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       1             : // -*- C++ -*-
       2             : //# ThreadCoordinator.h: Definition of the ThreadCoordinator class
       3             : //# Copyright (C) 1997,1998,1999,2000,2001,2002,2003
       4             : //# Associated Universities, Inc. Washington DC, USA.
       5             : //#
       6             : //# This library is free software; you can redistribute it and/or modify it
       7             : //# under the terms of the GNU Library General Public License as published by
       8             : //# the Free Software Foundation; either version 2 of the License, or (at your
       9             : //# option) any later version.
      10             : //#
      11             : //# This library is distributed in the hope that it will be useful, but WITHOUT
      12             : //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
      13             : //# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
      14             : //# License for more details.
      15             : //#
      16             : //# You should have received a copy of the GNU Library General Public License
      17             : //# along with this library; if not, write to the Free Software Foundation,
      18             : //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
      19             : //#
      20             : //# Correspondence concerning AIPS++ should be addressed as follows:
      21             : //#        Internet email: aips2-request@nrao.edu.
      22             : //#        Postal address: AIPS++ Project Office
      23             : //#                        National Radio Astronomy Observatory
      24             : //#                        520 Edgemont Road
      25             : //#                        Charlottesville, VA 22903-2475 USA
      26             : //#
      27             : //# $Id$
      28             : 
      29             : #include <casacore/casa/aips.h>
      30             : #include <casacore/casa/aipstype.h>
      31             : #include <cstddef>
      32             : 
      33             : //<example>
      34             : //
      35             : // Code in the master thread:
      36             : //
      37             : //    ThreadCoordinator threadCoordinator (nThreads);
      38             : //
      39             : //    // Create nThread threads and pass them a pointer to the thread coordinator
      40             : //    // object.  Then enter the work loop
      41             : //    
      42             : //    for (int i = 0; i < nBuffers; i++){
      43             : //    
      44             : //      // Provide access to the i-th buffer
      45             : //    
      46             : //      threadCoordinator->getToWork(& vb); // tell workers to hop to it!
      47             : //                                          // blocks if workers still busy
      48             : //    
      49             : //     }
      50             : //    
      51             : // Code in each worker thread:
      52             : //    
      53             : //    while (true){
      54             : //    
      55             : //      VisBuffer * workingBuffer = threadCoordinator_p->waitForWork (this);
      56             : //      if (workingBuffer == NULL)
      57             : //        break;
      58             : //    
      59             : //      doSomeWork(workingBuffer);
      60             : //     }
      61             : // </example>
      62             : 
      63             : #ifndef SYNTHESIS_THREADCOORDINATOR_H
      64             : #define SYNTHESIS_THREADCOORDINATOR_H
      65             : 
      66             : namespace casacore{
      67             : 
      68             :   class Mutex;
      69             : class String;
      70             : }
      71             : 
      72             : namespace casa {
      73             : 
      74             : class Barrier;
      75             : 
      76             : namespace async {
      77             :   class Condition;
      78             :   class Mutex;
      79             :   class Thread;
      80             : }
      81             : 
      82             : class VisBuffer;
      83             : 
      84             : class ThreadCoordinatorBase {
      85             : 
      86             : public:
      87             : 
      88             :   virtual ~ThreadCoordinatorBase ();
      89             : 
      90             :   void waitForWorkersToFinishTask ();
      91             : 
      92             : protected:
      93             : 
      94             :   ThreadCoordinatorBase (casacore::Int nThreads, bool logStates);
      95             : 
      96             : 
      97             :   void dispatchWork ();
      98             :   void getToWork ();
      99             :   virtual void installWorkInfo () = 0;
     100             :   bool waitForWork (const async::Thread * thisThread);
     101             :   void waitForWorkersToReport ();
     102             :   casacore::Int nThreads_p;
     103             : 
     104             : 
     105             : private:
     106             : 
     107             :   Barrier * barrier_p;
     108             :   bool logStates_p;
     109             :   async::Mutex * mutex_p;
     110             :   volatile casacore::Int nThreadsAtBarrier_p;
     111             :   volatile casacore::Int nThreadsDispatched_p;
     112             :   volatile casacore::Bool readyForWork_p;
     113             :   async::Condition * stateChanged_p;
     114             :   //const VisBuffer * vb_p;
     115             :   volatile bool workCompleted_p;
     116             :   volatile bool workToBeDone_p;
     117             : 
     118             :   void logState (const casacore::String & tag) const;
     119             : 
     120             : };
     121             : 
     122             : template <typename T>
     123             : class ThreadCoordinator : public ThreadCoordinatorBase {
     124             : 
     125             : public:
     126             : 
     127           0 :     ThreadCoordinator (casacore::Int nThreads, casacore::Bool logStates = false) : ThreadCoordinatorBase (nThreads, logStates) {}
     128             : 
     129             :     void
     130           0 :     giveWorkToWorkers (T * workInfo)
     131             :     {
     132           0 :         workInfoInWaiting_p = workInfo;
     133           0 :         waitForWorkersToReport ();
     134           0 :         dispatchWork ();
     135           0 :     }
     136             : 
     137             :     void
     138             :     getToWork (T * workInfo)
     139             :     {
     140             :         workInfoInWaiting_p = workInfo;
     141             :         ThreadCoordinatorBase::getToWork ();
     142             :     }
     143             : 
     144             :     T *
     145           0 :     waitForWork (const async::Thread * thisThread)
     146             :     {
     147           0 :         bool ok = ThreadCoordinatorBase::waitForWork (thisThread);
     148           0 :         T * result = ok ? workInfo_p : NULL;
     149             : 
     150           0 :         return result;
     151             :     }
     152             : 
     153           0 :    void setNThreads(casacore::Int n) {nThreads_p=n;};
     154           0 :    casacore::Int nThreads() {return nThreads_p;};
     155             : protected:
     156             : 
     157             :     void
     158           0 :     installWorkInfo ()
     159             :     {
     160           0 :         workInfo_p = workInfoInWaiting_p;
     161           0 :         workInfoInWaiting_p = NULL;
     162           0 :     }
     163             : 
     164             : 
     165             : private:
     166             : 
     167             :     T * workInfoInWaiting_p;
     168             :     T * workInfo_p;
     169             : };
     170             : 
     171             : } // end namespace casa
     172             : 
     173             : #endif //