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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 | ||
17 | namespace msm = boost::msm; | |
18 | namespace mpl = boost::mpl; | |
19 | ||
20 | struct SomeExternalContext | |
21 | { | |
22 | SomeExternalContext(int b):bla(b){} | |
23 | int bla; | |
24 | }; | |
25 | ||
26 | namespace | |
27 | { | |
28 | // events | |
29 | struct play {}; | |
30 | struct end_pause {}; | |
31 | struct stop {}; | |
32 | struct pause {}; | |
33 | struct open_close {}; | |
34 | struct NextSong {}; | |
35 | struct PreviousSong {}; | |
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 | player_(SomeExternalContext& context,int someint) | |
58 | :context_(context) | |
59 | { | |
60 | std::cout << "context value:" << context_.bla << " with value:" << someint << std::endl; | |
61 | context.bla = 10; | |
62 | } | |
63 | ||
64 | SomeExternalContext& context_; | |
65 | ||
66 | // The list of FSM states | |
67 | struct Empty : public msm::front::state<> | |
68 | { | |
69 | int data_; | |
70 | Empty():data_(0){} | |
71 | Empty(int i):data_(i){} | |
72 | // every (optional) entry/exit methods get the event passed. | |
73 | template <class Event,class FSM> | |
74 | void on_entry(Event const&,FSM& ) {std::cout << "entering: Empty" << std::endl;} | |
75 | template <class Event,class FSM> | |
76 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Empty" << std::endl;} | |
77 | }; | |
78 | struct Open : public msm::front::state<> | |
79 | { | |
80 | int data_; | |
81 | Open():data_(0){} | |
82 | Open(int i):data_(i){} | |
83 | ||
84 | template <class Event,class FSM> | |
85 | void on_entry(Event const& ,FSM&) {std::cout << "entering: Open" << std::endl;} | |
86 | template <class Event,class FSM> | |
87 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Open" << std::endl;} | |
88 | }; | |
89 | ||
90 | // sm_ptr still supported but deprecated as functors are a much better way to do the same thing | |
91 | struct Stopped : public msm::front::state<msm::front::default_base_state,msm::front::sm_ptr> | |
92 | { | |
93 | template <class Event,class FSM> | |
94 | void on_entry(Event const& ,FSM&) {std::cout << "entering: Stopped" << std::endl;} | |
95 | template <class Event,class FSM> | |
96 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Stopped" << std::endl;} | |
97 | void set_sm_ptr(player_* pl) | |
98 | { | |
99 | m_player=pl; | |
100 | } | |
101 | player_* m_player; | |
102 | }; | |
103 | ||
104 | struct Playing_ : public msm::front::state_machine_def<Playing_> | |
105 | { | |
106 | // when playing, the CD is loaded and we are in either pause or playing (duh) | |
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 | // The list of FSM states | |
113 | struct Song1 : public msm::front::state<> | |
114 | { | |
115 | int data_; | |
116 | Song1():data_(0){} | |
117 | Song1(int i):data_(i){} | |
118 | ||
119 | template <class Event,class FSM> | |
120 | void on_entry(Event const&,FSM& ) {std::cout << "starting: First song" << std::endl;} | |
121 | template <class Event,class FSM> | |
122 | void on_exit(Event const&,FSM& ) {std::cout << "finishing: First Song" << std::endl;} | |
123 | ||
124 | }; | |
125 | struct Song2 : public msm::front::state<> | |
126 | { | |
127 | template <class Event,class FSM> | |
128 | void on_entry(Event const&,FSM& ) {std::cout << "starting: Second song" << std::endl;} | |
129 | template <class Event,class FSM> | |
130 | void on_exit(Event const&,FSM& ) {std::cout << "finishing: Second Song" << std::endl;} | |
131 | }; | |
132 | struct Song3 : public msm::front::state<> | |
133 | { | |
134 | template <class Event,class FSM> | |
135 | void on_entry(Event const&,FSM& ) {std::cout << "starting: Third song" << std::endl;} | |
136 | template <class Event,class FSM> | |
137 | void on_exit(Event const&,FSM& ) {std::cout << "finishing: Third Song" << std::endl;} | |
138 | }; | |
139 | // the initial state. Must be defined | |
140 | typedef Song1 initial_state; | |
141 | // transition actions | |
142 | void start_next_song(NextSong const&) { std::cout << "Playing::start_next_song\n"; } | |
143 | void start_prev_song(PreviousSong const&) { std::cout << "Playing::start_prev_song\n"; } | |
144 | // guard conditions | |
145 | ||
146 | typedef Playing_ pl; // makes transition table cleaner | |
147 | // Transition table for Playing | |
148 | struct transition_table : mpl::vector4< | |
149 | // Start Event Next Action Guard | |
150 | // +---------+-------------+---------+---------------------+----------------------+ | |
151 | a_row < Song1 , NextSong , Song2 , &pl::start_next_song >, | |
152 | a_row < Song2 , PreviousSong, Song1 , &pl::start_prev_song >, | |
153 | a_row < Song2 , NextSong , Song3 , &pl::start_next_song >, | |
154 | a_row < Song3 , PreviousSong, Song2 , &pl::start_prev_song > | |
155 | // +---------+-------------+---------+---------------------+----------------------+ | |
156 | > {}; | |
157 | // Replaces the default no-transition response. | |
158 | template <class FSM,class Event> | |
159 | void no_transition(Event const& e, FSM&,int state) | |
160 | { | |
161 | std::cout << "no transition from state " << state | |
162 | << " on event " << typeid(e).name() << std::endl; | |
163 | } | |
164 | }; | |
165 | // back-end | |
166 | typedef msm::back::state_machine<Playing_> Playing; | |
167 | ||
168 | // state not defining any entry or exit | |
169 | struct Paused : public msm::front::state<> | |
170 | { | |
171 | }; | |
172 | ||
173 | // the initial state of the player SM. Must be defined | |
174 | typedef Empty initial_state; | |
175 | ||
176 | // transition actions | |
177 | void start_playback(play const&) { std::cout << "player::start_playback\n"; } | |
178 | void open_drawer(open_close const&) { std::cout << "player::open_drawer\n"; } | |
179 | void close_drawer(open_close const&) { std::cout << "player::close_drawer\n"; } | |
180 | void store_cd_info(cd_detected const&) { std::cout << "player::store_cd_info\n"; } | |
181 | void stop_playback(stop const&) { std::cout << "player::stop_playback\n"; } | |
182 | void pause_playback(pause const&) { std::cout << "player::pause_playback\n"; } | |
183 | void resume_playback(end_pause const&) { std::cout << "player::resume_playback\n"; } | |
184 | void stop_and_open(open_close const&) { std::cout << "player::stop_and_open\n"; } | |
185 | void stopped_again(stop const&) {std::cout << "player::stopped_again\n";} | |
186 | // guard conditions | |
187 | bool good_disk_format(cd_detected const& evt) | |
188 | { | |
189 | // to test a guard condition, let's say we understand only CDs, not DVD | |
190 | if (evt.disc_type != DISK_CD) | |
191 | { | |
192 | std::cout << "wrong disk, sorry" << std::endl; | |
193 | return false; | |
194 | } | |
195 | return true; | |
196 | } | |
197 | // used to show a transition conflict. This guard will simply deactivate one transition and thus | |
198 | // solve the conflict | |
199 | bool auto_start(cd_detected const&) | |
200 | { | |
201 | return false; | |
202 | } | |
203 | ||
204 | typedef player_ p; // makes transition table cleaner | |
205 | ||
206 | // Transition table for player | |
207 | struct transition_table : mpl::vector< | |
208 | // Start Event Next Action Guard | |
209 | // +---------+-------------+---------+---------------------+----------------------+ | |
210 | a_row < Stopped , play , Playing , &p::start_playback >, | |
211 | a_row < Stopped , open_close , Open , &p::open_drawer >, | |
212 | _row < Stopped , stop , Stopped >, | |
213 | // +---------+-------------+---------+---------------------+----------------------+ | |
214 | a_row < Open , open_close , Empty , &p::close_drawer >, | |
215 | // +---------+-------------+---------+---------------------+----------------------+ | |
216 | a_row < Empty , open_close , Open , &p::open_drawer >, | |
217 | row < Empty , cd_detected , Stopped , &p::store_cd_info ,&p::good_disk_format >, | |
218 | row < Empty , cd_detected , Playing , &p::store_cd_info ,&p::auto_start >, | |
219 | // +---------+-------------+---------+---------------------+----------------------+ | |
220 | a_row < Playing , stop , Stopped , &p::stop_playback >, | |
221 | a_row < Playing , pause , Paused , &p::pause_playback >, | |
222 | a_row < Playing , open_close , Open , &p::stop_and_open >, | |
223 | // +---------+-------------+---------+---------------------+----------------------+ | |
224 | a_row < Paused , end_pause , Playing , &p::resume_playback >, | |
225 | a_row < Paused , stop , Stopped , &p::stop_playback >, | |
226 | a_row < Paused , open_close , Open , &p::stop_and_open > | |
227 | // +---------+-------------+---------+---------------------+----------------------+ | |
228 | > {}; | |
229 | // Replaces the default no-transition response. | |
230 | template <class FSM,class Event> | |
231 | void no_transition(Event const& e, FSM&,int state) | |
232 | { | |
233 | std::cout << "no transition from state " << state | |
234 | << " on event " << typeid(e).name() << std::endl; | |
235 | } | |
236 | }; | |
237 | // Pick a back-end | |
238 | typedef msm::back::state_machine<player_> player; | |
239 | ||
240 | // | |
241 | // Testing utilities. | |
242 | // | |
243 | static char const* const state_names[] = { "Stopped", "Open", "Empty", "Playing", "Paused" }; | |
244 | void pstate(player const& p) | |
245 | { | |
246 | std::cout << " -> " << state_names[p.current_state()[0]] << std::endl; | |
247 | } | |
248 | ||
249 | void test() | |
250 | { | |
251 | SomeExternalContext ctx(3); | |
252 | // example 1 | |
253 | // create a player with an argument by reference and an int | |
254 | // (go to the constructor front-end) | |
255 | player p1(boost::ref(ctx),5); | |
256 | ||
257 | // example 2 | |
258 | // create a player with a copy of an Empty state, an argument by reference and an int | |
259 | // (last 2 go to the constructor front-end) | |
260 | player p2(msm::back::states_ << player_::Empty(1),boost::ref(ctx),5); | |
261 | std::cout << "Empty's data should be 1. Is: " << p2.get_state<player_::Empty&>().data_ << std::endl; | |
262 | ||
263 | std::cout << "Set a new Empty state" << std::endl; | |
264 | p2.set_states(msm::back::states_ << player_::Empty(5)); | |
265 | std::cout << "Empty's data should be 5. Is: " << p2.get_state<player_::Empty&>().data_ << std::endl; | |
266 | ||
267 | std::cout << "Set new Empty and Open states" << std::endl; | |
268 | p2.set_states(msm::back::states_ << player_::Empty(7) << player_::Open(2)); | |
269 | std::cout << "Empty's data should be 7. Is: " << p2.get_state<player_::Empty&>().data_ << std::endl; | |
270 | std::cout << "Open's data should be 2. Is: " << p2.get_state<player_::Open&>().data_ << std::endl; | |
271 | ||
272 | // example 3 | |
273 | // create a player with a copy of an Empty state, a copy of a Playing submachine | |
274 | // (which is itself created by a copy of Song1) | |
275 | // an argument by reference and an int | |
276 | // (last 2 go to the constructor front-end) | |
277 | player p(msm::back::states_ << player_::Empty(1) | |
278 | << player_::Playing(msm::back::states_ << player_::Playing_::Song1(8)), | |
279 | boost::ref(ctx),5); | |
280 | ||
281 | std::cout << "Song1's data should be 8. Is: " | |
282 | << p.get_state<player_::Playing&>().get_state<player_::Playing_::Song1&>().data_ << std::endl; | |
283 | ||
284 | ||
285 | } | |
286 | } | |
287 | ||
288 | int main() | |
289 | { | |
290 | test(); | |
291 | return 0; | |
292 | } |