public override void DeleteKey(IFixedLengthKey key, int offset)
{
RBNodeBase rbNode;
BTreeNode foundNode = SearchBTreeNode(key, offset, out rbNode);
if (foundNode != null)
{
BTreePage page = PreparePage(foundNode);
_count -= foundNode.Count;
page.DeleteKey(key, offset);
int pageCount = foundNode.Count;
_count += pageCount;
long pageOffset;
if (page.Empty())
{
pageOffset = page.BTreeNode.PageOffset;
freePages.Push(pageOffset);
_rbTree.RB_Delete(page.BTreeNode);
_cache.Remove(pageOffset);
}
else if (pageCount < (_maxCount >> 2) && (rbNode = _rbTree.GetNext(rbNode)) != null)
{
BTreeNode rightNode = (BTreeNode)rbNode.Key;
if (pageCount + rightNode.Count < (_maxCount >> 1))
{
BTreePage rightPage = PreparePage(rightNode);
pageOffset = rightPage.BTreeNode.PageOffset;
page.Merge(rightPage);
freePages.Push(pageOffset);
_rbTree.RB_Delete(rightPage.BTreeNode);
_cache.Remove(pageOffset);
}
}
}
}
public BTreePage Split(IFixedLengthKey key, int offset, long pageOffset, float splitFactor)
{
ProcessDeferredUpdates();
if (splitFactor >= 1 || splitFactor < 0.1)
{
throw new Exception("BTreePage.Split: splitFactor = " + splitFactor.ToString() + " is not applicable");
}
int mIndex = (int)(_maxCount * splitFactor);
int off;
IFixedLengthKey minKey = MemoryRead(mIndex, out off).FactoryMethod();
BTreePage splittedPage = new BTreePage(
new BTreeNode(minKey, off, pageOffset, _maxCount - mIndex), _maxCount, _stream, _factoryKey);
CopyBytes(_bytes, mIndex, splittedPage._bytes, 0, _maxCount - mIndex);
_treeNode.SetNewCount(mIndex);
_rightBound = mIndex;
_modified = splittedPage._modified = true;
if (key.CompareTo(minKey) < 0)
{
InsertKey(key, offset);
}
else
{
splittedPage.InsertKey(key, offset);
}
return(splittedPage);
}
public override void Close()
{
_cache.RemoveAll();
_cache = null;
_freeNode = null;
_count = 0;
_reader.Close();
_writer.Close();
_stream.Close();
}
private BTreePage PreparePage(BTreeNode foundNode)
{
BTreePage page = (BTreePage)_cache.TryKey(foundNode.PageOffset);
if (page == null)
{
page = NewPage(foundNode);
page.Read();
_cache.CacheObject(foundNode.PageOffset, page);
}
return(page);
}
public override void GetAllKeys(ArrayList keys_offsets)
{
RBNodeBase rbNode = _rbTree.GetMinimumNode();
while (rbNode != null)
{
BTreePage page = PreparePage((BTreeNode)rbNode.Key);
if (page.GetAllKeys(keys_offsets) == 0)
{
break;
}
rbNode = _rbTree.GetNext(rbNode);
}
}
private BTreePage NewPage(BTreeNode treeNode)
{
BTreePage result = _freeNode;
if (result == null)
{
result = new BTreePage(treeNode, _maxCount, _stream, _factoryKey);
}
else
{
result.SetPageData(treeNode, _maxCount, _factoryKey);
_freeNode = null;
}
return(result);
}
public void Merge(BTreePage rightPage)
{
int offset;
ProcessDeferredUpdates();
rightPage.ProcessDeferredUpdates();
rightPage.SetPosition(0);
for (int i = 0; i < rightPage._rightBound; ++i)
{
IFixedLengthKey key = rightPage.MemoryReadNext(out offset);
MemoryWrite(key, offset, _rightBound++);
}
_treeNode.SetNewCount(_rightBound);
rightPage._treeNode.SetNewCount(0);
_modified = rightPage._modified = true;
}
public override void SearchForRange(IFixedLengthKey beginKey, IFixedLengthKey endKey, ArrayList keys_offsets)
{
_searchNode.ChangeMinKey(beginKey, 0);
RBNodeBase rbNode = _rbTree.GetMaximumLess(_searchNode);
if (rbNode == null)
{
rbNode = _rbTree.GetMinimumNode();
}
while (rbNode != null && ((BTreeNode)rbNode.Key).MinKey.CompareTo(endKey) <= 0)
{
BTreePage page = PreparePage((BTreeNode)rbNode.Key);
page.SearchForRange(beginKey, endKey, keys_offsets);
rbNode = _rbTree.GetNext(rbNode);
}
}
public override void InsertKey(IFixedLengthKey key, int offset)
{
_count++;
RBNodeBase rbNode;
BTreeNode foundNode = SearchBTreeNode(key, offset, out rbNode);
if (foundNode == null)
{
if (_rbTree.Count == 0)
{
BTreeNode newNode = new BTreeNode(key.FactoryMethod(), offset, GetOffsetForNewPage());
_rbTree.RB_Insert(newNode);
BTreePage page = NewPage(newNode);
page.InsertKey(key, offset);
page.Write();
_cache.CacheObject(newNode.PageOffset, page);
return;
}
else
{
RBNodeBase rbMinNode = _rbTree.GetMinimumNode();
foundNode = (BTreeNode)rbMinNode.Key;
}
}
else
{
BTreePage page = PreparePage(foundNode);
if (page.Full())
{
float splitFactor = (_rbTree.GetNext(rbNode) == null) ? 0.875f : 0.5f;
BTreePage splittedPage = page.Split(key, offset, GetOffsetForNewPage(), splitFactor);
_rbTree.RB_Insert(splittedPage.BTreeNode);
splittedPage.Write();
_cache.CacheObject(splittedPage.BTreeNode.PageOffset, splittedPage);
}
else
{
page.InsertKey(key, offset);
}
}
}
private void _cache_ObjectRemoved(object sender, ObjectCacheEventArgs e)
{
_freeNode = (BTreePage)e.Object;
_freeNode.Write();
}
