1 // Copyright (C) 2019-2021 Free Software Foundation, Inc.
2 //
3 // This file is part of the GNU ISO C++ Library. This library is free
4 // software; you can redistribute it and/or modify it under the
5 // terms of the GNU General Public License as published by the
6 // Free Software Foundation; either version 3, or (at your option)
7 // any later version.
8
9 // This library is distributed in the hope that it will be useful,
10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 // GNU General Public License for more details.
13
14 // You should have received a copy of the GNU General Public License along
15 // with this library; see the file COPYING3. If not see
16 // <http://www.gnu.org/licenses/>.
17
18 // { dg-options "-std=gnu++2a" }
19 // { dg-do run { target c++2a } }
20
21 #include <ranges>
22 #include <testsuite_hooks.h>
23 #include <testsuite_iterators.h>
24
25 using std::same_as;
26
27 void
test01()28 test01()
29 {
30 struct R
31 {
32 constexpr int empty() const & { return 0; }
33 constexpr const void* empty() const && { return this; }
34 };
35 constexpr R r;
36 static_assert( !std::ranges::empty(r) );
37 static_assert( same_as<decltype(std::ranges::empty(r)), bool> );
38 // PR libstdc++/100824
39 // ranges::empty should treat the subexpression as an lvalue
40 static_assert( !std::ranges::empty(std::move(r)) );
41 static_assert( same_as<decltype(std::ranges::empty(std::move(r))), bool> );
42 }
43
44 void
test02()45 test02()
46 {
47 using __gnu_test::test_range;
48 using __gnu_test::test_sized_range;
49 using __gnu_test::random_access_iterator_wrapper;
50 using __gnu_test::forward_iterator_wrapper;
51 using __gnu_test::input_iterator_wrapper;
52 using __gnu_test::output_iterator_wrapper;
53
54 int a[] = { 0, 1 };
55 VERIFY( !std::ranges::empty(a) );
56
57 test_range<int, random_access_iterator_wrapper> r(a);
58 VERIFY( !std::ranges::empty(r) );
59
60 test_range<int, forward_iterator_wrapper> i(a);
61 VERIFY( !std::ranges::empty(i) );
62
63 test_sized_range<int, random_access_iterator_wrapper> sr(a);
64 VERIFY( !std::ranges::empty(sr) );
65
66 test_sized_range<int, input_iterator_wrapper> si(a);
67 VERIFY( !std::ranges::empty(si) );
68
69 test_sized_range<int, output_iterator_wrapper> so(a);
70 VERIFY( !std::ranges::empty(so) );
71 }
72
73 void
test03()74 test03()
75 {
76 // PR libstdc++/100824
77 // ranges::empty should treat the subexpression as an lvalue
78
79 struct R
80 {
81 constexpr bool empty() & { return true; }
82 };
83 static_assert( std::ranges::empty(R{}) );
84
85 struct R2
86 {
87 constexpr unsigned size() & { return 0; }
88 };
89 static_assert( std::ranges::empty(R2{}) );
90 }
91
92 void
test04()93 test04()
94 {
95 struct E1
96 {
97 bool empty() const noexcept { return {}; }
98 };
99
100 static_assert( noexcept(std::ranges::empty(E1{})) );
101
102 struct E2
103 {
104 bool empty() const noexcept(false) { return {}; }
105 };
106
107 static_assert( ! noexcept(std::ranges::empty(E2{})) );
108
109 struct E3
110 {
111 struct B
112 {
113 explicit operator bool() const noexcept(false) { return true; }
114 };
115
116 B empty() const noexcept { return {}; }
117 };
118
119 static_assert( ! noexcept(std::ranges::empty(E3{})) );
120 }
121
122 int
main()123 main()
124 {
125 test01();
126 test02();
127 test03();
128 test04();
129 }
130