SmartPtr.h

#ifndef _theplu_yat_utility_smart_ptr_
#define _theplu_yat_utility_smart_ptr_

// $Id: SmartPtr.h 3992 2020-09-17 03:42:03Z peter $

/*
  Copyright (C) 2008 Jari Häkkinen, Peter Johansson
  Copyright (C) 2012, 2014, 2020 Peter Johansson

  This file is part of the yat library, http://dev.thep.lu.se/yat

  The yat library 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.

  The yat library 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 yat. If not, see <http://www.gnu.org/licenses/>.
*/

#include "yat_assert.h"

namespace theplu {
namespace yat {
namespace utility {

  template<typename T>
  class SmartPtr
  {
  public:
    explicit SmartPtr(T* p=NULL, bool owner=true)
      : pointee_(p)
    {
      if (owner)
        ref_count_ = new unsigned int(1);
      else
        ref_count_ = NULL;
    }

    SmartPtr(const SmartPtr& other)
      : pointee_(other.pointee_), ref_count_(other.ref_count_)
    {
      if (ref_count_)
        ++(*ref_count_);
    }

    virtual ~SmartPtr()
    {
      detach();
    }

    SmartPtr& operator=(const SmartPtr& rhs)
    {
      if (pointee_!=rhs.pointee_){
        detach();
        pointee_ = rhs.pointee_;
        ref_count_= rhs.ref_count_;
        if (ref_count_)
          ++(*ref_count_);
      }
      return *this;
    }

    T* operator->(void) const
    {
      return pointee_;
    }

    T& operator*(void) const
    {
      return *pointee_;
    }

  private:
    T* pointee_;
    unsigned int* ref_count_;

    void detach(void)
    {
      if (ref_count_)
        if (!--(*ref_count_))
          delete pointee_;
    }
  };

}}} // of namespace utility, yat, and theplu
#endif