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 // UNSUPPORTED: libcpp-no-concepts
11 
12 // template<class I2>
13 //   requires assignable_from<I&, const I2&>
14 //     constexpr counted_iterator& operator=(const counted_iterator<I2>& x);
15 
16 #include <iterator>
17 
18 #include "test_macros.h"
19 #include "test_iterators.h"
20 
21 class AssignableFromIter
22 {
23     int *it_;
24 
25 public:
26     typedef          std::input_iterator_tag                      iterator_category;
27     typedef int                                                   value_type;
28     typedef typename std::iterator_traits<int *>::difference_type difference_type;
29     typedef int *                                                 pointer;
30     typedef int &                                                 reference;
31 
32     constexpr int *base() const {return it_;}
33 
34     AssignableFromIter() = default;
35     explicit constexpr AssignableFromIter(int *it) : it_(it) {}
36     constexpr AssignableFromIter(const forward_iterator<int*>& it) : it_(it.base()) {}
37 
38     constexpr AssignableFromIter& operator=(const forward_iterator<int*> &other) {
39       it_ = other.base();
40       return *this;
41     }
42 
43     constexpr reference operator*() const {return *it_;}
44 
45     constexpr AssignableFromIter& operator++() {++it_; return *this;}
46     constexpr AssignableFromIter operator++(int)
47         {AssignableFromIter tmp(*this); ++(*this); return tmp;}
48 };
49 
50 struct InputOrOutputArchetype {
51   using difference_type = int;
52 
53   int *ptr;
54 
55   int operator*() { return *ptr; }
56   void operator++(int) { ++ptr; }
57   InputOrOutputArchetype& operator++() { ++ptr; return *this; }
58 };
59 
60 constexpr bool test() {
61   int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
62 
63   {
64     static_assert( std::is_assignable_v<std::counted_iterator<forward_iterator<int*>>,
65                                         std::counted_iterator<forward_iterator<int*>>>);
66     static_assert(!std::is_assignable_v<std::counted_iterator<forward_iterator<int*>>,
67                                         std::counted_iterator<random_access_iterator<int*>>>);
68   }
69 
70   {
71     std::counted_iterator iter1(AssignableFromIter{buffer}, 8);
72     std::counted_iterator iter2(forward_iterator<int*>{buffer + 2}, 6);
73     assert(iter1.base().base() == buffer);
74     assert(iter1.count() == 8);
75     std::counted_iterator<AssignableFromIter>& result = (iter1 = iter2);
76     assert(&result == &iter1);
77     assert(iter1.base().base() == buffer + 2);
78     assert(iter1.count() == 6);
79 
80     ASSERT_SAME_TYPE(decltype(iter1 = iter2), std::counted_iterator<AssignableFromIter>&);
81   }
82   {
83     std::counted_iterator iter1(AssignableFromIter{buffer}, 8);
84     const std::counted_iterator iter2(forward_iterator<int*>{buffer + 2}, 6);
85     assert(iter1.base().base() == buffer);
86     assert(iter1.count() == 8);
87     std::counted_iterator<AssignableFromIter>& result = (iter1 = iter2);
88     assert(&result == &iter1);
89     assert(iter1.base().base() == buffer + 2);
90     assert(iter1.count() == 6);
91 
92     ASSERT_SAME_TYPE(decltype(iter1 = iter2), std::counted_iterator<AssignableFromIter>&);
93   }
94 
95   {
96     std::counted_iterator iter1(InputOrOutputArchetype{buffer}, 8);
97     std::counted_iterator iter2(InputOrOutputArchetype{buffer + 2}, 6);
98     assert(iter1.base().ptr == buffer);
99     assert(iter1.count() == 8);
100     std::counted_iterator<InputOrOutputArchetype>& result = (iter1 = iter2);
101     assert(&result == &iter1);
102     assert(iter1.base().ptr == buffer + 2);
103     assert(iter1.count() == 6);
104 
105     ASSERT_SAME_TYPE(decltype(iter1 = iter2), std::counted_iterator<InputOrOutputArchetype>&);
106   }
107   {
108     std::counted_iterator iter1(InputOrOutputArchetype{buffer}, 8);
109     const std::counted_iterator iter2(InputOrOutputArchetype{buffer + 2}, 6);
110     assert(iter1.base().ptr == buffer);
111     assert(iter1.count() == 8);
112     std::counted_iterator<InputOrOutputArchetype>& result = (iter1 = iter2);
113     assert(&result == &iter1);
114     assert(iter1.base().ptr == buffer + 2);
115     assert(iter1.count() == 6);
116 
117     ASSERT_SAME_TYPE(decltype(iter1 = iter2), std::counted_iterator<InputOrOutputArchetype>&);
118   }
119 
120   return true;
121 }
122 
123 int main(int, char**) {
124   test();
125   static_assert(test());
126 
127   return 0;
128 }
129