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, c++23
10
11// <mdspan>
12//
13// template<class OtherElementType, size_t OtherByteAlignment>
14// constexpr aligned_accessor(aligned_accessor<OtherElementType, OtherByteAlignment>) noexcept {}
15//
16// Constraints:
17// - is_convertible_v<OtherElementType(*)[], element_type(*)[]> is true.
18// - OtherByteAlignment >= byte_alignment is true.
19
20#include <mdspan>
21#include <cassert>
22#include <cstddef>
23#include <type_traits>
24
25#include "test_macros.h"
26
27#include "../MinimalElementType.h"
28
29struct Base {};
30struct Derived : public Base {};
31
32template <class FromT, std::size_t FromN, class ToT, std::size_t ToN>
33constexpr void test_conversion() {
34 std::aligned_accessor<FromT, FromN> acc_from;
35 ASSERT_NOEXCEPT(std::aligned_accessor<ToT, ToN>(acc_from));
36 [[maybe_unused]] std::aligned_accessor<ToT, ToN> acc_to(acc_from);
37}
38
39template <class From, class To>
40constexpr void test_it() {
41 constexpr std::size_t N = alignof(From);
42 static_assert(N == alignof(To));
43
44 test_conversion<From, N, To, N>();
45 test_conversion<From, 2 * N, To, N>();
46 test_conversion<From, 4 * N, To, N>();
47 test_conversion<From, 8 * N, To, N>();
48 test_conversion<From, 16 * N, To, N>();
49 test_conversion<From, 32 * N, To, N>();
50
51 test_conversion<From, 2 * N, To, 2 * N>();
52 test_conversion<From, 4 * N, To, 2 * N>();
53 test_conversion<From, 8 * N, To, 2 * N>();
54 test_conversion<From, 16 * N, To, 2 * N>();
55 test_conversion<From, 32 * N, To, 2 * N>();
56
57 test_conversion<From, 4 * N, To, 4 * N>();
58 test_conversion<From, 8 * N, To, 4 * N>();
59 test_conversion<From, 16 * N, To, 4 * N>();
60 test_conversion<From, 32 * N, To, 4 * N>();
61
62 test_conversion<From, 8 * N, To, 8 * N>();
63 test_conversion<From, 16 * N, To, 8 * N>();
64 test_conversion<From, 32 * N, To, 8 * N>();
65
66 test_conversion<From, 16 * N, To, 16 * N>();
67 test_conversion<From, 32 * N, To, 16 * N>();
68
69 test_conversion<From, 32 * N, To, 32 * N>();
70}
71
72constexpr bool test() {
73 test_it<int, int>();
74 test_it<int, const int>();
75 test_it<const int, const int>();
76 test_it<MinimalElementType, MinimalElementType>();
77 test_it<MinimalElementType, const MinimalElementType>();
78 test_it<const MinimalElementType, const MinimalElementType>();
79
80 // char is convertible to int, but accessors are not
81 static_assert(!std::is_constructible_v<std::aligned_accessor<int, 4>, std::aligned_accessor<char, 4>>);
82 // don't allow conversion from const elements to non-const
83 static_assert(!std::is_constructible_v<std::aligned_accessor<int, 4>, std::aligned_accessor<const int, 4>>);
84 // don't allow conversion from less to more alignment
85 static_assert(!std::is_constructible_v<std::aligned_accessor<int, 8>, std::aligned_accessor<int, 4>>);
86 static_assert(!std::is_constructible_v<std::aligned_accessor<const int, 8>, std::aligned_accessor<const int, 4>>);
87 // MinimalElementType is constructible from int, but accessors should not be convertible
88 static_assert(!std::is_constructible_v<std::aligned_accessor<MinimalElementType, 8>, std::aligned_accessor<int, 8>>);
89 // don't allow conversion from const elements to non-const
90 static_assert(!std::is_constructible_v<std::aligned_accessor<MinimalElementType, 16>,
91 std::aligned_accessor<const MinimalElementType, 16>>);
92 // don't allow conversion from Base to Derived
93 static_assert(!std::is_constructible_v<std::aligned_accessor<Derived, 1>, std::aligned_accessor<Base, 1>>);
94 // don't allow conversion from Derived to Base
95 static_assert(!std::is_constructible_v<std::aligned_accessor<Base, 1>, std::aligned_accessor<Derived, 1>>);
96
97 return true;
98}
99
100int main(int, char**) {
101 test();
102 static_assert(test());
103 return 0;
104}
105

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