xref: /llvm-project-15.0.7/libcxx/include/string (revision 746bb5e4)
1// -*- C++ -*-
2//===--------------------------- string -----------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is distributed under the University of Illinois Open Source
7// License. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_STRING
12#define _LIBCPP_STRING
13
14/*
15    string synopsis
16
17namespace std
18{
19
20template <class stateT>
21class fpos
22{
23private:
24    stateT st;
25public:
26    fpos(streamoff = streamoff());
27
28    operator streamoff() const;
29
30    stateT state() const;
31    void state(stateT);
32
33    fpos& operator+=(streamoff);
34    fpos  operator+ (streamoff) const;
35    fpos& operator-=(streamoff);
36    fpos  operator- (streamoff) const;
37};
38
39template <class stateT> streamoff operator-(const fpos<stateT>& x, const fpos<stateT>& y);
40
41template <class stateT> bool operator==(const fpos<stateT>& x, const fpos<stateT>& y);
42template <class stateT> bool operator!=(const fpos<stateT>& x, const fpos<stateT>& y);
43
44template <class charT>
45struct char_traits
46{
47    typedef charT     char_type;
48    typedef ...       int_type;
49    typedef streamoff off_type;
50    typedef streampos pos_type;
51    typedef mbstate_t state_type;
52
53    static void assign(char_type& c1, const char_type& c2) noexcept;
54    static constexpr bool eq(char_type c1, char_type c2) noexcept;
55    static constexpr bool lt(char_type c1, char_type c2) noexcept;
56
57    static int              compare(const char_type* s1, const char_type* s2, size_t n);
58    static size_t           length(const char_type* s);
59    static const char_type* find(const char_type* s, size_t n, const char_type& a);
60    static char_type*       move(char_type* s1, const char_type* s2, size_t n);
61    static char_type*       copy(char_type* s1, const char_type* s2, size_t n);
62    static char_type*       assign(char_type* s, size_t n, char_type a);
63
64    static constexpr int_type  not_eof(int_type c) noexcept;
65    static constexpr char_type to_char_type(int_type c) noexcept;
66    static constexpr int_type  to_int_type(char_type c) noexcept;
67    static constexpr bool      eq_int_type(int_type c1, int_type c2) noexcept;
68    static constexpr int_type  eof() noexcept;
69};
70
71template <> struct char_traits<char>;
72template <> struct char_traits<wchar_t>;
73
74template<class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
75class basic_string
76{
77public:
78// types:
79    typedef traits traits_type;
80    typedef typename traits_type::char_type value_type;
81    typedef Allocator allocator_type;
82    typedef typename allocator_type::size_type size_type;
83    typedef typename allocator_type::difference_type difference_type;
84    typedef typename allocator_type::reference reference;
85    typedef typename allocator_type::const_reference const_reference;
86    typedef typename allocator_type::pointer pointer;
87    typedef typename allocator_type::const_pointer const_pointer;
88    typedef implementation-defined iterator;
89    typedef implementation-defined const_iterator;
90    typedef std::reverse_iterator<iterator> reverse_iterator;
91    typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
92
93    static const size_type npos = -1;
94
95    basic_string()
96        noexcept(is_nothrow_default_constructible<allocator_type>::value);
97    explicit basic_string(const allocator_type& a);
98    basic_string(const basic_string& str);
99    basic_string(basic_string&& str)
100        noexcept(is_nothrow_move_constructible<allocator_type>::value);
101    basic_string(const basic_string& str, size_type pos, size_type n = npos,
102                 const allocator_type& a = allocator_type());
103    basic_string(const value_type* s, const allocator_type& a = allocator_type());
104    basic_string(const value_type* s, size_type n, const allocator_type& a = allocator_type());
105    basic_string(size_type n, value_type c, const allocator_type& a = allocator_type());
106    template<class InputIterator>
107        basic_string(InputIterator begin, InputIterator end,
108                     const allocator_type& a = allocator_type());
109    basic_string(initializer_list<value_type>, const Allocator& = Allocator());
110    basic_string(const basic_string&, const Allocator&);
111    basic_string(basic_string&&, const Allocator&);
112
113    ~basic_string();
114
115    basic_string& operator=(const basic_string& str);
116    basic_string& operator=(basic_string&& str)
117        noexcept(
118             allocator_type::propagate_on_container_move_assignment::value ||
119             allocator_type::is_always_equal::value ); // C++17
120    basic_string& operator=(const value_type* s);
121    basic_string& operator=(value_type c);
122    basic_string& operator=(initializer_list<value_type>);
123
124    iterator       begin() noexcept;
125    const_iterator begin() const noexcept;
126    iterator       end() noexcept;
127    const_iterator end() const noexcept;
128
129    reverse_iterator       rbegin() noexcept;
130    const_reverse_iterator rbegin() const noexcept;
131    reverse_iterator       rend() noexcept;
132    const_reverse_iterator rend() const noexcept;
133
134    const_iterator         cbegin() const noexcept;
135    const_iterator         cend() const noexcept;
136    const_reverse_iterator crbegin() const noexcept;
137    const_reverse_iterator crend() const noexcept;
138
139    size_type size() const noexcept;
140    size_type length() const noexcept;
141    size_type max_size() const noexcept;
142    size_type capacity() const noexcept;
143
144    void resize(size_type n, value_type c);
145    void resize(size_type n);
146
147    void reserve(size_type res_arg = 0);
148    void shrink_to_fit();
149    void clear() noexcept;
150    bool empty() const noexcept;
151
152    const_reference operator[](size_type pos) const;
153    reference       operator[](size_type pos);
154
155    const_reference at(size_type n) const;
156    reference       at(size_type n);
157
158    basic_string& operator+=(const basic_string& str);
159    basic_string& operator+=(const value_type* s);
160    basic_string& operator+=(value_type c);
161    basic_string& operator+=(initializer_list<value_type>);
162
163    basic_string& append(const basic_string& str);
164    basic_string& append(const basic_string& str, size_type pos, size_type n=npos); //C++14
165    basic_string& append(const value_type* s, size_type n);
166    basic_string& append(const value_type* s);
167    basic_string& append(size_type n, value_type c);
168    template<class InputIterator>
169        basic_string& append(InputIterator first, InputIterator last);
170    basic_string& append(initializer_list<value_type>);
171
172    void push_back(value_type c);
173    void pop_back();
174    reference       front();
175    const_reference front() const;
176    reference       back();
177    const_reference back() const;
178
179    basic_string& assign(const basic_string& str);
180    basic_string& assign(basic_string&& str);
181    basic_string& assign(const basic_string& str, size_type pos, size_type n=npos); // C++14
182    basic_string& assign(const value_type* s, size_type n);
183    basic_string& assign(const value_type* s);
184    basic_string& assign(size_type n, value_type c);
185    template<class InputIterator>
186        basic_string& assign(InputIterator first, InputIterator last);
187    basic_string& assign(initializer_list<value_type>);
188
189    basic_string& insert(size_type pos1, const basic_string& str);
190    basic_string& insert(size_type pos1, const basic_string& str,
191                         size_type pos2, size_type n);
192    basic_string& insert(size_type pos, const value_type* s, size_type n=npos); //C++14
193    basic_string& insert(size_type pos, const value_type* s);
194    basic_string& insert(size_type pos, size_type n, value_type c);
195    iterator      insert(const_iterator p, value_type c);
196    iterator      insert(const_iterator p, size_type n, value_type c);
197    template<class InputIterator>
198        iterator insert(const_iterator p, InputIterator first, InputIterator last);
199    iterator      insert(const_iterator p, initializer_list<value_type>);
200
201    basic_string& erase(size_type pos = 0, size_type n = npos);
202    iterator      erase(const_iterator position);
203    iterator      erase(const_iterator first, const_iterator last);
204
205    basic_string& replace(size_type pos1, size_type n1, const basic_string& str);
206    basic_string& replace(size_type pos1, size_type n1, const basic_string& str,
207                          size_type pos2, size_type n2=npos); // C++14
208    basic_string& replace(size_type pos, size_type n1, const value_type* s, size_type n2);
209    basic_string& replace(size_type pos, size_type n1, const value_type* s);
210    basic_string& replace(size_type pos, size_type n1, size_type n2, value_type c);
211    basic_string& replace(const_iterator i1, const_iterator i2, const basic_string& str);
212    basic_string& replace(const_iterator i1, const_iterator i2, const value_type* s, size_type n);
213    basic_string& replace(const_iterator i1, const_iterator i2, const value_type* s);
214    basic_string& replace(const_iterator i1, const_iterator i2, size_type n, value_type c);
215    template<class InputIterator>
216        basic_string& replace(const_iterator i1, const_iterator i2, InputIterator j1, InputIterator j2);
217    basic_string& replace(const_iterator i1, const_iterator i2, initializer_list<value_type>);
218
219    size_type copy(value_type* s, size_type n, size_type pos = 0) const;
220    basic_string substr(size_type pos = 0, size_type n = npos) const;
221
222    void swap(basic_string& str)
223        noexcept(allocator_traits<allocator_type>::propagate_on_container_swap::value ||
224                 allocator_traits<allocator_type>::is_always_equal::value);  // C++17
225
226    const value_type* c_str() const noexcept;
227    const value_type* data() const noexcept;
228
229    allocator_type get_allocator() const noexcept;
230
231    size_type find(const basic_string& str, size_type pos = 0) const noexcept;
232    size_type find(const value_type* s, size_type pos, size_type n) const noexcept;
233    size_type find(const value_type* s, size_type pos = 0) const noexcept;
234    size_type find(value_type c, size_type pos = 0) const noexcept;
235
236    size_type rfind(const basic_string& str, size_type pos = npos) const noexcept;
237    size_type rfind(const value_type* s, size_type pos, size_type n) const noexcept;
238    size_type rfind(const value_type* s, size_type pos = npos) const noexcept;
239    size_type rfind(value_type c, size_type pos = npos) const noexcept;
240
241    size_type find_first_of(const basic_string& str, size_type pos = 0) const noexcept;
242    size_type find_first_of(const value_type* s, size_type pos, size_type n) const noexcept;
243    size_type find_first_of(const value_type* s, size_type pos = 0) const noexcept;
244    size_type find_first_of(value_type c, size_type pos = 0) const noexcept;
245
246    size_type find_last_of(const basic_string& str, size_type pos = npos) const noexcept;
247    size_type find_last_of(const value_type* s, size_type pos, size_type n) const noexcept;
248    size_type find_last_of(const value_type* s, size_type pos = npos) const noexcept;
249    size_type find_last_of(value_type c, size_type pos = npos) const noexcept;
250
251    size_type find_first_not_of(const basic_string& str, size_type pos = 0) const noexcept;
252    size_type find_first_not_of(const value_type* s, size_type pos, size_type n) const noexcept;
253    size_type find_first_not_of(const value_type* s, size_type pos = 0) const noexcept;
254    size_type find_first_not_of(value_type c, size_type pos = 0) const noexcept;
255
256    size_type find_last_not_of(const basic_string& str, size_type pos = npos) const noexcept;
257    size_type find_last_not_of(const value_type* s, size_type pos, size_type n) const noexcept;
258    size_type find_last_not_of(const value_type* s, size_type pos = npos) const noexcept;
259    size_type find_last_not_of(value_type c, size_type pos = npos) const noexcept;
260
261    int compare(const basic_string& str) const noexcept;
262    int compare(size_type pos1, size_type n1, const basic_string& str) const;
263    int compare(size_type pos1, size_type n1, const basic_string& str,
264                size_type pos2, size_type n2=npos) const; // C++14
265    int compare(const value_type* s) const noexcept;
266    int compare(size_type pos1, size_type n1, const value_type* s) const;
267    int compare(size_type pos1, size_type n1, const value_type* s, size_type n2) const;
268
269    bool __invariants() const;
270};
271
272template<class charT, class traits, class Allocator>
273basic_string<charT, traits, Allocator>
274operator+(const basic_string<charT, traits, Allocator>& lhs,
275          const basic_string<charT, traits, Allocator>& rhs);
276
277template<class charT, class traits, class Allocator>
278basic_string<charT, traits, Allocator>
279operator+(const charT* lhs , const basic_string<charT,traits,Allocator>&rhs);
280
281template<class charT, class traits, class Allocator>
282basic_string<charT, traits, Allocator>
283operator+(charT lhs, const basic_string<charT,traits,Allocator>& rhs);
284
285template<class charT, class traits, class Allocator>
286basic_string<charT, traits, Allocator>
287operator+(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);
288
289template<class charT, class traits, class Allocator>
290basic_string<charT, traits, Allocator>
291operator+(const basic_string<charT, traits, Allocator>& lhs, charT rhs);
292
293template<class charT, class traits, class Allocator>
294bool operator==(const basic_string<charT, traits, Allocator>& lhs,
295                const basic_string<charT, traits, Allocator>& rhs) noexcept;
296
297template<class charT, class traits, class Allocator>
298bool operator==(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
299
300template<class charT, class traits, class Allocator>
301bool operator==(const basic_string<charT,traits,Allocator>& lhs, const charT* rhs) noexcept;
302
303template<class charT, class traits, class Allocator>
304bool operator!=(const basic_string<charT,traits,Allocator>& lhs,
305                const basic_string<charT, traits, Allocator>& rhs) noexcept;
306
307template<class charT, class traits, class Allocator>
308bool operator!=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
309
310template<class charT, class traits, class Allocator>
311bool operator!=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
312
313template<class charT, class traits, class Allocator>
314bool operator< (const basic_string<charT, traits, Allocator>& lhs,
315                const basic_string<charT, traits, Allocator>& rhs) noexcept;
316
317template<class charT, class traits, class Allocator>
318bool operator< (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
319
320template<class charT, class traits, class Allocator>
321bool operator< (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
322
323template<class charT, class traits, class Allocator>
324bool operator> (const basic_string<charT, traits, Allocator>& lhs,
325                const basic_string<charT, traits, Allocator>& rhs) noexcept;
326
327template<class charT, class traits, class Allocator>
328bool operator> (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
329
330template<class charT, class traits, class Allocator>
331bool operator> (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
332
333template<class charT, class traits, class Allocator>
334bool operator<=(const basic_string<charT, traits, Allocator>& lhs,
335                const basic_string<charT, traits, Allocator>& rhs) noexcept;
336
337template<class charT, class traits, class Allocator>
338bool operator<=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
339
340template<class charT, class traits, class Allocator>
341bool operator<=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
342
343template<class charT, class traits, class Allocator>
344bool operator>=(const basic_string<charT, traits, Allocator>& lhs,
345                const basic_string<charT, traits, Allocator>& rhs) noexcept;
346
347template<class charT, class traits, class Allocator>
348bool operator>=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
349
350template<class charT, class traits, class Allocator>
351bool operator>=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
352
353template<class charT, class traits, class Allocator>
354void swap(basic_string<charT, traits, Allocator>& lhs,
355          basic_string<charT, traits, Allocator>& rhs)
356            noexcept(noexcept(lhs.swap(rhs)));
357
358template<class charT, class traits, class Allocator>
359basic_istream<charT, traits>&
360operator>>(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
361
362template<class charT, class traits, class Allocator>
363basic_ostream<charT, traits>&
364operator<<(basic_ostream<charT, traits>& os, const basic_string<charT, traits, Allocator>& str);
365
366template<class charT, class traits, class Allocator>
367basic_istream<charT, traits>&
368getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str,
369        charT delim);
370
371template<class charT, class traits, class Allocator>
372basic_istream<charT, traits>&
373getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
374
375typedef basic_string<char>    string;
376typedef basic_string<wchar_t> wstring;
377typedef basic_string<char16_t> u16string;
378typedef basic_string<char32_t> u32string;
379
380int                stoi  (const string& str, size_t* idx = 0, int base = 10);
381long               stol  (const string& str, size_t* idx = 0, int base = 10);
382unsigned long      stoul (const string& str, size_t* idx = 0, int base = 10);
383long long          stoll (const string& str, size_t* idx = 0, int base = 10);
384unsigned long long stoull(const string& str, size_t* idx = 0, int base = 10);
385
386float       stof (const string& str, size_t* idx = 0);
387double      stod (const string& str, size_t* idx = 0);
388long double stold(const string& str, size_t* idx = 0);
389
390string to_string(int val);
391string to_string(unsigned val);
392string to_string(long val);
393string to_string(unsigned long val);
394string to_string(long long val);
395string to_string(unsigned long long val);
396string to_string(float val);
397string to_string(double val);
398string to_string(long double val);
399
400int                stoi  (const wstring& str, size_t* idx = 0, int base = 10);
401long               stol  (const wstring& str, size_t* idx = 0, int base = 10);
402unsigned long      stoul (const wstring& str, size_t* idx = 0, int base = 10);
403long long          stoll (const wstring& str, size_t* idx = 0, int base = 10);
404unsigned long long stoull(const wstring& str, size_t* idx = 0, int base = 10);
405
406float       stof (const wstring& str, size_t* idx = 0);
407double      stod (const wstring& str, size_t* idx = 0);
408long double stold(const wstring& str, size_t* idx = 0);
409
410wstring to_wstring(int val);
411wstring to_wstring(unsigned val);
412wstring to_wstring(long val);
413wstring to_wstring(unsigned long val);
414wstring to_wstring(long long val);
415wstring to_wstring(unsigned long long val);
416wstring to_wstring(float val);
417wstring to_wstring(double val);
418wstring to_wstring(long double val);
419
420template <> struct hash<string>;
421template <> struct hash<u16string>;
422template <> struct hash<u32string>;
423template <> struct hash<wstring>;
424
425basic_string<char>     operator "" s( const char *str,     size_t len ); // C++14
426basic_string<wchar_t>  operator "" s( const wchar_t *str,  size_t len ); // C++14
427basic_string<char16_t> operator "" s( const char16_t *str, size_t len ); // C++14
428basic_string<char32_t> operator "" s( const char32_t *str, size_t len ); // C++14
429
430}  // std
431
432*/
433
434#include <__config>
435#include <iosfwd>
436#include <cstring>
437#include <cstdio>  // For EOF.
438#include <cwchar>
439#include <algorithm>
440#include <iterator>
441#include <utility>
442#include <memory>
443#include <stdexcept>
444#include <type_traits>
445#include <initializer_list>
446#include <__functional_base>
447#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
448#include <cstdint>
449#endif
450#if defined(_LIBCPP_NO_EXCEPTIONS)
451#include <cassert>
452#endif
453
454#include <__undef_min_max>
455
456#include <__debug>
457
458#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
459#pragma GCC system_header
460#endif
461
462_LIBCPP_BEGIN_NAMESPACE_STD
463
464// fpos
465
466template <class _StateT>
467class _LIBCPP_TYPE_VIS_ONLY fpos
468{
469private:
470    _StateT __st_;
471    streamoff __off_;
472public:
473    _LIBCPP_INLINE_VISIBILITY fpos(streamoff __off = streamoff()) : __st_(), __off_(__off) {}
474
475    _LIBCPP_INLINE_VISIBILITY operator streamoff() const {return __off_;}
476
477    _LIBCPP_INLINE_VISIBILITY _StateT state() const {return __st_;}
478    _LIBCPP_INLINE_VISIBILITY void state(_StateT __st) {__st_ = __st;}
479
480    _LIBCPP_INLINE_VISIBILITY fpos& operator+=(streamoff __off) {__off_ += __off; return *this;}
481    _LIBCPP_INLINE_VISIBILITY fpos  operator+ (streamoff __off) const {fpos __t(*this); __t += __off; return __t;}
482    _LIBCPP_INLINE_VISIBILITY fpos& operator-=(streamoff __off) {__off_ -= __off; return *this;}
483    _LIBCPP_INLINE_VISIBILITY fpos  operator- (streamoff __off) const {fpos __t(*this); __t -= __off; return __t;}
484};
485
486template <class _StateT>
487inline _LIBCPP_INLINE_VISIBILITY
488streamoff operator-(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
489    {return streamoff(__x) - streamoff(__y);}
490
491template <class _StateT>
492inline _LIBCPP_INLINE_VISIBILITY
493bool operator==(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
494    {return streamoff(__x) == streamoff(__y);}
495
496template <class _StateT>
497inline _LIBCPP_INLINE_VISIBILITY
498bool operator!=(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
499    {return streamoff(__x) != streamoff(__y);}
500
501// char_traits
502
503template <class _CharT>
504struct _LIBCPP_TYPE_VIS_ONLY char_traits
505{
506    typedef _CharT    char_type;
507    typedef int       int_type;
508    typedef streamoff off_type;
509    typedef streampos pos_type;
510    typedef mbstate_t state_type;
511
512    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
513        {__c1 = __c2;}
514    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
515        {return __c1 == __c2;}
516    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
517        {return __c1 < __c2;}
518
519    static int              compare(const char_type* __s1, const char_type* __s2, size_t __n);
520    static size_t           length(const char_type* __s);
521    static const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
522    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
523    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
524    static char_type*       assign(char_type* __s, size_t __n, char_type __a);
525
526    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
527        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
528    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
529        {return char_type(__c);}
530    static inline _LIBCPP_CONSTEXPR int_type  to_int_type(char_type __c) _NOEXCEPT
531        {return int_type(__c);}
532    static inline _LIBCPP_CONSTEXPR bool      eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
533        {return __c1 == __c2;}
534    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
535        {return int_type(EOF);}
536};
537
538template <class _CharT>
539int
540char_traits<_CharT>::compare(const char_type* __s1, const char_type* __s2, size_t __n)
541{
542    for (; __n; --__n, ++__s1, ++__s2)
543    {
544        if (lt(*__s1, *__s2))
545            return -1;
546        if (lt(*__s2, *__s1))
547            return 1;
548    }
549    return 0;
550}
551
552template <class _CharT>
553inline _LIBCPP_INLINE_VISIBILITY
554size_t
555char_traits<_CharT>::length(const char_type* __s)
556{
557    size_t __len = 0;
558    for (; !eq(*__s, char_type(0)); ++__s)
559        ++__len;
560    return __len;
561}
562
563template <class _CharT>
564inline _LIBCPP_INLINE_VISIBILITY
565const _CharT*
566char_traits<_CharT>::find(const char_type* __s, size_t __n, const char_type& __a)
567{
568    for (; __n; --__n)
569    {
570        if (eq(*__s, __a))
571            return __s;
572        ++__s;
573    }
574    return 0;
575}
576
577template <class _CharT>
578_CharT*
579char_traits<_CharT>::move(char_type* __s1, const char_type* __s2, size_t __n)
580{
581    char_type* __r = __s1;
582    if (__s1 < __s2)
583    {
584        for (; __n; --__n, ++__s1, ++__s2)
585            assign(*__s1, *__s2);
586    }
587    else if (__s2 < __s1)
588    {
589        __s1 += __n;
590        __s2 += __n;
591        for (; __n; --__n)
592            assign(*--__s1, *--__s2);
593    }
594    return __r;
595}
596
597template <class _CharT>
598inline _LIBCPP_INLINE_VISIBILITY
599_CharT*
600char_traits<_CharT>::copy(char_type* __s1, const char_type* __s2, size_t __n)
601{
602    _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
603    char_type* __r = __s1;
604    for (; __n; --__n, ++__s1, ++__s2)
605        assign(*__s1, *__s2);
606    return __r;
607}
608
609template <class _CharT>
610inline _LIBCPP_INLINE_VISIBILITY
611_CharT*
612char_traits<_CharT>::assign(char_type* __s, size_t __n, char_type __a)
613{
614    char_type* __r = __s;
615    for (; __n; --__n, ++__s)
616        assign(*__s, __a);
617    return __r;
618}
619
620// char_traits<char>
621
622template <>
623struct _LIBCPP_TYPE_VIS_ONLY char_traits<char>
624{
625    typedef char      char_type;
626    typedef int       int_type;
627    typedef streamoff off_type;
628    typedef streampos pos_type;
629    typedef mbstate_t state_type;
630
631    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
632        {__c1 = __c2;}
633    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
634            {return __c1 == __c2;}
635    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
636        {return (unsigned char)__c1 < (unsigned char)__c2;}
637
638    static inline int compare(const char_type* __s1, const char_type* __s2, size_t __n)
639        {return __n == 0 ? 0 : memcmp(__s1, __s2, __n);}
640    static inline size_t length(const char_type* __s) {return strlen(__s);}
641    static inline const char_type* find(const char_type* __s, size_t __n, const char_type& __a)
642        {return __n == 0 ? NULL : (const char_type*) memchr(__s, to_int_type(__a), __n);}
643    static inline char_type* move(char_type* __s1, const char_type* __s2, size_t __n)
644        {return __n == 0 ? __s1 : (char_type*) memmove(__s1, __s2, __n);}
645    static inline char_type* copy(char_type* __s1, const char_type* __s2, size_t __n)
646        {
647            _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
648            return __n == 0 ? __s1 : (char_type*)memcpy(__s1, __s2, __n);
649        }
650    static inline char_type* assign(char_type* __s, size_t __n, char_type __a)
651        {return __n == 0 ? __s : (char_type*)memset(__s, to_int_type(__a), __n);}
652
653    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
654        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
655    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
656        {return char_type(__c);}
657    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
658        {return int_type((unsigned char)__c);}
659    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
660        {return __c1 == __c2;}
661    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
662        {return int_type(EOF);}
663};
664
665// char_traits<wchar_t>
666
667template <>
668struct _LIBCPP_TYPE_VIS_ONLY char_traits<wchar_t>
669{
670    typedef wchar_t   char_type;
671    typedef wint_t    int_type;
672    typedef streamoff off_type;
673    typedef streampos pos_type;
674    typedef mbstate_t state_type;
675
676    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
677        {__c1 = __c2;}
678    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
679        {return __c1 == __c2;}
680    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
681        {return __c1 < __c2;}
682
683    static inline int compare(const char_type* __s1, const char_type* __s2, size_t __n)
684        {return __n == 0 ? 0 : wmemcmp(__s1, __s2, __n);}
685    static inline size_t length(const char_type* __s)
686        {return wcslen(__s);}
687    static inline const char_type* find(const char_type* __s, size_t __n, const char_type& __a)
688        {return __n == 0 ? NULL : (const char_type*)wmemchr(__s, __a, __n);}
689    static inline char_type* move(char_type* __s1, const char_type* __s2, size_t __n)
690        {return __n == 0 ? __s1 : (char_type*)wmemmove(__s1, __s2, __n);}
691    static inline char_type* copy(char_type* __s1, const char_type* __s2, size_t __n)
692        {
693            _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
694            return __n == 0 ? __s1 : (char_type*)wmemcpy(__s1, __s2, __n);
695        }
696    static inline char_type* assign(char_type* __s, size_t __n, char_type __a)
697        {return __n == 0 ? __s : (char_type*)wmemset(__s, __a, __n);}
698
699    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
700        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
701    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
702        {return char_type(__c);}
703    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
704        {return int_type(__c);}
705    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
706        {return __c1 == __c2;}
707    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
708        {return int_type(WEOF);}
709};
710
711#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
712
713template <>
714struct _LIBCPP_TYPE_VIS_ONLY char_traits<char16_t>
715{
716    typedef char16_t       char_type;
717    typedef uint_least16_t int_type;
718    typedef streamoff      off_type;
719    typedef u16streampos   pos_type;
720    typedef mbstate_t      state_type;
721
722    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
723        {__c1 = __c2;}
724    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
725        {return __c1 == __c2;}
726    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
727        {return __c1 < __c2;}
728
729    static int              compare(const char_type* __s1, const char_type* __s2, size_t __n);
730    static size_t           length(const char_type* __s);
731    static const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
732    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
733    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
734    static char_type*       assign(char_type* __s, size_t __n, char_type __a);
735
736    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
737        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
738    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
739        {return char_type(__c);}
740    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
741        {return int_type(__c);}
742    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
743        {return __c1 == __c2;}
744    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
745        {return int_type(0xFFFF);}
746};
747
748inline _LIBCPP_INLINE_VISIBILITY
749int
750char_traits<char16_t>::compare(const char_type* __s1, const char_type* __s2, size_t __n)
751{
752    for (; __n; --__n, ++__s1, ++__s2)
753    {
754        if (lt(*__s1, *__s2))
755            return -1;
756        if (lt(*__s2, *__s1))
757            return 1;
758    }
759    return 0;
760}
761
762inline _LIBCPP_INLINE_VISIBILITY
763size_t
764char_traits<char16_t>::length(const char_type* __s)
765{
766    size_t __len = 0;
767    for (; !eq(*__s, char_type(0)); ++__s)
768        ++__len;
769    return __len;
770}
771
772inline _LIBCPP_INLINE_VISIBILITY
773const char16_t*
774char_traits<char16_t>::find(const char_type* __s, size_t __n, const char_type& __a)
775{
776    for (; __n; --__n)
777    {
778        if (eq(*__s, __a))
779            return __s;
780        ++__s;
781    }
782    return 0;
783}
784
785inline _LIBCPP_INLINE_VISIBILITY
786char16_t*
787char_traits<char16_t>::move(char_type* __s1, const char_type* __s2, size_t __n)
788{
789    char_type* __r = __s1;
790    if (__s1 < __s2)
791    {
792        for (; __n; --__n, ++__s1, ++__s2)
793            assign(*__s1, *__s2);
794    }
795    else if (__s2 < __s1)
796    {
797        __s1 += __n;
798        __s2 += __n;
799        for (; __n; --__n)
800            assign(*--__s1, *--__s2);
801    }
802    return __r;
803}
804
805inline _LIBCPP_INLINE_VISIBILITY
806char16_t*
807char_traits<char16_t>::copy(char_type* __s1, const char_type* __s2, size_t __n)
808{
809    _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
810    char_type* __r = __s1;
811    for (; __n; --__n, ++__s1, ++__s2)
812        assign(*__s1, *__s2);
813    return __r;
814}
815
816inline _LIBCPP_INLINE_VISIBILITY
817char16_t*
818char_traits<char16_t>::assign(char_type* __s, size_t __n, char_type __a)
819{
820    char_type* __r = __s;
821    for (; __n; --__n, ++__s)
822        assign(*__s, __a);
823    return __r;
824}
825
826template <>
827struct _LIBCPP_TYPE_VIS_ONLY char_traits<char32_t>
828{
829    typedef char32_t       char_type;
830    typedef uint_least32_t int_type;
831    typedef streamoff      off_type;
832    typedef u32streampos   pos_type;
833    typedef mbstate_t      state_type;
834
835    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
836        {__c1 = __c2;}
837    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
838        {return __c1 == __c2;}
839    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
840        {return __c1 < __c2;}
841
842    static int              compare(const char_type* __s1, const char_type* __s2, size_t __n);
843    static size_t           length(const char_type* __s);
844    static const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
845    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
846    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
847    static char_type*       assign(char_type* __s, size_t __n, char_type __a);
848
849    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
850        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
851    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
852        {return char_type(__c);}
853    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
854        {return int_type(__c);}
855    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
856        {return __c1 == __c2;}
857    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
858        {return int_type(0xFFFFFFFF);}
859};
860
861inline _LIBCPP_INLINE_VISIBILITY
862int
863char_traits<char32_t>::compare(const char_type* __s1, const char_type* __s2, size_t __n)
864{
865    for (; __n; --__n, ++__s1, ++__s2)
866    {
867        if (lt(*__s1, *__s2))
868            return -1;
869        if (lt(*__s2, *__s1))
870            return 1;
871    }
872    return 0;
873}
874
875inline _LIBCPP_INLINE_VISIBILITY
876size_t
877char_traits<char32_t>::length(const char_type* __s)
878{
879    size_t __len = 0;
880    for (; !eq(*__s, char_type(0)); ++__s)
881        ++__len;
882    return __len;
883}
884
885inline _LIBCPP_INLINE_VISIBILITY
886const char32_t*
887char_traits<char32_t>::find(const char_type* __s, size_t __n, const char_type& __a)
888{
889    for (; __n; --__n)
890    {
891        if (eq(*__s, __a))
892            return __s;
893        ++__s;
894    }
895    return 0;
896}
897
898inline _LIBCPP_INLINE_VISIBILITY
899char32_t*
900char_traits<char32_t>::move(char_type* __s1, const char_type* __s2, size_t __n)
901{
902    char_type* __r = __s1;
903    if (__s1 < __s2)
904    {
905        for (; __n; --__n, ++__s1, ++__s2)
906            assign(*__s1, *__s2);
907    }
908    else if (__s2 < __s1)
909    {
910        __s1 += __n;
911        __s2 += __n;
912        for (; __n; --__n)
913            assign(*--__s1, *--__s2);
914    }
915    return __r;
916}
917
918inline _LIBCPP_INLINE_VISIBILITY
919char32_t*
920char_traits<char32_t>::copy(char_type* __s1, const char_type* __s2, size_t __n)
921{
922    _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
923    char_type* __r = __s1;
924    for (; __n; --__n, ++__s1, ++__s2)
925        assign(*__s1, *__s2);
926    return __r;
927}
928
929inline _LIBCPP_INLINE_VISIBILITY
930char32_t*
931char_traits<char32_t>::assign(char_type* __s, size_t __n, char_type __a)
932{
933    char_type* __r = __s;
934    for (; __n; --__n, ++__s)
935        assign(*__s, __a);
936    return __r;
937}
938
939#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
940
941// helper fns for basic_string
942
943// __str_find
944template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
945_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
946__str_find(const _CharT *__p, _SizeT __sz,
947             _CharT __c, _SizeT __pos) _NOEXCEPT
948{
949    if (__pos >= __sz)
950        return __npos;
951    const _CharT* __r = _Traits::find(__p + __pos, __sz - __pos, __c);
952    if (__r == 0)
953        return __npos;
954    return static_cast<_SizeT>(__r - __p);
955}
956
957template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
958_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
959__str_find(const _CharT *__p, _SizeT __sz,
960       const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
961{
962    if (__pos > __sz || __sz - __pos < __n)
963        return __npos;
964    if (__n == 0)
965        return __pos;
966    const _CharT* __r =
967        _VSTD::__search(__p + __pos, __p + __sz,
968                        __s, __s + __n, _Traits::eq,
969                        random_access_iterator_tag(), random_access_iterator_tag());
970    if (__r == __p + __sz)
971        return __npos;
972    return static_cast<_SizeT>(__r - __p);
973}
974
975
976// __str_rfind
977
978template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
979_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
980__str_rfind(const _CharT *__p, _SizeT __sz,
981              _CharT __c, _SizeT __pos) _NOEXCEPT
982{
983    if (__sz < 1)
984        return __npos;
985    if (__pos < __sz)
986        ++__pos;
987    else
988        __pos = __sz;
989    for (const _CharT* __ps = __p + __pos; __ps != __p;)
990    {
991        if (_Traits::eq(*--__ps, __c))
992            return static_cast<_SizeT>(__ps - __p);
993    }
994    return __npos;
995}
996
997template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
998_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
999__str_rfind(const _CharT *__p, _SizeT __sz,
1000        const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1001{
1002    __pos = _VSTD::min(__pos, __sz);
1003    if (__n < __sz - __pos)
1004        __pos += __n;
1005    else
1006        __pos = __sz;
1007    const _CharT* __r = _VSTD::__find_end(
1008                  __p, __p + __pos, __s, __s + __n, _Traits::eq,
1009                        random_access_iterator_tag(), random_access_iterator_tag());
1010    if (__n > 0 && __r == __p + __pos)
1011        return __npos;
1012    return static_cast<_SizeT>(__r - __p);
1013}
1014
1015// __str_find_first_of
1016template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1017_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1018__str_find_first_of(const _CharT *__p, _SizeT __sz,
1019                const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1020{
1021    if (__pos >= __sz || __n == 0)
1022        return __npos;
1023    const _CharT* __r = _VSTD::__find_first_of_ce
1024        (__p + __pos, __p + __sz, __s, __s + __n, _Traits::eq );
1025    if (__r == __p + __sz)
1026        return __npos;
1027    return static_cast<_SizeT>(__r - __p);
1028}
1029
1030
1031// __str_find_last_of
1032template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1033_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1034__str_find_last_of(const _CharT *__p, _SizeT __sz,
1035               const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1036    {
1037    if (__n != 0)
1038    {
1039        if (__pos < __sz)
1040            ++__pos;
1041        else
1042            __pos = __sz;
1043        for (const _CharT* __ps = __p + __pos; __ps != __p;)
1044        {
1045            const _CharT* __r = _Traits::find(__s, __n, *--__ps);
1046            if (__r)
1047                return static_cast<_SizeT>(__ps - __p);
1048        }
1049    }
1050    return __npos;
1051}
1052
1053
1054// __str_find_first_not_of
1055template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1056_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1057__str_find_first_not_of(const _CharT *__p, _SizeT __sz,
1058                    const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1059{
1060    if (__pos < __sz)
1061    {
1062        const _CharT* __pe = __p + __sz;
1063        for (const _CharT* __ps = __p + __pos; __ps != __pe; ++__ps)
1064            if (_Traits::find(__s, __n, *__ps) == 0)
1065                return static_cast<_SizeT>(__ps - __p);
1066    }
1067    return __npos;
1068}
1069
1070
1071template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1072_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1073__str_find_first_not_of(const _CharT *__p, _SizeT __sz,
1074                          _CharT __c, _SizeT __pos) _NOEXCEPT
1075{
1076    if (__pos < __sz)
1077    {
1078        const _CharT* __pe = __p + __sz;
1079        for (const _CharT* __ps = __p + __pos; __ps != __pe; ++__ps)
1080            if (!_Traits::eq(*__ps, __c))
1081                return static_cast<_SizeT>(__ps - __p);
1082    }
1083    return __npos;
1084}
1085
1086
1087// __str_find_last_not_of
1088template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1089_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1090__str_find_last_not_of(const _CharT *__p, _SizeT __sz,
1091                   const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1092{
1093    if (__pos < __sz)
1094        ++__pos;
1095    else
1096        __pos = __sz;
1097    for (const _CharT* __ps = __p + __pos; __ps != __p;)
1098        if (_Traits::find(__s, __n, *--__ps) == 0)
1099            return static_cast<_SizeT>(__ps - __p);
1100    return __npos;
1101}
1102
1103
1104template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1105_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1106__str_find_last_not_of(const _CharT *__p, _SizeT __sz,
1107                         _CharT __c, _SizeT __pos) _NOEXCEPT
1108{
1109    if (__pos < __sz)
1110        ++__pos;
1111    else
1112        __pos = __sz;
1113    for (const _CharT* __ps = __p + __pos; __ps != __p;)
1114        if (!_Traits::eq(*--__ps, __c))
1115            return static_cast<_SizeT>(__ps - __p);
1116    return __npos;
1117}
1118
1119template<class _Ptr>
1120size_t _LIBCPP_INLINE_VISIBILITY __do_string_hash(_Ptr __p, _Ptr __e)
1121{
1122    typedef typename iterator_traits<_Ptr>::value_type value_type;
1123    return __murmur2_or_cityhash<size_t>()(__p, (__e-__p)*sizeof(value_type));
1124}
1125
1126// basic_string
1127
1128template<class _CharT, class _Traits, class _Allocator>
1129basic_string<_CharT, _Traits, _Allocator>
1130operator+(const basic_string<_CharT, _Traits, _Allocator>& __x,
1131          const basic_string<_CharT, _Traits, _Allocator>& __y);
1132
1133template<class _CharT, class _Traits, class _Allocator>
1134basic_string<_CharT, _Traits, _Allocator>
1135operator+(const _CharT* __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
1136
1137template<class _CharT, class _Traits, class _Allocator>
1138basic_string<_CharT, _Traits, _Allocator>
1139operator+(_CharT __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
1140
1141template<class _CharT, class _Traits, class _Allocator>
1142basic_string<_CharT, _Traits, _Allocator>
1143operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, const _CharT* __y);
1144
1145template<class _CharT, class _Traits, class _Allocator>
1146basic_string<_CharT, _Traits, _Allocator>
1147operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, _CharT __y);
1148
1149template <bool>
1150class _LIBCPP_TYPE_VIS_ONLY __basic_string_common
1151{
1152protected:
1153    void __throw_length_error() const;
1154    void __throw_out_of_range() const;
1155};
1156
1157template <bool __b>
1158void
1159__basic_string_common<__b>::__throw_length_error() const
1160{
1161#ifndef _LIBCPP_NO_EXCEPTIONS
1162    throw length_error("basic_string");
1163#else
1164    assert(!"basic_string length_error");
1165#endif
1166}
1167
1168template <bool __b>
1169void
1170__basic_string_common<__b>::__throw_out_of_range() const
1171{
1172#ifndef _LIBCPP_NO_EXCEPTIONS
1173    throw out_of_range("basic_string");
1174#else
1175    assert(!"basic_string out_of_range");
1176#endif
1177}
1178
1179#ifdef _LIBCPP_MSVC
1180#pragma warning( push )
1181#pragma warning( disable: 4231 )
1182#endif // _LIBCPP_MSVC
1183_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS __basic_string_common<true>)
1184#ifdef _LIBCPP_MSVC
1185#pragma warning( pop )
1186#endif // _LIBCPP_MSVC
1187
1188#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1189
1190template <class _CharT, size_t = sizeof(_CharT)>
1191struct __padding
1192{
1193    unsigned char __xx[sizeof(_CharT)-1];
1194};
1195
1196template <class _CharT>
1197struct __padding<_CharT, 1>
1198{
1199};
1200
1201#endif  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1202
1203template<class _CharT, class _Traits, class _Allocator>
1204class _LIBCPP_TYPE_VIS_ONLY basic_string
1205    : private __basic_string_common<true>
1206{
1207public:
1208    typedef basic_string                                 __self;
1209    typedef _Traits                                      traits_type;
1210    typedef typename traits_type::char_type              value_type;
1211    typedef _Allocator                                   allocator_type;
1212    typedef allocator_traits<allocator_type>             __alloc_traits;
1213    typedef typename __alloc_traits::size_type           size_type;
1214    typedef typename __alloc_traits::difference_type     difference_type;
1215    typedef value_type&                                  reference;
1216    typedef const value_type&                            const_reference;
1217    typedef typename __alloc_traits::pointer             pointer;
1218    typedef typename __alloc_traits::const_pointer       const_pointer;
1219
1220    static_assert(is_pod<value_type>::value, "Character type of basic_string must be a POD");
1221    static_assert((is_same<_CharT, value_type>::value),
1222                  "traits_type::char_type must be the same type as CharT");
1223    static_assert((is_same<typename allocator_type::value_type, value_type>::value),
1224                  "Allocator::value_type must be same type as value_type");
1225#if defined(_LIBCPP_RAW_ITERATORS)
1226    typedef pointer                                      iterator;
1227    typedef const_pointer                                const_iterator;
1228#else  // defined(_LIBCPP_RAW_ITERATORS)
1229    typedef __wrap_iter<pointer>                         iterator;
1230    typedef __wrap_iter<const_pointer>                   const_iterator;
1231#endif  // defined(_LIBCPP_RAW_ITERATORS)
1232    typedef _VSTD::reverse_iterator<iterator>             reverse_iterator;
1233    typedef _VSTD::reverse_iterator<const_iterator>       const_reverse_iterator;
1234
1235private:
1236
1237#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1238
1239    struct __long
1240    {
1241        pointer   __data_;
1242        size_type __size_;
1243        size_type __cap_;
1244    };
1245
1246#if _LIBCPP_BIG_ENDIAN
1247    enum {__short_mask = 0x01};
1248    enum {__long_mask  = 0x1ul};
1249#else  // _LIBCPP_BIG_ENDIAN
1250    enum {__short_mask = 0x80};
1251    enum {__long_mask  = ~(size_type(~0) >> 1)};
1252#endif  // _LIBCPP_BIG_ENDIAN
1253
1254    enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
1255                      (sizeof(__long) - 1)/sizeof(value_type) : 2};
1256
1257    struct __short
1258    {
1259        value_type __data_[__min_cap];
1260        struct
1261            : __padding<value_type>
1262        {
1263            unsigned char __size_;
1264        };
1265    };
1266
1267#else
1268
1269    struct __long
1270    {
1271        size_type __cap_;
1272        size_type __size_;
1273        pointer   __data_;
1274    };
1275
1276#if _LIBCPP_BIG_ENDIAN
1277    enum {__short_mask = 0x80};
1278    enum {__long_mask  = ~(size_type(~0) >> 1)};
1279#else  // _LIBCPP_BIG_ENDIAN
1280    enum {__short_mask = 0x01};
1281    enum {__long_mask  = 0x1ul};
1282#endif  // _LIBCPP_BIG_ENDIAN
1283
1284    enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
1285                      (sizeof(__long) - 1)/sizeof(value_type) : 2};
1286
1287    struct __short
1288    {
1289        union
1290        {
1291            unsigned char __size_;
1292            value_type __lx;
1293        };
1294        value_type __data_[__min_cap];
1295    };
1296
1297#endif  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1298
1299    union __ulx{__long __lx; __short __lxx;};
1300
1301    enum {__n_words = sizeof(__ulx) / sizeof(size_type)};
1302
1303    struct __raw
1304    {
1305        size_type __words[__n_words];
1306    };
1307
1308    struct __rep
1309    {
1310        union
1311        {
1312            __long  __l;
1313            __short __s;
1314            __raw   __r;
1315        };
1316    };
1317
1318    __compressed_pair<__rep, allocator_type> __r_;
1319
1320public:
1321    static const size_type npos = -1;
1322
1323    _LIBCPP_INLINE_VISIBILITY basic_string()
1324        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value);
1325
1326    _LIBCPP_INLINE_VISIBILITY explicit basic_string(const allocator_type& __a)
1327#if _LIBCPP_STD_VER <= 14
1328        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value);
1329#else
1330        _NOEXCEPT;
1331#endif
1332
1333    basic_string(const basic_string& __str);
1334    basic_string(const basic_string& __str, const allocator_type& __a);
1335
1336#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1337    _LIBCPP_INLINE_VISIBILITY
1338    basic_string(basic_string&& __str)
1339#if _LIBCPP_STD_VER <= 14
1340        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
1341#else
1342        _NOEXCEPT;
1343#endif
1344
1345    _LIBCPP_INLINE_VISIBILITY
1346    basic_string(basic_string&& __str, const allocator_type& __a);
1347#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
1348    _LIBCPP_INLINE_VISIBILITY basic_string(const value_type* __s);
1349    _LIBCPP_INLINE_VISIBILITY
1350    basic_string(const value_type* __s, const allocator_type& __a);
1351    _LIBCPP_INLINE_VISIBILITY
1352    basic_string(const value_type* __s, size_type __n);
1353    _LIBCPP_INLINE_VISIBILITY
1354    basic_string(const value_type* __s, size_type __n, const allocator_type& __a);
1355    _LIBCPP_INLINE_VISIBILITY
1356    basic_string(size_type __n, value_type __c);
1357    _LIBCPP_INLINE_VISIBILITY
1358    basic_string(size_type __n, value_type __c, const allocator_type& __a);
1359    basic_string(const basic_string& __str, size_type __pos, size_type __n = npos,
1360                 const allocator_type& __a = allocator_type());
1361    template<class _InputIterator>
1362        _LIBCPP_INLINE_VISIBILITY
1363        basic_string(_InputIterator __first, _InputIterator __last);
1364    template<class _InputIterator>
1365        _LIBCPP_INLINE_VISIBILITY
1366        basic_string(_InputIterator __first, _InputIterator __last, const allocator_type& __a);
1367#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1368    _LIBCPP_INLINE_VISIBILITY
1369    basic_string(initializer_list<value_type> __il);
1370    _LIBCPP_INLINE_VISIBILITY
1371    basic_string(initializer_list<value_type> __il, const allocator_type& __a);
1372#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1373
1374    ~basic_string();
1375
1376    basic_string& operator=(const basic_string& __str);
1377#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1378    _LIBCPP_INLINE_VISIBILITY
1379    basic_string& operator=(basic_string&& __str)
1380        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value));
1381#endif
1382    _LIBCPP_INLINE_VISIBILITY basic_string& operator=(const value_type* __s) {return assign(__s);}
1383    basic_string& operator=(value_type __c);
1384#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1385    _LIBCPP_INLINE_VISIBILITY
1386    basic_string& operator=(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
1387#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1388
1389#if _LIBCPP_DEBUG_LEVEL >= 2
1390    _LIBCPP_INLINE_VISIBILITY
1391    iterator begin() _NOEXCEPT
1392        {return iterator(this, __get_pointer());}
1393    _LIBCPP_INLINE_VISIBILITY
1394    const_iterator begin() const _NOEXCEPT
1395        {return const_iterator(this, __get_pointer());}
1396    _LIBCPP_INLINE_VISIBILITY
1397    iterator end() _NOEXCEPT
1398        {return iterator(this, __get_pointer() + size());}
1399    _LIBCPP_INLINE_VISIBILITY
1400    const_iterator end() const _NOEXCEPT
1401        {return const_iterator(this, __get_pointer() + size());}
1402#else
1403    _LIBCPP_INLINE_VISIBILITY
1404    iterator begin() _NOEXCEPT
1405        {return iterator(__get_pointer());}
1406    _LIBCPP_INLINE_VISIBILITY
1407    const_iterator begin() const _NOEXCEPT
1408        {return const_iterator(__get_pointer());}
1409    _LIBCPP_INLINE_VISIBILITY
1410    iterator end() _NOEXCEPT
1411        {return iterator(__get_pointer() + size());}
1412    _LIBCPP_INLINE_VISIBILITY
1413    const_iterator end() const _NOEXCEPT
1414        {return const_iterator(__get_pointer() + size());}
1415#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1416    _LIBCPP_INLINE_VISIBILITY
1417    reverse_iterator rbegin() _NOEXCEPT
1418        {return reverse_iterator(end());}
1419    _LIBCPP_INLINE_VISIBILITY
1420    const_reverse_iterator rbegin() const _NOEXCEPT
1421        {return const_reverse_iterator(end());}
1422    _LIBCPP_INLINE_VISIBILITY
1423    reverse_iterator rend() _NOEXCEPT
1424        {return reverse_iterator(begin());}
1425    _LIBCPP_INLINE_VISIBILITY
1426    const_reverse_iterator rend() const _NOEXCEPT
1427        {return const_reverse_iterator(begin());}
1428
1429    _LIBCPP_INLINE_VISIBILITY
1430    const_iterator cbegin() const _NOEXCEPT
1431        {return begin();}
1432    _LIBCPP_INLINE_VISIBILITY
1433    const_iterator cend() const _NOEXCEPT
1434        {return end();}
1435    _LIBCPP_INLINE_VISIBILITY
1436    const_reverse_iterator crbegin() const _NOEXCEPT
1437        {return rbegin();}
1438    _LIBCPP_INLINE_VISIBILITY
1439    const_reverse_iterator crend() const _NOEXCEPT
1440        {return rend();}
1441
1442    _LIBCPP_INLINE_VISIBILITY size_type size() const _NOEXCEPT
1443        {return __is_long() ? __get_long_size() : __get_short_size();}
1444    _LIBCPP_INLINE_VISIBILITY size_type length() const _NOEXCEPT {return size();}
1445    _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT;
1446    _LIBCPP_INLINE_VISIBILITY size_type capacity() const _NOEXCEPT
1447        {return (__is_long() ? __get_long_cap()
1448                             : static_cast<size_type>(__min_cap)) - 1;}
1449
1450    void resize(size_type __n, value_type __c);
1451    _LIBCPP_INLINE_VISIBILITY void resize(size_type __n) {resize(__n, value_type());}
1452
1453    void reserve(size_type res_arg = 0);
1454    _LIBCPP_INLINE_VISIBILITY
1455    void shrink_to_fit() _NOEXCEPT {reserve();}
1456    _LIBCPP_INLINE_VISIBILITY
1457    void clear() _NOEXCEPT;
1458    _LIBCPP_INLINE_VISIBILITY bool empty() const _NOEXCEPT {return size() == 0;}
1459
1460    _LIBCPP_INLINE_VISIBILITY const_reference operator[](size_type __pos) const;
1461    _LIBCPP_INLINE_VISIBILITY reference       operator[](size_type __pos);
1462
1463    const_reference at(size_type __n) const;
1464    reference       at(size_type __n);
1465
1466    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(const basic_string& __str) {return append(__str);}
1467    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(const value_type* __s)         {return append(__s);}
1468    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(value_type __c)            {push_back(__c); return *this;}
1469#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1470    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(initializer_list<value_type> __il) {return append(__il);}
1471#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1472
1473    _LIBCPP_INLINE_VISIBILITY
1474    basic_string& append(const basic_string& __str);
1475    basic_string& append(const basic_string& __str, size_type __pos, size_type __n=npos);
1476    basic_string& append(const value_type* __s, size_type __n);
1477    basic_string& append(const value_type* __s);
1478    basic_string& append(size_type __n, value_type __c);
1479    template<class _InputIterator>
1480        typename enable_if
1481        <
1482             __is_input_iterator  <_InputIterator>::value &&
1483            !__is_forward_iterator<_InputIterator>::value,
1484            basic_string&
1485        >::type
1486        append(_InputIterator __first, _InputIterator __last);
1487    template<class _ForwardIterator>
1488        typename enable_if
1489        <
1490            __is_forward_iterator<_ForwardIterator>::value,
1491            basic_string&
1492        >::type
1493        append(_ForwardIterator __first, _ForwardIterator __last);
1494#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1495    _LIBCPP_INLINE_VISIBILITY
1496    basic_string& append(initializer_list<value_type> __il) {return append(__il.begin(), __il.size());}
1497#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1498
1499    void push_back(value_type __c);
1500    _LIBCPP_INLINE_VISIBILITY
1501    void pop_back();
1502    _LIBCPP_INLINE_VISIBILITY reference       front();
1503    _LIBCPP_INLINE_VISIBILITY const_reference front() const;
1504    _LIBCPP_INLINE_VISIBILITY reference       back();
1505    _LIBCPP_INLINE_VISIBILITY const_reference back() const;
1506
1507    _LIBCPP_INLINE_VISIBILITY
1508    basic_string& assign(const basic_string& __str);
1509#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1510    _LIBCPP_INLINE_VISIBILITY
1511    basic_string& assign(basic_string&& str)
1512        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
1513        {*this = _VSTD::move(str); return *this;}
1514#endif
1515    basic_string& assign(const basic_string& __str, size_type __pos, size_type __n=npos);
1516    basic_string& assign(const value_type* __s, size_type __n);
1517    basic_string& assign(const value_type* __s);
1518    basic_string& assign(size_type __n, value_type __c);
1519    template<class _InputIterator>
1520        typename enable_if
1521        <
1522             __is_input_iterator  <_InputIterator>::value &&
1523            !__is_forward_iterator<_InputIterator>::value,
1524            basic_string&
1525        >::type
1526        assign(_InputIterator __first, _InputIterator __last);
1527    template<class _ForwardIterator>
1528        typename enable_if
1529        <
1530            __is_forward_iterator<_ForwardIterator>::value,
1531            basic_string&
1532        >::type
1533        assign(_ForwardIterator __first, _ForwardIterator __last);
1534#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1535    _LIBCPP_INLINE_VISIBILITY
1536    basic_string& assign(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
1537#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1538
1539    _LIBCPP_INLINE_VISIBILITY
1540    basic_string& insert(size_type __pos1, const basic_string& __str);
1541    basic_string& insert(size_type __pos1, const basic_string& __str, size_type __pos2, size_type __n=npos);
1542    basic_string& insert(size_type __pos, const value_type* __s, size_type __n);
1543    basic_string& insert(size_type __pos, const value_type* __s);
1544    basic_string& insert(size_type __pos, size_type __n, value_type __c);
1545    iterator      insert(const_iterator __pos, value_type __c);
1546    _LIBCPP_INLINE_VISIBILITY
1547    iterator      insert(const_iterator __pos, size_type __n, value_type __c);
1548    template<class _InputIterator>
1549        typename enable_if
1550        <
1551             __is_input_iterator  <_InputIterator>::value &&
1552            !__is_forward_iterator<_InputIterator>::value,
1553            iterator
1554        >::type
1555        insert(const_iterator __pos, _InputIterator __first, _InputIterator __last);
1556    template<class _ForwardIterator>
1557        typename enable_if
1558        <
1559            __is_forward_iterator<_ForwardIterator>::value,
1560            iterator
1561        >::type
1562        insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last);
1563#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1564    _LIBCPP_INLINE_VISIBILITY
1565    iterator insert(const_iterator __pos, initializer_list<value_type> __il)
1566                    {return insert(__pos, __il.begin(), __il.end());}
1567#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1568
1569    basic_string& erase(size_type __pos = 0, size_type __n = npos);
1570    _LIBCPP_INLINE_VISIBILITY
1571    iterator      erase(const_iterator __pos);
1572    _LIBCPP_INLINE_VISIBILITY
1573    iterator      erase(const_iterator __first, const_iterator __last);
1574
1575    _LIBCPP_INLINE_VISIBILITY
1576    basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str);
1577    basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos);
1578    basic_string& replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2);
1579    basic_string& replace(size_type __pos, size_type __n1, const value_type* __s);
1580    basic_string& replace(size_type __pos, size_type __n1, size_type __n2, value_type __c);
1581    _LIBCPP_INLINE_VISIBILITY
1582    basic_string& replace(const_iterator __i1, const_iterator __i2, const basic_string& __str);
1583    _LIBCPP_INLINE_VISIBILITY
1584    basic_string& replace(const_iterator __i1, const_iterator __i2, const value_type* __s, size_type __n);
1585    _LIBCPP_INLINE_VISIBILITY
1586    basic_string& replace(const_iterator __i1, const_iterator __i2, const value_type* __s);
1587    _LIBCPP_INLINE_VISIBILITY
1588    basic_string& replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c);
1589    template<class _InputIterator>
1590        typename enable_if
1591        <
1592            __is_input_iterator<_InputIterator>::value,
1593            basic_string&
1594        >::type
1595        replace(const_iterator __i1, const_iterator __i2, _InputIterator __j1, _InputIterator __j2);
1596#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1597    _LIBCPP_INLINE_VISIBILITY
1598    basic_string& replace(const_iterator __i1, const_iterator __i2, initializer_list<value_type> __il)
1599        {return replace(__i1, __i2, __il.begin(), __il.end());}
1600#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1601
1602    size_type copy(value_type* __s, size_type __n, size_type __pos = 0) const;
1603    _LIBCPP_INLINE_VISIBILITY
1604    basic_string substr(size_type __pos = 0, size_type __n = npos) const;
1605
1606    _LIBCPP_INLINE_VISIBILITY
1607    void swap(basic_string& __str)
1608#if _LIBCPP_STD_VER >= 14
1609        _NOEXCEPT;
1610#else
1611        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
1612                    __is_nothrow_swappable<allocator_type>::value);
1613#endif
1614
1615    _LIBCPP_INLINE_VISIBILITY
1616    const value_type* c_str() const _NOEXCEPT {return data();}
1617    _LIBCPP_INLINE_VISIBILITY
1618    const value_type* data() const _NOEXCEPT  {return _VSTD::__to_raw_pointer(__get_pointer());}
1619
1620    _LIBCPP_INLINE_VISIBILITY
1621    allocator_type get_allocator() const _NOEXCEPT {return __alloc();}
1622
1623    _LIBCPP_INLINE_VISIBILITY
1624    size_type find(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
1625    size_type find(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1626    _LIBCPP_INLINE_VISIBILITY
1627    size_type find(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
1628    size_type find(value_type __c, size_type __pos = 0) const _NOEXCEPT;
1629
1630    _LIBCPP_INLINE_VISIBILITY
1631    size_type rfind(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
1632    size_type rfind(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1633    _LIBCPP_INLINE_VISIBILITY
1634    size_type rfind(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
1635    size_type rfind(value_type __c, size_type __pos = npos) const _NOEXCEPT;
1636
1637    _LIBCPP_INLINE_VISIBILITY
1638    size_type find_first_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
1639    size_type find_first_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1640    _LIBCPP_INLINE_VISIBILITY
1641    size_type find_first_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
1642    _LIBCPP_INLINE_VISIBILITY
1643    size_type find_first_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
1644
1645    _LIBCPP_INLINE_VISIBILITY
1646    size_type find_last_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
1647    size_type find_last_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1648    _LIBCPP_INLINE_VISIBILITY
1649    size_type find_last_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
1650    _LIBCPP_INLINE_VISIBILITY
1651    size_type find_last_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
1652
1653    _LIBCPP_INLINE_VISIBILITY
1654    size_type find_first_not_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
1655    size_type find_first_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1656    _LIBCPP_INLINE_VISIBILITY
1657    size_type find_first_not_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
1658    _LIBCPP_INLINE_VISIBILITY
1659    size_type find_first_not_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
1660
1661    _LIBCPP_INLINE_VISIBILITY
1662    size_type find_last_not_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
1663    size_type find_last_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1664    _LIBCPP_INLINE_VISIBILITY
1665    size_type find_last_not_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
1666    _LIBCPP_INLINE_VISIBILITY
1667    size_type find_last_not_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
1668
1669    _LIBCPP_INLINE_VISIBILITY
1670    int compare(const basic_string& __str) const _NOEXCEPT;
1671    _LIBCPP_INLINE_VISIBILITY
1672    int compare(size_type __pos1, size_type __n1, const basic_string& __str) const;
1673    int compare(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos) const;
1674    int compare(const value_type* __s) const _NOEXCEPT;
1675    int compare(size_type __pos1, size_type __n1, const value_type* __s) const;
1676    int compare(size_type __pos1, size_type __n1, const value_type* __s, size_type __n2) const;
1677
1678    _LIBCPP_INLINE_VISIBILITY bool __invariants() const;
1679
1680    _LIBCPP_INLINE_VISIBILITY
1681    bool __is_long() const _NOEXCEPT
1682        {return bool(__r_.first().__s.__size_ & __short_mask);}
1683
1684#if _LIBCPP_DEBUG_LEVEL >= 2
1685
1686    bool __dereferenceable(const const_iterator* __i) const;
1687    bool __decrementable(const const_iterator* __i) const;
1688    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
1689    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
1690
1691#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1692
1693private:
1694    _LIBCPP_INLINE_VISIBILITY
1695    allocator_type& __alloc() _NOEXCEPT
1696        {return __r_.second();}
1697    _LIBCPP_INLINE_VISIBILITY
1698    const allocator_type& __alloc() const _NOEXCEPT
1699        {return __r_.second();}
1700
1701#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1702
1703    _LIBCPP_INLINE_VISIBILITY
1704    void __set_short_size(size_type __s) _NOEXCEPT
1705#   if _LIBCPP_BIG_ENDIAN
1706        {__r_.first().__s.__size_ = (unsigned char)(__s << 1);}
1707#   else
1708        {__r_.first().__s.__size_ = (unsigned char)(__s);}
1709#   endif
1710
1711    _LIBCPP_INLINE_VISIBILITY
1712    size_type __get_short_size() const _NOEXCEPT
1713#   if _LIBCPP_BIG_ENDIAN
1714        {return __r_.first().__s.__size_ >> 1;}
1715#   else
1716        {return __r_.first().__s.__size_;}
1717#   endif
1718
1719#else  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1720
1721    _LIBCPP_INLINE_VISIBILITY
1722    void __set_short_size(size_type __s) _NOEXCEPT
1723#   if _LIBCPP_BIG_ENDIAN
1724        {__r_.first().__s.__size_ = (unsigned char)(__s);}
1725#   else
1726        {__r_.first().__s.__size_ = (unsigned char)(__s << 1);}
1727#   endif
1728
1729    _LIBCPP_INLINE_VISIBILITY
1730    size_type __get_short_size() const _NOEXCEPT
1731#   if _LIBCPP_BIG_ENDIAN
1732        {return __r_.first().__s.__size_;}
1733#   else
1734        {return __r_.first().__s.__size_ >> 1;}
1735#   endif
1736
1737#endif  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1738
1739    _LIBCPP_INLINE_VISIBILITY
1740    void __set_long_size(size_type __s) _NOEXCEPT
1741        {__r_.first().__l.__size_ = __s;}
1742    _LIBCPP_INLINE_VISIBILITY
1743    size_type __get_long_size() const _NOEXCEPT
1744        {return __r_.first().__l.__size_;}
1745    _LIBCPP_INLINE_VISIBILITY
1746    void __set_size(size_type __s) _NOEXCEPT
1747        {if (__is_long()) __set_long_size(__s); else __set_short_size(__s);}
1748
1749    _LIBCPP_INLINE_VISIBILITY
1750    void __set_long_cap(size_type __s) _NOEXCEPT
1751        {__r_.first().__l.__cap_  = __long_mask | __s;}
1752    _LIBCPP_INLINE_VISIBILITY
1753    size_type __get_long_cap() const _NOEXCEPT
1754        {return __r_.first().__l.__cap_ & size_type(~__long_mask);}
1755
1756    _LIBCPP_INLINE_VISIBILITY
1757    void __set_long_pointer(pointer __p) _NOEXCEPT
1758        {__r_.first().__l.__data_ = __p;}
1759    _LIBCPP_INLINE_VISIBILITY
1760    pointer __get_long_pointer() _NOEXCEPT
1761        {return __r_.first().__l.__data_;}
1762    _LIBCPP_INLINE_VISIBILITY
1763    const_pointer __get_long_pointer() const _NOEXCEPT
1764        {return __r_.first().__l.__data_;}
1765    _LIBCPP_INLINE_VISIBILITY
1766    pointer __get_short_pointer() _NOEXCEPT
1767        {return pointer_traits<pointer>::pointer_to(__r_.first().__s.__data_[0]);}
1768    _LIBCPP_INLINE_VISIBILITY
1769    const_pointer __get_short_pointer() const _NOEXCEPT
1770        {return pointer_traits<const_pointer>::pointer_to(__r_.first().__s.__data_[0]);}
1771    _LIBCPP_INLINE_VISIBILITY
1772    pointer __get_pointer() _NOEXCEPT
1773        {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
1774    _LIBCPP_INLINE_VISIBILITY
1775    const_pointer __get_pointer() const _NOEXCEPT
1776        {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
1777
1778    _LIBCPP_INLINE_VISIBILITY
1779    void __zero() _NOEXCEPT
1780        {
1781            size_type (&__a)[__n_words] = __r_.first().__r.__words;
1782            for (unsigned __i = 0; __i < __n_words; ++__i)
1783                __a[__i] = 0;
1784        }
1785
1786    template <size_type __a> static
1787        _LIBCPP_INLINE_VISIBILITY
1788        size_type __align_it(size_type __s) _NOEXCEPT
1789            {return (__s + (__a-1)) & ~(__a-1);}
1790    enum {__alignment = 16};
1791    static _LIBCPP_INLINE_VISIBILITY
1792    size_type __recommend(size_type __s) _NOEXCEPT
1793        {return (__s < __min_cap ? static_cast<size_type>(__min_cap) :
1794                 __align_it<sizeof(value_type) < __alignment ?
1795                            __alignment/sizeof(value_type) : 1 > (__s+1)) - 1;}
1796
1797    void __init(const value_type* __s, size_type __sz, size_type __reserve);
1798    void __init(const value_type* __s, size_type __sz);
1799    void __init(size_type __n, value_type __c);
1800
1801    template <class _InputIterator>
1802    typename enable_if
1803    <
1804         __is_input_iterator  <_InputIterator>::value &&
1805        !__is_forward_iterator<_InputIterator>::value,
1806        void
1807    >::type
1808    __init(_InputIterator __first, _InputIterator __last);
1809
1810    template <class _ForwardIterator>
1811    typename enable_if
1812    <
1813        __is_forward_iterator<_ForwardIterator>::value,
1814        void
1815    >::type
1816    __init(_ForwardIterator __first, _ForwardIterator __last);
1817
1818    void __grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
1819                   size_type __n_copy,  size_type __n_del,     size_type __n_add = 0);
1820    void __grow_by_and_replace(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
1821                               size_type __n_copy,  size_type __n_del,
1822                               size_type __n_add, const value_type* __p_new_stuff);
1823
1824    _LIBCPP_INLINE_VISIBILITY
1825    void __erase_to_end(size_type __pos);
1826
1827    _LIBCPP_INLINE_VISIBILITY
1828    void __copy_assign_alloc(const basic_string& __str)
1829        {__copy_assign_alloc(__str, integral_constant<bool,
1830                      __alloc_traits::propagate_on_container_copy_assignment::value>());}
1831
1832    _LIBCPP_INLINE_VISIBILITY
1833    void __copy_assign_alloc(const basic_string& __str, true_type)
1834        {
1835            if (__alloc() != __str.__alloc())
1836            {
1837                clear();
1838                shrink_to_fit();
1839            }
1840            __alloc() = __str.__alloc();
1841        }
1842
1843    _LIBCPP_INLINE_VISIBILITY
1844    void __copy_assign_alloc(const basic_string&, false_type) _NOEXCEPT
1845        {}
1846
1847#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1848    _LIBCPP_INLINE_VISIBILITY
1849    void __move_assign(basic_string& __str, false_type)
1850        _NOEXCEPT_(__alloc_traits::is_always_equal::value);
1851    _LIBCPP_INLINE_VISIBILITY
1852    void __move_assign(basic_string& __str, true_type)
1853#if _LIBCPP_STD_VER > 14
1854        _NOEXCEPT;
1855#else
1856        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
1857#endif
1858#endif
1859
1860    _LIBCPP_INLINE_VISIBILITY
1861    void
1862    __move_assign_alloc(basic_string& __str)
1863        _NOEXCEPT_(
1864            !__alloc_traits::propagate_on_container_move_assignment::value ||
1865            is_nothrow_move_assignable<allocator_type>::value)
1866    {__move_assign_alloc(__str, integral_constant<bool,
1867                      __alloc_traits::propagate_on_container_move_assignment::value>());}
1868
1869    _LIBCPP_INLINE_VISIBILITY
1870    void __move_assign_alloc(basic_string& __c, true_type)
1871        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
1872        {
1873            __alloc() = _VSTD::move(__c.__alloc());
1874        }
1875
1876    _LIBCPP_INLINE_VISIBILITY
1877    void __move_assign_alloc(basic_string&, false_type)
1878        _NOEXCEPT
1879        {}
1880
1881    _LIBCPP_INLINE_VISIBILITY void __invalidate_all_iterators();
1882    _LIBCPP_INLINE_VISIBILITY void __invalidate_iterators_past(size_type);
1883
1884    friend basic_string operator+<>(const basic_string&, const basic_string&);
1885    friend basic_string operator+<>(const value_type*, const basic_string&);
1886    friend basic_string operator+<>(value_type, const basic_string&);
1887    friend basic_string operator+<>(const basic_string&, const value_type*);
1888    friend basic_string operator+<>(const basic_string&, value_type);
1889};
1890
1891template <class _CharT, class _Traits, class _Allocator>
1892inline _LIBCPP_INLINE_VISIBILITY
1893void
1894basic_string<_CharT, _Traits, _Allocator>::__invalidate_all_iterators()
1895{
1896#if _LIBCPP_DEBUG_LEVEL >= 2
1897    __get_db()->__invalidate_all(this);
1898#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1899}
1900
1901template <class _CharT, class _Traits, class _Allocator>
1902inline _LIBCPP_INLINE_VISIBILITY
1903void
1904basic_string<_CharT, _Traits, _Allocator>::__invalidate_iterators_past(size_type
1905#if _LIBCPP_DEBUG_LEVEL >= 2
1906                                                                        __pos
1907#endif
1908                                                                      )
1909{
1910#if _LIBCPP_DEBUG_LEVEL >= 2
1911    __c_node* __c = __get_db()->__find_c_and_lock(this);
1912    if (__c)
1913    {
1914        const_pointer __new_last = __get_pointer() + __pos;
1915        for (__i_node** __p = __c->end_; __p != __c->beg_; )
1916        {
1917            --__p;
1918            const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
1919            if (__i->base() > __new_last)
1920            {
1921                (*__p)->__c_ = nullptr;
1922                if (--__c->end_ != __p)
1923                    memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
1924            }
1925        }
1926        __get_db()->unlock();
1927    }
1928#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1929}
1930
1931template <class _CharT, class _Traits, class _Allocator>
1932inline _LIBCPP_INLINE_VISIBILITY
1933basic_string<_CharT, _Traits, _Allocator>::basic_string()
1934    _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
1935{
1936#if _LIBCPP_DEBUG_LEVEL >= 2
1937    __get_db()->__insert_c(this);
1938#endif
1939    __zero();
1940}
1941
1942template <class _CharT, class _Traits, class _Allocator>
1943inline _LIBCPP_INLINE_VISIBILITY
1944basic_string<_CharT, _Traits, _Allocator>::basic_string(const allocator_type& __a)
1945#if _LIBCPP_STD_VER <= 14
1946        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
1947#else
1948        _NOEXCEPT
1949#endif
1950: __r_(__a)
1951{
1952#if _LIBCPP_DEBUG_LEVEL >= 2
1953    __get_db()->__insert_c(this);
1954#endif
1955    __zero();
1956}
1957
1958template <class _CharT, class _Traits, class _Allocator>
1959void
1960basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz, size_type __reserve)
1961{
1962    if (__reserve > max_size())
1963        this->__throw_length_error();
1964    pointer __p;
1965    if (__reserve < __min_cap)
1966    {
1967        __set_short_size(__sz);
1968        __p = __get_short_pointer();
1969    }
1970    else
1971    {
1972        size_type __cap = __recommend(__reserve);
1973        __p = __alloc_traits::allocate(__alloc(), __cap+1);
1974        __set_long_pointer(__p);
1975        __set_long_cap(__cap+1);
1976        __set_long_size(__sz);
1977    }
1978    traits_type::copy(_VSTD::__to_raw_pointer(__p), __s, __sz);
1979    traits_type::assign(__p[__sz], value_type());
1980}
1981
1982template <class _CharT, class _Traits, class _Allocator>
1983void
1984basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz)
1985{
1986    if (__sz > max_size())
1987        this->__throw_length_error();
1988    pointer __p;
1989    if (__sz < __min_cap)
1990    {
1991        __set_short_size(__sz);
1992        __p = __get_short_pointer();
1993    }
1994    else
1995    {
1996        size_type __cap = __recommend(__sz);
1997        __p = __alloc_traits::allocate(__alloc(), __cap+1);
1998        __set_long_pointer(__p);
1999        __set_long_cap(__cap+1);
2000        __set_long_size(__sz);
2001    }
2002    traits_type::copy(_VSTD::__to_raw_pointer(__p), __s, __sz);
2003    traits_type::assign(__p[__sz], value_type());
2004}
2005
2006template <class _CharT, class _Traits, class _Allocator>
2007inline _LIBCPP_INLINE_VISIBILITY
2008basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s)
2009{
2010    _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*) detected nullptr");
2011    __init(__s, traits_type::length(__s));
2012#if _LIBCPP_DEBUG_LEVEL >= 2
2013    __get_db()->__insert_c(this);
2014#endif
2015}
2016
2017template <class _CharT, class _Traits, class _Allocator>
2018inline _LIBCPP_INLINE_VISIBILITY
2019basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s, const allocator_type& __a)
2020    : __r_(__a)
2021{
2022    _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*, allocator) detected nullptr");
2023    __init(__s, traits_type::length(__s));
2024#if _LIBCPP_DEBUG_LEVEL >= 2
2025    __get_db()->__insert_c(this);
2026#endif
2027}
2028
2029template <class _CharT, class _Traits, class _Allocator>
2030inline _LIBCPP_INLINE_VISIBILITY
2031basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s, size_type __n)
2032{
2033    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n) detected nullptr");
2034    __init(__s, __n);
2035#if _LIBCPP_DEBUG_LEVEL >= 2
2036    __get_db()->__insert_c(this);
2037#endif
2038}
2039
2040template <class _CharT, class _Traits, class _Allocator>
2041inline _LIBCPP_INLINE_VISIBILITY
2042basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s, size_type __n, const allocator_type& __a)
2043    : __r_(__a)
2044{
2045    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n, allocator) detected nullptr");
2046    __init(__s, __n);
2047#if _LIBCPP_DEBUG_LEVEL >= 2
2048    __get_db()->__insert_c(this);
2049#endif
2050}
2051
2052template <class _CharT, class _Traits, class _Allocator>
2053basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str)
2054    : __r_(__alloc_traits::select_on_container_copy_construction(__str.__alloc()))
2055{
2056    if (!__str.__is_long())
2057        __r_.first().__r = __str.__r_.first().__r;
2058    else
2059        __init(_VSTD::__to_raw_pointer(__str.__get_long_pointer()), __str.__get_long_size());
2060#if _LIBCPP_DEBUG_LEVEL >= 2
2061    __get_db()->__insert_c(this);
2062#endif
2063}
2064
2065template <class _CharT, class _Traits, class _Allocator>
2066basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str, const allocator_type& __a)
2067    : __r_(__a)
2068{
2069    if (!__str.__is_long())
2070        __r_.first().__r = __str.__r_.first().__r;
2071    else
2072        __init(_VSTD::__to_raw_pointer(__str.__get_long_pointer()), __str.__get_long_size());
2073#if _LIBCPP_DEBUG_LEVEL >= 2
2074    __get_db()->__insert_c(this);
2075#endif
2076}
2077
2078#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2079
2080template <class _CharT, class _Traits, class _Allocator>
2081inline _LIBCPP_INLINE_VISIBILITY
2082basic_string<_CharT, _Traits, _Allocator>::basic_string(basic_string&& __str)
2083#if _LIBCPP_STD_VER <= 14
2084        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
2085#else
2086        _NOEXCEPT
2087#endif
2088    : __r_(_VSTD::move(__str.__r_))
2089{
2090    __str.__zero();
2091#if _LIBCPP_DEBUG_LEVEL >= 2
2092    __get_db()->__insert_c(this);
2093    if (__is_long())
2094        __get_db()->swap(this, &__str);
2095#endif
2096}
2097
2098template <class _CharT, class _Traits, class _Allocator>
2099inline _LIBCPP_INLINE_VISIBILITY
2100basic_string<_CharT, _Traits, _Allocator>::basic_string(basic_string&& __str, const allocator_type& __a)
2101    : __r_(__a)
2102{
2103    if (__str.__is_long() && __a != __str.__alloc()) // copy, not move
2104        __init(_VSTD::__to_raw_pointer(__str.__get_long_pointer()), __str.__get_long_size());
2105    else
2106    {
2107        __r_.first().__r = __str.__r_.first().__r;
2108        __str.__zero();
2109    }
2110#if _LIBCPP_DEBUG_LEVEL >= 2
2111    __get_db()->__insert_c(this);
2112    if (__is_long())
2113        __get_db()->swap(this, &__str);
2114#endif
2115}
2116
2117#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
2118
2119template <class _CharT, class _Traits, class _Allocator>
2120void
2121basic_string<_CharT, _Traits, _Allocator>::__init(size_type __n, value_type __c)
2122{
2123    if (__n > max_size())
2124        this->__throw_length_error();
2125    pointer __p;
2126    if (__n < __min_cap)
2127    {
2128        __set_short_size(__n);
2129        __p = __get_short_pointer();
2130    }
2131    else
2132    {
2133        size_type __cap = __recommend(__n);
2134        __p = __alloc_traits::allocate(__alloc(), __cap+1);
2135        __set_long_pointer(__p);
2136        __set_long_cap(__cap+1);
2137        __set_long_size(__n);
2138    }
2139    traits_type::assign(_VSTD::__to_raw_pointer(__p), __n, __c);
2140    traits_type::assign(__p[__n], value_type());
2141}
2142
2143template <class _CharT, class _Traits, class _Allocator>
2144inline _LIBCPP_INLINE_VISIBILITY
2145basic_string<_CharT, _Traits, _Allocator>::basic_string(size_type __n, value_type __c)
2146{
2147    __init(__n, __c);
2148#if _LIBCPP_DEBUG_LEVEL >= 2
2149    __get_db()->__insert_c(this);
2150#endif
2151}
2152
2153template <class _CharT, class _Traits, class _Allocator>
2154inline _LIBCPP_INLINE_VISIBILITY
2155basic_string<_CharT, _Traits, _Allocator>::basic_string(size_type __n, value_type __c, const allocator_type& __a)
2156    : __r_(__a)
2157{
2158    __init(__n, __c);
2159#if _LIBCPP_DEBUG_LEVEL >= 2
2160    __get_db()->__insert_c(this);
2161#endif
2162}
2163
2164template <class _CharT, class _Traits, class _Allocator>
2165basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str, size_type __pos, size_type __n,
2166                                                        const allocator_type& __a)
2167    : __r_(__a)
2168{
2169    size_type __str_sz = __str.size();
2170    if (__pos > __str_sz)
2171        this->__throw_out_of_range();
2172    __init(__str.data() + __pos, _VSTD::min(__n, __str_sz - __pos));
2173#if _LIBCPP_DEBUG_LEVEL >= 2
2174    __get_db()->__insert_c(this);
2175#endif
2176}
2177
2178template <class _CharT, class _Traits, class _Allocator>
2179template <class _InputIterator>
2180typename enable_if
2181<
2182     __is_input_iterator  <_InputIterator>::value &&
2183    !__is_forward_iterator<_InputIterator>::value,
2184    void
2185>::type
2186basic_string<_CharT, _Traits, _Allocator>::__init(_InputIterator __first, _InputIterator __last)
2187{
2188    __zero();
2189#ifndef _LIBCPP_NO_EXCEPTIONS
2190    try
2191    {
2192#endif  // _LIBCPP_NO_EXCEPTIONS
2193    for (; __first != __last; ++__first)
2194        push_back(*__first);
2195#ifndef _LIBCPP_NO_EXCEPTIONS
2196    }
2197    catch (...)
2198    {
2199        if (__is_long())
2200            __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
2201        throw;
2202    }
2203#endif  // _LIBCPP_NO_EXCEPTIONS
2204}
2205
2206template <class _CharT, class _Traits, class _Allocator>
2207template <class _ForwardIterator>
2208typename enable_if
2209<
2210    __is_forward_iterator<_ForwardIterator>::value,
2211    void
2212>::type
2213basic_string<_CharT, _Traits, _Allocator>::__init(_ForwardIterator __first, _ForwardIterator __last)
2214{
2215    size_type __sz = static_cast<size_type>(_VSTD::distance(__first, __last));
2216    if (__sz > max_size())
2217        this->__throw_length_error();
2218    pointer __p;
2219    if (__sz < __min_cap)
2220    {
2221        __set_short_size(__sz);
2222        __p = __get_short_pointer();
2223    }
2224    else
2225    {
2226        size_type __cap = __recommend(__sz);
2227        __p = __alloc_traits::allocate(__alloc(), __cap+1);
2228        __set_long_pointer(__p);
2229        __set_long_cap(__cap+1);
2230        __set_long_size(__sz);
2231    }
2232    for (; __first != __last; ++__first, (void) ++__p)
2233        traits_type::assign(*__p, *__first);
2234    traits_type::assign(*__p, value_type());
2235}
2236
2237template <class _CharT, class _Traits, class _Allocator>
2238template<class _InputIterator>
2239inline _LIBCPP_INLINE_VISIBILITY
2240basic_string<_CharT, _Traits, _Allocator>::basic_string(_InputIterator __first, _InputIterator __last)
2241{
2242    __init(__first, __last);
2243#if _LIBCPP_DEBUG_LEVEL >= 2
2244    __get_db()->__insert_c(this);
2245#endif
2246}
2247
2248template <class _CharT, class _Traits, class _Allocator>
2249template<class _InputIterator>
2250inline _LIBCPP_INLINE_VISIBILITY
2251basic_string<_CharT, _Traits, _Allocator>::basic_string(_InputIterator __first, _InputIterator __last,
2252                                                        const allocator_type& __a)
2253    : __r_(__a)
2254{
2255    __init(__first, __last);
2256#if _LIBCPP_DEBUG_LEVEL >= 2
2257    __get_db()->__insert_c(this);
2258#endif
2259}
2260
2261#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2262
2263template <class _CharT, class _Traits, class _Allocator>
2264inline _LIBCPP_INLINE_VISIBILITY
2265basic_string<_CharT, _Traits, _Allocator>::basic_string(initializer_list<value_type> __il)
2266{
2267    __init(__il.begin(), __il.end());
2268#if _LIBCPP_DEBUG_LEVEL >= 2
2269    __get_db()->__insert_c(this);
2270#endif
2271}
2272
2273template <class _CharT, class _Traits, class _Allocator>
2274inline _LIBCPP_INLINE_VISIBILITY
2275basic_string<_CharT, _Traits, _Allocator>::basic_string(initializer_list<value_type> __il, const allocator_type& __a)
2276    : __r_(__a)
2277{
2278    __init(__il.begin(), __il.end());
2279#if _LIBCPP_DEBUG_LEVEL >= 2
2280    __get_db()->__insert_c(this);
2281#endif
2282}
2283
2284#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2285
2286template <class _CharT, class _Traits, class _Allocator>
2287basic_string<_CharT, _Traits, _Allocator>::~basic_string()
2288{
2289#if _LIBCPP_DEBUG_LEVEL >= 2
2290    __get_db()->__erase_c(this);
2291#endif
2292    if (__is_long())
2293        __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
2294}
2295
2296template <class _CharT, class _Traits, class _Allocator>
2297void
2298basic_string<_CharT, _Traits, _Allocator>::__grow_by_and_replace
2299    (size_type __old_cap, size_type __delta_cap, size_type __old_sz,
2300     size_type __n_copy,  size_type __n_del,     size_type __n_add, const value_type* __p_new_stuff)
2301{
2302    size_type __ms = max_size();
2303    if (__delta_cap > __ms - __old_cap - 1)
2304        this->__throw_length_error();
2305    pointer __old_p = __get_pointer();
2306    size_type __cap = __old_cap < __ms / 2 - __alignment ?
2307                          __recommend(_VSTD::max(__old_cap + __delta_cap, 2 * __old_cap)) :
2308                          __ms - 1;
2309    pointer __p = __alloc_traits::allocate(__alloc(), __cap+1);
2310    __invalidate_all_iterators();
2311    if (__n_copy != 0)
2312        traits_type::copy(_VSTD::__to_raw_pointer(__p),
2313                          _VSTD::__to_raw_pointer(__old_p), __n_copy);
2314    if (__n_add != 0)
2315        traits_type::copy(_VSTD::__to_raw_pointer(__p) + __n_copy, __p_new_stuff, __n_add);
2316    size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
2317    if (__sec_cp_sz != 0)
2318        traits_type::copy(_VSTD::__to_raw_pointer(__p) + __n_copy + __n_add,
2319                          _VSTD::__to_raw_pointer(__old_p) + __n_copy + __n_del, __sec_cp_sz);
2320    if (__old_cap+1 != __min_cap)
2321        __alloc_traits::deallocate(__alloc(), __old_p, __old_cap+1);
2322    __set_long_pointer(__p);
2323    __set_long_cap(__cap+1);
2324    __old_sz = __n_copy + __n_add + __sec_cp_sz;
2325    __set_long_size(__old_sz);
2326    traits_type::assign(__p[__old_sz], value_type());
2327}
2328
2329template <class _CharT, class _Traits, class _Allocator>
2330void
2331basic_string<_CharT, _Traits, _Allocator>::__grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
2332                                                     size_type __n_copy,  size_type __n_del,     size_type __n_add)
2333{
2334    size_type __ms = max_size();
2335    if (__delta_cap > __ms - __old_cap)
2336        this->__throw_length_error();
2337    pointer __old_p = __get_pointer();
2338    size_type __cap = __old_cap < __ms / 2 - __alignment ?
2339                          __recommend(_VSTD::max(__old_cap + __delta_cap, 2 * __old_cap)) :
2340                          __ms - 1;
2341    pointer __p = __alloc_traits::allocate(__alloc(), __cap+1);
2342    __invalidate_all_iterators();
2343    if (__n_copy != 0)
2344        traits_type::copy(_VSTD::__to_raw_pointer(__p),
2345                          _VSTD::__to_raw_pointer(__old_p), __n_copy);
2346    size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
2347    if (__sec_cp_sz != 0)
2348        traits_type::copy(_VSTD::__to_raw_pointer(__p) + __n_copy + __n_add,
2349                          _VSTD::__to_raw_pointer(__old_p) + __n_copy + __n_del,
2350                          __sec_cp_sz);
2351    if (__old_cap+1 != __min_cap)
2352        __alloc_traits::deallocate(__alloc(), __old_p, __old_cap+1);
2353    __set_long_pointer(__p);
2354    __set_long_cap(__cap+1);
2355}
2356
2357// assign
2358
2359template <class _CharT, class _Traits, class _Allocator>
2360basic_string<_CharT, _Traits, _Allocator>&
2361basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s, size_type __n)
2362{
2363    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::assign received nullptr");
2364    size_type __cap = capacity();
2365    if (__cap >= __n)
2366    {
2367        value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2368        traits_type::move(__p, __s, __n);
2369        traits_type::assign(__p[__n], value_type());
2370        __set_size(__n);
2371        __invalidate_iterators_past(__n);
2372    }
2373    else
2374    {
2375        size_type __sz = size();
2376        __grow_by_and_replace(__cap, __n - __cap, __sz, 0, __sz, __n, __s);
2377    }
2378    return *this;
2379}
2380
2381template <class _CharT, class _Traits, class _Allocator>
2382basic_string<_CharT, _Traits, _Allocator>&
2383basic_string<_CharT, _Traits, _Allocator>::assign(size_type __n, value_type __c)
2384{
2385    size_type __cap = capacity();
2386    if (__cap < __n)
2387    {
2388        size_type __sz = size();
2389        __grow_by(__cap, __n - __cap, __sz, 0, __sz);
2390    }
2391    else
2392        __invalidate_iterators_past(__n);
2393    value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2394    traits_type::assign(__p, __n, __c);
2395    traits_type::assign(__p[__n], value_type());
2396    __set_size(__n);
2397    return *this;
2398}
2399
2400template <class _CharT, class _Traits, class _Allocator>
2401basic_string<_CharT, _Traits, _Allocator>&
2402basic_string<_CharT, _Traits, _Allocator>::operator=(value_type __c)
2403{
2404    pointer __p;
2405    if (__is_long())
2406    {
2407        __p = __get_long_pointer();
2408        __set_long_size(1);
2409    }
2410    else
2411    {
2412        __p = __get_short_pointer();
2413        __set_short_size(1);
2414    }
2415    traits_type::assign(*__p, __c);
2416    traits_type::assign(*++__p, value_type());
2417    __invalidate_iterators_past(1);
2418    return *this;
2419}
2420
2421template <class _CharT, class _Traits, class _Allocator>
2422basic_string<_CharT, _Traits, _Allocator>&
2423basic_string<_CharT, _Traits, _Allocator>::operator=(const basic_string& __str)
2424{
2425    if (this != &__str)
2426    {
2427        __copy_assign_alloc(__str);
2428        assign(__str);
2429    }
2430    return *this;
2431}
2432
2433#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2434
2435template <class _CharT, class _Traits, class _Allocator>
2436inline _LIBCPP_INLINE_VISIBILITY
2437void
2438basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, false_type)
2439    _NOEXCEPT_(__alloc_traits::is_always_equal::value)
2440{
2441    if (__alloc() != __str.__alloc())
2442        assign(__str);
2443    else
2444        __move_assign(__str, true_type());
2445}
2446
2447template <class _CharT, class _Traits, class _Allocator>
2448inline _LIBCPP_INLINE_VISIBILITY
2449void
2450basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, true_type)
2451#if _LIBCPP_STD_VER > 14
2452    _NOEXCEPT
2453#else
2454    _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
2455#endif
2456{
2457    clear();
2458    shrink_to_fit();
2459    __r_.first() = __str.__r_.first();
2460    __move_assign_alloc(__str);
2461    __str.__zero();
2462}
2463
2464template <class _CharT, class _Traits, class _Allocator>
2465inline _LIBCPP_INLINE_VISIBILITY
2466basic_string<_CharT, _Traits, _Allocator>&
2467basic_string<_CharT, _Traits, _Allocator>::operator=(basic_string&& __str)
2468    _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
2469{
2470    __move_assign(__str, integral_constant<bool,
2471          __alloc_traits::propagate_on_container_move_assignment::value>());
2472    return *this;
2473}
2474
2475#endif
2476
2477template <class _CharT, class _Traits, class _Allocator>
2478template<class _InputIterator>
2479typename enable_if
2480<
2481     __is_input_iterator  <_InputIterator>::value &&
2482    !__is_forward_iterator<_InputIterator>::value,
2483    basic_string<_CharT, _Traits, _Allocator>&
2484>::type
2485basic_string<_CharT, _Traits, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
2486{
2487    clear();
2488    for (; __first != __last; ++__first)
2489        push_back(*__first);
2490    return *this;
2491}
2492
2493template <class _CharT, class _Traits, class _Allocator>
2494template<class _ForwardIterator>
2495typename enable_if
2496<
2497    __is_forward_iterator<_ForwardIterator>::value,
2498    basic_string<_CharT, _Traits, _Allocator>&
2499>::type
2500basic_string<_CharT, _Traits, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
2501{
2502    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
2503    size_type __cap = capacity();
2504    if (__cap < __n)
2505    {
2506        size_type __sz = size();
2507        __grow_by(__cap, __n - __cap, __sz, 0, __sz);
2508    }
2509    else
2510        __invalidate_iterators_past(__n);
2511    pointer __p = __get_pointer();
2512    for (; __first != __last; ++__first, ++__p)
2513        traits_type::assign(*__p, *__first);
2514    traits_type::assign(*__p, value_type());
2515    __set_size(__n);
2516    return *this;
2517}
2518
2519template <class _CharT, class _Traits, class _Allocator>
2520inline _LIBCPP_INLINE_VISIBILITY
2521basic_string<_CharT, _Traits, _Allocator>&
2522basic_string<_CharT, _Traits, _Allocator>::assign(const basic_string& __str)
2523{
2524    return assign(__str.data(), __str.size());
2525}
2526
2527template <class _CharT, class _Traits, class _Allocator>
2528basic_string<_CharT, _Traits, _Allocator>&
2529basic_string<_CharT, _Traits, _Allocator>::assign(const basic_string& __str, size_type __pos, size_type __n)
2530{
2531    size_type __sz = __str.size();
2532    if (__pos > __sz)
2533        this->__throw_out_of_range();
2534    return assign(__str.data() + __pos, _VSTD::min(__n, __sz - __pos));
2535}
2536
2537template <class _CharT, class _Traits, class _Allocator>
2538basic_string<_CharT, _Traits, _Allocator>&
2539basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s)
2540{
2541    _LIBCPP_ASSERT(__s != nullptr, "string::assign received nullptr");
2542    return assign(__s, traits_type::length(__s));
2543}
2544
2545// append
2546
2547template <class _CharT, class _Traits, class _Allocator>
2548basic_string<_CharT, _Traits, _Allocator>&
2549basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s, size_type __n)
2550{
2551    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::append received nullptr");
2552    size_type __cap = capacity();
2553    size_type __sz = size();
2554    if (__cap - __sz >= __n)
2555    {
2556        if (__n)
2557        {
2558            value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2559            traits_type::copy(__p + __sz, __s, __n);
2560            __sz += __n;
2561            __set_size(__sz);
2562            traits_type::assign(__p[__sz], value_type());
2563        }
2564    }
2565    else
2566        __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __sz, 0, __n, __s);
2567    return *this;
2568}
2569
2570template <class _CharT, class _Traits, class _Allocator>
2571basic_string<_CharT, _Traits, _Allocator>&
2572basic_string<_CharT, _Traits, _Allocator>::append(size_type __n, value_type __c)
2573{
2574    if (__n)
2575    {
2576        size_type __cap = capacity();
2577        size_type __sz = size();
2578        if (__cap - __sz < __n)
2579            __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
2580        pointer __p = __get_pointer();
2581        traits_type::assign(_VSTD::__to_raw_pointer(__p) + __sz, __n, __c);
2582        __sz += __n;
2583        __set_size(__sz);
2584        traits_type::assign(__p[__sz], value_type());
2585    }
2586    return *this;
2587}
2588
2589template <class _CharT, class _Traits, class _Allocator>
2590void
2591basic_string<_CharT, _Traits, _Allocator>::push_back(value_type __c)
2592{
2593    bool __is_short = !__is_long();
2594    size_type __cap;
2595    size_type __sz;
2596    if (__is_short)
2597    {
2598        __cap = __min_cap - 1;
2599        __sz = __get_short_size();
2600    }
2601    else
2602    {
2603        __cap = __get_long_cap() - 1;
2604        __sz = __get_long_size();
2605    }
2606    if (__sz == __cap)
2607    {
2608        __grow_by(__cap, 1, __sz, __sz, 0);
2609        __is_short = !__is_long();
2610    }
2611    pointer __p;
2612    if (__is_short)
2613    {
2614        __p = __get_short_pointer() + __sz;
2615        __set_short_size(__sz+1);
2616    }
2617    else
2618    {
2619        __p = __get_long_pointer() + __sz;
2620        __set_long_size(__sz+1);
2621    }
2622    traits_type::assign(*__p, __c);
2623    traits_type::assign(*++__p, value_type());
2624}
2625
2626template <class _CharT, class _Traits, class _Allocator>
2627template<class _InputIterator>
2628typename enable_if
2629<
2630     __is_input_iterator  <_InputIterator>::value &&
2631    !__is_forward_iterator<_InputIterator>::value,
2632    basic_string<_CharT, _Traits, _Allocator>&
2633>::type
2634basic_string<_CharT, _Traits, _Allocator>::append(_InputIterator __first, _InputIterator __last)
2635{
2636    for (; __first != __last; ++__first)
2637        push_back(*__first);
2638    return *this;
2639}
2640
2641template <class _CharT, class _Traits, class _Allocator>
2642template<class _ForwardIterator>
2643typename enable_if
2644<
2645    __is_forward_iterator<_ForwardIterator>::value,
2646    basic_string<_CharT, _Traits, _Allocator>&
2647>::type
2648basic_string<_CharT, _Traits, _Allocator>::append(_ForwardIterator __first, _ForwardIterator __last)
2649{
2650    size_type __sz = size();
2651    size_type __cap = capacity();
2652    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
2653    if (__n)
2654    {
2655        if (__cap - __sz < __n)
2656            __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
2657        pointer __p = __get_pointer() + __sz;
2658        for (; __first != __last; ++__p, ++__first)
2659            traits_type::assign(*__p, *__first);
2660        traits_type::assign(*__p, value_type());
2661        __set_size(__sz + __n);
2662    }
2663    return *this;
2664}
2665
2666template <class _CharT, class _Traits, class _Allocator>
2667inline _LIBCPP_INLINE_VISIBILITY
2668basic_string<_CharT, _Traits, _Allocator>&
2669basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str)
2670{
2671    return append(__str.data(), __str.size());
2672}
2673
2674template <class _CharT, class _Traits, class _Allocator>
2675basic_string<_CharT, _Traits, _Allocator>&
2676basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str, size_type __pos, size_type __n)
2677{
2678    size_type __sz = __str.size();
2679    if (__pos > __sz)
2680        this->__throw_out_of_range();
2681    return append(__str.data() + __pos, _VSTD::min(__n, __sz - __pos));
2682}
2683
2684template <class _CharT, class _Traits, class _Allocator>
2685basic_string<_CharT, _Traits, _Allocator>&
2686basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s)
2687{
2688    _LIBCPP_ASSERT(__s != nullptr, "string::append received nullptr");
2689    return append(__s, traits_type::length(__s));
2690}
2691
2692// insert
2693
2694template <class _CharT, class _Traits, class _Allocator>
2695basic_string<_CharT, _Traits, _Allocator>&
2696basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s, size_type __n)
2697{
2698    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::insert received nullptr");
2699    size_type __sz = size();
2700    if (__pos > __sz)
2701        this->__throw_out_of_range();
2702    size_type __cap = capacity();
2703    if (__cap - __sz >= __n)
2704    {
2705        if (__n)
2706        {
2707            value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2708            size_type __n_move = __sz - __pos;
2709            if (__n_move != 0)
2710            {
2711                if (__p + __pos <= __s && __s < __p + __sz)
2712                    __s += __n;
2713                traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
2714            }
2715            traits_type::move(__p + __pos, __s, __n);
2716            __sz += __n;
2717            __set_size(__sz);
2718            traits_type::assign(__p[__sz], value_type());
2719        }
2720    }
2721    else
2722        __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __pos, 0, __n, __s);
2723    return *this;
2724}
2725
2726template <class _CharT, class _Traits, class _Allocator>
2727basic_string<_CharT, _Traits, _Allocator>&
2728basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, size_type __n, value_type __c)
2729{
2730    size_type __sz = size();
2731    if (__pos > __sz)
2732        this->__throw_out_of_range();
2733    if (__n)
2734    {
2735        size_type __cap = capacity();
2736        value_type* __p;
2737        if (__cap - __sz >= __n)
2738        {
2739            __p = _VSTD::__to_raw_pointer(__get_pointer());
2740            size_type __n_move = __sz - __pos;
2741            if (__n_move != 0)
2742                traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
2743        }
2744        else
2745        {
2746            __grow_by(__cap, __sz + __n - __cap, __sz, __pos, 0, __n);
2747            __p = _VSTD::__to_raw_pointer(__get_long_pointer());
2748        }
2749        traits_type::assign(__p + __pos, __n, __c);
2750        __sz += __n;
2751        __set_size(__sz);
2752        traits_type::assign(__p[__sz], value_type());
2753    }
2754    return *this;
2755}
2756
2757template <class _CharT, class _Traits, class _Allocator>
2758template<class _InputIterator>
2759typename enable_if
2760<
2761     __is_input_iterator  <_InputIterator>::value &&
2762    !__is_forward_iterator<_InputIterator>::value,
2763    typename basic_string<_CharT, _Traits, _Allocator>::iterator
2764>::type
2765basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _InputIterator __first, _InputIterator __last)
2766{
2767#if _LIBCPP_DEBUG_LEVEL >= 2
2768    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
2769        "string::insert(iterator, range) called with an iterator not"
2770        " referring to this string");
2771#endif
2772    size_type __old_sz = size();
2773    difference_type __ip = __pos - begin();
2774    for (; __first != __last; ++__first)
2775        push_back(*__first);
2776    pointer __p = __get_pointer();
2777    _VSTD::rotate(__p + __ip, __p + __old_sz, __p + size());
2778#if _LIBCPP_DEBUG_LEVEL >= 2
2779    return iterator(this, __p + __ip);
2780#else
2781    return iterator(__p + __ip);
2782#endif
2783}
2784
2785template <class _CharT, class _Traits, class _Allocator>
2786template<class _ForwardIterator>
2787typename enable_if
2788<
2789    __is_forward_iterator<_ForwardIterator>::value,
2790    typename basic_string<_CharT, _Traits, _Allocator>::iterator
2791>::type
2792basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last)
2793{
2794#if _LIBCPP_DEBUG_LEVEL >= 2
2795    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
2796        "string::insert(iterator, range) called with an iterator not"
2797        " referring to this string");
2798#endif
2799    size_type __ip = static_cast<size_type>(__pos - begin());
2800    size_type __sz = size();
2801    size_type __cap = capacity();
2802    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
2803    if (__n)
2804    {
2805        value_type* __p;
2806        if (__cap - __sz >= __n)
2807        {
2808            __p = _VSTD::__to_raw_pointer(__get_pointer());
2809            size_type __n_move = __sz - __ip;
2810            if (__n_move != 0)
2811                traits_type::move(__p + __ip + __n, __p + __ip, __n_move);
2812        }
2813        else
2814        {
2815            __grow_by(__cap, __sz + __n - __cap, __sz, __ip, 0, __n);
2816            __p = _VSTD::__to_raw_pointer(__get_long_pointer());
2817        }
2818        __sz += __n;
2819        __set_size(__sz);
2820        traits_type::assign(__p[__sz], value_type());
2821        for (__p += __ip; __first != __last; ++__p, ++__first)
2822            traits_type::assign(*__p, *__first);
2823    }
2824    return begin() + __ip;
2825}
2826
2827template <class _CharT, class _Traits, class _Allocator>
2828inline _LIBCPP_INLINE_VISIBILITY
2829basic_string<_CharT, _Traits, _Allocator>&
2830basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str)
2831{
2832    return insert(__pos1, __str.data(), __str.size());
2833}
2834
2835template <class _CharT, class _Traits, class _Allocator>
2836basic_string<_CharT, _Traits, _Allocator>&
2837basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str,
2838                                                  size_type __pos2, size_type __n)
2839{
2840    size_type __str_sz = __str.size();
2841    if (__pos2 > __str_sz)
2842        this->__throw_out_of_range();
2843    return insert(__pos1, __str.data() + __pos2, _VSTD::min(__n, __str_sz - __pos2));
2844}
2845
2846template <class _CharT, class _Traits, class _Allocator>
2847basic_string<_CharT, _Traits, _Allocator>&
2848basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s)
2849{
2850    _LIBCPP_ASSERT(__s != nullptr, "string::insert received nullptr");
2851    return insert(__pos, __s, traits_type::length(__s));
2852}
2853
2854template <class _CharT, class _Traits, class _Allocator>
2855typename basic_string<_CharT, _Traits, _Allocator>::iterator
2856basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, value_type __c)
2857{
2858    size_type __ip = static_cast<size_type>(__pos - begin());
2859    size_type __sz = size();
2860    size_type __cap = capacity();
2861    value_type* __p;
2862    if (__cap == __sz)
2863    {
2864        __grow_by(__cap, 1, __sz, __ip, 0, 1);
2865        __p = _VSTD::__to_raw_pointer(__get_long_pointer());
2866    }
2867    else
2868    {
2869        __p = _VSTD::__to_raw_pointer(__get_pointer());
2870        size_type __n_move = __sz - __ip;
2871        if (__n_move != 0)
2872            traits_type::move(__p + __ip + 1, __p + __ip, __n_move);
2873    }
2874    traits_type::assign(__p[__ip], __c);
2875    traits_type::assign(__p[++__sz], value_type());
2876    __set_size(__sz);
2877    return begin() + static_cast<difference_type>(__ip);
2878}
2879
2880template <class _CharT, class _Traits, class _Allocator>
2881inline _LIBCPP_INLINE_VISIBILITY
2882typename basic_string<_CharT, _Traits, _Allocator>::iterator
2883basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, size_type __n, value_type __c)
2884{
2885#if _LIBCPP_DEBUG_LEVEL >= 2
2886    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
2887        "string::insert(iterator, n, value) called with an iterator not"
2888        " referring to this string");
2889#endif
2890    difference_type __p = __pos - begin();
2891    insert(static_cast<size_type>(__p), __n, __c);
2892    return begin() + __p;
2893}
2894
2895// replace
2896
2897template <class _CharT, class _Traits, class _Allocator>
2898basic_string<_CharT, _Traits, _Allocator>&
2899basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2)
2900{
2901    _LIBCPP_ASSERT(__n2 == 0 || __s != nullptr, "string::replace received nullptr");
2902    size_type __sz = size();
2903    if (__pos > __sz)
2904        this->__throw_out_of_range();
2905    __n1 = _VSTD::min(__n1, __sz - __pos);
2906    size_type __cap = capacity();
2907    if (__cap - __sz + __n1 >= __n2)
2908    {
2909        value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2910        if (__n1 != __n2)
2911        {
2912            size_type __n_move = __sz - __pos - __n1;
2913            if (__n_move != 0)
2914            {
2915                if (__n1 > __n2)
2916                {
2917                    traits_type::move(__p + __pos, __s, __n2);
2918                    traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
2919                    goto __finish;
2920                }
2921                if (__p + __pos < __s && __s < __p + __sz)
2922                {
2923                    if (__p + __pos + __n1 <= __s)
2924                        __s += __n2 - __n1;
2925                    else // __p + __pos < __s < __p + __pos + __n1
2926                    {
2927                        traits_type::move(__p + __pos, __s, __n1);
2928                        __pos += __n1;
2929                        __s += __n2;
2930                        __n2 -= __n1;
2931                        __n1 = 0;
2932                    }
2933                }
2934                traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
2935            }
2936        }
2937        traits_type::move(__p + __pos, __s, __n2);
2938__finish:
2939        __sz += __n2 - __n1;
2940        __set_size(__sz);
2941        __invalidate_iterators_past(__sz);
2942        traits_type::assign(__p[__sz], value_type());
2943    }
2944    else
2945        __grow_by_and_replace(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2, __s);
2946    return *this;
2947}
2948
2949template <class _CharT, class _Traits, class _Allocator>
2950basic_string<_CharT, _Traits, _Allocator>&
2951basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, size_type __n2, value_type __c)
2952{
2953    size_type __sz = size();
2954    if (__pos > __sz)
2955        this->__throw_out_of_range();
2956    __n1 = _VSTD::min(__n1, __sz - __pos);
2957    size_type __cap = capacity();
2958    value_type* __p;
2959    if (__cap - __sz + __n1 >= __n2)
2960    {
2961        __p = _VSTD::__to_raw_pointer(__get_pointer());
2962        if (__n1 != __n2)
2963        {
2964            size_type __n_move = __sz - __pos - __n1;
2965            if (__n_move != 0)
2966                traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
2967        }
2968    }
2969    else
2970    {
2971        __grow_by(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2);
2972        __p = _VSTD::__to_raw_pointer(__get_long_pointer());
2973    }
2974    traits_type::assign(__p + __pos, __n2, __c);
2975    __sz += __n2 - __n1;
2976    __set_size(__sz);
2977    __invalidate_iterators_past(__sz);
2978    traits_type::assign(__p[__sz], value_type());
2979    return *this;
2980}
2981
2982template <class _CharT, class _Traits, class _Allocator>
2983template<class _InputIterator>
2984typename enable_if
2985<
2986    __is_input_iterator<_InputIterator>::value,
2987    basic_string<_CharT, _Traits, _Allocator>&
2988>::type
2989basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2,
2990                                                   _InputIterator __j1, _InputIterator __j2)
2991{
2992    for (; true; ++__i1, ++__j1)
2993    {
2994        if (__i1 == __i2)
2995        {
2996            if (__j1 != __j2)
2997                insert(__i1, __j1, __j2);
2998            break;
2999        }
3000        if (__j1 == __j2)
3001        {
3002            erase(__i1, __i2);
3003            break;
3004        }
3005        traits_type::assign(const_cast<value_type&>(*__i1), *__j1);
3006    }
3007    return *this;
3008}
3009
3010template <class _CharT, class _Traits, class _Allocator>
3011inline _LIBCPP_INLINE_VISIBILITY
3012basic_string<_CharT, _Traits, _Allocator>&
3013basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const basic_string& __str)
3014{
3015    return replace(__pos1, __n1, __str.data(), __str.size());
3016}
3017
3018template <class _CharT, class _Traits, class _Allocator>
3019basic_string<_CharT, _Traits, _Allocator>&
3020basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const basic_string& __str,
3021                                                   size_type __pos2, size_type __n2)
3022{
3023    size_type __str_sz = __str.size();
3024    if (__pos2 > __str_sz)
3025        this->__throw_out_of_range();
3026    return replace(__pos1, __n1, __str.data() + __pos2, _VSTD::min(__n2, __str_sz - __pos2));
3027}
3028
3029template <class _CharT, class _Traits, class _Allocator>
3030basic_string<_CharT, _Traits, _Allocator>&
3031basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s)
3032{
3033    _LIBCPP_ASSERT(__s != nullptr, "string::replace received nullptr");
3034    return replace(__pos, __n1, __s, traits_type::length(__s));
3035}
3036
3037template <class _CharT, class _Traits, class _Allocator>
3038inline _LIBCPP_INLINE_VISIBILITY
3039basic_string<_CharT, _Traits, _Allocator>&
3040basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const basic_string& __str)
3041{
3042    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1),
3043                   __str.data(), __str.size());
3044}
3045
3046template <class _CharT, class _Traits, class _Allocator>
3047inline _LIBCPP_INLINE_VISIBILITY
3048basic_string<_CharT, _Traits, _Allocator>&
3049basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const value_type* __s, size_type __n)
3050{
3051    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s, __n);
3052}
3053
3054template <class _CharT, class _Traits, class _Allocator>
3055inline _LIBCPP_INLINE_VISIBILITY
3056basic_string<_CharT, _Traits, _Allocator>&
3057basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const value_type* __s)
3058{
3059    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s);
3060}
3061
3062template <class _CharT, class _Traits, class _Allocator>
3063inline _LIBCPP_INLINE_VISIBILITY
3064basic_string<_CharT, _Traits, _Allocator>&
3065basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c)
3066{
3067    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __n, __c);
3068}
3069
3070// erase
3071
3072template <class _CharT, class _Traits, class _Allocator>
3073basic_string<_CharT, _Traits, _Allocator>&
3074basic_string<_CharT, _Traits, _Allocator>::erase(size_type __pos, size_type __n)
3075{
3076    size_type __sz = size();
3077    if (__pos > __sz)
3078        this->__throw_out_of_range();
3079    if (__n)
3080    {
3081        value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
3082        __n = _VSTD::min(__n, __sz - __pos);
3083        size_type __n_move = __sz - __pos - __n;
3084        if (__n_move != 0)
3085            traits_type::move(__p + __pos, __p + __pos + __n, __n_move);
3086        __sz -= __n;
3087        __set_size(__sz);
3088        __invalidate_iterators_past(__sz);
3089        traits_type::assign(__p[__sz], value_type());
3090    }
3091    return *this;
3092}
3093
3094template <class _CharT, class _Traits, class _Allocator>
3095inline _LIBCPP_INLINE_VISIBILITY
3096typename basic_string<_CharT, _Traits, _Allocator>::iterator
3097basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __pos)
3098{
3099#if _LIBCPP_DEBUG_LEVEL >= 2
3100    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
3101        "string::erase(iterator) called with an iterator not"
3102        " referring to this string");
3103#endif
3104    _LIBCPP_ASSERT(__pos != end(),
3105        "string::erase(iterator) called with a non-dereferenceable iterator");
3106    iterator __b = begin();
3107    size_type __r = static_cast<size_type>(__pos - __b);
3108    erase(__r, 1);
3109    return __b + static_cast<difference_type>(__r);
3110}
3111
3112template <class _CharT, class _Traits, class _Allocator>
3113inline _LIBCPP_INLINE_VISIBILITY
3114typename basic_string<_CharT, _Traits, _Allocator>::iterator
3115basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __first, const_iterator __last)
3116{
3117#if _LIBCPP_DEBUG_LEVEL >= 2
3118    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
3119        "string::erase(iterator,  iterator) called with an iterator not"
3120        " referring to this string");
3121#endif
3122    _LIBCPP_ASSERT(__first <= __last, "string::erase(first, last) called with invalid range");
3123    iterator __b = begin();
3124    size_type __r = static_cast<size_type>(__first - __b);
3125    erase(__r, static_cast<size_type>(__last - __first));
3126    return __b + static_cast<difference_type>(__r);
3127}
3128
3129template <class _CharT, class _Traits, class _Allocator>
3130inline _LIBCPP_INLINE_VISIBILITY
3131void
3132basic_string<_CharT, _Traits, _Allocator>::pop_back()
3133{
3134    _LIBCPP_ASSERT(!empty(), "string::pop_back(): string is already empty");
3135    size_type __sz;
3136    if (__is_long())
3137    {
3138        __sz = __get_long_size() - 1;
3139        __set_long_size(__sz);
3140        traits_type::assign(*(__get_long_pointer() + __sz), value_type());
3141    }
3142    else
3143    {
3144        __sz = __get_short_size() - 1;
3145        __set_short_size(__sz);
3146        traits_type::assign(*(__get_short_pointer() + __sz), value_type());
3147    }
3148    __invalidate_iterators_past(__sz);
3149}
3150
3151template <class _CharT, class _Traits, class _Allocator>
3152inline _LIBCPP_INLINE_VISIBILITY
3153void
3154basic_string<_CharT, _Traits, _Allocator>::clear() _NOEXCEPT
3155{
3156    __invalidate_all_iterators();
3157    if (__is_long())
3158    {
3159        traits_type::assign(*__get_long_pointer(), value_type());
3160        __set_long_size(0);
3161    }
3162    else
3163    {
3164        traits_type::assign(*__get_short_pointer(), value_type());
3165        __set_short_size(0);
3166    }
3167}
3168
3169template <class _CharT, class _Traits, class _Allocator>
3170inline _LIBCPP_INLINE_VISIBILITY
3171void
3172basic_string<_CharT, _Traits, _Allocator>::__erase_to_end(size_type __pos)
3173{
3174    if (__is_long())
3175    {
3176        traits_type::assign(*(__get_long_pointer() + __pos), value_type());
3177        __set_long_size(__pos);
3178    }
3179    else
3180    {
3181        traits_type::assign(*(__get_short_pointer() + __pos), value_type());
3182        __set_short_size(__pos);
3183    }
3184    __invalidate_iterators_past(__pos);
3185}
3186
3187template <class _CharT, class _Traits, class _Allocator>
3188void
3189basic_string<_CharT, _Traits, _Allocator>::resize(size_type __n, value_type __c)
3190{
3191    size_type __sz = size();
3192    if (__n > __sz)
3193        append(__n - __sz, __c);
3194    else
3195        __erase_to_end(__n);
3196}
3197
3198template <class _CharT, class _Traits, class _Allocator>
3199inline _LIBCPP_INLINE_VISIBILITY
3200typename basic_string<_CharT, _Traits, _Allocator>::size_type
3201basic_string<_CharT, _Traits, _Allocator>::max_size() const _NOEXCEPT
3202{
3203    size_type __m = __alloc_traits::max_size(__alloc());
3204#if _LIBCPP_BIG_ENDIAN
3205    return (__m <= ~__long_mask ? __m : __m/2) - __alignment;
3206#else
3207    return __m - __alignment;
3208#endif
3209}
3210
3211template <class _CharT, class _Traits, class _Allocator>
3212void
3213basic_string<_CharT, _Traits, _Allocator>::reserve(size_type __res_arg)
3214{
3215    if (__res_arg > max_size())
3216        this->__throw_length_error();
3217    size_type __cap = capacity();
3218    size_type __sz = size();
3219    __res_arg = _VSTD::max(__res_arg, __sz);
3220    __res_arg = __recommend(__res_arg);
3221    if (__res_arg != __cap)
3222    {
3223        pointer __new_data, __p;
3224        bool __was_long, __now_long;
3225        if (__res_arg == __min_cap - 1)
3226        {
3227            __was_long = true;
3228            __now_long = false;
3229            __new_data = __get_short_pointer();
3230            __p = __get_long_pointer();
3231        }
3232        else
3233        {
3234            if (__res_arg > __cap)
3235                __new_data = __alloc_traits::allocate(__alloc(), __res_arg+1);
3236            else
3237            {
3238            #ifndef _LIBCPP_NO_EXCEPTIONS
3239                try
3240                {
3241            #endif  // _LIBCPP_NO_EXCEPTIONS
3242                    __new_data = __alloc_traits::allocate(__alloc(), __res_arg+1);
3243            #ifndef _LIBCPP_NO_EXCEPTIONS
3244                }
3245                catch (...)
3246                {
3247                    return;
3248                }
3249            #else  // _LIBCPP_NO_EXCEPTIONS
3250                if (__new_data == nullptr)
3251                    return;
3252            #endif  // _LIBCPP_NO_EXCEPTIONS
3253            }
3254            __now_long = true;
3255            __was_long = __is_long();
3256            __p = __get_pointer();
3257        }
3258        traits_type::copy(_VSTD::__to_raw_pointer(__new_data),
3259                          _VSTD::__to_raw_pointer(__p), size()+1);
3260        if (__was_long)
3261            __alloc_traits::deallocate(__alloc(), __p, __cap+1);
3262        if (__now_long)
3263        {
3264            __set_long_cap(__res_arg+1);
3265            __set_long_size(__sz);
3266            __set_long_pointer(__new_data);
3267        }
3268        else
3269            __set_short_size(__sz);
3270        __invalidate_all_iterators();
3271    }
3272}
3273
3274template <class _CharT, class _Traits, class _Allocator>
3275inline _LIBCPP_INLINE_VISIBILITY
3276typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3277basic_string<_CharT, _Traits, _Allocator>::operator[](size_type __pos) const
3278{
3279    _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
3280    return *(data() + __pos);
3281}
3282
3283template <class _CharT, class _Traits, class _Allocator>
3284inline _LIBCPP_INLINE_VISIBILITY
3285typename basic_string<_CharT, _Traits, _Allocator>::reference
3286basic_string<_CharT, _Traits, _Allocator>::operator[](size_type __pos)
3287{
3288    _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
3289    return *(__get_pointer() + __pos);
3290}
3291
3292template <class _CharT, class _Traits, class _Allocator>
3293typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3294basic_string<_CharT, _Traits, _Allocator>::at(size_type __n) const
3295{
3296    if (__n >= size())
3297        this->__throw_out_of_range();
3298    return (*this)[__n];
3299}
3300
3301template <class _CharT, class _Traits, class _Allocator>
3302typename basic_string<_CharT, _Traits, _Allocator>::reference
3303basic_string<_CharT, _Traits, _Allocator>::at(size_type __n)
3304{
3305    if (__n >= size())
3306        this->__throw_out_of_range();
3307    return (*this)[__n];
3308}
3309
3310template <class _CharT, class _Traits, class _Allocator>
3311inline _LIBCPP_INLINE_VISIBILITY
3312typename basic_string<_CharT, _Traits, _Allocator>::reference
3313basic_string<_CharT, _Traits, _Allocator>::front()
3314{
3315    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
3316    return *__get_pointer();
3317}
3318
3319template <class _CharT, class _Traits, class _Allocator>
3320inline _LIBCPP_INLINE_VISIBILITY
3321typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3322basic_string<_CharT, _Traits, _Allocator>::front() const
3323{
3324    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
3325    return *data();
3326}
3327
3328template <class _CharT, class _Traits, class _Allocator>
3329inline _LIBCPP_INLINE_VISIBILITY
3330typename basic_string<_CharT, _Traits, _Allocator>::reference
3331basic_string<_CharT, _Traits, _Allocator>::back()
3332{
3333    _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
3334    return *(__get_pointer() + size() - 1);
3335}
3336
3337template <class _CharT, class _Traits, class _Allocator>
3338inline _LIBCPP_INLINE_VISIBILITY
3339typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3340basic_string<_CharT, _Traits, _Allocator>::back() const
3341{
3342    _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
3343    return *(data() + size() - 1);
3344}
3345
3346template <class _CharT, class _Traits, class _Allocator>
3347typename basic_string<_CharT, _Traits, _Allocator>::size_type
3348basic_string<_CharT, _Traits, _Allocator>::copy(value_type* __s, size_type __n, size_type __pos) const
3349{
3350    size_type __sz = size();
3351    if (__pos > __sz)
3352        this->__throw_out_of_range();
3353    size_type __rlen = _VSTD::min(__n, __sz - __pos);
3354    traits_type::copy(__s, data() + __pos, __rlen);
3355    return __rlen;
3356}
3357
3358template <class _CharT, class _Traits, class _Allocator>
3359inline _LIBCPP_INLINE_VISIBILITY
3360basic_string<_CharT, _Traits, _Allocator>
3361basic_string<_CharT, _Traits, _Allocator>::substr(size_type __pos, size_type __n) const
3362{
3363    return basic_string(*this, __pos, __n, __alloc());
3364}
3365
3366template <class _CharT, class _Traits, class _Allocator>
3367inline _LIBCPP_INLINE_VISIBILITY
3368void
3369basic_string<_CharT, _Traits, _Allocator>::swap(basic_string& __str)
3370#if _LIBCPP_STD_VER >= 14
3371        _NOEXCEPT
3372#else
3373        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
3374                    __is_nothrow_swappable<allocator_type>::value)
3375#endif
3376{
3377#if _LIBCPP_DEBUG_LEVEL >= 2
3378    if (!__is_long())
3379        __get_db()->__invalidate_all(this);
3380    if (!__str.__is_long())
3381        __get_db()->__invalidate_all(&__str);
3382    __get_db()->swap(this, &__str);
3383#endif
3384    _VSTD::swap(__r_.first(), __str.__r_.first());
3385    __swap_allocator(__alloc(), __str.__alloc());
3386}
3387
3388// find
3389
3390template <class _Traits>
3391struct _LIBCPP_HIDDEN __traits_eq
3392{
3393    typedef typename _Traits::char_type char_type;
3394    _LIBCPP_INLINE_VISIBILITY
3395    bool operator()(const char_type& __x, const char_type& __y) _NOEXCEPT
3396        {return _Traits::eq(__x, __y);}
3397};
3398
3399template<class _CharT, class _Traits, class _Allocator>
3400typename basic_string<_CharT, _Traits, _Allocator>::size_type
3401basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
3402                                                size_type __pos,
3403                                                size_type __n) const _NOEXCEPT
3404{
3405    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find(): received nullptr");
3406    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3407        (data(), size(), __s, __pos, __n);
3408}
3409
3410template<class _CharT, class _Traits, class _Allocator>
3411inline _LIBCPP_INLINE_VISIBILITY
3412typename basic_string<_CharT, _Traits, _Allocator>::size_type
3413basic_string<_CharT, _Traits, _Allocator>::find(const basic_string& __str,
3414                                                size_type __pos) const _NOEXCEPT
3415{
3416    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3417        (data(), size(), __str.data(), __pos, __str.size());
3418}
3419
3420template<class _CharT, class _Traits, class _Allocator>
3421inline _LIBCPP_INLINE_VISIBILITY
3422typename basic_string<_CharT, _Traits, _Allocator>::size_type
3423basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
3424                                                size_type __pos) const _NOEXCEPT
3425{
3426    _LIBCPP_ASSERT(__s != nullptr, "string::find(): received nullptr");
3427    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3428        (data(), size(), __s, __pos, traits_type::length(__s));
3429}
3430
3431template<class _CharT, class _Traits, class _Allocator>
3432typename basic_string<_CharT, _Traits, _Allocator>::size_type
3433basic_string<_CharT, _Traits, _Allocator>::find(value_type __c,
3434                                                size_type __pos) const _NOEXCEPT
3435{
3436    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3437        (data(), size(), __c, __pos);
3438}
3439
3440// rfind
3441
3442template<class _CharT, class _Traits, class _Allocator>
3443typename basic_string<_CharT, _Traits, _Allocator>::size_type
3444basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
3445                                                 size_type __pos,
3446                                                 size_type __n) const _NOEXCEPT
3447{
3448    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::rfind(): received nullptr");
3449    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3450        (data(), size(), __s, __pos, __n);
3451}
3452
3453template<class _CharT, class _Traits, class _Allocator>
3454inline _LIBCPP_INLINE_VISIBILITY
3455typename basic_string<_CharT, _Traits, _Allocator>::size_type
3456basic_string<_CharT, _Traits, _Allocator>::rfind(const basic_string& __str,
3457                                                 size_type __pos) const _NOEXCEPT
3458{
3459    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3460        (data(), size(), __str.data(), __pos, __str.size());
3461}
3462
3463template<class _CharT, class _Traits, class _Allocator>
3464inline _LIBCPP_INLINE_VISIBILITY
3465typename basic_string<_CharT, _Traits, _Allocator>::size_type
3466basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
3467                                                 size_type __pos) const _NOEXCEPT
3468{
3469    _LIBCPP_ASSERT(__s != nullptr, "string::rfind(): received nullptr");
3470    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3471        (data(), size(), __s, __pos, traits_type::length(__s));
3472}
3473
3474template<class _CharT, class _Traits, class _Allocator>
3475typename basic_string<_CharT, _Traits, _Allocator>::size_type
3476basic_string<_CharT, _Traits, _Allocator>::rfind(value_type __c,
3477                                                 size_type __pos) const _NOEXCEPT
3478{
3479    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3480        (data(), size(), __c, __pos);
3481}
3482
3483// find_first_of
3484
3485template<class _CharT, class _Traits, class _Allocator>
3486typename basic_string<_CharT, _Traits, _Allocator>::size_type
3487basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
3488                                                         size_type __pos,
3489                                                         size_type __n) const _NOEXCEPT
3490{
3491    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_first_of(): received nullptr");
3492    return _VSTD::__str_find_first_of<value_type, size_type, traits_type, npos>
3493        (data(), size(), __s, __pos, __n);
3494}
3495
3496template<class _CharT, class _Traits, class _Allocator>
3497inline _LIBCPP_INLINE_VISIBILITY
3498typename basic_string<_CharT, _Traits, _Allocator>::size_type
3499basic_string<_CharT, _Traits, _Allocator>::find_first_of(const basic_string& __str,
3500                                                         size_type __pos) const _NOEXCEPT
3501{
3502    return _VSTD::__str_find_first_of<value_type, size_type, traits_type, npos>
3503        (data(), size(), __str.data(), __pos, __str.size());
3504}
3505
3506template<class _CharT, class _Traits, class _Allocator>
3507inline _LIBCPP_INLINE_VISIBILITY
3508typename basic_string<_CharT, _Traits, _Allocator>::size_type
3509basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
3510                                                         size_type __pos) const _NOEXCEPT
3511{
3512    _LIBCPP_ASSERT(__s != nullptr, "string::find_first_of(): received nullptr");
3513    return _VSTD::__str_find_first_of<value_type, size_type, traits_type, npos>
3514        (data(), size(), __s, __pos, traits_type::length(__s));
3515}
3516
3517template<class _CharT, class _Traits, class _Allocator>
3518inline _LIBCPP_INLINE_VISIBILITY
3519typename basic_string<_CharT, _Traits, _Allocator>::size_type
3520basic_string<_CharT, _Traits, _Allocator>::find_first_of(value_type __c,
3521                                                         size_type __pos) const _NOEXCEPT
3522{
3523    return find(__c, __pos);
3524}
3525
3526// find_last_of
3527
3528template<class _CharT, class _Traits, class _Allocator>
3529typename basic_string<_CharT, _Traits, _Allocator>::size_type
3530basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
3531                                                        size_type __pos,
3532                                                        size_type __n) const _NOEXCEPT
3533{
3534    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_last_of(): received nullptr");
3535    return _VSTD::__str_find_last_of<value_type, size_type, traits_type, npos>
3536        (data(), size(), __s, __pos, __n);
3537}
3538
3539template<class _CharT, class _Traits, class _Allocator>
3540inline _LIBCPP_INLINE_VISIBILITY
3541typename basic_string<_CharT, _Traits, _Allocator>::size_type
3542basic_string<_CharT, _Traits, _Allocator>::find_last_of(const basic_string& __str,
3543                                                        size_type __pos) const _NOEXCEPT
3544{
3545    return _VSTD::__str_find_last_of<value_type, size_type, traits_type, npos>
3546        (data(), size(), __str.data(), __pos, __str.size());
3547}
3548
3549template<class _CharT, class _Traits, class _Allocator>
3550inline _LIBCPP_INLINE_VISIBILITY
3551typename basic_string<_CharT, _Traits, _Allocator>::size_type
3552basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
3553                                                        size_type __pos) const _NOEXCEPT
3554{
3555    _LIBCPP_ASSERT(__s != nullptr, "string::find_last_of(): received nullptr");
3556    return _VSTD::__str_find_last_of<value_type, size_type, traits_type, npos>
3557        (data(), size(), __s, __pos, traits_type::length(__s));
3558}
3559
3560template<class _CharT, class _Traits, class _Allocator>
3561inline _LIBCPP_INLINE_VISIBILITY
3562typename basic_string<_CharT, _Traits, _Allocator>::size_type
3563basic_string<_CharT, _Traits, _Allocator>::find_last_of(value_type __c,
3564                                                        size_type __pos) const _NOEXCEPT
3565{
3566    return rfind(__c, __pos);
3567}
3568
3569// find_first_not_of
3570
3571template<class _CharT, class _Traits, class _Allocator>
3572typename basic_string<_CharT, _Traits, _Allocator>::size_type
3573basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
3574                                                             size_type __pos,
3575                                                             size_type __n) const _NOEXCEPT
3576{
3577    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_first_not_of(): received nullptr");
3578    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3579        (data(), size(), __s, __pos, __n);
3580}
3581
3582template<class _CharT, class _Traits, class _Allocator>
3583inline _LIBCPP_INLINE_VISIBILITY
3584typename basic_string<_CharT, _Traits, _Allocator>::size_type
3585basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const basic_string& __str,
3586                                                             size_type __pos) const _NOEXCEPT
3587{
3588    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3589        (data(), size(), __str.data(), __pos, __str.size());
3590}
3591
3592template<class _CharT, class _Traits, class _Allocator>
3593inline _LIBCPP_INLINE_VISIBILITY
3594typename basic_string<_CharT, _Traits, _Allocator>::size_type
3595basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
3596                                                             size_type __pos) const _NOEXCEPT
3597{
3598    _LIBCPP_ASSERT(__s != nullptr, "string::find_first_not_of(): received nullptr");
3599    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3600        (data(), size(), __s, __pos, traits_type::length(__s));
3601}
3602
3603template<class _CharT, class _Traits, class _Allocator>
3604inline _LIBCPP_INLINE_VISIBILITY
3605typename basic_string<_CharT, _Traits, _Allocator>::size_type
3606basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(value_type __c,
3607                                                             size_type __pos) const _NOEXCEPT
3608{
3609    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3610        (data(), size(), __c, __pos);
3611}
3612
3613// find_last_not_of
3614
3615template<class _CharT, class _Traits, class _Allocator>
3616typename basic_string<_CharT, _Traits, _Allocator>::size_type
3617basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
3618                                                            size_type __pos,
3619                                                            size_type __n) const _NOEXCEPT
3620{
3621    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_last_not_of(): received nullptr");
3622    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3623        (data(), size(), __s, __pos, __n);
3624}
3625
3626template<class _CharT, class _Traits, class _Allocator>
3627inline _LIBCPP_INLINE_VISIBILITY
3628typename basic_string<_CharT, _Traits, _Allocator>::size_type
3629basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const basic_string& __str,
3630                                                            size_type __pos) const _NOEXCEPT
3631{
3632    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3633        (data(), size(), __str.data(), __pos, __str.size());
3634}
3635
3636template<class _CharT, class _Traits, class _Allocator>
3637inline _LIBCPP_INLINE_VISIBILITY
3638typename basic_string<_CharT, _Traits, _Allocator>::size_type
3639basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
3640                                                            size_type __pos) const _NOEXCEPT
3641{
3642    _LIBCPP_ASSERT(__s != nullptr, "string::find_last_not_of(): received nullptr");
3643    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3644        (data(), size(), __s, __pos, traits_type::length(__s));
3645}
3646
3647template<class _CharT, class _Traits, class _Allocator>
3648inline _LIBCPP_INLINE_VISIBILITY
3649typename basic_string<_CharT, _Traits, _Allocator>::size_type
3650basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(value_type __c,
3651                                                            size_type __pos) const _NOEXCEPT
3652{
3653    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3654        (data(), size(), __c, __pos);
3655}
3656
3657// compare
3658
3659template <class _CharT, class _Traits, class _Allocator>
3660inline _LIBCPP_INLINE_VISIBILITY
3661int
3662basic_string<_CharT, _Traits, _Allocator>::compare(const basic_string& __str) const _NOEXCEPT
3663{
3664    size_t __lhs_sz = size();
3665    size_t __rhs_sz = __str.size();
3666    int __result = traits_type::compare(data(), __str.data(),
3667                                        _VSTD::min(__lhs_sz, __rhs_sz));
3668    if (__result != 0)
3669        return __result;
3670    if (__lhs_sz < __rhs_sz)
3671        return -1;
3672    if (__lhs_sz > __rhs_sz)
3673        return 1;
3674    return 0;
3675}
3676
3677template <class _CharT, class _Traits, class _Allocator>
3678inline _LIBCPP_INLINE_VISIBILITY
3679int
3680basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3681                                                   size_type __n1,
3682                                                   const basic_string& __str) const
3683{
3684    return compare(__pos1, __n1, __str.data(), __str.size());
3685}
3686
3687template <class _CharT, class _Traits, class _Allocator>
3688int
3689basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3690                                                   size_type __n1,
3691                                                   const basic_string& __str,
3692                                                   size_type __pos2,
3693                                                   size_type __n2) const
3694{
3695    size_type __sz = __str.size();
3696    if (__pos2 > __sz)
3697        this->__throw_out_of_range();
3698    return compare(__pos1, __n1, __str.data() + __pos2, _VSTD::min(__n2,
3699                                                                  __sz - __pos2));
3700}
3701
3702template <class _CharT, class _Traits, class _Allocator>
3703int
3704basic_string<_CharT, _Traits, _Allocator>::compare(const value_type* __s) const _NOEXCEPT
3705{
3706    _LIBCPP_ASSERT(__s != nullptr, "string::compare(): received nullptr");
3707    return compare(0, npos, __s, traits_type::length(__s));
3708}
3709
3710template <class _CharT, class _Traits, class _Allocator>
3711int
3712basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3713                                                   size_type __n1,
3714                                                   const value_type* __s) const
3715{
3716    _LIBCPP_ASSERT(__s != nullptr, "string::compare(): received nullptr");
3717    return compare(__pos1, __n1, __s, traits_type::length(__s));
3718}
3719
3720template <class _CharT, class _Traits, class _Allocator>
3721int
3722basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3723                                                   size_type __n1,
3724                                                   const value_type* __s,
3725                                                   size_type __n2) const
3726{
3727    _LIBCPP_ASSERT(__n2 == 0 || __s != nullptr, "string::compare(): received nullptr");
3728    size_type __sz = size();
3729    if (__pos1 > __sz || __n2 == npos)
3730        this->__throw_out_of_range();
3731    size_type __rlen = _VSTD::min(__n1, __sz - __pos1);
3732    int __r = traits_type::compare(data() + __pos1, __s, _VSTD::min(__rlen, __n2));
3733    if (__r == 0)
3734    {
3735        if (__rlen < __n2)
3736            __r = -1;
3737        else if (__rlen > __n2)
3738            __r = 1;
3739    }
3740    return __r;
3741}
3742
3743// __invariants
3744
3745template<class _CharT, class _Traits, class _Allocator>
3746inline _LIBCPP_INLINE_VISIBILITY
3747bool
3748basic_string<_CharT, _Traits, _Allocator>::__invariants() const
3749{
3750    if (size() > capacity())
3751        return false;
3752    if (capacity() < __min_cap - 1)
3753        return false;
3754    if (data() == 0)
3755        return false;
3756    if (data()[size()] != value_type(0))
3757        return false;
3758    return true;
3759}
3760
3761// operator==
3762
3763template<class _CharT, class _Traits, class _Allocator>
3764inline _LIBCPP_INLINE_VISIBILITY
3765bool
3766operator==(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3767           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3768{
3769    size_t __lhs_sz = __lhs.size();
3770    return __lhs_sz == __rhs.size() && _Traits::compare(__lhs.data(),
3771                                                        __rhs.data(),
3772                                                        __lhs_sz) == 0;
3773}
3774
3775template<class _Allocator>
3776inline _LIBCPP_INLINE_VISIBILITY
3777bool
3778operator==(const basic_string<char, char_traits<char>, _Allocator>& __lhs,
3779           const basic_string<char, char_traits<char>, _Allocator>& __rhs) _NOEXCEPT
3780{
3781    size_t __lhs_sz = __lhs.size();
3782    if (__lhs_sz != __rhs.size())
3783        return false;
3784    const char* __lp = __lhs.data();
3785    const char* __rp = __rhs.data();
3786    if (__lhs.__is_long())
3787        return char_traits<char>::compare(__lp, __rp, __lhs_sz) == 0;
3788    for (; __lhs_sz != 0; --__lhs_sz, ++__lp, ++__rp)
3789        if (*__lp != *__rp)
3790            return false;
3791    return true;
3792}
3793
3794template<class _CharT, class _Traits, class _Allocator>
3795inline _LIBCPP_INLINE_VISIBILITY
3796bool
3797operator==(const _CharT* __lhs,
3798           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3799{
3800    typedef basic_string<_CharT, _Traits, _Allocator> _String;
3801    _LIBCPP_ASSERT(__lhs != nullptr, "operator==(char*, basic_string): received nullptr");
3802    size_t __lhs_len = _Traits::length(__lhs);
3803    if (__lhs_len != __rhs.size()) return false;
3804    return __rhs.compare(0, _String::npos, __lhs, __lhs_len) == 0;
3805}
3806
3807template<class _CharT, class _Traits, class _Allocator>
3808inline _LIBCPP_INLINE_VISIBILITY
3809bool
3810operator==(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
3811           const _CharT* __rhs) _NOEXCEPT
3812{
3813    typedef basic_string<_CharT, _Traits, _Allocator> _String;
3814    _LIBCPP_ASSERT(__rhs != nullptr, "operator==(basic_string, char*): received nullptr");
3815    size_t __rhs_len = _Traits::length(__rhs);
3816    if (__rhs_len != __lhs.size()) return false;
3817    return __lhs.compare(0, _String::npos, __rhs, __rhs_len) == 0;
3818}
3819
3820// operator!=
3821
3822template<class _CharT, class _Traits, class _Allocator>
3823inline _LIBCPP_INLINE_VISIBILITY
3824bool
3825operator!=(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
3826           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3827{
3828    return !(__lhs == __rhs);
3829}
3830
3831template<class _CharT, class _Traits, class _Allocator>
3832inline _LIBCPP_INLINE_VISIBILITY
3833bool
3834operator!=(const _CharT* __lhs,
3835           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3836{
3837    return !(__lhs == __rhs);
3838}
3839
3840template<class _CharT, class _Traits, class _Allocator>
3841inline _LIBCPP_INLINE_VISIBILITY
3842bool
3843operator!=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3844           const _CharT* __rhs) _NOEXCEPT
3845{
3846    return !(__lhs == __rhs);
3847}
3848
3849// operator<
3850
3851template<class _CharT, class _Traits, class _Allocator>
3852inline _LIBCPP_INLINE_VISIBILITY
3853bool
3854operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3855           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3856{
3857    return __lhs.compare(__rhs) < 0;
3858}
3859
3860template<class _CharT, class _Traits, class _Allocator>
3861inline _LIBCPP_INLINE_VISIBILITY
3862bool
3863operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3864           const _CharT* __rhs) _NOEXCEPT
3865{
3866    return __lhs.compare(__rhs) < 0;
3867}
3868
3869template<class _CharT, class _Traits, class _Allocator>
3870inline _LIBCPP_INLINE_VISIBILITY
3871bool
3872operator< (const _CharT* __lhs,
3873           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3874{
3875    return __rhs.compare(__lhs) > 0;
3876}
3877
3878// operator>
3879
3880template<class _CharT, class _Traits, class _Allocator>
3881inline _LIBCPP_INLINE_VISIBILITY
3882bool
3883operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3884           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3885{
3886    return __rhs < __lhs;
3887}
3888
3889template<class _CharT, class _Traits, class _Allocator>
3890inline _LIBCPP_INLINE_VISIBILITY
3891bool
3892operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3893           const _CharT* __rhs) _NOEXCEPT
3894{
3895    return __rhs < __lhs;
3896}
3897
3898template<class _CharT, class _Traits, class _Allocator>
3899inline _LIBCPP_INLINE_VISIBILITY
3900bool
3901operator> (const _CharT* __lhs,
3902           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3903{
3904    return __rhs < __lhs;
3905}
3906
3907// operator<=
3908
3909template<class _CharT, class _Traits, class _Allocator>
3910inline _LIBCPP_INLINE_VISIBILITY
3911bool
3912operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3913           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3914{
3915    return !(__rhs < __lhs);
3916}
3917
3918template<class _CharT, class _Traits, class _Allocator>
3919inline _LIBCPP_INLINE_VISIBILITY
3920bool
3921operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3922           const _CharT* __rhs) _NOEXCEPT
3923{
3924    return !(__rhs < __lhs);
3925}
3926
3927template<class _CharT, class _Traits, class _Allocator>
3928inline _LIBCPP_INLINE_VISIBILITY
3929bool
3930operator<=(const _CharT* __lhs,
3931           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3932{
3933    return !(__rhs < __lhs);
3934}
3935
3936// operator>=
3937
3938template<class _CharT, class _Traits, class _Allocator>
3939inline _LIBCPP_INLINE_VISIBILITY
3940bool
3941operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3942           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3943{
3944    return !(__lhs < __rhs);
3945}
3946
3947template<class _CharT, class _Traits, class _Allocator>
3948inline _LIBCPP_INLINE_VISIBILITY
3949bool
3950operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3951           const _CharT* __rhs) _NOEXCEPT
3952{
3953    return !(__lhs < __rhs);
3954}
3955
3956template<class _CharT, class _Traits, class _Allocator>
3957inline _LIBCPP_INLINE_VISIBILITY
3958bool
3959operator>=(const _CharT* __lhs,
3960           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3961{
3962    return !(__lhs < __rhs);
3963}
3964
3965// operator +
3966
3967template<class _CharT, class _Traits, class _Allocator>
3968basic_string<_CharT, _Traits, _Allocator>
3969operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3970          const basic_string<_CharT, _Traits, _Allocator>& __rhs)
3971{
3972    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
3973    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
3974    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
3975    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + __rhs_sz);
3976    __r.append(__rhs.data(), __rhs_sz);
3977    return __r;
3978}
3979
3980template<class _CharT, class _Traits, class _Allocator>
3981basic_string<_CharT, _Traits, _Allocator>
3982operator+(const _CharT* __lhs , const basic_string<_CharT,_Traits,_Allocator>& __rhs)
3983{
3984    basic_string<_CharT, _Traits, _Allocator> __r(__rhs.get_allocator());
3985    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = _Traits::length(__lhs);
3986    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
3987    __r.__init(__lhs, __lhs_sz, __lhs_sz + __rhs_sz);
3988    __r.append(__rhs.data(), __rhs_sz);
3989    return __r;
3990}
3991
3992template<class _CharT, class _Traits, class _Allocator>
3993basic_string<_CharT, _Traits, _Allocator>
3994operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Allocator>& __rhs)
3995{
3996    basic_string<_CharT, _Traits, _Allocator> __r(__rhs.get_allocator());
3997    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
3998    __r.__init(&__lhs, 1, 1 + __rhs_sz);
3999    __r.append(__rhs.data(), __rhs_sz);
4000    return __r;
4001}
4002
4003template<class _CharT, class _Traits, class _Allocator>
4004basic_string<_CharT, _Traits, _Allocator>
4005operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs)
4006{
4007    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
4008    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
4009    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = _Traits::length(__rhs);
4010    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + __rhs_sz);
4011    __r.append(__rhs, __rhs_sz);
4012    return __r;
4013}
4014
4015template<class _CharT, class _Traits, class _Allocator>
4016basic_string<_CharT, _Traits, _Allocator>
4017operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, _CharT __rhs)
4018{
4019    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
4020    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
4021    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + 1);
4022    __r.push_back(__rhs);
4023    return __r;
4024}
4025
4026#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
4027
4028template<class _CharT, class _Traits, class _Allocator>
4029inline _LIBCPP_INLINE_VISIBILITY
4030basic_string<_CharT, _Traits, _Allocator>
4031operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const basic_string<_CharT, _Traits, _Allocator>& __rhs)
4032{
4033    return _VSTD::move(__lhs.append(__rhs));
4034}
4035
4036template<class _CharT, class _Traits, class _Allocator>
4037inline _LIBCPP_INLINE_VISIBILITY
4038basic_string<_CharT, _Traits, _Allocator>
4039operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
4040{
4041    return _VSTD::move(__rhs.insert(0, __lhs));
4042}
4043
4044template<class _CharT, class _Traits, class _Allocator>
4045inline _LIBCPP_INLINE_VISIBILITY
4046basic_string<_CharT, _Traits, _Allocator>
4047operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
4048{
4049    return _VSTD::move(__lhs.append(__rhs));
4050}
4051
4052template<class _CharT, class _Traits, class _Allocator>
4053inline _LIBCPP_INLINE_VISIBILITY
4054basic_string<_CharT, _Traits, _Allocator>
4055operator+(const _CharT* __lhs , basic_string<_CharT,_Traits,_Allocator>&& __rhs)
4056{
4057    return _VSTD::move(__rhs.insert(0, __lhs));
4058}
4059
4060template<class _CharT, class _Traits, class _Allocator>
4061inline _LIBCPP_INLINE_VISIBILITY
4062basic_string<_CharT, _Traits, _Allocator>
4063operator+(_CharT __lhs, basic_string<_CharT,_Traits,_Allocator>&& __rhs)
4064{
4065    __rhs.insert(__rhs.begin(), __lhs);
4066    return _VSTD::move(__rhs);
4067}
4068
4069template<class _CharT, class _Traits, class _Allocator>
4070inline _LIBCPP_INLINE_VISIBILITY
4071basic_string<_CharT, _Traits, _Allocator>
4072operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const _CharT* __rhs)
4073{
4074    return _VSTD::move(__lhs.append(__rhs));
4075}
4076
4077template<class _CharT, class _Traits, class _Allocator>
4078inline _LIBCPP_INLINE_VISIBILITY
4079basic_string<_CharT, _Traits, _Allocator>
4080operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, _CharT __rhs)
4081{
4082    __lhs.push_back(__rhs);
4083    return _VSTD::move(__lhs);
4084}
4085
4086#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
4087
4088// swap
4089
4090template<class _CharT, class _Traits, class _Allocator>
4091inline _LIBCPP_INLINE_VISIBILITY
4092void
4093swap(basic_string<_CharT, _Traits, _Allocator>& __lhs,
4094     basic_string<_CharT, _Traits, _Allocator>& __rhs)
4095     _NOEXCEPT_(_NOEXCEPT_(__lhs.swap(__rhs)))
4096{
4097    __lhs.swap(__rhs);
4098}
4099
4100#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
4101
4102typedef basic_string<char16_t> u16string;
4103typedef basic_string<char32_t> u32string;
4104
4105#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
4106
4107_LIBCPP_FUNC_VIS int                stoi  (const string& __str, size_t* __idx = 0, int __base = 10);
4108_LIBCPP_FUNC_VIS long               stol  (const string& __str, size_t* __idx = 0, int __base = 10);
4109_LIBCPP_FUNC_VIS unsigned long      stoul (const string& __str, size_t* __idx = 0, int __base = 10);
4110_LIBCPP_FUNC_VIS long long          stoll (const string& __str, size_t* __idx = 0, int __base = 10);
4111_LIBCPP_FUNC_VIS unsigned long long stoull(const string& __str, size_t* __idx = 0, int __base = 10);
4112
4113_LIBCPP_FUNC_VIS float       stof (const string& __str, size_t* __idx = 0);
4114_LIBCPP_FUNC_VIS double      stod (const string& __str, size_t* __idx = 0);
4115_LIBCPP_FUNC_VIS long double stold(const string& __str, size_t* __idx = 0);
4116
4117_LIBCPP_FUNC_VIS string to_string(int __val);
4118_LIBCPP_FUNC_VIS string to_string(unsigned __val);
4119_LIBCPP_FUNC_VIS string to_string(long __val);
4120_LIBCPP_FUNC_VIS string to_string(unsigned long __val);
4121_LIBCPP_FUNC_VIS string to_string(long long __val);
4122_LIBCPP_FUNC_VIS string to_string(unsigned long long __val);
4123_LIBCPP_FUNC_VIS string to_string(float __val);
4124_LIBCPP_FUNC_VIS string to_string(double __val);
4125_LIBCPP_FUNC_VIS string to_string(long double __val);
4126
4127_LIBCPP_FUNC_VIS int                stoi  (const wstring& __str, size_t* __idx = 0, int __base = 10);
4128_LIBCPP_FUNC_VIS long               stol  (const wstring& __str, size_t* __idx = 0, int __base = 10);
4129_LIBCPP_FUNC_VIS unsigned long      stoul (const wstring& __str, size_t* __idx = 0, int __base = 10);
4130_LIBCPP_FUNC_VIS long long          stoll (const wstring& __str, size_t* __idx = 0, int __base = 10);
4131_LIBCPP_FUNC_VIS unsigned long long stoull(const wstring& __str, size_t* __idx = 0, int __base = 10);
4132
4133_LIBCPP_FUNC_VIS float       stof (const wstring& __str, size_t* __idx = 0);
4134_LIBCPP_FUNC_VIS double      stod (const wstring& __str, size_t* __idx = 0);
4135_LIBCPP_FUNC_VIS long double stold(const wstring& __str, size_t* __idx = 0);
4136
4137_LIBCPP_FUNC_VIS wstring to_wstring(int __val);
4138_LIBCPP_FUNC_VIS wstring to_wstring(unsigned __val);
4139_LIBCPP_FUNC_VIS wstring to_wstring(long __val);
4140_LIBCPP_FUNC_VIS wstring to_wstring(unsigned long __val);
4141_LIBCPP_FUNC_VIS wstring to_wstring(long long __val);
4142_LIBCPP_FUNC_VIS wstring to_wstring(unsigned long long __val);
4143_LIBCPP_FUNC_VIS wstring to_wstring(float __val);
4144_LIBCPP_FUNC_VIS wstring to_wstring(double __val);
4145_LIBCPP_FUNC_VIS wstring to_wstring(long double __val);
4146
4147template<class _CharT, class _Traits, class _Allocator>
4148    const typename basic_string<_CharT, _Traits, _Allocator>::size_type
4149                   basic_string<_CharT, _Traits, _Allocator>::npos;
4150
4151template<class _CharT, class _Traits, class _Allocator>
4152struct _LIBCPP_TYPE_VIS_ONLY hash<basic_string<_CharT, _Traits, _Allocator> >
4153    : public unary_function<basic_string<_CharT, _Traits, _Allocator>, size_t>
4154{
4155    size_t
4156        operator()(const basic_string<_CharT, _Traits, _Allocator>& __val) const _NOEXCEPT;
4157};
4158
4159template<class _CharT, class _Traits, class _Allocator>
4160size_t
4161hash<basic_string<_CharT, _Traits, _Allocator> >::operator()(
4162        const basic_string<_CharT, _Traits, _Allocator>& __val) const _NOEXCEPT
4163{
4164    return __do_string_hash(__val.data(), __val.data() + __val.size());
4165}
4166
4167template<class _CharT, class _Traits, class _Allocator>
4168basic_ostream<_CharT, _Traits>&
4169operator<<(basic_ostream<_CharT, _Traits>& __os,
4170           const basic_string<_CharT, _Traits, _Allocator>& __str);
4171
4172template<class _CharT, class _Traits, class _Allocator>
4173basic_istream<_CharT, _Traits>&
4174operator>>(basic_istream<_CharT, _Traits>& __is,
4175           basic_string<_CharT, _Traits, _Allocator>& __str);
4176
4177template<class _CharT, class _Traits, class _Allocator>
4178basic_istream<_CharT, _Traits>&
4179getline(basic_istream<_CharT, _Traits>& __is,
4180        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
4181
4182template<class _CharT, class _Traits, class _Allocator>
4183inline _LIBCPP_INLINE_VISIBILITY
4184basic_istream<_CharT, _Traits>&
4185getline(basic_istream<_CharT, _Traits>& __is,
4186        basic_string<_CharT, _Traits, _Allocator>& __str);
4187
4188#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
4189
4190template<class _CharT, class _Traits, class _Allocator>
4191inline _LIBCPP_INLINE_VISIBILITY
4192basic_istream<_CharT, _Traits>&
4193getline(basic_istream<_CharT, _Traits>&& __is,
4194        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
4195
4196template<class _CharT, class _Traits, class _Allocator>
4197inline _LIBCPP_INLINE_VISIBILITY
4198basic_istream<_CharT, _Traits>&
4199getline(basic_istream<_CharT, _Traits>&& __is,
4200        basic_string<_CharT, _Traits, _Allocator>& __str);
4201
4202#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
4203
4204#if _LIBCPP_DEBUG_LEVEL >= 2
4205
4206template<class _CharT, class _Traits, class _Allocator>
4207bool
4208basic_string<_CharT, _Traits, _Allocator>::__dereferenceable(const const_iterator* __i) const
4209{
4210    return this->data() <= _VSTD::__to_raw_pointer(__i->base()) &&
4211           _VSTD::__to_raw_pointer(__i->base()) < this->data() + this->size();
4212}
4213
4214template<class _CharT, class _Traits, class _Allocator>
4215bool
4216basic_string<_CharT, _Traits, _Allocator>::__decrementable(const const_iterator* __i) const
4217{
4218    return this->data() < _VSTD::__to_raw_pointer(__i->base()) &&
4219           _VSTD::__to_raw_pointer(__i->base()) <= this->data() + this->size();
4220}
4221
4222template<class _CharT, class _Traits, class _Allocator>
4223bool
4224basic_string<_CharT, _Traits, _Allocator>::__addable(const const_iterator* __i, ptrdiff_t __n) const
4225{
4226    const value_type* __p = _VSTD::__to_raw_pointer(__i->base()) + __n;
4227    return this->data() <= __p && __p <= this->data() + this->size();
4228}
4229
4230template<class _CharT, class _Traits, class _Allocator>
4231bool
4232basic_string<_CharT, _Traits, _Allocator>::__subscriptable(const const_iterator* __i, ptrdiff_t __n) const
4233{
4234    const value_type* __p = _VSTD::__to_raw_pointer(__i->base()) + __n;
4235    return this->data() <= __p && __p < this->data() + this->size();
4236}
4237
4238#endif  // _LIBCPP_DEBUG_LEVEL >= 2
4239
4240#if _LIBCPP_STD_VER > 11
4241// Literal suffixes for basic_string [basic.string.literals]
4242inline namespace literals
4243{
4244  inline namespace string_literals
4245  {
4246    inline _LIBCPP_INLINE_VISIBILITY
4247    basic_string<char> operator "" s( const char *__str, size_t __len )
4248    {
4249        return basic_string<char> (__str, __len);
4250    }
4251
4252    inline _LIBCPP_INLINE_VISIBILITY
4253    basic_string<wchar_t> operator "" s( const wchar_t *__str, size_t __len )
4254    {
4255        return basic_string<wchar_t> (__str, __len);
4256    }
4257
4258    inline _LIBCPP_INLINE_VISIBILITY
4259    basic_string<char16_t> operator "" s( const char16_t *__str, size_t __len )
4260    {
4261        return basic_string<char16_t> (__str, __len);
4262    }
4263
4264    inline _LIBCPP_INLINE_VISIBILITY
4265    basic_string<char32_t> operator "" s( const char32_t *__str, size_t __len )
4266    {
4267        return basic_string<char32_t> (__str, __len);
4268    }
4269  }
4270}
4271#endif
4272
4273_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS basic_string<char>)
4274_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS basic_string<wchar_t>)
4275_LIBCPP_EXTERN_TEMPLATE(string operator+<char, char_traits<char>, allocator<char> >(char const*, string const&))
4276
4277_LIBCPP_END_NAMESPACE_STD
4278
4279#endif  // _LIBCPP_STRING
4280