149 lines
4.3 KiB
C++
149 lines
4.3 KiB
C++
/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
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/*
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* Copyright (c) 2007 Georgia Tech Research Corporation, INRIA
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation;
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Authors: George Riley <riley@ece.gatech.edu>
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* Gustavo Carneiro <gjcarneiro@gmail.com>,
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* Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
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*/
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#ifndef SIMPLE_REF_COUNT_H
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#define SIMPLE_REF_COUNT_H
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#include "empty.h"
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#include "default-deleter.h"
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#include "assert.h"
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#include <stdint.h>
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#include <limits>
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/**
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* \file
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* \ingroup ptr
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* Reference counting for smart pointers.
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*/
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namespace ns3 {
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/**
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* \ingroup ptr
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* \brief A template-based reference counting class
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*
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* This template can be used to give reference-counting powers
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* to a class. This template does not require this class to
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* have a virtual destructor or a specific (or any) parent class.
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*
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* Note: if you are moving to this template from the RefCountBase class,
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* you need to be careful to mark appropriately your destructor virtual
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* if needed. i.e., if your class has subclasses, _do_ mark your destructor
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* virtual.
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*
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*
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* This template takes 3 arguments but only the first argument is
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* mandatory:
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*
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* \tparam T \explicit The typename of the subclass which derives
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* from this template class. Yes, this is weird but it's a
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* common C++ template pattern whose name is CRTP (Curiously
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* Recursive Template Pattern)
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* \tparam PARENT \explicit The typename of the parent of this template.
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* By default, this typename is "'ns3::empty'" which is an empty
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* class: compilers which implement the RBCO optimization (empty
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* base class optimization) will make this a no-op
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* \tparam DELETER \explicit The typename of a class which implements
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* a public static method named 'Delete'. This method will be called
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* whenever the SimpleRefCount template detects that no references
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* to the object it manages exist anymore.
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*
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* Interesting users of this class include ns3::Object as well as ns3::Packet.
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*/
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template <typename T, typename PARENT = empty, typename DELETER = DefaultDeleter<T> >
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class SimpleRefCount : public PARENT
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{
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public:
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/**
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* Constructor
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*/
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SimpleRefCount ()
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: m_count (1)
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{}
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/**
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* Copy constructor
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*/
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SimpleRefCount (const SimpleRefCount &o)
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: m_count (1)
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{}
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/**
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* Assignment
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*/
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SimpleRefCount &operator = (const SimpleRefCount &o)
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{
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return *this;
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}
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/**
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* Increment the reference count. This method should not be called
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* by user code. SimpleRefCount instances are expected to be used in
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* conjunction with the Ptr template which would make calling Ref
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* unnecessary and dangerous.
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*/
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inline void Ref (void) const
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{
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NS_ASSERT (m_count < std::numeric_limits<uint32_t>::max());
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m_count++;
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}
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/**
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* Decrement the reference count. This method should not be called
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* by user code. SimpleRefCount instances are expected to be used in
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* conjunction with the Ptr template which would make calling Ref
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* unnecessary and dangerous.
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*/
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inline void Unref (void) const
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{
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m_count--;
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if (m_count == 0)
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{
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DELETER::Delete (static_cast<T*> (const_cast<SimpleRefCount *> (this)));
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}
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}
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/**
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* Get the reference count of the object.
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* Normally not needed; for language bindings.
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*
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* \return The reference count.
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*/
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inline uint32_t GetReferenceCount (void) const
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{
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return m_count;
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}
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/**
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* Noop
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*/
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static void Cleanup (void) {}
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private:
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/**
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* The reference count.
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*
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* \internal
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* Note we make this mutable so that the const methods can still
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* change it.
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*/
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mutable uint32_t m_count;
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};
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} // namespace ns3
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#endif /* SIMPLE_REF_COUNT_H */
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