#ifndef COIN_SOELEMENT_H
#define COIN_SOELEMENT_H

/**************************************************************************\
 *
 *  This file is part of the Coin 3D visualization library.
 *  Copyright (C) 1998-2006 by Systems in Motion.  All rights reserved.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  ("GPL") version 2 as published by the Free Software Foundation.
 *  See the file LICENSE.GPL at the root directory of this source
 *  distribution for additional information about the GNU GPL.
 *
 *  For using Coin with software that can not be combined with the GNU
 *  GPL, and for taking advantage of the additional benefits of our
 *  support services, please contact Systems in Motion about acquiring
 *  a Coin Professional Edition License.
 *
 *  See http://www.coin3d.org/ for more information.
 *
 *  Systems in Motion, Postboks 1283, Pirsenteret, 7462 Trondheim, NORWAY.
 *  http://www.sim.no/  sales@sim.no  coin-support@coin3d.org
 *
\**************************************************************************/

#include <Inventor/SbBasic.h>
#include <Inventor/SoType.h>
#include <Inventor/misc/SoState.h>
#include <stdio.h>

class SoNode;

class COIN_DLL_API SoElement {
public:
  static void initClass(void);

  static SoType getClassTypeId(void);
  static int getClassStackIndex(void);
  const SoType getTypeId(void) const;
  int getStackIndex(void) const;

  virtual void init(SoState * state);

  virtual void push(SoState * state);
  virtual void pop(SoState * state, const SoElement * prevTopElement);

  virtual SbBool matches(const SoElement * element) const = 0;
  virtual SoElement * copyMatchInfo(void) const = 0;

  static void initElements(void); // only for base class (SoElement)

  static int getNumStackIndices(void);
  static SoType getIdFromStackIndex(const int stackIndex);

  void setDepth(const int depth);

  int getDepth(void) const;

  virtual void print(FILE * file = stdout) const;
  virtual ~SoElement();

protected:
  SoElement(void);
  static int classStackIndex;

  static SoElement * getElement(SoState * const state, const int stackIndex);
  static const SoElement * getConstElement(SoState * const state, const int stackIndex);
  
  void capture(SoState * const state) const;

  virtual void captureThis(SoState * state) const;

  void setTypeId(const SoType typeId);
  void setStackIndex(const int index);

  SoType typeId;
  int stackIndex;

  static int createStackIndex(const SoType id);
  static SoTypeList * stackToType;

  int depth;

  SoElement * getNextInStack(void) const;
  SoElement * getNextFree(void) const;

private:

  static SoType classTypeId;

  friend class SoState; // FIXME: bad design. 19990629 mortene.
  static void cleanup(void);
  SoElement * nextup;
  SoElement * nextdown;
};

// inlined methods

inline SoElement *
SoElement::getElement(SoState * const state,
                      const int stackIndex)
{
  return state->getElement(stackIndex);
}

inline void 
SoElement::capture(SoState * const state) const
{
  if (state->isCacheOpen()) this->captureThis(state);
}

inline const SoElement *
SoElement::getConstElement(SoState * const state,
                           const int stackIndex)
{
  const SoElement * element = state->getConstElement(stackIndex);
  element->capture(state);
  return element;
}

#endif // !COIN_SOELEMENT_H
