| // Copyright 2010 Christophe Henry |
| // henry UNDERSCORE christophe AT hotmail DOT com |
| // This is an extended version of the state machine available in the boost::mpl library |
| // Distributed under the same license as the original. |
| // Copyright for the original version: |
| // Copyright 2005 David Abrahams and Aleksey Gurtovoy. Distributed |
| // under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at |
| // http://www.boost.org/LICENSE_1_0.txt) |
| |
| #include <vector> |
| #include <iostream> |
| #include <boost/mpl/vector/vector50.hpp> |
| #include <boost/msm/back/state_machine.hpp> |
| #include <boost/msm/front/state_machine_def.hpp> |
| #include <boost/msm/back/tools.hpp> |
| |
| namespace msm = boost::msm; |
| namespace mpl = boost::mpl; |
| |
| namespace // Concrete FSM implementation |
| { |
| // events |
| struct play {}; |
| struct end_pause {}; |
| struct stop {}; |
| struct pause {}; |
| struct open_close {}; |
| struct NextSong {}; |
| // event which every other event can convert to |
| struct AllSongsPlayed |
| { |
| template <class Event> |
| AllSongsPlayed(Event const&){} |
| }; |
| struct PreviousSong {}; |
| struct error_found {}; |
| struct end_error {}; |
| |
| // Flags. Allow information about a property of the current state |
| struct CDLoaded {}; |
| struct FirstSongPlaying {}; |
| |
| // A "complicated" event type that carries some data. |
| enum DiskTypeEnum |
| { |
| DISK_CD=0, |
| DISK_DVD=1 |
| }; |
| struct cd_detected |
| { |
| cd_detected(DiskTypeEnum diskType): disc_type(diskType) {} |
| DiskTypeEnum disc_type; |
| }; |
| |
| // Concrete FSM implementation |
| struct player_ : public msm::front::state_machine_def<player_> |
| { |
| // The list of FSM states |
| struct Empty : public msm::front::state<> |
| { |
| typedef mpl::vector<play> deferred_events; |
| // every (optional) entry/exit methods get the event packed as boost::any. Not useful very often. |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "entering: Empty" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "leaving: Empty" << std::endl;} |
| }; |
| struct Open : public msm::front::state<> |
| { |
| typedef mpl::vector1<CDLoaded> flag_list; |
| typedef mpl::vector<play> deferred_events; |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "entering: Open" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "leaving: Open" << std::endl;} |
| }; |
| // a state needing a pointer to the containing state machine |
| // and using for this the non-default policy |
| // if policy used, set_sm_ptr is needed |
| struct Stopped : public msm::front::state<default_base_state,msm::front::sm_ptr> |
| { |
| // when stopped, the CD is loaded |
| typedef mpl::vector1<CDLoaded> flag_list; |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "entering: Stopped" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "leaving: Stopped" << std::endl;} |
| void set_sm_ptr(player_* pl){m_player=pl;} |
| player_* m_player; |
| }; |
| // the player state machine contains a state which is himself a state machine |
| // it demonstrates Shallow History: if the state gets activated with end_pause |
| // then it will remember the last active state and reactivate it |
| // also possible: AlwaysHistory, the last active state will always be reactivated |
| // or NoHistory, always restart from the initial state |
| struct Playing_ : public msm::front::state_machine_def<Playing_> |
| { |
| // when playing, the CD is loaded and we are in either pause or playing (duh) |
| typedef mpl::vector<CDLoaded> flag_list; |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "entering: Playing" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "leaving: Playing" << std::endl;} |
| |
| // The list of FSM states |
| struct Song1 : public msm::front::state<> |
| { |
| typedef mpl::vector1<FirstSongPlaying> flag_list; |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "starting: First song" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "finishing: First Song" << std::endl;} |
| }; |
| struct Song2 : public msm::front::state<> |
| { |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "starting: Second song" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "finishing: Second Song" << std::endl;} |
| }; |
| struct Song3 : public msm::front::state<> |
| { |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "starting: Third song" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "finishing: Third Song" << std::endl;} |
| }; |
| struct CDFinished : public msm::front::exit_pseudo_state<AllSongsPlayed> |
| { |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "entering: Playing::CDFinished" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "leaving: Playing::CDFinished" << std::endl;} |
| }; |
| // the initial state. Must be defined |
| typedef Song1 initial_state; |
| // transition actions |
| void start_next_song(NextSong const&) { std::cout << "Playing::start_next_song\n"; } |
| void start_prev_song(PreviousSong const&) { std::cout << "Playing::start_prev_song\n"; } |
| void all_songs_played(NextSong const&) { std::cout << "Playing::all_songs_played\n"; } |
| // guard conditions |
| |
| typedef Playing_ pl; // makes transition table cleaner |
| // Transition table for Playing |
| struct transition_table : mpl::vector< |
| // Start Event Next Action Guard |
| // +---------+---------------+------------+---------------------+----------------------+ |
| a_row < Song1 , NextSong , Song2 , &pl::start_next_song >, |
| a_row < Song2 , PreviousSong, Song1 , &pl::start_prev_song >, |
| a_row < Song2 , NextSong , Song3 , &pl::start_next_song >, |
| a_row < Song3 , PreviousSong, Song2 , &pl::start_prev_song >, |
| a_row < Song3 , NextSong , CDFinished , &pl::all_songs_played > |
| // +---------+---------------+---------+---------------------+----------------------+ |
| > {}; |
| // Replaces the default no-transition response. |
| template <class FSM,class Event> |
| void no_transition(Event const& e, FSM&,int state) |
| { |
| std::cout << "no transition from state " << state |
| << " on event " << typeid(e).name() << std::endl; |
| } |
| }; |
| typedef msm::back::state_machine<Playing_,msm::back::ShallowHistory<mpl::vector<end_pause> > > Playing; |
| |
| // the player state machine contains a state which is himself a state machine (2 of them, Playing and Paused) |
| struct Paused : public msm::front::state<> |
| { |
| typedef mpl::vector<CDLoaded> flag_list; |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "entering: Paused" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "leaving: Paused" << std::endl;} |
| }; |
| |
| struct AllOk : public msm::front::state<> |
| { |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "starting: AllOk" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "finishing: AllOk" << std::endl;} |
| }; |
| struct ErrorMode : //public msm::front::terminate_state<> |
| public msm::front::interrupt_state<end_error> |
| { |
| template <class Event,class FSM> |
| void on_entry(Event const&,FSM& ) {std::cout << "starting: ErrorMode" << std::endl;} |
| template <class Event,class FSM> |
| void on_exit(Event const&,FSM& ) {std::cout << "finishing: ErrorMode" << std::endl;} |
| }; |
| |
| // the initial state of the player SM. Must be defined |
| typedef mpl::vector<Empty,AllOk> initial_state; |
| |
| // transition actions |
| void start_playback(play const&) { std::cout << "player::start_playback\n"; } |
| void open_drawer(open_close const&) { std::cout << "player::open_drawer\n"; } |
| void close_drawer(open_close const&) { std::cout << "player::close_drawer\n"; } |
| void store_cd_info(cd_detected const&) |
| { |
| std::cout << "player::store_cd_info\n"; |
| // generate another event to test the queue |
| //cd.m_player.process_event(play()); |
| } |
| void stop_playback(stop const&) { std::cout << "player::stop_playback\n"; } |
| void end_playback (AllSongsPlayed const&) { std::cout << "player::end_playback\n"; } |
| void pause_playback(pause const&) { std::cout << "player::pause_playback\n"; } |
| void resume_playback(end_pause const&) { std::cout << "player::resume_playback\n"; } |
| void stop_and_open(open_close const&) { std::cout << "player::stop_and_open\n"; } |
| void stopped_again(stop const&){std::cout << "player::stopped_again\n";} |
| void report_error(error_found const&) {std::cout << "player::report_error\n";} |
| void report_end_error(end_error const&) {std::cout << "player::report_end_error\n";} |
| // guard conditions |
| bool good_disk_format(cd_detected const& evt) |
| { |
| // to test a guard condition, let's say we understand only CDs, not DVD |
| if (evt.disc_type != DISK_CD) |
| { |
| std::cout << "wrong disk, sorry" << std::endl; |
| return false; |
| } |
| return true; |
| } |
| |
| typedef player_ p; // makes transition table cleaner |
| |
| // Transition table for player |
| struct transition_table : mpl::vector< |
| // Start Event Next Action Guard |
| // +-------------+---------------+---------+---------------------+----------------------+ |
| a_row < Stopped , play , Playing , &p::start_playback >, |
| a_row < Stopped , open_close , Open , &p::open_drawer >, |
| a_row < Stopped , stop , Stopped , &p::stopped_again >, |
| // +-------------+---------------+---------+---------------------+----------------------+ |
| a_row < Open , open_close , Empty , &p::close_drawer >, |
| // +-------------+---------------+---------+---------------------+----------------------+ |
| a_row < Empty , open_close , Open , &p::open_drawer >, |
| row < Empty , cd_detected , Stopped , &p::store_cd_info ,&p::good_disk_format >, |
| // +-------------+---------------+---------+---------------------+----------------------+ |
| a_row < Playing , stop , Stopped , &p::stop_playback >, |
| a_row < Playing , pause , Paused , &p::pause_playback >, |
| a_row < Playing , open_close , Open , &p::stop_and_open >, |
| a_row < Playing::exit_pt< |
| Playing_::CDFinished> , AllSongsPlayed, Stopped , &p::end_playback >, |
| // +-------------+---------------+---------+---------------------+----------------------+ |
| a_row < Paused , end_pause , Playing , &p::resume_playback >, |
| a_row < Paused , stop , Stopped , &p::stop_playback >, |
| a_row < Paused , open_close , Open , &p::stop_and_open >, |
| // +-------------+---------------+---------+---------------------+----------------------+ |
| a_row < AllOk , error_found ,ErrorMode, &p::report_error >, |
| a_row < ErrorMode ,end_error ,AllOk , &p::report_end_error > |
| // +-------------+---------------+---------+---------------------+----------------------+ |
| > {}; |
| |
| |
| // Replaces the default no-transition response. |
| template <class FSM,class Event> |
| void no_transition(Event const& e, FSM&,int state) |
| { |
| std::cout << "no transition from state " << state |
| << " on event " << typeid(e).name() << std::endl; |
| } |
| }; |
| typedef msm::back::state_machine<player_> player; |
| |
| // |
| // Testing utilities. |
| // |
| |
| void pstate(player const& p) |
| { |
| typedef player::stt Stt; |
| typedef msm::back::generate_state_set<Stt>::type all_states; |
| static char const* state_names[mpl::size<all_states>::value]; |
| // fill the names of the states defined in the state machine |
| mpl::for_each<all_states,boost::msm::wrap<mpl::placeholders::_1> > |
| (msm::back::fill_state_names<Stt>(state_names)); |
| |
| for (unsigned int i=0;i<player::nr_regions::value;++i) |
| { |
| std::cout << " -> " << state_names[p.current_state()[i]] << std::endl; |
| } |
| } |
| |
| void test() |
| { |
| player p; |
| // needed to start the highest-level SM. This will call on_entry and mark the start of the SM |
| p.start(); |
| std::cout << "CDLoaded active:" << std::boolalpha << p.is_flag_active<CDLoaded>() << std::endl; //=> false (no CD yet) |
| |
| // test deferred event |
| // deferred in Empty and Open, will be handled only after event cd_detected |
| std::cout << "play is not handled in the current state but is marked as delayed" << std::endl; |
| p.process_event(play()); pstate(p); |
| std::cout << "cd_detected will cause play to be handled also" << std::endl; |
| // will be rejected, wrong disk type |
| p.process_event(cd_detected(DISK_DVD)); pstate(p); |
| // will be accepted, wrong disk type |
| p.process_event(cd_detected(DISK_CD)); pstate(p); |
| |
| std::cout << "FirstSong active:" << std::boolalpha << p.is_flag_active<FirstSongPlaying>() << std::endl; //=> true |
| p.process_event(NextSong());pstate(p); |
| // We are now in second song, Flag inactive |
| std::cout << "FirstSong active:" << std::boolalpha << p.is_flag_active<FirstSongPlaying>() << std::endl;//=> false |
| p.process_event(NextSong());pstate(p); |
| // 2nd song active |
| p.process_event(PreviousSong());pstate(p); |
| // Pause |
| p.process_event(pause()); pstate(p); |
| // go back to Playing |
| // but end_pause is an event activating the History |
| // => keep the last active State (SecondSong) |
| p.process_event(end_pause()); pstate(p); |
| // force an exit by listening all the songs |
| p.process_event(NextSong()); |
| p.process_event(NextSong());pstate(p); |
| |
| std::cout << "CDLoaded active:" << std::boolalpha << p.is_flag_active<CDLoaded>() << std::endl;//=> true |
| std::cout << "FirstSong active:" << std::boolalpha << p.is_flag_active<FirstSongPlaying>() << std::endl;//=> false |
| |
| // go back to Playing |
| // but play is not leading to Shallow History => do not remember the last active State (SecondSong) |
| // and activate again FirstSong and LightOn |
| p.process_event(play()); pstate(p); |
| p.process_event(error_found()); pstate(p); |
| |
| // try generating more events |
| std::cout << "Trying to generate another event" << std::endl; // will not work, fsm is terminated or interrupted |
| p.process_event(NextSong());pstate(p); |
| |
| std::cout << "Trying to end the error" << std::endl; // will work only if ErrorMode is interrupt state |
| p.process_event(end_error());pstate(p); |
| std::cout << "Trying to generate another event" << std::endl; // will work only if ErrorMode is interrupt state |
| p.process_event(NextSong());pstate(p); |
| |
| // the states and events of the higher level FSM (player) |
| typedef player::stt Stt; |
| typedef msm::back::generate_state_set<Stt>::type simple_states; |
| |
| std::cout << "the state list:" << std::endl; |
| mpl::for_each<simple_states,boost::msm::wrap<mpl::placeholders::_1> >(msm::back::display_type ()); |
| |
| std::cout << "the event list:" << std::endl; |
| typedef msm::back::generate_event_set<Stt>::type event_list; |
| mpl::for_each<event_list,boost::msm::wrap<mpl::placeholders::_1> >(msm::back::display_type ()); |
| std::cout << std::endl; |
| |
| // the states and events recursively searched |
| typedef msm::back::recursive_get_transition_table<player>::type recursive_stt; |
| |
| std::cout << "the state list (including sub-SMs):" << std::endl; |
| |
| typedef msm::back::generate_state_set<recursive_stt>::type all_states; |
| mpl::for_each<all_states,boost::msm::wrap<mpl::placeholders::_1> >(msm::back::display_type ()); |
| |
| std::cout << "the event list (including sub-SMs):" << std::endl; |
| typedef msm::back::generate_event_set<recursive_stt>::type all_events; |
| mpl::for_each<all_events,boost::msm::wrap<mpl::placeholders::_1> >(msm::back::display_type ()); |
| |
| } |
| } |
| |
| int main() |
| { |
| test(); |
| return 0; |
| } |
| |
| |