Function Pointer Member?

[high6]

I am trying to emulate this assembly in C++ (to make it more readable then a hacky inline assembly).

MOV EAX,DWORD PTR DS:[5D91B4]
PUSH ESI
LEA ECX,DWORD PTR DS:[EAX+89C08]
CALL 0047F3F8

So I have this psuedo code

	class MAIN
	{
	public:
		class FUNCLIST
		{
		public:
			bool (* FuncListContains)(int idx,bool) = (bool (*)(int,bool))0x0047EE03;
			int FuncListGetItem(int idx)
			{	
				return idx*2;
			}
		};
		FUNCLIST* FuncList = (FUNCLIST*)(this+0x00089C08);
	};
	MAIN* Main = (MAIN*)0x005D91B4;

Of course this doesn't work because the function pointer isn't static.

Is there anyway to set the function pointer as a constant but keeping it as a member?

Summary:

I am injecting a dll and I want to have that assembly above as C++ so I can easily call it from my dll without a hacky inline assembly segment.

[Killboy]

If I understood you correctly, this should work:

	class FUNCLIST
	{
	public:
			bool (* FuncListContains)(int idx,bool);
		// ....
	};
FUNCLIST::FuncListContains = (bool (*)(int,bool))0x0047EE03;

Why can't you set it to static anyway?

I'm not sure if the above actually works, I think it only does with statics.

However, you can init vars in the constructor:

		class FUNCLIST
		{
		public:
			bool (* FuncListContains)(int idx,bool)= (bool (*)(int,bool))0x0047EE03;
			int FuncListGetItem(int idx)
			{	
				return idx*2;
			}
			FUNCLIST() : FuncListContains((bool (*)(int,bool))0x0047EE03) {};
		};

[high6]

"Why can't you set it to static anyway?"

Because, I need it to set "ECX" ("this" in C++) to the address of the classes data.

Is there any way to not use contructors? And ya the top snippet only works if it is static.

[high6]

Still not satisfied with this way but I think it will work.

static const int FuncListContainsAddr = 0x0047EE03;
bool FuncListContains(int a, int B)
{
	return ((bool (*)(int,bool))FuncListContainsAddr)(a,B);
}

Edited April 20, 2009 by high6

[high6]

I guess I will have to do it like that unless I can declare a constant function pointer in a class. Forgot that a function pointer stores the destination so changing the location of "this" would break it.

[high6]

Almost works, just need to figure out how to set FuncListContains to 0x0047EE03.

	class MAIN
	{
	public:
		char bump1[0x00089C08];
		class FUNCLIST
		{
		public:
			bool FuncListContains(int idx,bool b)
 			{
 				return ((bool (*)(int,bool))0x0047EE03)(idx,b);
 			}
			int FuncListGetItem(int idx)
			{	
				return idx*2;
			}
		};
		FUNCLIST* FuncList;
	};
	static MAIN* Main = (MAIN*)0x005D91B4;

Would making "FuncListContains" virtual allow me to set it's address?

[high6]

why does this work

bool FuncListContains(int idx,bool b)
			{
				return ((bool (*)(int,bool))0x0047EE03)(idx,b);
			}

But not this

bool FuncListContains(int idx,bool b)
			{
				return ((bool (FUNCLIST::*)(int,bool))0x0047EE03)(idx,b);
			}

?

It says that it cannot typecast an int to "bool (FUNCLIST::*)(int,bool)".

Basically I want to call an address as a member without having a function pointer stored that takes up space in the classes memory.