IOMCTruthContainerView.h

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// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
 
 
#ifndef ALICEO2_DATAFORMATS_IOMCTRUTHVIEW_H_
#define ALICEO2_DATAFORMATS_IOMCTRUTHVIEW_H_
 
#include "GPUCommonRtypes.h" // to have the ClassDef macros
#include <vector>
#include <gsl/span>
 
namespace o2
{
namespace dataformats
{
 
class IOMCTruthContainerView
{
 public:
  IOMCTruthContainerView() = default;
 
  IOMCTruthContainerView(std::vector<char> const& input)
  {
    adopt(gsl::span<const char>(&(input[0]), input.size()));
  }
 
  IOMCTruthContainerView(gsl::span<const char> const input)
  {
    adopt(input);
  }
 
  ~IOMCTruthContainerView()
  {
    if (!mIsView) {
      delete[] part1;
      delete[] part2;
      delete[] part3;
      delete[] part4;
      delete[] part5;
      delete[] part6;
      delete[] part7;
      delete[] part8;
      delete[] part9;
      delete[] part10;
    }
  }
 
  void adopt(gsl::span<const char> const input)
  {
    mIsView = true;
    const auto delta = input.size() / N;
    N2 = input.size() - (N - 1) * delta;
    N1 = delta;
    // TODO: this could benefit from a loop expansion
    part1 = &input[0];
    part2 = &input[delta];
    part3 = &input[2 * delta];
    part4 = &input[3 * delta];
    part5 = &input[4 * delta];
    part6 = &input[5 * delta];
    part7 = &input[6 * delta];
    part8 = &input[7 * delta];
    part9 = &input[8 * delta];
    part10 = &input[9 * delta];
  }
 
  template <typename Alloc>
  void copyandflatten(std::vector<char, Alloc>& output) const
  {
    // TODO: this could benefit from a loop expansion
    copyhelper(part1, N1, output);
    copyhelper(part2, N1, output);
    copyhelper(part3, N1, output);
    copyhelper(part4, N1, output);
    copyhelper(part5, N1, output);
    copyhelper(part6, N1, output);
    copyhelper(part7, N1, output);
    copyhelper(part8, N1, output);
    copyhelper(part9, N1, output);
    copyhelper(part10, N2, output);
  }
 
  size_t getSize() const { return N1 * (N - 1) + N2; }
 
 private:
  static constexpr int N = 10;
  int N1 = 0;
  int N2 = 0;
  const char* part1 = nullptr;  //[N1]
  const char* part2 = nullptr;  //[N1]
  const char* part3 = nullptr;  //[N1]
  const char* part4 = nullptr;  //[N1]
  const char* part5 = nullptr;  //[N1]
  const char* part6 = nullptr;  //[N1]
  const char* part7 = nullptr;  //[N1]
  const char* part8 = nullptr;  //[N1]
  const char* part9 = nullptr;  //[N1]
  const char* part10 = nullptr; //[N2]
 
  bool mIsView = false; 
                        //  we need to know this for the destructor
 
  template <typename Alloc>
  void copyhelper(const char* input, int size, std::vector<char, Alloc>& output) const
  {
    gsl::span<const char> tmp(input, size);
    std::copy(tmp.begin(), tmp.end(), std::back_inserter(output));
  }
 
  ClassDefNV(IOMCTruthContainerView, 1);
};
} // namespace dataformats
} // namespace o2
 
#endif