libcxx/test/std/containers/views/mdspan/layout_right/ctor.layout_stride.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 // template<class OtherExtents>
  14 //   constexpr explicit(extents_type::rank() > 0)
  15 //     mapping(const layout_stride::mapping<OtherExtents>& other);
  16 //
  17 // Constraints: is_constructible_v<extents_type, OtherExtents> is true.
  18 //
  19 // Preconditions:
  20 //   - If extents_type::rank() > 0 is true, then for all r in the range [0, extents_type::rank()),
  21 //     other.stride(r) equals other.extents().fwd-prod-of-extents(r), and
  22 //   - other.required_span_size() is representable as a value of type index_type ([basic.fundamental]).
  23 //
  24 // Effects: Direct-non-list-initializes extents_ with other.extents().
  25
  26 #include <array>
  27 #include <cassert>
  28 #include <cstddef>
  29 #include <mdspan>
  30 #include <span> // dynamic_extent
  31 #include <type_traits>
  32
  33 #include "test_macros.h"
  34
  35 template <bool implicit, class ToE, class FromE>
  36 constexpr void test_conversion(FromE src_exts) {
  37   using To   = std::layout_left::mapping<ToE>;
  38   using From = std::layout_stride::mapping<FromE>;
  39   std::array<typename FromE::index_type, FromE::rank()> strides;
  40   if constexpr (FromE::rank() > 0) {
  41     strides[0] = 1;
  42     for (size_t r = 1; r < FromE::rank(); r++)
  43       strides[r] = src_exts.extent(r - 1) * strides[r - 1];
  44   }
  45   From src(src_exts, strides);
  46
  47   ASSERT_NOEXCEPT(To(src));
  48   To dest(src);
  49   assert(dest == src);
  50
  51   if constexpr (implicit) {
  52     To dest_implicit = src;
  53     assert(dest_implicit == src);
  54   } else {
  55     assert((!std::is_convertible_v<From, To>));
  56   }
  57 }
  58
  59 template <class T1, class T2>
  60 constexpr void test_conversion() {
  61   constexpr size_t D = std::dynamic_extent;
  62
  63   // clang-format off
  64   test_conversion<true,  std::extents<T1>>(std::extents<T2>());
  65   test_conversion<false, std::extents<T1, D>>(std::extents<T2, D>(5));
  66   test_conversion<false, std::extents<T1, 5>>(std::extents<T2, D>(5));
  67   test_conversion<false, std::extents<T1, 5>>(std::extents<T2, 5>());
  68   test_conversion<false, std::extents<T1, 5, D>>(std::extents<T2, D, D>(5, 5));
  69   test_conversion<false, std::extents<T1, D, D>>(std::extents<T2, D, D>(5, 5));
  70   test_conversion<false, std::extents<T1, D, D>>(std::extents<T2, D, 7>(5));
  71   test_conversion<false, std::extents<T1, 5, 7>>(std::extents<T2, 5, 7>());
  72   test_conversion<false, std::extents<T1, 5, D, 8, D, D>>(std::extents<T2, D, D, 8, 9, 1>(5, 7));
  73   test_conversion<false, std::extents<T1, D, D, D, D, D>>(
  74                          std::extents<T2, D, D, D, D, D>(5, 7, 8, 9, 1));
  75   test_conversion<false, std::extents<T1, D, D, 8, 9, D>>(std::extents<T2, D, 7, 8, 9, 1>(5));
  76   test_conversion<false, std::extents<T1, 5, 7, 8, 9, 1>>(std::extents<T2, 5, 7, 8, 9, 1>());
  77   // clang-format on
  78 }
  79
  80 template <class IdxT, size_t... Extents>
  81 using lr_mapping_t = std::layout_right::mapping<std::extents<IdxT, Extents...>>;
  82 template <class IdxT, size_t... Extents>
  83 using ls_mapping_t = std::layout_stride::mapping<std::extents<IdxT, Extents...>>;
  84
  85 constexpr void test_rank_mismatch() {
  86   constexpr size_t D = std::dynamic_extent;
  87
  88   static_assert(!std::is_constructible_v<lr_mapping_t<int, D>, ls_mapping_t<int>>);
  89   static_assert(!std::is_constructible_v<lr_mapping_t<int>, ls_mapping_t<int, D, D>>);
  90   static_assert(!std::is_constructible_v<lr_mapping_t<int, D>, ls_mapping_t<int, D, D>>);
  91   static_assert(!std::is_constructible_v<lr_mapping_t<int, D, D, D>, ls_mapping_t<int, D, D>>);
  92 }
  93
  94 constexpr void test_static_extent_mismatch() {
  95   constexpr size_t D = std::dynamic_extent;
  96
  97   static_assert(!std::is_constructible_v<lr_mapping_t<int, D, 5>, ls_mapping_t<int, D, 4>>);
  98   static_assert(!std::is_constructible_v<lr_mapping_t<int, 5>, ls_mapping_t<int, 4>>);
  99   static_assert(!std::is_constructible_v<lr_mapping_t<int, 5, D>, ls_mapping_t<int, 4, D>>);
 100 }
 101
 102 constexpr bool test() {
 103   test_conversion<int, int>();
 104   test_conversion<int, size_t>();
 105   test_conversion<size_t, int>();
 106   test_conversion<size_t, long>();
 107   test_rank_mismatch();
 108   test_static_extent_mismatch();
 109   return true;
 110 }
 111
 112 int main(int, char**) {
 113   test();
 114   static_assert(test());
 115   return 0;
 116 }