C4ObjectPtr.h

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/*
 * OpenClonk, http://www.openclonk.org
 *
 * Copyright (c) 2010-2016, The OpenClonk Team and contributors
 *
 * Distributed under the terms of the ISC license; see accompanying file
 * "COPYING" for details.
 *
 * "Clonk" is a registered trademark of Matthes Bender, used with permission.
 * See accompanying file "TRADEMARK" for details.
 *
 * To redistribute this file separately, substitute the full license texts
 * for the above references.
 */
 
/* A convenient way to (de)serialize object pointers */
 
#ifndef INC_C4ObjectPtr
#define INC_C4ObjectPtr
 
// An enumerable C4Object pointer
class C4ObjectPtr
{
public:
    // For use with mkNamingAdapt because simply 0 becomes 0 (the int)
    // which makes correct template deduction fail. This constant is a
    // denumerated null pointer which can be repeatedly denumerated.
    static const C4ObjectPtr Null;
 
    C4ObjectPtr() = default; // uninitialized
 
    C4ObjectPtr(C4Object* pObj)
#ifndef NDEBUG
            : fDenumerated(true)
#endif
    {
        data.ptr = pObj;
    }
 
    void CompileFunc(StdCompiler* pComp);
    void DenumeratePointers();
 
    bool operator!() const { assert(fDenumerated); return !data.ptr; }
    bool operator==(C4Object* other) const { assert(fDenumerated); return data.ptr == other; }
    bool operator==(const C4ObjectPtr& other) const { assert(fDenumerated == other.fDenumerated); return data.ptr == other.data.ptr; }
    bool operator!=(C4Object* other) const { assert(fDenumerated); return data.ptr != other; }
    bool operator!=(const C4ObjectPtr& other) const { assert(fDenumerated == other.fDenumerated); return data.ptr != other.data.ptr; }
 
    C4ObjectPtr operator=(C4Object* object)
    {
#ifndef NDEBUG
        fDenumerated = true;
#endif
        data.ptr = object;
        return *this;
    }
 
    C4Object& operator*() const { assert(fDenumerated); return *data.ptr; }
    C4Object* operator->() const { assert(fDenumerated); return data.ptr; }
    operator C4Object*() const { assert(fDenumerated); return data.ptr; }
 
protected:
#ifndef NDEBUG
    bool fDenumerated;
#endif
 
    union
    {
        C4Object* ptr;
        intptr_t nptr; // needs to have same size as ptr for operator== to work when enumerated
    } data;
};
 
#endif