SaveState.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 _ODSAVESTATE_INCLUDED_
#define _ODSAVESTATE_INCLUDED_
 
#include "TD_PackPush.h"
 
template <class T>
class OdSaveState
{
  T&  m_val;        // Variable
  T   m_oldValue;   // Old value
public:
  OdSaveState( T& variable )
    : m_val( variable )
  {
    m_oldValue = m_val;
  }
  OdSaveState( T& variable, const T& newValue )
    : m_val( variable )
  {
    m_oldValue = m_val;
    m_val = newValue;
  }
  ~OdSaveState()
  {
    m_val = m_oldValue;
  }
  operator const T&() const
  {
    return m_oldValue;
  }
};
 
#ifdef __hpux
#define OdSaveStateFlagDef(type, flag, name, flags) \
  const type _##name##Flag = flag; \
  OdSaveStateFlagImpl<type, _##name##Flag> name(flags)
#define OdSaveStateFlag(type, flag, name, flags, newVal) \
  const type _##name##Flag = flag; \
  OdSaveStateFlagImpl<type, _##name##Flag> name(flags, newVal)
#else
#define OdSaveStateFlagDef(type, flag, name, flags) \
  OdSaveStateFlagImpl<type, flag> name(flags)
#define OdSaveStateFlag(type, flag, name, flags, newVal) \
  OdSaveStateFlagImpl<type, flag> name(flags, newVal)
#endif
 
template <class T, T flag>
class OdSaveStateFlagImpl
{
  T&   m_val;       // Variable
  bool m_oldValue;  // Old flag value
public:
  OdSaveStateFlagImpl(T& variable): m_val( variable )
  {
    m_oldValue = GETBIT(m_val, flag);
  }
  OdSaveStateFlagImpl(T& variable, bool bNewValue): m_val( variable )
  {
    m_oldValue = GETBIT(m_val, flag);
    SETBIT(m_val, flag, bNewValue);
  }
  ~OdSaveStateFlagImpl()
  {
    SETBIT(m_val, flag, m_oldValue);
  }
  operator bool() const
  {
    return m_oldValue;
  }
};
 
#include "TD_PackPop.h"
 
#endif //#ifndef _ODSAVESTATE_INCLUDED_