statechart/example/PingPong/PingPong.cpp

//////////////////////////////////////////////////////////////////////////////
// Copyright (c) Andreas Huber Doenni 2002-2004.
// Use, modification and distribution are subject to 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)
//////////////////////////////////////////////////////////////////////////////



//////////////////////////////////////////////////////////////////////////////
const bool useTwoWorkerThreads = true; // ignored for single-threaded builds
//////////////////////////////////////////////////////////////////////////////
// The following example program demonstrates the use of asynchronous state
// machines. First, it creates two objects of the same simple state machine
// mimicking a table tennis player. It then sends an event (the ball) to the
// first state machine. Upon reception, the first machine sends a similar
// event to the second state machine, which then sends the event back to the
// first machine. The two machines continue to bounce the event back and forth
// until one machine "has enough" and aborts the game. The two players don't
// "know" each other, they can only pass the ball back and forth because the
// event representing the ball also carries two boost::function objects.
// Both reference the asynchronous_state_machine<>::queue_event() function of
// the opponent. One can be used to return the ball to the opponent and the
// other can be used to abort the game.
// Depending on whether the program is compiled single-threaded or
// multi-threaded and the useTwoWorkerThreads constant above, the two machines
// either run in the same thread without/with mutex locking or in two
// different threads with mutex locking.
//////////////////////////////////////////////////////////////////////////////



#include <boost/fsm/event.hpp>
#include <boost/fsm/asynchronous_state_machine.hpp>
#include <boost/fsm/simple_state.hpp>
#include <boost/fsm/transition.hpp>
#include <boost/fsm/termination.hpp>
#include <boost/fsm/worker.hpp>

#include <boost/mpl/list.hpp>

#include <boost/intrusive_ptr.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/function.hpp>
#include <boost/bind.hpp>
#include <boost/config.hpp>
#ifdef BOOST_HAS_THREADS
#include <boost/thread/thread.hpp>
#endif

#include <iostream>
#include <ctime>

namespace fsm = boost::fsm;
namespace mpl = boost::mpl;



const unsigned int noOfEvents = 1000000;

template< class T >
boost::intrusive_ptr< T > MakeIntrusive( T * pObject )
{
  return boost::intrusive_ptr< T >( pObject );
}


struct BallReturned : fsm::event< BallReturned >
{
  boost::function1< void, const boost::intrusive_ptr< const BallReturned > & >
    returnToOpponent;
  boost::function0< void > abortGame;
};

struct GameAborted : fsm::event< GameAborted > {};


struct Waiting;
struct Player : fsm::asynchronous_state_machine< Player, Waiting >
{
  typedef fsm::asynchronous_state_machine< Player, Waiting > BaseType;
  public:
    Player( fsm::worker<> & myWorker, unsigned int maxNoOfReturns ) :
      BaseType( myWorker ),
      maxNoOfReturns_( maxNoOfReturns ),
      noOfReturns_( 0 ),
      pBallReturned_( new BallReturned() )
    {
      // as we will always return the same event to the opponent, we construct
      // and fill it here so that we can reuse it over and over
      pBallReturned_->returnToOpponent =
        boost::bind( &Player::queue_event, &context< Player >(), _1 );
      pBallReturned_->abortGame = boost::bind( &Player::queue_event, 
        &context< Player >(), MakeIntrusive( new GameAborted() ) );
    }

    void ReturnToOpponent( const BallReturned & ballReturned )
    {
      ++totalNoOfProcessedEvents_;

      if ( noOfReturns_++ < maxNoOfReturns_ )
      {
        ballReturned.returnToOpponent( pBallReturned_ );
      }
      else
      {
        ballReturned.abortGame();
        post_event(
          boost::intrusive_ptr< GameAborted >( new GameAborted() ) );
      }
    }

    static unsigned int GetTotalNoOfProcessedEvents()
    {
      return totalNoOfProcessedEvents_;
    }

  private:
    static unsigned int totalNoOfProcessedEvents_;
    const unsigned int maxNoOfReturns_;
    unsigned int noOfReturns_;
    const boost::intrusive_ptr< BallReturned > pBallReturned_;
};

unsigned int Player::totalNoOfProcessedEvents_ = 0;


struct Waiting : fsm::simple_state< Waiting, Player, mpl::list<
  fsm::transition< BallReturned, Waiting, Player, &Player::ReturnToOpponent >,
  fsm::termination< GameAborted > > >
{
};



char GetKey()
{
  char key;
  std::cin >> key;
  return key;
}

int main()
{
  std::cout << "boost::fsm PingPong example\n\n";
  std::cout << "Threading configuration:\n";
  #ifdef BOOST_HAS_THREADS
  std::cout << "Multi-threaded build with " <<
    ( useTwoWorkerThreads ? 2 : 1 ) << " worker thread(s).\n";
  #else
  std::cout << "Single-threaded build\n";
  #endif
  
  std::cout << "\np<CR>: Performance test\n";
  std::cout << "e<CR>: Exits the program\n\n";

  char key = GetKey();

  while ( key != 'e' )
  {
    switch( key )
    {
      case 'p':
      {
        fsm::worker<> worker1;
        fsm::worker<> worker2;

        Player player1( worker1, noOfEvents / 2 );
        boost::shared_ptr< Player > pPlayer2;

        #ifdef BOOST_MSVC
        #pragma warning( push )
        #pragma warning( disable: 4127 )
        #endif

        if ( useTwoWorkerThreads )
        {
          #ifdef BOOST_HAS_THREADS
          pPlayer2 = boost::shared_ptr< Player >(
            new Player( worker2, noOfEvents / 2 ) );
          #else
          pPlayer2 = boost::shared_ptr< Player >(
            new Player( worker1, noOfEvents / 2 ) );
          #endif
        }
        else
        {
          pPlayer2 = boost::shared_ptr< Player >(
            new Player( worker1, noOfEvents / 2 ) );
        }

        #ifdef BOOST_MSVC
        #pragma warning( pop )
        #endif

        boost::intrusive_ptr< BallReturned > pInitialBall = new BallReturned();
        pInitialBall->returnToOpponent =
          boost::bind( &Player::queue_event, &player1, _1 );
        pInitialBall->abortGame = boost::bind( &Player::queue_event, 
          &player1, MakeIntrusive( new GameAborted() ) );
        pPlayer2->queue_event( pInitialBall );

        std::cout << "\nHaving players return the ball " <<
          noOfEvents << " times. Please wait...\n";

        const unsigned int prevCount = Player::GetTotalNoOfProcessedEvents();
        const std::clock_t startTime = std::clock();

        #ifdef BOOST_MSVC
        #pragma warning( push )
        #pragma warning( disable: 4127 )
        #endif

        if ( useTwoWorkerThreads )
        {
          #ifdef BOOST_HAS_THREADS
          boost::thread otherThread(
            boost::bind( &fsm::worker<>::operator(), &worker2 ) );
          worker1();
          otherThread.join();
          #else
          worker1();
          #endif
        }
        else
        {
          worker1();
        }

        #ifdef BOOST_MSVC
        #pragma warning( pop )
        #endif

        const std::clock_t elapsedTime = std::clock() - startTime;
        std::cout << "Time to send and dispatch one event and\n" <<
                     "perform the resulting transition: ";
        std::cout << elapsedTime * 1000.0 /
          ( Player::GetTotalNoOfProcessedEvents() - prevCount ) << " microseconds\n\n";
      }
      break;

      default:
      {
        std::cout << "Invalid key!\n";
      }
    }

    key = GetKey();
  }

  return 0;
}