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 
9 // <utility>
10 
11 // template<ValueType T, size_t N>
12 //   requires Swappable<T>
13 //   void
14 //   swap(T (&a)[N], T (&b)[N]);
15 
16 #include <algorithm>
17 #include <cassert>
18 #include <memory>
19 #include <type_traits>
20 #include <utility>
21 
22 #include "test_macros.h"
23 
24 
25 #if TEST_STD_VER >= 11
26 struct CopyOnly {
27     CopyOnly() {}
28     CopyOnly(CopyOnly const&) noexcept {}
29     CopyOnly& operator=(CopyOnly const&) { return *this; }
30 };
31 
32 
33 struct NoexceptMoveOnly {
34     NoexceptMoveOnly() {}
35     NoexceptMoveOnly(NoexceptMoveOnly&&) noexcept {}
36     NoexceptMoveOnly& operator=(NoexceptMoveOnly&&) noexcept { return *this; }
37 };
38 
39 struct NotMoveConstructible {
40     NotMoveConstructible() {}
41     NotMoveConstructible& operator=(NotMoveConstructible&&) { return *this; }
42 private:
43     NotMoveConstructible(NotMoveConstructible&&);
44 };
45 
46 template <class Tp>
47 auto can_swap_test(int) -> decltype(std::swap(std::declval<Tp>(), std::declval<Tp>()));
48 
49 template <class Tp>
50 auto can_swap_test(...) -> std::false_type;
51 
52 template <class Tp>
53 constexpr bool can_swap() {
54     return std::is_same<decltype(can_swap_test<Tp>(0)), void>::value;
55 }
56 #endif
57 
58 #if TEST_STD_VER > 17
59 constexpr bool test_swap_constexpr()
60 {
61     int i[3] = {1, 2, 3};
62     int j[3] = {4, 5, 6};
63     std::swap(i, j);
64     return i[0] == 4 &&
65            i[1] == 5 &&
66            i[2] == 6 &&
67            j[0] == 1 &&
68            j[1] == 2 &&
69            j[2] == 3;
70 }
71 #endif // TEST_STD_VER > 17
72 
73 int main(int, char**)
74 {
75     {
76         int i[3] = {1, 2, 3};
77         int j[3] = {4, 5, 6};
78         std::swap(i, j);
79         assert(i[0] == 4);
80         assert(i[1] == 5);
81         assert(i[2] == 6);
82         assert(j[0] == 1);
83         assert(j[1] == 2);
84         assert(j[2] == 3);
85     }
86 #if TEST_STD_VER >= 11
87     {
88         std::unique_ptr<int> i[3];
89         for (int k = 0; k < 3; ++k)
90             i[k].reset(new int(k+1));
91         std::unique_ptr<int> j[3];
92         for (int k = 0; k < 3; ++k)
93             j[k].reset(new int(k+4));
94         std::swap(i, j);
95         assert(*i[0] == 4);
96         assert(*i[1] == 5);
97         assert(*i[2] == 6);
98         assert(*j[0] == 1);
99         assert(*j[1] == 2);
100         assert(*j[2] == 3);
101     }
102     {
103         using CA = CopyOnly[42];
104         using MA = NoexceptMoveOnly[42];
105         using NA = NotMoveConstructible[42];
106         static_assert(can_swap<CA&>(), "");
107         static_assert(can_swap<MA&>(), "");
108         static_assert(!can_swap<NA&>(), "");
109 
110         CA ca;
111         MA ma;
112         static_assert(!noexcept(std::swap(ca, ca)), "");
113         static_assert(noexcept(std::swap(ma, ma)), "");
114     }
115 #endif
116 
117 #if TEST_STD_VER > 17
118     static_assert(test_swap_constexpr());
119 #endif // TEST_STD_VER > 17
120 
121   return 0;
122 }
123