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//
// Database.h
//
// Database: Class which defines the interface to a generic,
// simple database.
//
// Part of the ht://Dig package <http://www.htdig.org/>
// Copyright (c) 1999-2004 The ht://Dig Group
// For copyright details, see the file COPYING in your distribution
// or the GNU Library General Public License (LGPL) version 2 or later
// <http://www.gnu.org/copyleft/lgpl.html>
//
// $Id: Database.h,v 1.15 2004/05/28 13:15:20 lha Exp $
//
#ifndef _Database_h_
#define _Database_h_
#include "Object.h"
#include "htString.h"
#include <db.h>
// Database Types
// defined in db.h
// #define DB_BTREE 1
// #define DB_HASH 2
#ifndef GDBM_HASH
#define GDBM_HASH 2
#endif
class Database : public Object
{
//
// Make sure no one can actually create an object of this type or
// the derived types. The static getDatabaseInstance() method needs to be
// used.
//
protected:
Database();
public:
~Database();
//
// Since the contructor is protected, the only way to actually get
// a Database object is through the following class method.
// The idea here is that the particular type of database used by
// all the programs is to be defined in one place.
//
static Database *getDatabaseInstance(DBTYPE type);
//
// Common interface
//
virtual int OpenReadWrite(const char *filename, int mode = 0666) = 0;
virtual int OpenRead(const char *filename) = 0;
void SetCompare(int (*func)(const DBT *a, const DBT *b)) { _compare = func; }
void SetPrefix(size_t (*func)(const DBT *a, const DBT *b)) { _prefix = func; }
virtual int Close() = 0;
virtual int Put(const String &key, const String &data) = 0;
virtual int Get(const String &key, String &data) = 0;
virtual int Exists(const String &key) = 0;
virtual int Delete(const String &key) = 0;
virtual void Start_Get() = 0;
virtual char *Get_Next() { String item; String key; return Get_Next(item, key); }
virtual char *Get_Next(String &item) { String key; return Get_Next(item, key); }
virtual char *Get_Next(String &item, String &key) = 0;
virtual void Start_Seq(const String& str) = 0;
virtual char *Get_Next_Seq() { return Get_Next(); }
protected:
int isOpen;
DB *dbp; // database
DBC *dbcp; // cursor
String skey; // Next key to search for iterator
String data; // Next data to return for iterator
String lkey; // Contains the last key returned by iterator
DB_ENV *dbenv; // database enviroment
int (*_compare)(const DBT *a, const DBT *b); // Key comparison
size_t (*_prefix)(const DBT *a, const DBT *b); // Key reduction
int seqrc;
int seqerr;
DBTYPE db_type;
};
#endif
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