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> 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.begin())); 57 assert(base(ret.in) == in.data()); 58 assert(base(ret.out) == out.data()); 59 } 60 } 61 62 template <class Out> 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> 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 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.data(), 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 } 114 115 int main(int, char**) { 116 test(); 117 static_assert(test()); 118 119 return 0; 120 } 121