| // 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 <iostream> |
| // back-end |
| #include <boost/msm/back/state_machine.hpp> |
| //front-end |
| #include <boost/msm/front/state_machine_def.hpp> |
| #include <boost/msm/front/functor_row.hpp> |
| |
| namespace msm = boost::msm; |
| namespace mpl = boost::mpl; |
| using namespace msm::front; |
| |
| namespace |
| { |
| // events |
| struct play {}; |
| struct end_pause {}; |
| struct stop {}; |
| struct pause {}; |
| struct open_close {}; |
| struct to_ignore {}; |
| |
| // A "complicated" event type that carries some data. |
| enum DiskTypeEnum |
| { |
| DISK_CD=0, |
| DISK_DVD=1 |
| }; |
| struct cd_detected |
| { |
| cd_detected(std::string name, DiskTypeEnum diskType) |
| : name(name), |
| disc_type(diskType) |
| {} |
| |
| std::string name; |
| DiskTypeEnum disc_type; |
| }; |
| |
| // front-end: define the FSM structure |
| struct player_ : public msm::front::state_machine_def<player_> |
| { |
| // The list of FSM states |
| struct Empty : public msm::front::state<> |
| { |
| // every (optional) entry/exit methods get the event passed. |
| 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<> |
| { |
| 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;} |
| }; |
| |
| // sm_ptr still supported but deprecated as functors are a much better way to do the same thing |
| struct Stopped : public msm::front::state<msm::front::default_base_state,msm::front::sm_ptr> |
| { |
| 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; |
| }; |
| |
| struct Playing : public msm::front::state<> |
| { |
| 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;} |
| }; |
| |
| // state not defining any entry or exit |
| struct Paused : public msm::front::state<> |
| { |
| }; |
| |
| // the initial state of the player SM. Must be defined |
| typedef Empty 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"; } |
| void stop_playback(stop const&) { std::cout << "player::stop_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";} |
| // 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; |
| } |
| // transitions internal to Empty |
| void internal_action(cd_detected const&){ std::cout << "Empty::internal action\n"; } |
| bool internal_guard(cd_detected const&) |
| { |
| std::cout << "Empty::internal guard\n"; |
| return false; |
| } |
| struct internal_guard_fct |
| { |
| template <class EVT,class FSM,class SourceState,class TargetState> |
| bool operator()(EVT const& evt ,FSM&,SourceState& ,TargetState& ) |
| { |
| std::cout << "Empty::internal guard functor\n"; |
| return false; |
| } |
| }; |
| struct internal_action_fct |
| { |
| template <class EVT,class FSM,class SourceState,class TargetState> |
| void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) |
| { |
| std::cout << "Empty::internal action functor" << std::endl; |
| } |
| }; |
| |
| 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 >, |
| _row < Stopped , stop , Stopped >, |
| // +---------+-------------+---------+---------------------+----------------------+ |
| 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 >, |
| irow < Empty , cd_detected , &p::internal_action ,&p::internal_guard >, |
| _irow < Empty , to_ignore >, |
| g_irow < Empty , cd_detected ,&p::internal_guard >, |
| Row < Empty , cd_detected , none , internal_action_fct ,internal_guard_fct >, |
| // +---------+-------------+---------+---------------------+----------------------+ |
| 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 < 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 > |
| // +---------+-------------+---------+---------------------+----------------------+ |
| > {}; |
| // 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; |
| } |
| }; |
| // Pick a back-end |
| typedef msm::back::state_machine<player_> player; |
| |
| // |
| // Testing utilities. |
| // |
| static char const* const state_names[] = { "Stopped", "Open", "Empty", "Playing", "Paused" }; |
| void pstate(player const& p) |
| { |
| std::cout << " -> " << state_names[p.current_state()[0]] << 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(); |
| // this event will be ignored and not call no_transition |
| p.process_event(to_ignore()); |
| // go to Open, call on_exit on Empty, then action, then on_entry on Open |
| p.process_event(open_close()); pstate(p); |
| p.process_event(open_close()); pstate(p); |
| // will be rejected, wrong disk type |
| p.process_event( |
| cd_detected("louie, louie",DISK_DVD)); pstate(p); |
| p.process_event( |
| cd_detected("louie, louie",DISK_CD)); pstate(p); |
| p.process_event(play()); |
| |
| // at this point, Play is active |
| p.process_event(pause()); pstate(p); |
| // go back to Playing |
| p.process_event(end_pause()); pstate(p); |
| p.process_event(pause()); pstate(p); |
| p.process_event(stop()); pstate(p); |
| // event leading to the same state |
| // no action method called as it is not present in the transition table |
| p.process_event(stop()); pstate(p); |
| } |
| } |
| |
| int main() |
| { |
| test(); |
| return 0; |
| } |