SmallArray.cc

// -*- tab-width: 2; indent-tabs-mode: nil; coding: utf-8-with-signature -*-
//-----------------------------------------------------------------------------
// Copyright 2000-2023 CEA (www.cea.fr) IFPEN (www.ifpenergiesnouvelles.com)
// See the top-level COPYRIGHT file for details.
// SPDX-License-Identifier: Apache-2.0
//-----------------------------------------------------------------------------
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/* SmallArray.cc                                               (C) 2000-2023 */
/*                                                                           */
/* Tableau 1D de données avec buffer pré-alloué.                             */
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#include "arcane/utils/SmallArray.h"
 
#include <cstdlib>
#include <cstring>
 
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namespace Arcane::impl
{
 
namespace
{
//! A mettre à true si on souhaite activer les traces d'allocation
const bool is_verbose = false;
}
 
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bool StackMemoryAllocator::
hasRealloc() const
{
  return true;
}
 
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void* StackMemoryAllocator::
allocate(size_t new_size)
{
  if (new_size <= m_preallocated_size) {
    if (is_verbose)
      std::cout << "ALLOCATE: use preallocated s=" << new_size << "\n";
    return m_preallocated_buffer;
  }
 
  if (is_verbose)
    std::cout << "ALLOCATE: use malloc s=" << new_size << "\n";
  return std::malloc(new_size);
}
 
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void* StackMemoryAllocator::
reallocate(void* current_ptr, size_t new_size)
{
  if (current_ptr != m_preallocated_buffer) {
    if (new_size < m_preallocated_size) {
      // On passe d'un pointeur alloué vers notre buffer interne.
      // Il faut recopier les valeurs. On ne connait pas exactement
      // la taille de 'current_ptr' mais on est certain qu'elle est
      // supérieure à 'm_preallocated_size' donc à 'new_size'.
      // On ne recopie donc que ces valeurs là
      if (is_verbose)
        std::cout << "REALLOCATE: use own buffer from realloc s=" << new_size << "\n";
      std::memcpy(m_preallocated_buffer, current_ptr, new_size);
      std::free(current_ptr);
      return m_preallocated_buffer;
    }
    if (is_verbose)
      std::cout << "REALLOCATE: use realloc s=" << new_size << "\n";
    return std::realloc(current_ptr, new_size);
  }
 
  if (new_size <= m_preallocated_size) {
    if (is_verbose)
      std::cout << "REALLOCATE: use buffer because small size s=" << new_size << "\n";
    return m_preallocated_buffer;
  }
 
  // Il faut allouer et recopier depuis le buffer pré-alloué.
  if (is_verbose)
    std::cout << "REALLOCATE: use malloc and copy s=" << new_size << "\n";
  void* new_ptr = std::malloc(new_size);
  std::memcpy(new_ptr, m_preallocated_buffer, m_preallocated_size);
  return new_ptr;
}
 
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void StackMemoryAllocator::
deallocate(void* ptr)
{
  if (ptr != m_preallocated_buffer)
    std::free(ptr);
}
 
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} // namespace Arcane
 
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