typedef hash_map<u32,UObjectRef> hs;
	typedef hs::iterator OH_iterator;

	....

	hs hash;
	OH_iterator reap_iterator;

	...

	while (...)
	{
		OH_iterator save_iterator = reap_iterator;
		++reap_iterator;

		if (...)
		{
			hash.erase( save_iterator );
		}

		if (reap_iterator == hash.end())
		{
			reap_iterator = hash.begin();
			if (reap_iterator == hash.end())
				break;
		}
	}