gistcursor.h

此文件包含了在linux下实现tpr-tree索引的源代码

// -*- Mode: C++ -*-
//--------------------------------------------------------------------
//        GiSTcursor.h
//        ------------
//
//        GiST - Generalized Search Tree 
//        June 2001 release, Aalborg University
//        
//        This file is a revised version of a part of the original 
//        libGiST release (version  0.9beta1)     
//        Copyright (c) 1996, Regents of the University of California
//

#ifndef GISTCURSOR_H
#define GISTCURSOR_H

#include "GiSTdefs.h"
#include "GiSTentry.h"
#include "GiSTpredicate.h"
#include "GiSTlist.h"
#include "GiSTpath.h"

class GiST;

//-------------------------------------------------------
//  GiSTcursor
//

class GiSTcursor : public GiSTobject
{
  public:
    GiSTcursor(const GiST& gist, const GiSTpredicate& query);
    virtual GiSTentry* Next();
    void Flush();
    GiSTobjid  IsA() const { return GISTCURSOR_CLASS; }
    ~GiSTcursor();
    const GiSTpath& Path() const;
    const GiST* Tree() const { return &gist; }

  protected:
    const GiST&    gist;
    GiSTpath       path;
    GiSTlist<GiSTentry*> stack;
    int            first;
    GiSTpredicate* query;
    int            lastlevel;
};

//-------------------------------------------------------
//  GiSTdebugCursor - Cursor that traverses all the tree
//

class GiSTdebugCursor : public GiSTcursor
{
  public:
    GiSTdebugCursor(const GiST& gist, const GiSTpredicate& query) :
                   GiSTcursor(gist, truePredicate), 
                   realQuery((GiSTpredicate*)query.Copy()) {}
    ~GiSTdebugCursor() { delete realQuery; }
    GiSTentry* Next();        
  protected:
    GiSTpredicate* realQuery;
};

#endif