142 lines
4.9 KiB
C++

/*
** Command & Conquer Generals(tm)
** Copyright 2025 Electronic Arts Inc.
**
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation, either version 3 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
////////////////////////////////////////////////////////////////////////////////
// //
// (c) 2001-2003 Electronic Arts Inc. //
// //
////////////////////////////////////////////////////////////////////////////////
// Override.h /////////////////////////////////////////////////////////////////////////////////////
// Electronic Arts Pacific
// Do Not Distribute
#pragma once
#ifndef _OVERRIDE_H_
#define _OVERRIDE_H_
#include "Common/Overridable.h"
/*
An OVERRIDE is a replacement for a pointer of its contained type, ie, rather than containing
a LocomotorTemplate*, you would contain an OVERRIDE<LocomotorTemplate>.
OVERRIDE pretends in all ways (dereference via *, -> and casting to type*) to be a type*, so
there should be very little code that needs to be rewritten to work with these.
In order to make something overridable, these are the steps:
1) Make the desired class derive from Overridable.
2) Make the container class contain an instance of OVERRIDE<Type>
3) Make the newOverride function (wherever an override is new'd) request the overridables lastOverride,
to ensure that no leaks are created.
See LocomotorTemplate for an example.
*/
template <class T> class OVERRIDE
{
public:
// Provide useful constructores to go from a T* to an OVERRIDE<T>
OVERRIDE(const T *overridable = NULL);
// Copy constructor
OVERRIDE(OVERRIDE<T> &overridable);
// Operator= for copying from another OVERRIDE and T*
__inline OVERRIDE &operator=( const OVERRIDE<T>& override );
__inline OVERRIDE &operator=( const T* overridable );
// these are the methods which we can use to access data in a pointer. (Dereference*, ->, and cast
// to T*). They are all overloaded to recurse to the lowest override and use that.
__inline const T *operator->( void ) const; // overload const ->
__inline const T *operator*( void ) const; // overload const *(dereference operator)
__inline operator const T*( ) const; // overload casting to (const T*)
// this is useful in case you want to get the pointer that this object is actually looking at.
__inline const T *getNonOverloadedPointer( void ) const;
private:
// Because OVERRIDE is meant to live on the object and not in the store, it currently contains
// a constant pointer. We could change this if it seems weird.
const T *m_overridable;
};
//-------------------------------------------------------------------------------------------------
template <class T>
OVERRIDE<T>::OVERRIDE(const T *overridable)
{
m_overridable = overridable;
}
//-------------------------------------------------------------------------------------------------
template <class T>
OVERRIDE<T>::OVERRIDE(OVERRIDE<T> &overridable)
{
m_overridable = overridable.m_overridable;
}
//-------------------------------------------------------------------------------------------------
template <class T>
OVERRIDE<T> &OVERRIDE<T>::operator=( const OVERRIDE<T>& override )
{
m_overridable = override.m_overridable;
return *this;
}
//-------------------------------------------------------------------------------------------------
template <class T>
OVERRIDE<T> &OVERRIDE<T>::operator=(const T* overridable)
{
m_overridable = overridable;
return *this;
}
//-------------------------------------------------------------------------------------------------
template <class T>
const T *OVERRIDE<T>::operator->() const
{
if (!m_overridable)
return NULL;
return (T*) m_overridable->getFinalOverride();
}
//-------------------------------------------------------------------------------------------------
template <class T>
const T *OVERRIDE<T>::operator*() const
{
if (!m_overridable)
return NULL;
return (T*) m_overridable->getFinalOverride();
}
//-------------------------------------------------------------------------------------------------
template <class T>
const T *OVERRIDE<T>::getNonOverloadedPointer( void ) const
{
return (T*) m_overridable;
}
//-------------------------------------------------------------------------------------------------
template <class T>
OVERRIDE<T>::operator const T*( ) const
{
return operator*();
}
#endif /* _OVERRIDE_H_ */