thread_local_storage.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2011 - 2017 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE at
// the top level of the deal.II distribution.
//
// ---------------------------------------------------------------------

#ifndef dealii_thread_local_storage_h
#define dealii_thread_local_storage_h


#include <deal.II/base/config.h>

#ifdef DEAL_II_WITH_THREADS
#  include <tbb/enumerable_thread_specific.h>
#endif



DEAL_II_NAMESPACE_OPEN



namespace Threads
{
  template <typename T>
  class ThreadLocalStorage
  {
  public:
    ThreadLocalStorage () = default;

    explicit ThreadLocalStorage (const T &t);

    ThreadLocalStorage (const ThreadLocalStorage<T> &t);

    T &get ();

    T &get (bool &exists);

    operator T &();

    ThreadLocalStorage<T> &operator = (const T &t);

    void clear ();

#ifdef DEAL_II_WITH_THREADS
    tbb::enumerable_thread_specific<T> &
#else
    T &
#endif
    get_implementation();

  private:
#ifdef DEAL_II_WITH_THREADS

    tbb::enumerable_thread_specific<T> data;
#else
    T data;
#endif
  };

// ----------------- inline and template functions ----------------------------

  template <typename T>
  inline
  ThreadLocalStorage<T>::ThreadLocalStorage(const T &t)
    :
    data (t)
  {}


  template <typename T>
  inline
  ThreadLocalStorage<T>::ThreadLocalStorage(const ThreadLocalStorage<T> &t)
    :
    data (t)
  {}


  template <typename T>
  inline
  T &
  ThreadLocalStorage<T>::get ()
  {
#ifdef DEAL_II_WITH_THREADS
    return data.local();
#else
    return data;
#endif
  }


  template <typename T>
  inline
  T &
  ThreadLocalStorage<T>::get (bool &exists)
  {
#ifdef DEAL_II_WITH_THREADS
    return data.local(exists);
#else
    exists = true;
    return data;
#endif
  }


  template <typename T>
  inline
  ThreadLocalStorage<T>::operator T &()
  {
    return get();
  }


  template <typename T>
  inline
  ThreadLocalStorage<T> &
  ThreadLocalStorage<T>::operator = (const T &t)
  {
    get() = t;
    return *this;
  }


  template <typename T>
  inline
#ifdef DEAL_II_WITH_THREADS
  tbb::enumerable_thread_specific<T> &
#else
  T &
#endif
  ThreadLocalStorage<T>::get_implementation()
  {
    return data;
  }



  template <typename T>
  inline
  void
  ThreadLocalStorage<T>::clear ()
  {
#ifdef DEAL_II_WITH_THREADS
    data.clear ();
#else
    data = T {};
#endif
  }
}   // end of implementation of namespace Threads

//---------------------------------------------------------------------------
DEAL_II_NAMESPACE_CLOSE
// end of #ifndef dealii_thread_local_storage_h
#endif
//---------------------------------------------------------------------------