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1 | // Copyright 2010 Christophe Henry |
2 | // henry UNDERSCORE christophe AT hotmail DOT com | |
3 | // This is an extended version of the state machine available in the boost::mpl library | |
4 | // Distributed under the same license as the original. | |
5 | // Copyright for the original version: | |
6 | // Copyright 2005 David Abrahams and Aleksey Gurtovoy. Distributed | |
7 | // under the Boost Software License, Version 1.0. (See accompanying | |
8 | // file LICENSE_1_0.txt or copy at | |
9 | // http://www.boost.org/LICENSE_1_0.txt) | |
10 | ||
11 | #include <iostream> | |
12 | // back-end | |
13 | #include <boost/msm/back/state_machine.hpp> | |
14 | //front-end | |
15 | #include <boost/msm/front/state_machine_def.hpp> | |
16 | #include <boost/msm/front/functor_row.hpp> | |
17 | #include <boost/msm/front/euml/common.hpp> | |
18 | // for And_ operator | |
19 | #include <boost/msm/front/euml/operator.hpp> | |
20 | ||
21 | using namespace std; | |
22 | namespace msm = boost::msm; | |
23 | using namespace msm::front; | |
24 | namespace mpl = boost::mpl; | |
25 | // for And_ operator | |
26 | using namespace msm::front::euml; | |
27 | ||
28 | namespace | |
29 | { | |
30 | // events | |
31 | struct play {}; | |
32 | struct end_pause {}; | |
33 | struct stop {}; | |
34 | struct pause {}; | |
35 | struct open_close {}; | |
36 | ||
37 | // A "complicated" event type that carries some data. | |
38 | enum DiskTypeEnum | |
39 | { | |
40 | DISK_CD=0, | |
41 | DISK_DVD=1 | |
42 | }; | |
43 | struct cd_detected | |
44 | { | |
45 | cd_detected(std::string name, DiskTypeEnum diskType) | |
46 | : name(name), | |
47 | disc_type(diskType) | |
48 | {} | |
49 | ||
50 | std::string name; | |
51 | DiskTypeEnum disc_type; | |
52 | }; | |
53 | ||
54 | // front-end: define the FSM structure | |
55 | struct player_ : public msm::front::state_machine_def<player_> | |
56 | { | |
57 | // The list of FSM states | |
58 | struct Empty : public msm::front::state<> | |
59 | { | |
60 | // every (optional) entry/exit methods get the event passed. | |
61 | template <class Event,class FSM> | |
62 | void on_entry(Event const&,FSM& ) {std::cout << "entering: Empty" << std::endl;} | |
63 | template <class Event,class FSM> | |
64 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Empty" << std::endl;} | |
65 | struct internal_guard_fct | |
66 | { | |
67 | template <class EVT,class FSM,class SourceState,class TargetState> | |
68 | bool operator()(EVT const& evt ,FSM&,SourceState& ,TargetState& ) | |
69 | { | |
70 | std::cout << "Empty::internal_transition_table guard\n"; | |
71 | return false; | |
72 | } | |
73 | }; | |
74 | struct internal_action_fct | |
75 | { | |
76 | template <class EVT,class FSM,class SourceState,class TargetState> | |
77 | void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) | |
78 | { | |
79 | std::cout << "Empty::internal_transition_table action" << std::endl; | |
80 | } | |
81 | }; | |
82 | // Transition table for Empty | |
83 | struct internal_transition_table : mpl::vector< | |
84 | // Start Event Next Action Guard | |
85 | Internal < cd_detected , internal_action_fct ,internal_guard_fct > | |
86 | // +---------+-------------+---------+---------------------+----------------------+ | |
87 | > {}; | |
88 | }; | |
89 | struct Open : public msm::front::state<> | |
90 | { | |
91 | template <class Event,class FSM> | |
92 | void on_entry(Event const& ,FSM&) {std::cout << "entering: Open" << std::endl;} | |
93 | template <class Event,class FSM> | |
94 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Open" << std::endl;} | |
95 | }; | |
96 | ||
97 | struct Stopped : public msm::front::state<> | |
98 | { | |
99 | template <class Event,class FSM> | |
100 | void on_entry(Event const& ,FSM&) {std::cout << "entering: Stopped" << std::endl;} | |
101 | template <class Event,class FSM> | |
102 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Stopped" << std::endl;} | |
103 | }; | |
104 | ||
105 | struct Playing : public msm::front::state<> | |
106 | { | |
107 | template <class Event,class FSM> | |
108 | void on_entry(Event const&,FSM& ) {std::cout << "entering: Playing" << std::endl;} | |
109 | template <class Event,class FSM> | |
110 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Playing" << std::endl;} | |
111 | }; | |
112 | ||
113 | // state not defining any entry or exit | |
114 | struct Paused : public msm::front::state<> | |
115 | { | |
116 | }; | |
117 | ||
118 | // the initial state of the player SM. Must be defined | |
119 | typedef Empty initial_state; | |
120 | ||
121 | // transition actions | |
122 | // as the functors are generic on events, fsm and source/target state, | |
123 | // you can reuse them in another machine if you wish | |
124 | struct TestFct | |
125 | { | |
126 | template <class EVT,class FSM,class SourceState,class TargetState> | |
127 | void operator()(EVT const&, FSM&,SourceState& ,TargetState& ) | |
128 | { | |
129 | cout << "transition with event:" << typeid(EVT).name() << endl; | |
130 | } | |
131 | }; | |
132 | struct start_playback | |
133 | { | |
134 | template <class EVT,class FSM,class SourceState,class TargetState> | |
135 | void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) | |
136 | { | |
137 | cout << "player::start_playback" << endl; | |
138 | } | |
139 | }; | |
140 | struct open_drawer | |
141 | { | |
142 | template <class EVT,class FSM,class SourceState,class TargetState> | |
143 | void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) | |
144 | { | |
145 | cout << "player::open_drawer" << endl; | |
146 | } | |
147 | }; | |
148 | struct close_drawer | |
149 | { | |
150 | template <class EVT,class FSM,class SourceState,class TargetState> | |
151 | void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) | |
152 | { | |
153 | cout << "player::close_drawer" << endl; | |
154 | } | |
155 | }; | |
156 | struct store_cd_info | |
157 | { | |
158 | template <class EVT,class FSM,class SourceState,class TargetState> | |
159 | void operator()(EVT const&,FSM& fsm ,SourceState& ,TargetState& ) | |
160 | { | |
161 | cout << "player::store_cd_info" << endl; | |
162 | fsm.process_event(play()); | |
163 | } | |
164 | }; | |
165 | struct stop_playback | |
166 | { | |
167 | template <class EVT,class FSM,class SourceState,class TargetState> | |
168 | void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) | |
169 | { | |
170 | cout << "player::stop_playback" << endl; | |
171 | } | |
172 | }; | |
173 | struct pause_playback | |
174 | { | |
175 | template <class EVT,class FSM,class SourceState,class TargetState> | |
176 | void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) | |
177 | { | |
178 | cout << "player::pause_playback" << endl; | |
179 | } | |
180 | }; | |
181 | struct resume_playback | |
182 | { | |
183 | template <class EVT,class FSM,class SourceState,class TargetState> | |
184 | void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) | |
185 | { | |
186 | cout << "player::resume_playback" << endl; | |
187 | } | |
188 | }; | |
189 | struct stop_and_open | |
190 | { | |
191 | template <class EVT,class FSM,class SourceState,class TargetState> | |
192 | void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) | |
193 | { | |
194 | cout << "player::stop_and_open" << endl; | |
195 | } | |
196 | }; | |
197 | struct stopped_again | |
198 | { | |
199 | template <class EVT,class FSM,class SourceState,class TargetState> | |
200 | void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) | |
201 | { | |
202 | cout << "player::stopped_again" << endl; | |
203 | } | |
204 | }; | |
205 | // guard conditions | |
206 | struct DummyGuard | |
207 | { | |
208 | template <class EVT,class FSM,class SourceState,class TargetState> | |
209 | bool operator()(EVT const& evt,FSM& fsm,SourceState& src,TargetState& tgt) | |
210 | { | |
211 | return true; | |
212 | } | |
213 | }; | |
214 | struct good_disk_format | |
215 | { | |
216 | template <class EVT,class FSM,class SourceState,class TargetState> | |
217 | bool operator()(EVT const& evt ,FSM&,SourceState& ,TargetState& ) | |
218 | { | |
219 | // to test a guard condition, let's say we understand only CDs, not DVD | |
220 | if (evt.disc_type != DISK_CD) | |
221 | { | |
222 | std::cout << "wrong disk, sorry" << std::endl; | |
223 | return false; | |
224 | } | |
225 | return true; | |
226 | } | |
227 | }; | |
228 | struct always_true | |
229 | { | |
230 | template <class EVT,class FSM,class SourceState,class TargetState> | |
231 | bool operator()(EVT const& evt ,FSM&,SourceState& ,TargetState& ) | |
232 | { | |
233 | return true; | |
234 | } | |
235 | }; | |
236 | struct internal_guard | |
237 | { | |
238 | template <class EVT,class FSM,class SourceState,class TargetState> | |
239 | bool operator()(EVT const& evt ,FSM&,SourceState& ,TargetState& ) | |
240 | { | |
241 | std::cout << "Empty::internal guard\n"; | |
242 | return false; | |
243 | } | |
244 | }; | |
245 | // Transition table for player | |
246 | struct transition_table : mpl::vector< | |
247 | // Start Event Next Action Guard | |
248 | // +---------+-------------+---------+---------------------------+----------------------+ | |
249 | Row < Stopped , play , Playing , ActionSequence_ | |
250 | <mpl::vector< | |
251 | TestFct,start_playback> > | |
252 | , DummyGuard >, | |
253 | Row < Stopped , open_close , Open , open_drawer , none >, | |
254 | Row < Stopped , stop , Stopped , none , none >, | |
255 | // +---------+-------------+---------+---------------------------+----------------------+ | |
256 | Row < Open , open_close , Empty , close_drawer , none >, | |
257 | // +---------+-------------+---------+---------------------------+----------------------+ | |
258 | Row < Empty , open_close , Open , open_drawer , none >, | |
259 | Row < Empty , cd_detected , Stopped , store_cd_info , And_<good_disk_format, | |
260 | always_true> >, | |
261 | // internal transition inside the stt: none as Target | |
262 | Row < Empty , cd_detected , none , none , internal_guard >, | |
263 | // +---------+-------------+---------+---------------------------+----------------------+ | |
264 | Row < Playing , stop , Stopped , stop_playback , none >, | |
265 | Row < Playing , pause , Paused , pause_playback , none >, | |
266 | Row < Playing , open_close , Open , stop_and_open , none >, | |
267 | // +---------+-------------+---------+---------------------------+----------------------+ | |
268 | Row < Paused , end_pause , Playing , resume_playback , none >, | |
269 | Row < Paused , stop , Stopped , stop_playback , none >, | |
270 | Row < Paused , open_close , Open , stop_and_open , none > | |
271 | // +---------+-------------+---------+---------------------------+----------------------+ | |
272 | > {}; | |
273 | // Replaces the default no-transition response. | |
274 | template <class FSM,class Event> | |
275 | void no_transition(Event const& e, FSM&,int state) | |
276 | { | |
277 | std::cout << "no transition from state " << state | |
278 | << " on event " << typeid(e).name() << std::endl; | |
279 | } | |
280 | }; | |
281 | // Pick a back-end | |
282 | typedef msm::back::state_machine<player_> player; | |
283 | ||
284 | // | |
285 | // Testing utilities. | |
286 | // | |
287 | static char const* const state_names[] = { "Stopped", "Open", "Empty", "Playing", "Paused" }; | |
288 | void pstate(player const& p) | |
289 | { | |
290 | std::cout << " -> " << state_names[p.current_state()[0]] << std::endl; | |
291 | } | |
292 | ||
293 | void test() | |
294 | { | |
295 | player p; | |
296 | // needed to start the highest-level SM. This will call on_entry and mark the start of the SM | |
297 | p.start(); | |
298 | // go to Open, call on_exit on Empty, then action, then on_entry on Open | |
299 | p.process_event(open_close()); pstate(p); | |
300 | p.process_event(open_close()); pstate(p); | |
301 | // will be rejected, wrong disk type | |
302 | p.process_event( | |
303 | cd_detected("louie, louie",DISK_DVD)); pstate(p); | |
304 | p.process_event( | |
305 | cd_detected("louie, louie",DISK_CD)); pstate(p); | |
306 | // no need to call play() as the previous transition does it in its action method | |
307 | //p.process_event(play()); | |
308 | ||
309 | // at this point, Play is active | |
310 | p.process_event(pause()); pstate(p); | |
311 | // go back to Playing | |
312 | p.process_event(end_pause()); pstate(p); | |
313 | p.process_event(pause()); pstate(p); | |
314 | p.process_event(stop()); pstate(p); | |
315 | // event leading to the same state | |
316 | // no action method called as it is not present in the transition table | |
317 | p.process_event(stop()); pstate(p); | |
318 | } | |
319 | } | |
320 | ||
321 | int main() | |
322 | { | |
323 | test(); | |
324 | return 0; | |
325 | } |