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 OtherIndexType>
14// constexpr mapping(const extents_type& e, span<OtherIndexType, rank_> s) noexcept;
15//
16// Constraints:
17// - is_convertible_v<const OtherIndexType&, index_type> is true, and
18// - is_nothrow_constructible_v<index_type, const OtherIndexType&> is true.
19//
20// Preconditions:
21// - s[i] > 0 is true for all i in the range [0, rank_).
22// - REQUIRED-SPAN-SIZE(e, s) is representable as a value of type index_type ([basic.fundamental]).
23// - If rank_ is greater than 0, then there exists a permutation P of the integers in the range [0, rank_),
24// such that s[pi] >= s[pi_1] * e.extent(pi_1) is true for all i in the range [1, rank_), where pi is the ith element of P.
25// Note 1: For layout_stride, this condition is necessary and sufficient for is_unique() to be true.
26//
27// Effects: Direct-non-list-initializes extents_ with e, and for all d in the range [0, rank_),
28// direct-non-list-initializes strides_[d] with as_const(s[d]).
29
30#include <mdspan>
31#include <cassert>
32#include <cstdint>
33
34#include "test_macros.h"
35#include "../ConvertibleToIntegral.h"
36
37template <class E, class S>
38constexpr void test_construction(E e, S s) {
39 using M = std::layout_stride::mapping<E>;
40 ASSERT_NOEXCEPT(M{e, s});
41 M m(e, s);
42
43 // check correct extents are returned
44 ASSERT_NOEXCEPT(m.extents());
45 assert(m.extents() == e);
46
47 // check required_span_size()
48 typename E::index_type expected_size = 1;
49 for (typename E::rank_type r = 0; r < E::rank(); r++) {
50 if (e.extent(r) == 0) {
51 expected_size = 0;
52 break;
53 }
54 expected_size += (e.extent(r) - 1) * static_cast<typename E::index_type>(s[r]);
55 }
56 assert(m.required_span_size() == expected_size);
57
58 // check strides: node stride function is constrained on rank>0, e.extent(r) is not
59 auto strides = m.strides();
60 ASSERT_NOEXCEPT(m.strides());
61 if constexpr (E::rank() > 0) {
62 for (typename E::rank_type r = 0; r < E::rank(); r++) {
63 assert(m.stride(r) == static_cast<typename E::index_type>(s[r]));
64 assert(strides[r] == m.stride(r));
65 }
66 }
67}
68
69constexpr bool test() {
70 constexpr size_t D = std::dynamic_extent;
71 {
72 std::array<int, 0> s{};
73 test_construction(std::extents<int>(), std::span(s));
74 }
75 {
76 std::array<int, 1> s{1};
77 test_construction(std::extents<unsigned, D>(7), std::span(s));
78 }
79 {
80 std::array<int, 1> s{1};
81 test_construction(std::extents<unsigned, D>(0), std::span(s));
82 }
83 {
84 std::array<int, 1> s{2};
85 test_construction(std::extents<unsigned, 7>(), std::span(s));
86 }
87 {
88 std::array<IntType, 1> s{1};
89 test_construction(std::extents<int, D>(7), std::span(s));
90 }
91 {
92 std::array<int, 2> s{3, 30};
93 test_construction(std::extents<unsigned, 7, 8>(), std::span(s));
94 }
95 {
96 std::array<int, 4> s{20, 2, 200, 2000};
97 test_construction(std::extents<int64_t, D, 8, D, D>(7, 9, 10), std::span(s));
98 }
99 {
100 std::array<int, 4> s{20, 2, 200, 2000};
101 test_construction(std::extents<int64_t, D, 8, D, D>(7, 0, 10), std::span(s));
102 test_construction(std::extents<int64_t, D, 8, D, D>(0, 9, 10), std::span(s));
103 test_construction(std::extents<int64_t, D, 8, D, D>(0, 8, 0), std::span(s));
104 }
105 {
106 std::array<int, 4> s{200, 20, 20, 2000};
107 test_construction(std::extents<int64_t, D, D, D, D>(7, 0, 8, 9), std::span(s));
108 test_construction(std::extents<int64_t, D, D, D, D>(7, 8, 0, 9), std::span(s));
109 test_construction(std::extents<int64_t, D, D, D, D>(7, 1, 8, 9), std::span(s));
110 test_construction(std::extents<int64_t, D, D, D, D>(7, 8, 1, 9), std::span(s));
111 test_construction(std::extents<int64_t, D, D, D, D>(7, 1, 1, 9), std::span(s));
112 test_construction(std::extents<int64_t, D, D, D, D>(7, 0, 0, 9), std::span(s));
113 test_construction(std::extents<int64_t, D, D, D, D>(7, 1, 1, 9), std::span(s));
114 test_construction(std::extents<int64_t, D, D, D, D>(7, 1, 0, 9), std::span(s));
115 test_construction(std::extents<int64_t, D, D, D, D>(7, 0, 1, 9), std::span(s));
116 }
117
118 {
119 using mapping_t = std::layout_stride::mapping<std::dextents<unsigned, 2>>;
120 // wrong strides size
121 static_assert(!std::is_constructible_v<mapping_t, std::dextents<int, 2>, std::span<int, 3>>);
122 static_assert(!std::is_constructible_v<mapping_t, std::dextents<int, 2>, std::span<int, 1>>);
123 // wrong extents rank
124 static_assert(!std::is_constructible_v<mapping_t, std::dextents<int, 3>, std::span<int, 2>>);
125 // none-convertible strides
126 static_assert(!std::is_constructible_v<mapping_t, std::dextents<int, 2>, std::span<IntType, 2>>);
127 }
128 {
129 // not no-throw constructible index_type from stride
130 using mapping_t = std::layout_stride::mapping<std::dextents<unsigned char, 2>>;
131 static_assert(std::is_convertible_v<IntType, unsigned char>);
132 static_assert(!std::is_constructible_v<mapping_t, std::dextents<int, 2>, std::span<IntType, 2>>);
133 }
134 return true;
135}
136
137int main(int, char**) {
138 test();
139 static_assert(test());
140 return 0;
141}
142

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