/// <summary>
/// Helper method that deletes key from a node that contains it, be this
/// node a leaf node or an internal node.
/// </summary>
/// <param name="node">Node that contains the key.</param>
/// <param name="keyToDelete">Key to be deleted.</param>
/// <param name="keyIndexInNode">Index of key within the node.</param>
private void DeleteKeyFromNode(BTreeNode <TK, TP> node, TK keyToDelete, int keyIndexInNode)
{
// if leaf, just remove it from the list of entries (we're guaranteed to have
// at least "degree" # of entries, to BTree property is maintained
if (node.IsLeaf)
{
node.Entries.RemoveAt(keyIndexInNode);
return;
}
BTreeNode <TK, TP> predecessorChild = node.Children[keyIndexInNode];
if (predecessorChild.Entries.Count >= this.Degree)
{
BTreeEntry <TK, TP> predecessor = this.DeletePredecessor(predecessorChild);
node.Entries[keyIndexInNode] = predecessor;
}
else
{
BTreeNode <TK, TP> successorChild = node.Children[keyIndexInNode + 1];
if (successorChild.Entries.Count >= this.Degree)
{
BTreeEntry <TK, TP> successor = this.DeleteSuccessor(predecessorChild);
node.Entries[keyIndexInNode] = successor;
}
else
{
predecessorChild.Entries.Add(node.Entries[keyIndexInNode]);
predecessorChild.Entries.AddRange(successorChild.Entries);
predecessorChild.Children.AddRange(successorChild.Children);
node.Entries.RemoveAt(keyIndexInNode);
node.Children.RemoveAt(keyIndexInNode + 1);
this.DeleteInternal(predecessorChild, keyToDelete);
}
}
}
/// <summary></summary>
/// <param name="other"></param>
/// <returns></returns>
public bool Equals(BTreeEntry <TK, TP> other)
{
return(this.Key.Equals(other.Key) && this.Pointer.Equals(other.Pointer));
}
