/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2005,2006 INRIA

 * All rights reserved.

 *

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

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * 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

 *

 * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 */

#ifndef PTR_H

#define PTR_H

#include <stdint.h>

#include "assert.h"

namespace ns3 {

/**

 * \brief smart pointer class similar to boost::intrusive_ptr

 *

 * This smart-pointer class assumes that the underlying

 * type provides a pair of Ref and Unref methods which are

 * expected to increment and decrement the internal refcount

 * of the object instance.

 *

 * This implementation allows you to manipulate the smart pointer

 * as if it was a normal pointer: you can compare it with zero,

 * compare it against other pointers, assign zero to it, etc.

 *

 * It is possible to extract the raw pointer from this

 * smart pointer with the GetPointer and PeekPointer methods.

 *

 * If you want to store a newed object into a smart pointer,

 * we recommend you to use the MakeNewObject template functions

 * to create the object and store it in a smart pointer to avoid

 * memory leaks. These functions are really small conveniance

 * functions and their goal is just is save you a small

 * bit of typing.

 */

template <typename T>

class Ptr 

{

private:

  T *m_ptr;

  class Tester {

  private:

    void operator delete (void *);

  };

  friend class Ptr<const T>;

  template <typename U>

  friend U *GetPointer (const Ptr<U> &p);

  template <typename U>

  friend U *PeekPointer (const Ptr<U> &p);

  void Acquire (void) const;

public:

  /**

   * Create an empty smart pointer

   */

  Ptr ();

  /**

   * \param ptr raw pointer to manage

   *

   * Create a smart pointer which points to the

   * input raw pointer. This method takes ownershipt

   * of the input raw pointer. That is, the smart pointer

   * becomes responsible for calling delete on the

   * raw pointer when needed.

   */

  Ptr (T *ptr);

  Ptr (Ptr const&o);

  // allow conversions from T to T const.

  template <typename U>

  Ptr (Ptr<U> const &o);

  ~Ptr () ;

  Ptr<T> &operator = (Ptr const& o);

  T *operator -> () const;

  T *operator -> ();

  // allow if (!sp)

  bool operator! ();

  // allow if (sp)

  operator Tester * () const;

};

template <typename T>

Ptr<T> MakeNewObject (void);

template <typename T, typename T1>

Ptr<T> MakeNewObject (T1 a1);

template <typename T, typename T1, typename T2>

Ptr<T> MakeNewObject (T1 a1, T2 a2);

template <typename T, typename T1, typename T2, typename T3>

Ptr<T> MakeNewObject (T1 a1, T2 a2, T3 a3);

template <typename T, typename T1, typename T2, typename T3, typename T4>

Ptr<T> MakeNewObject (T1 a1, T2 a2, T3 a3, T4 a4);

template <typename T, typename T1, typename T2, typename T3, typename T4, typename T5>

Ptr<T> MakeNewObject (T1 a1, T2 a2, T3 a3, T4 a4, T5 a5);

template <typename T, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>

Ptr<T> MakeNewObject (T1 a1, T2 a2, T3 a3, T4 a4, T5 a5, T6 a6);

template <typename T, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7>

Ptr<T> MakeNewObject (T1 a1, T2 a2, T3 a3, T4 a4, T5 a5, T6 a6, T7 a7);

/**

 * \return the pointer managed by this smart pointer.

 *

 * The underlying refcount is not incremented prior

 * to returning to the caller so the caller is not

 * responsible for calling Unref himself.

 */

template <typename T>

T * PeekPointer (const Ptr<T> &p);

/**

 * \return the pointer managed by this smart pointer.

 *

 * The underlying refcount is incremented prior

 * to returning to the caller so the caller is

 * responsible for calling Unref himself.

 */

template <typename T>

T * GetPointer (const Ptr<T> &p);

// allow if (sp == 0)

template <typename T1, typename T2>

bool operator == (Ptr<T1> const &lhs, T2 const *rhs);

// allow if (0 == sp)

template <typename T1, typename T2>

bool operator == (T1 const *lhs, Ptr<T2> &rhs);

// allow if (sp != 0)

template <typename T1, typename T2>

bool operator != (Ptr<T1> const &lhs, T2 const *rhs);

// allow if (0 != sp)

template <typename T1, typename T2>

bool operator != (T1 const *lhs, Ptr<T2> &rhs);

// allow if (sp0 == sp1)

template <typename T1, typename T2>

bool operator == (Ptr<T1> const &lhs, Ptr<T2> const &rhs);

// allow if (sp0 != sp1)

template <typename T1, typename T2>

bool operator != (Ptr<T1> const &lhs, Ptr<T2> const &rhs);

template <typename T1, typename T2>

Ptr<T1> const_pointer_cast (Ptr<T2> const&p);

} // namespace ns3

namespace ns3 {

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

   *  friend non-member function implementations

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

template <typename T>

Ptr<T> MakeNewObject (void)

{

  T *obj = new T ();

  Ptr<T> p = obj;

  obj->Unref ();

  return p;

}

template <typename T, typename T1>

Ptr<T> MakeNewObject (T1 a1)

{

  T *obj = new T (a1);

  Ptr<T> p = obj;

  obj->Unref ();

  return p;

}

template <typename T, typename T1, typename T2>

Ptr<T> MakeNewObject (T1 a1, T2 a2)

{

  T *obj = new T (a1, a2);

  Ptr<T> p = obj;

  obj->Unref ();

  return p;

}

template <typename T, typename T1, typename T2, typename T3>

Ptr<T> MakeNewObject (T1 a1, T2 a2, T3 a3)

{

  T *obj = new T (a1, a2, a3);

  Ptr<T> p = obj;

  obj->Unref ();

  return p;

}

template <typename T, typename T1, typename T2, typename T3, typename T4>

Ptr<T> MakeNewObject (T1 a1, T2 a2, T3 a3, T4 a4)

{

  T *obj = new T (a1, a2, a3, a4);

  Ptr<T> p = obj;

  obj->Unref ();

  return p;

}

template <typename T, typename T1, typename T2, typename T3, typename T4, typename T5>

Ptr<T> MakeNewObject (T1 a1, T2 a2, T3 a3, T4 a4, T5 a5)

{

  T *obj = new T (a1, a2, a3, a4, a5);

  Ptr<T> p = obj;

  obj->Unref ();

  return p;

}

template <typename T, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>

Ptr<T> MakeNewObject (T1 a1, T2 a2, T3 a3, T4 a4, T5 a5, T6 a6)

{

  T *obj = new T (a1, a2, a3, a4, a5, a6);

  Ptr<T> p = obj;

  obj->Unref ();

  return p;

}

template <typename T, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7>

Ptr<T> MakeNewObject (T1 a1, T2 a2, T3 a3, T4 a4, T5 a5, T6 a6, T7 a7)

{

  T *obj = new T (a1, a2, a3, a4, a5, a6, a7);

  Ptr<T> p = obj;

  obj->Unref ();

  return p;

}

template <typename T>

T * PeekPointer (const Ptr<T> &p)

{

  return p.m_ptr;

}

template <typename T>

T * GetPointer (const Ptr<T> &p)

{

  p.Acquire ();

  return p.m_ptr;

}

template <typename T1, typename T2>

bool 

operator == (Ptr<T1> const &lhs, T2 const *rhs)

{

  return PeekPointer (lhs) == rhs;

}

template <typename T1, typename T2>

bool 

operator == (T1 const *lhs, Ptr<T2> &rhs)

{

  return lhs == PeekPointer (rhs);

}

template <typename T1, typename T2>

bool 

operator != (Ptr<T1> const &lhs, T2 const *rhs)

{

  return PeekPointer (lhs) != rhs;

}

template <typename T1, typename T2>

bool 

operator != (T1 const *lhs, Ptr<T2> &rhs)

{

  return lhs != PeekPointer (rhs);

}

template <typename T1, typename T2>

bool 

operator == (Ptr<T1> const &lhs, Ptr<T2> const &rhs)

{

  return PeekPointer (lhs) == PeekPointer (rhs);

}

template <typename T1, typename T2>

bool 

operator != (Ptr<T1> const &lhs, Ptr<T2> const &rhs)

{

  return PeekPointer (lhs) != PeekPointer (rhs);

}

template <typename T1, typename T2>

Ptr<T1>

const_pointer_cast (Ptr<T2> const&p)

{

  return Ptr<T1> (const_cast<T1 *> (PeekPointer (p)));

}

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

 *      Member method implementations.

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

template <typename T>

void 

Ptr<T>::Acquire (void) const

{

  if (m_ptr != 0)

    {

      m_ptr->Ref ();

    }  

}

template <typename T>

Ptr<T>::Ptr ()

  : m_ptr (0)

{}

template <typename T>

Ptr<T>::Ptr (T *ptr) 

  : m_ptr (ptr)

{

  Acquire ();

}

template <typename T>

Ptr<T>::Ptr (Ptr const&o) 

  : m_ptr (PeekPointer (o))

{

  Acquire ();

}

template <typename T>

template <typename U>

Ptr<T>::Ptr (Ptr<U> const &o)

  : m_ptr (PeekPointer (o))

{

  Acquire ();

}

template <typename T>

Ptr<T>::~Ptr () 

{

  if (m_ptr != 0) 

    {

      m_ptr->Unref();

    }

}

template <typename T>

Ptr<T> &

Ptr<T>::operator = (Ptr const& o) 

{

  if (&o == this)

    {

      return *this;

    }

  if (m_ptr != 0) 

    {

      m_ptr->Unref();

    }

  m_ptr = o.m_ptr;

  Acquire ();

  return *this;

}

template <typename T>

T *

Ptr<T>::operator -> () 

{

  return m_ptr;

}

template <typename T>

T *

Ptr<T>::operator -> () const

{

  return m_ptr;

}

template <typename T>

bool 

Ptr<T>::operator! () 

{

  return m_ptr == 0;

}

template <typename T>

Ptr<T>::operator Tester * () const

{

  if (m_ptr == 0) 

    {

      return 0;

    }

  static Tester test;

  return &test;

}

}; // namespace ns3

#endif /* PTR_H */