aria2/src/SimpleRandomizer.h

/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * 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 2 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#ifndef _D_SIMPLE_RANDOMIZER_H_
#define _D_SIMPLE_RANDOMIZER_H_

#include "Randomizer.h"
#include "a2time.h"
#include <stdlib.h>

namespace aria2 {

class SimpleRandomizer : public Randomizer {
private:
  static RandomizerHandle randomizer;

  SimpleRandomizer() {}
public:

  static RandomizerHandle getInstance() {
    if(randomizer.isNull()) {
      randomizer.reset(new SimpleRandomizer());
    }
    return randomizer;
  }
  
  static void init() {
    srand(time(0));
  }

  virtual ~SimpleRandomizer() {}

  virtual long int getRandomNumber() {
    return rand();
  }

  virtual long int getMaxRandomNumber() {
      return RAND_MAX;
  }

  /**
   * Returns random number in [0, to).
   */
  virtual long int getRandomNumber(long int to)
  {
    return(int32_t)(((double)to)*getRandomNumber()/(getMaxRandomNumber()+1.0));
  }
};

} // namespace aria2

#endif // _D_SIMPLE_RANDOMIZER_H_