C++ interop, abstract struct problem

[RSY]

Hmm, something seems to be very wrong, here what i got so far

``` D
     struct IAllocator
     { }
     struct DefaultAllocator
     {
         // BASE --------------------------
         IAllocator base = IAllocator();
         alias base this;
         //--------------------------------

         ubyte* m_small_allocations = null;
         void*[4] m_free_lists;
         uint m_page_count = 0;
         Mutex m_mutex;
     }


     void preinit(ref IAllocator allocator, bool load_renderdoc);
```

The problem is the allocator data seems to be corrupted, it 
crashes on the C++ side when calling preinit


IAllocator is empty, but it doesn't get optimized as the wiki 
say, since the size of DefaultAllocator is 64 bytes on the C++ 
side, and 56 bytes on D side, i get 64 bytes with the definition 
above

Does anyone have an idea, did i translate the struct wrong?


```C++
struct LUMIX_ENGINE_API IAllocator {
	virtual ~IAllocator() {}
	virtual bool isDebug() const { return false; }

	virtual void* allocate(size_t size) = 0;
	virtual void deallocate(void* ptr) = 0;
	virtual void* reallocate(void* ptr, size_t size) = 0;

	virtual void* allocate_aligned(size_t size, size_t align) = 0;
	virtual void deallocate_aligned(void* ptr) = 0;
	virtual void* reallocate_aligned(void* ptr, size_t size, size_t 
align) = 0;

	template <typename T> void deleteObject(T* ptr) {
		if (ptr)
		{
			ptr->~T();
			deallocate_aligned(ptr);
		}
	}
};

```

and for DefaultAllocator

```c++
struct LUMIX_ENGINE_API DefaultAllocator final : IAllocator {
	struct Page;

	DefaultAllocator();
	~DefaultAllocator();

	void* allocate(size_t n) override;
	void deallocate(void* p) override;
	void* reallocate(void* ptr, size_t size) override;
	void* allocate_aligned(size_t size, size_t align) override;
	void deallocate_aligned(void* ptr) override;
	void* reallocate_aligned(void* ptr, size_t size, size_t align) 
override;

	u8* m_small_allocations = nullptr;
	Page* m_free_lists[4];
	u32 m_page_count = 0;
	Mutex m_mutex;
};

```


For Mutex:

```c++
struct alignas(8) LUMIX_ENGINE_API Mutex {
	friend struct ConditionVariable;
	
	Mutex();
	Mutex(const Mutex&) = delete;
	~Mutex();

	void enter();
	void exit();

private:
	#ifdef _WIN32
		u8 data[8];
	#else
		pthread_mutex_t mutex;
	#endif
};

```