gistfilecache.h

此文件包含了在linux下实现tpr-tree索引的源代码

// -*- Mode: C++ -*-
//--------------------------------------------------------------------
//        GiSTfileCache.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 GISTFILECACHE_H
#define GISTFILECACHE_H

#include "GiSTfile.h"


//--------------------------------------------------------------------
//  GiSTfileCahce is a simple cahced storage class for GiSTs to work over
//  UNIX/NT files.
//

#define DEF_FILECACHE_SIZE  9000       // 9000 pages in cache 
#define DEF_FILECACHE_SIZE2 10000       // 10000 pages in total

class GiSTfileCache : public GiSTfile
{ 
 public:
   GiSTfileCache() : GiSTfile(), lenPageNums(0), buffer(NULL) {}
   ~GiSTfileCache() { if (buffer) delete buffer; }
 
   void     Create(const char *filename);
   void     Open  (const char *filename);
   void     Close ();
   void     Reset ();  

   void     Read    (GiSTpage page, char *buf);
   void     Write   (GiSTpage page, const char *buf);

 private:
   int      GetNewSlot(); 

   int      lookUp[DEF_FILECACHE_SIZE2];
   GiSTpage pageNums[DEF_FILECACHE_SIZE];
   char     dirty[DEF_FILECACHE_SIZE];
   int      lenPageNums;
   char    *buffer;    
};

#endif