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Custom memory manger operator new


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#1 3DModelerMan   Members   -  Reputation: 1021

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Posted 30 April 2013 - 07:54 PM

I've written a custom memory management system similar to this one http://www.gamedev.net/page/resources/_/technical/general-programming/c-custom-memory-allocation-r3010

 

Right now I'm trying to make it so that anything of a certain class has allocations and deallocations handled by that memory manager. But since operator new and operator delete are static, there's no way to keep a pointer to the allocater around so that the allocater can free whatever it allocated in the first place when delete was called. What would be the best way to hook new and delete into my memory allocater system? 



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#2 Hodgman   Moderators   -  Reputation: 30950

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Posted 30 April 2013 - 09:46 PM

You can add extra parameters to operator new, and then you can store a pointer to the allocator inside the allocation itself so that operator delete can access it:
struct Allocator
{
	int name;
	static void* Alloc( uint size  ) { return malloc(size); }
	static void  Free ( void* data ) { return free(data); }
};
class Myclass
{
	struct Block
	{
		Allocator* a;
	};
public:
	void* operator new(size_t size, Allocator& a)
	{//store the allocator pointer in a header, return the memory after the header
		Block* data = (Block*)a.Alloc(size + sizeof(Block));
		data->a = &a;
		return data+1;
	}
	void operator delete(void* memory)
	{//go back a few bytes to find the start of the header
		Block* data = ((Block*)memory)-1;
		data->a->Free( data );
	}
};

Allocator alloc = { 42 };
Myclass* object = new(alloc) Myclass;//extra parameters to new
delete object;


#3 3DModelerMan   Members   -  Reputation: 1021

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Posted 01 May 2013 - 07:56 AM

Thanks. That should work perfect.






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