BTreeNode.h

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00001 /*
00002 // $Id: //open/dev/fennel/btree/BTreeNode.h#9 $
00003 // Fennel is a library of data storage and processing components.
00004 // Copyright (C) 2005-2009 The Eigenbase Project
00005 // Copyright (C) 2005-2009 SQLstream, Inc.
00006 // Copyright (C) 2005-2009 LucidEra, Inc.
00007 // Portions Copyright (C) 1999-2009 John V. Sichi
00008 //
00009 // This program is free software; you can redistribute it and/or modify it
00010 // under the terms of the GNU General Public License as published by the Free
00011 // Software Foundation; either version 2 of the License, or (at your option)
00012 // any later version approved by The Eigenbase Project.
00013 //
00014 // This program is distributed in the hope that it will be useful,
00015 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00016 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00017 // GNU General Public License for more details.
00018 //
00019 // You should have received a copy of the GNU General Public License
00020 // along with this program; if not, write to the Free Software
00021 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00022 */
00023 
00024 #ifndef Fennel_BTreeNode_Included
00025 #define Fennel_BTreeNode_Included
00026 
00027 #include "fennel/segment/SegPageLock.h"
00028 
00029 FENNEL_BEGIN_NAMESPACE
00030 
00034 struct FENNEL_BTREE_EXPORT BTreeNode
00035     : public StoredNode
00036 {
00037     static const MagicNumber MAGIC_NUMBER = 0x9d4ec481f86aa93eLL;
00038 
00046     PageId rightSibling;
00047 
00051     uint nEntries;
00052 
00056     uint height;
00057 
00061     uint cbTotalFree;
00062 
00067     uint cbCompactFree;
00068 
00069     // NOTE:  interpretation of the data is dependent on the node's height in
00070     // the tree and the way in which the tree is defined.
00071     // See BTreeNodeAccessor.
00072 
00076     PBuffer getDataForWrite()
00077     {
00078         return reinterpret_cast<PBuffer>(this + 1);
00079     }
00080 
00084     PConstBuffer getDataForRead() const
00085     {
00086         return reinterpret_cast<PConstBuffer>(this + 1);
00087     }
00088 };
00089 
00090 typedef SegNodeLock<BTreeNode> BTreePageLock;
00091 
00092 FENNEL_END_NAMESPACE
00093 
00094 #endif
00095 
00096 // End BTreeNode.h

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