C++ coroutines

#ifndef FIBER_HPP
#define FIBER_HPP

#define _WIN32_WINNT 0x0400

#include <cassert>
#include <windows.h>

#define yield { if(GetFiberData()) reinterpret_cast<Win32::Fiber*>(GetFiberData)->Pause(); }

namespace Win32
{
	enum FiberState
	{
		FiberCreated,
		FiberRunning,
		FiberStopping,
		FiberStopped
	};

	class Fiber
	{
	public:
		explicit Fiber(void (* fiberProc)(void*), void* arg = 0) :
			ParentHandle(0),
			FiberProc(fiberProc),
			Argument(arg),
			State(FiberCreated)
		{
			Handle = CreateFiber(0, Fiber::FiberBounceProc, reinterpret_cast<void*>(this));
		}

		void* GetParentHandle() const
		{
			return ParentHandle;
		}

		void Pause()
		{
			if(GetCurrentFiber() == Handle)
			{
				SwitchToFiber(ParentHandle);
			}
		}

		void Run()
		{
			if(ParentHandle == 0)
				ParentHandle = GetCurrentFiber();

			SwitchToFiber(Handle);
		}

	private:
		static void WINAPI FiberBounceProc(void* arg)
		{
			Fiber* fiber = reinterpret_cast<Fiber*>(arg);
			fiber->State = FiberRunning;

			try
			{
				fiber->FiberProc(fiber->Argument);
			}
			catch(...)
			{
				DebugBreak();
			}

			fiber->State = FiberStopping;
			DeleteFiber(fiber->Handle);
			fiber->State = FiberStopped;
		}

	private:
		void*		Handle;
		void*		ParentHandle;
		void		(*FiberProc)(void*);
		void*		Argument;
		FiberState	State;

	};

}