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 // UNSUPPORTED: c++03, c++11, c++14, c++17
10 
11 // <sstream>
12 
13 // template <class charT, class traits, class Allocator>
14 // void swap(basic_stringbuf<charT, traits, Allocator>& x,
15 //           basic_stringbuf<charT, traits, Allocator>& y)
16 //   noexcept(allocator_traits<allocator_type>::propagate_on_container_swap::value ||
17 //            allocator_traits<allocator_type>::is_always_equal::value);
18 
19 #include <sstream>
20 #include <cassert>
21 
22 #include "test_macros.h"
23 
24 template <class T>
25 struct test_alloc {
26   using value_type = T;
27 
28   [[nodiscard]] constexpr T* allocate(std::size_t) { return nullptr; }
29   void deallocate(void*, std::size_t) {}
30 };
31 
32 template <class T>
33 struct test_alloc_propagate_on_container_swap : test_alloc<T> {
34   using propagate_on_container_swap = std::true_type;
35 };
36 
37 template <class T>
38 struct test_alloc_is_always_equal : test_alloc<T> {
39   using is_always_equal = std::true_type;
40 };
41 
42 template <class T>
43 struct test_alloc_propagate_on_container_swap_is_always_equal : test_alloc<T> {
44   using propagate_on_container_swap = std::true_type;
45   using is_always_equal             = std::true_type;
46 };
47 
48 template <class T>
49 struct test_alloc_not_empty : test_alloc<T> {
50   bool dummy;
51 };
52 
53 template <class T>
54 struct test_alloc_propagate_on_container_swap_not_empty : test_alloc<T> {
55   using propagate_on_container_swap = std::true_type;
56   bool dummy;
57 };
58 
59 template <class CharT>
60 static void test() {
61   {
62     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc<CharT>> buf1;
63     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc<CharT>> buf;
64     static_assert(noexcept(swap(buf, buf1)));
65   }
66   {
67     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc_propagate_on_container_swap<CharT>> buf1;
68     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc_propagate_on_container_swap<CharT>> buf;
69     static_assert(noexcept(swap(buf, buf1)));
70   }
71   {
72     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc_is_always_equal<CharT>> buf1;
73     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc_is_always_equal<CharT>> buf;
74     static_assert(noexcept(swap(buf, buf1)));
75   }
76   {
77     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc_propagate_on_container_swap_is_always_equal<CharT>>
78         buf1;
79     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc_propagate_on_container_swap_is_always_equal<CharT>>
80         buf;
81     static_assert(noexcept(swap(buf, buf1)));
82   }
83   {
84     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc_not_empty<CharT>> buf1;
85     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc_not_empty<CharT>> buf;
86     static_assert(!noexcept(swap(buf, buf1)));
87   }
88   {
89     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc_propagate_on_container_swap_not_empty<CharT>> buf1;
90     std::basic_stringbuf<CharT, std::char_traits<CharT>, test_alloc_propagate_on_container_swap_not_empty<CharT>> buf;
91     static_assert(noexcept(swap(buf, buf1)));
92   }
93 }
94 
95 int main(int, char**) {
96   test<char>();
97 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
98   test<wchar_t>();
99 #endif
100   return 0;
101 }
102