ItemInternalVectorView.h

// -*- tab-width: 2; indent-tabs-mode: nil; coding: utf-8-with-signature -*-
//-----------------------------------------------------------------------------
// Copyright 2000-2026 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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/* ItemInternalVectorView.h                                    (C) 2000-2024 */
/*                                                                           */
/* View on a vector (indirect array) of entities.                            */
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#ifndef ARCANE_CORE_ITEMINTERNALVECTORVIEW_H
#define ARCANE_CORE_ITEMINTERNALVECTORVIEW_H
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#include "arcane/utils/ArrayView.h"
#include "arcane/core/ItemTypes.h"
#include "arcane/core/ItemSharedInfo.h"
#include "arcane/core/ItemIndexedListView.h"
 
#include <iterator>
 
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namespace Arcane
{
 
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/*!
 * \internal
 * \brief Iterator for an ItemInternalVectorView.
 * \deprecated Use an iterator from an ItemVectorView.
 */
class ItemInternalVectorViewConstIterator
{
  friend class ItemInternalVectorView;
  template <int Extent> friend class ItemConnectedListView;
  typedef ItemInternal* ItemInternalPtr;
 
 private:
 
  ItemInternalVectorViewConstIterator(const ItemInternalPtr* items,
                                      const Int32* ARCANE_RESTRICT local_ids,
                                      Integer index, Int32 local_id_offset)
  : m_items(items)
  , m_local_ids(local_ids)
  , m_index(index)
  , m_local_id_offset(local_id_offset)
  {}
 
 public:
 
  typedef ItemInternalVectorViewConstIterator ThatClass;
 
 public:
 
  typedef std::random_access_iterator_tag iterator_category;
  //! Type indexing the array
  typedef const ItemInternalPtr* pointer;
  //! Type indexing the array
  typedef const ItemInternalPtr& reference;
  //! Type indexing the array
  typedef ItemInternalPtr value_type;
  //! Type indexing the array
  typedef Integer size_type;
  //! Type of a difference between iterator elements in the array
  typedef Integer difference_type;
 
 public:
 
  value_type operator*() const { return m_items[m_local_id_offset + m_local_ids[m_index]]; }
  value_type operator->() const { return m_items[m_local_id_offset + m_local_ids[m_index]]; }
  ThatClass& operator++()
  {
    ++m_index;
    return (*this);
  }
  ThatClass& operator--()
  {
    --m_index;
    return (*this);
  }
  void operator+=(difference_type v) { m_index += v; }
  void operator-=(difference_type v) { m_index -= v; }
  friend Integer operator-(const ThatClass& a, const ThatClass& b)
  {
    return a.m_index - b.m_index;
  }
  friend ThatClass operator-(const ThatClass& a, difference_type v)
  {
    Integer index = a.m_index - v;
    return ThatClass(a.m_items, a.m_local_ids, index, a.m_local_id_offset);
  }
  friend ThatClass operator+(const ThatClass& a, difference_type v)
  {
    Integer index = a.m_index + v;
    return ThatClass(a.m_items, a.m_local_ids, index, a.m_local_id_offset);
  }
  friend bool operator<(const ThatClass& lhs, const ThatClass& rhs)
  {
    return lhs.m_index <= rhs.m_index;
  }
  friend bool operator==(const ThatClass& lhs, const ThatClass& rhs)
  {
    // TODO: check if these three comparisons cause performance problems.
    // If so, we can only use the last one.
    return lhs.m_items == rhs.m_items && lhs.m_local_ids == rhs.m_local_ids && lhs.m_index == rhs.m_index;
  }
  friend bool operator!=(const ThatClass& lhs, const ThatClass& rhs)
  {
    return !(lhs == rhs);
  }
 
 private:
 
  const ItemInternalPtr* m_items;
  const Int32* ARCANE_RESTRICT m_local_ids;
  Int32 m_index;
  Int32 m_local_id_offset = 0;
};
 
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/*!
 * \internal
 * \brief Internal view on an array of entities.
 *
 * This class is only useful for constructing entity lists used
 * internally by %Arcane. The user version of this class is
 * ItemVectorView.
 *
 * \sa ItemVectorView
 */
class ARCANE_CORE_EXPORT ItemInternalVectorView
{
 public:
 
  friend class ItemVectorView;
  friend class ItemInternalConnectivityList;
  friend class ItemBase;
  friend class ItemEnumeratorBase;
  friend class SimdItemEnumeratorBase;
  friend class ItemInternalEnumerator;
  template <int Extent> friend class ItemConnectedListView;
  friend ItemInternal;
  template <typename T> friend class ItemEnumeratorBaseT;
  using const_iterator = ItemInternalVectorViewConstIterator;
 
 public:
 
  ItemInternalVectorView() = default;
 
 private:
 
  ItemInternalVectorView(ItemSharedInfo* si, Int32ConstArrayView local_ids, Int32 local_id_offset)
  : m_local_ids(local_ids)
  , m_shared_info(si)
  , m_local_id_offset(local_id_offset)
  {
    ARCANE_ASSERT(_isValid(), ("Bad ItemInternalVectorView"));
  }
 
#if 0
  ItemInternalVectorView(ItemSharedInfo* si, const Int32* local_ids, Integer count, Int32 local_id_offset)
  : m_local_ids(count, local_ids)
  , m_shared_info(si)
  , m_local_id_offset(local_id_offset)
  {
    ARCANE_ASSERT(_isValid(), ("Bad ItemInternalVectorView"));
  }
#endif
 
  ItemInternalVectorView(ItemSharedInfo* si, const impl::ItemLocalIdListContainerView& local_ids)
  : m_local_ids(local_ids._idsWithoutOffset())
  , m_shared_info(si)
  , m_local_id_offset(local_ids.m_local_id_offset)
  {
    ARCANE_ASSERT(_isValid(), ("Bad ItemInternalVectorView"));
  }
 
  ItemInternalVectorView(const impl::ItemIndexedListView<DynExtent>& view)
  : m_local_ids(view.constLocalIds())
  , m_shared_info(view.m_shared_info)
  , m_local_id_offset(view.m_local_id_offset)
  {}
 
 public:
 
  //! Number of elements in the vector
  Integer size() const { return m_local_ids.size(); }
 
  // TODO: to be removed
  //! Array of local entity IDs
  Int32ConstArrayView localIds() const { return m_local_ids; }
 
 public:
 
  /*!
   * \brief Accesses the i-th element of the vector.
   *
   * This method is obsolete. You must construct an 'ItemVectorView' instead
   * and use the associated 'operator[]'.
   */
  ARCANE_DEPRECATED_REASON("Y2022: Use ItemVectorView::operator[] instead")
  ItemInternal* operator[](Integer index) const { return m_shared_info->m_items_internal[m_local_ids[index]]; }
 
  //! Array of entities
  ARCANE_DEPRECATED_REASON("Y2022: Do not use this method")
  ItemInternalArrayView items() const { return m_shared_info->m_items_internal; }
 
  ARCANE_DEPRECATED_REASON("Y2022: Use ItemVectorView to iterate")
  const_iterator begin() const
  {
    return const_iterator(_items().data(), m_local_ids.data(), 0, m_local_id_offset);
  }
 
  ARCANE_DEPRECATED_REASON("Y2022: Use ItemVectorView to iterate")
  const_iterator end() const
  {
    return const_iterator(_items().data(), m_local_ids.data(), this->size(), m_local_id_offset);
  }
 
 protected:
 
  Int32 localIdOffset() const { return m_local_id_offset; }
 
 protected:
 
  Int32ConstArrayView m_local_ids;
  ItemSharedInfo* m_shared_info = ItemSharedInfo::nullInstance();
  Int32 m_local_id_offset = 0;
 
 private:
 
  bool _isValid();
  ItemInternalArrayView _items() const { return m_shared_info->m_items_internal; }
};
 
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} // End namespace Arcane
 
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#endif