The Most Evil Code Ever « Last Ray of Hope

19Mar/08Off

The Most Evil Code Ever

I have just created quite possibly the most evil code to mankind, its an abomination. However it did double my FPS.

Basically, I thought to myself "a class is basically just a structure, and its functions are basically the same function but with a pointer to the class at the beginning, so why can't I just have a pointer to a function within the class, and the class pointer and combine the to for function callbacks, but on a generic level, only have the base class structure known". And so thats what I set out to do, to test if it would work.

Now instead of calling an OnEvent function that is pure virtual in the base class, I can call the functions directly, skipping the middleman. It compiles on g++ and visual studio 9.

Source code

//
//
#include <iostream>
 
//
//
class IBase
{
	public:
		IBase()
		{
		}
 
		virtual ~IBase()
		{
		}
 
		int testno( const int j )
		{
			return 3;
		}
};
 
//
//
class clsDerived : public IBase
{
	public:
		clsDerived()
			:
			IBase()
		{
		}
 
		int test( const int i )
		{
			return i;
		}
};
 
//
//
class clsMyDerive : public IBase
{
	public:
		clsMyDerive()
			:
			IBase()
		{
		}
 
		virtual ~clsMyDerive()
		{
		}
 
		virtual int tested( const int i )
		{
			return -i;
		}
};
 
//
//
class clsMyD : public clsMyDerive
{
	public:
		clsMyD()
			:
			clsMyDerive()
		{
		}
 
		int testy( const int i )
		{
			return ~i;
		}
 
		int tested( const int i )
		{
			return -1 + 1;
		}
};
 
//
//
typedef int (IBase::*_FN_CLSGAME)( const int );
 
//
//
int main()
{
	IBase * test = new clsDerived();
	IBase * test2 = new clsMyDerive();
	IBase * test3 = new clsMyD();
	_FN_CLSGAME q;
 
	q = reinterpret_cast<_FN_CLSGAME>( &clsDerived::test );
	std::cout << "Test 1: %d" << (test->*q)(12) << std::endl;
 
	q = reinterpret_cast<_FN_CLSGAME>( &clsMyDerive::tested );
	std::cout << "Test 2: %d" << (test2->*q)(12) << std::endl;
 
	q = reinterpret_cast<_FN_CLSGAME>( &clsMyDerive::tested );
	std::cout << "Test 3: %d" << (test3->*q)(12) << std::endl;
 
	return 0;
}