SphinxExamples/src/Core/Common/TraceMemoryBetweenPoints/Code.cxx

/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
 
#include "itkMemoryProbe.h"
#include <iostream>
 
int
main(int argc, char * argv[])
{
  if (argc != 2)
  {
    std::cerr << "Usage:" << std::endl;
    std::cerr << argv[0] << " <Size of the array>" << std::endl;
    return EXIT_FAILURE;
  }
 
  const auto N = static_cast<unsigned int>(std::stoi(argv[1]));
 
  if (N == 0)
  {
    std::cerr << "Size of the array should be non null" << std::endl;
    return EXIT_FAILURE;
  }
 
  itk::MemoryProbe memoryProbe;
 
  memoryProbe.Start();
  std::cout << "We are measuring " << memoryProbe.GetType();
  std::cout << " in units of " << memoryProbe.GetUnit() << ".\n" << std::endl;
  memoryProbe.Stop();
 
  // Expect zeros here
  std::cout << "** Start **" << std::endl;
  std::cout << "Mean: " << memoryProbe.GetMean() << std::endl;
  std::cout << "Total: " << memoryProbe.GetTotal() << std::endl;
  std::cout << std::endl;
 
  memoryProbe.Start();
  auto * a = new char[N];
  // The memory must be used for it to be counted.
  for (unsigned int i = 0; i < N; ++i)
  {
    a[i] = static_cast<char>(i * i);
  }
  memoryProbe.Stop();
 
  std::cout << "** After allocation **" << std::endl;
  std::cout << "Mean: " << memoryProbe.GetMean() << std::endl;
  std::cout << "Total: " << memoryProbe.GetTotal() << std::endl;
  std::cout << std::endl;
 
  memoryProbe.Start();
  delete[] a;
  memoryProbe.Stop();
 
  std::cout << "** After deallocation **" << std::endl;
  std::cout << "Mean: " << memoryProbe.GetMean() << std::endl;
  std::cout << "Total: " << memoryProbe.GetTotal() << std::endl;
 
  return EXIT_SUCCESS;
}