libcxx/test/std/containers/views/mdspan/layout_right/ctor.extents.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
  10
  11 // <mdspan>
  12
  13 // constexpr mapping(const extents_type&) noexcept;
  14 //
  15 // Preconditions: The size of the multidimensional index space e is representable
  16 //                as a value of type index_type ([basic.fundamental]).
  17 //
  18 // Effects: Direct-non-list-initializes extents_ with e.
  19
  20 #include <mdspan>
  21 #include <cassert>
  22 #include <cstdint>
  23
  24 #include "test_macros.h"
  25
  26 template <class E>
  27 constexpr void test_construction(E e) {
  28   using M = std::layout_right::mapping<E>;
  29   ASSERT_NOEXCEPT(M{e});
  30   M m(e);
  31
  32   // check correct extents are returned
  33   ASSERT_NOEXCEPT(m.extents());
  34   assert(m.extents() == e);
  35
  36   // check required_span_size()
  37   typename E::index_type expected_size = 1;
  38   for (typename E::rank_type r = 0; r < E::rank(); r++)
  39     expected_size *= e.extent(r);
  40   assert(m.required_span_size() == expected_size);
  41 }
  42
  43 constexpr bool test() {
  44   constexpr size_t D = std::dynamic_extent;
  45   test_construction(std::extents<int>());
  46   test_construction(std::extents<unsigned, D>(7));
  47   test_construction(std::extents<unsigned, 7>());
  48   test_construction(std::extents<unsigned, 7, 8>());
  49   test_construction(std::extents<int64_t, D, 8, D, D>(7, 9, 10));
  50   return true;
  51 }
  52
  53 int main(int, char**) {
  54   test();
  55   static_assert(test());
  56   return 0;
  57 }