MultiReadSingleWriteSemaphore.h

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// This file is part of the Peano project. For conditions of distribution and
// use, please see the copyright notice at www.peano-framework.org
#pragma once
 
#include "tarch/multicore/multicore.h"
#include "tarch/multicore/BooleanSemaphore.h"
 
 
namespace tarch {
  namespace multicore {
    class MultiReadSingleWriteSemaphore;
    class MultiReadSingleWriteLock;
  }
}
 
 
#if defined(SharedTBB) or defined(SharedTBBExtension)
#include "tarch/multicore/tbb/MultiReadSingleWriteSemaphore.h"
#else
 
class tarch::multicore::MultiReadSingleWriteSemaphore {
  private:
    friend class tarch::multicore::MultiReadSingleWriteLock;
 
    const bool        _highPriorityToWrites;
    BooleanSemaphore  _semaphore;
    volatile bool     _writeAccessAcquired;
    volatile int      _numberOfPendingWriteRequests;
    volatile int      _numberOfActiveReadAccesses;
 
    void enterCriticalReadSection();
    void enterCriticalWriteSection();
 
    void leaveCriticalReadSection();
    void leaveCriticalWriteSection();
 
    MultiReadSingleWriteSemaphore( const MultiReadSingleWriteSemaphore& ) = delete;
 
    MultiReadSingleWriteSemaphore& operator = ( const MultiReadSingleWriteSemaphore& ) { return *this; }
 
  public:
    MultiReadSingleWriteSemaphore(bool highPriorityToWrites = true);
    ~MultiReadSingleWriteSemaphore();
 
    using Lock = tarch::multicore::MultiReadSingleWriteLock;
};
 
#endif