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// Test construction from array:
13//
14// template<class OtherIndexType, size_t N>
15// constexpr explicit(N != rank_dynamic()) extents(const array<OtherIndexType, N>& exts) noexcept;
16//
17// Constraints:
18// * is_convertible_v<const OtherIndexType&, index_type> is true,
19// * is_nothrow_constructible_v<index_type, const OtherIndexType&> is true, and
20// * N == rank_dynamic() || N == rank() is true.
21//
22// Preconditions:
23// * If N != rank_dynamic() is true, exts[r] equals Er for each r for which
24// Er is a static extent, and
25// * either
26// - N is zero, or
27// - exts[r] is nonnegative and is representable as a value of type index_type
28// for every rank index r.
29//
30
31#include <mdspan>
32#include <cassert>
33#include <array>
34#include <type_traits>
35
36#include "../ConvertibleToIntegral.h"
37#include "CtorTestCombinations.h"
38#include "test_macros.h"
39
40struct ArrayCtorTest {
41 template <class E, class T, size_t N, class Extents, size_t... Indices>
42 static constexpr void test_construction(std::array<T, N> all_ext, Extents ext, std::index_sequence<Indices...>) {
43 ASSERT_NOEXCEPT(E(ext));
44 if constexpr (N == E::rank_dynamic()) {
45 test_implicit_construction_call<E>(ext, all_ext);
46 }
47 test_runtime_observers(E(ext), all_ext);
48 }
49};
50
51template <class E>
52struct implicit_construction {
53 bool value;
54 implicit_construction(E) : value(true) {}
55 template <class T>
56 implicit_construction(T) : value(false) {}
57};
58
59int main(int, char**) {
60 test_index_type_combo<ArrayCtorTest>();
61 static_assert(test_index_type_combo<ArrayCtorTest>());
62
63 constexpr size_t D = std::dynamic_extent;
64 using E = std::extents<int, 1, D, 3, D>;
65
66 // check can't construct from too few arguments
67 static_assert(!std::is_constructible_v<E, std::array<int, 1>>, "extents constructible from illegal arguments");
68 // check can't construct from rank_dynamic < #args < rank
69 static_assert(!std::is_constructible_v<E, std::array<int, 3>>, "extents constructible from illegal arguments");
70 // check can't construct from too many arguments
71 static_assert(!std::is_constructible_v<E, std::array<int, 5>>, "extents constructible from illegal arguments");
72
73 // test implicit construction fails from span and array if all extents are given
74 std::array a5{3, 4, 5, 6, 7};
75 // check that explicit construction works, i.e. no error
76 static_assert(std::is_constructible_v< std::extents<int, D, D, 5, D, D>, decltype(a5)>,
77 "extents unexpectedly not constructible");
78 // check that implicit construction doesn't work
79 assert((implicit_construction<std::extents<int, D, D, 5, D, D>>(a5).value == false));
80
81 // test construction fails from types not convertible to index_type but convertible to other integer types
82 static_assert(std::is_convertible_v<IntType, int>, "Test helper IntType unexpectedly not convertible to int");
83 static_assert(!std::is_constructible_v< std::extents<unsigned long, D>, std::array<IntType, 1>>,
84 "extents constructible from illegal arguments");
85
86 // index_type is not nothrow constructible
87 static_assert(std::is_convertible_v<IntType, unsigned char>);
88 static_assert(std::is_convertible_v<const IntType&, unsigned char>);
89 static_assert(!std::is_nothrow_constructible_v<unsigned char, const IntType&>);
90 static_assert(!std::is_constructible_v<std::dextents<unsigned char, 2>, std::array<IntType, 2>>);
91
92 // convertible from non-const to index_type but not from const
93 static_assert(std::is_convertible_v<IntTypeNC, int>);
94 static_assert(!std::is_convertible_v<const IntTypeNC&, int>);
95 static_assert(std::is_nothrow_constructible_v<int, IntTypeNC>);
96 static_assert(!std::is_constructible_v<std::dextents<int, 2>, std::array<IntTypeNC, 2>>);
97 return 0;
98}
99

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