/*

 *

 * (C) 2017-26 - ntop.org

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 3 of the License, or

 * (at your option) any later version.

 *

 * 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

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software Foundation,

 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 *

 */

#ifndef _FREQUENT_STRING_ITEMS_H_

#define _FREQUENT_STRING_ITEMS_H_

#include "ntop_includes.h"

/* https://resources.sei.cmu.edu/asset_files/Presentation/2010_017_001_49763.pdf

 */

/* *************************************** */

class FrequentStringItems {

 private:

  u_int32_t max_items, max_items_threshold;

  std::map<std::string, u_int32_t> q;

  Mutex m;

  bool thread_safe;

  void prune();

 public:

  FrequentStringItems(u_int32_t _max_items, bool _thread_safe = true) {

    max_items = _max_items, max_items_threshold = 2 * _max_items,

    thread_safe = _thread_safe;

  }

  inline u_int32_t getSize() { return q.size(); };

  void add(char* key, u_int32_t value);

  char* json(u_int32_t max_num_items = (u_int32_t)-1);

  inline void clear() { q.clear(); }

};

#endif /* _FREQUENT_STRING_ITEMS_H_ */