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
25enum class _OrdResult : signed char { __less = -1, __equiv = 0, __greater = 1 };
26
27enum class _NCmpResult : signed char { __unordered = -127 };
28
29class partial_ordering;
30class weak_ordering;
31class strong_ordering;
32
33template <class _Tp, class... _Args>
34inline constexpr bool __one_of_v = (is_same_v<_Tp, _Args> || ...);
35
36struct _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
43class 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
54public:
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
110private:
111 _ValueT __value_;
112};
113
114inline constexpr partial_ordering partial_ordering::less(_OrdResult::__less);
115inline constexpr partial_ordering partial_ordering::equivalent(_OrdResult::__equiv);
116inline constexpr partial_ordering partial_ordering::greater(_OrdResult::__greater);
117inline constexpr partial_ordering partial_ordering::unordered(_NCmpResult ::__unordered);
118
119class weak_ordering {
120 using _ValueT = signed char;
121
122 _LIBCPP_HIDE_FROM_ABI explicit constexpr weak_ordering(_OrdResult __v) noexcept : __value_(_ValueT(__v)) {}
123
124public:
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
181private:
182 _ValueT __value_;
183};
184
185inline constexpr weak_ordering weak_ordering::less(_OrdResult::__less);
186inline constexpr weak_ordering weak_ordering::equivalent(_OrdResult::__equiv);
187inline constexpr weak_ordering weak_ordering::greater(_OrdResult::__greater);
188
189class strong_ordering {
190 using _ValueT = signed char;
191
192 _LIBCPP_HIDE_FROM_ABI explicit constexpr strong_ordering(_OrdResult __v) noexcept : __value_(_ValueT(__v)) {}
193
194public:
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
259private:
260 _ValueT __value_;
261};
262
263inline constexpr strong_ordering strong_ordering::less(_OrdResult::__less);
264inline constexpr strong_ordering strong_ordering::equal(_OrdResult::__equiv);
265inline constexpr strong_ordering strong_ordering::equivalent(_OrdResult::__equiv);
266inline 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.
271template <class _Tp>
272concept __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