1 | // __ _____ _____ _____ |
2 | // __| | __| | | | JSON for Modern C++ |
3 | // | | |__ | | | | | | version 3.11.3 |
4 | // |_____|_____|_____|_|___| https://github.com/nlohmann/json |
5 | // |
6 | // SPDX-FileCopyrightText: 2013-2023 Niels Lohmann <https://nlohmann.me> |
7 | // SPDX-License-Identifier: MIT |
8 | |
9 | #pragma once |
10 | |
11 | #include <cstddef> // ptrdiff_t |
12 | #include <iterator> // reverse_iterator |
13 | #include <utility> // declval |
14 | |
15 | #include <nlohmann/detail/abi_macros.hpp> |
16 | |
17 | NLOHMANN_JSON_NAMESPACE_BEGIN |
18 | namespace detail |
19 | { |
20 | |
21 | ////////////////////// |
22 | // reverse_iterator // |
23 | ////////////////////// |
24 | |
25 | /*! |
26 | @brief a template for a reverse iterator class |
27 | |
28 | @tparam Base the base iterator type to reverse. Valid types are @ref |
29 | iterator (to create @ref reverse_iterator) and @ref const_iterator (to |
30 | create @ref const_reverse_iterator). |
31 | |
32 | @requirement The class satisfies the following concept requirements: |
33 | - |
34 | [BidirectionalIterator](https://en.cppreference.com/w/cpp/named_req/BidirectionalIterator): |
35 | The iterator that can be moved can be moved in both directions (i.e. |
36 | incremented and decremented). |
37 | - [OutputIterator](https://en.cppreference.com/w/cpp/named_req/OutputIterator): |
38 | It is possible to write to the pointed-to element (only if @a Base is |
39 | @ref iterator). |
40 | |
41 | @since version 1.0.0 |
42 | */ |
43 | template<typename Base> |
44 | class json_reverse_iterator : public std::reverse_iterator<Base> |
45 | { |
46 | public: |
47 | using difference_type = std::ptrdiff_t; |
48 | /// shortcut to the reverse iterator adapter |
49 | using base_iterator = std::reverse_iterator<Base>; |
50 | /// the reference type for the pointed-to element |
51 | using reference = typename Base::reference; |
52 | |
53 | /// create reverse iterator from iterator |
54 | explicit json_reverse_iterator(const typename base_iterator::iterator_type& it) noexcept |
55 | : base_iterator(it) {} |
56 | |
57 | /// create reverse iterator from base class |
58 | explicit json_reverse_iterator(const base_iterator& it) noexcept : base_iterator(it) {} |
59 | |
60 | /// post-increment (it++) |
61 | json_reverse_iterator operator++(int)& // NOLINT(cert-dcl21-cpp) |
62 | { |
63 | return static_cast<json_reverse_iterator>(base_iterator::operator++(1)); |
64 | } |
65 | |
66 | /// pre-increment (++it) |
67 | json_reverse_iterator& operator++() |
68 | { |
69 | return static_cast<json_reverse_iterator&>(base_iterator::operator++()); |
70 | } |
71 | |
72 | /// post-decrement (it--) |
73 | json_reverse_iterator operator--(int)& // NOLINT(cert-dcl21-cpp) |
74 | { |
75 | return static_cast<json_reverse_iterator>(base_iterator::operator--(1)); |
76 | } |
77 | |
78 | /// pre-decrement (--it) |
79 | json_reverse_iterator& operator--() |
80 | { |
81 | return static_cast<json_reverse_iterator&>(base_iterator::operator--()); |
82 | } |
83 | |
84 | /// add to iterator |
85 | json_reverse_iterator& operator+=(difference_type i) |
86 | { |
87 | return static_cast<json_reverse_iterator&>(base_iterator::operator+=(i)); |
88 | } |
89 | |
90 | /// add to iterator |
91 | json_reverse_iterator operator+(difference_type i) const |
92 | { |
93 | return static_cast<json_reverse_iterator>(base_iterator::operator+(i)); |
94 | } |
95 | |
96 | /// subtract from iterator |
97 | json_reverse_iterator operator-(difference_type i) const |
98 | { |
99 | return static_cast<json_reverse_iterator>(base_iterator::operator-(i)); |
100 | } |
101 | |
102 | /// return difference |
103 | difference_type operator-(const json_reverse_iterator& other) const |
104 | { |
105 | return base_iterator(*this) - base_iterator(other); |
106 | } |
107 | |
108 | /// access to successor |
109 | reference operator[](difference_type n) const |
110 | { |
111 | return *(this->operator+(n)); |
112 | } |
113 | |
114 | /// return the key of an object iterator |
115 | auto key() const -> decltype(std::declval<Base>().key()) |
116 | { |
117 | auto it = --this->base(); |
118 | return it.key(); |
119 | } |
120 | |
121 | /// return the value of an iterator |
122 | reference value() const |
123 | { |
124 | auto it = --this->base(); |
125 | return it.operator * (); |
126 | } |
127 | }; |
128 | |
129 | } // namespace detail |
130 | NLOHMANN_JSON_NAMESPACE_END |
131 | |