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- // 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;
- }
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