///###////////////////////////////////////////////////////////////////////////
//
// Burton Computer Corporation
// http://www.burton-computer.com
// http://www.cooldevtools.com
// $Id: FrequencyDBImpl_bdb.h 272 2007-01-06 19:37:27Z brian $
//
// Copyright (C) 2007 Burton Computer Corporation
// ALL RIGHTS RESERVED
//
// This program is open source software; you can redistribute it
// and/or modify it under the terms of the Q Public License (QPL)
// version 1.0. Use of this software in whole or in part, including
// linking it (modified or unmodified) into other programs is
// subject to the terms of the QPL.
//
// 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
// Q Public License for more details.
//
// You should have received a copy of the Q Public License
// along with this program; see the file LICENSE.txt.  If not, visit
// the Burton Computer Corporation or CoolDevTools web site
// QPL pages at:
//
//    http://www.burton-computer.com/qpl.html
//    http://www.cooldevtools.com/qpl.html
//

#ifndef _FrequencyDBImpl_bdb_h
#define _FrequencyDBImpl_bdb_h

#ifdef USE_DB

#include <db.h>

#include "FrequencyDBImpl.h"

class File;
class LockFile;

class FrequencyDBImpl_bdb : public FrequencyDBImpl
{
public:
  FrequencyDBImpl_bdb();
  ~FrequencyDBImpl_bdb();

  bool open(const string &filename,
            bool read_only,
            int create_mode);
  void close();

  void flush();

  void writeWord(const string &word,
                 const WordData &word_data);

  bool readWord(const string &word,
                WordData &word_data);

  bool firstWord(string &word,
                 WordData &counts);

  bool nextWord(string &word,
                WordData &counts);

  string getDatabaseType() const;

  void sweepOutOldTerms(const CleanupManager &cleanman);

  static FrequencyDBImpl *factory(const DatabaseConfig *);

private:
  bool firstWord(string &word,
                 WordData &counts,
                 bool read_only);

  bool loadKey(DBT &key,
               string &word,
               WordData &counts) const;

  bool loadKey(DBT &key,
               WordData &counts) const;

  bool openDatabase(const File &db_file,
                    bool read_only,
                    int create_mode);

  bool openEnvironment(const File &db_file,
                       bool read_only,
                       int create_mode);

  void closeCursor();
  void closeDatabase();
  void closeEnvironment();

private:
  /// Not implemented.
  FrequencyDBImpl_bdb(const FrequencyDBImpl_bdb &);

  /// Not implemented.
  FrequencyDBImpl_bdb& operator=(const FrequencyDBImpl_bdb &);

private:
  bool m_isReadOnly;
  DB_ENV *m_env;
  DB *m_file;
  DBC *m_cursor;
};

#endif // USE_DB

#endif // _FrequencyDBImpl_bdb_h