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 <class It>
13 // constexpr explicit(Extent != dynamic_extent) span(It first, size_type count);
14 // If Extent is not equal to dynamic_extent, then count shall be equal to Extent.
15 //
16
17
18 #include <span>
19 #include <cassert>
20 #include <iterator>
21 #include <type_traits>
22
23 template <size_t Extent>
test_constructibility()24 constexpr void test_constructibility() {
25 struct Other {};
26 static_assert(std::is_constructible_v<std::span<int, Extent>, int*, size_t>);
27 static_assert(!std::is_constructible_v<std::span<int, Extent>, const int*, size_t>);
28 static_assert(std::is_constructible_v<std::span<const int, Extent>, int*, size_t>);
29 static_assert(std::is_constructible_v<std::span<const int, Extent>, const int*, size_t>);
30 static_assert(!std::is_constructible_v<std::span<int, Extent>, volatile int*, size_t>);
31 static_assert(!std::is_constructible_v<std::span<int, Extent>, const volatile int*, size_t>);
32 static_assert(!std::is_constructible_v<std::span<const int, Extent>, volatile int*, size_t>);
33 static_assert(!std::is_constructible_v<std::span<const int, Extent>, const volatile int*, size_t>);
34 static_assert(!std::is_constructible_v<std::span<volatile int, Extent>, const int*, size_t>);
35 static_assert(!std::is_constructible_v<std::span<volatile int, Extent>, const volatile int*, size_t>);
36 static_assert(
37 !std::is_constructible_v<std::span<int, Extent>, double*, size_t>); // iterator type differs from span type
38 static_assert(!std::is_constructible_v<std::span<int, Extent>, size_t, size_t>);
39 static_assert(!std::is_constructible_v<std::span<int, Extent>, Other*, size_t>); // unrelated iterator type
40 }
41
42 template <class T>
test_ctor()43 constexpr bool test_ctor() {
44 T val[2] = {};
45 auto s1 = std::span<T>(val, 2);
46 auto s2 = std::span<T, 2>(val, 2);
47 assert(s1.data() == std::data(val) && s1.size() == std::size(val));
48 assert(s2.data() == std::data(val) && s2.size() == std::size(val));
49 return true;
50 }
51
test()52 constexpr bool test() {
53 test_constructibility<std::dynamic_extent>();
54 test_constructibility<3>();
55
56 struct A {};
57 test_ctor<int>();
58 test_ctor<A>();
59
60 return true;
61 }
62
main(int,char **)63 int main(int, char**) {
64 test();
65 static_assert(test());
66
67 return 0;
68 }
69