/// <summary>
/// Deletes element in i-th position.
/// </summary>
/// <param name="data">
/// Element to be deleted.
/// </param>
/// <param name="index">
/// Position index.
/// </param>
public BPlusTreeNode <T> Delete(T data, int index)
{
if (this.IsLeaf)
{
if (!this.IsHalf)
{
this.Values.RemoveAt(index);
return(this);
}
if (this._parent == null)
{
this.Values.RemoveAt(index);
return(this);
}
this.Values.Remove(data);
return(this.Merge());
}
// Find successor.
BPlusTreeNode <T> successorNode = null;
for (int i = 0; i < this.Values.Count; i++)
{
int result = this._comparer.Compare(this.Values[i], data);
if (result <= 0)
{
successorNode = (BPlusTreeNode <T>) this.Neighbors[i + 1];
}
}
while (successorNode.Neighbors != null)
{
successorNode = (BPlusTreeNode <T>)successorNode.Neighbors[0];
}
this.Values[index] = successorNode.Values[0];
return(successorNode.Delete(this.Values[index], 0));
}
/// <summary>
/// Deletes data from given node.
/// </summary>
/// <param name="node">
/// Node from which element will be removed.
/// </param>
/// <param name="data">
/// Element to be removed.
/// </param>
/// <returns>
/// </returns>
private BPlusTreeNode <T> Delete(BPlusTreeNode <T> node, T data)
{
while (node != null)
{
for (int i = 0; i < node.Values.Count; i++)
{
int result = this._comparer.Compare(node.Values[i], data);
if (result == 0)
{
return(node.Delete(data, i));
}
if (result > 0)
{
if (node.Neighbors == null)
{
return(null);
}
return(this.Delete((BPlusTreeNode <T>)node.Neighbors[i], data));
}
if (i + 1 == node.Values.Count)
{
if (node.Neighbors == null)
{
return(null);
}
return(this.Delete((BPlusTreeNode <T>)node.Neighbors[i + 1], data));
}
}
}
return(null);
}