267 lines
12 KiB
C++
267 lines
12 KiB
C++
// 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 headers that implement a archive in simple text format
|
|
#include <boost/archive/text_oarchive.hpp>
|
|
#include <boost/archive/text_iarchive.hpp>
|
|
#include <boost/serialization/tracking.hpp>
|
|
|
|
#include <fstream>
|
|
|
|
namespace msm = boost::msm;
|
|
namespace mpl = boost::mpl;
|
|
|
|
namespace
|
|
{
|
|
// events
|
|
struct play {};
|
|
struct end_pause {};
|
|
struct stop {};
|
|
struct pause {};
|
|
struct open_close {};
|
|
struct NextSong {};
|
|
struct PreviousSong {};
|
|
|
|
// A "complicated" event type that carries some data.
|
|
struct cd_detected
|
|
{
|
|
cd_detected(std::string name)
|
|
: name(name)
|
|
{}
|
|
|
|
std::string name;
|
|
};
|
|
|
|
// 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;}
|
|
};
|
|
|
|
struct Stopped : public msm::front::state<>
|
|
{
|
|
// when stopped, the CD is loaded
|
|
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;}
|
|
};
|
|
|
|
struct Playing_ : public msm::front::state_machine_def<Playing_>
|
|
{
|
|
// when playing, the CD is loaded and we are in either pause or playing (duh)
|
|
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<>
|
|
{
|
|
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;}
|
|
};
|
|
// 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"; }
|
|
// guard conditions
|
|
|
|
typedef Playing_ pl; // makes transition table cleaner
|
|
// Transition table for Playing
|
|
struct transition_table : mpl::vector4<
|
|
// 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 >
|
|
// +---------+-------------+---------+---------------------+----------------------+
|
|
> {};
|
|
// 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;
|
|
}
|
|
|
|
};
|
|
// back-end
|
|
// 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
|
|
typedef msm::back::state_machine<Playing_,msm::back::ShallowHistory<mpl::vector<end_pause> > > Playing;
|
|
|
|
// state not defining any entry or exit
|
|
struct Paused : public msm::front::state<>
|
|
{
|
|
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;}
|
|
};
|
|
|
|
// 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& cd) {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
|
|
|
|
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 >,
|
|
a_row < Empty , cd_detected , Stopped , &p::store_cd_info >,
|
|
// +---------+-------------+---------+---------------------+----------------------+
|
|
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();
|
|
// 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);
|
|
p.process_event(cd_detected("louie, louie"));
|
|
p.process_event(play());
|
|
|
|
// at this point, Play is active
|
|
// make transition happen inside it. Player has no idea about this event but it's ok.
|
|
p.process_event(NextSong());pstate(p); //2nd song active
|
|
p.process_event(NextSong());pstate(p);//3rd song active
|
|
p.process_event(PreviousSong());pstate(p);//2nd song active
|
|
p.process_event(pause()); pstate(p);
|
|
std::ofstream ofs("fsm.txt");
|
|
// save fsm to archive (current state is Pause, Playing is in Song2)
|
|
{
|
|
boost::archive::text_oarchive oa(ofs);
|
|
// write class instance to archive
|
|
oa << p;
|
|
}
|
|
// reload fsm in state Open
|
|
player p2;
|
|
{
|
|
// create and open an archive for input
|
|
std::ifstream ifs("fsm.txt");
|
|
boost::archive::text_iarchive ia(ifs);
|
|
// read class state from archive
|
|
ia >> p2;
|
|
}
|
|
// go back to Playing
|
|
// as you see, remembers the original state as end_pause is an history trigger
|
|
p2.process_event(end_pause()); pstate(p2);
|
|
p2.process_event(pause()); pstate(p2);
|
|
p2.process_event(stop()); pstate(p2);
|
|
// event leading to the same state
|
|
p2.process_event(stop()); pstate(p2);
|
|
// play does not trigger shallow history => start back from 1st song
|
|
p2.process_event(play()); pstate(p2);
|
|
}
|
|
}
|
|
// eliminate object tracking (even if serialized through a pointer)
|
|
// at the risk of a programming error creating duplicate objects.
|
|
// this is to get rid of warning because p is not const
|
|
BOOST_CLASS_TRACKING(player, boost::serialization::track_never)
|
|
|
|
int main()
|
|
{
|
|
test();
|
|
return 0;
|
|
}
|