/////////////////////////////////////////////////////////////////////////////// 
// Copyright (C) 2002-2025, 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 Open Design Alliance software pursuant to a license 
//   agreement with Open Design Alliance.
//   Open Design Alliance Copyright (C) 2002-2025 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 _ODSTACK_H_
#define _ODSTACK_H_

#include "TD_PackPush.h"

template <class T> class OdStackItem;
template <class T> class OdStack;
template <class T> class OdCachingStack;

/** \details

    <group Other_Classes> 
*/
template <class T>
class OdStackItem : public T
{
  friend class OdStack<T>;
  friend class OdCachingStack<T>;
protected:
  OdStackItem* m_pUnder;
  inline OdStackItem(OdStackItem* pUnder, const T& val)
    : T(val), m_pUnder(pUnder) { }
  inline OdStackItem(OdStackItem* pUnder, T&& val)
    : T(std::move(val)), m_pUnder(pUnder) { }
  inline OdStackItem(OdStackItem* pUnder) : m_pUnder(pUnder) { }
};

/** \details

    <group Other_Classes> 
*/
template <class T>
class OdStack
{
  typedef OdStackItem<T> TItem;
public:
  TItem* m_pTop;
  inline OdStack() : m_pTop(0) { }
  inline void push(const T& inVal)
  {
    m_pTop = new TItem(m_pTop, inVal);
  }
  inline void push(T&& inVal)
  {
    m_pTop = new TItem(m_pTop, std::move(inVal));
  }
  inline T* push()
  {
    m_pTop = new TItem(m_pTop);
    return top();
  }
  inline void pop(T& outVal)
  {
    ODA_ASSERT(m_pTop); // pop from empty stack
    outVal = *m_pTop;
    pop();
  }

  inline const T* top() const { return m_pTop; }
  inline T* top() { return m_pTop; }

  inline void pop()
  {
    TItem* pTop = m_pTop;
    ODA_ASSERT(pTop); // pop from empty stack
    m_pTop = pTop->m_pUnder;
    delete pTop;
  }

  inline ~OdStack()
  {
    while(m_pTop)
    {
      pop();
    }
  }

  inline T* beforeTop() const 
  { 
    ODA_ASSERT(m_pTop);
    return m_pTop->m_pUnder;
  }

  bool empty()const { return m_pTop == 0; }
  
  size_t size() const
  {
    size_t n = 0;
    for ( TItem* p = m_pTop; p; p = p->m_pUnder)
      ++n;
    return n;
  }
};

/** \details

    <group Other_Classes>
*/
template <class T>
class OdCachingStack : public OdStack<T>
{
  protected:
    typedef OdStack<T> Base;
    typedef OdStackItem<T> StackItem;
    StackItem *m_pCache;
  protected:
    StackItem *getItem(StackItem *pUnder)
    {
      if (m_pCache)
      {
        StackItem *pItem = m_pCache;
        m_pCache = m_pCache->m_pUnder;
        pItem->m_pUnder = pUnder;
        return pItem;
      }
      return new StackItem(pUnder);
    }
    void freeItems(StackItem *&pItems)
    {
      while (pItems)
      {
        StackItem *pItem = pItems;
        pItems = pItem->m_pUnder;
        delete pItem;
      }
    }
  public:
    inline OdCachingStack() : m_pCache(nullptr) { }
    inline ~OdCachingStack()
    {
      freeItems(Base::m_pTop);
      freeItems(m_pCache);
    }

    inline void push(const T& inVal)
    { *static_cast<T*>(Base::m_pTop = getItem(Base::m_pTop)) = inVal; }
    inline void push(T&& inVal)
    { *static_cast<T*>(Base::m_pTop = getItem(Base::m_pTop)) = std::move(inVal); }
    inline T* push()
    { return Base::m_pTop = getItem(Base::m_pTop); }

    inline void pop()
    { StackItem *pTop = Base::m_pTop;
      ODA_ASSERT(pTop); // pop from empty stack
      Base::m_pTop = pTop->m_pUnder;
      pTop->m_pUnder = m_pCache;
      m_pCache = pTop;
    }
    inline void pop(T& outVal)
    { ODA_ASSERT(Base::m_pTop); // pop from empty stack
      outVal = *Base::m_pTop;
      pop();
    }

    inline void clearCache()
    {
      freeItems(m_pCache);
    }
};

#include "TD_PackPop.h"

#endif //#ifndef _ODSTACK_H_