master
  1// -*- C++ -*-
  2//===----------------------------------------------------------------------===//
  3//
  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
  7//
  8//===----------------------------------------------------------------------===//
  9
 10#ifndef _LIBCPP___BIT_REFERENCE
 11#define _LIBCPP___BIT_REFERENCE
 12
 13#include <__algorithm/comp.h>
 14#include <__algorithm/copy.h>
 15#include <__algorithm/copy_backward.h>
 16#include <__algorithm/copy_n.h>
 17#include <__algorithm/equal.h>
 18#include <__algorithm/min.h>
 19#include <__algorithm/rotate.h>
 20#include <__algorithm/swap_ranges.h>
 21#include <__assert>
 22#include <__bit/countr.h>
 23#include <__compare/ordering.h>
 24#include <__config>
 25#include <__cstddef/ptrdiff_t.h>
 26#include <__cstddef/size_t.h>
 27#include <__functional/identity.h>
 28#include <__fwd/bit_reference.h>
 29#include <__iterator/iterator_traits.h>
 30#include <__memory/construct_at.h>
 31#include <__memory/pointer_traits.h>
 32#include <__type_traits/conditional.h>
 33#include <__type_traits/desugars_to.h>
 34#include <__type_traits/enable_if.h>
 35#include <__type_traits/is_constant_evaluated.h>
 36#include <__type_traits/is_same.h>
 37#include <__type_traits/is_unsigned.h>
 38#include <__type_traits/void_t.h>
 39#include <__utility/pair.h>
 40#include <__utility/swap.h>
 41#include <climits>
 42
 43#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 44#  pragma GCC system_header
 45#endif
 46
 47_LIBCPP_PUSH_MACROS
 48#include <__undef_macros>
 49
 50_LIBCPP_BEGIN_NAMESPACE_STD
 51
 52template <class _Cp>
 53class __bit_const_reference;
 54
 55template <class _Tp>
 56struct __has_storage_type {
 57  static const bool value = false;
 58};
 59
 60template <class, class>
 61struct __size_difference_type_traits {
 62  using difference_type = ptrdiff_t;
 63  using size_type       = size_t;
 64};
 65
 66template <class _Cp>
 67struct __size_difference_type_traits<_Cp, __void_t<typename _Cp::difference_type, typename _Cp::size_type> > {
 68  using difference_type = typename _Cp::difference_type;
 69  using size_type       = typename _Cp::size_type;
 70};
 71
 72// The `__x_mask` functions are designed to work exclusively with any unsigned `_StorageType`s, including small
 73// integral types such as unsigned char/short, `uint8_t`, and `uint16_t`. To prevent undefined behavior or
 74// ambiguities due to integral promotions for the small integral types, all intermediate bitwise operations are
 75// explicitly cast back to the unsigned `_StorageType`.
 76
 77// Creates a mask of type `_StorageType` with a specified number of leading zeros (__clz) and sets all remaining
 78// bits to one.
 79template <class _StorageType>
 80_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _StorageType __trailing_mask(unsigned __clz) {
 81  static_assert(is_unsigned<_StorageType>::value, "__trailing_mask only works with unsigned types");
 82  return static_cast<_StorageType>(~static_cast<_StorageType>(0)) >> __clz;
 83}
 84
 85// Creates a mask of type `_StorageType` with a specified number of trailing zeros (__ctz) and sets all remaining
 86// bits to one.
 87template <class _StorageType>
 88_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _StorageType __leading_mask(unsigned __ctz) {
 89  static_assert(is_unsigned<_StorageType>::value, "__leading_mask only works with unsigned types");
 90  return static_cast<_StorageType>(~static_cast<_StorageType>(0)) << __ctz;
 91}
 92
 93// Creates a mask of type `_StorageType` with a specified number of leading zeros (__clz), a specified number of
 94// trailing zeros (__ctz), and sets all bits in between to one.
 95template <class _StorageType>
 96_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _StorageType __middle_mask(unsigned __clz, unsigned __ctz) {
 97  static_assert(is_unsigned<_StorageType>::value, "__middle_mask only works with unsigned types");
 98  return std::__leading_mask<_StorageType>(__ctz) & std::__trailing_mask<_StorageType>(__clz);
 99}
100
101// This function is designed to operate correctly even for smaller integral types like `uint8_t`, `uint16_t`,
102// or `unsigned short`.
103// See https://github.com/llvm/llvm-project/pull/122410.
104template <class _StoragePointer>
105_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
106__fill_masked_range(_StoragePointer __word, unsigned __clz, unsigned __ctz, bool __fill_val) {
107  static_assert(is_unsigned<typename pointer_traits<_StoragePointer>::element_type>::value,
108                "__fill_masked_range must be called with unsigned type");
109  using _StorageType = typename pointer_traits<_StoragePointer>::element_type;
110  _LIBCPP_ASSERT_VALID_INPUT_RANGE(
111      __ctz + __clz < sizeof(_StorageType) * CHAR_BIT, "__fill_masked_range called with invalid range");
112  _StorageType __m = std::__middle_mask<_StorageType>(__clz, __ctz);
113  if (__fill_val)
114    *__word |= __m;
115  else
116    *__word &= ~__m;
117}
118
119template <class _Cp, bool = __has_storage_type<_Cp>::value>
120class __bit_reference {
121  using __storage_type _LIBCPP_NODEBUG    = typename _Cp::__storage_type;
122  using __storage_pointer _LIBCPP_NODEBUG = typename _Cp::__storage_pointer;
123
124  __storage_pointer __seg_;
125  __storage_type __mask_;
126
127  friend typename _Cp::__self;
128
129  friend class __bit_const_reference<_Cp>;
130  friend class __bit_iterator<_Cp, false>;
131
132public:
133  using __container _LIBCPP_NODEBUG = typename _Cp::__self;
134
135  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_reference(const __bit_reference&) = default;
136
137  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 operator bool() const _NOEXCEPT {
138    return static_cast<bool>(*__seg_ & __mask_);
139  }
140  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool operator~() const _NOEXCEPT {
141    return !static_cast<bool>(*this);
142  }
143
144  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_reference& operator=(bool __x) _NOEXCEPT {
145    if (__x)
146      *__seg_ |= __mask_;
147    else
148      *__seg_ &= ~__mask_;
149    return *this;
150  }
151
152#if _LIBCPP_STD_VER >= 23
153  _LIBCPP_HIDE_FROM_ABI constexpr const __bit_reference& operator=(bool __x) const noexcept {
154    if (__x)
155      *__seg_ |= __mask_;
156    else
157      *__seg_ &= ~__mask_;
158    return *this;
159  }
160#endif
161
162  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_reference& operator=(const __bit_reference& __x) _NOEXCEPT {
163    return operator=(static_cast<bool>(__x));
164  }
165
166  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void flip() _NOEXCEPT { *__seg_ ^= __mask_; }
167  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator<_Cp, false> operator&() const _NOEXCEPT {
168    return __bit_iterator<_Cp, false>(__seg_, static_cast<unsigned>(std::__countr_zero(__mask_)));
169  }
170
171private:
172  _LIBCPP_HIDE_FROM_ABI
173  _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit __bit_reference(__storage_pointer __s, __storage_type __m) _NOEXCEPT
174      : __seg_(__s),
175        __mask_(__m) {}
176};
177
178template <class _Cp>
179class __bit_reference<_Cp, false> {};
180
181template <class _Cp>
182inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
183swap(__bit_reference<_Cp> __x, __bit_reference<_Cp> __y) _NOEXCEPT {
184  bool __t = __x;
185  __x      = __y;
186  __y      = __t;
187}
188
189template <class _Cp, class _Dp>
190inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
191swap(__bit_reference<_Cp> __x, __bit_reference<_Dp> __y) _NOEXCEPT {
192  bool __t = __x;
193  __x      = __y;
194  __y      = __t;
195}
196
197template <class _Cp>
198inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(__bit_reference<_Cp> __x, bool& __y) _NOEXCEPT {
199  bool __t = __x;
200  __x      = __y;
201  __y      = __t;
202}
203
204template <class _Cp>
205inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(bool& __x, __bit_reference<_Cp> __y) _NOEXCEPT {
206  bool __t = __x;
207  __x      = __y;
208  __y      = __t;
209}
210
211template <class _Cp>
212class __bit_const_reference {
213  using __storage_type _LIBCPP_NODEBUG    = typename _Cp::__storage_type;
214  using __storage_pointer _LIBCPP_NODEBUG = typename _Cp::__const_storage_pointer;
215
216  __storage_pointer __seg_;
217  __storage_type __mask_;
218
219  friend typename _Cp::__self;
220  friend class __bit_iterator<_Cp, true>;
221
222public:
223  using __container _LIBCPP_NODEBUG = typename _Cp::__self;
224
225  _LIBCPP_HIDE_FROM_ABI __bit_const_reference(const __bit_const_reference&) = default;
226  __bit_const_reference& operator=(const __bit_const_reference&)            = delete;
227
228  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_const_reference(const __bit_reference<_Cp>& __x) _NOEXCEPT
229      : __seg_(__x.__seg_),
230        __mask_(__x.__mask_) {}
231
232  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR operator bool() const _NOEXCEPT {
233    return static_cast<bool>(*__seg_ & __mask_);
234  }
235
236  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator<_Cp, true> operator&() const _NOEXCEPT {
237    return __bit_iterator<_Cp, true>(__seg_, static_cast<unsigned>(std::__countr_zero(__mask_)));
238  }
239
240private:
241  _LIBCPP_HIDE_FROM_ABI
242  _LIBCPP_CONSTEXPR explicit __bit_const_reference(__storage_pointer __s, __storage_type __m) _NOEXCEPT
243      : __seg_(__s),
244        __mask_(__m) {}
245};
246
247template <class _Cp>
248struct __bit_array {
249  using difference_type _LIBCPP_NODEBUG   = typename __size_difference_type_traits<_Cp>::difference_type;
250  using __storage_type _LIBCPP_NODEBUG    = typename _Cp::__storage_type;
251  using __storage_pointer _LIBCPP_NODEBUG = typename _Cp::__storage_pointer;
252  using iterator _LIBCPP_NODEBUG          = typename _Cp::iterator;
253
254  static const unsigned __bits_per_word = _Cp::__bits_per_word;
255  static const unsigned _Np             = 4;
256
257  difference_type __size_;
258  __storage_type __word_[_Np];
259
260  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static difference_type capacity() {
261    return static_cast<difference_type>(_Np * __bits_per_word);
262  }
263  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit __bit_array(difference_type __s) : __size_(__s) {
264    if (__libcpp_is_constant_evaluated()) {
265      for (size_t __i = 0; __i != __bit_array<_Cp>::_Np; ++__i)
266        std::__construct_at(__word_ + __i, 0);
267    }
268  }
269  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator begin() {
270    return iterator(pointer_traits<__storage_pointer>::pointer_to(__word_[0]), 0);
271  }
272  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator end() {
273    return iterator(pointer_traits<__storage_pointer>::pointer_to(__word_[0]) + __size_ / __bits_per_word,
274                    static_cast<unsigned>(__size_ % __bits_per_word));
275  }
276};
277
278template <class _Cp, bool _IsConst, typename _Cp::__storage_type>
279class __bit_iterator {
280public:
281  using difference_type = typename __size_difference_type_traits<_Cp>::difference_type;
282  using value_type      = bool;
283  using pointer         = __bit_iterator;
284#ifndef _LIBCPP_ABI_BITSET_VECTOR_BOOL_CONST_SUBSCRIPT_RETURN_BOOL
285  using reference = __conditional_t<_IsConst, __bit_const_reference<_Cp>, __bit_reference<_Cp> >;
286#else
287  using reference = __conditional_t<_IsConst, bool, __bit_reference<_Cp> >;
288#endif
289  using iterator_category = random_access_iterator_tag;
290
291private:
292  using __storage_type _LIBCPP_NODEBUG = typename _Cp::__storage_type;
293  using __storage_pointer _LIBCPP_NODEBUG =
294      __conditional_t<_IsConst, typename _Cp::__const_storage_pointer, typename _Cp::__storage_pointer>;
295
296  static const unsigned __bits_per_word = _Cp::__bits_per_word;
297
298  __storage_pointer __seg_;
299  unsigned __ctz_;
300
301public:
302  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator() _NOEXCEPT
303#if _LIBCPP_STD_VER >= 14
304      : __seg_(nullptr),
305        __ctz_(0)
306#endif
307  {
308  }
309
310  // When _IsConst=false, this is the copy constructor.
311  // It is non-trivial. Making it trivial would break ABI.
312  // When _IsConst=true, this is a converting constructor;
313  // the copy and move constructors are implicitly generated
314  // and trivial.
315  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator(const __bit_iterator<_Cp, false>& __it) _NOEXCEPT
316      : __seg_(__it.__seg_),
317        __ctz_(__it.__ctz_) {}
318
319  // When _IsConst=false, we have a user-provided copy constructor,
320  // so we must also provide a copy assignment operator because
321  // the implicit generation of a defaulted one is deprecated.
322  // When _IsConst=true, the assignment operators are
323  // implicitly generated and trivial.
324  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator&
325  operator=(const _If<_IsConst, struct __private_nat, __bit_iterator>& __it) {
326    __seg_ = __it.__seg_;
327    __ctz_ = __it.__ctz_;
328    return *this;
329  }
330
331  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference operator*() const _NOEXCEPT {
332    _LIBCPP_ASSERT_INTERNAL(__ctz_ < __bits_per_word, "Dereferencing an invalid __bit_iterator.");
333    return __conditional_t<_IsConst, __bit_const_reference<_Cp>, __bit_reference<_Cp> >(
334        __seg_, __storage_type(1) << __ctz_);
335  }
336
337  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator& operator++() {
338    if (__ctz_ != __bits_per_word - 1)
339      ++__ctz_;
340    else {
341      __ctz_ = 0;
342      ++__seg_;
343    }
344    return *this;
345  }
346
347  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator operator++(int) {
348    __bit_iterator __tmp = *this;
349    ++(*this);
350    return __tmp;
351  }
352
353  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator& operator--() {
354    if (__ctz_ != 0)
355      --__ctz_;
356    else {
357      __ctz_ = __bits_per_word - 1;
358      --__seg_;
359    }
360    return *this;
361  }
362
363  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator operator--(int) {
364    __bit_iterator __tmp = *this;
365    --(*this);
366    return __tmp;
367  }
368
369  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator& operator+=(difference_type __n) {
370    if (__n >= 0)
371      __seg_ += (__n + __ctz_) / __bits_per_word;
372    else
373      __seg_ += static_cast<difference_type>(__n - __bits_per_word + __ctz_ + 1) /
374                static_cast<difference_type>(__bits_per_word);
375    __n &= (__bits_per_word - 1);
376    __ctz_ = static_cast<unsigned>((__n + __ctz_) % __bits_per_word);
377    return *this;
378  }
379
380  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator& operator-=(difference_type __n) {
381    return *this += -__n;
382  }
383
384  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator operator+(difference_type __n) const {
385    __bit_iterator __t(*this);
386    __t += __n;
387    return __t;
388  }
389
390  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator operator-(difference_type __n) const {
391    __bit_iterator __t(*this);
392    __t -= __n;
393    return __t;
394  }
395
396  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator
397  operator+(difference_type __n, const __bit_iterator& __it) {
398    return __it + __n;
399  }
400
401  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 friend difference_type
402  operator-(const __bit_iterator& __x, const __bit_iterator& __y) {
403    return (__x.__seg_ - __y.__seg_) * __bits_per_word + __x.__ctz_ - __y.__ctz_;
404  }
405
406  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference operator[](difference_type __n) const {
407    return *(*this + __n);
408  }
409
410  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 friend bool
411  operator==(const __bit_iterator& __x, const __bit_iterator& __y) {
412    return __x.__seg_ == __y.__seg_ && __x.__ctz_ == __y.__ctz_;
413  }
414
415#if _LIBCPP_STD_VER <= 17
416  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 friend bool
417  operator!=(const __bit_iterator& __x, const __bit_iterator& __y) {
418    return !(__x == __y);
419  }
420
421  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 friend bool
422  operator<(const __bit_iterator& __x, const __bit_iterator& __y) {
423    return __x.__seg_ < __y.__seg_ || (__x.__seg_ == __y.__seg_ && __x.__ctz_ < __y.__ctz_);
424  }
425
426  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 friend bool
427  operator>(const __bit_iterator& __x, const __bit_iterator& __y) {
428    return __y < __x;
429  }
430
431  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 friend bool
432  operator<=(const __bit_iterator& __x, const __bit_iterator& __y) {
433    return !(__y < __x);
434  }
435
436  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 friend bool
437  operator>=(const __bit_iterator& __x, const __bit_iterator& __y) {
438    return !(__x < __y);
439  }
440#else  // _LIBCPP_STD_VER <= 17
441  _LIBCPP_HIDE_FROM_ABI constexpr friend strong_ordering
442  operator<=>(const __bit_iterator& __x, const __bit_iterator& __y) {
443    if (__x.__seg_ < __y.__seg_)
444      return strong_ordering::less;
445
446    if (__x.__seg_ == __y.__seg_)
447      return __x.__ctz_ <=> __y.__ctz_;
448
449    return strong_ordering::greater;
450  }
451#endif // _LIBCPP_STD_VER <= 17
452
453private:
454  _LIBCPP_HIDE_FROM_ABI
455  _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit __bit_iterator(__storage_pointer __s, unsigned __ctz) _NOEXCEPT
456      : __seg_(__s),
457        __ctz_(__ctz) {
458    _LIBCPP_ASSERT_INTERNAL(
459        __ctz_ < __bits_per_word, "__bit_iterator initialized with an invalid number of trailing zeros.");
460  }
461
462  friend typename _Cp::__self;
463
464  friend class __bit_reference<_Cp>;
465  friend class __bit_const_reference<_Cp>;
466  friend class __bit_iterator<_Cp, true>;
467  template <class _Dp>
468  friend struct __bit_array;
469
470  template <bool _FillVal, class _Dp>
471  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend void
472  __fill_n_bool(__bit_iterator<_Dp, false> __first, typename __size_difference_type_traits<_Dp>::size_type __n);
473
474  template <class _Dp, bool _IC>
475  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator<_Dp, false> __copy_aligned(
476      __bit_iterator<_Dp, _IC> __first, __bit_iterator<_Dp, _IC> __last, __bit_iterator<_Dp, false> __result);
477  template <class _Dp, bool _IC>
478  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator<_Dp, false> __copy_unaligned(
479      __bit_iterator<_Dp, _IC> __first, __bit_iterator<_Dp, _IC> __last, __bit_iterator<_Dp, false> __result);
480  template <class _Dp, bool _IC>
481  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend pair<__bit_iterator<_Dp, _IC>, __bit_iterator<_Dp, false> >
482  __copy_impl::operator()(
483      __bit_iterator<_Dp, _IC> __first, __bit_iterator<_Dp, _IC> __last, __bit_iterator<_Dp, false> __result) const;
484  template <class _Dp, bool _IC>
485  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator<_Dp, false> __copy_backward_aligned(
486      __bit_iterator<_Dp, _IC> __first, __bit_iterator<_Dp, _IC> __last, __bit_iterator<_Dp, false> __result);
487  template <class _Dp, bool _IC>
488  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator<_Dp, false> __copy_backward_unaligned(
489      __bit_iterator<_Dp, _IC> __first, __bit_iterator<_Dp, _IC> __last, __bit_iterator<_Dp, false> __result);
490  template <class _AlgPolicy>
491  friend struct __copy_backward_impl;
492  template <class _Cl, class _Cr>
493  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator<_Cr, false>
494      __swap_ranges_aligned(__bit_iterator<_Cl, false>, __bit_iterator<_Cl, false>, __bit_iterator<_Cr, false>);
495  template <class _Cl, class _Cr>
496  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator<_Cr, false>
497      __swap_ranges_unaligned(__bit_iterator<_Cl, false>, __bit_iterator<_Cl, false>, __bit_iterator<_Cr, false>);
498  template <class, class _Cl, class _Cr>
499  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend pair<__bit_iterator<_Cl, false>, __bit_iterator<_Cr, false> >
500      __swap_ranges(__bit_iterator<_Cl, false>, __bit_iterator<_Cl, false>, __bit_iterator<_Cr, false>);
501  template <class, class _Dp>
502  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend pair<__bit_iterator<_Dp, false>, __bit_iterator<_Dp, false> >
503      __rotate(__bit_iterator<_Dp, false>, __bit_iterator<_Dp, false>, __bit_iterator<_Dp, false>);
504  template <class _Dp, bool _IsConst1, bool _IsConst2>
505  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend bool
506      __equal_aligned(__bit_iterator<_Dp, _IsConst1>, __bit_iterator<_Dp, _IsConst1>, __bit_iterator<_Dp, _IsConst2>);
507  template <class _Dp, bool _IsConst1, bool _IsConst2>
508  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend bool
509      __equal_unaligned(__bit_iterator<_Dp, _IsConst1>, __bit_iterator<_Dp, _IsConst1>, __bit_iterator<_Dp, _IsConst2>);
510  template <class _Dp,
511            bool _IsConst1,
512            bool _IsConst2,
513            class _BinaryPredicate,
514            __enable_if_t<__desugars_to_v<__equal_tag, _BinaryPredicate, bool, bool>, int> >
515  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 friend bool __equal_iter_impl(
516      __bit_iterator<_Dp, _IsConst1>, __bit_iterator<_Dp, _IsConst1>, __bit_iterator<_Dp, _IsConst2>, _BinaryPredicate);
517  template <class _Dp,
518            bool _IsConst1,
519            bool _IsConst2,
520            class _Pred,
521            class _Proj1,
522            class _Proj2,
523            __enable_if_t<__desugars_to_v<__equal_tag, _Pred, bool, bool> && __is_identity<_Proj1>::value &&
524                              __is_identity<_Proj2>::value,
525                          int> >
526  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 friend bool __equal_impl(
527      __bit_iterator<_Dp, _IsConst1> __first1,
528      __bit_iterator<_Dp, _IsConst1> __last1,
529      __bit_iterator<_Dp, _IsConst2> __first2,
530      __bit_iterator<_Dp, _IsConst2>,
531      _Pred&,
532      _Proj1&,
533      _Proj2&);
534  template <bool _ToFind, class _Dp, bool _IC>
535  _LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator<_Dp, _IC>
536      __find_bool(__bit_iterator<_Dp, _IC>, typename __size_difference_type_traits<_Dp>::size_type);
537  template <bool _ToCount, class _Dp, bool _IC>
538  friend typename __bit_iterator<_Dp, _IC>::difference_type _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
539  __count_bool(__bit_iterator<_Dp, _IC>, typename __size_difference_type_traits<_Dp>::size_type);
540};
541
542_LIBCPP_END_NAMESPACE_STD
543
544_LIBCPP_POP_MACROS
545
546#endif // _LIBCPP___BIT_REFERENCE