2 //===----------------------------------------------------------------------===//
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
8 //===----------------------------------------------------------------------===//
10 #ifndef _LIBCPP_EXPERIMENTAL_PROPAGATE_CONST
11 #define _LIBCPP_EXPERIMENTAL_PROPAGATE_CONST
14 propagate_const synopsis
16 namespace std { namespace experimental { inline namespace fundamentals_v2 {
19 template <class T> class propagate_const;
21 // [propagate_const.underlying], underlying pointer access
22 constexpr const _Tp& get_underlying(const propagate_const<T>& pt) noexcept;
23 constexpr T& get_underlying(propagate_const<T>& pt) noexcept;
25 // [propagate_const.relational], relational operators
26 template <class T> constexpr bool operator==(const propagate_const<T>& pt, nullptr_t);
27 template <class T> constexpr bool operator==(nullptr_t, const propagate_const<T>& pu);
28 template <class T> constexpr bool operator!=(const propagate_const<T>& pt, nullptr_t);
29 template <class T> constexpr bool operator!=(nullptr_t, const propagate_const<T>& pu);
30 template <class T, class U> constexpr bool operator==(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
31 template <class T, class U> constexpr bool operator!=(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
32 template <class T, class U> constexpr bool operator<(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
33 template <class T, class U> constexpr bool operator>(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
34 template <class T, class U> constexpr bool operator<=(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
35 template <class T, class U> constexpr bool operator>=(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
36 template <class T, class U> constexpr bool operator==(const propagate_const<T>& pt, const _Up& u);
37 template <class T, class U> constexpr bool operator!=(const propagate_const<T>& pt, const _Up& u);
38 template <class T, class U> constexpr bool operator<(const propagate_const<T>& pt, const _Up& u);
39 template <class T, class U> constexpr bool operator>(const propagate_const<T>& pt, const _Up& u);
40 template <class T, class U> constexpr bool operator<=(const propagate_const<T>& pt, const _Up& u);
41 template <class T, class U> constexpr bool operator>=(const propagate_const<T>& pt, const _Up& u);
42 template <class T, class U> constexpr bool operator==(const _Tp& t, const propagate_const<_Up>& pu);
43 template <class T, class U> constexpr bool operator!=(const _Tp& t, const propagate_const<_Up>& pu);
44 template <class T, class U> constexpr bool operator<(const _Tp& t, const propagate_const<_Up>& pu);
45 template <class T, class U> constexpr bool operator>(const _Tp& t, const propagate_const<_Up>& pu);
46 template <class T, class U> constexpr bool operator<=(const _Tp& t, const propagate_const<_Up>& pu);
47 template <class T, class U> constexpr bool operator>=(const _Tp& t, const propagate_const<_Up>& pu);
49 // [propagate_const.algorithms], specialized algorithms
50 template <class T> constexpr void swap(propagate_const<T>& pt, propagate_const<T>& pu) noexcept(see below);
57 typedef remove_reference_t<decltype(*declval<T&>())> element_type;
59 // [propagate_const.ctor], constructors
60 constexpr propagate_const() = default;
61 propagate_const(const propagate_const& p) = delete;
62 constexpr propagate_const(propagate_const&& p) = default;
63 template <class U> EXPLICIT constexpr propagate_const(propagate_const<_Up>&& pu); // see below
64 template <class U> EXPLICIT constexpr propagate_const(U&& u); // see below
66 // [propagate_const.assignment], assignment
67 propagate_const& operator=(const propagate_const& p) = delete;
68 constexpr propagate_const& operator=(propagate_const&& p) = default;
69 template <class U> constexpr propagate_const& operator=(propagate_const<_Up>&& pu);
70 template <class U> constexpr propagate_const& operator=(U&& u); // see below
72 // [propagate_const.const_observers], const observers
73 explicit constexpr operator bool() const;
74 constexpr const element_type* operator->() const;
75 constexpr operator const element_type*() const; // Not always defined
76 constexpr const element_type& operator*() const;
77 constexpr const element_type* get() const;
79 // [propagate_const.non_const_observers], non-const observers
80 constexpr element_type* operator->();
81 constexpr operator element_type*(); // Not always defined
82 constexpr element_type& operator*();
83 constexpr element_type* get();
85 // [propagate_const.modifiers], modifiers
86 constexpr void swap(propagate_const& pt) noexcept(see below)
89 T t_; // exposition only
92 } // namespace fundamentals_v2
93 } // namespace experimental
95 // [propagate_const.hash], hash support
96 template <class T> struct hash<experimental::propagate_const<T>>;
98 // [propagate_const.comparison_function_objects], comparison function objects
99 template <class T> struct equal_to<experimental::propagate_const<T>>;
100 template <class T> struct not_equal_to<experimental::propagate_const<T>>;
101 template <class T> struct less<experimental::propagate_const<T>>;
102 template <class T> struct greater<experimental::propagate_const<T>>;
103 template <class T> struct less_equal<experimental::propagate_const<T>>;
104 template <class T> struct greater_equal<experimental::propagate_const<T>>;
110 #include <__assert> // all public C++ headers provide the assertion handler
111 #include <__functional/operations.h>
112 #include <__fwd/hash.h>
113 #include <__type_traits/conditional.h>
114 #include <__type_traits/decay.h>
115 #include <__type_traits/enable_if.h>
116 #include <__type_traits/is_array.h>
117 #include <__type_traits/is_constructible.h>
118 #include <__type_traits/is_convertible.h>
119 #include <__type_traits/is_function.h>
120 #include <__type_traits/is_pointer.h>
121 #include <__type_traits/is_reference.h>
122 #include <__type_traits/is_same.h>
123 #include <__type_traits/is_swappable.h>
124 #include <__type_traits/remove_cv.h>
125 #include <__type_traits/remove_pointer.h>
126 #include <__type_traits/remove_reference.h>
127 #include <__utility/declval.h>
128 #include <__utility/forward.h>
129 #include <__utility/move.h>
130 #include <__utility/swap.h>
132 #include <experimental/__config>
134 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
135 # pragma GCC system_header
139 #include <__undef_macros>
141 #if _LIBCPP_STD_VER >= 14
143 _LIBCPP_BEGIN_NAMESPACE_LFTS_V2
146 class propagate_const;
149 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const _Up& get_underlying(const propagate_const<_Up>& __pu) _NOEXCEPT;
152 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Up& get_underlying(propagate_const<_Up>& __pu) _NOEXCEPT;
155 class propagate_const {
157 typedef remove_reference_t<decltype(*std::declval<_Tp&>())> element_type;
159 static_assert(!is_array<_Tp>::value, "Instantiation of propagate_const with an array type is ill-formed.");
160 static_assert(!is_reference<_Tp>::value, "Instantiation of propagate_const with a reference type is ill-formed.");
161 static_assert(!(is_pointer<_Tp>::value && is_function<__remove_pointer_t<_Tp> >::value),
162 "Instantiation of propagate_const with a function-pointer type is ill-formed.");
163 static_assert(!(is_pointer<_Tp>::value && is_same<__remove_cv_t<__remove_pointer_t<_Tp> >, void>::value),
164 "Instantiation of propagate_const with a pointer to (possibly cv-qualified) void is ill-formed.");
168 static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR element_type* __get_pointer(_Up* __u) {
173 static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR element_type* __get_pointer(_Up& __u) {
174 return __get_pointer(__u.get());
178 static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const element_type* __get_pointer(const _Up* __u) {
183 static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const element_type* __get_pointer(const _Up& __u) {
184 return __get_pointer(__u.get());
188 struct __is_propagate_const : false_type {};
191 struct __is_propagate_const<propagate_const<_Up>> : true_type {};
197 friend _LIBCPP_CONSTEXPR const _Up&
198 experimental::fundamentals_v2::get_underlying(const propagate_const<_Up>& __pu) _NOEXCEPT;
200 friend _LIBCPP_CONSTEXPR _Up& experimental::fundamentals_v2::get_underlying(propagate_const<_Up>& __pu) _NOEXCEPT;
202 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR propagate_const() = default;
204 propagate_const(const propagate_const&) = delete;
206 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR propagate_const(propagate_const&&) = default;
209 enable_if_t<!is_convertible<_Up, _Tp>::value && is_constructible<_Tp, _Up&&>::value, bool> = true>
210 explicit _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR propagate_const(propagate_const<_Up>&& __pu)
211 : __t_(std::move(experimental::get_underlying(__pu))) {}
214 enable_if_t<is_convertible<_Up&&, _Tp>::value && is_constructible<_Tp, _Up&&>::value, bool> = false>
215 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR propagate_const(propagate_const<_Up>&& __pu)
216 : __t_(std::move(experimental::get_underlying(__pu))) {}
219 enable_if_t<!is_convertible<_Up&&, _Tp>::value && is_constructible<_Tp, _Up&&>::value &&
220 !__is_propagate_const<decay_t<_Up>>::value,
222 explicit _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR propagate_const(_Up&& __u) : __t_(std::forward<_Up>(__u)) {}
225 enable_if_t<is_convertible<_Up&&, _Tp>::value && is_constructible<_Tp, _Up&&>::value &&
226 !__is_propagate_const<decay_t<_Up>>::value,
228 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR propagate_const(_Up&& __u) : __t_(std::forward<_Up>(__u)) {}
230 propagate_const& operator=(const propagate_const&) = delete;
232 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR propagate_const& operator=(propagate_const&&) = default;
235 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR propagate_const& operator=(propagate_const<_Up>&& __pu) {
236 __t_ = std::move(experimental::get_underlying(__pu));
240 template <class _Up, class _Vp = enable_if_t<!__is_propagate_const<decay_t<_Up>>::value>>
241 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR propagate_const& operator=(_Up&& __u) {
242 __t_ = std::forward<_Up>(__u);
246 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const element_type* get() const { return __get_pointer(__t_); }
248 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR element_type* get() { return __get_pointer(__t_); }
250 _LIBCPP_HIDE_FROM_ABI explicit _LIBCPP_CONSTEXPR operator bool() const { return get() != nullptr; }
252 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const element_type* operator->() const { return get(); }
254 template <class _Dummy = _Tp, class _Up = enable_if_t<is_convertible< const _Dummy, const element_type*>::value>>
255 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR operator const element_type*() const {
259 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const element_type& operator*() const { return *get(); }
261 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR element_type* operator->() { return get(); }
263 template <class _Dummy = _Tp, class _Up = enable_if_t< is_convertible<_Dummy, element_type*>::value>>
264 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR operator element_type*() {
268 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR element_type& operator*() { return *get(); }
270 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR void swap(propagate_const& __pt)
271 _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value) {
273 swap(__t_, __pt.__t_);
278 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator==(const propagate_const<_Tp>& __pt, nullptr_t) {
279 return experimental::get_underlying(__pt) == nullptr;
283 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator==(nullptr_t, const propagate_const<_Tp>& __pt) {
284 return nullptr == experimental::get_underlying(__pt);
288 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator!=(const propagate_const<_Tp>& __pt, nullptr_t) {
289 return experimental::get_underlying(__pt) != nullptr;
293 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator!=(nullptr_t, const propagate_const<_Tp>& __pt) {
294 return nullptr != experimental::get_underlying(__pt);
297 template <class _Tp, class _Up>
298 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
299 operator==(const propagate_const<_Tp>& __pt, const propagate_const<_Up>& __pu) {
300 return experimental::get_underlying(__pt) == experimental::get_underlying(__pu);
303 template <class _Tp, class _Up>
304 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
305 operator!=(const propagate_const<_Tp>& __pt, const propagate_const<_Up>& __pu) {
306 return experimental::get_underlying(__pt) != experimental::get_underlying(__pu);
309 template <class _Tp, class _Up>
310 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
311 operator<(const propagate_const<_Tp>& __pt, const propagate_const<_Up>& __pu) {
312 return experimental::get_underlying(__pt) < experimental::get_underlying(__pu);
315 template <class _Tp, class _Up>
316 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
317 operator>(const propagate_const<_Tp>& __pt, const propagate_const<_Up>& __pu) {
318 return experimental::get_underlying(__pt) > experimental::get_underlying(__pu);
321 template <class _Tp, class _Up>
322 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
323 operator<=(const propagate_const<_Tp>& __pt, const propagate_const<_Up>& __pu) {
324 return experimental::get_underlying(__pt) <= experimental::get_underlying(__pu);
327 template <class _Tp, class _Up>
328 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool
329 operator>=(const propagate_const<_Tp>& __pt, const propagate_const<_Up>& __pu) {
330 return experimental::get_underlying(__pt) >= experimental::get_underlying(__pu);
333 template <class _Tp, class _Up>
334 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator==(const propagate_const<_Tp>& __pt, const _Up& __u) {
335 return experimental::get_underlying(__pt) == __u;
338 template <class _Tp, class _Up>
339 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator!=(const propagate_const<_Tp>& __pt, const _Up& __u) {
340 return experimental::get_underlying(__pt) != __u;
343 template <class _Tp, class _Up>
344 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator<(const propagate_const<_Tp>& __pt, const _Up& __u) {
345 return experimental::get_underlying(__pt) < __u;
348 template <class _Tp, class _Up>
349 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator>(const propagate_const<_Tp>& __pt, const _Up& __u) {
350 return experimental::get_underlying(__pt) > __u;
353 template <class _Tp, class _Up>
354 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator<=(const propagate_const<_Tp>& __pt, const _Up& __u) {
355 return experimental::get_underlying(__pt) <= __u;
358 template <class _Tp, class _Up>
359 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator>=(const propagate_const<_Tp>& __pt, const _Up& __u) {
360 return experimental::get_underlying(__pt) >= __u;
363 template <class _Tp, class _Up>
364 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator==(const _Tp& __t, const propagate_const<_Up>& __pu) {
365 return __t == experimental::get_underlying(__pu);
368 template <class _Tp, class _Up>
369 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator!=(const _Tp& __t, const propagate_const<_Up>& __pu) {
370 return __t != experimental::get_underlying(__pu);
373 template <class _Tp, class _Up>
374 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator<(const _Tp& __t, const propagate_const<_Up>& __pu) {
375 return __t < experimental::get_underlying(__pu);
378 template <class _Tp, class _Up>
379 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator>(const _Tp& __t, const propagate_const<_Up>& __pu) {
380 return __t > experimental::get_underlying(__pu);
383 template <class _Tp, class _Up>
384 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator<=(const _Tp& __t, const propagate_const<_Up>& __pu) {
385 return __t <= experimental::get_underlying(__pu);
388 template <class _Tp, class _Up>
389 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator>=(const _Tp& __t, const propagate_const<_Up>& __pu) {
390 return __t >= experimental::get_underlying(__pu);
394 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR void swap(propagate_const<_Tp>& __pc1, propagate_const<_Tp>& __pc2)
395 _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value) {
400 _LIBCPP_CONSTEXPR const _Tp& get_underlying(const propagate_const<_Tp>& __pt) _NOEXCEPT {
405 _LIBCPP_CONSTEXPR _Tp& get_underlying(propagate_const<_Tp>& __pt) _NOEXCEPT {
409 _LIBCPP_END_NAMESPACE_LFTS_V2
411 _LIBCPP_BEGIN_NAMESPACE_STD
414 struct hash<experimental::propagate_const<_Tp>> {
415 typedef size_t result_type;
416 typedef experimental::propagate_const<_Tp> argument_type;
418 _LIBCPP_HIDE_FROM_ABI size_t operator()(const experimental::propagate_const<_Tp>& __pc1) const {
419 return std::hash<_Tp>()(experimental::get_underlying(__pc1));
424 struct equal_to<experimental::propagate_const<_Tp>> {
425 typedef experimental::propagate_const<_Tp> first_argument_type;
426 typedef experimental::propagate_const<_Tp> second_argument_type;
428 _LIBCPP_HIDE_FROM_ABI bool
429 operator()(const experimental::propagate_const<_Tp>& __pc1, const experimental::propagate_const<_Tp>& __pc2) const {
430 return std::equal_to<_Tp>()(experimental::get_underlying(__pc1), experimental::get_underlying(__pc2));
435 struct not_equal_to<experimental::propagate_const<_Tp>> {
436 typedef experimental::propagate_const<_Tp> first_argument_type;
437 typedef experimental::propagate_const<_Tp> second_argument_type;
439 _LIBCPP_HIDE_FROM_ABI bool
440 operator()(const experimental::propagate_const<_Tp>& __pc1, const experimental::propagate_const<_Tp>& __pc2) const {
441 return std::not_equal_to<_Tp>()(experimental::get_underlying(__pc1), experimental::get_underlying(__pc2));
446 struct less<experimental::propagate_const<_Tp>> {
447 typedef experimental::propagate_const<_Tp> first_argument_type;
448 typedef experimental::propagate_const<_Tp> second_argument_type;
450 _LIBCPP_HIDE_FROM_ABI bool
451 operator()(const experimental::propagate_const<_Tp>& __pc1, const experimental::propagate_const<_Tp>& __pc2) const {
452 return std::less<_Tp>()(experimental::get_underlying(__pc1), experimental::get_underlying(__pc2));
457 struct greater<experimental::propagate_const<_Tp>> {
458 typedef experimental::propagate_const<_Tp> first_argument_type;
459 typedef experimental::propagate_const<_Tp> second_argument_type;
461 _LIBCPP_HIDE_FROM_ABI bool
462 operator()(const experimental::propagate_const<_Tp>& __pc1, const experimental::propagate_const<_Tp>& __pc2) const {
463 return std::greater<_Tp>()(experimental::get_underlying(__pc1), experimental::get_underlying(__pc2));
468 struct less_equal<experimental::propagate_const<_Tp>> {
469 typedef experimental::propagate_const<_Tp> first_argument_type;
470 typedef experimental::propagate_const<_Tp> second_argument_type;
472 _LIBCPP_HIDE_FROM_ABI bool
473 operator()(const experimental::propagate_const<_Tp>& __pc1, const experimental::propagate_const<_Tp>& __pc2) const {
474 return std::less_equal<_Tp>()(experimental::get_underlying(__pc1), experimental::get_underlying(__pc2));
479 struct greater_equal<experimental::propagate_const<_Tp>> {
480 typedef experimental::propagate_const<_Tp> first_argument_type;
481 typedef experimental::propagate_const<_Tp> second_argument_type;
483 _LIBCPP_HIDE_FROM_ABI bool
484 operator()(const experimental::propagate_const<_Tp>& __pc1, const experimental::propagate_const<_Tp>& __pc2) const {
485 return std::greater_equal<_Tp>()(experimental::get_underlying(__pc1), experimental::get_underlying(__pc2));
489 _LIBCPP_END_NAMESPACE_STD
491 #endif // _LIBCPP_STD_VER >= 14
495 #if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
496 # include <type_traits>
499 #endif // _LIBCPP_EXPERIMENTAL_PROPAGATE_CONST