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1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP___BIT_REFERENCE
12#define _LIBCPP___BIT_REFERENCE
13
14#include <__config>
15#include <bit>
16#include <algorithm>
17
18#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19#pragma GCC system_header
20#endif
21
22_LIBCPP_PUSH_MACROS
23#include <__undef_macros>
24
25
26_LIBCPP_BEGIN_NAMESPACE_STD
27
28template <class _Cp, bool _IsConst, typename _Cp::__storage_type = 0> class __bit_iterator;
29template <class _Cp> class __bit_const_reference;
30
31template <class _Tp>
32struct __has_storage_type
33{
34    static const bool value = false;
35};
36
37template <class _Cp, bool = __has_storage_type<_Cp>::value>
38class __bit_reference
39{
40    typedef typename _Cp::__storage_type    __storage_type;
41    typedef typename _Cp::__storage_pointer __storage_pointer;
42
43    __storage_pointer __seg_;
44    __storage_type    __mask_;
45
46    friend typename _Cp::__self;
47
48    friend class __bit_const_reference<_Cp>;
49    friend class __bit_iterator<_Cp, false>;
50public:
51    _LIBCPP_INLINE_VISIBILITY operator bool() const _NOEXCEPT
52        {return static_cast<bool>(*__seg_ & __mask_);}
53    _LIBCPP_INLINE_VISIBILITY bool operator ~() const _NOEXCEPT
54        {return !static_cast<bool>(*this);}
55
56    _LIBCPP_INLINE_VISIBILITY
57    __bit_reference& operator=(bool __x) _NOEXCEPT
58    {
59        if (__x)
60            *__seg_ |= __mask_;
61        else
62            *__seg_ &= ~__mask_;
63        return *this;
64    }
65
66    _LIBCPP_INLINE_VISIBILITY
67    __bit_reference& operator=(const __bit_reference& __x) _NOEXCEPT
68        {return operator=(static_cast<bool>(__x));}
69
70    _LIBCPP_INLINE_VISIBILITY void flip() _NOEXCEPT {*__seg_ ^= __mask_;}
71    _LIBCPP_INLINE_VISIBILITY __bit_iterator<_Cp, false> operator&() const _NOEXCEPT
72        {return __bit_iterator<_Cp, false>(__seg_, static_cast<unsigned>(__ctz(__mask_)));}
73private:
74    _LIBCPP_INLINE_VISIBILITY
75    __bit_reference(__storage_pointer __s, __storage_type __m) _NOEXCEPT
76        : __seg_(__s), __mask_(__m) {}
77};
78
79template <class _Cp>
80class __bit_reference<_Cp, false>
81{
82};
83
84template <class _Cp>
85inline _LIBCPP_INLINE_VISIBILITY
86void
87swap(__bit_reference<_Cp> __x, __bit_reference<_Cp> __y) _NOEXCEPT
88{
89    bool __t = __x;
90    __x = __y;
91    __y = __t;
92}
93
94template <class _Cp, class _Dp>
95inline _LIBCPP_INLINE_VISIBILITY
96void
97swap(__bit_reference<_Cp> __x, __bit_reference<_Dp> __y) _NOEXCEPT
98{
99    bool __t = __x;
100    __x = __y;
101    __y = __t;
102}
103
104template <class _Cp>
105inline _LIBCPP_INLINE_VISIBILITY
106void
107swap(__bit_reference<_Cp> __x, bool& __y) _NOEXCEPT
108{
109    bool __t = __x;
110    __x = __y;
111    __y = __t;
112}
113
114template <class _Cp>
115inline _LIBCPP_INLINE_VISIBILITY
116void
117swap(bool& __x, __bit_reference<_Cp> __y) _NOEXCEPT
118{
119    bool __t = __x;
120    __x = __y;
121    __y = __t;
122}
123
124template <class _Cp>
125class __bit_const_reference
126{
127    typedef typename _Cp::__storage_type          __storage_type;
128    typedef typename _Cp::__const_storage_pointer __storage_pointer;
129
130    __storage_pointer        __seg_;
131    __storage_type __mask_;
132
133    friend typename _Cp::__self;
134    friend class __bit_iterator<_Cp, true>;
135public:
136    _LIBCPP_INLINE_VISIBILITY
137    __bit_const_reference(const __bit_reference<_Cp>& __x) _NOEXCEPT
138        : __seg_(__x.__seg_), __mask_(__x.__mask_) {}
139
140    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR operator bool() const _NOEXCEPT
141        {return static_cast<bool>(*__seg_ & __mask_);}
142
143    _LIBCPP_INLINE_VISIBILITY __bit_iterator<_Cp, true> operator&() const _NOEXCEPT
144        {return __bit_iterator<_Cp, true>(__seg_, static_cast<unsigned>(__ctz(__mask_)));}
145private:
146    _LIBCPP_INLINE_VISIBILITY
147    _LIBCPP_CONSTEXPR
148    __bit_const_reference(__storage_pointer __s, __storage_type __m) _NOEXCEPT
149        : __seg_(__s), __mask_(__m) {}
150
151    __bit_const_reference& operator=(const __bit_const_reference& __x);
152};
153
154// find
155
156template <class _Cp, bool _IsConst>
157__bit_iterator<_Cp, _IsConst>
158__find_bool_true(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
159{
160    typedef __bit_iterator<_Cp, _IsConst> _It;
161    typedef typename _It::__storage_type __storage_type;
162    static const int __bits_per_word = _It::__bits_per_word;
163    // do first partial word
164    if (__first.__ctz_ != 0)
165    {
166        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
167        __storage_type __dn = _VSTD::min(__clz_f, __n);
168        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
169        __storage_type __b = *__first.__seg_ & __m;
170        if (__b)
171            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__ctz(__b)));
172        if (__n == __dn)
173            return __first + __n;
174        __n -= __dn;
175        ++__first.__seg_;
176    }
177    // do middle whole words
178    for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
179        if (*__first.__seg_)
180            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__ctz(*__first.__seg_)));
181    // do last partial word
182    if (__n > 0)
183    {
184        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
185        __storage_type __b = *__first.__seg_ & __m;
186        if (__b)
187            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__ctz(__b)));
188    }
189    return _It(__first.__seg_, static_cast<unsigned>(__n));
190}
191
192template <class _Cp, bool _IsConst>
193__bit_iterator<_Cp, _IsConst>
194__find_bool_false(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
195{
196    typedef __bit_iterator<_Cp, _IsConst> _It;
197    typedef typename _It::__storage_type __storage_type;
198    const int __bits_per_word = _It::__bits_per_word;
199    // do first partial word
200    if (__first.__ctz_ != 0)
201    {
202        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
203        __storage_type __dn = _VSTD::min(__clz_f, __n);
204        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
205        __storage_type __b = ~*__first.__seg_ & __m;
206        if (__b)
207            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__ctz(__b)));
208        if (__n == __dn)
209            return __first + __n;
210        __n -= __dn;
211        ++__first.__seg_;
212    }
213    // do middle whole words
214    for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
215    {
216        __storage_type __b = ~*__first.__seg_;
217        if (__b)
218            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__ctz(__b)));
219    }
220    // do last partial word
221    if (__n > 0)
222    {
223        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
224        __storage_type __b = ~*__first.__seg_ & __m;
225        if (__b)
226            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__ctz(__b)));
227    }
228    return _It(__first.__seg_, static_cast<unsigned>(__n));
229}
230
231template <class _Cp, bool _IsConst, class _Tp>
232inline _LIBCPP_INLINE_VISIBILITY
233__bit_iterator<_Cp, _IsConst>
234find(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value_)
235{
236    if (static_cast<bool>(__value_))
237        return __find_bool_true(__first, static_cast<typename _Cp::size_type>(__last - __first));
238    return __find_bool_false(__first, static_cast<typename _Cp::size_type>(__last - __first));
239}
240
241// count
242
243template <class _Cp, bool _IsConst>
244typename __bit_iterator<_Cp, _IsConst>::difference_type
245__count_bool_true(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
246{
247    typedef __bit_iterator<_Cp, _IsConst> _It;
248    typedef typename _It::__storage_type __storage_type;
249    typedef typename _It::difference_type difference_type;
250    const int __bits_per_word = _It::__bits_per_word;
251    difference_type __r = 0;
252    // do first partial word
253    if (__first.__ctz_ != 0)
254    {
255        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
256        __storage_type __dn = _VSTD::min(__clz_f, __n);
257        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
258        __r = _VSTD::__popcount(*__first.__seg_ & __m);
259        __n -= __dn;
260        ++__first.__seg_;
261    }
262    // do middle whole words
263    for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
264        __r += _VSTD::__popcount(*__first.__seg_);
265    // do last partial word
266    if (__n > 0)
267    {
268        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
269        __r += _VSTD::__popcount(*__first.__seg_ & __m);
270    }
271    return __r;
272}
273
274template <class _Cp, bool _IsConst>
275typename __bit_iterator<_Cp, _IsConst>::difference_type
276__count_bool_false(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
277{
278    typedef __bit_iterator<_Cp, _IsConst> _It;
279    typedef typename _It::__storage_type __storage_type;
280    typedef typename _It::difference_type difference_type;
281    const int __bits_per_word = _It::__bits_per_word;
282    difference_type __r = 0;
283    // do first partial word
284    if (__first.__ctz_ != 0)
285    {
286        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
287        __storage_type __dn = _VSTD::min(__clz_f, __n);
288        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
289        __r = _VSTD::__popcount(~*__first.__seg_ & __m);
290        __n -= __dn;
291        ++__first.__seg_;
292    }
293    // do middle whole words
294    for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
295        __r += _VSTD::__popcount(~*__first.__seg_);
296    // do last partial word
297    if (__n > 0)
298    {
299        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
300        __r += _VSTD::__popcount(~*__first.__seg_ & __m);
301    }
302    return __r;
303}
304
305template <class _Cp, bool _IsConst, class _Tp>
306inline _LIBCPP_INLINE_VISIBILITY
307typename __bit_iterator<_Cp, _IsConst>::difference_type
308count(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value_)
309{
310    if (static_cast<bool>(__value_))
311        return __count_bool_true(__first, static_cast<typename _Cp::size_type>(__last - __first));
312    return __count_bool_false(__first, static_cast<typename _Cp::size_type>(__last - __first));
313}
314
315// fill_n
316
317template <class _Cp>
318void
319__fill_n_false(__bit_iterator<_Cp, false> __first, typename _Cp::size_type __n)
320{
321    typedef __bit_iterator<_Cp, false> _It;
322    typedef typename _It::__storage_type __storage_type;
323    const int __bits_per_word = _It::__bits_per_word;
324    // do first partial word
325    if (__first.__ctz_ != 0)
326    {
327        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
328        __storage_type __dn = _VSTD::min(__clz_f, __n);
329        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
330        *__first.__seg_ &= ~__m;
331        __n -= __dn;
332        ++__first.__seg_;
333    }
334    // do middle whole words
335    __storage_type __nw = __n / __bits_per_word;
336    _VSTD::memset(_VSTD::__to_raw_pointer(__first.__seg_), 0, __nw * sizeof(__storage_type));
337    __n -= __nw * __bits_per_word;
338    // do last partial word
339    if (__n > 0)
340    {
341        __first.__seg_ += __nw;
342        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
343        *__first.__seg_ &= ~__m;
344    }
345}
346
347template <class _Cp>
348void
349__fill_n_true(__bit_iterator<_Cp, false> __first, typename _Cp::size_type __n)
350{
351    typedef __bit_iterator<_Cp, false> _It;
352    typedef typename _It::__storage_type __storage_type;
353    const int __bits_per_word = _It::__bits_per_word;
354    // do first partial word
355    if (__first.__ctz_ != 0)
356    {
357        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
358        __storage_type __dn = _VSTD::min(__clz_f, __n);
359        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
360        *__first.__seg_ |= __m;
361        __n -= __dn;
362        ++__first.__seg_;
363    }
364    // do middle whole words
365    __storage_type __nw = __n / __bits_per_word;
366    _VSTD::memset(_VSTD::__to_raw_pointer(__first.__seg_), -1, __nw * sizeof(__storage_type));
367    __n -= __nw * __bits_per_word;
368    // do last partial word
369    if (__n > 0)
370    {
371        __first.__seg_ += __nw;
372        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
373        *__first.__seg_ |= __m;
374    }
375}
376
377template <class _Cp>
378inline _LIBCPP_INLINE_VISIBILITY
379void
380fill_n(__bit_iterator<_Cp, false> __first, typename _Cp::size_type __n, bool __value_)
381{
382    if (__n > 0)
383    {
384        if (__value_)
385            __fill_n_true(__first, __n);
386        else
387            __fill_n_false(__first, __n);
388    }
389}
390
391// fill
392
393template <class _Cp>
394inline _LIBCPP_INLINE_VISIBILITY
395void
396fill(__bit_iterator<_Cp, false> __first, __bit_iterator<_Cp, false> __last, bool __value_)
397{
398    _VSTD::fill_n(__first, static_cast<typename _Cp::size_type>(__last - __first), __value_);
399}
400
401// copy
402
403template <class _Cp, bool _IsConst>
404__bit_iterator<_Cp, false>
405__copy_aligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
406                                                     __bit_iterator<_Cp, false> __result)
407{
408    typedef __bit_iterator<_Cp, _IsConst> _In;
409    typedef  typename _In::difference_type difference_type;
410    typedef typename _In::__storage_type __storage_type;
411    const int __bits_per_word = _In::__bits_per_word;
412    difference_type __n = __last - __first;
413    if (__n > 0)
414    {
415        // do first word
416        if (__first.__ctz_ != 0)
417        {
418            unsigned __clz = __bits_per_word - __first.__ctz_;
419            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz), __n);
420            __n -= __dn;
421            __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz - __dn));
422            __storage_type __b = *__first.__seg_ & __m;
423            *__result.__seg_ &= ~__m;
424            *__result.__seg_ |= __b;
425            __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
426            __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_)  % __bits_per_word);
427            ++__first.__seg_;
428            // __first.__ctz_ = 0;
429        }
430        // __first.__ctz_ == 0;
431        // do middle words
432        __storage_type __nw = __n / __bits_per_word;
433        _VSTD::memmove(_VSTD::__to_raw_pointer(__result.__seg_),
434                       _VSTD::__to_raw_pointer(__first.__seg_),
435                       __nw * sizeof(__storage_type));
436        __n -= __nw * __bits_per_word;
437        __result.__seg_ += __nw;
438        // do last word
439        if (__n > 0)
440        {
441            __first.__seg_ += __nw;
442            __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
443            __storage_type __b = *__first.__seg_ & __m;
444            *__result.__seg_ &= ~__m;
445            *__result.__seg_ |= __b;
446            __result.__ctz_ = static_cast<unsigned>(__n);
447        }
448    }
449    return __result;
450}
451
452template <class _Cp, bool _IsConst>
453__bit_iterator<_Cp, false>
454__copy_unaligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
455                                                       __bit_iterator<_Cp, false> __result)
456{
457    typedef __bit_iterator<_Cp, _IsConst> _In;
458    typedef  typename _In::difference_type difference_type;
459    typedef typename _In::__storage_type __storage_type;
460    static const int __bits_per_word = _In::__bits_per_word;
461    difference_type __n = __last - __first;
462    if (__n > 0)
463    {
464        // do first word
465        if (__first.__ctz_ != 0)
466        {
467            unsigned __clz_f = __bits_per_word - __first.__ctz_;
468            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz_f), __n);
469            __n -= __dn;
470            __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
471            __storage_type __b = *__first.__seg_ & __m;
472            unsigned __clz_r = __bits_per_word - __result.__ctz_;
473            __storage_type __ddn = _VSTD::min<__storage_type>(__dn, __clz_r);
474            __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __ddn));
475            *__result.__seg_ &= ~__m;
476            if (__result.__ctz_ > __first.__ctz_)
477                *__result.__seg_ |= __b << (__result.__ctz_ - __first.__ctz_);
478            else
479                *__result.__seg_ |= __b >> (__first.__ctz_ - __result.__ctz_);
480            __result.__seg_ += (__ddn + __result.__ctz_) / __bits_per_word;
481            __result.__ctz_ = static_cast<unsigned>((__ddn + __result.__ctz_)  % __bits_per_word);
482            __dn -= __ddn;
483            if (__dn > 0)
484            {
485                __m = ~__storage_type(0) >> (__bits_per_word - __dn);
486                *__result.__seg_ &= ~__m;
487                *__result.__seg_ |= __b >> (__first.__ctz_ + __ddn);
488                __result.__ctz_ = static_cast<unsigned>(__dn);
489            }
490            ++__first.__seg_;
491            // __first.__ctz_ = 0;
492        }
493        // __first.__ctz_ == 0;
494        // do middle words
495        unsigned __clz_r = __bits_per_word - __result.__ctz_;
496        __storage_type __m = ~__storage_type(0) << __result.__ctz_;
497        for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first.__seg_)
498        {
499            __storage_type __b = *__first.__seg_;
500            *__result.__seg_ &= ~__m;
501            *__result.__seg_ |= __b << __result.__ctz_;
502            ++__result.__seg_;
503            *__result.__seg_ &= __m;
504            *__result.__seg_ |= __b >> __clz_r;
505        }
506        // do last word
507        if (__n > 0)
508        {
509            __m = ~__storage_type(0) >> (__bits_per_word - __n);
510            __storage_type __b = *__first.__seg_ & __m;
511            __storage_type __dn = _VSTD::min(__n, static_cast<difference_type>(__clz_r));
512            __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __dn));
513            *__result.__seg_ &= ~__m;
514            *__result.__seg_ |= __b << __result.__ctz_;
515            __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
516            __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_)  % __bits_per_word);
517            __n -= __dn;
518            if (__n > 0)
519            {
520                __m = ~__storage_type(0) >> (__bits_per_word - __n);
521                *__result.__seg_ &= ~__m;
522                *__result.__seg_ |= __b >> __dn;
523                __result.__ctz_ = static_cast<unsigned>(__n);
524            }
525        }
526    }
527    return __result;
528}
529
530template <class _Cp, bool _IsConst>
531inline _LIBCPP_INLINE_VISIBILITY
532__bit_iterator<_Cp, false>
533copy(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, __bit_iterator<_Cp, false> __result)
534{
535    if (__first.__ctz_ == __result.__ctz_)
536        return __copy_aligned(__first, __last, __result);
537    return __copy_unaligned(__first, __last, __result);
538}
539
540// copy_backward
541
542template <class _Cp, bool _IsConst>
543__bit_iterator<_Cp, false>
544__copy_backward_aligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
545                                                     __bit_iterator<_Cp, false> __result)
546{
547    typedef __bit_iterator<_Cp, _IsConst> _In;
548    typedef  typename _In::difference_type difference_type;
549    typedef typename _In::__storage_type __storage_type;
550    const int __bits_per_word = _In::__bits_per_word;
551    difference_type __n = __last - __first;
552    if (__n > 0)
553    {
554        // do first word
555        if (__last.__ctz_ != 0)
556        {
557            difference_type __dn = _VSTD::min(static_cast<difference_type>(__last.__ctz_), __n);
558            __n -= __dn;
559            unsigned __clz = __bits_per_word - __last.__ctz_;
560            __storage_type __m = (~__storage_type(0) << (__last.__ctz_ - __dn)) & (~__storage_type(0) >> __clz);
561            __storage_type __b = *__last.__seg_ & __m;
562            *__result.__seg_ &= ~__m;
563            *__result.__seg_ |= __b;
564            __result.__ctz_ = static_cast<unsigned>(((-__dn & (__bits_per_word - 1)) +
565                                                       __result.__ctz_)  % __bits_per_word);
566            // __last.__ctz_ = 0
567         }
568        // __last.__ctz_ == 0 || __n == 0
569        // __result.__ctz_ == 0 || __n == 0
570        // do middle words
571        __storage_type __nw = __n / __bits_per_word;
572        __result.__seg_ -= __nw;
573        __last.__seg_ -= __nw;
574        _VSTD::memmove(_VSTD::__to_raw_pointer(__result.__seg_),
575                       _VSTD::__to_raw_pointer(__last.__seg_),
576                       __nw * sizeof(__storage_type));
577        __n -= __nw * __bits_per_word;
578        // do last word
579        if (__n > 0)
580        {
581            __storage_type __m = ~__storage_type(0) << (__bits_per_word - __n);
582            __storage_type __b = *--__last.__seg_ & __m;
583            *--__result.__seg_ &= ~__m;
584            *__result.__seg_ |= __b;
585            __result.__ctz_ = static_cast<unsigned>(-__n & (__bits_per_word - 1));
586        }
587    }
588    return __result;
589}
590
591template <class _Cp, bool _IsConst>
592__bit_iterator<_Cp, false>
593__copy_backward_unaligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
594                                                       __bit_iterator<_Cp, false> __result)
595{
596    typedef __bit_iterator<_Cp, _IsConst> _In;
597    typedef  typename _In::difference_type difference_type;
598    typedef typename _In::__storage_type __storage_type;
599    const int __bits_per_word = _In::__bits_per_word;
600    difference_type __n = __last - __first;
601    if (__n > 0)
602    {
603        // do first word
604        if (__last.__ctz_ != 0)
605        {
606            difference_type __dn = _VSTD::min(static_cast<difference_type>(__last.__ctz_), __n);
607            __n -= __dn;
608            unsigned __clz_l = __bits_per_word - __last.__ctz_;
609            __storage_type __m = (~__storage_type(0) << (__last.__ctz_ - __dn)) & (~__storage_type(0) >> __clz_l);
610            __storage_type __b = *__last.__seg_ & __m;
611            unsigned __clz_r = __bits_per_word - __result.__ctz_;
612            __storage_type __ddn = _VSTD::min(__dn, static_cast<difference_type>(__result.__ctz_));
613            if (__ddn > 0)
614            {
615                __m = (~__storage_type(0) << (__result.__ctz_ - __ddn)) & (~__storage_type(0) >> __clz_r);
616                *__result.__seg_ &= ~__m;
617                if (__result.__ctz_ > __last.__ctz_)
618                    *__result.__seg_ |= __b << (__result.__ctz_ - __last.__ctz_);
619                else
620                    *__result.__seg_ |= __b >> (__last.__ctz_ - __result.__ctz_);
621                __result.__ctz_ = static_cast<unsigned>(((-__ddn & (__bits_per_word - 1)) +
622                                                         __result.__ctz_)  % __bits_per_word);
623                __dn -= __ddn;
624            }
625            if (__dn > 0)
626            {
627                // __result.__ctz_ == 0
628                --__result.__seg_;
629                __result.__ctz_ = static_cast<unsigned>(-__dn & (__bits_per_word - 1));
630                __m = ~__storage_type(0) << __result.__ctz_;
631                *__result.__seg_ &= ~__m;
632                __last.__ctz_ -= __dn + __ddn;
633                *__result.__seg_ |= __b << (__result.__ctz_ - __last.__ctz_);
634            }
635            // __last.__ctz_ = 0
636         }
637        // __last.__ctz_ == 0 || __n == 0
638        // __result.__ctz_ != 0 || __n == 0
639        // do middle words
640        unsigned __clz_r = __bits_per_word - __result.__ctz_;
641        __storage_type __m = ~__storage_type(0) >> __clz_r;
642        for (; __n >= __bits_per_word; __n -= __bits_per_word)
643        {
644            __storage_type __b = *--__last.__seg_;
645            *__result.__seg_ &= ~__m;
646            *__result.__seg_ |= __b >> __clz_r;
647            *--__result.__seg_ &= __m;
648            *__result.__seg_ |= __b << __result.__ctz_;
649        }
650        // do last word
651        if (__n > 0)
652        {
653            __m = ~__storage_type(0) << (__bits_per_word - __n);
654            __storage_type __b = *--__last.__seg_ & __m;
655            __clz_r = __bits_per_word - __result.__ctz_;
656            __storage_type __dn = _VSTD::min(__n, static_cast<difference_type>(__result.__ctz_));
657            __m = (~__storage_type(0) << (__result.__ctz_ - __dn)) & (~__storage_type(0) >> __clz_r);
658            *__result.__seg_ &= ~__m;
659            *__result.__seg_ |= __b >> (__bits_per_word - __result.__ctz_);
660            __result.__ctz_ = static_cast<unsigned>(((-__dn & (__bits_per_word - 1)) +
661                                                     __result.__ctz_)  % __bits_per_word);
662            __n -= __dn;
663            if (__n > 0)
664            {
665                // __result.__ctz_ == 0
666                --__result.__seg_;
667                __result.__ctz_ = static_cast<unsigned>(-__n & (__bits_per_word - 1));
668                __m = ~__storage_type(0) << __result.__ctz_;
669                *__result.__seg_ &= ~__m;
670                *__result.__seg_ |= __b << (__result.__ctz_ - (__bits_per_word - __n - __dn));
671            }
672        }
673    }
674    return __result;
675}
676
677template <class _Cp, bool _IsConst>
678inline _LIBCPP_INLINE_VISIBILITY
679__bit_iterator<_Cp, false>
680copy_backward(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, __bit_iterator<_Cp, false> __result)
681{
682    if (__last.__ctz_ == __result.__ctz_)
683        return __copy_backward_aligned(__first, __last, __result);
684    return __copy_backward_unaligned(__first, __last, __result);
685}
686
687// move
688
689template <class _Cp, bool _IsConst>
690inline _LIBCPP_INLINE_VISIBILITY
691__bit_iterator<_Cp, false>
692move(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, __bit_iterator<_Cp, false> __result)
693{
694    return _VSTD::copy(__first, __last, __result);
695}
696
697// move_backward
698
699template <class _Cp, bool _IsConst>
700inline _LIBCPP_INLINE_VISIBILITY
701__bit_iterator<_Cp, false>
702move_backward(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, __bit_iterator<_Cp, false> __result)
703{
704    return _VSTD::copy_backward(__first, __last, __result);
705}
706
707// swap_ranges
708
709template <class __C1, class __C2>
710__bit_iterator<__C2, false>
711__swap_ranges_aligned(__bit_iterator<__C1, false> __first, __bit_iterator<__C1, false> __last,
712                      __bit_iterator<__C2, false> __result)
713{
714    typedef __bit_iterator<__C1, false> _I1;
715    typedef  typename _I1::difference_type difference_type;
716    typedef typename _I1::__storage_type __storage_type;
717    const int __bits_per_word = _I1::__bits_per_word;
718    difference_type __n = __last - __first;
719    if (__n > 0)
720    {
721        // do first word
722        if (__first.__ctz_ != 0)
723        {
724            unsigned __clz = __bits_per_word - __first.__ctz_;
725            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz), __n);
726            __n -= __dn;
727            __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz - __dn));
728            __storage_type __b1 = *__first.__seg_ & __m;
729            *__first.__seg_ &= ~__m;
730            __storage_type __b2 = *__result.__seg_ & __m;
731            *__result.__seg_ &= ~__m;
732            *__result.__seg_ |= __b1;
733            *__first.__seg_  |= __b2;
734            __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
735            __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_)  % __bits_per_word);
736            ++__first.__seg_;
737            // __first.__ctz_ = 0;
738        }
739        // __first.__ctz_ == 0;
740        // do middle words
741        for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first.__seg_, ++__result.__seg_)
742            swap(*__first.__seg_, *__result.__seg_);
743        // do last word
744        if (__n > 0)
745        {
746            __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
747            __storage_type __b1 = *__first.__seg_ & __m;
748            *__first.__seg_ &= ~__m;
749            __storage_type __b2 = *__result.__seg_ & __m;
750            *__result.__seg_ &= ~__m;
751            *__result.__seg_ |= __b1;
752            *__first.__seg_  |= __b2;
753            __result.__ctz_ = static_cast<unsigned>(__n);
754        }
755    }
756    return __result;
757}
758
759template <class __C1, class __C2>
760__bit_iterator<__C2, false>
761__swap_ranges_unaligned(__bit_iterator<__C1, false> __first, __bit_iterator<__C1, false> __last,
762                        __bit_iterator<__C2, false> __result)
763{
764    typedef __bit_iterator<__C1, false> _I1;
765    typedef  typename _I1::difference_type difference_type;
766    typedef typename _I1::__storage_type __storage_type;
767    const int __bits_per_word = _I1::__bits_per_word;
768    difference_type __n = __last - __first;
769    if (__n > 0)
770    {
771        // do first word
772        if (__first.__ctz_ != 0)
773        {
774            unsigned __clz_f = __bits_per_word - __first.__ctz_;
775            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz_f), __n);
776            __n -= __dn;
777            __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
778            __storage_type __b1 = *__first.__seg_ & __m;
779            *__first.__seg_ &= ~__m;
780            unsigned __clz_r = __bits_per_word - __result.__ctz_;
781            __storage_type __ddn = _VSTD::min<__storage_type>(__dn, __clz_r);
782            __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __ddn));
783            __storage_type __b2 = *__result.__seg_ & __m;
784            *__result.__seg_ &= ~__m;
785            if (__result.__ctz_ > __first.__ctz_)
786            {
787                unsigned __s = __result.__ctz_ - __first.__ctz_;
788                *__result.__seg_ |= __b1 << __s;
789                *__first.__seg_  |= __b2 >> __s;
790            }
791            else
792            {
793                unsigned __s = __first.__ctz_ - __result.__ctz_;
794                *__result.__seg_ |= __b1 >> __s;
795                *__first.__seg_  |= __b2 << __s;
796            }
797            __result.__seg_ += (__ddn + __result.__ctz_) / __bits_per_word;
798            __result.__ctz_ = static_cast<unsigned>((__ddn + __result.__ctz_)  % __bits_per_word);
799            __dn -= __ddn;
800            if (__dn > 0)
801            {
802                __m = ~__storage_type(0) >> (__bits_per_word - __dn);
803                __b2 = *__result.__seg_ & __m;
804                *__result.__seg_ &= ~__m;
805                unsigned __s = __first.__ctz_ + __ddn;
806                *__result.__seg_ |= __b1 >> __s;
807                *__first.__seg_  |= __b2 << __s;
808                __result.__ctz_ = static_cast<unsigned>(__dn);
809            }
810            ++__first.__seg_;
811            // __first.__ctz_ = 0;
812        }
813        // __first.__ctz_ == 0;
814        // do middle words
815        __storage_type __m = ~__storage_type(0) << __result.__ctz_;
816        unsigned __clz_r = __bits_per_word - __result.__ctz_;
817        for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first.__seg_)
818        {
819            __storage_type __b1 = *__first.__seg_;
820            __storage_type __b2 = *__result.__seg_ & __m;
821            *__result.__seg_ &= ~__m;
822            *__result.__seg_ |= __b1 << __result.__ctz_;
823            *__first.__seg_  = __b2 >> __result.__ctz_;
824            ++__result.__seg_;
825            __b2 = *__result.__seg_ & ~__m;
826            *__result.__seg_ &= __m;
827            *__result.__seg_ |= __b1 >> __clz_r;
828            *__first.__seg_  |= __b2 << __clz_r;
829        }
830        // do last word
831        if (__n > 0)
832        {
833            __m = ~__storage_type(0) >> (__bits_per_word - __n);
834            __storage_type __b1 = *__first.__seg_ & __m;
835            *__first.__seg_ &= ~__m;
836            __storage_type __dn = _VSTD::min<__storage_type>(__n, __clz_r);
837            __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __dn));
838            __storage_type __b2 = *__result.__seg_ & __m;
839            *__result.__seg_ &= ~__m;
840            *__result.__seg_ |= __b1 << __result.__ctz_;
841            *__first.__seg_  |= __b2 >> __result.__ctz_;
842            __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
843            __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_)  % __bits_per_word);
844            __n -= __dn;
845            if (__n > 0)
846            {
847                __m = ~__storage_type(0) >> (__bits_per_word - __n);
848                __b2 = *__result.__seg_ & __m;
849                *__result.__seg_ &= ~__m;
850                *__result.__seg_ |= __b1 >> __dn;
851                *__first.__seg_  |= __b2 << __dn;
852                __result.__ctz_ = static_cast<unsigned>(__n);
853            }
854        }
855    }
856    return __result;
857}
858
859template <class __C1, class __C2>
860inline _LIBCPP_INLINE_VISIBILITY
861__bit_iterator<__C2, false>
862swap_ranges(__bit_iterator<__C1, false> __first1, __bit_iterator<__C1, false> __last1,
863            __bit_iterator<__C2, false> __first2)
864{
865    if (__first1.__ctz_ == __first2.__ctz_)
866        return __swap_ranges_aligned(__first1, __last1, __first2);
867    return __swap_ranges_unaligned(__first1, __last1, __first2);
868}
869
870// rotate
871
872template <class _Cp>
873struct __bit_array
874{
875    typedef typename _Cp::difference_type difference_type;
876    typedef typename _Cp::__storage_type  __storage_type;
877    typedef typename _Cp::__storage_pointer __storage_pointer;
878    typedef typename _Cp::iterator        iterator;
879    static const unsigned __bits_per_word = _Cp::__bits_per_word;
880    static const unsigned _Np = 4;
881
882    difference_type __size_;
883    __storage_type __word_[_Np];
884
885    _LIBCPP_INLINE_VISIBILITY static difference_type capacity()
886        {return static_cast<difference_type>(_Np * __bits_per_word);}
887    _LIBCPP_INLINE_VISIBILITY explicit __bit_array(difference_type __s) : __size_(__s) {}
888    _LIBCPP_INLINE_VISIBILITY iterator begin()
889    {
890        return iterator(pointer_traits<__storage_pointer>::pointer_to(__word_[0]), 0);
891    }
892    _LIBCPP_INLINE_VISIBILITY iterator end()
893    {
894        return iterator(pointer_traits<__storage_pointer>::pointer_to(__word_[0]) + __size_ / __bits_per_word,
895                                                  static_cast<unsigned>(__size_ % __bits_per_word));
896    }
897};
898
899template <class _Cp>
900__bit_iterator<_Cp, false>
901rotate(__bit_iterator<_Cp, false> __first, __bit_iterator<_Cp, false> __middle, __bit_iterator<_Cp, false> __last)
902{
903    typedef __bit_iterator<_Cp, false> _I1;
904    typedef  typename _I1::difference_type difference_type;
905    difference_type __d1 = __middle - __first;
906    difference_type __d2 = __last - __middle;
907    _I1 __r = __first + __d2;
908    while (__d1 != 0 && __d2 != 0)
909    {
910        if (__d1 <= __d2)
911        {
912            if (__d1 <= __bit_array<_Cp>::capacity())
913            {
914                __bit_array<_Cp> __b(__d1);
915                _VSTD::copy(__first, __middle, __b.begin());
916                _VSTD::copy(__b.begin(), __b.end(), _VSTD::copy(__middle, __last, __first));
917                break;
918            }
919            else
920            {
921                __bit_iterator<_Cp, false> __mp = _VSTD::swap_ranges(__first, __middle, __middle);
922                __first = __middle;
923                __middle = __mp;
924                __d2 -= __d1;
925            }
926        }
927        else
928        {
929            if (__d2 <= __bit_array<_Cp>::capacity())
930            {
931                __bit_array<_Cp> __b(__d2);
932                _VSTD::copy(__middle, __last, __b.begin());
933                _VSTD::copy_backward(__b.begin(), __b.end(), _VSTD::copy_backward(__first, __middle, __last));
934                break;
935            }
936            else
937            {
938                __bit_iterator<_Cp, false> __mp = __first + __d2;
939                _VSTD::swap_ranges(__first, __mp, __middle);
940                __first = __mp;
941                __d1 -= __d2;
942            }
943        }
944    }
945    return __r;
946}
947
948// equal
949
950template <class _Cp, bool _IC1, bool _IC2>
951bool
952__equal_unaligned(__bit_iterator<_Cp, _IC1> __first1, __bit_iterator<_Cp, _IC1> __last1,
953                  __bit_iterator<_Cp, _IC2> __first2)
954{
955    typedef __bit_iterator<_Cp, _IC1> _It;
956    typedef  typename _It::difference_type difference_type;
957    typedef typename _It::__storage_type __storage_type;
958    static const int __bits_per_word = _It::__bits_per_word;
959    difference_type __n = __last1 - __first1;
960    if (__n > 0)
961    {
962        // do first word
963        if (__first1.__ctz_ != 0)
964        {
965            unsigned __clz_f = __bits_per_word - __first1.__ctz_;
966            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz_f), __n);
967            __n -= __dn;
968            __storage_type __m = (~__storage_type(0) << __first1.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
969            __storage_type __b = *__first1.__seg_ & __m;
970            unsigned __clz_r = __bits_per_word - __first2.__ctz_;
971            __storage_type __ddn = _VSTD::min<__storage_type>(__dn, __clz_r);
972            __m = (~__storage_type(0) << __first2.__ctz_) & (~__storage_type(0) >> (__clz_r - __ddn));
973            if (__first2.__ctz_ > __first1.__ctz_)
974            {
975                if ((*__first2.__seg_ & __m) != (__b << (__first2.__ctz_ - __first1.__ctz_)))
976                    return false;
977            }
978            else
979            {
980                if ((*__first2.__seg_ & __m) != (__b >> (__first1.__ctz_ - __first2.__ctz_)))
981                    return false;
982            }
983            __first2.__seg_ += (__ddn + __first2.__ctz_) / __bits_per_word;
984            __first2.__ctz_ = static_cast<unsigned>((__ddn + __first2.__ctz_)  % __bits_per_word);
985            __dn -= __ddn;
986            if (__dn > 0)
987            {
988                __m = ~__storage_type(0) >> (__bits_per_word - __dn);
989                if ((*__first2.__seg_ & __m) != (__b >> (__first1.__ctz_ + __ddn)))
990                    return false;
991                __first2.__ctz_ = static_cast<unsigned>(__dn);
992            }
993            ++__first1.__seg_;
994            // __first1.__ctz_ = 0;
995        }
996        // __first1.__ctz_ == 0;
997        // do middle words
998        unsigned __clz_r = __bits_per_word - __first2.__ctz_;
999        __storage_type __m = ~__storage_type(0) << __first2.__ctz_;
1000        for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first1.__seg_)
1001        {
1002            __storage_type __b = *__first1.__seg_;
1003            if ((*__first2.__seg_ & __m) != (__b << __first2.__ctz_))
1004                return false;
1005            ++__first2.__seg_;
1006            if ((*__first2.__seg_ & ~__m) != (__b >> __clz_r))
1007                return false;
1008        }
1009        // do last word
1010        if (__n > 0)
1011        {
1012            __m = ~__storage_type(0) >> (__bits_per_word - __n);
1013            __storage_type __b = *__first1.__seg_ & __m;
1014            __storage_type __dn = _VSTD::min(__n, static_cast<difference_type>(__clz_r));
1015            __m = (~__storage_type(0) << __first2.__ctz_) & (~__storage_type(0) >> (__clz_r - __dn));
1016            if ((*__first2.__seg_ & __m) != (__b << __first2.__ctz_))
1017                return false;
1018            __first2.__seg_ += (__dn + __first2.__ctz_) / __bits_per_word;
1019            __first2.__ctz_ = static_cast<unsigned>((__dn + __first2.__ctz_)  % __bits_per_word);
1020            __n -= __dn;
1021            if (__n > 0)
1022            {
1023                __m = ~__storage_type(0) >> (__bits_per_word - __n);
1024                if ((*__first2.__seg_ & __m) != (__b >> __dn))
1025                    return false;
1026            }
1027        }
1028    }
1029    return true;
1030}
1031
1032template <class _Cp, bool _IC1, bool _IC2>
1033bool
1034__equal_aligned(__bit_iterator<_Cp, _IC1> __first1, __bit_iterator<_Cp, _IC1> __last1,
1035                __bit_iterator<_Cp, _IC2> __first2)
1036{
1037    typedef __bit_iterator<_Cp, _IC1> _It;
1038    typedef  typename _It::difference_type difference_type;
1039    typedef typename _It::__storage_type __storage_type;
1040    static const int __bits_per_word = _It::__bits_per_word;
1041    difference_type __n = __last1 - __first1;
1042    if (__n > 0)
1043    {
1044        // do first word
1045        if (__first1.__ctz_ != 0)
1046        {
1047            unsigned __clz = __bits_per_word - __first1.__ctz_;
1048            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz), __n);
1049            __n -= __dn;
1050            __storage_type __m = (~__storage_type(0) << __first1.__ctz_) & (~__storage_type(0) >> (__clz - __dn));
1051            if ((*__first2.__seg_ & __m) != (*__first1.__seg_ & __m))
1052                return false;
1053            ++__first2.__seg_;
1054            ++__first1.__seg_;
1055            // __first1.__ctz_ = 0;
1056            // __first2.__ctz_ = 0;
1057        }
1058        // __first1.__ctz_ == 0;
1059        // __first2.__ctz_ == 0;
1060        // do middle words
1061        for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first1.__seg_, ++__first2.__seg_)
1062            if (*__first2.__seg_ != *__first1.__seg_)
1063                return false;
1064        // do last word
1065        if (__n > 0)
1066        {
1067            __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
1068            if ((*__first2.__seg_ & __m) != (*__first1.__seg_ & __m))
1069                return false;
1070        }
1071    }
1072    return true;
1073}
1074
1075template <class _Cp, bool _IC1, bool _IC2>
1076inline _LIBCPP_INLINE_VISIBILITY
1077bool
1078equal(__bit_iterator<_Cp, _IC1> __first1, __bit_iterator<_Cp, _IC1> __last1, __bit_iterator<_Cp, _IC2> __first2)
1079{
1080    if (__first1.__ctz_ == __first2.__ctz_)
1081        return __equal_aligned(__first1, __last1, __first2);
1082    return __equal_unaligned(__first1, __last1, __first2);
1083}
1084
1085template <class _Cp, bool _IsConst,
1086          typename _Cp::__storage_type>
1087class __bit_iterator
1088{
1089public:
1090    typedef typename _Cp::difference_type                                                          difference_type;
1091    typedef bool                                                                                  value_type;
1092    typedef __bit_iterator                                                                        pointer;
1093    typedef typename conditional<_IsConst, __bit_const_reference<_Cp>, __bit_reference<_Cp> >::type reference;
1094    typedef random_access_iterator_tag                                                            iterator_category;
1095
1096private:
1097    typedef typename _Cp::__storage_type                                           __storage_type;
1098    typedef typename conditional<_IsConst, typename _Cp::__const_storage_pointer,
1099                                           typename _Cp::__storage_pointer>::type  __storage_pointer;
1100    static const unsigned __bits_per_word = _Cp::__bits_per_word;
1101
1102    __storage_pointer __seg_;
1103    unsigned          __ctz_;
1104
1105public:
1106    _LIBCPP_INLINE_VISIBILITY __bit_iterator() _NOEXCEPT
1107#if _LIBCPP_STD_VER > 11
1108    : __seg_(nullptr), __ctz_(0)
1109#endif
1110    {}
1111
1112    _LIBCPP_INLINE_VISIBILITY
1113    __bit_iterator(const __bit_iterator<_Cp, false>& __it) _NOEXCEPT
1114        : __seg_(__it.__seg_), __ctz_(__it.__ctz_) {}
1115
1116    _LIBCPP_INLINE_VISIBILITY reference operator*() const _NOEXCEPT
1117        {return reference(__seg_, __storage_type(1) << __ctz_);}
1118
1119    _LIBCPP_INLINE_VISIBILITY __bit_iterator& operator++()
1120    {
1121        if (__ctz_ != __bits_per_word-1)
1122            ++__ctz_;
1123        else
1124        {
1125            __ctz_ = 0;
1126            ++__seg_;
1127        }
1128        return *this;
1129    }
1130
1131    _LIBCPP_INLINE_VISIBILITY __bit_iterator operator++(int)
1132    {
1133        __bit_iterator __tmp = *this;
1134        ++(*this);
1135        return __tmp;
1136    }
1137
1138    _LIBCPP_INLINE_VISIBILITY __bit_iterator& operator--()
1139    {
1140        if (__ctz_ != 0)
1141            --__ctz_;
1142        else
1143        {
1144            __ctz_ = __bits_per_word - 1;
1145            --__seg_;
1146        }
1147        return *this;
1148    }
1149
1150    _LIBCPP_INLINE_VISIBILITY __bit_iterator operator--(int)
1151    {
1152        __bit_iterator __tmp = *this;
1153        --(*this);
1154        return __tmp;
1155    }
1156
1157    _LIBCPP_INLINE_VISIBILITY __bit_iterator& operator+=(difference_type __n)
1158    {
1159        if (__n >= 0)
1160            __seg_ += (__n + __ctz_) / __bits_per_word;
1161        else
1162            __seg_ += static_cast<difference_type>(__n - __bits_per_word + __ctz_ + 1)
1163                    / static_cast<difference_type>(__bits_per_word);
1164        __n &= (__bits_per_word - 1);
1165        __ctz_ = static_cast<unsigned>((__n + __ctz_)  % __bits_per_word);
1166        return *this;
1167    }
1168
1169    _LIBCPP_INLINE_VISIBILITY __bit_iterator& operator-=(difference_type __n)
1170    {
1171        return *this += -__n;
1172    }
1173
1174    _LIBCPP_INLINE_VISIBILITY __bit_iterator operator+(difference_type __n) const
1175    {
1176        __bit_iterator __t(*this);
1177        __t += __n;
1178        return __t;
1179    }
1180
1181    _LIBCPP_INLINE_VISIBILITY __bit_iterator operator-(difference_type __n) const
1182    {
1183        __bit_iterator __t(*this);
1184        __t -= __n;
1185        return __t;
1186    }
1187
1188    _LIBCPP_INLINE_VISIBILITY
1189    friend __bit_iterator operator+(difference_type __n, const __bit_iterator& __it) {return __it + __n;}
1190
1191    _LIBCPP_INLINE_VISIBILITY
1192    friend difference_type operator-(const __bit_iterator& __x, const __bit_iterator& __y)
1193        {return (__x.__seg_ - __y.__seg_) * __bits_per_word + __x.__ctz_ - __y.__ctz_;}
1194
1195    _LIBCPP_INLINE_VISIBILITY reference operator[](difference_type __n) const {return *(*this + __n);}
1196
1197    _LIBCPP_INLINE_VISIBILITY friend bool operator==(const __bit_iterator& __x, const __bit_iterator& __y)
1198        {return __x.__seg_ == __y.__seg_ && __x.__ctz_ == __y.__ctz_;}
1199
1200    _LIBCPP_INLINE_VISIBILITY friend bool operator!=(const __bit_iterator& __x, const __bit_iterator& __y)
1201        {return !(__x == __y);}
1202
1203    _LIBCPP_INLINE_VISIBILITY friend bool operator<(const __bit_iterator& __x, const __bit_iterator& __y)
1204        {return __x.__seg_ < __y.__seg_ || (__x.__seg_ == __y.__seg_ && __x.__ctz_ < __y.__ctz_);}
1205
1206    _LIBCPP_INLINE_VISIBILITY friend bool operator>(const __bit_iterator& __x, const __bit_iterator& __y)
1207        {return __y < __x;}
1208
1209    _LIBCPP_INLINE_VISIBILITY friend bool operator<=(const __bit_iterator& __x, const __bit_iterator& __y)
1210        {return !(__y < __x);}
1211
1212    _LIBCPP_INLINE_VISIBILITY friend bool operator>=(const __bit_iterator& __x, const __bit_iterator& __y)
1213        {return !(__x < __y);}
1214
1215private:
1216    _LIBCPP_INLINE_VISIBILITY
1217    __bit_iterator(__storage_pointer __s, unsigned __ctz) _NOEXCEPT
1218        : __seg_(__s), __ctz_(__ctz) {}
1219
1220    friend typename _Cp::__self;
1221
1222    friend class __bit_reference<_Cp>;
1223    friend class __bit_const_reference<_Cp>;
1224    friend class __bit_iterator<_Cp, true>;
1225    template <class _Dp> friend struct __bit_array;
1226    template <class _Dp> friend void __fill_n_false(__bit_iterator<_Dp, false> __first, typename _Dp::size_type __n);
1227    template <class _Dp> friend void __fill_n_true(__bit_iterator<_Dp, false> __first, typename _Dp::size_type __n);
1228    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> __copy_aligned(__bit_iterator<_Dp, _IC> __first,
1229                                                                                  __bit_iterator<_Dp, _IC> __last,
1230                                                                                  __bit_iterator<_Dp, false> __result);
1231    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> __copy_unaligned(__bit_iterator<_Dp, _IC> __first,
1232                                                                                    __bit_iterator<_Dp, _IC> __last,
1233                                                                                    __bit_iterator<_Dp, false> __result);
1234    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> copy(__bit_iterator<_Dp, _IC> __first,
1235                                                                        __bit_iterator<_Dp, _IC> __last,
1236                                                                        __bit_iterator<_Dp, false> __result);
1237    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> __copy_backward_aligned(__bit_iterator<_Dp, _IC> __first,
1238                                                                                           __bit_iterator<_Dp, _IC> __last,
1239                                                                                           __bit_iterator<_Dp, false> __result);
1240    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> __copy_backward_unaligned(__bit_iterator<_Dp, _IC> __first,
1241                                                                                             __bit_iterator<_Dp, _IC> __last,
1242                                                                                             __bit_iterator<_Dp, false> __result);
1243    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> copy_backward(__bit_iterator<_Dp, _IC> __first,
1244                                                                                 __bit_iterator<_Dp, _IC> __last,
1245                                                                                 __bit_iterator<_Dp, false> __result);
1246    template <class __C1, class __C2>friend __bit_iterator<__C2, false> __swap_ranges_aligned(__bit_iterator<__C1, false>,
1247                                                                                           __bit_iterator<__C1, false>,
1248                                                                                           __bit_iterator<__C2, false>);
1249    template <class __C1, class __C2>friend __bit_iterator<__C2, false> __swap_ranges_unaligned(__bit_iterator<__C1, false>,
1250                                                                                             __bit_iterator<__C1, false>,
1251                                                                                             __bit_iterator<__C2, false>);
1252    template <class __C1, class __C2>friend __bit_iterator<__C2, false> swap_ranges(__bit_iterator<__C1, false>,
1253                                                                                 __bit_iterator<__C1, false>,
1254                                                                                 __bit_iterator<__C2, false>);
1255    template <class _Dp> friend __bit_iterator<_Dp, false> rotate(__bit_iterator<_Dp, false>,
1256                                                                __bit_iterator<_Dp, false>,
1257                                                                __bit_iterator<_Dp, false>);
1258    template <class _Dp, bool _IC1, bool _IC2> friend bool __equal_aligned(__bit_iterator<_Dp, _IC1>,
1259                                                    __bit_iterator<_Dp, _IC1>,
1260                                                    __bit_iterator<_Dp, _IC2>);
1261    template <class _Dp, bool _IC1, bool _IC2> friend bool __equal_unaligned(__bit_iterator<_Dp, _IC1>,
1262                                                      __bit_iterator<_Dp, _IC1>,
1263                                                      __bit_iterator<_Dp, _IC2>);
1264    template <class _Dp, bool _IC1, bool _IC2> friend bool equal(__bit_iterator<_Dp, _IC1>,
1265                                                                __bit_iterator<_Dp, _IC1>,
1266                                                                __bit_iterator<_Dp, _IC2>);
1267    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, _IC> __find_bool_true(__bit_iterator<_Dp, _IC>,
1268                                                                          typename _Dp::size_type);
1269    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, _IC> __find_bool_false(__bit_iterator<_Dp, _IC>,
1270                                                                           typename _Dp::size_type);
1271    template <class _Dp, bool _IC> friend typename __bit_iterator<_Dp, _IC>::difference_type
1272                   __count_bool_true(__bit_iterator<_Dp, _IC>, typename _Dp::size_type);
1273    template <class _Dp, bool _IC> friend typename __bit_iterator<_Dp, _IC>::difference_type
1274                   __count_bool_false(__bit_iterator<_Dp, _IC>, typename _Dp::size_type);
1275};
1276
1277_LIBCPP_END_NAMESPACE_STD
1278
1279_LIBCPP_POP_MACROS
1280
1281#endif  // _LIBCPP___BIT_REFERENCE
1282