btree.h

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C头文件 代码 · 共 120 行

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*
*                            Open Watcom Project
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*    This file contains Original Code and/or Modifications of Original
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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#ifndef __BTREE_H_INCLUDED__

#include "btreebas.h"

template <class Key_T, class Obj_T> class BTreeNodeBase;

template< class Obj_T >
class BTreeBase {
public:
                        BTreeBase() : _entries( 0 ), _primary( NULL ){};
    virtual             ~BTreeBase();

            uint        entries() const { return _entries; };   // num elements
    virtual bool        unlock( Obj_T * ){ return FALSE; }
    virtual bool        lock( Obj_T * ){ return FALSE; }
            bool        operator== ( const BTreeBase& other ) const {
                            return &other == this;
                        }

            friend class BTree; // so can access protected members thru ptr

protected:
    virtual void        insert( Obj_T * ) = 0;
    virtual void        remove( Obj_T * ) = 0;
    virtual void        update( Obj_T * ) = 0;

            void        incEntries() { _entries += 1; };
            void        decEntries() { _entries -= 1; };
            void        setPrimary( BTreeBase * n );
            BTreeBase * getPrimary() { return _primary; };

            WCPtrSList<BTreeBase> *     getIndicies() { return _indicies; };

private:
    uint                    _entries;
    BTreeBase *             _primary;
    WCPtrSList<BTreeBase> * _indicies;
};

template< class Key_T, class Obj_T >
class BTreeRootedBase : public BTreeBase< Obj_T > {

public:
    virtual BTreeNodeBase< Key_T, Obj_T> * getRoot() = 0;
};

template < class Key_T, class Obj_T >
class BTree : public BTreeRootedBase< Key_T, Obj_T > {

public:
                BTree( uint keyOrder, uint objOrder,
                        BTreeBase<Obj_T> * primary = NULL );
                ~BTree();

            // find an element, return a pointer to a locked object
            Obj_T *     find( const Key_T & key );

            // insert an element, updating all indices
            void        insert( Obj_T * obj );
            void        remove( Obj_T * obj );

            // unlock a found object
            bool        unlock( Obj_T * );
            bool        lock( Obj_T * );

    virtual BTreeNodeBase< Key_T, Obj_T> * getRoot() { return _root; }

            #if INSTRUMENTS
            void    print();
            #endif

protected:
            void    update( Obj_T * obj );

private:
    BTreeNodeBase<Key_T,Obj_T> *    _root;
    uint                            _keyOrder;
    uint                            _objOrder;

    #if INSTRUMENTS
    int                 _locks;
    int                 _unlocks;
    #endif
};

#define __BTREE_H_INCLUDED__
#endif