Span2.h

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// -*- 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
//-----------------------------------------------------------------------------
/*---------------------------------------------------------------------------*/
/* Span2.h                                                     (C) 2000-2025 */
/*                                                                           */
/* View of a 2D array whose dimensions use Int64.                            */
/*---------------------------------------------------------------------------*/
#ifndef ARCCORE_BASE_SPAN2_H
#define ARCCORE_BASE_SPAN2_H
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/*---------------------------------------------------------------------------*/
 
#include "arccore/base/BaseTypes.h"
#include "arccore/base/TraceInfo.h"
#include "arccore/base/Array2View.h"
 
#include <type_traits>
 
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namespace Arcane
{
 
namespace detail
{
  // To indicate that Span2<T>::view() returns an Array2View
  // and Span2<const T>::view() returns a ConstArray2View.
  template <typename T>
  class View2TypeT
  {
   public:
 
    using view_type = Array2View<T>;
  };
  template <typename T>
  class View2TypeT<const T>
  {
   public:
 
    using view_type = ConstArray2View<T>;
  };
} // namespace detail
 
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/*!
 * \ingroup Collection
 *
 * \brief View for a 2D array.
 *
 * Like any view, an instance of this class is only valid as long as
 * the container it originated from does not change its number of elements.
 * The view is non-modifiable if the template argument is of type 'const T'.
 * This class allows accessing and using an array of elements of type \a T
 * in the same way as a standard C array. \a SizeType is the type used
 * to store the number of elements in the array. This can be 'Int32' or 'Int64'.
 */
template <typename T, typename SizeType, SizeType Extent1, SizeType Extent2>
class Span2Impl
{
  using ThatClass = Span2Impl<T, SizeType, Extent1, Extent2>;
 
 public:
 
  using ElementType = T;
  using element_type = ElementType;
  using value_type = typename std::remove_cv<ElementType>::type;
  using index_type = SizeType;
  using difference_type = SizeType;
  using size_type = SizeType;
  using pointer = ElementType*;
  using const_pointer = typename std::add_const<ElementType*>::type;
  using reference = ElementType&;
  using const_reference = const ElementType&;
  using view_type = typename detail::View2TypeT<ElementType>::view_type;
 
  //! Indicates if an 'X' or 'const X' can be converted to a 'T'
  template <typename X>
  using is_same_const_type = std::enable_if_t<std::is_same_v<X, T> || std::is_same_v<std::add_const_t<X>, T>>;
 
 public:
 
  //! Creates a 2D view of dimension [\a dim1_size][\a dim2_size]
  ARCCORE_HOST_DEVICE Span2Impl(pointer ptr, SizeType dim1_size, SizeType dim2_size)
  : m_ptr(ptr)
  , m_dim1_size(dim1_size)
  , m_dim2_size(dim2_size)
  {}
  //! Creates an empty 2D view.
  ARCCORE_HOST_DEVICE Span2Impl()
  : m_ptr(nullptr)
  , m_dim1_size(0)
  , m_dim2_size(0)
  {}
  // Constructor from a ConstArrayView. This is only allowed
  // if T is const.
  template <typename X, typename = std::enable_if_t<std::is_same_v<X, value_type>>>
  Span2Impl(const ConstArray2View<X>& from)
  : m_ptr(from.data())
  , m_dim1_size(from.dim1Size())
  , m_dim2_size(from.dim2Size())
  {}
  // For a Span<const T>, we are allowed to construct from a Span<T>
  template <typename X, typename = std::enable_if_t<std::is_same_v<X, value_type>>>
  ARCCORE_HOST_DEVICE Span2Impl(const Span2<X>& from)
  : m_ptr(from.data())
  , m_dim1_size(from.dim1Size())
  , m_dim2_size(from.dim2Size())
  {}
 
 public:
 
  //! Number of elements in the first dimension
  constexpr ARCCORE_HOST_DEVICE SizeType dim1Size() const { return m_dim1_size; }
  //! Number of elements in the second dimension
  constexpr ARCCORE_HOST_DEVICE SizeType dim2Size() const { return m_dim2_size; }
  //! Total number of elements.
  constexpr ARCCORE_HOST_DEVICE SizeType totalNbElement() const { return m_dim1_size * m_dim2_size; }
 
 public:
 
  constexpr ARCCORE_HOST_DEVICE SpanImpl<ElementType, SizeType> operator[](SizeType i) const
  {
    ARCCORE_CHECK_AT(i, m_dim1_size);
    return SpanImpl<ElementType, SizeType>(m_ptr + (m_dim2_size * i), m_dim2_size);
  }
 
  constexpr ARCCORE_HOST_DEVICE SpanImpl<ElementType, SizeType> operator()(SizeType i) const
  {
    ARCCORE_CHECK_AT(i, m_dim1_size);
    return SpanImpl<ElementType, SizeType>(m_ptr + (m_dim2_size * i), m_dim2_size);
  }
 
  constexpr ARCCORE_HOST_DEVICE reference operator()(SizeType i, SizeType j) const
  {
    ARCCORE_CHECK_AT2(i, j, m_dim1_size, m_dim2_size);
    return m_ptr[(m_dim2_size * i) + j];
  }
 
#ifdef ARCCORE_HAS_MULTI_SUBSCRIPT
  constexpr ARCCORE_HOST_DEVICE reference operator[](SizeType i, SizeType j) const
  {
    ARCCORE_CHECK_AT2(i, j, m_dim1_size, m_dim2_size);
    return m_ptr[(m_dim2_size * i) + j];
  }
#endif
 
  //! Value of the element [\a i][\a j]
  constexpr ARCCORE_HOST_DEVICE ElementType item(SizeType i, SizeType j) const
  {
    ARCCORE_CHECK_AT2(i, j, m_dim1_size, m_dim2_size);
    return m_ptr[(m_dim2_size * i) + j];
  }
 
  //! Positions the element [\a i][\a j] at \a value
  constexpr ARCCORE_HOST_DEVICE ElementType setItem(SizeType i, SizeType j, const ElementType& value)
  {
    ARCCORE_CHECK_AT2(i, j, m_dim1_size, m_dim2_size);
    m_ptr[(m_dim2_size * i) + j] = value;
  }
 
 public:
 
  /*!
   * \brief Constant view of this view.
   */
  constexpr view_type smallView()
  {
    Integer s1 = arccoreCheckArraySize(m_dim1_size);
    Integer s2 = arccoreCheckArraySize(m_dim2_size);
    return view_type(m_ptr, s1, s2);
  }
 
  /*!
   * \brief Constant view of this view.
   */
  constexpr ConstArrayView<value_type> constSmallView() const
  {
    Integer s1 = arccoreCheckArraySize(m_dim1_size);
    Integer s2 = arccoreCheckArraySize(m_dim2_size);
    return ConstArrayView<value_type>(m_ptr, s1, s2);
  }
 
 public:
 
  //! Pointer to the allocated memory.
  constexpr ElementType* unguardedBasePointer() { return m_ptr; }
 
  //! Pointer to the allocated memory.
  constexpr ARCCORE_HOST_DEVICE ElementType* data() { return m_ptr; }
 
  //! Pointer to the allocated memory.
  constexpr ARCCORE_HOST_DEVICE const ElementType* data() const { return m_ptr; }
 
 public:
 
  //! Equality operator (valid if T is const but not X)
  template <typename X, SizeType XExtent1, SizeType XExtent2, typename = std::enable_if_t<std::is_same_v<X, value_type>>>
  friend bool operator==(const ThatClass& lhs, const Span2Impl<X, SizeType, XExtent1, XExtent2>& rhs)
  {
    return impl::areEqual2D(rhs, lhs);
  }
  //! Inequality operator (valid if T is const but not X)
  template <typename X, SizeType XExtent1, SizeType XExtent2, typename = std::enable_if_t<std::is_same_v<X, value_type>>>
  friend bool operator!=(const ThatClass& lhs, const Span2Impl<X, SizeType, XExtent1, XExtent2>& rhs)
  {
    return !impl::areEqual2D(rhs, lhs);
  }
  //! Equality operator
  template <SizeType XExtent1, SizeType XExtent2>
  friend bool operator==(const ThatClass& lhs, const Span2Impl<T, SizeType, XExtent1, XExtent2>& rhs)
  {
    return impl::areEqual2D(rhs, lhs);
  }
  //! Inequality operator
  template <SizeType XExtent1, SizeType XExtent2>
  friend bool operator!=(const ThatClass& lhs, const Span2Impl<T, SizeType, XExtent1, XExtent2>& rhs)
  {
    return !impl::areEqual2D(rhs, lhs);
  }
 
 protected:
 
  ElementType* m_ptr;
  SizeType m_dim1_size;
  SizeType m_dim2_size;
};
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
/*!
 * \ingroup Collection
 *
 * \brief View for a 2D array whose size is an 'Int32'
 *
 * Like any view, an instance of this class is only valid as long as
 * the container it originated from does not change its number of elements.
 */
template <class T, Int32 Extent1, Int32 Extent2>
class SmallSpan2
: public Span2Impl<T, Int32, Extent1, Extent2>
{
  friend class Span2<T>;
 
 public:
 
  using ThatClass = SmallSpan2<T, Extent1, Extent2>;
  using BaseClass = Span2Impl<T, Int32, Extent1, Extent2>;
  using size_type = Int32;
  using value_type = typename BaseClass::value_type;
  using pointer = typename BaseClass::pointer;
  using BaseClass::operator();
  using BaseClass::operator[];
  using ElementType = typename BaseClass::ElementType;
 
 private:
 
  using BaseClass::m_dim1_size;
  using BaseClass::m_dim2_size;
  using BaseClass::m_ptr;
 
 public:
 
  //! Creates a 2D view of dimension [\a dim1_size][\a dim2_size]
  ARCCORE_HOST_DEVICE SmallSpan2(pointer ptr, Int32 dim1_size, Int32 dim2_size)
  : BaseClass(ptr, dim1_size, dim2_size)
  {}
  //! Creates an empty 2D view.
  ARCCORE_HOST_DEVICE SmallSpan2()
  : BaseClass()
  {}
  //! Copy constructor from another view
  SmallSpan2(const Array2View<value_type>& from)
  : BaseClass(from.m_ptr, from.dim1Size(), from.dim2Size())
  {}
  // Constructor from a ConstArrayView. This is only allowed
  // if T is const.
  template <typename X, typename = std::enable_if_t<std::is_same_v<X, value_type>>>
  SmallSpan2(const ConstArray2View<X>& from)
  : BaseClass(from.m_ptr, from.dim1Size(), from.dim2Size())
  {}
  // For a Span<const T>, we are allowed to construct from a Span<T>
  template <typename X, typename = std::enable_if_t<std::is_same_v<X, value_type>>>
  ARCCORE_HOST_DEVICE SmallSpan2(const SmallSpan2<X>& from)
  : BaseClass(from.data(), from.dim1Size(), from.dim2Size())
  {}
 
 public:
 
  ARCCORE_HOST_DEVICE SmallSpan<ElementType> operator[](Int32 i) const
  {
    ARCCORE_CHECK_AT(i, m_dim1_size);
    return SmallSpan<ElementType>(m_ptr + (m_dim2_size * i), m_dim2_size);
  }
 
  ARCCORE_HOST_DEVICE SmallSpan<ElementType> operator()(Int32 i) const
  {
    ARCCORE_CHECK_AT(i, m_dim1_size);
    return SmallSpan<ElementType>(m_ptr + (m_dim2_size * i), m_dim2_size);
  }
};
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
/*!
 * \ingroup Collection
 *
 * \brief View for a 2D array whose size is an 'Int64'
 *
 * Like any view, an instance of this class is only valid as long as
 * the container it originated from does not change its number of elements.
 */
template <class T, Int64 Extent1, Int64 Extent2>
class Span2
: public Span2Impl<T, Int64, Extent1, Extent2>
{
 public:
 
  using ThatClass = Span2<T, Extent1, Extent2>;
  using BaseClass = Span2Impl<T, Int64, Extent1, Extent2>;
  using size_type = Int64;
  using value_type = typename BaseClass::value_type;
  using pointer = typename BaseClass::pointer;
  using BaseClass::operator();
  using BaseClass::operator[];
  using ElementType = typename BaseClass::ElementType;
 
 private:
 
  using BaseClass::m_dim1_size;
  using BaseClass::m_dim2_size;
  using BaseClass::m_ptr;
 
 public:
 
  //! Creates a 2D view of dimension [\a dim1_size][\a dim2_size]
  ARCCORE_HOST_DEVICE Span2(pointer ptr, Int64 dim1_size, Int64 dim2_size)
  : BaseClass(ptr, dim1_size, dim2_size)
  {}
  //! Creates an empty 2D view.
  ARCCORE_HOST_DEVICE Span2()
  : BaseClass()
  {}
  //! Copy constructor from another view
  Span2(const Array2View<value_type>& from)
  : BaseClass(from.m_ptr, from.dim1Size(), from.dim2Size())
  {}
  // Constructor from a ConstArrayView. This is only allowed
  // if T is const.
  template <typename X, typename = std::enable_if_t<std::is_same_v<X, value_type>>>
  Span2(const ConstArray2View<X>& from)
  : BaseClass(from.m_ptr, from.dim1Size(), from.dim2Size())
  {}
 
  //! Copy constructor from a 'SmallSpan'
  Span2(const SmallSpan2<T>& from)
  : BaseClass(from.m_ptr, from.dim1Size(), from.dim2Size())
  {}
 
  // For a Span<const T>, we are allowed to construct from a Span<T>
  template <typename X, typename = std::enable_if_t<std::is_same_v<X, value_type>>>
  ARCCORE_HOST_DEVICE Span2(const Span2<X>& from)
  : BaseClass(from)
  {}
 
  // For a Span<const T>, we are allowed to construct from a SmallSpan<T>
  template <typename X, typename = std::enable_if_t<std::is_same_v<X, value_type>>>
  ARCCORE_HOST_DEVICE Span2(const SmallSpan2<X>& from)
  : BaseClass(from.data(), from.dim1Size(), from.dim2Size())
  {}
 
 public:
 
  ARCCORE_HOST_DEVICE Span<ElementType> operator[](Int64 i) const
  {
    ARCCORE_CHECK_AT(i, m_dim1_size);
    return Span<ElementType>(m_ptr + (m_dim2_size * i), m_dim2_size);
  }
 
  ARCCORE_HOST_DEVICE Span<ElementType> operator()(Int64 i) const
  {
    ARCCORE_CHECK_AT(i, m_dim1_size);
    return Span<ElementType>(m_ptr + (m_dim2_size * i), m_dim2_size);
  }
};
 
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} // namespace Arcane
 
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#endif