/* -*- 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::shared_ptr
*
* This smart-pointer class is supposed to be used to manage
* heap-allocated objects: when it decides it does not need
* the object it references, it invokes operator delete on it.
* 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, etc. However, the only
* operation we are careful to avoid is the conversion back to
* raw pointers: if you need to convert back, you need to invoke
* the Ptr<T>::Remove method which returns a raw pointer and
* makes the smart pointer forget about the raw pointer.
*/
template <typename T>
class Ptr
{
private:
T *m_ptr;
uint32_t *m_count;
class Tester {
private:
void operator delete (void *);
};
static uint32_t *AllocCount (void);
static void DeallocCount (uint32_t *count);
friend class Ptr<const T>;
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 const& operator * () const;
T *operator -> () const;
T *operator -> ();
// allow if (!sp)
bool operator! ();
// allow if (sp)
operator Tester * () const;
// allow if (sp == 0)
template <typename T1, typename T2>
inline friend bool operator == (Ptr<T1> const &lhs, T2 const *rhs);
// allow if (0 == sp)
template <typename T1, typename T2>
inline friend bool operator == (T1 const *lhs, Ptr<T2> &rhs);
// allow if (sp != 0)
template <typename T1, typename T2>
inline friend bool operator != (Ptr<T1> const &lhs, T2 const *rhs);
// allow if (0 != sp)
template <typename T1, typename T2>
inline friend bool operator != (T1 const *lhs, Ptr<T2> &rhs);
template <typename T1, typename T2>
inline friend Ptr<T1> const_pointer_cast (Ptr<T2> const&p);
/**
* \returns raw pointer
*
* It is a programming error to invoke this method when
* the reference count of the smart pointer is not one.
* If you try to do it anyway, an assert will be triggered.
* If asserts are disabled, bad things will happen.
* Once you have successfully called Ptr<T>::Remove on
* a smart pointer, the smart pointer will forget
* about the raw pointer and will stop managing it. As such,
* you, as the caller, become responsible for invoking
* operator delete on the returned raw pointer.
*/
T *Remove (void);
};
template <typename T>
uint32_t *
Ptr<T>::AllocCount (void)
{
return new uint32_t [1] ();
}
template <typename T>
void
Ptr<T>::DeallocCount (uint32_t *count)
{
delete [] count;
}
template <typename T>
Ptr<T>::Ptr ()
: m_ptr (0),
m_count (0)
{}
template <typename T>
Ptr<T>::Ptr (T *ptr)
: m_ptr (ptr),
m_count (0)
{
if (m_ptr != 0)
{
m_count = Ptr::AllocCount ();
*m_count = 1;
}
}
template <typename T>
Ptr<T>::Ptr (Ptr const&o)
: m_ptr (o.m_ptr),
m_count (0)
{
if (m_ptr != 0)
{
m_count = o.m_count;
(*m_count)++;
}
}
template <typename T>
template <typename U>
Ptr<T>::Ptr (Ptr<U> const &o)
: m_ptr (o.m_ptr),
m_count (0)
{
if (m_ptr != 0)
{
NS_ASSERT (o.m_ptr != 0);
m_count = o.m_count;
(*m_count)++;
}
}
template <typename T>
Ptr<T>::~Ptr ()
{
if (m_ptr != 0)
{
(*m_count)--;
if ((*m_count) == 0)
{
delete m_ptr;
Ptr::DeallocCount (m_count);
}
}
}
template <typename T>
Ptr<T> &
Ptr<T>::operator = (Ptr const& o)
{
if (&o == this)
return *this;
if (m_ptr != 0)
{
(*m_count)--;
if ((*m_count) == 0)
{
delete m_ptr;
Ptr::DeallocCount (m_count);
}
}
m_ptr = o.m_ptr;
if (m_ptr != 0)
{
m_count = o.m_count;
(*m_count)++;
}
return *this;
}
template <typename T>
T const&
Ptr<T>::operator * () const
{
return *m_ptr;
}
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;
}
template <typename T>
T *
Ptr<T>::Remove (void)
{
if (m_ptr == 0)
{
return (T *) 0;
}
else
{
NS_ASSERT ((*m_count) == 1);
Ptr::DeallocCount (m_count);
T *retval = m_ptr;
m_ptr = 0;
return retval;
}
}
// non-member friend functions.
template <typename T1, typename T2>
bool
operator == (Ptr<T1> const &lhs, T2 const *rhs)
{
return lhs.m_ptr == rhs;
}
template <typename T1, typename T2>
bool
operator == (T1 const *lhs, Ptr<T2> &rhs)
{
return lhs == rhs.m_ptr;
}
template <typename T1, typename T2>
bool
operator != (Ptr<T1> const &lhs, T2 const *rhs)
{
return lhs.m_ptr != rhs;
}
template <typename T1, typename T2>
bool
operator != (T1 const *lhs, Ptr<T2> &rhs)
{
return lhs != rhs.m_ptr;
}
template <typename T1, typename T2>
Ptr<T1>
const_pointer_cast (Ptr<T2> const&p)
{
return Ptr<T1> (const_cast<T1 *> (p.m_ptr));
}
}; // namespace ns3
#endif /* PTR_H */