Utils.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
#pragma once
 
#include <TBranch.h>
 
#include <string>
#include <sstream>
#include <functional>
 
namespace Belle2 {
  namespace Utils {

    template<class... Ts> struct VisitOverload : Ts... { using Ts::operator()...; };
    template<class... Ts> VisitOverload(Ts...) -> VisitOverload<Ts...>;

    template<class T>
    T reduceTBranch(TBranch* branch, const std::function<T(T, T)>& f, T reduced = T())
    {
      T object;
      branch->SetAddress(&object);
      int nevents = branch->GetEntries();
      for (int i = 0; i < nevents; ++i) {
        branch->GetEvent(i);
        reduced = f(reduced, object);
      }
      return reduced;
    }
 

    double getClock();

    double getCPUClock();

    unsigned long getVirtualMemoryKB();

    unsigned long getRssMemoryKB();

    class Timer {
    public:
      explicit Timer(std::string  text = "");
      ~Timer();
    private:
      double m_startTime; 
      std::string m_text; 
    };

    std::string getCommandOutput(const std::string& command, const std::vector<std::string>& arguments = {}, bool searchPath = true);
  }

#define B2INFO_MEASURE_TIME(txt, ...) {\
    std::stringstream __b2_timer_str__;\
    __b2_timer_str__ << txt;\
    ::Belle2::Utils::Timer __b2_timer__(__b2_timer_str__.str());\
    {__VA_ARGS__;}\
  }

#if defined(__GNUC__) || defined(__ICL) || defined(__clang__)
#define branch_likely(x)       __builtin_expect(!!(x), 1)
#define branch_unlikely(x)     __builtin_expect(!!(x), 0)
#else
#define branch_likely(x)       (x)
#define branch_unlikely(x)     (x)
#endif

} // Belle2 namespace