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<class T, output_iterator<const T&> O>
14 // constexpr O ranges::fill_n(O first, iter_difference_t<O> n, const T& value);
15
16 #include <algorithm>
17 #include <array>
18 #include <cassert>
19 #include <ranges>
20 #include <string>
21
22 #include "almost_satisfies_types.h"
23 #include "test_iterators.h"
24
25 template <class Iter>
26 concept HasFillN = requires(Iter iter) { std::ranges::fill_n(iter, int{}, int{}); };
27
28 struct WrongType {};
29
30 static_assert(HasFillN<int*>);
31 static_assert(!HasFillN<WrongType*>);
32 static_assert(!HasFillN<OutputIteratorNotIndirectlyWritable>);
33 static_assert(!HasFillN<OutputIteratorNotInputOrOutputIterator>);
34
35 template <class It, class Sent = It>
test_iterators()36 constexpr void test_iterators() {
37 { // simple test
38 int a[3];
39 std::same_as<It> decltype(auto) ret = std::ranges::fill_n(It(a), 3, 1);
40 assert(std::all_of(a, a + 3, [](int i) { return i == 1; }));
41 assert(base(ret) == a + 3);
42 }
43
44 { // check that an empty range works
45 std::array<int, 0> a;
46 auto ret = std::ranges::fill_n(It(a.data()), 0, 1);
47 assert(base(ret) == a.data());
48 }
49 }
50
test()51 constexpr bool test() {
52 test_iterators<cpp17_output_iterator<int*>, sentinel_wrapper<cpp17_output_iterator<int*>>>();
53 test_iterators<cpp20_output_iterator<int*>, sentinel_wrapper<cpp20_output_iterator<int*>>>();
54 test_iterators<forward_iterator<int*>>();
55 test_iterators<bidirectional_iterator<int*>>();
56 test_iterators<random_access_iterator<int*>>();
57 test_iterators<contiguous_iterator<int*>>();
58 test_iterators<int*>();
59
60 { // check that every element is copied once
61 struct S {
62 bool copied = false;
63 constexpr S& operator=(const S&) {
64 assert(!copied);
65 copied = true;
66 return *this;
67 }
68 };
69
70 S a[5];
71 std::ranges::fill_n(a, 5, S {});
72 assert(std::all_of(a, a + 5, [](S& s) { return s.copied; }));
73 }
74
75 { // check that non-trivially copyable items are copied properly
76 std::array<std::string, 10> a;
77 auto ret = std::ranges::fill_n(a.data(), 10, "long long string so no SSO");
78 assert(ret == a.data() + a.size());
79 assert(std::all_of(a.begin(), a.end(), [](auto& s) { return s == "long long string so no SSO"; }));
80 }
81
82 return true;
83 }
84
main(int,char **)85 int main(int, char**) {
86 test();
87 static_assert(test());
88
89 return 0;
90 }
91