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 inner-iterator& inner-iterator::operator++();
13 //
14 // constexpr decltype(auto) inner-iterator::operator++(int);
15 
16 #include <ranges>
17 
18 #include <cassert>
19 #include <type_traits>
20 #include "test_macros.h"
21 #include "../types.h"
22 
23 struct EmptyView : std::ranges::view_base {
24   constexpr int* begin() const { return nullptr; }
25   constexpr int* end() const { return nullptr; }
26   constexpr static size_t size() { return 0; }
27 };
28 static_assert(std::ranges::forward_range<EmptyView>);
29 static_assert(std::ranges::view<EmptyView>);
30 LIBCPP_STATIC_ASSERT(std::ranges::__tiny_range<EmptyView>);
31 
32 constexpr bool test() {
33   // Can call `inner-iterator::operator++`; `View` is a forward range.
34   {
35     SplitViewForward v("abc def", " ");
36     auto val = *v.begin();
37 
38     // ++i
39     {
40       auto i = val.begin();
41       assert(*i == 'a');
42 
43       decltype(auto) i2 = ++i;
44       static_assert(std::is_lvalue_reference_v<decltype(i2)>);
45       assert(&i2 == &i);
46       assert(*i2 == 'b');
47     }
48 
49     // i++
50     {
51       auto i = val.begin();
52       assert(*i == 'a');
53 
54       decltype(auto) i2 = i++;
55       static_assert(!std::is_reference_v<decltype(i2)>);
56       assert(*i2 == 'a');
57       assert(*i == 'b');
58     }
59   }
60 
61   // Can call `inner-iterator::operator++`; `View` is an input range.
62   {
63     // ++i
64     {
65       SplitViewInput v("abc def", ' ');
66       auto val = *v.begin();
67 
68       auto i = val.begin();
69       assert(*i == 'a');
70 
71       decltype(auto) i2 = ++i;
72       static_assert(std::is_lvalue_reference_v<decltype(i2)>);
73       assert(&i2 == &i);
74       assert(*i2 == 'b');
75     }
76 
77     // i++
78     {
79       SplitViewInput v("abc def", ' ');
80       auto val = *v.begin();
81 
82       auto i = val.begin();
83       assert(*i == 'a');
84 
85       static_assert(std::is_void_v<decltype(i++)>);
86       i++;
87       assert(*i == 'b');
88     }
89   }
90 
91   // Can call `inner-iterator::operator++`; `View` is an input range and `Pattern` is an "empty" range.
92   {
93     // ++i
94     {
95       std::ranges::lazy_split_view<InputView, EmptyView> v("a", EmptyView());
96       auto val = *v.begin();
97 
98       auto i = val.begin();
99       assert(*i.base() == 'a');
100       assert(i != std::default_sentinel);
101 
102       // The iterator doesn't move to the next character but is considered to point to the end.
103       decltype(auto) i2 = ++i;
104       assert(&i2 == &i);
105       assert(*i2.base() == 'a');
106       assert(i2 == std::default_sentinel);
107     }
108 
109     // i++
110     {
111       std::ranges::lazy_split_view<InputView, EmptyView> v("a", EmptyView());
112       auto val = *v.begin();
113 
114       auto i = val.begin();
115       assert(*i.base() == 'a');
116       assert(i != std::default_sentinel);
117 
118       // The iterator doesn't move to the next character but is considered to point to the end.
119       i++;
120       assert(*i.base() == 'a');
121       assert(i == std::default_sentinel);
122     }
123   }
124 
125   return true;
126 }
127 
128 int main(int, char**) {
129   test();
130   static_assert(test());
131 
132   return 0;
133 }
134