protected void DeleteIndexEntry(BTreeIndexPage indexPage, BlockID blockIDOfChild)
{
for (int index = 0; index < indexPage.IndexEntryList.Count; index++)
{
BTreeIndexEntry entry = indexPage.IndexEntryList[index];
if (entry.BREF.bid.Value == blockIDOfChild.Value)
{
indexPage.IndexEntryList.RemoveAt(index);
UpdatePageAndReferences(indexPage); // parents will now refer to the new blockID
if (index == 0 && indexPage.ParentPage != null)
{
if (indexPage.IndexEntryList.Count > 0)
{
// page key has been modified, we must update the parent as well
UpdateIndexEntry(indexPage.ParentPage, indexPage.BlockID, indexPage.PageKey);
}
else
{
DeleteIndexEntry(indexPage.ParentPage, indexPage.BlockID);
DeletePage(indexPage);
}
}
}
}
}
/// <returns>Insert index</returns>
public int InsertSorted(BTreeIndexEntry entryToInsert)
{
int insertIndex = GetSortedInsertIndex(entryToInsert);
IndexEntryList.Insert(insertIndex, entryToInsert);
return(insertIndex);
}
private void InsertSorted(ulong btkey, BlockID blockID)
{
BTreeIndexEntry entry = new BTreeIndexEntry();
entry.BREF.bid = blockID;
InsertSorted(entry);
}
protected void InsertIndexEntry(BTreeIndexPage indexPage, ulong btkey, BlockID blockID)
{
BTreeIndexEntry indexEntry = new BTreeIndexEntry();
indexEntry.btkey = btkey;
indexEntry.BREF.bid = blockID;
InsertIndexEntry(indexPage, indexEntry);
}
public override void PopulateEntries(byte[] buffer, byte numberOfEntries)
{
for (int index = 0; index < numberOfEntries; index++)
{
int offset = index * cbEnt;
BTreeIndexEntry entry = new BTreeIndexEntry(buffer, offset);
IndexEntryList.Add(entry);
}
}
public int GetSortedInsertIndex(BTreeIndexEntry entryToInsert)
{
ulong key = entryToInsert.btkey;
int insertIndex = 0;
while (insertIndex < IndexEntryList.Count && key > IndexEntryList[insertIndex].btkey)
{
insertIndex++;
}
return(insertIndex);
}
public int GetIndexOfEntryWithMatchingRange(ulong key)
{
int lastToMatchIndex = 0;
for (int index = 1; index < IndexEntryList.Count; index++)
{
BTreeIndexEntry entry = IndexEntryList[index];
// All the entries in the child BTPAGE .. have key values greater than or equal to this key value.
if (key >= entry.btkey)
{
lastToMatchIndex = index;
}
}
return(lastToMatchIndex);
}
public void CreateNewRoot()
{
BTreeIndexPage newRoot = BTreeIndexPage.GetEmptyIndexPage(m_bTreeRootPage.pageTrailer.ptype, m_bTreeRootPage.cLevel + 1);
BTreeIndexEntry rootIndexEntry = new BTreeIndexEntry();
// We make sure the old root page has been updated (to prevent the BlockID from changing during update)
UpdatePage(m_bTreeRootPage);
rootIndexEntry.btkey = m_bTreeRootPage.PageKey;
rootIndexEntry.BREF.bid = m_bTreeRootPage.BlockID;
rootIndexEntry.BREF.ib = 0; // this will tell BufferedBTreePageStore that the block hasn't been written yet
newRoot.IndexEntryList.Add(rootIndexEntry);
AddPage(newRoot);
m_bTreeRootPage.ParentPage = newRoot;
m_bTreeRootPage = newRoot;
}
private void CascadeUpReferenceUpdate(BTreeIndexPage indexPage, ulong oldBlockID, ulong newBlockID)
{
int index = indexPage.GetIndexOfBlockID(oldBlockID);
if (index >= 0)
{
BTreeIndexEntry entry = indexPage.IndexEntryList[index];
entry.BREF.bid = new BlockID(newBlockID);
entry.BREF.ib = 0; // this will tell BufferedBTreePageStore that the block hasn't been written yet
ulong currentBlockID = indexPage.BlockID.Value;
UpdatePage(indexPage);
if (currentBlockID != indexPage.BlockID.Value &&
indexPage.ParentPage != null)
{
CascadeUpReferenceUpdate(indexPage.ParentPage, currentBlockID, indexPage.BlockID.Value);
}
}
}
protected void InsertIndexEntry(BTreeIndexPage indexPage, BTreeIndexEntry entryToInsert)
{
if (indexPage.IndexEntryList.Count < BTreeIndexPage.MaximumNumberOfEntries)
{
int insertIndex = indexPage.InsertSorted(entryToInsert);
UpdatePageAndReferences(indexPage);
if (insertIndex == 0 && indexPage.ParentPage != null)
{
// page key has been modified, we must update the parent
UpdateIndexEntry(indexPage.ParentPage, indexPage.BlockID, indexPage.PageKey);
}
}
else
{
// The tree node is full, we have to split it
BTreeIndexPage newPage = indexPage.Split();
if (newPage.PageKey < entryToInsert.btkey)
{
newPage.InsertSorted(entryToInsert);
}
else
{
int insertIndex = indexPage.InsertSorted(entryToInsert);
if (insertIndex == 0 && indexPage.ParentPage != null)
{
// page key has been modified, we must update the parent
UpdateIndexEntry(indexPage.ParentPage, indexPage.BlockID, indexPage.PageKey);
}
}
UpdatePageAndReferences(indexPage);
AddPage(newPage);
if (indexPage.ParentPage == null)
{
// this is a root page and it's full, we have to create a new root
CreateNewRoot();
}
// We made sure we have a parent to add our new page to
InsertIndexEntry(indexPage.ParentPage, newPage.PageKey, newPage.BlockID);
}
}
/// <summary>
/// Find the leaf BTreePage where the entry with the given key should be located
/// We use this method for search and insertion
/// Note: the returned BTreePage will have its ParentPage set (can be traversed up to the bTreeRootPage)
/// </summary>
protected BTreePage FindLeafBTreePage(ulong key)
{
BTreePage currentPage = m_bTreeRootPage;
int cLevel = m_bTreeRootPage.cLevel;
while (cLevel > 0)
{
int matchingIndex = ((BTreeIndexPage)currentPage).GetIndexOfEntryWithMatchingRange(key);
BTreeIndexEntry matchingEntry = ((BTreeIndexPage)currentPage).IndexEntryList[matchingIndex];
BTreePage childPage = GetPage(matchingEntry.BREF);
childPage.ParentPage = (BTreeIndexPage)currentPage;
currentPage = childPage;
cLevel--;
if (cLevel != currentPage.cLevel)
{
throw new Exception("Invalid Page cLevel");
}
}
return(currentPage);
}
