private static unsafe void DisposeTree(BTreeNode* root)
{
int i;
if (root->IsLeaf)
{
for (i = 0; i < root->NumKeys; i++)
{
Memory.Free(root->Pointers[i]);
}
}
else
{
for (i = 0; i < root->NumKeys + 1; i++)
{
DisposeTree((BTreeNode*)root->Pointers[i]);
}
}
Memory.Free(root->Keys);
Memory.Free(root->Pointers);
Memory.Free(root);
}
private unsafe BTreeNode* ReadKeys(BinaryReader reader, BTreeNode* parent)
{
BTreeNode* node;
var isLeaf = reader.ReadBoolean();
if (isLeaf)
{
node = MakeLeaf();
}
else
{
node = MakeNode();
}
node->Parent = parent;
var numKeys = reader.ReadInt32();
node->NumKeys = numKeys;
for (var i = 0; i < numKeys; i++)
{
node->Keys[i] = reader.ReadUInt64();
if (!node->IsLeaf)
{
var child = ReadKeys(reader, node);
node->Pointers[i] = child;
}
else
{
node->Pointers[i] = ReadValues(reader);
}
}
if (!node->IsLeaf)
{
var child = ReadKeys(reader, node);
node->Pointers[node->NumKeys] = child;
}
else
{
}
return node;
}
private unsafe void WriteKeys(BinaryWriter writer, BTreeNode* node)
{
writer.Write(node->IsLeaf);
writer.Write(node->NumKeys);
for (var i = 0; i < node->NumKeys; i++)
{
writer.Write(node->Keys[i]);
if (!node->IsLeaf)
{
WriteKeys(writer, (BTreeNode*)node->Pointers[i]);
}
else
{
WriteValues(writer, (BTreeRecord*)node->Pointers[i]);
}
}
if (!node->IsLeaf)
{
WriteKeys(writer, (BTreeNode*)node->Pointers[node->NumKeys]);
}
}
private unsafe BTreeNode* InsertIntoNodeAfterSplitting(BTreeNode* root, BTreeNode* oldNode, int leftIndex, ulong key, BTreeNode* right)
{
int i, j, split;
ulong kPrime;
BTreeNode* newNode, child;
ulong* tempKeys;
BTreeNode** tempPointers;
tempKeys = (ulong*)Memory.Alloc<ulong>(Order);
tempPointers = (BTreeNode**)Memory.Alloc(typeof(BTreeNode*), Order + 1);
for (i = 0, j = 0; i < oldNode->NumKeys; i++, j++)
{
if (j == leftIndex) j++;
tempKeys[j] = oldNode->Keys[i];
}
for (i = 0, j = 0; i < oldNode->NumKeys + 1; i++, j++)
{
if (j == leftIndex + 1) j++;
tempPointers[j] = (BTreeNode*)oldNode->Pointers[i];
}
tempKeys[leftIndex] = key;
tempPointers[leftIndex + 1] = right;
split = Cut(Order);
newNode = MakeNode();
oldNode->NumKeys = 0;
for (i = 0; i < split - 1; i++)
{
oldNode->Keys[i] = tempKeys[i];
oldNode->Pointers[i] = tempPointers[i];
oldNode->NumKeys++;
}
oldNode->Pointers[i] = tempPointers[i];
kPrime = tempKeys[split - 1];
for (++i, j = 0; i < Order; i++, j++)
{
newNode->Keys[j] = tempKeys[i];
newNode->Pointers[j] = tempPointers[i];
newNode->NumKeys++;
}
newNode->Pointers[j] = tempPointers[i];
Memory.Free(tempKeys);
Memory.Free(tempPointers);
newNode->Parent = oldNode->Parent;
for (i = 0; i <= newNode->NumKeys; i++)
{
child = (BTreeNode*)newNode->Pointers[i];
child->Parent = newNode;
}
return InsertIntoParent(root, oldNode, kPrime, newNode);
}
private unsafe BTreeNode* InsertIntoParent(BTreeNode* root, BTreeNode* left, ulong key, BTreeNode* right)
{
int leftIndex;
BTreeNode* parent;
parent = left->Parent;
if (parent == null)
{
return InsertIntoNewRoot(left, key, right);
}
leftIndex = GetLeftIndex(parent, left);
if (parent->NumKeys < Order - 1)
{
InsertIntoNode(parent, leftIndex, key, right);
return root;
}
return InsertIntoNodeAfterSplitting(root, parent, leftIndex, key, right);
}
private unsafe BTreeNode* InsertIntoNewRoot(BTreeNode* left, ulong key, BTreeNode* right)
{
BTreeNode* root = MakeNode();
root->Keys[0] = key;
root->Pointers[0] = left;
root->Pointers[1] = right;
root->NumKeys++;
root->Parent = null;
left->Parent = root;
right->Parent = root;
return root;
}
private unsafe void InsertIntoNode(BTreeNode* node, int leftIndex, ulong key, BTreeNode* right)
{
int i;
for (i = node->NumKeys; i > leftIndex; i--)
{
node->Keys[i] = node->Keys[i - 1];
node->Pointers[i + 1] = node->Pointers[i];
}
node->Keys[leftIndex] = key;
node->Pointers[leftIndex + 1] = right;
node->NumKeys++;
}
private unsafe BTreeNode* InsertIntoLeafAfterSplitting(BTreeNode* root, BTreeNode* leaf, ulong key, BTreeRecord* pointer)
{
ulong newKey;
BTreeNode* newLeaf;
ulong* tempKeys;
void** tempPointers;
int insertionIndex, split, i, j;
newLeaf = MakeLeaf();
tempKeys = (ulong*)Memory.Alloc<ulong>(Order);
tempPointers = Memory.AllocVoid(Order + 1);
insertionIndex = 0;
while (insertionIndex < Order - 1 && leaf->Keys[insertionIndex] < key)
{
insertionIndex++;
}
for (i = 0, j = 0; i < leaf->NumKeys; i++, j++)
{
if (j == insertionIndex) j++;
tempKeys[j] = leaf->Keys[i];
tempPointers[j] = leaf->Pointers[i];
}
tempKeys[insertionIndex] = key;
tempPointers[insertionIndex] = pointer;
leaf->NumKeys = 0;
split = Cut(Order - 1);
for (i = 0; i < split; i++)
{
leaf->Keys[i] = tempKeys[i];
leaf->Pointers[i] = tempPointers[i];
leaf->NumKeys++;
}
for (i = split, j = 0; i < Order; i++, j++)
{
newLeaf->Keys[j] = tempKeys[i];
newLeaf->Pointers[j] = tempPointers[i];
newLeaf->NumKeys++;
}
Memory.Free(tempKeys);
Memory.Free(tempPointers);
newLeaf->Pointers[Order - 1] = leaf->Pointers[Order - 1];
leaf->Pointers[Order - 1] = newLeaf;
for (i = leaf->NumKeys; i < Order - 1; i++)
{
leaf->Pointers[i] = null;
}
for (i = newLeaf->NumKeys; i < Order - 1; i++)
{
newLeaf->Pointers[i] = null;
}
newLeaf->Parent = leaf->Parent;
newKey = newLeaf->Keys[0];
return InsertIntoParent(root, leaf, newKey, newLeaf);
}
private unsafe int GetLeftIndex(BTreeNode* parent, BTreeNode* left)
{
int leftIndex = 0;
while (leftIndex <= parent->NumKeys && parent->Pointers[leftIndex] != left)
{
leftIndex++;
}
return leftIndex;
}
private static unsafe BTreeNode* InsertIntoLeaf(BTreeNode* leaf, ulong key, BTreeRecord* pointer)
{
var insertionPoint = 0;
while (insertionPoint < leaf->NumKeys && leaf->Keys[insertionPoint] < key)
{
insertionPoint++;
}
for (var i = leaf->NumKeys; i > insertionPoint; i--)
{
leaf->Keys[i] = leaf->Keys[i - 1];
leaf->Pointers[i] = leaf->Pointers[i - 1];
}
leaf->Keys[insertionPoint] = key;
leaf->Pointers[insertionPoint] = pointer;
leaf->NumKeys++;
return leaf;
}
private static unsafe BTreeNode* FindLeaf(BTreeNode* root, ulong key)
{
var node = root;
if (node == null) return null;
while (!node->IsLeaf)
{
var i = 0;
while (i < node->NumKeys)
{
if (key >= node->Keys[i]) i++;
else break;
}
node = (BTreeNode*)node->Pointers[i];
}
return node;
}
private static unsafe ulong* Find(BTreeNode* root, ulong key)
{
int i;
var node = FindLeaf(root, key);
if (node == null) return null;
for (i = 0; i < node->NumKeys; i++)
{
if (node->Keys[i] == key)
{
break;
}
}
return i == node->NumKeys ? null : (*((BTreeRecord*)node->Pointers[i])).Value;
}