xref: /llvm-project/libcxx/test/std/containers/views/mdspan/layout_stride/deduction.pass.cpp (revision e99c4906e44ae3f921fa05356909d006cda8d954)
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 }
59