smartptr.h

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/*
 * smartptr.h
 *
 * Smart pointer template class.
 *
 * Portable Tools Library
 *
 * Copyright (c) 1993-1998 Equivalence Pty. Ltd.
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is Portable Windows Library.
 *
 * The Initial Developer of the Original Code is Equivalence Pty. Ltd.
 *
 * Portions are Copyright (C) 1993 Free Software Foundation, Inc.
 * All Rights Reserved.
 *
 * Contributor(s): ______________________________________.
 *
 */

#ifndef PTLIB_SMARTPTR_H
#define PTLIB_SMARTPTR_H

#include <ptlib.h>
#include <ptlib/object.h>

// "Smart" pointers.

class PSmartObject : public PObject
{
  PCLASSINFO(PSmartObject, PObject);

  protected:
    PSmartObject()
      : referenceCount(1)
    { }

    PSmartObject(const PSmartObject & other)
      : PObject(other)
      , referenceCount(1)
    { }

    atomic<uint32_t> referenceCount;

  private:
    void operator=(const PSmartObject&) { }

  friend class PSmartPointer;
};


class PSmartPointer : public PObject
{
  PCLASSINFO(PSmartPointer, PObject);

  public:
    PSmartPointer(
      PSmartObject * obj = NULL   
    ) { object = obj; }

    PSmartPointer(
      const PSmartPointer & ptr  
    );

    virtual ~PSmartPointer();

    PSmartPointer & operator=(
      const PSmartPointer & ptr  
    );

    virtual Comparison Compare(
      const PObject & obj   
    ) const;

    PBoolean IsNULL() const { return object == NULL; }

    PSmartObject * GetObject() const { return object; }

  protected:
    // Member variables
    PSmartObject * object;
};


template <class T> class PSmartPtr : public PSmartPointer
{
  PCLASSINFO(PSmartPtr, PSmartPointer);
  public:
    PSmartPtr(T * ptr = NULL)
      : PSmartPointer(ptr) { }

    T * operator->() const
      { return (T *)PAssertNULL(object); }

    T & operator*() const
      { return *(T *)PAssertNULL(object); }

    operator T*() const
      { return (T *)object; }
};


#endif // PTLIB_SMARTPTR_H


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