public static BplusNode BinaryRoot(BplusNode LeftNode, string key, BplusNode RightNode, BplusTreeLong owner)
{
BplusNode newRoot = new BplusNode(owner, null, -1, false);
//newRoot.Clear(); // redundant
newRoot.ChildKeys[0] = key;
LeftNode.Reparent(newRoot, 0);
RightNode.Reparent(newRoot, 1);
// new root is stored elsewhere
return newRoot;
}
public BplusTreeLong(System.IO.Stream fromfile, int NodeSize, int KeyLength, long StartSeek, int CultureId)
{
this.cultureContext = new System.Globalization.CultureInfo(CultureId);
this.cmp = this.cultureContext.CompareInfo;
this.fromfile = fromfile;
this.NodeSize = NodeSize;
this.seekStart = StartSeek;
// add in key prefix overhead
this.KeyLength = KeyLength + BufferFile.SHORTSTORAGE;
this.rootSeek = NULLBUFFERNUMBER;
this.root = null;
this.freeHeadSeek = NULLBUFFERNUMBER;
this.SanityCheck();
}
/// <summary>
/// Create a new BplusNode and install in parent if parent is not null.
/// </summary>
/// <param name="owner">tree containing the node</param>
/// <param name="parent">parent node (if provided)</param>
/// <param name="indexInParent">location in parent if provided</param>
public BplusNode(BplusTreeLong owner, BplusNode parent, int indexInParent, bool isLeaf)
{
this.isLeaf = isLeaf;
this.owner = owner;
this.parent = parent;
this.Size = owner.NodeSize;
//this.isValid = true;
this.Dirty = true;
// this.ChildBufferNumbers = new long[this.Size+1];
// this.ChildKeys = new string[this.Size];
// this.MaterializedChildNodes = new BplusNode[this.Size+1];
this.Clear();
if (parent!=null && indexInParent>=0)
{
if (indexInParent>this.Size)
{
throw new BplusTreeException("parent index too large");
}
// key info, etc, set elsewhere
this.parent.MaterializedChildNodes[indexInParent] = this;
this.myBufferNumber = this.parent.ChildBufferNumbers[indexInParent];
this.indexInParent = indexInParent;
}
}
/// <summary>
/// Find the first key below atIndex, or if no such node traverse to the next key to the right.
/// If no such key exists, return nulls.
/// </summary>
/// <param name="atIndex">where to look in this node</param>
/// <param name="foundInLeaf">leaf where found</param>
/// <param name="keyFound">key value found</param>
void TraverseToFollowingKey(int atIndex, out BplusNode foundInLeaf, out string keyFound)
{
foundInLeaf = null;
keyFound = null;
bool lookInParent;
if (IsLeaf)
{
lookInParent = (atIndex>=m_size) || (m_childKeys[atIndex]==null);
}
else
{
lookInParent = (atIndex>m_size) ||
(atIndex>0 && m_childKeys[atIndex-1]==null);
}
if (lookInParent)
{
// if it's anywhere it's in the next child of parent
if (m_parent!=null && m_indexInParent>=0)
{
m_parent.TraverseToFollowingKey(m_indexInParent+1, out foundInLeaf, out keyFound);
return;
}
else
{
return; // no such following key
}
}
if (IsLeaf)
{
// leaf, we found it.
foundInLeaf = this;
keyFound = m_childKeys[atIndex];
}
else
{
// nonleaf, look in child (if there is one)
if (atIndex==0 || m_childKeys[atIndex-1]!=null)
{
var thechild = MaterializeNodeAtIndex(atIndex);
thechild.TraverseToFollowingKey(0, out foundInLeaf, out keyFound);
}
}
}
public void RemoveKey(string key)
{
if (this.root==null)
{
throw new BplusTreeKeyMissing("tree is empty: cannot delete");
}
bool MergeMe;
BplusNode theroot = this.root;
theroot.Delete(key, out MergeMe);
// if the root is not a leaf and contains only one child (no key), reroot
if (MergeMe && !this.root.isLeaf && this.root.SizeInUse()==0)
{
this.root = this.root.FirstChild();
this.rootSeek = this.root.makeRoot();
theroot.Free();
}
}
public void ForgetTerminalNode(BplusNode nonterminalNode)
{
if (!this.TerminalNodeToId.ContainsKey(nonterminalNode))
{
// silently ignore (?)
return;
}
int id = (int) this.TerminalNodeToId[nonterminalNode];
if (id == this.LowerTerminalNodeCount)
{
this.LowerTerminalNodeCount++;
}
this.IdToTerminalNode.Remove(id);
this.TerminalNodeToId.Remove(nonterminalNode);
}
public long this[string key]
{
get
{
return MyGetKey(key, true);
}
set
{
if (!BplusNode.KeyOK(key, this))
{
throw new BplusTreeBadKeyValue("null or too large key cannot be inserted into tree: "+key);
}
bool rootinit = false;
if (this.root==null)
{
// allocate root
this.root = new BplusNode(this, null, -1, true);
rootinit = true;
//this.rootSeek = root.DumpToFreshBuffer();
}
// insert into root...
string splitString;
BplusNode splitNode;
root.Insert(key, value, out splitString, out splitNode);
if (splitNode!=null)
{
// split of root: make a new root.
rootinit = true;
BplusNode oldRoot = this.root;
this.root = BplusNode.BinaryRoot(oldRoot, splitString, splitNode, this);
}
if (rootinit)
{
this.rootSeek = root.DumpToFreshBuffer();
}
// check size in memory
this.ShrinkFootprint();
}
}
void Reparent(BplusNode newParent, int ParentIndex)
{
// keys and existing parent structure must be updated elsewhere.
this.parent = newParent;
this.indexInParent = ParentIndex;
newParent.ChildBufferNumbers[ParentIndex] = this.myBufferNumber;
newParent.MaterializedChildNodes[ParentIndex] = this;
// parent is no longer terminal
this.owner.ForgetTerminalNode(parent);
}
/// <summary>
/// insert key/position entry in self
/// </summary>
/// <param name="key">Key to associate with the leaf</param>
/// <param name="position">position associated with key in external structur</param>
/// <param name="splitString">if not null then the smallest key in the new split leaf</param>
/// <param name="splitNode">if not null then the node was split and this is the leaf to the right.</param>
/// <returns>null unless the smallest key under this node has changed, in which case it returns the smallest key.</returns>
public string Insert(string key, long position, out string splitString, out BplusNode splitNode)
{
if (IsLeaf)
{
return InsertLeaf(key, position, out splitString, out splitNode);
}
splitString = null;
splitNode = null;
var insertposition = FindAtOrNextPosition(key, false);
var insertBufferNumber = m_childBufferNumbers[insertposition];
if (insertBufferNumber==BplusTreeLong.Nullbuffernumber)
{
throw new BplusTreeException("key not followed by buffer number in non-leaf");
}
// insert in subtree
var insertChild = MaterializeNodeAtIndex(insertposition);
BplusNode childSplit;
string childSplitString;
var childInsert = insertChild.Insert(key, position, out childSplitString, out childSplit);
// if there was a split the node must expand
if (childSplit!=null)
{
// insert the child
Soil(); // redundant -- a child will have a change so this node will need to be copied
var newChildPosition = insertposition+1;
var dosplit = false;
// if there is no free space we must do a split
if (m_childBufferNumbers[m_size]!=BplusTreeLong.Nullbuffernumber)
{
dosplit = true;
PrepareForSplit();
}
// bubble over the current values to make space for new child
for (var i=m_childKeys.Length-2; i>=newChildPosition-1; i--)
{
var i1 = i+1;
var i2 = i1+1;
m_childKeys[i1] = m_childKeys[i];
m_childBufferNumbers[i2] = m_childBufferNumbers[i1];
var childNode = m_materializedChildNodes[i2] = m_materializedChildNodes[i1];
}
// record the new child
m_childKeys[newChildPosition-1] = childSplitString;
//this.MaterializedChildNodes[newChildPosition] = childSplit;
//this.ChildBufferNumbers[newChildPosition] = childSplit.myBufferNumber;
childSplit.Reparent(this, newChildPosition);
// split, if needed
if (dosplit)
{
var splitpoint = m_materializedChildNodes.Length/2-1;
splitString = m_childKeys[splitpoint];
splitNode = new BplusNode(m_owner, m_parent, -1, IsLeaf);
// make copy of expanded node structure
var materialized = m_materializedChildNodes;
var buffernumbers = m_childBufferNumbers;
var keys = m_childKeys;
// repair the expanded node
m_childKeys = new string[m_size];
m_materializedChildNodes = new BplusNode[m_size+1];
m_childBufferNumbers = new long[m_size+1];
Clear();
Array.Copy(materialized, 0, m_materializedChildNodes, 0, splitpoint+1);
Array.Copy(buffernumbers, 0, m_childBufferNumbers, 0, splitpoint+1);
Array.Copy(keys, 0, m_childKeys, 0, splitpoint);
// initialize the new node
splitNode.Clear(); // redundant.
var remainingKeys = m_size-splitpoint;
Array.Copy(materialized, splitpoint+1, splitNode.m_materializedChildNodes, 0, remainingKeys+1);
Array.Copy(buffernumbers, splitpoint+1, splitNode.m_childBufferNumbers, 0, remainingKeys+1);
Array.Copy(keys, splitpoint+1, splitNode.m_childKeys, 0, remainingKeys);
// fix pointers in materialized children of splitnode
splitNode.ReParentAllChildren();
// store the new node
splitNode.DumpToFreshBuffer();
splitNode.CheckIfTerminal();
splitNode.Soil();
CheckIfTerminal();
}
// fix pointers in children
ReParentAllChildren();
}
if (insertposition==0)
{
// the smallest key may have changed
return childInsert;
}
return null; // no change in smallest key
}
public void RemoveKey(string key)
{
if (m_root==null)
{
throw new BplusTreeKeyMissing("tree is empty: cannot delete");
}
bool mergeMe;
var theroot = m_root;
theroot.Delete(key, out mergeMe);
// if the root is not a leaf and contains only one child (no key), reroot
if (mergeMe && !m_root.IsLeaf && m_root.SizeInUse()==0)
{
m_root = m_root.FirstChild();
m_rootSeek = m_root.MakeRoot();
theroot.Free();
}
}
public void RecordTerminalNode(BplusNode terminalNode)
{
if (terminalNode==m_root)
{
return; // never record the root node
}
if (m_terminalNodeToId.ContainsKey(terminalNode) )
{
return; // don't record it again
}
var id = m_terminalNodeCount;
m_terminalNodeCount++;
m_terminalNodeToId[terminalNode] = id;
m_idToTerminalNode[id] = terminalNode;
}
public void ForgetTerminalNode(BplusNode nonterminalNode)
{
if (!m_terminalNodeToId.ContainsKey(nonterminalNode))
{
// silently ignore (?)
return;
}
var id = (int) m_terminalNodeToId[nonterminalNode];
if (id == m_lowerTerminalNodeCount)
{
m_lowerTerminalNodeCount++;
}
m_idToTerminalNode.Remove(id);
m_terminalNodeToId.Remove(nonterminalNode);
}
/// <summary>
/// Forget all changes since last commit
/// </summary>
public void Abort()
{
// deallocate allocated blocks
var toFree = new ArrayList();
foreach (DictionaryEntry d in FreeBuffersOnAbort)
{
toFree.Add(d.Key);
}
toFree.Sort();
toFree.Reverse();
foreach (var thing in toFree)
{
var buffernumber = (long) thing;
DeallocateBuffer(buffernumber);
}
var freehead = m_freeHeadSeek;
// reread the header (except for freelist head)
ReadHeader();
// restore the root
if (m_rootSeek==Nullbuffernumber)
{
m_root = null; // nothing was committed
}
else
{
m_root.LoadFromBuffer(m_rootSeek);
}
ResetBookkeeping();
m_freeHeadSeek = freehead;
SetHeader(); // store new freelist head
Fromfile.Flush();
}
public long this[string key]
{
get
{
long valueFound;
var test = ContainsKey(key, out valueFound);
if (!test)
{
throw new BplusTreeKeyMissing("no such key found: "+key);
}
return valueFound;
}
set
{
if (!BplusNode.KeyOK(key, this))
{
throw new BplusTreeBadKeyValue("null or too large key cannot be inserted into tree: "+key);
}
var rootinit = false;
if (m_root==null)
{
// allocate root
m_root = new BplusNode(this, null, -1, true);
rootinit = true;
//this.rootSeek = root.DumpToFreshBuffer();
}
// insert into root...
string splitString;
BplusNode splitNode;
m_root.Insert(key, value, out splitString, out splitNode);
if (splitNode!=null)
{
// split of root: make a new root.
rootinit = true;
var oldRoot = m_root;
m_root = BplusNode.BinaryRoot(oldRoot, splitString, splitNode, this);
}
if (rootinit)
{
m_rootSeek = m_root.DumpToFreshBuffer();
}
// check size in memory
ShrinkFootprint();
}
}
public BplusTreeLong(Stream fromfile, int nodeSize, int keyLength, long startSeek, int cultureId)
{
CultureContext = new CultureInfo(cultureId);
m_cmp = CultureContext.CompareInfo;
Fromfile = fromfile;
NodeSize = nodeSize;
SeekStart = startSeek;
// add in key prefix overhead
KeyLength = keyLength + BufferFile.Shortstorage;
m_rootSeek = Nullbuffernumber;
m_root = null;
m_freeHeadSeek = Nullbuffernumber;
SanityCheck();
}
BplusNode MaterializeNodeAtIndex(int myposition)
{
if (this.isLeaf)
{
throw new BplusTreeException("cannot materialize child for leaf");
}
long childBufferNumber = this.ChildBufferNumbers[myposition];
if (childBufferNumber==BplusTreeLong.NULLBUFFERNUMBER)
{
throw new BplusTreeException("can't search null subtree at position "+myposition+" in "+this.myBufferNumber);
}
// is it already materialized?
BplusNode result = this.MaterializedChildNodes[myposition];
if (result!=null)
{
return result;
}
// otherwise read it in...
result = new BplusNode(this.owner, this, myposition, true); // dummy isLeaf value
result.LoadFromBuffer(childBufferNumber);
this.MaterializedChildNodes[myposition] = result;
// no longer terminal
this.owner.ForgetTerminalNode(this);
return result;
}
/// <summary>
/// Grow to this.size+1 in preparation for insertion and split
/// </summary>
void PrepareForSplit()
{
int supersize = this.Size+1;
long[] positions = new long[supersize+1];
string[] keys = new string[supersize];
BplusNode[] materialized = new BplusNode[supersize+1];
Array.Copy(this.ChildBufferNumbers, 0, positions, 0, this.Size+1);
positions[this.Size+1] = BplusTreeLong.NULLBUFFERNUMBER;
Array.Copy(this.ChildKeys, 0, keys, 0, this.Size);
keys[this.Size] = null;
Array.Copy(this.MaterializedChildNodes, 0, materialized, 0, this.Size+1);
materialized[this.Size+1] = null;
this.ChildBufferNumbers = positions;
this.ChildKeys = keys;
this.MaterializedChildNodes = materialized;
}
/// <summary>
/// insert key/position entry in self (as leaf)
/// </summary>
/// <param name="key">Key to associate with the leaf</param>
/// <param name="position">position associated with key in external structure</param>
/// <param name="splitString">if not null then the smallest key in the new split leaf</param>
/// <param name="splitNode">if not null then the node was split and this is the leaf to the right.</param>
/// <returns>smallest key value in keys, or null if no change</returns>
public string InsertLeaf(string key, long position, out string splitString, out BplusNode splitNode)
{
splitString = null;
splitNode = null;
var dosplit = false;
if (!IsLeaf)
{
throw new BplusTreeException("bad call to InsertLeaf: this is not a leaf");
}
Soil();
var insertposition = FindAtOrNextPosition(key, false);
if (insertposition>=m_size)
{
//throw new BplusTreeException("key too big and leaf is full");
dosplit = true;
PrepareForSplit();
}
else
{
// if it's already there then change the value at the current location (duplicate entries not supported).
if (m_childKeys[insertposition]==null || m_owner.Compare(m_childKeys[insertposition], key)==0) // this.ChildKeys[insertposition].Equals(key)
{
m_childBufferNumbers[insertposition] = position;
m_childKeys[insertposition] = key;
if (insertposition==0)
{
return key;
}
else
{
return null;
}
}
}
// check for a null position
var nullindex = insertposition;
while (nullindex<m_childKeys.Length && m_childKeys[nullindex]!=null)
{
nullindex++;
}
if (nullindex>=m_childKeys.Length)
{
if (dosplit)
{
throw new BplusTreeException("can't split twice!!");
}
//throw new BplusTreeException("no space in leaf");
dosplit = true;
PrepareForSplit();
}
// bubble in the new info XXXX THIS SHOULD BUBBLE BACKWARDS
var nextkey = m_childKeys[insertposition];
var nextposition = m_childBufferNumbers[insertposition];
m_childKeys[insertposition] = key;
m_childBufferNumbers[insertposition] = position;
while (nextkey!=null)
{
key = nextkey;
position = nextposition;
insertposition++;
nextkey = m_childKeys[insertposition];
nextposition = m_childBufferNumbers[insertposition];
m_childKeys[insertposition] = key;
m_childBufferNumbers[insertposition] = position;
}
// split if needed
if (dosplit)
{
var splitpoint = m_childKeys.Length/2;
var splitlength = m_childKeys.Length - splitpoint;
splitNode = new BplusNode(m_owner, m_parent, -1, IsLeaf);
// copy the split info into the splitNode
Array.Copy(m_childBufferNumbers, splitpoint, splitNode.m_childBufferNumbers, 0, splitlength);
Array.Copy(m_childKeys, splitpoint, splitNode.m_childKeys, 0, splitlength);
Array.Copy(m_materializedChildNodes, splitpoint, splitNode.m_materializedChildNodes, 0, splitlength);
splitString = splitNode.m_childKeys[0];
// archive the new node
splitNode.DumpToFreshBuffer();
// store the node data temporarily
var buffernumbers = m_childBufferNumbers;
var keys = m_childKeys;
var nodes = m_materializedChildNodes;
// repair current node, copy in the other part of the split
m_childBufferNumbers = new long[m_size+1];
m_childKeys = new string[m_size];
m_materializedChildNodes = new BplusNode[m_size+1];
Array.Copy(buffernumbers, 0, m_childBufferNumbers, 0, splitpoint);
Array.Copy(keys, 0, m_childKeys, 0, splitpoint);
Array.Copy(nodes, 0, m_materializedChildNodes, 0, splitpoint);
for (var i=splitpoint; i<m_childKeys.Length; i++)
{
m_childKeys[i] = null;
m_childBufferNumbers[i] = BplusTreeLong.Nullbuffernumber;
m_materializedChildNodes[i] = null;
}
// store the new node
//splitNode.DumpToFreshBuffer();
m_owner.RecordTerminalNode(splitNode);
splitNode.Soil();
}
//return this.ChildKeys[0];
if (insertposition==0)
{
return key; // smallest key changed.
}
else
{
return null; // no change in smallest key
}
}
/// <summary>
/// Find the first key below atIndex, or if no such node traverse to the next key to the right.
/// If no such key exists, return nulls.
/// </summary>
/// <param name="atIndex">where to look in this node</param>
/// <param name="FoundInLeaf">leaf where found</param>
/// <param name="KeyFound">key value found</param>
void TraverseToFollowingKey(int atIndex, out BplusNode FoundInLeaf, out string KeyFound)
{
FoundInLeaf = null;
KeyFound = null;
bool LookInParent = false;
if (this.isLeaf)
{
LookInParent = (atIndex>=this.Size) || (this.ChildKeys[atIndex]==null);
}
else
{
LookInParent = (atIndex>this.Size) ||
(atIndex>0 && this.ChildKeys[atIndex-1]==null);
}
if (LookInParent)
{
// if it's anywhere it's in the next child of parent
if (this.parent!=null && this.indexInParent>=0)
{
this.parent.TraverseToFollowingKey(this.indexInParent+1, out FoundInLeaf, out KeyFound);
return;
}
else
{
return; // no such following key
}
}
if (this.isLeaf)
{
// leaf, we found it.
FoundInLeaf = this;
KeyFound = this.ChildKeys[atIndex];
return;
}
else
{
// nonleaf, look in child (if there is one)
if (atIndex==0 || this.ChildKeys[atIndex-1]!=null)
{
BplusNode thechild = this.MaterializeNodeAtIndex(atIndex);
thechild.TraverseToFollowingKey(0, out FoundInLeaf, out KeyFound);
}
}
}
public long makeRoot()
{
this.parent = null;
this.indexInParent = -1;
if (this.myBufferNumber==BplusTreeLong.NULLBUFFERNUMBER)
{
throw new BplusTreeException("no root seek allocated to new root");
}
return this.myBufferNumber;
}
/// <summary>
/// Forget all changes since last commit
/// </summary>
public void Abort()
{
// deallocate allocated blocks
ArrayList toFree = new ArrayList();
foreach (DictionaryEntry d in this.FreeBuffersOnAbort)
{
toFree.Add(d.Key);
}
toFree.Sort();
toFree.Reverse();
foreach (object thing in toFree)
{
long buffernumber = (long) thing;
this.deallocateBuffer(buffernumber);
}
long freehead = this.freeHeadSeek;
// reread the header (except for freelist head)
this.readHeader();
// restore the root
if (this.rootSeek==NULLBUFFERNUMBER)
{
this.root = null; // nothing was committed
}
else
{
this.root.LoadFromBuffer(this.rootSeek);
}
this.ResetBookkeeping();
this.freeHeadSeek = freehead;
this.setHeader(); // store new freelist head
this.fromfile.Flush();
}
public static void Merge(BplusNode left, string KeyBetween, BplusNode right, out string rightLeastKey,
out bool DeleteRight)
{
//System.Diagnostics.Debug.WriteLine("\r\n<br> merging "+right.myBufferNumber+" ("+KeyBetween+") "+left.myBufferNumber);
//System.Diagnostics.Debug.WriteLine(left.owner.toHtml());
rightLeastKey = null; // only if DeleteRight
if (left.isLeaf || right.isLeaf)
{
if (!(left.isLeaf&&right.isLeaf))
{
throw new BplusTreeException("can't merge leaf with non-leaf");
}
MergeLeaves(left, right, out DeleteRight);
rightLeastKey = right.ChildKeys[0];
return;
}
// merge non-leaves
DeleteRight = false;
string[] allkeys = new string[left.Size*2+1];
long[] allseeks = new long[left.Size*2+2];
BplusNode[] allMaterialized = new BplusNode[left.Size*2+2];
if (left.ChildBufferNumbers[0]==BplusTreeLong.NULLBUFFERNUMBER ||
right.ChildBufferNumbers[0]==BplusTreeLong.NULLBUFFERNUMBER)
{
throw new BplusTreeException("cannot merge empty non-leaf with non-leaf");
}
int index = 0;
allseeks[0] = left.ChildBufferNumbers[0];
allMaterialized[0] = left.MaterializedChildNodes[0];
for (int i=0; i<left.Size; i++)
{
if (left.ChildKeys[i]==null)
{
break;
}
allkeys[index] = left.ChildKeys[i];
allseeks[index+1] = left.ChildBufferNumbers[i+1];
allMaterialized[index+1] = left.MaterializedChildNodes[i+1];
index++;
}
allkeys[index] = KeyBetween;
index++;
allseeks[index] = right.ChildBufferNumbers[0];
allMaterialized[index] = right.MaterializedChildNodes[0];
int rightcount = 0;
for (int i=0; i<right.Size; i++)
{
if (right.ChildKeys[i]==null)
{
break;
}
allkeys[index] = right.ChildKeys[i];
allseeks[index+1] = right.ChildBufferNumbers[i+1];
allMaterialized[index+1] = right.MaterializedChildNodes[i+1];
index++;
rightcount++;
}
if (index<=left.Size)
{
// it will all fit in one node
//System.Diagnostics.Debug.WriteLine("deciding to forget "+right.myBufferNumber+" into "+left.myBufferNumber);
DeleteRight = true;
for (int i=0; i<index; i++)
{
left.ChildKeys[i] = allkeys[i];
left.ChildBufferNumbers[i] = allseeks[i];
left.MaterializedChildNodes[i] = allMaterialized[i];
}
left.ChildBufferNumbers[index] = allseeks[index];
left.MaterializedChildNodes[index] = allMaterialized[index];
left.reParentAllChildren();
left.Soil();
right.Free();
return;
}
// otherwise split the content between the nodes
left.Clear();
right.Clear();
left.Soil();
right.Soil();
int leftcontent = index/2;
int rightcontent = index-leftcontent-1;
rightLeastKey = allkeys[leftcontent];
int outputindex = 0;
for (int i=0; i<leftcontent; i++)
{
left.ChildKeys[i] = allkeys[outputindex];
left.ChildBufferNumbers[i] = allseeks[outputindex];
left.MaterializedChildNodes[i] = allMaterialized[outputindex];
outputindex++;
}
rightLeastKey = allkeys[outputindex];
left.ChildBufferNumbers[outputindex] = allseeks[outputindex];
left.MaterializedChildNodes[outputindex] = allMaterialized[outputindex];
outputindex++;
rightcount = 0;
for (int i=0; i<rightcontent; i++)
{
right.ChildKeys[i] = allkeys[outputindex];
right.ChildBufferNumbers[i] = allseeks[outputindex];
right.MaterializedChildNodes[i] = allMaterialized[outputindex];
outputindex++;
rightcount++;
}
right.ChildBufferNumbers[rightcount] = allseeks[outputindex];
right.MaterializedChildNodes[rightcount] = allMaterialized[outputindex];
left.reParentAllChildren();
right.reParentAllChildren();
}
public void RecordTerminalNode(BplusNode terminalNode)
{
if (terminalNode==this.root)
{
return; // never record the root node
}
if (this.TerminalNodeToId.ContainsKey(terminalNode) )
{
return; // don't record it again
}
int id = this.TerminalNodeCount;
this.TerminalNodeCount++;
this.TerminalNodeToId[terminalNode] = id;
this.IdToTerminalNode[id] = terminalNode;
}
public void SerializationCheck()
{
BplusNode A = new BplusNode(this.owner, null, -1, false);
for (int i=0; i<this.Size; i++)
{
long j = i*((long)0xf0f0f0f0f0f0f01);
A.ChildBufferNumbers[i] = j;
A.ChildKeys[i] = "k"+i;
}
A.ChildBufferNumbers[this.Size] = 7;
A.TestRebuffer();
A.isLeaf = true;
for (int i=0; i<this.Size; i++)
{
long j = -i*((long)0x3e3e3e3e3e3e666);
A.ChildBufferNumbers[i] = j;
A.ChildKeys[i] = "key"+i;
}
A.ChildBufferNumbers[this.Size] = -9097;
A.TestRebuffer();
}
public static void MergeLeaves(BplusNode left, BplusNode right, out bool DeleteRight)
{
DeleteRight = false;
string[] allkeys = new string[left.Size*2];
long[] allseeks = new long[left.Size*2];
int index = 0;
for (int i=0; i<left.Size; i++)
{
if (left.ChildKeys[i]==null)
{
break;
}
allkeys[index] = left.ChildKeys[i];
allseeks[index] = left.ChildBufferNumbers[i];
index++;
}
for (int i=0; i<right.Size; i++)
{
if (right.ChildKeys[i]==null)
{
break;
}
allkeys[index] = right.ChildKeys[i];
allseeks[index] = right.ChildBufferNumbers[i];
index++;
}
if (index<=left.Size)
{
left.Clear();
DeleteRight = true;
for (int i=0; i<index; i++)
{
left.ChildKeys[i] = allkeys[i];
left.ChildBufferNumbers[i] = allseeks[i];
}
right.Free();
left.Soil();
return;
}
left.Clear();
right.Clear();
left.Soil();
right.Soil();
int rightcontent = index/2;
int leftcontent = index - rightcontent;
int newindex = 0;
for (int i=0; i<leftcontent; i++)
{
left.ChildKeys[i] = allkeys[newindex];
left.ChildBufferNumbers[i] = allseeks[newindex];
newindex++;
}
for (int i=0; i<rightcontent; i++)
{
right.ChildKeys[i] = allkeys[newindex];
right.ChildBufferNumbers[i] = allseeks[newindex];
newindex++;
}
}
void Destroy()
{
// make sure the structure is useless, it should no longer be used.
this.owner = null;
this.parent = null;
this.Size = -100;
this.ChildBufferNumbers = null;
this.ChildKeys = null;
this.MaterializedChildNodes = null;
this.myBufferNumber = BplusTreeLong.NULLBUFFERNUMBER;
this.indexInParent = -100;
this.Dirty = false;
}
/// <summary>
/// insert key/position entry in self
/// </summary>
/// <param name="key">Key to associate with the leaf</param>
/// <param name="position">position associated with key in external structur</param>
/// <param name="splitString">if not null then the smallest key in the new split leaf</param>
/// <param name="splitNode">if not null then the node was split and this is the leaf to the right.</param>
/// <returns>null unless the smallest key under this node has changed, in which case it returns the smallest key.</returns>
public string Insert(string key, long position, out string splitString, out BplusNode splitNode)
{
if (this.isLeaf)
{
return this.InsertLeaf(key, position, out splitString, out splitNode);
}
splitString = null;
splitNode = null;
int insertposition = this.FindAtOrNextPosition(key, false, true);
long insertBufferNumber = this.ChildBufferNumbers[insertposition];
if (insertBufferNumber==BplusTreeLong.NULLBUFFERNUMBER)
{
throw new BplusTreeException("key not followed by buffer number in non-leaf");
}
// insert in subtree
BplusNode InsertChild = this.MaterializeNodeAtIndex(insertposition);
BplusNode childSplit;
string childSplitString;
string childInsert = InsertChild.Insert(key, position, out childSplitString, out childSplit);
// if there was a split the node must expand
if (childSplit!=null)
{
// insert the child
this.Soil(); // redundant -- a child will have a change so this node will need to be copied
int newChildPosition = insertposition+1;
bool dosplit = false;
// if there is no free space we must do a split
if (this.ChildBufferNumbers[this.Size]!=BplusTreeLong.NULLBUFFERNUMBER)
{
dosplit = true;
this.PrepareForSplit();
}
// bubble over the current values to make space for new child
for (int i=this.ChildKeys.Length-2; i>=newChildPosition-1; i--)
{
int i1 = i+1;
int i2 = i1+1;
this.ChildKeys[i1] = this.ChildKeys[i];
this.ChildBufferNumbers[i2] = this.ChildBufferNumbers[i1];
BplusNode childNode = this.MaterializedChildNodes[i2] = this.MaterializedChildNodes[i1];
}
// record the new child
this.ChildKeys[newChildPosition-1] = childSplitString;
//this.MaterializedChildNodes[newChildPosition] = childSplit;
//this.ChildBufferNumbers[newChildPosition] = childSplit.myBufferNumber;
childSplit.Reparent(this, newChildPosition);
// split, if needed
if (dosplit)
{
int splitpoint = this.MaterializedChildNodes.Length/2-1;
splitString = this.ChildKeys[splitpoint];
splitNode = new BplusNode(this.owner, this.parent, -1, this.isLeaf);
// make copy of expanded node structure
BplusNode[] materialized = this.MaterializedChildNodes;
long[] buffernumbers = this.ChildBufferNumbers;
string[] keys = this.ChildKeys;
// repair the expanded node
this.ChildKeys = new string[this.Size];
this.MaterializedChildNodes = new BplusNode[this.Size+1];
this.ChildBufferNumbers = new long[this.Size+1];
this.Clear();
Array.Copy(materialized, 0, this.MaterializedChildNodes, 0, splitpoint+1);
Array.Copy(buffernumbers, 0, this.ChildBufferNumbers, 0, splitpoint+1);
Array.Copy(keys, 0, this.ChildKeys, 0, splitpoint);
// initialize the new node
splitNode.Clear(); // redundant.
int remainingKeys = this.Size-splitpoint;
Array.Copy(materialized, splitpoint+1, splitNode.MaterializedChildNodes, 0, remainingKeys+1);
Array.Copy(buffernumbers, splitpoint+1, splitNode.ChildBufferNumbers, 0, remainingKeys+1);
Array.Copy(keys, splitpoint+1, splitNode.ChildKeys, 0, remainingKeys);
// fix pointers in materialized children of splitnode
splitNode.reParentAllChildren();
// store the new node
splitNode.DumpToFreshBuffer();
splitNode.CheckIfTerminal();
splitNode.Soil();
this.CheckIfTerminal();
}
// fix pointers in children
this.reParentAllChildren();
}
if (insertposition==0)
{
// the smallest key may have changed
return childInsert;
}
return null; // no change in smallest key
}
/// <summary>
/// Find near-index of comparekey in leaf under this node.
/// </summary>
/// <param name="CompareKey">the key to look for</param>
/// <param name="inLeaf">the leaf where found</param>
/// <param name="LookPastOnly">If true then only look for a greater value, not an exact match.</param>
/// <returns>index of match in leaf</returns>
int FindAtOrNextPositionInLeaf(string CompareKey, out BplusNode inLeaf, bool LookPastOnly, bool caseSensitive)
{
int myposition = this.FindAtOrNextPosition(CompareKey, LookPastOnly, caseSensitive);
if (this.isLeaf)
{
inLeaf = this;
return myposition;
}
long childBufferNumber = this.ChildBufferNumbers[myposition];
if (childBufferNumber==BplusTreeLong.NULLBUFFERNUMBER)
{
throw new BplusTreeException("can't search null subtree");
}
BplusNode child = this.MaterializeNodeAtIndex(myposition);
return child.FindAtOrNextPositionInLeaf(CompareKey, out inLeaf, LookPastOnly, caseSensitive);
}
/// <summary>
/// insert key/position entry in self (as leaf)
/// </summary>
/// <param name="key">Key to associate with the leaf</param>
/// <param name="position">position associated with key in external structure</param>
/// <param name="splitString">if not null then the smallest key in the new split leaf</param>
/// <param name="splitNode">if not null then the node was split and this is the leaf to the right.</param>
/// <returns>smallest key value in keys, or null if no change</returns>
public string InsertLeaf(string key, long position, out string splitString, out BplusNode splitNode)
{
splitString = null;
splitNode = null;
bool dosplit = false;
if (!this.isLeaf)
{
throw new BplusTreeException("bad call to InsertLeaf: this is not a leaf");
}
this.Soil();
int insertposition = this.FindAtOrNextPosition(key, false, true);
if (insertposition>=this.Size)
{
//throw new BplusTreeException("key too big and leaf is full");
dosplit = true;
this.PrepareForSplit();
}
else
{
// if it's already there then change the value at the current location (duplicate entries not supported).
if (this.ChildKeys[insertposition]==null || this.owner.Compare(this.ChildKeys[insertposition], key, true)==0) // this.ChildKeys[insertposition].Equals(key)
{
this.ChildBufferNumbers[insertposition] = position;
this.ChildKeys[insertposition] = key;
if (insertposition==0)
{
return key;
}
else
{
return null;
}
}
}
// check for a null position
int nullindex = insertposition;
while (nullindex<this.ChildKeys.Length && this.ChildKeys[nullindex]!=null)
{
nullindex++;
}
if (nullindex>=this.ChildKeys.Length)
{
if (dosplit)
{
throw new BplusTreeException("can't split twice!!");
}
//throw new BplusTreeException("no space in leaf");
dosplit = true;
this.PrepareForSplit();
}
// bubble in the new info XXXX THIS SHOULD BUBBLE BACKWARDS
string nextkey = this.ChildKeys[insertposition];
long nextposition = this.ChildBufferNumbers[insertposition];
this.ChildKeys[insertposition] = key;
this.ChildBufferNumbers[insertposition] = position;
while (nextkey!=null)
{
key = nextkey;
position = nextposition;
insertposition++;
nextkey = this.ChildKeys[insertposition];
nextposition = this.ChildBufferNumbers[insertposition];
this.ChildKeys[insertposition] = key;
this.ChildBufferNumbers[insertposition] = position;
}
// split if needed
if (dosplit)
{
int splitpoint = this.ChildKeys.Length/2;
int splitlength = this.ChildKeys.Length - splitpoint;
splitNode = new BplusNode(this.owner, this.parent, -1, this.isLeaf);
// copy the split info into the splitNode
Array.Copy(this.ChildBufferNumbers, splitpoint, splitNode.ChildBufferNumbers, 0, splitlength);
Array.Copy(this.ChildKeys, splitpoint, splitNode.ChildKeys, 0, splitlength);
Array.Copy(this.MaterializedChildNodes, splitpoint, splitNode.MaterializedChildNodes, 0, splitlength);
splitString = splitNode.ChildKeys[0];
// archive the new node
splitNode.DumpToFreshBuffer();
// store the node data temporarily
long[] buffernumbers = this.ChildBufferNumbers;
string[] keys = this.ChildKeys;
BplusNode[] nodes = this.MaterializedChildNodes;
// repair current node, copy in the other part of the split
this.ChildBufferNumbers = new long[this.Size+1];
this.ChildKeys = new string[this.Size];
this.MaterializedChildNodes = new BplusNode[this.Size+1];
Array.Copy(buffernumbers, 0, this.ChildBufferNumbers, 0, splitpoint);
Array.Copy(keys, 0, this.ChildKeys, 0, splitpoint);
Array.Copy(nodes, 0, this.MaterializedChildNodes, 0, splitpoint);
for (int i=splitpoint; i<this.ChildKeys.Length; i++)
{
this.ChildKeys[i] = null;
this.ChildBufferNumbers[i] = BplusTreeLong.NULLBUFFERNUMBER;
this.MaterializedChildNodes[i] = null;
}
// store the new node
//splitNode.DumpToFreshBuffer();
this.owner.RecordTerminalNode(splitNode);
splitNode.Soil();
}
//return this.ChildKeys[0];
if (insertposition==0)
{
return key; // smallest key changed.
}
else
{
return null; // no change in smallest key
}
}
void Reparent(BplusNode newParent, int parentIndex)
{
// keys and existing parent structure must be updated elsewhere.
m_parent = newParent;
m_indexInParent = parentIndex;
newParent.m_childBufferNumbers[parentIndex] = MyBufferNumber;
newParent.m_materializedChildNodes[parentIndex] = this;
// parent is no longer terminal
m_owner.ForgetTerminalNode(m_parent);
}
