protected void SplitLeaf(BPlusTreeNode <TKey, TValue> leafToSplit)
{
int pivotIndex = leafToSplit.Values.Count / 2;
BPlusTreeNodeSortedValues <TKey, TValue> leftValues = new BPlusTreeNodeSortedValues <TKey, TValue>();
BPlusTreeNodeSortedValues <TKey, TValue> rightValues = new BPlusTreeNodeSortedValues <TKey, TValue>();
leafToSplit.Values.CopyTo(leftValues, 0, pivotIndex + 1);
leafToSplit.Values.CopyTo(rightValues, pivotIndex + 1, leafToSplit.Values.Count);
BPlusTreeNode <TKey, TValue> leftNode = new BPlusTreeNode <TKey, TValue>(leftValues,
leafToSplit.ParentNode, null, null, leafToSplit.ParentTree, false);
BPlusTreeNode <TKey, TValue> rightNode = new BPlusTreeNode <TKey, TValue>(rightValues,
leafToSplit.ParentNode, null, null, leafToSplit.ParentTree, false);
leftNode.RightLeafNode = rightNode;
leftNode.LeftLeafNode = leafToSplit.LeftLeafNode;
rightNode.LeftLeafNode = leftNode;
rightNode.RightLeafNode = leafToSplit.RightLeafNode;
if (leafToSplit.LeftLeafNode != null)
{
leafToSplit.LeftLeafNode.RightLeafNode = leftNode;
}
if (leafToSplit.RightLeafNode != null)
{
leafToSplit.RightLeafNode.LeftLeafNode = rightNode;
}
if (!leafToSplit.IsRoot)
{
leafToSplit.ParentNode.Links.Remove(leafToSplit.Values.Keys.Max());
leafToSplit.ParentNode.Links.Add(rightNode.Values.Keys.Last(), rightNode);
leafToSplit.ParentNode.Links.Add(leftNode.Values.Keys.Last(), leftNode);
}
else
{
BPlusTreeNode <TKey, TValue> newRoot =
new BPlusTreeNode <TKey, TValue>(new BPlusTreeNodeSortedLinks <TKey, TValue>(), null, null, null,
leafToSplit.ParentTree, true);
leftNode.ParentNode = newRoot;
rightNode.ParentNode = newRoot;
newRoot.Links.Add(leftNode.Values.Keys.Last(), leftNode);
newRoot.Links.Add(rightNode.Values.Keys.Last(), rightNode);
Head = newRoot;
NodesCount++;
}
if (leftNode.ParentNode.KeysCount > MaxDegree)
{
Split(leftNode.ParentNode);
}
}
