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 <cassert>
  22 #include <cstddef>
  23 #include <limits>
  24 #include <mdspan>
  25 #include <span> // dynamic_extent
  26 #include <type_traits>
  27
  28 #include "test_macros.h"
  29
  30 template <class To, class From>
  31 constexpr void test_implicit_conversion(To dest, From src) {
  32   assert(dest == src);
  33 }
  34
  35 template <bool implicit, class ToE, class FromE>
  36 constexpr void test_conversion(FromE src_exts) {
  37   using To   = std::layout_right::mapping<ToE>;
  38   using From = std::layout_right::mapping<FromE>;
  39   From src(src_exts);
  40
  41   ASSERT_NOEXCEPT(To(src));
  42   To dest(src);
  43
  44   assert(dest == src);
  45   if constexpr (implicit) {
  46     dest = src;
  47     assert(dest == src);
  48     test_implicit_conversion<To, From>(src, src);
  49   }
  50 }
  51
  52 template <class T1, class T2>
  53 constexpr void test_conversion() {
  54   constexpr size_t D = std::dynamic_extent;
  55   constexpr bool idx_convertible =
  56       static_cast<size_t>(std::numeric_limits<T1>::max()) >= static_cast<size_t>(std::numeric_limits<T2>::max());
  57
  58   // clang-format off
  59   test_conversion<idx_convertible && true,  std::extents<T1>>(std::extents<T2>());
  60   test_conversion<idx_convertible && true,  std::extents<T1, D>>(std::extents<T2, D>(5));
  61   test_conversion<idx_convertible && false, std::extents<T1, 5>>(std::extents<T2, D>(5));
  62   test_conversion<idx_convertible && true,  std::extents<T1, 5>>(std::extents<T2, 5>());
  63   test_conversion<idx_convertible && false, std::extents<T1, 5, D>>(std::extents<T2, D, D>(5, 5));
  64   test_conversion<idx_convertible && true,  std::extents<T1, D, D>>(std::extents<T2, D, D>(5, 5));
  65   test_conversion<idx_convertible && true,  std::extents<T1, D, D>>(std::extents<T2, D, 7>(5));
  66   test_conversion<idx_convertible && true,  std::extents<T1, 5, 7>>(std::extents<T2, 5, 7>());
  67   test_conversion<idx_convertible && false, std::extents<T1, 5, D, 8, D, D>>(std::extents<T2, D, D, 8, 9, 1>(5, 7));
  68   test_conversion<idx_convertible && true,  std::extents<T1, D, D, D, D, D>>(
  69                                             std::extents<T2, D, D, D, D, D>(5, 7, 8, 9, 1));
  70   test_conversion<idx_convertible && true,  std::extents<T1, D, D, 8, 9, D>>(std::extents<T2, D, 7, 8, 9, 1>(5));
  71   test_conversion<idx_convertible && true,  std::extents<T1, 5, 7, 8, 9, 1>>(std::extents<T2, 5, 7, 8, 9, 1>());
  72   // clang-format on
  73 }
  74
  75 template <class IdxT, size_t... Extents>
  76 using mapping_t = std::layout_right::mapping<std::extents<IdxT, Extents...>>;
  77
  78 constexpr void test_no_implicit_conversion() {
  79   constexpr size_t D = std::dynamic_extent;
  80
  81   // Sanity check that one static to dynamic conversion works
  82   static_assert(std::is_constructible_v<mapping_t<int, D>, mapping_t<int, 5>>);
  83   static_assert(std::is_convertible_v<mapping_t<int, 5>, mapping_t<int, D>>);
  84
  85   // Check that dynamic to static conversion only works explicitly
  86   static_assert(std::is_constructible_v<mapping_t<int, 5>, mapping_t<int, D>>);
  87   static_assert(!std::is_convertible_v<mapping_t<int, D>, mapping_t<int, 5>>);
  88
  89   // Sanity check that one static to dynamic conversion works
  90   static_assert(std::is_constructible_v<mapping_t<int, D, 7>, mapping_t<int, 5, 7>>);
  91   static_assert(std::is_convertible_v<mapping_t<int, 5, 7>, mapping_t<int, D, 7>>);
  92
  93   // Check that dynamic to static conversion only works explicitly
  94   static_assert(std::is_constructible_v<mapping_t<int, 5, 7>, mapping_t<int, D, 7>>);
  95   static_assert(!std::is_convertible_v<mapping_t<int, D, 7>, mapping_t<int, 5, 7>>);
  96
  97   // Sanity check that smaller index_type to larger index_type conversion works
  98   static_assert(std::is_constructible_v<mapping_t<size_t, 5>, mapping_t<int, 5>>);
  99   static_assert(std::is_convertible_v<mapping_t<int, 5>, mapping_t<size_t, 5>>);
 100
 101   // Check that larger index_type to smaller index_type conversion works explicitly only
 102   static_assert(std::is_constructible_v<mapping_t<int, 5>, mapping_t<size_t, 5>>);
 103   static_assert(!std::is_convertible_v<mapping_t<size_t, 5>, mapping_t<int, 5>>);
 104 }
 105
 106 constexpr void test_rank_mismatch() {
 107   constexpr size_t D = std::dynamic_extent;
 108
 109   static_assert(!std::is_constructible_v<mapping_t<int, D>, mapping_t<int>>);
 110   static_assert(!std::is_constructible_v<mapping_t<int>, mapping_t<int, D, D>>);
 111   static_assert(!std::is_constructible_v<mapping_t<int, D>, mapping_t<int, D, D>>);
 112   static_assert(!std::is_constructible_v<mapping_t<int, D, D, D>, mapping_t<int, D, D>>);
 113 }
 114
 115 constexpr void test_static_extent_mismatch() {
 116   constexpr size_t D = std::dynamic_extent;
 117
 118   static_assert(!std::is_constructible_v<mapping_t<int, D, 5>, mapping_t<int, D, 4>>);
 119   static_assert(!std::is_constructible_v<mapping_t<int, 5>, mapping_t<int, 4>>);
 120   static_assert(!std::is_constructible_v<mapping_t<int, 5, D>, mapping_t<int, 4, D>>);
 121 }
 122
 123 constexpr bool test() {
 124   test_conversion<int, int>();
 125   test_conversion<int, size_t>();
 126   test_conversion<size_t, int>();
 127   test_conversion<size_t, long>();
 128   test_no_implicit_conversion();
 129   test_rank_mismatch();
 130   test_static_extent_mismatch();
 131   return true;
 132 }
 133
 134 int main(int, char**) {
 135   test();
 136   static_assert(test());
 137   return 0;
 138 }