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 // <algorithm>
10
11 // UNSUPPORTED: c++03, c++11, c++14, c++17
12
13 // template<input_iterator I, weakly_incrementable O>
14 // requires indirectly_copyable<I, O>
15 // constexpr ranges::copy_n_result<I, O>
16 // ranges::copy_n(I first, iter_difference_t<I> n, O result);
17
18 #include <algorithm>
19 #include <array>
20 #include <cassert>
21 #include <ranges>
22
23 #include "almost_satisfies_types.h"
24 #include "test_iterators.h"
25
26 template <class In, class Out = In, class Count = std::size_t>
27 concept HasCopyNIt = requires(In in, Count count, Out out) { std::ranges::copy_n(in, count, out); };
28
29 static_assert(HasCopyNIt<int*>);
30 static_assert(!HasCopyNIt<InputIteratorNotDerivedFrom>);
31 static_assert(!HasCopyNIt<InputIteratorNotIndirectlyReadable>);
32 static_assert(!HasCopyNIt<InputIteratorNotInputOrOutputIterator>);
33 static_assert(!HasCopyNIt<int*, WeaklyIncrementableNotMovable>);
34 struct NotIndirectlyCopyable {};
35 static_assert(!HasCopyNIt<int*, NotIndirectlyCopyable*>);
36 static_assert(!HasCopyNIt<int*, int*, SentinelForNotSemiregular>);
37 static_assert(!HasCopyNIt<int*, int*, SentinelForNotWeaklyEqualityComparableWith>);
38
39 static_assert(std::is_same_v<std::ranges::copy_result<int, long>, std::ranges::in_out_result<int, long>>);
40
41 template <class In, class Out, class Sent = In>
test_iterators()42 constexpr void test_iterators() {
43 { // simple test
44 std::array in {1, 2, 3, 4};
45 std::array<int, 4> out;
46 std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
47 std::ranges::copy_n(In(in.data()), in.size(), Out(out.data()));
48 assert(in == out);
49 assert(base(ret.in) == in.data() + in.size());
50 assert(base(ret.out) == out.data() + out.size());
51 }
52
53 { // check that an empty range works
54 std::array<int, 0> in;
55 std::array<int, 0> out;
56 auto ret = std::ranges::copy_n(In(in.data()), in.size(), Out(out.data()));
57 assert(base(ret.in) == in.data());
58 assert(base(ret.out) == out.data());
59 }
60 }
61
62 template <class Out>
test_in_iterators()63 constexpr void test_in_iterators() {
64 test_iterators<cpp20_input_iterator<int*>, Out, sentinel_wrapper<cpp20_input_iterator<int*>>>();
65 test_iterators<forward_iterator<int*>, Out>();
66 test_iterators<bidirectional_iterator<int*>, Out>();
67 test_iterators<random_access_iterator<int*>, Out>();
68 test_iterators<contiguous_iterator<int*>, Out>();
69 }
70
71 template <class Out>
test_proxy_in_iterators()72 constexpr void test_proxy_in_iterators() {
73 test_iterators<ProxyIterator<cpp20_input_iterator<int*>>, Out, sentinel_wrapper<ProxyIterator<cpp20_input_iterator<int*>>>>();
74 test_iterators<ProxyIterator<forward_iterator<int*>>, Out>();
75 test_iterators<ProxyIterator<bidirectional_iterator<int*>>, Out>();
76 test_iterators<ProxyIterator<random_access_iterator<int*>>, Out>();
77 test_iterators<ProxyIterator<contiguous_iterator<int*>>, Out>();
78 }
79
test()80 constexpr bool test() {
81 test_in_iterators<cpp20_input_iterator<int*>>();
82 test_in_iterators<forward_iterator<int*>>();
83 test_in_iterators<bidirectional_iterator<int*>>();
84 test_in_iterators<random_access_iterator<int*>>();
85 test_in_iterators<contiguous_iterator<int*>>();
86
87 test_proxy_in_iterators<ProxyIterator<cpp20_input_iterator<int*>>>();
88 test_proxy_in_iterators<ProxyIterator<forward_iterator<int*>>>();
89 test_proxy_in_iterators<ProxyIterator<bidirectional_iterator<int*>>>();
90 test_proxy_in_iterators<ProxyIterator<random_access_iterator<int*>>>();
91 test_proxy_in_iterators<ProxyIterator<contiguous_iterator<int*>>>();
92
93 { // check that every element is copied exactly once
94 struct CopyOnce {
95 bool copied = false;
96 constexpr CopyOnce() = default;
97 constexpr CopyOnce(const CopyOnce& other) = delete;
98 constexpr CopyOnce& operator=(const CopyOnce& other) {
99 assert(!other.copied);
100 copied = true;
101 return *this;
102 }
103 };
104 std::array<CopyOnce, 4> in {};
105 std::array<CopyOnce, 4> out {};
106 auto ret = std::ranges::copy_n(in.begin(), in.size(), out.begin());
107 assert(ret.in == in.end());
108 assert(ret.out == out.end());
109 assert(std::all_of(out.begin(), out.end(), [](const auto& e) { return e.copied; }));
110 }
111
112 return true;
113 }
114
main(int,char **)115 int main(int, char**) {
116 test();
117 static_assert(test());
118
119 return 0;
120 }
121