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 // UNSUPPORTED: libcpp-has-no-incomplete-ranges
13
14 // template<input_iterator I, weakly_incrementable O>
15 // requires indirectly_copyable<I, O>
16 // constexpr ranges::copy_n_result<I, O>
17 // ranges::copy_n(I first, iter_difference_t<I> n, O result);
18
19 #include <algorithm>
20 #include <array>
21 #include <cassert>
22 #include <ranges>
23
24 #include "almost_satisfies_types.h"
25 #include "test_iterators.h"
26
27 template <class In, class Out = In, class Count = size_t>
28 concept HasCopyNIt = requires(In in, Count count, Out out) { std::ranges::copy_n(in, count, out); };
29
30 static_assert(HasCopyNIt<int*>);
31 static_assert(!HasCopyNIt<InputIteratorNotDerivedFrom>);
32 static_assert(!HasCopyNIt<InputIteratorNotIndirectlyReadable>);
33 static_assert(!HasCopyNIt<InputIteratorNotInputOrOutputIterator>);
34 static_assert(!HasCopyNIt<int*, WeaklyIncrementableNotMovable>);
35 struct NotIndirectlyCopyable {};
36 static_assert(!HasCopyNIt<int*, NotIndirectlyCopyable*>);
37 static_assert(!HasCopyNIt<int*, int*, SentinelForNotSemiregular>);
38 static_assert(!HasCopyNIt<int*, int*, SentinelForNotWeaklyEqualityComparableWith>);
39
40 static_assert(std::is_same_v<std::ranges::copy_result<int, long>, std::ranges::in_out_result<int, long>>);
41
42 template <class In, class Out, class Sent = In>
test_iterators()43 constexpr void test_iterators() {
44 { // simple test
45 std::array in {1, 2, 3, 4};
46 std::array<int, 4> out;
47 std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
48 std::ranges::copy_n(In(in.data()), in.size(), Out(out.data()));
49 assert(in == out);
50 assert(base(ret.in) == in.data() + in.size());
51 assert(base(ret.out) == out.data() + out.size());
52 }
53
54 { // check that an empty range works
55 std::array<int, 0> in;
56 std::array<int, 0> out;
57 auto ret = std::ranges::copy_n(In(in.data()), in.size(), Out(out.begin()));
58 assert(base(ret.in) == in.data());
59 assert(base(ret.out) == out.data());
60 }
61 }
62
63 template <class Out>
test_in_iterators()64 constexpr void test_in_iterators() {
65 test_iterators<cpp20_input_iterator<int*>, Out, sentinel_wrapper<cpp20_input_iterator<int*>>>();
66 test_iterators<forward_iterator<int*>, Out>();
67 test_iterators<bidirectional_iterator<int*>, Out>();
68 test_iterators<random_access_iterator<int*>, Out>();
69 test_iterators<contiguous_iterator<int*>, Out>();
70 }
71
72 template <class Out>
test_proxy_in_iterators()73 constexpr void test_proxy_in_iterators() {
74 test_iterators<ProxyIterator<cpp20_input_iterator<int*>>, Out, sentinel_wrapper<ProxyIterator<cpp20_input_iterator<int*>>>>();
75 test_iterators<ProxyIterator<forward_iterator<int*>>, Out>();
76 test_iterators<ProxyIterator<bidirectional_iterator<int*>>, Out>();
77 test_iterators<ProxyIterator<random_access_iterator<int*>>, Out>();
78 test_iterators<ProxyIterator<contiguous_iterator<int*>>, Out>();
79 }
80
test()81 constexpr bool test() {
82 test_in_iterators<cpp20_input_iterator<int*>>();
83 test_in_iterators<forward_iterator<int*>>();
84 test_in_iterators<bidirectional_iterator<int*>>();
85 test_in_iterators<random_access_iterator<int*>>();
86 test_in_iterators<contiguous_iterator<int*>>();
87
88 test_proxy_in_iterators<ProxyIterator<cpp20_input_iterator<int*>>>();
89 test_proxy_in_iterators<ProxyIterator<forward_iterator<int*>>>();
90 test_proxy_in_iterators<ProxyIterator<bidirectional_iterator<int*>>>();
91 test_proxy_in_iterators<ProxyIterator<random_access_iterator<int*>>>();
92 test_proxy_in_iterators<ProxyIterator<contiguous_iterator<int*>>>();
93
94 { // check that every element is copied exactly once
95 struct CopyOnce {
96 bool copied = false;
97 constexpr CopyOnce() = default;
98 constexpr CopyOnce(const CopyOnce& other) = delete;
99 constexpr CopyOnce& operator=(const CopyOnce& other) {
100 assert(!other.copied);
101 copied = true;
102 return *this;
103 }
104 };
105 std::array<CopyOnce, 4> in {};
106 std::array<CopyOnce, 4> out {};
107 auto ret = std::ranges::copy_n(in.data(), in.size(), out.begin());
108 assert(ret.in == in.end());
109 assert(ret.out == out.end());
110 assert(std::all_of(out.begin(), out.end(), [](const auto& e) { return e.copied; }));
111 }
112
113 return true;
114 }
115
main(int,char **)116 int main(int, char**) {
117 test();
118 static_assert(test());
119
120 return 0;
121 }
122