/// <summary>
/// Splits a leaf node and adds the <paramref name="newEntry"/>
/// </summary>
/// <param name="node"></param>
/// <param name="newEntry"></param>
private void Split(MNode <int> node, MNodeEntry <int> newEntry)
{
var nodeIsRoot = node == this.Root;
MNode <int> parent = null;
var parentEntryIndex = -1;
if (!nodeIsRoot)
{
// keep reference to parent node
parent = node.ParentEntry.EnclosingNode;
parentEntryIndex = parent.Entries.IndexOf(node.ParentEntry);
//if we are not the root, the get the parent of the current node.
}
// Create local copy of entries
var entries = node.Entries.ToList();
entries.Add(newEntry);
var newNode = new MNode <int> {
Capacity = this.Capacity
};
var promotionResult = this.Promote(entries.ToArray(), node.IsInternalNode);
// TODO: Does not need to be an array
node.Entries = promotionResult.FirstPartition;
newNode.Entries = promotionResult.SecondPartition;
// Set child nodes of promotion objects
promotionResult.FirstPromotionObject.ChildNode = node;
promotionResult.SecondPromotionObject.ChildNode = newNode;
if (nodeIsRoot)
{
// if we are the root node, then create a new root and assign the promoted objects to them
var newRoot = new MNode <int> {
ParentEntry = null, Capacity = this.Capacity
};
newRoot.AddRange(
new List <MNodeEntry <int> >
{
promotionResult.FirstPromotionObject,
promotionResult.SecondPromotionObject
});
this.Root = newRoot;
}
else // we are not the root
{
// Set distance from parent
if (parent == this.Root)
{
promotionResult.FirstPromotionObject.DistanceFromParent = -1;
}
else
{
promotionResult.FirstPromotionObject.DistanceFromParent =
this.Metric(this.internalArray[promotionResult.FirstPromotionObject.Value], this.internalArray[parent.ParentEntry.Value]);
}
parent.SetEntryAtIndex(parentEntryIndex, promotionResult.FirstPromotionObject);
if (parent.IsFull)
{
this.Split(parent, promotionResult.SecondPromotionObject);
}
else
{
// Set distance from parent
if (parent == this.Root)
{
promotionResult.SecondPromotionObject.DistanceFromParent = -1;
}
else
{
promotionResult.SecondPromotionObject.DistanceFromParent =
this.Metric(this.internalArray[promotionResult.SecondPromotionObject.Value], this.internalArray[parent.ParentEntry.Value]);
}
parent.Add(promotionResult.SecondPromotionObject);
}
}
}
