CallNTimesNoWait.h

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#ifndef FWCore_Utilities_CallNTimesNoWait_h
#define FWCore_Utilities_CallNTimesNoWait_h
// -*- C++ -*-
//
// Package:     FWCore/Utilities
// Class  :     CallNTimesNoWait
// 
//
// Original Author:  Chris Jones
//         Created:  Fri, 15 Nov 2013 14:29:41 GMT
//

// system include files
#include<atomic>

// user include files

// forward declarations
namespace edm {
  class CallNTimesNoWait
  {
    
  public:
    CallNTimesNoWait( unsigned short iNTimes ): m_ntimes(static_cast<int>(iNTimes)-1), m_done(false){}
    
    template <typename T>
    void operator()(T iCall) {
      if(not m_done.load(std::memory_order_acquire) ) {
        if(m_ntimes.fetch_sub(1,std::memory_order_acq_rel)<0) {
          m_done.store(true,std::memory_order_release);
          return;
        };
        iCall();
      }
    }
    
    private:
    std::atomic<int> m_ntimes;
    std::atomic<bool> m_done;
  };
}

#endif