SharedPtr.h

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// Copyright (C) 2002-2017, Open Design Alliance (the "Alliance"). 
// All rights reserved. 
// 
// This software and its documentation and related materials are owned by 
// the Alliance. The software may only be incorporated into application 
// programs owned by members of the Alliance, subject to a signed 
// Membership Agreement and Supplemental Software License Agreement with the
// Alliance. The structure and organization of this software are the valuable  
// trade secrets of the Alliance and its suppliers. The software is also 
// protected by copyright law and international treaty provisions. Application  
// programs incorporating this software must include the following statement 
// with their copyright notices:
//   
//   This application incorporates Teigha(R) software pursuant to a license 
//   agreement with Open Design Alliance.
//   Teigha(R) Copyright (C) 2002-2017 by Open Design Alliance. 
//   All rights reserved.
//
// By use of this software, its documentation or related materials, you 
// acknowledge and accept the above terms.
 
 
#ifndef _SharedPtr_h_Included
#define _SharedPtr_h_Included
 
#include "TD_PackPush.h"
 
#include "OdaCommon.h"
#include "OdAlloc.h"
 
template <class T> class OdSharedPtr
{
public:
 
  OdSharedPtr() : _reference(0), _refCount(0) {}
  
  OdSharedPtr(T* pObject) : _refCount(0)
  { 
    if ((_reference = pObject) != 0)
    {
      _refCount = (int*)::odrxAlloc(sizeof(int*));
      *_refCount = 1;
    }
  }
  
  OdSharedPtr(const OdSharedPtr& other) 
  {
    _reference = other._reference;
    _refCount = other._refCount;
    if (_refCount)
    {
      ++*_refCount;
    }
  }
 
  ~OdSharedPtr()
  {
    if (_refCount && !--*_refCount)
    {
      delete _reference;
      odrxFree(_refCount);
    }
  }
 
  OdSharedPtr& operator=(const OdSharedPtr &other)
  {
    if (_reference != other._reference)
    {
      if (_refCount && !--*_refCount)
      {
        odrxFree(_refCount);
        delete _reference;
      }
 
      _reference = other._reference;
      _refCount = other._refCount;
      if (_refCount)
      {
        ++*_refCount;
      }
    }
#ifdef _DEBUG
    else if (_reference != 0)
    {
      // there can't be independent shared pointers on the same object
      ODA_ASSERT_ONCE(_refCount == other._refCount);
      // if the counters are the same - do nothing (the assignment is no-op)
    }
#endif // _DEBUG
    return *this;
  }
 
  T* operator->() { return _reference; }
 
  T* get() { return _reference; }
  
  const T* get() const { return _reference; }
  
  operator T*() { return _reference; }
  operator const T*() const { return _reference; }
  
  const T* operator->() const { return _reference; }
  
  T& operator*(){ return *_reference; }
  
  const T& operator*() const { return *_reference; }
 
  bool isNull() const {return _reference == 0;}
 
  T* detach()
  {
    if (!_refCount)
      return 0;
    if (*_refCount > 1)
    {
      ODA_FAIL();
    }
    odrxFree(_refCount);
    _refCount = 0;
    T* ret = _reference;
    _reference = 0;
    return ret;
  }
  int refCount() const
  {
    return _refCount ? *_refCount : 0;
  }
private: 
  T* _reference;
  int* _refCount;
};
 
#include "TD_PackPop.h"
 
#endif // _SharedPtr_h_Included