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 // UNSUPPORTED: libcpp-has-no-incomplete-ranges
11 
12 // transform_view() requires std::default_initializable<V> &&
13 //                           std::default_initializable<F> = default;
14 
15 #include <ranges>
16 
17 #include <cassert>
18 #include <type_traits>
19 
20 constexpr int buff[] = {1, 2, 3};
21 
22 struct DefaultConstructibleView : std::ranges::view_base {
23   constexpr DefaultConstructibleView() : begin_(buff), end_(buff + 3) { }
24   constexpr int const* begin() const { return begin_; }
25   constexpr int const* end() const { return end_; }
26 private:
27   int const* begin_;
28   int const* end_;
29 };
30 
31 struct DefaultConstructibleFunction {
32   int state_;
33   constexpr DefaultConstructibleFunction() : state_(100) { }
34   constexpr int operator()(int i) const { return i + state_; }
35 };
36 
37 struct NoDefaultCtrView : std::ranges::view_base {
38   NoDefaultCtrView() = delete;
39   int* begin() const;
40   int* end() const;
41 };
42 
43 struct NoDefaultFunction {
44   NoDefaultFunction() = delete;
45   constexpr int operator()(int i) const;
46 };
47 
48 constexpr bool test() {
49   {
50     std::ranges::transform_view<DefaultConstructibleView, DefaultConstructibleFunction> view;
51     assert(view.size() == 3);
52     assert(view[0] == 101);
53     assert(view[1] == 102);
54     assert(view[2] == 103);
55   }
56 
57   {
58     std::ranges::transform_view<DefaultConstructibleView, DefaultConstructibleFunction> view = {};
59     assert(view.size() == 3);
60     assert(view[0] == 101);
61     assert(view[1] == 102);
62     assert(view[2] == 103);
63   }
64 
65   static_assert(!std::is_default_constructible_v<std::ranges::transform_view<NoDefaultCtrView,            DefaultConstructibleFunction>>);
66   static_assert(!std::is_default_constructible_v<std::ranges::transform_view<DefaultConstructibleView, NoDefaultFunction>>);
67   static_assert(!std::is_default_constructible_v<std::ranges::transform_view<NoDefaultCtrView,            NoDefaultFunction>>);
68 
69   return true;
70 }
71 
72 int main(int, char**) {
73   test();
74   static_assert(test());
75 
76   return 0;
77 }
78