TRandomTLS.h

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/*
 * Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration.
 */
 
#ifndef ROOTUTILS_TRANDOMTLS_H
#define ROOTUTILS_TRANDOMTLS_H
 
#include <atomic>
 
#include "Rtypes.h"
#include "boost/thread/tss.hpp"
 
namespace RootUtils {

  template <class T>
  class TRandomTLS {
  public:
    TRandomTLS(UInt_t seed = 4357) : m_seed(seed) {}

    ~TRandomTLS() = default;

    T* get() const;
    T* operator->() const { return get(); }
    T& operator*() const { return *get(); }
 
  private:
    mutable boost::thread_specific_ptr<T> m_rand_tls;

    mutable std::atomic<UInt_t> m_seed;
  };
 
 
  //
  // Inline methods
  //
 
  template <class T>
  inline T* TRandomTLS<T>::get() const
  {
    T* random = m_rand_tls.get();
    if (!random) {
      random = new T(m_seed > 0 ? m_seed++ : 0);
      m_rand_tls.reset(random);
    }
    return random;
  }
 
} // namespace RootUtils
 
#endif