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 // TODO: make `join_view` non-experimental once D2770 is implemented.
11 // UNSUPPORTED: !c++experimental
12 
13 #include <algorithm>
14 #include <array>
15 #include <cassert>
16 #include <concepts>
17 #include <deque>
18 #include <ranges>
19 #include <vector>
20 
21 #include "test_iterators.h"
22 #include "type_algorithms.h"
23 
24 template <class InContainer, class OutContainer>
25 constexpr void test_containers() {
26   using InIter  = typename InContainer::iterator;
27   using OutIter = typename OutContainer::iterator;
28 
29   {
30     InContainer in{1, 2, 3, 4};
31     OutContainer out(4);
32 
33     std::same_as<std::ranges::in_out_result<InIter, OutIter>> auto ret =
34         std::ranges::copy_n(in.begin(), in.size(), out.begin());
35     assert(std::ranges::equal(in, out));
36     assert(ret.in == in.end());
37     assert(ret.out == out.end());
38   }
39 }
40 
41 template <class Iter, class Sent>
42 constexpr void test_join_view() {
43   auto to_subranges = std::views::transform([](auto& vec) {
44     return std::ranges::subrange(Iter(vec.data()), Sent(Iter(vec.data() + vec.size())));
45   });
46 
47   { // segmented -> contiguous
48     std::vector<std::vector<int>> vectors = {};
49     auto range                            = vectors | to_subranges;
50     std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range.begin(), range.end());
51     std::array<int, 0> arr;
52 
53     std::ranges::copy_n((subrange_vector | std::views::join).begin(),
54                         std::ranges::distance(subrange_vector | std::views::join),
55                         arr.begin());
56     assert(std::ranges::equal(arr, std::array<int, 0>{}));
57   }
58   { // segmented -> contiguous
59     std::vector<std::vector<int>> vectors = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10}, {}};
60     auto range                            = vectors | to_subranges;
61     std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range.begin(), range.end());
62     std::array<int, 10> arr;
63 
64     std::ranges::copy_n((subrange_vector | std::views::join).begin(),
65                         std::ranges::distance(subrange_vector | std::views::join),
66                         arr.begin());
67     assert(std::ranges::equal(arr, std::array{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
68   }
69   { // contiguous -> segmented
70     std::vector<std::vector<int>> vectors = {{0, 0, 0, 0}, {0, 0}, {0, 0, 0, 0}, {}};
71     auto range                            = vectors | to_subranges;
72     std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range.begin(), range.end());
73     std::array arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
74 
75     std::ranges::copy_n(arr.begin(), arr.size(), (subrange_vector | std::views::join).begin());
76     assert(std::ranges::equal(subrange_vector | std::views::join, std::array{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
77   }
78   { // segmented -> segmented
79     std::vector<std::vector<int>> vectors = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10}, {}};
80     auto range1                           = vectors | to_subranges;
81     std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range1.begin(), range1.end());
82     std::vector<std::vector<int>> to_vectors = {{0, 0, 0, 0}, {0, 0, 0, 0}, {}, {0, 0}};
83     auto range2                              = to_vectors | to_subranges;
84     std::vector<std::ranges::subrange<Iter, Sent>> to_subrange_vector(range2.begin(), range2.end());
85 
86     std::ranges::copy_n((subrange_vector | std::views::join).begin(),
87                         std::ranges::distance(subrange_vector | std::views::join),
88                         (to_subrange_vector | std::views::join).begin());
89     assert(std::ranges::equal(to_subrange_vector | std::views::join, std::array{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
90   }
91 }
92 
93 constexpr bool test_constexpr() {
94   test_containers<std::vector<int>, std::vector<int>>();
95 
96   // TODO: this should be cpp20_input_iterator_list, not forward_iterator_list
97   types::for_each(types::forward_iterator_list<int*>{}, []<class Iter> {
98     test_join_view<Iter, Iter>();
99     test_join_view<Iter, sentinel_wrapper<Iter>>();
100     test_join_view<Iter, sized_sentinel<Iter>>();
101   });
102   return true;
103 }
104 
105 int main(int, char**) {
106   test_containers<std::deque<int>, std::deque<int>>();
107   test_containers<std::deque<int>, std::vector<int>>();
108   test_containers<std::vector<int>, std::deque<int>>();
109 
110   test_constexpr();
111   static_assert(test_constexpr());
112 
113   return 0;
114 }
115