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// Test default construction:
14//
15// constexpr mapping() noexcept;
16//
17//
18// Preconditions: layout_right::mapping<extents_type>().required_span_size() is representable as a value of type index_type ([basic.fundamental]).
19//
20// Effects: Direct-non-list-initializes extents_ with extents_type(), and for all d in the range [0, rank_),
21// direct-non-list-initializes strides_[d] with layout_right::mapping<extents_type>().stride(d).
22
23#include <cassert>
24#include <cstddef>
25#include <cstdint>
26#include <mdspan>
27
28#include "test_macros.h"
29
30template <class E>
31constexpr void test_construction() {
32 using M = std::layout_stride::mapping<E>;
33 ASSERT_NOEXCEPT(M{});
34 M m;
35 E e;
36
37 // check correct extents are returned
38 ASSERT_NOEXCEPT(m.extents());
39 assert(m.extents() == e);
40
41 // check required_span_size()
42 typename E::index_type expected_size = 1;
43 for (typename E::rank_type r = 0; r < E::rank(); r++)
44 expected_size *= e.extent(r);
45 assert(m.required_span_size() == expected_size);
46
47 // check strides: node stride function is constrained on rank>0, e.extent(r) is not
48 auto strides = m.strides();
49 ASSERT_NOEXCEPT(m.strides());
50 if constexpr (E::rank() > 0) {
51 std::layout_right::mapping<E> m_right;
52 for (typename E::rank_type r = 0; r < E::rank(); r++) {
53 assert(m.stride(r) == m_right.stride(r));
54 assert(strides[r] == m.stride(r));
55 }
56 }
57}
58
59constexpr bool test() {
60 constexpr size_t D = std::dynamic_extent;
61 test_construction<std::extents<int>>();
62 test_construction<std::extents<unsigned, D>>();
63 test_construction<std::extents<unsigned, 7>>();
64 test_construction<std::extents<unsigned, 0>>();
65 test_construction<std::extents<unsigned, 7, 8>>();
66 test_construction<std::extents<int64_t, D, 8, D, D>>();
67 return true;
68}
69
70int main(int, char**) {
71 test();
72 static_assert(test());
73 return 0;
74}
75

source code of libcxx/test/std/containers/views/mdspan/layout_stride/ctor.default.pass.cpp