1 // -*- C++ -*-
2 //===------------------------------ span ---------------------------------===//
3 //
4 //                     The LLVM Compiler Infrastructure
5 //
6 // This file is dual licensed under the MIT and the University of Illinois Open
7 // Source Licenses. See LICENSE.TXT for details.
8 //
9 //===---------------------------------------------------------------------===//
10 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
11 
12 // <span>
13 
14 // constexpr bool empty() const noexcept;
15 //
16 
17 
18 #include <span>
19 #include <cassert>
20 #include <string>
21 
22 #include "test_macros.h"
23 
24 struct A{};
25 constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
26           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
27 
main()28 int main ()
29 {
30     static_assert( noexcept(std::span<int>   ().empty()), "");
31     static_assert( noexcept(std::span<int, 0>().empty()), "");
32 
33 
34     static_assert( std::span<int>().empty(),            "");
35     static_assert( std::span<long>().empty(),           "");
36     static_assert( std::span<double>().empty(),         "");
37     static_assert( std::span<A>().empty(),              "");
38     static_assert( std::span<std::string>().empty(),    "");
39 
40     static_assert( std::span<int, 0>().empty(),         "");
41     static_assert( std::span<long, 0>().empty(),        "");
42     static_assert( std::span<double, 0>().empty(),      "");
43     static_assert( std::span<A, 0>().empty(),           "");
44     static_assert( std::span<std::string, 0>().empty(), "");
45 
46     static_assert(!std::span<const int>(iArr1, 1).empty(), "");
47     static_assert(!std::span<const int>(iArr1, 2).empty(), "");
48     static_assert(!std::span<const int>(iArr1, 3).empty(), "");
49     static_assert(!std::span<const int>(iArr1, 4).empty(), "");
50     static_assert(!std::span<const int>(iArr1, 5).empty(), "");
51 
52     assert( (std::span<int>().empty()           ));
53     assert( (std::span<long>().empty()          ));
54     assert( (std::span<double>().empty()        ));
55     assert( (std::span<A>().empty()             ));
56     assert( (std::span<std::string>().empty()   ));
57 
58     assert( (std::span<int, 0>().empty()        ));
59     assert( (std::span<long, 0>().empty()       ));
60     assert( (std::span<double, 0>().empty()     ));
61     assert( (std::span<A, 0>().empty()          ));
62     assert( (std::span<std::string, 0>().empty()));
63 
64     assert(!(std::span<int, 1>(iArr2, 1).empty()));
65     assert(!(std::span<int, 2>(iArr2, 2).empty()));
66     assert(!(std::span<int, 3>(iArr2, 3).empty()));
67     assert(!(std::span<int, 4>(iArr2, 4).empty()));
68     assert(!(std::span<int, 5>(iArr2, 5).empty()));
69 
70     std::string s;
71     assert( ((std::span<std::string>(&s, (std::ptrdiff_t) 0)).empty()));
72     assert(!((std::span<std::string>(&s, 1).empty())));
73 }
74