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
11// <memory>
12
13// template <nothrow-forward-iterator ForwardIterator, class T>
14// requires constructible_from<iter_value_t<ForwardIterator>, const T&>
15// ForwardIterator ranges::uninitialized_fill_n(ForwardIterator first, iter_difference_t<ForwardIterator> n);
16
17#include <algorithm>
18#include <cassert>
19#include <iterator>
20#include <memory>
21#include <ranges>
22#include <type_traits>
23
24#include "../buffer.h"
25#include "../counted.h"
26#include "test_macros.h"
27#include "test_iterators.h"
28
29// TODO(varconst): consolidate the ADL checks into a single file.
30// Because this is a variable and not a function, it's guaranteed that ADL won't be used. However,
31// implementations are allowed to use a different mechanism to achieve this effect, so this check is
32// libc++-specific.
33LIBCPP_STATIC_ASSERT(std::is_class_v<decltype(std::ranges::uninitialized_fill_n)>);
34
35struct NotConvertibleFromInt {};
36static_assert(!std::is_invocable_v<decltype(std::ranges::uninitialized_fill_n), NotConvertibleFromInt*, std::size_t, int>);
37
38int main(int, char**) {
39 constexpr int value = 42;
40 Counted x(value);
41 Counted::reset();
42 auto pred = [](const Counted& e) { return e.value == value; };
43
44 // An empty range -- no default constructors should be invoked.
45 {
46 Buffer<Counted, 1> buf;
47
48 std::ranges::uninitialized_fill_n(buf.begin(), 0, x);
49 assert(Counted::current_objects == 0);
50 assert(Counted::total_objects == 0);
51 }
52
53 // A range containing several objects.
54 {
55 constexpr int N = 5;
56 Buffer<Counted, N> buf;
57
58 std::ranges::uninitialized_fill_n(buf.begin(), N, x);
59 assert(Counted::current_objects == N);
60 assert(Counted::total_objects == N);
61 assert(std::all_of(buf.begin(), buf.end(), pred));
62
63 std::destroy(first: buf.begin(), last: buf.end());
64 Counted::reset();
65 }
66
67 // Any existing values should be overwritten by value constructors.
68 {
69 constexpr int N = 5;
70 int buffer[N] = {value, value, value, value, value};
71
72 std::ranges::uninitialized_fill_n(buffer, 1, 0);
73 assert(buffer[0] == 0);
74 assert(buffer[1] == value);
75
76 std::ranges::uninitialized_fill_n(buffer, N, 0);
77 assert(buffer[0] == 0);
78 assert(buffer[1] == 0);
79 assert(buffer[2] == 0);
80 assert(buffer[3] == 0);
81 assert(buffer[4] == 0);
82 }
83
84 // An exception is thrown while objects are being created -- the existing objects should stay
85 // valid. (iterator, sentinel) overload.
86#ifndef TEST_HAS_NO_EXCEPTIONS
87 {
88 constexpr int N = 5;
89 Buffer<Counted, N> buf;
90
91 Counted::throw_on = 3; // When constructing the fourth object.
92 try {
93 std::ranges::uninitialized_fill_n(buf.begin(), N, x);
94 } catch (...) {
95 }
96 assert(Counted::current_objects == 0);
97 assert(Counted::total_objects == 3);
98
99 std::destroy(first: buf.begin(), last: buf.begin() + 3);
100 Counted::reset();
101 }
102#endif // TEST_HAS_NO_EXCEPTIONS
103
104 return 0;
105}
106

source code of libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill.n/ranges_uninitialized_fill_n.pass.cpp