Program Listing for File allocation_statistics.cpp

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//////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2016-20, Lawrence Livermore National Security, LLC and Umpire
// project contributors. See the COPYRIGHT file for details.
//
// SPDX-License-Identifier: (MIT)
//////////////////////////////////////////////////////////////////////////////

#include "umpire/util/allocation_statistics.hpp"

#include <algorithm>

namespace umpire {
namespace util {

float relative_fragmentation(std::vector<util::AllocationRecord>& recs)
{
  auto r1 = recs.begin();
  auto r2 = recs.begin(); ++r2;
  std::size_t largest_free_space = 0;
  std::size_t total_free_space = 0;
  while (r2 != recs.end()) {
    const std::size_t free_space =
      reinterpret_cast<char*>(r2->ptr) - (reinterpret_cast<char*>(r1->ptr) + r1->size);
    largest_free_space = std::max(largest_free_space, free_space);
    total_free_space += free_space;
  }

  return 1.0f - static_cast<float>(largest_free_space) / total_free_space;
}

}
}