include/mdspan

// -*-C++ - *-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===---------------------------------------------------------------------===//

/*
    extents synopsis

namespace std {
  template<class _IndexType, size_t... _Extents>
  class extents {
  public:
    using index_type = _IndexType;
    using size_type = make_unsigned_t<index_type>;
    using rank_type = size_t;

    // [mdspan.extents.obs], observers of the multidimensional index space
    static constexpr rank_type rank() noexcept { return sizeof...(_Extents); }
    static constexpr rank_type rank_dynamic() noexcept { return dynamic-index(rank()); }
    static constexpr size_t static_extent(rank_type) noexcept;
    constexpr index_type extent(rank_type) const noexcept;

    // [mdspan.extents.cons], constructors
    constexpr extents() noexcept = default;

    template<class _OtherIndexType, size_t... _OtherExtents>
      constexpr explicit(see below)
        extents(const extents<_OtherIndexType, _OtherExtents...>&) noexcept;
    template<class... _OtherIndexTypes>
      constexpr explicit extents(_OtherIndexTypes...) noexcept;
    template<class _OtherIndexType, size_t N>
      constexpr explicit(N != rank_dynamic())
        extents(span<_OtherIndexType, N>) noexcept;
    template<class _OtherIndexType, size_t N>
      constexpr explicit(N != rank_dynamic())
        extents(const array<_OtherIndexType, N>&) noexcept;

    // [mdspan.extents.cmp], comparison operators
    template<class _OtherIndexType, size_t... _OtherExtents>
      friend constexpr bool operator==(const extents&,
                                       const extents<_OtherIndexType, _OtherExtents...>&) noexcept;

  private:
    // libcxx note: we do not use an array here, but we need to preserve the as-if behavior
    // for example the default constructor must zero initialize dynamic extents
    array<index_type, rank_dynamic()> dynamic-extents{};                // exposition only
  };

  template<class... Integrals>
    explicit extents(Integrals...)
      -> see below;
}
*/

#ifndef _LIBCPP_MDSPAN
#define _LIBCPP_MDSPAN

#include <__config>
#include <__mdspan/extents.h>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

#endif // _LIBCPP_MDSPAN