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 _PartialOrdResult : signed char {
28 __less = static_cast<signed char>(_OrdResult::__less),
29 __equiv = static_cast<signed char>(_OrdResult::__equiv),
30 __greater = static_cast<signed char>(_OrdResult::__greater),
31 __unordered = -127,
32};
33
34class partial_ordering;
35class weak_ordering;
36class strong_ordering;
37
38struct _CmpUnspecifiedParam {
39 // If anything other than a literal 0 is provided, the behavior is undefined by the Standard.
40 //
41 // The alternative to the `__enable_if__` attribute would be to use the fact that a pointer
42 // can be constructed from literal 0, but this conflicts with `-Wzero-as-null-pointer-constant`.
43 template <class _Tp, class = __enable_if_t<is_same_v<_Tp, int> > >
44 _LIBCPP_HIDE_FROM_ABI consteval _CmpUnspecifiedParam(_Tp __zero) noexcept
45# if __has_attribute(__enable_if__)
46 __attribute__((__enable_if__(
47 __zero == 0, "Only literal 0 is allowed as the operand of a comparison with one of the ordering types")))
48# endif
49 {
50 (void)__zero;
51 }
52};
53
54class partial_ordering {
55 _LIBCPP_HIDE_FROM_ABI explicit constexpr partial_ordering(_PartialOrdResult __v) noexcept : __value_(__v) {}
56
57public:
58 // valid values
59 static const partial_ordering less;
60 static const partial_ordering equivalent;
61 static const partial_ordering greater;
62 static const partial_ordering unordered;
63
64 // comparisons
65 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(partial_ordering, partial_ordering) noexcept = default;
66
67 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
68 return __v.__value_ == _PartialOrdResult::__equiv;
69 }
70
71 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
72 return __v.__value_ == _PartialOrdResult::__less;
73 }
74
75 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
76 return __v.__value_ == _PartialOrdResult::__equiv || __v.__value_ == _PartialOrdResult::__less;
77 }
78
79 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
80 return __v.__value_ == _PartialOrdResult::__greater;
81 }
82
83 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
84 return __v.__value_ == _PartialOrdResult::__equiv || __v.__value_ == _PartialOrdResult::__greater;
85 }
86
87 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
88 return __v.__value_ == _PartialOrdResult::__greater;
89 }
90
91 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
92 return __v.__value_ == _PartialOrdResult::__equiv || __v.__value_ == _PartialOrdResult::__greater;
93 }
94
95 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
96 return __v.__value_ == _PartialOrdResult::__less;
97 }
98
99 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
100 return __v.__value_ == _PartialOrdResult::__equiv || __v.__value_ == _PartialOrdResult::__less;
101 }
102
103 _LIBCPP_HIDE_FROM_ABI friend constexpr partial_ordering
104 operator<=>(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
105 return __v;
106 }
107
108 _LIBCPP_HIDE_FROM_ABI friend constexpr partial_ordering
109 operator<=>(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
110 return __v < 0 ? partial_ordering::greater : (__v > 0 ? partial_ordering::less : __v);
111 }
112
113private:
114 _PartialOrdResult __value_;
115};
116
117inline constexpr partial_ordering partial_ordering::less(_PartialOrdResult::__less);
118inline constexpr partial_ordering partial_ordering::equivalent(_PartialOrdResult::__equiv);
119inline constexpr partial_ordering partial_ordering::greater(_PartialOrdResult::__greater);
120inline constexpr partial_ordering partial_ordering::unordered(_PartialOrdResult::__unordered);
121
122class weak_ordering {
123 using _ValueT _LIBCPP_NODEBUG = signed char;
124
125 _LIBCPP_HIDE_FROM_ABI explicit constexpr weak_ordering(_OrdResult __v) noexcept : __value_(_ValueT(__v)) {}
126
127public:
128 static const weak_ordering less;
129 static const weak_ordering equivalent;
130 static const weak_ordering greater;
131
132 _LIBCPP_HIDE_FROM_ABI constexpr operator partial_ordering() const noexcept {
133 return __value_ == 0 ? partial_ordering::equivalent
134 : (__value_ < 0 ? partial_ordering::less : partial_ordering::greater);
135 }
136
137 // comparisons
138 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(weak_ordering, weak_ordering) noexcept = default;
139
140 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
141 return __v.__value_ == 0;
142 }
143
144 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
145 return __v.__value_ < 0;
146 }
147
148 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
149 return __v.__value_ <= 0;
150 }
151
152 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
153 return __v.__value_ > 0;
154 }
155
156 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
157 return __v.__value_ >= 0;
158 }
159
160 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
161 return 0 < __v.__value_;
162 }
163
164 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
165 return 0 <= __v.__value_;
166 }
167
168 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
169 return 0 > __v.__value_;
170 }
171
172 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
173 return 0 >= __v.__value_;
174 }
175
176 _LIBCPP_HIDE_FROM_ABI friend constexpr weak_ordering operator<=>(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
177 return __v;
178 }
179
180 _LIBCPP_HIDE_FROM_ABI friend constexpr weak_ordering operator<=>(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
181 return __v < 0 ? weak_ordering::greater : (__v > 0 ? weak_ordering::less : __v);
182 }
183
184private:
185 _ValueT __value_;
186};
187
188inline constexpr weak_ordering weak_ordering::less(_OrdResult::__less);
189inline constexpr weak_ordering weak_ordering::equivalent(_OrdResult::__equiv);
190inline constexpr weak_ordering weak_ordering::greater(_OrdResult::__greater);
191
192class strong_ordering {
193 using _ValueT _LIBCPP_NODEBUG = signed char;
194
195 _LIBCPP_HIDE_FROM_ABI explicit constexpr strong_ordering(_OrdResult __v) noexcept : __value_(_ValueT(__v)) {}
196
197public:
198 static const strong_ordering less;
199 static const strong_ordering equal;
200 static const strong_ordering equivalent;
201 static const strong_ordering greater;
202
203 // conversions
204 _LIBCPP_HIDE_FROM_ABI constexpr operator partial_ordering() const noexcept {
205 return __value_ == 0 ? partial_ordering::equivalent
206 : (__value_ < 0 ? partial_ordering::less : partial_ordering::greater);
207 }
208
209 _LIBCPP_HIDE_FROM_ABI constexpr operator weak_ordering() const noexcept {
210 return __value_ == 0 ? weak_ordering::equivalent : (__value_ < 0 ? weak_ordering::less : weak_ordering::greater);
211 }
212
213 // comparisons
214 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(strong_ordering, strong_ordering) noexcept = default;
215
216 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
217 return __v.__value_ == 0;
218 }
219
220 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
221 return __v.__value_ < 0;
222 }
223
224 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
225 return __v.__value_ <= 0;
226 }
227
228 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
229 return __v.__value_ > 0;
230 }
231
232 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
233 return __v.__value_ >= 0;
234 }
235
236 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
237 return 0 < __v.__value_;
238 }
239
240 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
241 return 0 <= __v.__value_;
242 }
243
244 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
245 return 0 > __v.__value_;
246 }
247
248 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
249 return 0 >= __v.__value_;
250 }
251
252 _LIBCPP_HIDE_FROM_ABI friend constexpr strong_ordering
253 operator<=>(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
254 return __v;
255 }
256
257 _LIBCPP_HIDE_FROM_ABI friend constexpr strong_ordering
258 operator<=>(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
259 return __v < 0 ? strong_ordering::greater : (__v > 0 ? strong_ordering::less : __v);
260 }
261
262private:
263 _ValueT __value_;
264};
265
266inline constexpr strong_ordering strong_ordering::less(_OrdResult::__less);
267inline constexpr strong_ordering strong_ordering::equal(_OrdResult::__equiv);
268inline constexpr strong_ordering strong_ordering::equivalent(_OrdResult::__equiv);
269inline constexpr strong_ordering strong_ordering::greater(_OrdResult::__greater);
270
271/// [cmp.categories.pre]/1
272/// The types partial_ordering, weak_ordering, and strong_ordering are
273/// collectively termed the comparison category types.
274template <class _Tp>
275concept __comparison_category =
276 is_same_v<_Tp, partial_ordering> || is_same_v<_Tp, weak_ordering> || is_same_v<_Tp, strong_ordering>;
277
278#endif // _LIBCPP_STD_VER >= 20
279
280_LIBCPP_END_NAMESPACE_STD
281
282#endif // _LIBCPP___COMPARE_ORDERING_H
283