--;
parent.Interval = sibling.Interval;
}
static void UpdateParent(IntervalNode <TData> parent)
{
for (var node = parent.Parent; node != null; node = node.Parent)
{
node.Count--;
node.Interval = new Interval(node.Left.Interval, node.Right.Interval);
}
}
static bool HandleEqualityCheck <TA>(IntervalNode <TA> a, Func <TA, TA, bool> func)
{
if (a.Left == null)
{
return(false); //we don't do anything for two equal leafs
}
return(FindIntersectionWithProperty(a.Left, a.Left, func) ||
FindIntersectionWithProperty(a.Left, a.Right, func) || FindIntersectionWithProperty(a.Right, a.Right, func));
}
/// <summary>
/// we need to avoid calling action twice for the same pair
/// </summary>
/// <typeparam name="TA"></typeparam>
/// <param name="a"></param>
/// <param name="action"></param>
static void HandleEquality <TA>(IntervalNode <TA> a, Action <TA, TA> action)
{
if (a.Left == null)
{
return; //we don't do anything for two equal leafs
}
CrossIntervalNodes <TA>(a.Left, a.Left, action);
CrossIntervalNodes <TA>(a.Left, a.Right, action);
CrossIntervalNodes <TA>(a.Right, a.Right, action);
}
static IntervalNode <TData> FindTopUnbalancedNode(IntervalNode <TData> node)
{
for (var parent = node.Parent; parent != null; parent = parent.Parent)
{
if (!Balanced(parent))
{
return(parent);
}
}
return(null);
}
static void RebuildUnderNodeWithoutLeaf(IntervalNode <TData> nodeForRebuild, IntervalNode <TData> leaf)
{
Debug.Assert(leaf.IsLeaf);
Debug.Assert(!nodeForRebuild.IsLeaf);
var newNode =
IntervalNode <TData> .CreateIntervalNodeOnEnumeration(
nodeForRebuild.GetAllLeafNodes().Where(n => !(n.Equals(leaf))));
nodeForRebuild.Count = newNode.Count;
nodeForRebuild.Left = newNode.Left;
nodeForRebuild.Right = newNode.Right;
nodeForRebuild.Interval = new Interval(newNode.Left.interval, newNode.Right.interval);
}
static public void TraverseHierarchy(IntervalNode <TData> node, Action <IntervalNode <TData> > visitor)
{
ValidateArg.IsNotNull(node, "node");
ValidateArg.IsNotNull(visitor, "visitor");
visitor(node);
if (node.Left != null)
{
TraverseHierarchy(node.Left, visitor);
}
if (node.Right != null)
{
TraverseHierarchy(node.Right, visitor);
}
}
static bool TreeIsCorrect(IntervalNode <TData> node)
{
if (node == null)
{
return(true);
}
bool ret = node.Left != null && node.Right != null ||
node.Left == null && node.Right == null;
if (!ret)
{
return(false);
}
return(TreeIsCorrect(node.Left) && TreeIsCorrect(node.Right));
}
internal void Add(IntervalNode <TData> node)
{
if (rootNode == null)
{
rootNode = node;
}
else if (Count <= 2)
{
rootNode = IntervalNode <TData> .CreateIntervalNodeOnEnumeration(rootNode.GetAllLeafNodes().Concat(new[] { node }));
}
else
{
AddNodeToTreeRecursive(node, rootNode);
}
}
/// <summary>
///
/// </summary>
/// <returns></returns>
public IntervalNode <TData> Clone()
{
var ret = new IntervalNode <TData>(Count)
{
UserData = UserData, Interval = Interval
};
if (Left != null)
{
ret.Left = Left.Clone();
}
if (Right != null)
{
ret.Right = Right.Clone();
}
return(ret);
}
static public IntervalNode <TData> CreateIntervalNodeOnListOfNodes(IList <IntervalNode <TData> > nodes)
{
ValidateArg.IsNotNull(nodes, "nodes");
if (nodes.Count == 0)
{
return(null);
}
if (nodes.Count == 1)
{
return(nodes[0]);
}
//Finding the seeds
var b0 = nodes[0].Interval;
//the first seed
int seed0 = 1;
int seed1 = ChooseSeeds(nodes, ref b0, ref seed0);
//We have two seeds at hand. Build two groups.
var gr0 = new List <IntervalNode <TData> >();
var gr1 = new List <IntervalNode <TData> >();
gr0.Add(nodes[seed0]);
gr1.Add(nodes[seed1]);
var box0 = nodes[seed0].Interval;
var box1 = nodes[seed1].Interval;
//divide nodes on two groups
DivideNodes(nodes, seed0, seed1, gr0, gr1, ref box0, ref box1, GroupSplitThreshold);
var ret = new IntervalNode <TData>(nodes.Count)
{
Interval = new Interval(box0, box1),
Left = CreateIntervalNodeOnListOfNodes(gr0),
Right = CreateIntervalNodeOnListOfNodes(gr1)
};
return(ret);
}
static HitTestBehavior VisitTreeStatic(IntervalNode <TData> intervalNode, Func <TData, HitTestBehavior> hitTest, Interval hitInterval)
{
if (intervalNode.Interval.Intersects(hitInterval))
{
if (hitTest(intervalNode.UserData) == HitTestBehavior.Continue)
{
if (intervalNode.Left != null)
{
// If intervalNode.Left is not null, intervalNode.Right won't be either.
if (VisitTreeStatic(intervalNode.Left, hitTest, hitInterval) == HitTestBehavior.Continue &&
VisitTreeStatic(intervalNode.Right, hitTest, hitInterval) == HitTestBehavior.Continue)
{
return(HitTestBehavior.Continue);
}
return(HitTestBehavior.Stop);
}
return(HitTestBehavior.Continue);
}
return(HitTestBehavior.Stop);
}
return(HitTestBehavior.Continue);
}
public IEnumerable <IntervalNode <TData> > GetLeafIntervalNodesIntersectingInterval(Interval intervalPar)
{
var stack = new Stack <IntervalNode <TData> >();
stack.Push(this);
while (stack.Count > 0)
{
IntervalNode <TData> node = stack.Pop();
if (node.Interval.Intersects(intervalPar))
{
if (node.IsLeaf)
{
yield return(node);
}
else
{
stack.Push(node.left);
stack.Push(node.right);
}
}
}
}
internal static void CrossIntervalNodes <TA>(IntervalNode <TA> a, IntervalNode <TA> b, Action <TA, TA> action)
{
if (!a.interval.Intersects(b.interval))
{
return;
}
if (Equals(a, b))
{
HandleEquality(a, action);
}
else if (a.Left == null)
{
if (b.Left == null)
{
action(a.UserData, b.UserData);
}
else
{
CrossIntervalNodes <TA>(a, b.Left, action);
CrossIntervalNodes <TA>(a, b.Right, action);
}
}
else
{
if (b.Left != null)
{
CrossIntervalNodes <TA>(a.Left, b.Left, action);
CrossIntervalNodes <TA>(a.Left, b.Right, action);
CrossIntervalNodes <TA>(a.Right, b.Left, action);
CrossIntervalNodes <TA>(a.Right, b.Right, action);
}
else
{
CrossIntervalNodes <TA>(a.Left, b, action);
CrossIntervalNodes <TA>(a.Right, b, action);
}
}
}
/// <summary>
/// rebuild the whole tree
/// </summary>
public void Rebuild()
{
rootNode = IntervalNode <TData> .CreateIntervalNodeOnEnumeration(rootNode.GetAllLeafNodes());
}
/// <summary>
/// Create a query tree for a given root node
/// </summary>
/// <param name="rootNode"></param>
public IntervalRTree(IntervalNode <TData> rootNode)
{
this.rootNode = rootNode;
}
static bool Balanced(IntervalNode <TData> rectangleNode)
{
return(2 * rectangleNode.Left.Count >= rectangleNode.Right.Count &&
2 * rectangleNode.Right.Count >= rectangleNode.Left.Count);
}
/// <summary>
/// returns true if "property" holds for some pair
/// </summary>
/// <typeparam name="TA"></typeparam>
/// <param name="a"></param>
/// <param name="b"></param>
/// <param name="property"></param>
/// <returns></returns>
internal static bool FindIntersectionWithProperty <TA>(IntervalNode <TA> a, IntervalNode <TA> b, Func <TA, TA, bool> property)
{
if (!a.interval.Intersects(b.interval))
{
return(false);
}
if (Equals(a, b))
{
return(HandleEqualityCheck(a, property));
}
if (a.Left == null)
{
if (b.Left == null)
{
return(property(a.UserData, b.UserData));
}
if (FindIntersectionWithProperty(a, b.Left, property))
{
return(true);
}
if (FindIntersectionWithProperty(a, b.Right, property))
{
return(true);
}
}
else
{
if (b.Left != null)
{
if (FindIntersectionWithProperty(a.Left, b.Left, property))
{
return(true);
}
if (FindIntersectionWithProperty(a.Left, b.Right, property))
{
return(true);
}
if (FindIntersectionWithProperty(a.Right, b.Left, property))
{
return(true);
}
if (FindIntersectionWithProperty(a.Right, b.Right, property))
{
return(true);
}
}
else
{
if (FindIntersectionWithProperty(a.Left, b, property))
{
return(true);
}
if (FindIntersectionWithProperty(a.Right, b, property))
{
return(true);
}
}
}
return(false);
}
public IntervalRTree(IEnumerable <KeyValuePair <Interval, TData> > rectsAndData)
{
rootNode = IntervalNode <TData> .CreateIntervalNodeOnEnumeration(GetNodeRects(rectsAndData));
}