Function CheckAddToTodoSet

src/signal.cpp:213–221

* Perform some operations before adding data into Todo set * The new and reverse direction is removed from _globset, because we are sure * it doesn't need to be checked again * Also, remove reverse direction from _tbdset * This is the 'core' part so the graph searching won't enter any tile twice * * @param t1 tile we are entering * @param d1 direction (tile side) we are entering * @param t

 * @return false iff reverse direction was in Todo set
 */
static inline bool CheckAddToTodoSet(TileIndex t1, DiagDirection d1, TileIndex t2, DiagDirection d2)
{
	_globset.Remove(t1, d1); // it can be in Global but not in Todo
	_globset.Remove(t2, d2); // remove in all cases

	assert(!_tbdset.IsIn(t1, d1)); // it really shouldn't be there already

	return !_tbdset.Remove(t2, d2);
}


/**