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
9
10// <span>
11
12// template<size_t N>
13// constexpr span(element_type (&arr)[N]) noexcept;
14//
15// Remarks: These constructors shall not participate in overload resolution unless:
16// - extent == dynamic_extent || N == extent is true, and
17// - remove_pointer_t<decltype(data(arr))>(*)[] is convertible to ElementType(*)[].
18//
19
20#include <cassert>
21#include <span>
22#include <string>
23#include <type_traits>
24
25#include "test_macros.h"
26
27
28void checkCV()
29{
30 int arr[] = {1,2,3};
31 const int carr[] = {4,5,6};
32 volatile int varr[] = {7,8,9};
33 const volatile int cvarr[] = {1,3,5};
34
35// Types the same (dynamic sized)
36 {
37 std::span< int> s1{ arr}; // a span< int> pointing at int.
38 std::span<const int> s2{ carr}; // a span<const int> pointing at const int.
39 std::span< volatile int> s3{ varr}; // a span< volatile int> pointing at volatile int.
40 std::span<const volatile int> s4{cvarr}; // a span<const volatile int> pointing at const volatile int.
41 assert(s1.size() + s2.size() + s3.size() + s4.size() == 12);
42 }
43
44// Types the same (static sized)
45 {
46 std::span< int,3> s1{ arr}; // a span< int> pointing at int.
47 std::span<const int,3> s2{ carr}; // a span<const int> pointing at const int.
48 std::span< volatile int,3> s3{ varr}; // a span< volatile int> pointing at volatile int.
49 std::span<const volatile int,3> s4{cvarr}; // a span<const volatile int> pointing at const volatile int.
50 assert(s1.size() + s2.size() + s3.size() + s4.size() == 12);
51 }
52
53
54// types different (dynamic sized)
55 {
56 std::span<const int> s1{ arr}; // a span<const int> pointing at int.
57 std::span< volatile int> s2{ arr}; // a span< volatile int> pointing at int.
58 std::span< volatile int> s3{ arr}; // a span< volatile int> pointing at const int.
59 std::span<const volatile int> s4{ arr}; // a span<const volatile int> pointing at int.
60 std::span<const volatile int> s5{carr}; // a span<const volatile int> pointing at const int.
61 std::span<const volatile int> s6{varr}; // a span<const volatile int> pointing at volatile int.
62 assert(s1.size() + s2.size() + s3.size() + s4.size() + s5.size() + s6.size() == 18);
63 }
64
65// types different (static sized)
66 {
67 std::span<const int,3> s1{ arr}; // a span<const int> pointing at int.
68 std::span< volatile int,3> s2{ arr}; // a span< volatile int> pointing at int.
69 std::span< volatile int,3> s3{ arr}; // a span< volatile int> pointing at const int.
70 std::span<const volatile int,3> s4{ arr}; // a span<const volatile int> pointing at int.
71 std::span<const volatile int,3> s5{carr}; // a span<const volatile int> pointing at const int.
72 std::span<const volatile int,3> s6{varr}; // a span<const volatile int> pointing at volatile int.
73 assert(s1.size() + s2.size() + s3.size() + s4.size() + s5.size() + s6.size() == 18);
74 }
75}
76
77template<class T>
78constexpr bool testSpan()
79{
80 T val[2] = {};
81
82 ASSERT_NOEXCEPT(std::span<T>{val});
83 ASSERT_NOEXCEPT(std::span<T, 2>{val});
84 ASSERT_NOEXCEPT(std::span<const T>{val});
85 ASSERT_NOEXCEPT(std::span<const T, 2>{val});
86
87 std::span<T> s1 = val;
88 std::span<T, 2> s2 = val;
89 std::span<const T> s3 = val;
90 std::span<const T, 2> s4 = val;
91 assert(s1.data() == val && s1.size() == 2);
92 assert(s2.data() == val && s2.size() == 2);
93 assert(s3.data() == val && s3.size() == 2);
94 assert(s4.data() == val && s4.size() == 2);
95
96 std::span<const int> s5 = {{1,2}};
97#if TEST_STD_VER >= 26
98 std::span<const int, 2> s6({1, 2});
99#else
100 std::span<const int, 2> s6 = {{1,2}};
101#endif
102 assert(s5.size() == 2); // and it dangles
103 assert(s6.size() == 2); // and it dangles
104
105 return true;
106}
107
108
109struct A {};
110
111int main(int, char**)
112{
113 testSpan<int>();
114 testSpan<double>();
115 testSpan<A>();
116 testSpan<std::string>();
117
118 static_assert(testSpan<int>());
119 static_assert(testSpan<double>());
120 static_assert(testSpan<A>());
121
122 checkCV();
123
124 // Size wrong
125 {
126 static_assert(!std::is_constructible<std::span<int, 2>, int (&)[3]>::value, "");
127 }
128
129 // Type wrong
130 {
131 static_assert(!std::is_constructible<std::span<float>, int (&)[3]>::value, "");
132 static_assert(!std::is_constructible<std::span<float, 3>, int (&)[3]>::value, "");
133 }
134
135 // CV wrong (dynamically sized)
136 {
137 static_assert(!std::is_constructible<std::span<int>, const int (&)[3]>::value, "");
138 static_assert(!std::is_constructible<std::span<int>, volatile int (&)[3]>::value, "");
139 static_assert(!std::is_constructible<std::span<int>, const volatile int (&)[3]>::value, "");
140
141 static_assert(!std::is_constructible<std::span<const int>, volatile int (&)[3]>::value, "");
142 static_assert(!std::is_constructible<std::span<const int>, const volatile int (&)[3]>::value, "");
143
144 static_assert(!std::is_constructible<std::span<volatile int>, const int (&)[3]>::value, "");
145 static_assert(!std::is_constructible<std::span<volatile int>, const volatile int (&)[3]>::value, "");
146 }
147
148 // CV wrong (statically sized)
149 {
150 static_assert(!std::is_constructible<std::span<int, 3>, const int (&)[3]>::value, "");
151 static_assert(!std::is_constructible<std::span<int, 3>, volatile int (&)[3]>::value, "");
152 static_assert(!std::is_constructible<std::span<int, 3>, const volatile int (&)[3]>::value, "");
153
154 static_assert(!std::is_constructible<std::span<const int, 3>, volatile int (&)[3]>::value, "");
155 static_assert(!std::is_constructible<std::span<const int, 3>, const volatile int (&)[3]>::value, "");
156
157 static_assert(!std::is_constructible<std::span<volatile int, 3>, const int (&)[3]>::value, "");
158 static_assert(!std::is_constructible<std::span<volatile int, 3>, const volatile int (&)[3]>::value, "");
159 }
160
161 return 0;
162}
163

source code of libcxx/test/std/containers/views/views.span/span.cons/array.pass.cpp