libcxx/test/std/containers/views/mdspan/layout_stride/deduction.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 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
   9 // ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-ctad-maybe-unsupported
  10
  11 // <mdspan>
  12
  13 #include <array>
  14 #include <cassert>
  15 #include <cstddef>
  16 #include <cstdint>
  17 #include <mdspan>
  18 #include <span> // dynamic_extent
  19 #include <utility>
  20
  21 #include "test_macros.h"
  22
  23 // mdspan
  24
  25 // layout_stride::mapping does not have explicit deduction guides,
  26 // but implicit deduction guides for constructor taking extents and strides
  27 // should work
  28
  29 constexpr bool test() {
  30   constexpr size_t D = std::dynamic_extent;
  31
  32   ASSERT_SAME_TYPE(decltype(std::layout_stride::mapping(std::extents<int>(), std::array<unsigned, 0>())),
  33                    std::layout_stride::mapping<std::extents<int>>);
  34   ASSERT_SAME_TYPE(decltype(std::layout_stride::mapping(std::extents<int, 4>(), std::array<char, 1>{1})),
  35                    std::layout_stride::mapping<std::extents<int, 4>>);
  36   ASSERT_SAME_TYPE(decltype(std::layout_stride::mapping(std::extents<int, D>(), std::array<char, 1>{1})),
  37                    std::layout_stride::mapping<std::extents<int, D>>);
  38   ASSERT_SAME_TYPE(
  39       decltype(std::layout_stride::mapping(std::extents<unsigned, D, 3>(), std::array<std::int64_t, 2>{3, 100})),
  40       std::layout_stride::mapping<std::extents<unsigned, D, 3>>);
  41
  42   ASSERT_SAME_TYPE(decltype(std::layout_stride::mapping(std::extents<int>(), std::span<unsigned, 0>())),
  43                    std::layout_stride::mapping<std::extents<int>>);
  44   ASSERT_SAME_TYPE(decltype(std::layout_stride::mapping(std::extents<int, 4>(), std::declval<std::span<char, 1>>())),
  45                    std::layout_stride::mapping<std::extents<int, 4>>);
  46   ASSERT_SAME_TYPE(decltype(std::layout_stride::mapping(std::extents<int, D>(), std::declval<std::span<char, 1>>())),
  47                    std::layout_stride::mapping<std::extents<int, D>>);
  48   ASSERT_SAME_TYPE(
  49       decltype(std::layout_stride::mapping(std::extents<unsigned, D, 3>(), std::declval<std::span<std::int64_t, 2>>())),
  50       std::layout_stride::mapping<std::extents<unsigned, D, 3>>);
  51   return true;
  52 }
  53
  54 int main(int, char**) {
  55   test();
  56   static_assert(test());
  57   return 0;
  58 }