public void DeleteNodeEntry(NodeID nodeID)
{
NodeBTreeLeafPage leaf = (NodeBTreeLeafPage)FindLeafBTreePage(nodeID.Value);
// Remove the entry
int index = leaf.RemoveEntry(nodeID.Value);
if (index == 0)
{
// scanpst.exe report an error if page key does not match the first entry,
// so we want to update the parent
if (leaf.ParentPage != null)
{
if (leaf.NodeEntryList.Count > 0)
{
UpdateIndexEntry(leaf.ParentPage, leaf.BlockID, leaf.PageKey);
}
else
{
DeleteIndexEntry(leaf.ParentPage, leaf.BlockID);
DeletePage(leaf);
return;
}
}
}
// now we have to store the new leaf page, and cascade the changes up to the root page
UpdatePageAndReferences(leaf);
}
public static BTreePage ReadFromStream(Stream stream, BlockRef blockRef)
{
long offset = (long)blockRef.ib;
stream.Seek(offset, SeekOrigin.Begin);
byte[] buffer = new byte[Length];
stream.Read(buffer, 0, Length);
PageTypeName ptype = (PageTypeName)buffer[PageTrailer.OffsetFromPageStart + 0];
BTreePage page;
byte cLevel = buffer[491];
if (cLevel > 0)
{
// If cLevel is greater than 0, then each entry in the array is of type BTENTRY.
page = new BTreeIndexPage(buffer);
}
else
{
// If cLevel is 0, then each entry is either of type BBTENTRY or NBTENTRY, depending on the ptype of the page.
if (ptype == PageTypeName.ptypeBBT)
{
page = new BlockBTreeLeafPage(buffer);
}
else if (ptype == PageTypeName.ptypeNBT)
{
page = new NodeBTreeLeafPage(buffer);
}
else
{
throw new ArgumentException("BTreePage has incorrect ptype");
}
}
page.Offset = (ulong)blockRef.ib;
if (blockRef.bid.Value != page.BlockID.Value)
{
throw new InvalidBlockIDException();
}
uint crc = PSTCRCCalculation.ComputeCRC(buffer, PageTrailer.OffsetFromPageStart);
if (page.pageTrailer.dwCRC != crc)
{
throw new InvalidChecksumException();
}
uint signature = BlockTrailer.ComputeSignature(blockRef.ib, blockRef.bid.Value);
if (page.pageTrailer.wSig != signature)
{
throw new InvalidChecksumException();
}
return(page);
}
public NodeBTreeEntry FindNodeEntryByNodeID(uint nodeID)
{
NodeBTreeLeafPage page = (NodeBTreeLeafPage)FindLeafBTreePage(nodeID);
if (page != null)
{
// page.cLevel is now 0
List <NodeBTreeEntry> nodeEntryList = page.NodeEntryList;
foreach (NodeBTreeEntry entry in nodeEntryList)
{
if (entry.nid.Value == nodeID)
{
return(entry);
}
}
}
return(null);
}
public NodeBTreeLeafPage Split()
{
int newNodeStartIndex = NodeEntryList.Count / 2;
NodeBTreeLeafPage newPage = new NodeBTreeLeafPage();
// BlockID will be given when the page will be added
newPage.cEntMax = cEntMax;
newPage.cbEnt = cbEnt;
newPage.cLevel = cLevel;
newPage.pageTrailer.ptype = pageTrailer.ptype;
for (int index = newNodeStartIndex; index < NodeEntryList.Count; index++)
{
newPage.NodeEntryList.Add(NodeEntryList[index]);
}
NodeEntryList.RemoveRange(newNodeStartIndex, NodeEntryList.Count - newNodeStartIndex);
return(newPage);
}
public void InsertNodeEntry(NodeBTreeEntry entryToInsert)
{
ulong key = entryToInsert.nid.Value;
NodeBTreeLeafPage page = (NodeBTreeLeafPage)FindLeafBTreePage(key);
if (page.NodeEntryList.Count < NodeBTreeLeafPage.MaximumNumberOfEntries)
{
int insertIndex = page.InsertSorted(entryToInsert);
UpdatePageAndReferences(page);
if (insertIndex == 0 && page.ParentPage != null)
{
// page key has been modified, we must update the parent
UpdateIndexEntry(page.ParentPage, page.BlockID, page.PageKey);
}
}
else
{
// We have to split the tree node
NodeBTreeLeafPage newPage = page.Split();
if (newPage.PageKey < key)
{
newPage.InsertSorted(entryToInsert);
}
else
{
int insertIndex = page.InsertSorted(entryToInsert);
if (insertIndex == 0 && page.ParentPage != null)
{
// page key has been modified, we must update the parent
UpdateIndexEntry(page.ParentPage, page.BlockID, page.PageKey);
}
}
UpdatePageAndReferences(page);
AddPage(newPage);
if (page.ParentPage == null)
{
// this is a root page and it's full, we have to create a new root
CreateNewRoot();
}
InsertIndexEntry(page.ParentPage, newPage.NodeEntryList[0].nid.Value, newPage.BlockID);
}
}
public void UpdateNodeEntry(NodeID nodeID, DataTree dataTree, SubnodeBTree subnodeBTree)
{
NodeBTreeLeafPage leaf = (NodeBTreeLeafPage)FindLeafBTreePage(nodeID.Value);
int index = leaf.GetIndexOfEntry(nodeID.Value);
if (index >= 0)
{
leaf.NodeEntryList[index].bidData = new BlockID(0);
if (dataTree != null && dataTree.RootBlock != null)
{
leaf.NodeEntryList[index].bidData = dataTree.RootBlock.BlockID;
}
leaf.NodeEntryList[index].bidSub = new BlockID(0);
if (subnodeBTree != null && subnodeBTree.RootBlock != null)
{
leaf.NodeEntryList[index].bidSub = subnodeBTree.RootBlock.BlockID;
}
// now we have to store the new leaf page, and cascade the changes up to the root page
UpdatePageAndReferences(leaf);
}
}
