BTreeNode.h

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/*
// $Id: //open/dev/fennel/btree/BTreeNode.h#9 $
// Fennel is a library of data storage and processing components.
// Copyright (C) 2005-2009 The Eigenbase Project
// Copyright (C) 2005-2009 SQLstream, Inc.
// Copyright (C) 2005-2009 LucidEra, Inc.
// Portions Copyright (C) 1999-2009 John V. Sichi
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 of the License, or (at your option)
// any later version approved by The Eigenbase Project.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef Fennel_BTreeNode_Included
#define Fennel_BTreeNode_Included

#include "fennel/segment/SegPageLock.h"

FENNEL_BEGIN_NAMESPACE

struct FENNEL_BTREE_EXPORT BTreeNode
    : public StoredNode
{
    static const MagicNumber MAGIC_NUMBER = 0x9d4ec481f86aa93eLL;

    PageId rightSibling;

    uint nEntries;

    uint height;

    uint cbTotalFree;

    uint cbCompactFree;

    // NOTE:  interpretation of the data is dependent on the node's height in
    // the tree and the way in which the tree is defined.
    // See BTreeNodeAccessor.

    PBuffer getDataForWrite()
    {
        return reinterpret_cast<PBuffer>(this + 1);
    }

    PConstBuffer getDataForRead() const
    {
        return reinterpret_cast<PConstBuffer>(this + 1);
    }
};

typedef SegNodeLock<BTreeNode> BTreePageLock;

FENNEL_END_NAMESPACE

#endif

// End BTreeNode.h

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