private void UpdateStackProperties(int sizeDiff)
{
StackFrame frame = StackEnd(0);
int sz = FrameCount;
// Walk the stack from the end
for (int i = 1; i < sz; ++i)
{
int childIndex = frame.ChildIndex;
frame = StackEnd(i);
NodeId nodeId = frame.NodeId;
TreeBranch branch = (TreeBranch)FetchNode(nodeId);
branch.SetChildLeafElementCount(branch.GetChildLeafElementCount(childIndex) + sizeDiff, childIndex);
}
}
public void DeleteLeaf(Key key)
{
// Set up the state
StackFrame frame = StackEnd(0);
NodeId thisRef = frame.NodeId;
TreeBranch branchNode = null;
int deleteNodeSize = -1;
Key leftKey = null;
// Walk back through the rest of the stack
int sz = FrameCount;
for (int i = 1; i < sz; ++i)
{
// Find the child_i for the child
// This is the child_i of the child in the current branch
int childIndex = frame.ChildIndex;
// Move the stack frame,
frame = StackEnd(i);
NodeId childId = thisRef;
thisRef = frame.NodeId;
TreeBranch childBranch = branchNode;
branchNode = (TreeBranch)UnfreezeNode(FetchNode(thisRef));
if (deleteNodeSize == -1)
{
deleteNodeSize =
(int)branchNode.GetChildLeafElementCount(childIndex);
}
// If the child branch is empty,
if (childBranch == null || childBranch.IsEmpty)
{
// Delete the reference to it,
if (childIndex == 0 && branchNode.ChildCount > 1)
{
leftKey = branchNode.GetKey(1);
}
branchNode.RemoveChild(childIndex);
// Delete the child branch,
DeleteNode(childId);
}
// Not empty,
else
{
// Replace with the new child node reference
branchNode.SetChild(childBranch.Id, childIndex);
// Set the element count
long newChildSize =
branchNode.GetChildLeafElementCount(childIndex) -
deleteNodeSize;
branchNode.SetChildLeafElementCount(newChildSize, childIndex);
// Can we set the left key reference?
if (childIndex > 0 && leftKey != null)
{
branchNode.SetKeyToLeft(leftKey, childIndex);
leftKey = null;
}
// Has the size of the child reached the lower threshold?
if (childBranch.ChildCount <= 2)
{
// If it has, we need to redistribute the children,
RedistributeBranchElements(branchNode, childIndex, childBranch);
}
}
}
// Finally, set the root node
// If the branch node is a single element, we set the root as the child,
if (branchNode.ChildCount == 1)
{
// This shrinks the height of the tree,
RootNodeId = branchNode.GetChild(0);
DeleteNode(branchNode.Id);
if (TreeHeight != -1)
{
TreeHeight = TreeHeight - 1;
}
}
else
{
// Otherwise, we set the branch node.
RootNodeId = branchNode.Id;
}
// Reset the object
Reset();
}
public void SetupForPosition(Key key, long posit)
{
// If the current leaf is set
if (currentLeaf != null)
{
StackFrame frame = StackEnd(0);
long leafStart = frame.Offset;
long leafEnd = leafStart + currentLeaf.Length;
// If the position is at the leaf end, or if the keys aren't equal, we
// need to reset the stack. This ensures that we correctly place the
// pointer.
if (!key.Equals(Key.Tail) &&
(posit == leafEnd || !key.Equals(currentLeafKey)))
{
StackClear();
currentLeaf = null;
currentLeafKey = null;
}
else
{
// Check whether the position is within the bounds of the current leaf
// If 'posit' is within this leaf
if (posit >= leafStart && posit < leafEnd)
{
// If the position is within the current leaf, set up the internal
// vars as necessary.
leafOffset = (int)(posit - leafStart);
return;
}
// If it's not, we reset the stack and start fresh,
StackClear();
currentLeaf = null;
currentLeafKey = null;
}
}
// ISSUE: It appears looking at the code above, the stack will always be
// empty and current_leaf will always be null if we get here.
// If the stack is empty, push the root node,
if (StackEmpty)
{
// Push the root node onto the top of the stack.
StackPush(-1, 0, RootNodeId);
// Set up the current_leaf_key to the default value
currentLeafKey = Key.Head;
}
// Otherwise, we need to setup by querying the BTree.
while (true)
{
if (StackEmpty)
{
throw new ApplicationException("Position out of bounds. p = " + posit);
}
// Pop the last stack frame,
StackFrame frame = StackPop();
NodeId nodePointer = frame.NodeId;
long leftSideOffset = frame.Offset;
int nodeChildIndex = frame.ChildIndex;
// Relative offset within this node
long relativeOffset = posit - leftSideOffset;
// If the node is not on the heap,
if (!IsHeapNode(nodePointer))
{
// The node is not on the heap. We optimize here.
// If we know the node is going to be a leaf node, we set up a
// temporary leaf node object with as much information as we know.
// Check if we know this is a leaf
int treeHeight = TreeHeight;
if (treeHeight != -1 &&
(stackSize / StackFrameSize) + 1 == treeHeight)
{
// Fetch the parent node,
frame = StackEnd(0);
NodeId twigNodePointer = frame.NodeId;
TreeBranch twig = (TreeBranch)FetchNode(twigNodePointer);
long leafSize =
twig.GetChildLeafElementCount(nodeChildIndex);
// This object holds off fetching the contents of the leaf node
// unless it's absolutely required.
TreeLeaf leaf =
new PlaceholderLeaf(ts, nodePointer, (int)leafSize);
currentLeaf = leaf;
StackPush(nodeChildIndex, leftSideOffset, nodePointer);
// Set up the leaf offset and return
leafOffset = (int)relativeOffset;
return;
}
}
// Fetch the node
ITreeNode node = FetchNode(nodePointer);
if (node is TreeLeaf)
{
// Node is a leaf node
TreeLeaf leaf = (TreeLeaf)node;
currentLeaf = leaf;
StackPush(nodeChildIndex, leftSideOffset, nodePointer);
// Set up the leaf offset and return
leafOffset = (int)relativeOffset;
// Update the tree_height value,
TreeHeight = stackSize / StackFrameSize;
return;
}
// Node is a branch node
TreeBranch branch = (TreeBranch)node;
int childIndex = branch.IndexOfChild(key, relativeOffset);
if (childIndex != -1)
{
// Push the current details,
StackPush(nodeChildIndex, leftSideOffset, nodePointer);
// Found child so push the details
StackPush(childIndex,
branch.GetChildOffset(childIndex) + leftSideOffset,
branch.GetChild(childIndex));
// Set up the left key
if (childIndex > 0)
{
currentLeafKey = branch.GetKey(childIndex);
}
}
} // while (true)
}
public void InsertLeaf(Key newLeafKey, TreeLeaf newLeaf, bool before)
{
int leafSize = newLeaf.Length;
if (leafSize <= 0)
{
throw new ArgumentException("size <= 0");
}
// The current absolute position and key
Key newKey = newLeafKey;
// The frame at the end of the stack,
StackFrame frame = StackEnd(0);
object[] info;
object[] rInfo = new object[5];
Key leftKey;
long curAbsolutePos;
// If we are inserting the new leaf after,
if (!before)
{
info = new object[] {
currentLeaf.Id,
(long)currentLeaf.Length,
newLeafKey,
newLeaf.Id,
(long)newLeaf.Length
};
leftKey = null;
curAbsolutePos = frame.Offset + currentLeaf.Length;
}
// Otherwise we are inserting the new leaf before,
else
{
// If before and current_leaf key is different than new_leaf key, we
// generate an error
if (!currentLeafKey.Equals(newLeafKey))
{
throw new InvalidOperationException("Can't insert different new key before.");
}
info = new Object[] {
newLeaf.Id,
(long)newLeaf.Length,
currentLeafKey,
currentLeaf.Id,
(long)currentLeaf.Length
};
leftKey = newLeafKey;
curAbsolutePos = frame.Offset - 1;
}
bool insertTwoNodes = true;
int sz = FrameCount;
// Walk the stack from the end
for (int i = 1; i < sz; ++i)
{
// child_i is the previous frame's child_i
int childIndex = frame.ChildIndex;
frame = StackEnd(i);
// The child ref of this stack element
NodeId childId = frame.NodeId;
// Fetch it
TreeBranch branch = (TreeBranch)UnfreezeNode(FetchNode(childId));
// Do we have two nodes to insert into the branch?
if (insertTwoNodes)
{
TreeBranch insertBranch;
int insertIndex = childIndex;
// If the branch is full,
if (branch.IsFull)
{
// Create a new node,
TreeBranch leftBranch = branch;
TreeBranch rightBranch = CreateBranch();
// Split the branch,
Key midpointKey = leftBranch.MidPointKey;
// And move half of this branch into the new branch
leftBranch.MoveLastHalfInto(rightBranch);
// We split so we need to return a split flag,
rInfo[0] = leftBranch.Id;
rInfo[1] = leftBranch.LeafElementCount;
rInfo[2] = midpointKey;
rInfo[3] = rightBranch.Id;
rInfo[4] = rightBranch.LeafElementCount;
// Adjust insert_n and insert_branch
if (insertIndex >= leftBranch.ChildCount)
{
insertIndex -= leftBranch.ChildCount;
insertBranch = rightBranch;
rInfo[4] = (long)rInfo[4] + newLeaf.Length;
// If insert_n == 0, we change the midpoint value to the left
// key value,
if (insertIndex == 0 && leftKey != null)
{
rInfo[2] = leftKey;
leftKey = null;
}
}
else
{
insertBranch = leftBranch;
rInfo[1] = (long)rInfo[1] + newLeaf.Length;
}
}
// If it's not full,
else
{
insertBranch = branch;
rInfo[0] = insertBranch.Id;
insertTwoNodes = false;
}
// Insert the two children nodes
insertBranch.Insert((NodeId)info[0], (long)info[1],
(Key)info[2],
(NodeId)info[3], (long)info[4],
insertIndex);
// Copy r_nfo to nfo
for (int p = 0; p < rInfo.Length; ++p)
{
info[p] = rInfo[p];
}
// Adjust the left key reference if necessary
if (leftKey != null && insertIndex > 0)
{
insertBranch.SetKeyToLeft(leftKey, insertIndex);
leftKey = null;
}
}
else
{
branch.SetChild((NodeId)info[0], childIndex);
info[0] = branch.Id;
branch.SetChildLeafElementCount(
branch.GetChildLeafElementCount(childIndex) + leafSize, childIndex);
// Adjust the left key reference if necessary
if (leftKey != null && childIndex > 0)
{
branch.SetKeyToLeft(leftKey, childIndex);
leftKey = null;
}
}
} // For all elements in the stack,
// At the end, if we still have a split then we make a new root and
// adjust the stack accordingly
if (insertTwoNodes)
{
TreeBranch newRoot = CreateBranch();
newRoot.Set((NodeId)info[0], (long)info[1],
(Key)info[2],
(NodeId)info[3], (long)info[4]);
RootNodeId = newRoot.Id;
if (TreeHeight != -1)
{
TreeHeight = TreeHeight + 1;
}
}
else
{
RootNodeId = (NodeId)info[0];
}
// Now reset the position,
Reset();
SetupForPosition(newKey, curAbsolutePos);
}
private TreeGraph CreateRootGraph(Key leftKey, long reference)
{
// The node being returned
TreeGraph graph;
// Open the area
IArea area = store.GetArea(reference);
// What type of node is this?
short nodeType = area.ReadInt2();
// The version
short ver = area.ReadInt2();
if (nodeType == LeafType) {
// Read the reference count,
long refCount = area.ReadInt4();
// The number of bytes in the leaf
int leafSize = area.ReadInt4();
// Set up the leaf node object
graph = new TreeGraph("leaf", reference);
graph.SetProperty("ver", ver);
graph.SetProperty("key", leftKey.ToString());
graph.SetProperty("reference_count", refCount);
graph.SetProperty("leaf_size", leafSize);
} else if (nodeType == BranchType) {
// The data size area containing the children information
int childDataSize = area.ReadInt4();
long[] data = new long[childDataSize];
for (int i = 0; i < childDataSize; ++i) {
data[i] = area.ReadInt8();
}
// Create the TreeBranch object to query it
TreeBranch branch = new TreeBranch(reference, data, childDataSize);
// Set up the branch node object
graph = new TreeGraph("branch", reference);
graph.SetProperty("ver", ver);
graph.SetProperty("key", leftKey.ToString());
graph.SetProperty("branch_size", branch.ChildCount);
// Recursively add each child into the tree
for (int i = 0; i < branch.ChildCount; ++i) {
long child_ref = branch.GetChild(i);
// If the ref is a special node, skip it
if ((child_ref & 0x01000000000000000L) != 0) {
// Should we record special nodes?
} else {
Key newLeftKey = (i > 0) ? branch.GetKey(i) : leftKey;
TreeGraph bn = new TreeGraph("child_meta", reference);
bn.SetProperty("extent", branch.GetChildLeafElementCount(i));
graph.AddChild(bn);
graph.AddChild(CreateRootGraph(newLeftKey, child_ref));
}
}
} else {
throw new IOException("Unknown node type: " + nodeType);
}
return graph;
}
private TreeReportNode CreateDiagnosticRootGraph(Key leftKey, NodeId id)
{
// The node being returned
TreeReportNode node;
// Open the area
IArea area = nodeStore.GetArea(ToInt64StoreAddress(id));
// What type of node is this?
short nodeType = area.ReadInt2();
// The version
short ver = area.ReadInt2();
if (nodeType == StoreLeafType)
{
// Read the reference count,
long refCount = area.ReadInt4();
// The number of bytes in the leaf
int leafSize = area.ReadInt4();
// Set up the leaf node object
node = new TreeReportNode("leaf", id);
node.SetProperty("VER", ver);
node.SetProperty("key", leftKey.ToString());
node.SetProperty("reference_count", refCount);
node.SetProperty("leaf_size", leafSize);
}
else if (nodeType == StoreBranchType)
{
// The data size area containing the children information
int childDataSize = area.ReadInt4();
long[] dataArr = new long[childDataSize];
for (int i = 0; i < childDataSize; ++i)
{
dataArr[i] = area.ReadInt8();
}
// Create the TreeBranch object to query it
TreeBranch branch = new TreeBranch(id, dataArr, childDataSize);
// Set up the branch node object
node = new TreeReportNode("branch", id);
node.SetProperty("VER", ver);
node.SetProperty("key", leftKey.ToString());
node.SetProperty("branch_size", branch.ChildCount);
// Recursively add each child into the tree
for (int i = 0; i < branch.ChildCount; ++i)
{
NodeId childId = branch.GetChild(i);
// If the id is a special node, skip it
if (childId.IsSpecial)
{
// Should we record special nodes?
}
else
{
Key newLeftKey = (i > 0) ? branch.GetKey(i) : leftKey;
TreeReportNode bn = new TreeReportNode("child_meta", id);
bn.SetProperty("extent", branch.GetChildLeafElementCount(i));
node.ChildNodes.Add(bn);
node.ChildNodes.Add(CreateDiagnosticRootGraph(newLeftKey, childId));
}
}
}
else
{
throw new IOException("Unknown node type: " + nodeType);
}
return(node);
}
private TreeReportNode CreateDiagnosticRootGraph(Key leftKey, NodeId id)
{
// The node being returned
TreeReportNode node;
// Open the area
IArea area = nodeStore.GetArea(ToInt64StoreAddress(id));
// What type of node is this?
short nodeType = area.ReadInt2();
// The version
short ver = area.ReadInt2();
if (nodeType == StoreLeafType) {
// Read the reference count,
long refCount = area.ReadInt4();
// The number of bytes in the leaf
int leafSize = area.ReadInt4();
// Set up the leaf node object
node = new TreeReportNode("leaf", id);
node.SetProperty("VER", ver);
node.SetProperty("key", leftKey.ToString());
node.SetProperty("reference_count", refCount);
node.SetProperty("leaf_size", leafSize);
} else if (nodeType == StoreBranchType) {
// The data size area containing the children information
int childDataSize = area.ReadInt4();
long[] dataArr = new long[childDataSize];
for (int i = 0; i < childDataSize; ++i) {
dataArr[i] = area.ReadInt8();
}
// Create the TreeBranch object to query it
TreeBranch branch = new TreeBranch(id, dataArr, childDataSize);
// Set up the branch node object
node = new TreeReportNode("branch", id);
node.SetProperty("VER", ver);
node.SetProperty("key", leftKey.ToString());
node.SetProperty("branch_size", branch.ChildCount);
// Recursively add each child into the tree
for (int i = 0; i < branch.ChildCount; ++i) {
NodeId childId = branch.GetChild(i);
// If the id is a special node, skip it
if (childId.IsSpecial) {
// Should we record special nodes?
} else {
Key newLeftKey = (i > 0) ? branch.GetKey(i) : leftKey;
TreeReportNode bn = new TreeReportNode("child_meta", id);
bn.SetProperty("extent", branch.GetChildLeafElementCount(i));
node.ChildNodes.Add(bn);
node.ChildNodes.Add(CreateDiagnosticRootGraph(newLeftKey, childId));
}
}
} else {
throw new IOException("Unknown node type: " + nodeType);
}
return node;
}
