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 // constexpr span() noexcept;
13 
14 #include <span>
15 #include <cassert>
16 #include <string>
17 #include <type_traits>
18 
19 #include "test_macros.h"
20 
21 void checkCV()
22 {
23 //  Types the same (dynamic sized)
24     {
25     std::span<               int> s1;
26     std::span<const          int> s2;
27     std::span<      volatile int> s3;
28     std::span<const volatile int> s4;
29     assert(s1.size() + s2.size() + s3.size() + s4.size() == 0);
30     }
31 
32 //  Types the same (static sized)
33     {
34     std::span<               int,0> s1;
35     std::span<const          int,0> s2;
36     std::span<      volatile int,0> s3;
37     std::span<const volatile int,0> s4;
38     assert(s1.size() + s2.size() + s3.size() + s4.size() == 0);
39     }
40 }
41 
42 
43 template <typename T>
44 constexpr bool testConstexprSpan()
45 {
46     std::span<const T>    s1;
47     std::span<const T, 0> s2;
48     return
49         s1.data() == nullptr && s1.size() == 0
50     &&  s2.data() == nullptr && s2.size() == 0;
51 }
52 
53 
54 template <typename T>
55 void testRuntimeSpan()
56 {
57     ASSERT_NOEXCEPT(T{});
58     std::span<const T>    s1;
59     std::span<const T, 0> s2;
60     assert(s1.data() == nullptr && s1.size() == 0);
61     assert(s2.data() == nullptr && s2.size() == 0);
62 }
63 
64 
65 struct A{};
66 
67 int main(int, char**)
68 {
69     static_assert(testConstexprSpan<int>(),    "");
70     static_assert(testConstexprSpan<long>(),   "");
71     static_assert(testConstexprSpan<double>(), "");
72     static_assert(testConstexprSpan<A>(),      "");
73 
74     testRuntimeSpan<int>();
75     testRuntimeSpan<long>();
76     testRuntimeSpan<double>();
77     testRuntimeSpan<std::string>();
78     testRuntimeSpan<A>();
79 
80     checkCV();
81 
82     static_assert( std::is_default_constructible_v<std::span<int, std::dynamic_extent>>, "");
83     static_assert( std::is_default_constructible_v<std::span<int, 0>>, "");
84     static_assert(!std::is_default_constructible_v<std::span<int, 2>>, "");
85 
86     return 0;
87 }
88