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 #ifndef _LIBCPP___COMPARE_ORDERING_H
10 #define _LIBCPP___COMPARE_ORDERING_H
11 
12 #include <__config>
13 #include <__type_traits/enable_if.h>
14 #include <__type_traits/is_same.h>
15 
16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17 #  pragma GCC system_header
18 #endif
19 
20 _LIBCPP_BEGIN_NAMESPACE_STD
21 
22 #if _LIBCPP_STD_VER >= 20
23 
24 // exposition only
25 enum class _OrdResult : signed char { __less = -1, __equiv = 0, __greater = 1 };
26 
27 enum class _NCmpResult : signed char { __unordered = -127 };
28 
29 class partial_ordering;
30 class weak_ordering;
31 class strong_ordering;
32 
33 template <class _Tp, class... _Args>
34 inline constexpr bool __one_of_v = (is_same_v<_Tp, _Args> || ...);
35 
36 struct _CmpUnspecifiedParam {
37   _LIBCPP_HIDE_FROM_ABI constexpr _CmpUnspecifiedParam(int _CmpUnspecifiedParam::*) noexcept {}
38 
39   template <class _Tp, class = enable_if_t<!__one_of_v<_Tp, int, partial_ordering, weak_ordering, strong_ordering>>>
40   _CmpUnspecifiedParam(_Tp) = delete;
41 };
42 
43 class partial_ordering {
44   using _ValueT = signed char;
45 
46   _LIBCPP_HIDE_FROM_ABI explicit constexpr partial_ordering(_OrdResult __v) noexcept : __value_(_ValueT(__v)) {}
47 
48   _LIBCPP_HIDE_FROM_ABI explicit constexpr partial_ordering(_NCmpResult __v) noexcept : __value_(_ValueT(__v)) {}
49 
50   _LIBCPP_HIDE_FROM_ABI constexpr bool __is_ordered() const noexcept {
51     return __value_ != _ValueT(_NCmpResult::__unordered);
52   }
53 
54 public:
55   // valid values
56   static const partial_ordering less;
57   static const partial_ordering equivalent;
58   static const partial_ordering greater;
59   static const partial_ordering unordered;
60 
61   // comparisons
62   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(partial_ordering, partial_ordering) noexcept = default;
63 
64   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
65     return __v.__is_ordered() && __v.__value_ == 0;
66   }
67 
68   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
69     return __v.__is_ordered() && __v.__value_ < 0;
70   }
71 
72   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
73     return __v.__is_ordered() && __v.__value_ <= 0;
74   }
75 
76   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
77     return __v.__is_ordered() && __v.__value_ > 0;
78   }
79 
80   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
81     return __v.__is_ordered() && __v.__value_ >= 0;
82   }
83 
84   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
85     return __v.__is_ordered() && 0 < __v.__value_;
86   }
87 
88   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
89     return __v.__is_ordered() && 0 <= __v.__value_;
90   }
91 
92   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
93     return __v.__is_ordered() && 0 > __v.__value_;
94   }
95 
96   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
97     return __v.__is_ordered() && 0 >= __v.__value_;
98   }
99 
100   _LIBCPP_HIDE_FROM_ABI friend constexpr partial_ordering
101   operator<=>(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
102     return __v;
103   }
104 
105   _LIBCPP_HIDE_FROM_ABI friend constexpr partial_ordering
106   operator<=>(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
107     return __v < 0 ? partial_ordering::greater : (__v > 0 ? partial_ordering::less : __v);
108   }
109 
110 private:
111   _ValueT __value_;
112 };
113 
114 inline constexpr partial_ordering partial_ordering::less(_OrdResult::__less);
115 inline constexpr partial_ordering partial_ordering::equivalent(_OrdResult::__equiv);
116 inline constexpr partial_ordering partial_ordering::greater(_OrdResult::__greater);
117 inline constexpr partial_ordering partial_ordering::unordered(_NCmpResult ::__unordered);
118 
119 class weak_ordering {
120   using _ValueT = signed char;
121 
122   _LIBCPP_HIDE_FROM_ABI explicit constexpr weak_ordering(_OrdResult __v) noexcept : __value_(_ValueT(__v)) {}
123 
124 public:
125   static const weak_ordering less;
126   static const weak_ordering equivalent;
127   static const weak_ordering greater;
128 
129   _LIBCPP_HIDE_FROM_ABI constexpr operator partial_ordering() const noexcept {
130     return __value_ == 0 ? partial_ordering::equivalent
131                          : (__value_ < 0 ? partial_ordering::less : partial_ordering::greater);
132   }
133 
134   // comparisons
135   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(weak_ordering, weak_ordering) noexcept = default;
136 
137   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
138     return __v.__value_ == 0;
139   }
140 
141   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
142     return __v.__value_ < 0;
143   }
144 
145   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
146     return __v.__value_ <= 0;
147   }
148 
149   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
150     return __v.__value_ > 0;
151   }
152 
153   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
154     return __v.__value_ >= 0;
155   }
156 
157   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
158     return 0 < __v.__value_;
159   }
160 
161   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
162     return 0 <= __v.__value_;
163   }
164 
165   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
166     return 0 > __v.__value_;
167   }
168 
169   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
170     return 0 >= __v.__value_;
171   }
172 
173   _LIBCPP_HIDE_FROM_ABI friend constexpr weak_ordering operator<=>(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
174     return __v;
175   }
176 
177   _LIBCPP_HIDE_FROM_ABI friend constexpr weak_ordering operator<=>(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
178     return __v < 0 ? weak_ordering::greater : (__v > 0 ? weak_ordering::less : __v);
179   }
180 
181 private:
182   _ValueT __value_;
183 };
184 
185 inline constexpr weak_ordering weak_ordering::less(_OrdResult::__less);
186 inline constexpr weak_ordering weak_ordering::equivalent(_OrdResult::__equiv);
187 inline constexpr weak_ordering weak_ordering::greater(_OrdResult::__greater);
188 
189 class strong_ordering {
190   using _ValueT = signed char;
191 
192   _LIBCPP_HIDE_FROM_ABI explicit constexpr strong_ordering(_OrdResult __v) noexcept : __value_(_ValueT(__v)) {}
193 
194 public:
195   static const strong_ordering less;
196   static const strong_ordering equal;
197   static const strong_ordering equivalent;
198   static const strong_ordering greater;
199 
200   // conversions
201   _LIBCPP_HIDE_FROM_ABI constexpr operator partial_ordering() const noexcept {
202     return __value_ == 0 ? partial_ordering::equivalent
203                          : (__value_ < 0 ? partial_ordering::less : partial_ordering::greater);
204   }
205 
206   _LIBCPP_HIDE_FROM_ABI constexpr operator weak_ordering() const noexcept {
207     return __value_ == 0 ? weak_ordering::equivalent : (__value_ < 0 ? weak_ordering::less : weak_ordering::greater);
208   }
209 
210   // comparisons
211   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(strong_ordering, strong_ordering) noexcept = default;
212 
213   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
214     return __v.__value_ == 0;
215   }
216 
217   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
218     return __v.__value_ < 0;
219   }
220 
221   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
222     return __v.__value_ <= 0;
223   }
224 
225   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
226     return __v.__value_ > 0;
227   }
228 
229   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
230     return __v.__value_ >= 0;
231   }
232 
233   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
234     return 0 < __v.__value_;
235   }
236 
237   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
238     return 0 <= __v.__value_;
239   }
240 
241   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
242     return 0 > __v.__value_;
243   }
244 
245   _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
246     return 0 >= __v.__value_;
247   }
248 
249   _LIBCPP_HIDE_FROM_ABI friend constexpr strong_ordering
250   operator<=>(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
251     return __v;
252   }
253 
254   _LIBCPP_HIDE_FROM_ABI friend constexpr strong_ordering
255   operator<=>(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
256     return __v < 0 ? strong_ordering::greater : (__v > 0 ? strong_ordering::less : __v);
257   }
258 
259 private:
260   _ValueT __value_;
261 };
262 
263 inline constexpr strong_ordering strong_ordering::less(_OrdResult::__less);
264 inline constexpr strong_ordering strong_ordering::equal(_OrdResult::__equiv);
265 inline constexpr strong_ordering strong_ordering::equivalent(_OrdResult::__equiv);
266 inline constexpr strong_ordering strong_ordering::greater(_OrdResult::__greater);
267 
268 /// [cmp.categories.pre]/1
269 /// The types partial_ordering, weak_ordering, and strong_ordering are
270 /// collectively termed the comparison category types.
271 template <class _Tp>
272 concept __comparison_category = __one_of_v<_Tp, partial_ordering, weak_ordering, strong_ordering>;
273 
274 #endif // _LIBCPP_STD_VER >= 20
275 
276 _LIBCPP_END_NAMESPACE_STD
277 
278 #endif // _LIBCPP___COMPARE_ORDERING_H
279