// Split off and return the lower half in a new node
// We split off the lower half so that data about the upper key value of this node does not change
public InternalNode Split()
{
var nodeCount = upperKeyValues.Count / 2;
var splitKeys = new NodeKey[nodeCount];
upperKeyValues.CopyTo(splitKeys, 0, nodeCount);
var splitNode = new InternalNode();
foreach (var upperKey in splitKeys)
{
splitNode.AddNode(nodeIndices[upperKey], upperKey);
nodeIndices.Remove(upperKey);
upperKeyValues.Remove(upperKey);
}
return(splitNode);
}
// Split off and return the lower half in a new node
// We split off the lower half so that data about the upper key value of this node does not change
public LeafNode Split()
{
var keyCount = dataKeys.Count / 2;
var upperKeys = new NodeKey[keyCount];
dataKeys.CopyTo(upperKeys, 0, keyCount);
var splitNode = new LeafNode();
foreach (var upperKey in upperKeys)
{
splitNode.AddDataRow(upperKey, dataRows[upperKey]);
dataKeys.Remove(upperKey);
dataRows.Remove(upperKey);
}
return(splitNode);
}
protected override void Deserialize(byte[] data)
{
var index = 1; // First byte indicates the node's type
for (var i = 0; i < maxKeys; i++)
{
SharpDb.PageIndex pageIndex = Serializer.DeserializeInt(data, ref index);
NodeKey upperKey = Serializer.DeserializeInt(data, ref index);
if (upperKey != 0)
{
nodeIndices.Add(upperKey, pageIndex);
upperKeyValues.Add(upperKey);
}
else
{
nodeIndices.Add(int.MaxValue, pageIndex);
upperKeyValues.Add(int.MaxValue);
break;
}
}
}
public void AddDataRow(NodeKey key, Blob data)
{
bytesUsed += dataRowHeaderSize + data.ByteCount;
dataRows.Add(key, data);
dataKeys.Add(key);
}
public void AddDataRow(NodeKey key, byte[] data) => AddDataRow(key, new Blob(data));
public Blob GetDataRow(NodeKey key) => dataRows.ContainsKey(key) ? dataRows[key] : new Blob(new byte[0]);
public void InsertData(NodeKey key, byte[] data)
{
if (root is LeafNode)
{
InsertDataInLeafRoot(key, data);
return;
}
var nodeStack = new Stack <InternalNode>();
var currentNode = root;
// Descend the btree, recording the path from root to leaf
while (currentNode is InternalNode)
{
var currentInternalNode = (InternalNode)currentNode;
nodeStack.Push(currentInternalNode);
var childNodeIndex = currentInternalNode.GetPageIndexForKey(key);
currentNode = GetNode(childNodeIndex);
}
var leafNode = (LeafNode)currentNode;
if (leafNode.CanFitDataRow(data))
{
var largestKey = leafNode.GetLargestKey();
leafNode.AddDataRow(key, data);
}
else // Split the leaf node in two and find a place for the lower-ordered one
{
var largestKey = leafNode.GetLargestKey();
leafNode.AddDataRow(key, data);
var splitLeaf = leafNode.Split();
splitLeaf.PageIndex = pager.NewNodeIndex();
nodeCache.Add(splitLeaf.PageIndex, splitLeaf);
var currentInternalNode = nodeStack.Pop(); // Take the parent to the leaf nodes
if (!currentInternalNode.IsFull())
{
currentInternalNode.AddNode(splitLeaf.PageIndex, splitLeaf.GetLargestKey());
}
else // Keep splitting internal nodes and adding them to the parent until reaching one that can fit a new node without splitting
{
currentInternalNode.AddNode(splitLeaf.PageIndex, splitLeaf.GetLargestKey());
var splitInternalNode = currentInternalNode.Split();
splitInternalNode.PageIndex = pager.NewNodeIndex();
nodeCache.Add(splitInternalNode.PageIndex, splitInternalNode);
currentInternalNode = GetParentNode(nodeStack, currentInternalNode);
while (currentInternalNode.IsFull())
{
currentInternalNode.AddNode(splitInternalNode.PageIndex, splitInternalNode.GetLargestKey());
splitInternalNode = currentInternalNode.Split();
splitInternalNode.PageIndex = pager.NewNodeIndex();
nodeCache.Add(splitInternalNode.PageIndex, splitInternalNode);
currentInternalNode = GetParentNode(nodeStack, currentInternalNode);
}
currentInternalNode.AddNode(splitInternalNode.PageIndex, splitInternalNode.GetLargestKey());
}
}
}
public void ReplaceData(NodeKey key, byte[] data)
{
var leafNode = GetLeafNode(key);
leafNode.ReplaceDataRow(key, data);
}
public Blob GetData(NodeKey key)
{
var leafNode = GetLeafNode(key);
return(leafNode.GetDataRow(key));
}
public void AddNode(PageIndex pageIndex, NodeKey upperKey)
{
upperKeyValues.Add(upperKey);
nodeIndices.Add(upperKey, pageIndex);
}
public PageIndex GetPageIndexForKey(NodeKey key)
{
var upperRange = upperKeyValues.GetViewBetween(key, upperKeyValues.Max);
return(nodeIndices[upperRange.Min]);
}