+ // Tries to find a source bus and an offset to it that would give
+ // a consistent offset for the rest of the mappings in this bus.
+ // Returns -1 for the bus (the first element) if no consistent offset
+ // can be found.
+ std::pair<int, int> guess_offset(unsigned bus_idx);
+ bool bus_is_empty(unsigned bus_idx);
+
+ void update_guess_button_state();
+ int find_focus_bus();
+