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 // template <input_range Range>
13 // requires constructible_from<View, views::all_t<Range>> &&
14 // constructible_from<Pattern, single_view<range_value_t<Range>>>
15 // constexpr lazy_split_view(Range&& r, range_value_t<Range> e);
16
17 #include <ranges>
18
19 #include <cassert>
20 #include <string>
21 #include <string_view>
22 #include <type_traits>
23 #include <utility>
24 #include "types.h"
25
26 struct ElementWithCounting {
27 int* times_copied = nullptr;
28 int* times_moved = nullptr;
29
ElementWithCountingElementWithCounting30 constexpr ElementWithCounting(int& copies_ctr, int& moves_ctr) : times_copied(&copies_ctr), times_moved(&moves_ctr) {}
31
ElementWithCountingElementWithCounting32 constexpr ElementWithCounting(const ElementWithCounting& rhs)
33 : times_copied(rhs.times_copied)
34 , times_moved(rhs.times_moved) {
35 ++(*times_copied);
36 }
ElementWithCountingElementWithCounting37 constexpr ElementWithCounting(ElementWithCounting&& rhs)
38 : times_copied(rhs.times_copied)
39 , times_moved(rhs.times_moved) {
40 ++(*times_moved);
41 }
42
operator ==ElementWithCounting43 constexpr bool operator==(const ElementWithCounting&) const { return true; }
44 };
45
46 struct RangeWithCounting {
47 using value_type = ElementWithCounting;
48
49 int* times_copied = nullptr;
50 int* times_moved = nullptr;
51
RangeWithCountingRangeWithCounting52 constexpr RangeWithCounting(int& copies_ctr, int& moves_ctr) : times_copied(&copies_ctr), times_moved(&moves_ctr) {}
53
RangeWithCountingRangeWithCounting54 constexpr RangeWithCounting(const RangeWithCounting& rhs)
55 : times_copied(rhs.times_copied)
56 , times_moved(rhs.times_moved) {
57 ++(*times_copied);
58 }
RangeWithCountingRangeWithCounting59 constexpr RangeWithCounting(RangeWithCounting&& rhs)
60 : times_copied(rhs.times_copied)
61 , times_moved(rhs.times_moved) {
62 ++(*times_moved);
63 }
64
beginRangeWithCounting65 constexpr const ElementWithCounting* begin() const { return nullptr; }
endRangeWithCounting66 constexpr const ElementWithCounting* end() const { return nullptr; }
67
68 constexpr RangeWithCounting& operator=(const RangeWithCounting&) = default;
69 constexpr RangeWithCounting& operator=(RangeWithCounting&&) = default;
operator ==RangeWithCounting70 constexpr bool operator==(const RangeWithCounting&) const { return true; }
71 };
72 static_assert( std::ranges::forward_range<RangeWithCounting>);
73 static_assert(!std::ranges::view<RangeWithCounting>);
74
75 struct StrView : std::ranges::view_base {
76 std::string_view buffer_;
77 constexpr explicit StrView() = default;
StrViewStrView78 constexpr StrView(const char* ptr) : buffer_(ptr) {}
79 // Intentionally don't forward to range constructor for std::string_view since
80 // this test needs to work on C++20 as well and the range constructor is only for
81 // C++23 and later.
82 template <std::ranges::range R>
StrViewStrView83 constexpr StrView(R&& r) : buffer_(r.begin(), r.end()) {}
beginStrView84 constexpr const char* begin() const { return buffer_.begin(); }
endStrView85 constexpr const char* end() const { return buffer_.end(); }
operator ==StrView86 constexpr bool operator==(const StrView& rhs) const { return buffer_ == rhs.buffer_; }
87 };
88 static_assert( std::ranges::random_access_range<StrView>);
89 static_assert( std::ranges::view<StrView>);
90 static_assert( std::is_copy_constructible_v<StrView>);
91
test()92 constexpr bool test() {
93 {
94 using V = std::ranges::lazy_split_view<StrView, StrView>;
95
96 // Calling the constructor with `(std::string, range_value_t)`.
97 {
98 std::string input;
99 V v(input, ' ');
100 assert(v.base() == input);
101 }
102
103 // Calling the constructor with `(StrView, range_value_t)`.
104 {
105 StrView input("abc def");
106 V v(input, ' ');
107 assert(v.base() == input);
108 }
109
110 struct Empty {};
111 static_assert(!std::is_constructible_v<V, Empty, std::string_view>);
112 static_assert(!std::is_constructible_v<V, std::string_view, Empty>);
113 }
114
115 // Make sure the arguments are moved, not copied.
116 {
117 using Range = RangeWithCounting;
118 using Element = ElementWithCounting;
119 using Pattern = std::ranges::single_view<Element>;
120
121 // Arguments are lvalues.
122 {
123 using View = std::ranges::ref_view<Range>;
124
125 int range_copied = 0, range_moved = 0, element_copied = 0, element_moved = 0;
126 Range range(range_copied, range_moved);
127 Element element(element_copied, element_moved);
128
129 std::ranges::lazy_split_view<View, Pattern> v(range, element);
130 assert(range_copied == 0); // `ref_view` does neither copy...
131 assert(range_moved == 0); // ...nor move the element.
132 assert(element_copied == 1); // The element is copied into the argument...
133 assert(element_moved == 1); // ...and moved into the member variable.
134 }
135
136 // Arguments are rvalues.
137 {
138 using View = std::ranges::owning_view<Range>;
139
140 int range_copied = 0, range_moved = 0, element_copied = 0, element_moved = 0;
141 std::ranges::lazy_split_view<View, Pattern> v(
142 Range(range_copied, range_moved), Element(element_copied, element_moved));
143 assert(range_copied == 0);
144 assert(range_moved == 1); // `owning_view` moves the given argument.
145 assert(element_copied == 0);
146 assert(element_moved == 1);
147 }
148 }
149
150 return true;
151 }
152
main(int,char **)153 int main(int, char**) {
154 test();
155 static_assert(test());
156
157 return 0;
158 }
159