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// <array>
10
11// template <class T, size_t N> void swap(array<T,N>& x, array<T,N>& y);
12
13#include <array>
14#include <cassert>
15#include <utility>
16
17#include "test_macros.h"
18
19struct NonSwappable {
20 TEST_CONSTEXPR NonSwappable() {}
21
22private:
23 NonSwappable(NonSwappable const&);
24 NonSwappable& operator=(NonSwappable const&);
25};
26
27template <class Tp>
28decltype(swap(std::declval<Tp>(), std::declval<Tp>())) can_swap_imp(int);
29
30template <class Tp>
31std::false_type can_swap_imp(...);
32
33template <class Tp>
34struct can_swap : std::is_same<decltype(can_swap_imp<Tp>(0)), void> {};
35
36TEST_CONSTEXPR_CXX20 bool tests() {
37 {
38 typedef double T;
39 typedef std::array<T, 3> C;
40 C c1 = {1, 2, 3.5};
41 C c2 = {4, 5, 6.5};
42 swap(one&: c1, two&: c2);
43 assert(c1.size() == 3);
44 assert(c1[0] == 4);
45 assert(c1[1] == 5);
46 assert(c1[2] == 6.5);
47 assert(c2.size() == 3);
48 assert(c2[0] == 1);
49 assert(c2[1] == 2);
50 assert(c2[2] == 3.5);
51 }
52 {
53 typedef double T;
54 typedef std::array<T, 0> C;
55 C c1 = {};
56 C c2 = {};
57 swap(one&: c1, two&: c2);
58 assert(c1.size() == 0);
59 assert(c2.size() == 0);
60 }
61 {
62 typedef NonSwappable T;
63 typedef std::array<T, 0> C0;
64 static_assert(can_swap<C0&>::value, "");
65 C0 l = {};
66 C0 r = {};
67 swap(one&: l, two&: r);
68#if TEST_STD_VER >= 11
69 static_assert(noexcept(swap(l, r)), "");
70#endif
71 }
72#if TEST_STD_VER >= 11
73 {
74 // NonSwappable is still considered swappable in C++03 because there
75 // is no access control SFINAE.
76 typedef NonSwappable T;
77 typedef std::array<T, 42> C1;
78 static_assert(!can_swap<C1&>::value, "");
79 }
80#endif
81
82 return true;
83}
84
85int main(int, char**) {
86 tests();
87#if TEST_STD_VER >= 20
88 static_assert(tests(), "");
89#endif
90 return 0;
91}
92

source code of libcxx/test/std/containers/sequences/array/array.special/swap.pass.cpp