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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/msm/back/state_machine.hpp>
#include <boost/msm/front/euml/euml.hpp>
using namespace std;
using namespace boost::msm::front::euml;
namespace msm = boost::msm;
// entry/exit/action/guard logging functors
#include "logging_functors.h"
namespace // Concrete FSM implementation
{
// events
BOOST_MSM_EUML_EVENT(play)
BOOST_MSM_EUML_EVENT(end_pause)
BOOST_MSM_EUML_EVENT(stop)
BOOST_MSM_EUML_EVENT(pause)
BOOST_MSM_EUML_EVENT(open_close)
// A "complicated" event type that carries some data.
BOOST_MSM_EUML_DECLARE_ATTRIBUTE(std::string,cd_name)
BOOST_MSM_EUML_DECLARE_ATTRIBUTE(DiskTypeEnum,cd_type)
BOOST_MSM_EUML_ATTRIBUTES((attributes_ << cd_name << cd_type ), cd_detected_attributes)
BOOST_MSM_EUML_EVENT_WITH_ATTRIBUTES(cd_detected,cd_detected_attributes)
// Concrete FSM implementation
// The list of FSM states
// state not needing any entry or exit
BOOST_MSM_EUML_STATE((),Paused)
// it is also possible to define a state which you can implement normally
// just make it a state, as usual, and also a grammar terminal, euml_state
struct Empty_impl : public msm::front::state<> , public euml_state<Empty_impl>
{
// this allows us to add some functions
void activate_empty() {std::cout << "switching to Empty " << std::endl;}
// standard entry behavior
template <class Event,class FSM>
void on_entry(Event const& evt,FSM& fsm)
{
std::cout << "entering: Empty" << std::endl;
}
template <class Event,class FSM>
void on_exit(Event const& evt,FSM& fsm)
{
std::cout << "leaving: Empty" << std::endl;
}
};
//instance for use in the transition table
Empty_impl const Empty;
// create a functor and a eUML function for the activate_empty method from Entry
BOOST_MSM_EUML_METHOD(ActivateEmpty_ , activate_empty , activate_empty_ , void , void )
// define more states
BOOST_MSM_EUML_STATE(( Open_Entry,Open_Exit ),Open)
BOOST_MSM_EUML_STATE(( Stopped_Entry,Stopped_Exit ),Stopped)
BOOST_MSM_EUML_STATE(( Playing_Entry,Playing_Exit ),Playing)
// guard conditions
BOOST_MSM_EUML_ACTION(good_disk_format)
{
template <class FSM,class EVT,class SourceState,class TargetState>
bool operator()(EVT const& evt,FSM&,SourceState& ,TargetState& )
{
// to test a guard condition, let's say we understand only CDs, not DVD
if (evt.get_attribute(cd_type)!=DISK_CD)
{
std::cout << "wrong disk, sorry" << std::endl;
// just for logging, does not block any transition
return true;
}
std::cout << "good disk" << std::endl;
return true;
}
};
// it is also possible to use a plain functor, with default-constructor in the transition table
struct start_play
{
template <class FSM,class EVT,class SourceState,class TargetState>
void operator()(EVT const& ,FSM&,SourceState& ,TargetState& )
{
cout << "player::start_play" << endl;
}
};
// replaces the old transition table
BOOST_MSM_EUML_TRANSITION_TABLE((
Playing == Stopped + play / start_play() ,
Playing == Paused + end_pause / resume_playback,
// +------------------------------------------------------------------------------+
Empty == Open + open_close / (close_drawer,activate_empty_(target_)),
// +------------------------------------------------------------------------------+
Open == Empty + open_close / open_drawer,
Open == Paused + open_close / stop_and_open,
Open == Stopped + open_close / open_drawer,
Open == Playing + open_close / stop_and_open,
// +------------------------------------------------------------------------------+
Paused == Playing + pause / pause_playback,
// +------------------------------------------------------------------------------+
Stopped == Playing + stop / stop_playback,
Stopped == Paused + stop / stop_playback,
Stopped == Empty + cd_detected [good_disk_format &&
(event_(cd_type)==Int_<DISK_CD>())]
/ (store_cd_info,process_(play)),
Stopped == Stopped + stop
// +------------------------------------------------------------------------------+
),transition_table)
// create a state machine "on the fly"
BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT
init_ << Empty, // Init State
no_action, // Entry
no_action, // Exit
attributes_ << no_attributes_, // Attributes
configure_ << no_configure_, // configuration
Log_No_Transition // no_transition handler
),
player_) //fsm name
// or simply, if no no_transition handler needed:
//BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT
// Empty // Init State
// ),player_)
// choice of back-end
typedef msm::back::state_machine<player_> player;
//
// Testing utilities.
//
static char const* const state_names[] = { "Stopped", "Paused", "Open", "Empty", "Playing" };
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();
// note that we write open_close and not open_close(), like usual. Both are possible with eUML, but
// you now have less to type.
// 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);
// no need to call play as the previous event does it in its action method
//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 none is defined in the transition table
p.process_event(stop); pstate(p);
// test call to no_transition
p.process_event(pause); pstate(p);
}
}
int main()
{
test();
return 0;
}
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