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 // constexpr lazy_split_view(View base, Pattern pattern);
13
14 #include <ranges>
15
16 #include <cassert>
17 #include <string_view>
18 #include <utility>
19 #include "types.h"
20
21 struct ViewWithCounting : std::ranges::view_base {
22 int* times_copied = nullptr;
23 int* times_moved = nullptr;
24
ViewWithCountingViewWithCounting25 constexpr ViewWithCounting(int& copies_ctr, int& moves_ctr) : times_copied(&copies_ctr), times_moved(&moves_ctr) {}
26
ViewWithCountingViewWithCounting27 constexpr ViewWithCounting(const ViewWithCounting& rhs)
28 : times_copied(rhs.times_copied)
29 , times_moved(rhs.times_moved) {
30 ++(*times_copied);
31 }
ViewWithCountingViewWithCounting32 constexpr ViewWithCounting(ViewWithCounting&& rhs)
33 : times_copied(rhs.times_copied)
34 , times_moved(rhs.times_moved) {
35 ++(*times_moved);
36 }
37
beginViewWithCounting38 constexpr const char* begin() const { return nullptr; }
endViewWithCounting39 constexpr const char* end() const { return nullptr; }
40
41 constexpr ViewWithCounting& operator=(const ViewWithCounting&) = default;
42 constexpr ViewWithCounting& operator=(ViewWithCounting&&) = default;
operator ==ViewWithCounting43 constexpr bool operator==(const ViewWithCounting&) const { return true; }
44 };
45 static_assert(std::ranges::forward_range<ViewWithCounting>);
46 static_assert(std::ranges::view<ViewWithCounting>);
47
test()48 constexpr bool test() {
49 // Calling the constructor with `(ForwardView, ForwardView)`.
50 {
51 CopyableView input = "abc def";
52 std::ranges::lazy_split_view<CopyableView, CopyableView> v(input, " ");
53 assert(v.base() == input);
54 }
55
56 // Calling the constructor with `(InputView, TinyView)`.
57 {
58 InputView input = "abc def";
59 std::ranges::lazy_split_view<InputView, ForwardTinyView> v(input, ' ');
60 // Note: `InputView` isn't equality comparable.
61 (void)v;
62 }
63
64 // Make sure the arguments are moved, not copied.
65 {
66 using View = ViewWithCounting;
67 using Pattern = ViewWithCounting;
68
69 // Arguments are lvalues.
70 {
71 int view_copied = 0, view_moved = 0, pattern_copied = 0, pattern_moved = 0;
72 View view(view_copied, view_moved);
73 Pattern pattern(pattern_copied, pattern_moved);
74
75 std::ranges::lazy_split_view<View, Pattern> v(view, pattern);
76 assert(view_copied == 1); // The local variable is copied into the argument.
77 assert(view_moved == 1);
78 assert(pattern_copied == 1);
79 assert(pattern_moved == 1);
80 }
81
82 // Arguments are rvalues.
83 {
84 int view_copied = 0, view_moved = 0, pattern_copied = 0, pattern_moved = 0;
85 std::ranges::lazy_split_view<View, Pattern> v(
86 View(view_copied, view_moved), Pattern(pattern_copied, pattern_moved));
87 assert(view_copied == 0);
88 assert(view_moved == 1);
89 assert(pattern_copied == 0);
90 assert(pattern_moved == 1);
91 }
92 }
93
94 return true;
95 }
96
main(int,char **)97 int main(int, char**) {
98 test();
99 static_assert(test());
100
101 return 0;
102 }
103