/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file pointerToVoid.h
 * @author drose
 * @date 2004-09-27
 */

#ifndef POINTERTOVOID_H
#define POINTERTOVOID_H

#include "pandabase.h"
#include "pnotify.h"
#include "memoryBase.h"
#include "atomicAdjust.h"

#include <algorithm>

/**
 * This is the non-template part of the base class for PointerTo and
 * ConstPointerTo.  It is necessary so we can keep a pointer to a non-template
 * class within the ReferenceCount object, to implement weak reference
 * pointers--we need to have something to clean up when the ReferenceCount
 * object destructs.
 *
 * This is the base class for PointerToBase<T>.
 */
class EXPCL_PANDA_EXPRESS PointerToVoid : public MemoryBase {
protected:
  constexpr PointerToVoid() noexcept = default;
  //INLINE ~PointerToVoid();

private:
  PointerToVoid(const PointerToVoid &copy) = delete;

PUBLISHED:
  constexpr bool is_null() const;
  INLINE size_t get_hash() const;

public:
  // These comparison functions are common to all things PointerTo, so they're
  // defined up here.
  INLINE bool operator < (const void *other) const;
  INLINE bool operator < (const PointerToVoid &other) const;

  INLINE bool operator == (const PointerToVoid &other) const;
  INLINE bool operator != (const PointerToVoid &other) const;

  INLINE void swap(PointerToVoid &other) noexcept;

protected:
  // Within the PointerToVoid class, we only store a void pointer.  This is
  // actually the (To *) pointer that is typecast to (void *) from the derived
  // template classes.

  // It is tempting to try to store a (ReferenceCount *) pointer here, but
  // this is not useful because it prohibits defining, say, PT(PandaNode), or
  // a PointerTo any class that inherits virtually from ReferenceCount.  (You
  // can't downcast past a virtual inheritance level, but you can always
  // cross-cast from a void pointer.)
  AtomicAdjust::Pointer _void_ptr = nullptr;
};

#include "pointerToVoid.I"

#endif