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
10// <mdspan>
11
12// template<class OtherIndexType, size_t... OtherExtents>
13// constexpr explicit(see below) extents(const extents<OtherIndexType, OtherExtents...>&) noexcept;
14//
15// Constraints:
16// * sizeof...(OtherExtents) == rank() is true.
17// * ((OtherExtents == dynamic_extent || Extents == dynamic_extent ||
18// OtherExtents == Extents) && ...) is true.
19//
20// Preconditions:
21// * other.extent(r) equals Er for each r for which Er is a static extent, and
22// * either
23// - sizeof...(OtherExtents) is zero, or
24// - other.extent(r) is representable as a value of type index_type for
25// every rank index r of other.
26//
27// Remarks: The expression inside explicit is equivalent to:
28// (((Extents != dynamic_extent) && (OtherExtents == dynamic_extent)) || ... ) ||
29// (numeric_limits<index_type>::max() < numeric_limits<OtherIndexType>::max())
30
31#include <mdspan>
32#include <type_traits>
33#include <concepts>
34#include <cassert>
35#include <limits>
36
37#include "test_macros.h"
38
39template <class To, class From>
40constexpr void test_implicit_conversion(To dest, From src) {
41 assert(dest == src);
42}
43
44template <bool implicit, class To, class From>
45constexpr void test_conversion(From src) {
46 To dest(src);
47 assert(dest == src);
48 if constexpr (implicit) {
49 dest = src;
50 assert(dest == src);
51 test_implicit_conversion<To, From>(src, src);
52 }
53}
54
55template <class T1, class T2>
56constexpr void test_conversion() {
57 constexpr size_t D = std::dynamic_extent;
58 constexpr bool idx_convertible =
59 static_cast<size_t>(std::numeric_limits<T1>::max()) >= static_cast<size_t>(std::numeric_limits<T2>::max());
60
61 // clang-format off
62 test_conversion<idx_convertible && true, std::extents<T1>>(std::extents<T2>());
63 test_conversion<idx_convertible && true, std::extents<T1, D>>(std::extents<T2, D>(5));
64 test_conversion<idx_convertible && false, std::extents<T1, 5>>(std::extents<T2, D>(5));
65 test_conversion<idx_convertible && true, std::extents<T1, 5>>(std::extents<T2, 5>());
66 test_conversion<idx_convertible && false, std::extents<T1, 5, D>>(std::extents<T2, D, D>(5, 5));
67 test_conversion<idx_convertible && true, std::extents<T1, D, D>>(std::extents<T2, D, D>(5, 5));
68 test_conversion<idx_convertible && true, std::extents<T1, D, D>>(std::extents<T2, D, 7>(5));
69 test_conversion<idx_convertible && true, std::extents<T1, 5, 7>>(std::extents<T2, 5, 7>());
70 test_conversion<idx_convertible && false, std::extents<T1, 5, D, 8, D, D>>(std::extents<T2, D, D, 8, 9, 1>(5, 7));
71 test_conversion<idx_convertible && true, std::extents<T1, D, D, D, D, D>>(
72 std::extents<T2, D, D, D, D, D>(5, 7, 8, 9, 1));
73 test_conversion<idx_convertible && true, std::extents<T1, D, D, 8, 9, D>>(std::extents<T2, D, 7, 8, 9, 1>(5));
74 test_conversion<idx_convertible && true, std::extents<T1, 5, 7, 8, 9, 1>>(std::extents<T2, 5, 7, 8, 9, 1>());
75 // clang-format on
76}
77
78constexpr void test_no_implicit_conversion() {
79 constexpr size_t D = std::dynamic_extent;
80 // Sanity check that one static to dynamic conversion works
81 static_assert(std::is_constructible_v<std::extents<int, D>, std::extents<int, 5>>, "");
82 static_assert(std::is_convertible_v<std::extents<int, 5>, std::extents<int, D>>, "");
83
84 // Check that dynamic to static conversion only works explicitly only
85 static_assert(std::is_constructible_v<std::extents<int, 5>, std::extents<int, D>>, "");
86 static_assert(!std::is_convertible_v<std::extents<int, D>, std::extents<int, 5>>, "");
87
88 // Sanity check that one static to dynamic conversion works
89 static_assert(std::is_constructible_v<std::extents<int, D, 7>, std::extents<int, 5, 7>>, "");
90 static_assert(std::is_convertible_v<std::extents<int, 5, 7>, std::extents<int, D, 7>>, "");
91
92 // Check that dynamic to static conversion only works explicitly only
93 static_assert(std::is_constructible_v<std::extents<int, 5, 7>, std::extents<int, D, 7>>, "");
94 static_assert(!std::is_convertible_v<std::extents<int, D, 7>, std::extents<int, 5, 7>>, "");
95
96 // Sanity check that smaller index_type to larger index_type conversion works
97 static_assert(std::is_constructible_v<std::extents<size_t, 5>, std::extents<int, 5>>, "");
98 static_assert(std::is_convertible_v<std::extents<int, 5>, std::extents<size_t, 5>>, "");
99
100 // Check that larger index_type to smaller index_type conversion works explicitly only
101 static_assert(std::is_constructible_v<std::extents<int, 5>, std::extents<size_t, 5>>, "");
102 static_assert(!std::is_convertible_v<std::extents<size_t, 5>, std::extents<int, 5>>, "");
103}
104
105constexpr void test_rank_mismatch() {
106 constexpr size_t D = std::dynamic_extent;
107
108 static_assert(!std::is_constructible_v<std::extents<int, D>, std::extents<int>>, "");
109 static_assert(!std::is_constructible_v<std::extents<int>, std::extents<int, D, D>>, "");
110 static_assert(!std::is_constructible_v<std::extents<int, D>, std::extents<int, D, D>>, "");
111 static_assert(!std::is_constructible_v<std::extents<int, D, D, D>, std::extents<int, D, D>>, "");
112}
113
114constexpr void test_static_extent_mismatch() {
115 constexpr size_t D = std::dynamic_extent;
116
117 static_assert(!std::is_constructible_v<std::extents<int, D, 5>, std::extents<int, D, 4>>, "");
118 static_assert(!std::is_constructible_v<std::extents<int, 5>, std::extents<int, 4>>, "");
119 static_assert(!std::is_constructible_v<std::extents<int, 5, D>, std::extents<int, 4, D>>, "");
120}
121
122constexpr bool test() {
123 test_conversion<int, int>();
124 test_conversion<int, size_t>();
125 test_conversion<size_t, int>();
126 test_conversion<size_t, long>();
127 test_no_implicit_conversion();
128 test_rank_mismatch();
129 test_static_extent_mismatch();
130 return true;
131}
132
133int main(int, char**) {
134 test();
135 static_assert(test());
136
137 return 0;
138}
139

source code of libcxx/test/std/containers/views/mdspan/extents/conversion.pass.cpp