ceph/src/boost/libs/mpl/example/fsm/player.cpp

   1
   2 // Copyright Aleksey Gurtovoy 2002-2004
   3 //
   4 // Distributed under the Boost Software License, Version 1.0.
   5 // (See accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt)
   7 //
   8 // See http://www.boost.org/libs/mpl for documentation.
   9
  10 // $Id$
  11 // $Date$
  12 // $Revision$
  13
  14 #include "state_machine.hpp"
  15 #include <boost/mpl/list.hpp>
  16
  17 #include <iostream>
  18
  19 namespace mpl = boost::mpl;
  20
  21 class player
  22     : public fsm::state_machine<player>
  23 {
  24  public:
  25     player() {}
  26
  27     // events
  28     struct play_event : event<play_event> {};
  29     struct stop_event : event<stop_event> {};
  30     struct pause_event : event<pause_event> {};
  31
  32 // MWCW 8.1 is too eager in inforcing access for non-type template parameters
  33 // private:
  34     typedef player self_t;
  35
  36     // state invariants
  37     void stopped_state_invariant() const {}
  38     void playing_state_invariant() const {}
  39     void paused_state_invariant() const {}
  40
  41     // states (invariants are passed as non-type template arguments)
  42     typedef state<0, &self_t::stopped_state_invariant> stopped;
  43     typedef state<1, &self_t::playing_state_invariant> playing;
  44     typedef state<2, &self_t::paused_state_invariant> paused;
  45
  46 // private:
  47
  48     // transition functions
  49     bool do_play(play_event const&) { std::cout << "player::do_play\n"; return true; }
  50     bool do_stop(stop_event const&) { std::cout << "player::do_stop\n"; return true; }
  51     bool do_pause(pause_event const&) { std::cout << "player::do_pause\n"; return true; }
  52     bool do_resume(play_event const&) { std::cout << "player::do_resume\n"; return true; }
  53
  54     // transitions, in the following format:
  55     // | current state | event | next state | transition function |
  56     friend class fsm::state_machine<player>;
  57     typedef mpl::list<
  58           transition<stopped, play_event,  playing, &player::do_play>
  59         , transition<playing, stop_event,  stopped, &player::do_stop>
  60         , transition<playing, pause_event, paused,  &player::do_pause>
  61         , transition<paused,  play_event,  playing, &player::do_resume>
  62         , transition<paused,  stop_event,  stopped, &player::do_stop>
  63         >::type transition_table;
  64
  65     typedef stopped initial_state;
  66 };
  67
  68 int main()
  69 {
  70     player p;
  71     p.process_event(player::play_event());
  72     p.process_event(player::pause_event());
  73     p.process_event(player::play_event());
  74     p.process_event(player::stop_event());
  75     return 0;
  76 }