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1 | #ifndef BOOST_LEAF_DETAIL_OPTIONAL_HPP_INCLUDED |
2 | #define BOOST_LEAF_DETAIL_OPTIONAL_HPP_INCLUDED | |
3 | ||
1e59de90 | 4 | // Copyright 2018-2022 Emil Dotchevski and Reverge Studios, Inc. |
20effc67 TL |
5 | |
6 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
7 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
8 | ||
1e59de90 | 9 | #include <boost/leaf/config.hpp> |
20effc67 | 10 | |
20effc67 TL |
11 | #include <utility> |
12 | #include <new> | |
13 | ||
14 | namespace boost { namespace leaf { | |
15 | ||
1e59de90 TL |
16 | namespace leaf_detail |
17 | { | |
18 | template <class T> | |
19 | class optional | |
20effc67 | 20 | { |
1e59de90 TL |
21 | int key_; |
22 | union { T value_; }; | |
20effc67 | 23 | |
1e59de90 | 24 | public: |
20effc67 | 25 | |
1e59de90 | 26 | typedef T value_type; |
20effc67 | 27 | |
1e59de90 TL |
28 | BOOST_LEAF_CONSTEXPR optional() noexcept: |
29 | key_(0) | |
30 | { | |
31 | } | |
20effc67 | 32 | |
1e59de90 TL |
33 | BOOST_LEAF_CONSTEXPR optional( optional const & x ): |
34 | key_(x.key_) | |
35 | { | |
36 | if( x.key_ ) | |
37 | (void) new (&value_) T( x.value_ ); | |
38 | } | |
20effc67 | 39 | |
1e59de90 TL |
40 | BOOST_LEAF_CONSTEXPR optional( optional && x ) noexcept: |
41 | key_(x.key_) | |
42 | { | |
43 | if( x.key_ ) | |
20effc67 | 44 | { |
1e59de90 TL |
45 | (void) new (&value_) T( std::move(x.value_) ); |
46 | x.reset(); | |
20effc67 | 47 | } |
1e59de90 | 48 | } |
20effc67 | 49 | |
1e59de90 TL |
50 | BOOST_LEAF_CONSTEXPR optional( int key, T const & v ): |
51 | key_(key), | |
52 | value_(v) | |
53 | { | |
54 | BOOST_LEAF_ASSERT(!empty()); | |
55 | } | |
20effc67 | 56 | |
1e59de90 TL |
57 | BOOST_LEAF_CONSTEXPR optional( int key, T && v ) noexcept: |
58 | key_(key), | |
59 | value_(std::move(v)) | |
60 | { | |
61 | BOOST_LEAF_ASSERT(!empty()); | |
62 | } | |
20effc67 | 63 | |
1e59de90 TL |
64 | BOOST_LEAF_CONSTEXPR optional & operator=( optional const & x ) |
65 | { | |
66 | reset(); | |
67 | if( int key = x.key() ) | |
20effc67 | 68 | { |
1e59de90 TL |
69 | put(key, x.value_); |
70 | key_ = key; | |
20effc67 | 71 | } |
1e59de90 TL |
72 | return *this; |
73 | } | |
20effc67 | 74 | |
1e59de90 TL |
75 | BOOST_LEAF_CONSTEXPR optional & operator=( optional && x ) noexcept |
76 | { | |
77 | reset(); | |
78 | if( int key = x.key() ) | |
20effc67 | 79 | { |
1e59de90 TL |
80 | put(key, std::move(x.value_)); |
81 | x.reset(); | |
20effc67 | 82 | } |
1e59de90 TL |
83 | return *this; |
84 | } | |
20effc67 | 85 | |
1e59de90 TL |
86 | ~optional() noexcept |
87 | { | |
88 | reset(); | |
89 | } | |
20effc67 | 90 | |
1e59de90 TL |
91 | BOOST_LEAF_CONSTEXPR bool empty() const noexcept |
92 | { | |
93 | return key_==0; | |
94 | } | |
20effc67 | 95 | |
1e59de90 TL |
96 | BOOST_LEAF_CONSTEXPR int key() const noexcept |
97 | { | |
98 | return key_; | |
99 | } | |
20effc67 | 100 | |
1e59de90 TL |
101 | BOOST_LEAF_CONSTEXPR void reset() noexcept |
102 | { | |
103 | if( key_ ) | |
20effc67 | 104 | { |
1e59de90 TL |
105 | value_.~T(); |
106 | key_=0; | |
20effc67 | 107 | } |
1e59de90 | 108 | } |
20effc67 | 109 | |
1e59de90 TL |
110 | BOOST_LEAF_CONSTEXPR T & put( int key, T const & v ) |
111 | { | |
112 | BOOST_LEAF_ASSERT(key); | |
113 | reset(); | |
114 | (void) new(&value_) T(v); | |
115 | key_=key; | |
116 | return value_; | |
117 | } | |
118 | ||
119 | BOOST_LEAF_CONSTEXPR T & put( int key, T && v ) noexcept | |
120 | { | |
121 | BOOST_LEAF_ASSERT(key); | |
122 | reset(); | |
123 | (void) new(&value_) T(std::move(v)); | |
124 | key_=key; | |
125 | return value_; | |
126 | } | |
127 | ||
128 | BOOST_LEAF_CONSTEXPR T const * has_value(int key) const noexcept | |
129 | { | |
130 | BOOST_LEAF_ASSERT(key); | |
131 | return key_==key ? &value_ : 0; | |
132 | } | |
20effc67 | 133 | |
1e59de90 TL |
134 | BOOST_LEAF_CONSTEXPR T * has_value(int key) noexcept |
135 | { | |
136 | BOOST_LEAF_ASSERT(key); | |
137 | return key_==key ? &value_ : 0; | |
138 | } | |
20effc67 | 139 | |
1e59de90 TL |
140 | BOOST_LEAF_CONSTEXPR T const & value(int key) const & noexcept |
141 | { | |
142 | BOOST_LEAF_ASSERT(has_value(key) != 0); | |
143 | return value_; | |
144 | } | |
20effc67 | 145 | |
1e59de90 TL |
146 | BOOST_LEAF_CONSTEXPR T & value(int key) & noexcept |
147 | { | |
148 | BOOST_LEAF_ASSERT(has_value(key) != 0); | |
149 | return value_; | |
150 | } | |
20effc67 | 151 | |
1e59de90 TL |
152 | BOOST_LEAF_CONSTEXPR T const && value(int key) const && noexcept |
153 | { | |
154 | BOOST_LEAF_ASSERT(has_value(key) != 0); | |
155 | return value_; | |
156 | } | |
20effc67 | 157 | |
1e59de90 TL |
158 | BOOST_LEAF_CONSTEXPR T value(int key) && noexcept |
159 | { | |
160 | BOOST_LEAF_ASSERT(has_value(key) != 0); | |
161 | T tmp(std::move(value_)); | |
162 | reset(); | |
163 | return tmp; | |
164 | } | |
165 | }; | |
166 | ||
167 | } | |
20effc67 TL |
168 | |
169 | } } | |
170 | ||
171 | #endif |