libcxx/test/std/containers/views/mdspan/layout_right/ctor.mapping.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(!is_convertible_v<OtherExtents, extents_type>)
  15 //     mapping(const mapping<OtherExtents>&) noexcept;
  16
  17 // Constraints: is_constructible_v<extents_type, OtherExtents> is true.
  18 //
  19 // Preconditions: other.required_span_size() is representable as a value of type index_type
  20
  21 #include <mdspan>
  22 #include <type_traits>
  23 #include <cassert>
  24 #include <limits>
  25
  26 #include "test_macros.h"
  27
  28 template <class To, class From>
  29 constexpr void test_implicit_conversion(To dest, From src) {
  30   assert(dest == src);
  31 }
  32
  33 template <bool implicit, class ToE, class FromE>
  34 constexpr void test_conversion(FromE src_exts) {
  35   using To   = std::layout_right::mapping<ToE>;
  36   using From = std::layout_right::mapping<FromE>;
  37   From src(src_exts);
  38
  39   ASSERT_NOEXCEPT(To(src));
  40   To dest(src);
  41
  42   assert(dest == src);
  43   if constexpr (implicit) {
  44     dest = src;
  45     assert(dest == src);
  46     test_implicit_conversion<To, From>(src, src);
  47   }
  48 }
  49
  50 template <class T1, class T2>
  51 constexpr void test_conversion() {
  52   constexpr size_t D = std::dynamic_extent;
  53   constexpr bool idx_convertible =
  54       static_cast<size_t>(std::numeric_limits<T1>::max()) >= static_cast<size_t>(std::numeric_limits<T2>::max());
  55
  56   // clang-format off
  57   test_conversion<idx_convertible && true,  std::extents<T1>>(std::extents<T2>());
  58   test_conversion<idx_convertible && true,  std::extents<T1, D>>(std::extents<T2, D>(5));
  59   test_conversion<idx_convertible && false, std::extents<T1, 5>>(std::extents<T2, D>(5));
  60   test_conversion<idx_convertible && true,  std::extents<T1, 5>>(std::extents<T2, 5>());
  61   test_conversion<idx_convertible && false, std::extents<T1, 5, D>>(std::extents<T2, D, D>(5, 5));
  62   test_conversion<idx_convertible && true,  std::extents<T1, D, D>>(std::extents<T2, D, D>(5, 5));
  63   test_conversion<idx_convertible && true,  std::extents<T1, D, D>>(std::extents<T2, D, 7>(5));
  64   test_conversion<idx_convertible && true,  std::extents<T1, 5, 7>>(std::extents<T2, 5, 7>());
  65   test_conversion<idx_convertible && false, std::extents<T1, 5, D, 8, D, D>>(std::extents<T2, D, D, 8, 9, 1>(5, 7));
  66   test_conversion<idx_convertible && true,  std::extents<T1, D, D, D, D, D>>(
  67                                             std::extents<T2, D, D, D, D, D>(5, 7, 8, 9, 1));
  68   test_conversion<idx_convertible && true,  std::extents<T1, D, D, 8, 9, D>>(std::extents<T2, D, 7, 8, 9, 1>(5));
  69   test_conversion<idx_convertible && true,  std::extents<T1, 5, 7, 8, 9, 1>>(std::extents<T2, 5, 7, 8, 9, 1>());
  70   // clang-format on
  71 }
  72
  73 template <class IdxT, size_t... Extents>
  74 using mapping_t = std::layout_right::mapping<std::extents<IdxT, Extents...>>;
  75
  76 constexpr void test_no_implicit_conversion() {
  77   constexpr size_t D = std::dynamic_extent;
  78
  79   // Sanity check that one static to dynamic conversion works
  80   static_assert(std::is_constructible_v<mapping_t<int, D>, mapping_t<int, 5>>);
  81   static_assert(std::is_convertible_v<mapping_t<int, 5>, mapping_t<int, D>>);
  82
  83   // Check that dynamic to static conversion only works explicitly
  84   static_assert(std::is_constructible_v<mapping_t<int, 5>, mapping_t<int, D>>);
  85   static_assert(!std::is_convertible_v<mapping_t<int, D>, mapping_t<int, 5>>);
  86
  87   // Sanity check that one static to dynamic conversion works
  88   static_assert(std::is_constructible_v<mapping_t<int, D, 7>, mapping_t<int, 5, 7>>);
  89   static_assert(std::is_convertible_v<mapping_t<int, 5, 7>, mapping_t<int, D, 7>>);
  90
  91   // Check that dynamic to static conversion only works explicitly
  92   static_assert(std::is_constructible_v<mapping_t<int, 5, 7>, mapping_t<int, D, 7>>);
  93   static_assert(!std::is_convertible_v<mapping_t<int, D, 7>, mapping_t<int, 5, 7>>);
  94
  95   // Sanity check that smaller index_type to larger index_type conversion works
  96   static_assert(std::is_constructible_v<mapping_t<size_t, 5>, mapping_t<int, 5>>);
  97   static_assert(std::is_convertible_v<mapping_t<int, 5>, mapping_t<size_t, 5>>);
  98
  99   // Check that larger index_type to smaller index_type conversion works explicitly only
 100   static_assert(std::is_constructible_v<mapping_t<int, 5>, mapping_t<size_t, 5>>);
 101   static_assert(!std::is_convertible_v<mapping_t<size_t, 5>, mapping_t<int, 5>>);
 102 }
 103
 104 constexpr void test_rank_mismatch() {
 105   constexpr size_t D = std::dynamic_extent;
 106
 107   static_assert(!std::is_constructible_v<mapping_t<int, D>, mapping_t<int>>);
 108   static_assert(!std::is_constructible_v<mapping_t<int>, mapping_t<int, D, D>>);
 109   static_assert(!std::is_constructible_v<mapping_t<int, D>, mapping_t<int, D, D>>);
 110   static_assert(!std::is_constructible_v<mapping_t<int, D, D, D>, mapping_t<int, D, D>>);
 111 }
 112
 113 constexpr void test_static_extent_mismatch() {
 114   constexpr size_t D = std::dynamic_extent;
 115
 116   static_assert(!std::is_constructible_v<mapping_t<int, D, 5>, mapping_t<int, D, 4>>);
 117   static_assert(!std::is_constructible_v<mapping_t<int, 5>, mapping_t<int, 4>>);
 118   static_assert(!std::is_constructible_v<mapping_t<int, 5, D>, mapping_t<int, 4, D>>);
 119 }
 120
 121 constexpr bool test() {
 122   test_conversion<int, int>();
 123   test_conversion<int, size_t>();
 124   test_conversion<size_t, int>();
 125   test_conversion<size_t, long>();
 126   test_no_implicit_conversion();
 127   test_rank_mismatch();
 128   test_static_extent_mismatch();
 129   return true;
 130 }
 131
 132 int main(int, char**) {
 133   test();
 134   static_assert(test());
 135   return 0;
 136 }