defer c++11

defer.hpp

// src: http://www.gingerbill.org/article/defer-in-cpp.html

// This code requires C++11 features such as move semantics
#pragma once
#include <functional>

namespace Impl
{
template <typename Func>
struct Defer
{
	Func func;
	Defer(Func&& func)
	: func(std::forward<Func>(func))
	{
	}

	~Defer()
	{
		func();
	}
};

template <typename Func>
Defer<Func> deferFunc(Func&& func)
{
	return Defer<Func>(std::forward<Func>(func));
}

#define DEFER_1(x, y) x##y
#define DEFER_2(x, y) DEFER_1(x, y)
#define DEFER_3(x) DEFER_2(x, __COUNTER__)
#define defer(code) auto DEFER_3(_defer_) = Impl::deferFunc([&](){code;});

} // namespace Impl

/* 
// example:

void someFunc()
{
	FILE* file = fopen("filename.ext", "rb");
	if (file == nullptr)
		return;
	defer(fclose(file));

	u8* buffer = (u8*)allocate(64 * sizeof(u8));
	if (buffer == nullptr)
		return; // fclose is called automatically
	defer(deallocate(buffer));

	defer({
		printf("You can even defer ");
		printf("an entire block too!");
	});

	// Do whatever...
}
*/