geant4/examples/extended/parallel/ThreadsafeScorers/include/G4TAtomicHitsCollection.hh

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/// \file G4TAtomicHitsCollection.hh
/// \brief Definition of the G4TAtomicHitsCollection class
///
/// This is an implementation of G4THitsCollection<T> where the underlying
///     type is G4atomic<T>, not just T. A static assert is provided to
///     ensure that T is fundamental. This class should be used in lieu
///     of G4THitsCollection<T> when memory is a concern. Atomics are
///     thread-safe and *generally* faster that mutexes (as long as the
///     STL implementation is lock-free) but the synchronization does
///     not come without a cost. If performance is the primary concern,
///     use G4THitsCollection<T> in thread-local instances.
//
//
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#ifndef G4TAtomicHitsCollection_h
#define G4TAtomicHitsCollection_h 1

#include "G4Allocator.hh"
#include "G4AutoLock.hh"
#include "G4Threading.hh"
#include "G4VHitsCollection.hh"
#include "G4atomic.hh"
#include "globals.hh"

#include <deque>
#include <type_traits>

/// class description:
///
///  This is a template class of hits collection and parametrized by
/// The concrete class of G4VHit. This is a uniform collection for
/// a particular concrete hit class objects.
///  An intermediate layer class G4HitsCollection appeared in this
/// header file is used just for G4Allocator, because G4Allocator
/// cannot be instansiated with a template class. Thus G4HitsCollection
/// class MUST NOT be directly used by the user.

/*class G4HitsCollection : public G4VHitsCollection
{
  public:
      G4HitsCollection();
      G4HitsCollection(G4String detName,G4String colNam);
      virtual ~G4HitsCollection();
      G4bool operator==(const G4HitsCollection &right) const;

  protected:
      void* theCollection;
};*/

template<class T>
class G4TAtomicHitsCollection : public G4VHitsCollection
{
  protected:
    static_assert(std::is_fundamental<T>::value,
                  "G4TAtomicHitsCollection must use fundamental type");

  public:
    typedef T base_type;
    typedef G4atomic<T> value_type;
    typedef typename std::deque<value_type*> container_type;

  public:
    G4TAtomicHitsCollection();

  public:
    // with description
    G4TAtomicHitsCollection(G4String detName, G4String colNam);

    // constructor.
  public:
    virtual ~G4TAtomicHitsCollection();
    G4bool operator==(const G4TAtomicHitsCollection<T>& right) const;

    // inline void *operator new(size_t);
    // inline void operator delete(void* anHC);

  public:  // with description
    virtual void DrawAllHits();
    virtual void PrintAllHits();
    //  These two methods invokes Draw() and Print() methods of all of
    // hit objects stored in this collection, respectively.

  public:  // with description
    inline value_type* operator[](size_t i) const { return (*theCollection)[i]; }
    //  Returns a pointer to a concrete hit object.
    inline container_type* GetVector() const { return theCollection; }
    //  Returns a collection vector.
    inline G4int insert(T* aHit)
    {
      G4AutoLock l(&fMutex);
      theCollection->push_back(aHit);
      return theCollection->size();
    }
    //  Insert a hit object. Total number of hit objects stored in this
    // collection is returned.
    inline G4int entries() const
    {
      G4AutoLock l(&fMutex);
      return theCollection->size();
    }
    //  Returns the number of hit objects stored in this collection

  public:
    virtual G4VHit* GetHit(size_t i) const { return (*theCollection)[i]; }
    virtual size_t GetSize() const
    {
      G4AutoLock l(&fMutex);
      return theCollection->size();
    }

  protected:
    container_type* theCollection;
    G4Mutex fMutex;
};

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template<class T>
G4TAtomicHitsCollection<T>::G4TAtomicHitsCollection() : theCollection(new container_type)
{}
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template<class T>
G4TAtomicHitsCollection<T>::G4TAtomicHitsCollection(G4String detName, G4String colNam)
  : G4VHitsCollection(detName, colNam), theCollection(new container_type)
{}
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template<class T>
G4TAtomicHitsCollection<T>::~G4TAtomicHitsCollection()
{
  for (size_t i = 0; i < theCollection->size(); i++)
    delete (*theCollection)[i];
  theCollection->clear();
  delete theCollection;
}
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template<class T>
G4bool G4TAtomicHitsCollection<T>::operator==(const G4TAtomicHitsCollection<T>& right) const
{
  return (collectionName == right.collectionName);
}
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template<class T>
void G4TAtomicHitsCollection<T>::DrawAllHits()
{
  G4AutoLock l(&fMutex);
  for (size_t i = 0; i < theCollection->size(); i++)
    (*theCollection)[i]->Draw();
}
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template<class T>
void G4TAtomicHitsCollection<T>::PrintAllHits()
{
  G4AutoLock l(&fMutex);
  for (size_t i = 0; i < theCollection->size(); i++)
    (*theCollection)[i]->Print();
}
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#endif