xref: /freebsd-12.1/contrib/libc++/include/string (revision f2ee07cf)
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    _LIBCPP_INLINE_VISIBILITY
521    static size_t           length(const char_type* __s);
522    _LIBCPP_INLINE_VISIBILITY
523    static const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
524    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
525    _LIBCPP_INLINE_VISIBILITY
526    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
527    _LIBCPP_INLINE_VISIBILITY
528    static char_type*       assign(char_type* __s, size_t __n, char_type __a);
529
530    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
531        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
532    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
533        {return char_type(__c);}
534    static inline _LIBCPP_CONSTEXPR int_type  to_int_type(char_type __c) _NOEXCEPT
535        {return int_type(__c);}
536    static inline _LIBCPP_CONSTEXPR bool      eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
537        {return __c1 == __c2;}
538    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
539        {return int_type(EOF);}
540};
541
542template <class _CharT>
543int
544char_traits<_CharT>::compare(const char_type* __s1, const char_type* __s2, size_t __n)
545{
546    for (; __n; --__n, ++__s1, ++__s2)
547    {
548        if (lt(*__s1, *__s2))
549            return -1;
550        if (lt(*__s2, *__s1))
551            return 1;
552    }
553    return 0;
554}
555
556template <class _CharT>
557inline
558size_t
559char_traits<_CharT>::length(const char_type* __s)
560{
561    size_t __len = 0;
562    for (; !eq(*__s, char_type(0)); ++__s)
563        ++__len;
564    return __len;
565}
566
567template <class _CharT>
568inline
569const _CharT*
570char_traits<_CharT>::find(const char_type* __s, size_t __n, const char_type& __a)
571{
572    for (; __n; --__n)
573    {
574        if (eq(*__s, __a))
575            return __s;
576        ++__s;
577    }
578    return 0;
579}
580
581template <class _CharT>
582_CharT*
583char_traits<_CharT>::move(char_type* __s1, const char_type* __s2, size_t __n)
584{
585    char_type* __r = __s1;
586    if (__s1 < __s2)
587    {
588        for (; __n; --__n, ++__s1, ++__s2)
589            assign(*__s1, *__s2);
590    }
591    else if (__s2 < __s1)
592    {
593        __s1 += __n;
594        __s2 += __n;
595        for (; __n; --__n)
596            assign(*--__s1, *--__s2);
597    }
598    return __r;
599}
600
601template <class _CharT>
602inline
603_CharT*
604char_traits<_CharT>::copy(char_type* __s1, const char_type* __s2, size_t __n)
605{
606    _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
607    char_type* __r = __s1;
608    for (; __n; --__n, ++__s1, ++__s2)
609        assign(*__s1, *__s2);
610    return __r;
611}
612
613template <class _CharT>
614inline
615_CharT*
616char_traits<_CharT>::assign(char_type* __s, size_t __n, char_type __a)
617{
618    char_type* __r = __s;
619    for (; __n; --__n, ++__s)
620        assign(*__s, __a);
621    return __r;
622}
623
624// char_traits<char>
625
626template <>
627struct _LIBCPP_TYPE_VIS_ONLY char_traits<char>
628{
629    typedef char      char_type;
630    typedef int       int_type;
631    typedef streamoff off_type;
632    typedef streampos pos_type;
633    typedef mbstate_t state_type;
634
635    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
636        {__c1 = __c2;}
637    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
638            {return __c1 == __c2;}
639    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
640        {return (unsigned char)__c1 < (unsigned char)__c2;}
641
642    static inline int compare(const char_type* __s1, const char_type* __s2, size_t __n)
643        {return __n == 0 ? 0 : memcmp(__s1, __s2, __n);}
644    static inline size_t length(const char_type* __s) {return strlen(__s);}
645    static inline const char_type* find(const char_type* __s, size_t __n, const char_type& __a)
646        {return __n == 0 ? NULL : (const char_type*) memchr(__s, to_int_type(__a), __n);}
647    static inline char_type* move(char_type* __s1, const char_type* __s2, size_t __n)
648        {return __n == 0 ? __s1 : (char_type*) memmove(__s1, __s2, __n);}
649    static inline char_type* copy(char_type* __s1, const char_type* __s2, size_t __n)
650        {
651            _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
652            return __n == 0 ? __s1 : (char_type*)memcpy(__s1, __s2, __n);
653        }
654    static inline char_type* assign(char_type* __s, size_t __n, char_type __a)
655        {return __n == 0 ? __s : (char_type*)memset(__s, to_int_type(__a), __n);}
656
657    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
658        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
659    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
660        {return char_type(__c);}
661    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
662        {return int_type((unsigned char)__c);}
663    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
664        {return __c1 == __c2;}
665    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
666        {return int_type(EOF);}
667};
668
669// char_traits<wchar_t>
670
671template <>
672struct _LIBCPP_TYPE_VIS_ONLY char_traits<wchar_t>
673{
674    typedef wchar_t   char_type;
675    typedef wint_t    int_type;
676    typedef streamoff off_type;
677    typedef streampos pos_type;
678    typedef mbstate_t state_type;
679
680    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
681        {__c1 = __c2;}
682    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
683        {return __c1 == __c2;}
684    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
685        {return __c1 < __c2;}
686
687    static inline int compare(const char_type* __s1, const char_type* __s2, size_t __n)
688        {return __n == 0 ? 0 : wmemcmp(__s1, __s2, __n);}
689    static inline size_t length(const char_type* __s)
690        {return wcslen(__s);}
691    static inline const char_type* find(const char_type* __s, size_t __n, const char_type& __a)
692        {return __n == 0 ? NULL : (const char_type*)wmemchr(__s, __a, __n);}
693    static inline char_type* move(char_type* __s1, const char_type* __s2, size_t __n)
694        {return __n == 0 ? __s1 : (char_type*)wmemmove(__s1, __s2, __n);}
695    static inline char_type* copy(char_type* __s1, const char_type* __s2, size_t __n)
696        {
697            _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
698            return __n == 0 ? __s1 : (char_type*)wmemcpy(__s1, __s2, __n);
699        }
700    static inline char_type* assign(char_type* __s, size_t __n, char_type __a)
701        {return __n == 0 ? __s : (char_type*)wmemset(__s, __a, __n);}
702
703    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
704        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
705    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
706        {return char_type(__c);}
707    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
708        {return int_type(__c);}
709    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
710        {return __c1 == __c2;}
711    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
712        {return int_type(WEOF);}
713};
714
715#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
716
717template <>
718struct _LIBCPP_TYPE_VIS_ONLY char_traits<char16_t>
719{
720    typedef char16_t       char_type;
721    typedef uint_least16_t int_type;
722    typedef streamoff      off_type;
723    typedef u16streampos   pos_type;
724    typedef mbstate_t      state_type;
725
726    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
727        {__c1 = __c2;}
728    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
729        {return __c1 == __c2;}
730    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
731        {return __c1 < __c2;}
732
733    _LIBCPP_INLINE_VISIBILITY
734    static int              compare(const char_type* __s1, const char_type* __s2, size_t __n);
735    _LIBCPP_INLINE_VISIBILITY
736    static size_t           length(const char_type* __s);
737    _LIBCPP_INLINE_VISIBILITY
738    static const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
739    _LIBCPP_INLINE_VISIBILITY
740    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
741    _LIBCPP_INLINE_VISIBILITY
742    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
743    _LIBCPP_INLINE_VISIBILITY
744    static char_type*       assign(char_type* __s, size_t __n, char_type __a);
745
746    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
747        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
748    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
749        {return char_type(__c);}
750    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
751        {return int_type(__c);}
752    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
753        {return __c1 == __c2;}
754    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
755        {return int_type(0xFFFF);}
756};
757
758inline
759int
760char_traits<char16_t>::compare(const char_type* __s1, const char_type* __s2, size_t __n)
761{
762    for (; __n; --__n, ++__s1, ++__s2)
763    {
764        if (lt(*__s1, *__s2))
765            return -1;
766        if (lt(*__s2, *__s1))
767            return 1;
768    }
769    return 0;
770}
771
772inline
773size_t
774char_traits<char16_t>::length(const char_type* __s)
775{
776    size_t __len = 0;
777    for (; !eq(*__s, char_type(0)); ++__s)
778        ++__len;
779    return __len;
780}
781
782inline
783const char16_t*
784char_traits<char16_t>::find(const char_type* __s, size_t __n, const char_type& __a)
785{
786    for (; __n; --__n)
787    {
788        if (eq(*__s, __a))
789            return __s;
790        ++__s;
791    }
792    return 0;
793}
794
795inline
796char16_t*
797char_traits<char16_t>::move(char_type* __s1, const char_type* __s2, size_t __n)
798{
799    char_type* __r = __s1;
800    if (__s1 < __s2)
801    {
802        for (; __n; --__n, ++__s1, ++__s2)
803            assign(*__s1, *__s2);
804    }
805    else if (__s2 < __s1)
806    {
807        __s1 += __n;
808        __s2 += __n;
809        for (; __n; --__n)
810            assign(*--__s1, *--__s2);
811    }
812    return __r;
813}
814
815inline
816char16_t*
817char_traits<char16_t>::copy(char_type* __s1, const char_type* __s2, size_t __n)
818{
819    _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
820    char_type* __r = __s1;
821    for (; __n; --__n, ++__s1, ++__s2)
822        assign(*__s1, *__s2);
823    return __r;
824}
825
826inline
827char16_t*
828char_traits<char16_t>::assign(char_type* __s, size_t __n, char_type __a)
829{
830    char_type* __r = __s;
831    for (; __n; --__n, ++__s)
832        assign(*__s, __a);
833    return __r;
834}
835
836template <>
837struct _LIBCPP_TYPE_VIS_ONLY char_traits<char32_t>
838{
839    typedef char32_t       char_type;
840    typedef uint_least32_t int_type;
841    typedef streamoff      off_type;
842    typedef u32streampos   pos_type;
843    typedef mbstate_t      state_type;
844
845    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
846        {__c1 = __c2;}
847    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
848        {return __c1 == __c2;}
849    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
850        {return __c1 < __c2;}
851
852    _LIBCPP_INLINE_VISIBILITY
853    static int              compare(const char_type* __s1, const char_type* __s2, size_t __n);
854    _LIBCPP_INLINE_VISIBILITY
855    static size_t           length(const char_type* __s);
856    _LIBCPP_INLINE_VISIBILITY
857    static const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
858    _LIBCPP_INLINE_VISIBILITY
859    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
860    _LIBCPP_INLINE_VISIBILITY
861    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
862    _LIBCPP_INLINE_VISIBILITY
863    static char_type*       assign(char_type* __s, size_t __n, char_type __a);
864
865    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
866        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
867    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
868        {return char_type(__c);}
869    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
870        {return int_type(__c);}
871    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
872        {return __c1 == __c2;}
873    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
874        {return int_type(0xFFFFFFFF);}
875};
876
877inline
878int
879char_traits<char32_t>::compare(const char_type* __s1, const char_type* __s2, size_t __n)
880{
881    for (; __n; --__n, ++__s1, ++__s2)
882    {
883        if (lt(*__s1, *__s2))
884            return -1;
885        if (lt(*__s2, *__s1))
886            return 1;
887    }
888    return 0;
889}
890
891inline
892size_t
893char_traits<char32_t>::length(const char_type* __s)
894{
895    size_t __len = 0;
896    for (; !eq(*__s, char_type(0)); ++__s)
897        ++__len;
898    return __len;
899}
900
901inline
902const char32_t*
903char_traits<char32_t>::find(const char_type* __s, size_t __n, const char_type& __a)
904{
905    for (; __n; --__n)
906    {
907        if (eq(*__s, __a))
908            return __s;
909        ++__s;
910    }
911    return 0;
912}
913
914inline
915char32_t*
916char_traits<char32_t>::move(char_type* __s1, const char_type* __s2, size_t __n)
917{
918    char_type* __r = __s1;
919    if (__s1 < __s2)
920    {
921        for (; __n; --__n, ++__s1, ++__s2)
922            assign(*__s1, *__s2);
923    }
924    else if (__s2 < __s1)
925    {
926        __s1 += __n;
927        __s2 += __n;
928        for (; __n; --__n)
929            assign(*--__s1, *--__s2);
930    }
931    return __r;
932}
933
934inline
935char32_t*
936char_traits<char32_t>::copy(char_type* __s1, const char_type* __s2, size_t __n)
937{
938    _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
939    char_type* __r = __s1;
940    for (; __n; --__n, ++__s1, ++__s2)
941        assign(*__s1, *__s2);
942    return __r;
943}
944
945inline
946char32_t*
947char_traits<char32_t>::assign(char_type* __s, size_t __n, char_type __a)
948{
949    char_type* __r = __s;
950    for (; __n; --__n, ++__s)
951        assign(*__s, __a);
952    return __r;
953}
954
955#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
956
957// helper fns for basic_string
958
959// __str_find
960template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
961_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
962__str_find(const _CharT *__p, _SizeT __sz,
963             _CharT __c, _SizeT __pos) _NOEXCEPT
964{
965    if (__pos >= __sz)
966        return __npos;
967    const _CharT* __r = _Traits::find(__p + __pos, __sz - __pos, __c);
968    if (__r == 0)
969        return __npos;
970    return static_cast<_SizeT>(__r - __p);
971}
972
973template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
974_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
975__str_find(const _CharT *__p, _SizeT __sz,
976       const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
977{
978    if (__pos > __sz || __sz - __pos < __n)
979        return __npos;
980    if (__n == 0)
981        return __pos;
982    const _CharT* __r =
983        _VSTD::__search(__p + __pos, __p + __sz,
984                        __s, __s + __n, _Traits::eq,
985                        random_access_iterator_tag(), random_access_iterator_tag());
986    if (__r == __p + __sz)
987        return __npos;
988    return static_cast<_SizeT>(__r - __p);
989}
990
991
992// __str_rfind
993
994template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
995_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
996__str_rfind(const _CharT *__p, _SizeT __sz,
997              _CharT __c, _SizeT __pos) _NOEXCEPT
998{
999    if (__sz < 1)
1000        return __npos;
1001    if (__pos < __sz)
1002        ++__pos;
1003    else
1004        __pos = __sz;
1005    for (const _CharT* __ps = __p + __pos; __ps != __p;)
1006    {
1007        if (_Traits::eq(*--__ps, __c))
1008            return static_cast<_SizeT>(__ps - __p);
1009    }
1010    return __npos;
1011}
1012
1013template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1014_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1015__str_rfind(const _CharT *__p, _SizeT __sz,
1016        const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1017{
1018    __pos = _VSTD::min(__pos, __sz);
1019    if (__n < __sz - __pos)
1020        __pos += __n;
1021    else
1022        __pos = __sz;
1023    const _CharT* __r = _VSTD::__find_end(
1024                  __p, __p + __pos, __s, __s + __n, _Traits::eq,
1025                        random_access_iterator_tag(), random_access_iterator_tag());
1026    if (__n > 0 && __r == __p + __pos)
1027        return __npos;
1028    return static_cast<_SizeT>(__r - __p);
1029}
1030
1031// __str_find_first_of
1032template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1033_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1034__str_find_first_of(const _CharT *__p, _SizeT __sz,
1035                const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1036{
1037    if (__pos >= __sz || __n == 0)
1038        return __npos;
1039    const _CharT* __r = _VSTD::__find_first_of_ce
1040        (__p + __pos, __p + __sz, __s, __s + __n, _Traits::eq );
1041    if (__r == __p + __sz)
1042        return __npos;
1043    return static_cast<_SizeT>(__r - __p);
1044}
1045
1046
1047// __str_find_last_of
1048template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1049_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1050__str_find_last_of(const _CharT *__p, _SizeT __sz,
1051               const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1052    {
1053    if (__n != 0)
1054    {
1055        if (__pos < __sz)
1056            ++__pos;
1057        else
1058            __pos = __sz;
1059        for (const _CharT* __ps = __p + __pos; __ps != __p;)
1060        {
1061            const _CharT* __r = _Traits::find(__s, __n, *--__ps);
1062            if (__r)
1063                return static_cast<_SizeT>(__ps - __p);
1064        }
1065    }
1066    return __npos;
1067}
1068
1069
1070// __str_find_first_not_of
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                    const _CharT* __s, _SizeT __pos, _SizeT __n) _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::find(__s, __n, *__ps) == 0)
1081                return static_cast<_SizeT>(__ps - __p);
1082    }
1083    return __npos;
1084}
1085
1086
1087template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1088_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1089__str_find_first_not_of(const _CharT *__p, _SizeT __sz,
1090                          _CharT __c, _SizeT __pos) _NOEXCEPT
1091{
1092    if (__pos < __sz)
1093    {
1094        const _CharT* __pe = __p + __sz;
1095        for (const _CharT* __ps = __p + __pos; __ps != __pe; ++__ps)
1096            if (!_Traits::eq(*__ps, __c))
1097                return static_cast<_SizeT>(__ps - __p);
1098    }
1099    return __npos;
1100}
1101
1102
1103// __str_find_last_not_of
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                   const _CharT* __s, _SizeT __pos, _SizeT __n) _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::find(__s, __n, *--__ps) == 0)
1115            return static_cast<_SizeT>(__ps - __p);
1116    return __npos;
1117}
1118
1119
1120template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1121_SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1122__str_find_last_not_of(const _CharT *__p, _SizeT __sz,
1123                         _CharT __c, _SizeT __pos) _NOEXCEPT
1124{
1125    if (__pos < __sz)
1126        ++__pos;
1127    else
1128        __pos = __sz;
1129    for (const _CharT* __ps = __p + __pos; __ps != __p;)
1130        if (!_Traits::eq(*--__ps, __c))
1131            return static_cast<_SizeT>(__ps - __p);
1132    return __npos;
1133}
1134
1135template<class _Ptr>
1136size_t _LIBCPP_INLINE_VISIBILITY __do_string_hash(_Ptr __p, _Ptr __e)
1137{
1138    typedef typename iterator_traits<_Ptr>::value_type value_type;
1139    return __murmur2_or_cityhash<size_t>()(__p, (__e-__p)*sizeof(value_type));
1140}
1141
1142// basic_string
1143
1144template<class _CharT, class _Traits, class _Allocator>
1145basic_string<_CharT, _Traits, _Allocator>
1146operator+(const basic_string<_CharT, _Traits, _Allocator>& __x,
1147          const basic_string<_CharT, _Traits, _Allocator>& __y);
1148
1149template<class _CharT, class _Traits, class _Allocator>
1150basic_string<_CharT, _Traits, _Allocator>
1151operator+(const _CharT* __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
1152
1153template<class _CharT, class _Traits, class _Allocator>
1154basic_string<_CharT, _Traits, _Allocator>
1155operator+(_CharT __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
1156
1157template<class _CharT, class _Traits, class _Allocator>
1158basic_string<_CharT, _Traits, _Allocator>
1159operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, const _CharT* __y);
1160
1161template<class _CharT, class _Traits, class _Allocator>
1162basic_string<_CharT, _Traits, _Allocator>
1163operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, _CharT __y);
1164
1165template <bool>
1166class _LIBCPP_TYPE_VIS_ONLY __basic_string_common
1167{
1168protected:
1169    void __throw_length_error() const;
1170    void __throw_out_of_range() const;
1171};
1172
1173template <bool __b>
1174void
1175__basic_string_common<__b>::__throw_length_error() const
1176{
1177#ifndef _LIBCPP_NO_EXCEPTIONS
1178    throw length_error("basic_string");
1179#else
1180    assert(!"basic_string length_error");
1181#endif
1182}
1183
1184template <bool __b>
1185void
1186__basic_string_common<__b>::__throw_out_of_range() const
1187{
1188#ifndef _LIBCPP_NO_EXCEPTIONS
1189    throw out_of_range("basic_string");
1190#else
1191    assert(!"basic_string out_of_range");
1192#endif
1193}
1194
1195#ifdef _LIBCPP_MSVC
1196#pragma warning( push )
1197#pragma warning( disable: 4231 )
1198#endif // _LIBCPP_MSVC
1199_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS __basic_string_common<true>)
1200#ifdef _LIBCPP_MSVC
1201#pragma warning( pop )
1202#endif // _LIBCPP_MSVC
1203
1204#ifdef _LIBCPP_NO_EXCEPTIONS
1205template <class _Iter>
1206struct __libcpp_string_gets_noexcept_iterator_impl : public true_type {};
1207#elif defined(_LIBCPP_HAS_NO_NOEXCEPT)
1208template <class _Iter>
1209struct __libcpp_string_gets_noexcept_iterator_impl : public false_type {};
1210#else
1211template <class _Iter, bool = __is_forward_iterator<_Iter>::value>
1212struct __libcpp_string_gets_noexcept_iterator_impl : public _LIBCPP_BOOL_CONSTANT((
1213    noexcept(++(declval<_Iter&>())) &&
1214    is_nothrow_assignable<_Iter&, _Iter>::value &&
1215    noexcept(declval<_Iter>() == declval<_Iter>()) &&
1216    noexcept(*declval<_Iter>())
1217)) {};
1218
1219template <class _Iter>
1220struct __libcpp_string_gets_noexcept_iterator_impl<_Iter, false> : public false_type {};
1221#endif
1222
1223
1224template <class _Iter>
1225struct __libcpp_string_gets_noexcept_iterator
1226    : public _LIBCPP_BOOL_CONSTANT(__libcpp_is_trivial_iterator<_Iter>::value || __libcpp_string_gets_noexcept_iterator_impl<_Iter>::value) {};
1227
1228#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1229
1230template <class _CharT, size_t = sizeof(_CharT)>
1231struct __padding
1232{
1233    unsigned char __xx[sizeof(_CharT)-1];
1234};
1235
1236template <class _CharT>
1237struct __padding<_CharT, 1>
1238{
1239};
1240
1241#endif  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1242
1243template<class _CharT, class _Traits, class _Allocator>
1244class _LIBCPP_TYPE_VIS_ONLY basic_string
1245    : private __basic_string_common<true>
1246{
1247public:
1248    typedef basic_string                                 __self;
1249    typedef _Traits                                      traits_type;
1250    typedef typename traits_type::char_type              value_type;
1251    typedef _Allocator                                   allocator_type;
1252    typedef allocator_traits<allocator_type>             __alloc_traits;
1253    typedef typename __alloc_traits::size_type           size_type;
1254    typedef typename __alloc_traits::difference_type     difference_type;
1255    typedef value_type&                                  reference;
1256    typedef const value_type&                            const_reference;
1257    typedef typename __alloc_traits::pointer             pointer;
1258    typedef typename __alloc_traits::const_pointer       const_pointer;
1259
1260    static_assert(is_pod<value_type>::value, "Character type of basic_string must be a POD");
1261    static_assert((is_same<_CharT, value_type>::value),
1262                  "traits_type::char_type must be the same type as CharT");
1263    static_assert((is_same<typename allocator_type::value_type, value_type>::value),
1264                  "Allocator::value_type must be same type as value_type");
1265#if defined(_LIBCPP_RAW_ITERATORS)
1266    typedef pointer                                      iterator;
1267    typedef const_pointer                                const_iterator;
1268#else  // defined(_LIBCPP_RAW_ITERATORS)
1269    typedef __wrap_iter<pointer>                         iterator;
1270    typedef __wrap_iter<const_pointer>                   const_iterator;
1271#endif  // defined(_LIBCPP_RAW_ITERATORS)
1272    typedef _VSTD::reverse_iterator<iterator>             reverse_iterator;
1273    typedef _VSTD::reverse_iterator<const_iterator>       const_reverse_iterator;
1274
1275private:
1276
1277#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1278
1279    struct __long
1280    {
1281        pointer   __data_;
1282        size_type __size_;
1283        size_type __cap_;
1284    };
1285
1286#if _LIBCPP_BIG_ENDIAN
1287    enum {__short_mask = 0x01};
1288    enum {__long_mask  = 0x1ul};
1289#else  // _LIBCPP_BIG_ENDIAN
1290    enum {__short_mask = 0x80};
1291    enum {__long_mask  = ~(size_type(~0) >> 1)};
1292#endif  // _LIBCPP_BIG_ENDIAN
1293
1294    enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
1295                      (sizeof(__long) - 1)/sizeof(value_type) : 2};
1296
1297    struct __short
1298    {
1299        value_type __data_[__min_cap];
1300        struct
1301            : __padding<value_type>
1302        {
1303            unsigned char __size_;
1304        };
1305    };
1306
1307#else
1308
1309    struct __long
1310    {
1311        size_type __cap_;
1312        size_type __size_;
1313        pointer   __data_;
1314    };
1315
1316#if _LIBCPP_BIG_ENDIAN
1317    enum {__short_mask = 0x80};
1318    enum {__long_mask  = ~(size_type(~0) >> 1)};
1319#else  // _LIBCPP_BIG_ENDIAN
1320    enum {__short_mask = 0x01};
1321    enum {__long_mask  = 0x1ul};
1322#endif  // _LIBCPP_BIG_ENDIAN
1323
1324    enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
1325                      (sizeof(__long) - 1)/sizeof(value_type) : 2};
1326
1327    struct __short
1328    {
1329        union
1330        {
1331            unsigned char __size_;
1332            value_type __lx;
1333        };
1334        value_type __data_[__min_cap];
1335    };
1336
1337#endif  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1338
1339    union __ulx{__long __lx; __short __lxx;};
1340
1341    enum {__n_words = sizeof(__ulx) / sizeof(size_type)};
1342
1343    struct __raw
1344    {
1345        size_type __words[__n_words];
1346    };
1347
1348    struct __rep
1349    {
1350        union
1351        {
1352            __long  __l;
1353            __short __s;
1354            __raw   __r;
1355        };
1356    };
1357
1358    __compressed_pair<__rep, allocator_type> __r_;
1359
1360public:
1361    static const size_type npos = -1;
1362
1363    _LIBCPP_INLINE_VISIBILITY basic_string()
1364        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value);
1365
1366    _LIBCPP_INLINE_VISIBILITY explicit basic_string(const allocator_type& __a)
1367#if _LIBCPP_STD_VER <= 14
1368        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value);
1369#else
1370        _NOEXCEPT;
1371#endif
1372
1373    basic_string(const basic_string& __str);
1374    basic_string(const basic_string& __str, const allocator_type& __a);
1375
1376#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1377    _LIBCPP_INLINE_VISIBILITY
1378    basic_string(basic_string&& __str)
1379#if _LIBCPP_STD_VER <= 14
1380        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
1381#else
1382        _NOEXCEPT;
1383#endif
1384
1385    _LIBCPP_INLINE_VISIBILITY
1386    basic_string(basic_string&& __str, const allocator_type& __a);
1387#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
1388    _LIBCPP_INLINE_VISIBILITY basic_string(const value_type* __s);
1389    _LIBCPP_INLINE_VISIBILITY
1390    basic_string(const value_type* __s, const allocator_type& __a);
1391    _LIBCPP_INLINE_VISIBILITY
1392    basic_string(const value_type* __s, size_type __n);
1393    _LIBCPP_INLINE_VISIBILITY
1394    basic_string(const value_type* __s, size_type __n, const allocator_type& __a);
1395    _LIBCPP_INLINE_VISIBILITY
1396    basic_string(size_type __n, value_type __c);
1397    _LIBCPP_INLINE_VISIBILITY
1398    basic_string(size_type __n, value_type __c, const allocator_type& __a);
1399    basic_string(const basic_string& __str, size_type __pos, size_type __n = npos,
1400                 const allocator_type& __a = allocator_type());
1401    template<class _InputIterator>
1402        _LIBCPP_INLINE_VISIBILITY
1403        basic_string(_InputIterator __first, _InputIterator __last);
1404    template<class _InputIterator>
1405        _LIBCPP_INLINE_VISIBILITY
1406        basic_string(_InputIterator __first, _InputIterator __last, const allocator_type& __a);
1407#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1408    _LIBCPP_INLINE_VISIBILITY
1409    basic_string(initializer_list<value_type> __il);
1410    _LIBCPP_INLINE_VISIBILITY
1411    basic_string(initializer_list<value_type> __il, const allocator_type& __a);
1412#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1413
1414    ~basic_string();
1415
1416    basic_string& operator=(const basic_string& __str);
1417#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1418    _LIBCPP_INLINE_VISIBILITY
1419    basic_string& operator=(basic_string&& __str)
1420        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value));
1421#endif
1422    _LIBCPP_INLINE_VISIBILITY basic_string& operator=(const value_type* __s) {return assign(__s);}
1423    basic_string& operator=(value_type __c);
1424#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1425    _LIBCPP_INLINE_VISIBILITY
1426    basic_string& operator=(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
1427#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1428
1429#if _LIBCPP_DEBUG_LEVEL >= 2
1430    _LIBCPP_INLINE_VISIBILITY
1431    iterator begin() _NOEXCEPT
1432        {return iterator(this, __get_pointer());}
1433    _LIBCPP_INLINE_VISIBILITY
1434    const_iterator begin() const _NOEXCEPT
1435        {return const_iterator(this, __get_pointer());}
1436    _LIBCPP_INLINE_VISIBILITY
1437    iterator end() _NOEXCEPT
1438        {return iterator(this, __get_pointer() + size());}
1439    _LIBCPP_INLINE_VISIBILITY
1440    const_iterator end() const _NOEXCEPT
1441        {return const_iterator(this, __get_pointer() + size());}
1442#else
1443    _LIBCPP_INLINE_VISIBILITY
1444    iterator begin() _NOEXCEPT
1445        {return iterator(__get_pointer());}
1446    _LIBCPP_INLINE_VISIBILITY
1447    const_iterator begin() const _NOEXCEPT
1448        {return const_iterator(__get_pointer());}
1449    _LIBCPP_INLINE_VISIBILITY
1450    iterator end() _NOEXCEPT
1451        {return iterator(__get_pointer() + size());}
1452    _LIBCPP_INLINE_VISIBILITY
1453    const_iterator end() const _NOEXCEPT
1454        {return const_iterator(__get_pointer() + size());}
1455#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1456    _LIBCPP_INLINE_VISIBILITY
1457    reverse_iterator rbegin() _NOEXCEPT
1458        {return reverse_iterator(end());}
1459    _LIBCPP_INLINE_VISIBILITY
1460    const_reverse_iterator rbegin() const _NOEXCEPT
1461        {return const_reverse_iterator(end());}
1462    _LIBCPP_INLINE_VISIBILITY
1463    reverse_iterator rend() _NOEXCEPT
1464        {return reverse_iterator(begin());}
1465    _LIBCPP_INLINE_VISIBILITY
1466    const_reverse_iterator rend() const _NOEXCEPT
1467        {return const_reverse_iterator(begin());}
1468
1469    _LIBCPP_INLINE_VISIBILITY
1470    const_iterator cbegin() const _NOEXCEPT
1471        {return begin();}
1472    _LIBCPP_INLINE_VISIBILITY
1473    const_iterator cend() const _NOEXCEPT
1474        {return end();}
1475    _LIBCPP_INLINE_VISIBILITY
1476    const_reverse_iterator crbegin() const _NOEXCEPT
1477        {return rbegin();}
1478    _LIBCPP_INLINE_VISIBILITY
1479    const_reverse_iterator crend() const _NOEXCEPT
1480        {return rend();}
1481
1482    _LIBCPP_INLINE_VISIBILITY size_type size() const _NOEXCEPT
1483        {return __is_long() ? __get_long_size() : __get_short_size();}
1484    _LIBCPP_INLINE_VISIBILITY size_type length() const _NOEXCEPT {return size();}
1485    _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT;
1486    _LIBCPP_INLINE_VISIBILITY size_type capacity() const _NOEXCEPT
1487        {return (__is_long() ? __get_long_cap()
1488                             : static_cast<size_type>(__min_cap)) - 1;}
1489
1490    void resize(size_type __n, value_type __c);
1491    _LIBCPP_INLINE_VISIBILITY void resize(size_type __n) {resize(__n, value_type());}
1492
1493    void reserve(size_type res_arg = 0);
1494    _LIBCPP_INLINE_VISIBILITY
1495    void shrink_to_fit() _NOEXCEPT {reserve();}
1496    _LIBCPP_INLINE_VISIBILITY
1497    void clear() _NOEXCEPT;
1498    _LIBCPP_INLINE_VISIBILITY bool empty() const _NOEXCEPT {return size() == 0;}
1499
1500    _LIBCPP_INLINE_VISIBILITY const_reference operator[](size_type __pos) const;
1501    _LIBCPP_INLINE_VISIBILITY reference       operator[](size_type __pos);
1502
1503    const_reference at(size_type __n) const;
1504    reference       at(size_type __n);
1505
1506    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(const basic_string& __str) {return append(__str);}
1507    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(const value_type* __s)         {return append(__s);}
1508    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(value_type __c)            {push_back(__c); return *this;}
1509#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1510    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(initializer_list<value_type> __il) {return append(__il);}
1511#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1512
1513    _LIBCPP_INLINE_VISIBILITY
1514    basic_string& append(const basic_string& __str);
1515    basic_string& append(const basic_string& __str, size_type __pos, size_type __n=npos);
1516    basic_string& append(const value_type* __s, size_type __n);
1517    basic_string& append(const value_type* __s);
1518    basic_string& append(size_type __n, value_type __c);
1519    template<class _InputIterator>
1520        typename enable_if
1521        <
1522            __is_exactly_input_iterator<_InputIterator>::value
1523                || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
1524            basic_string&
1525        >::type
1526        append(_InputIterator __first, _InputIterator __last);
1527    template<class _ForwardIterator>
1528        typename enable_if
1529        <
1530            __is_forward_iterator<_ForwardIterator>::value
1531                && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
1532            basic_string&
1533        >::type
1534        append(_ForwardIterator __first, _ForwardIterator __last);
1535#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1536    _LIBCPP_INLINE_VISIBILITY
1537    basic_string& append(initializer_list<value_type> __il) {return append(__il.begin(), __il.size());}
1538#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1539
1540    void push_back(value_type __c);
1541    _LIBCPP_INLINE_VISIBILITY
1542    void pop_back();
1543    _LIBCPP_INLINE_VISIBILITY reference       front();
1544    _LIBCPP_INLINE_VISIBILITY const_reference front() const;
1545    _LIBCPP_INLINE_VISIBILITY reference       back();
1546    _LIBCPP_INLINE_VISIBILITY const_reference back() const;
1547
1548    _LIBCPP_INLINE_VISIBILITY
1549    basic_string& assign(const basic_string& __str);
1550#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1551    _LIBCPP_INLINE_VISIBILITY
1552    basic_string& assign(basic_string&& str)
1553        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
1554        {*this = _VSTD::move(str); return *this;}
1555#endif
1556    basic_string& assign(const basic_string& __str, size_type __pos, size_type __n=npos);
1557    basic_string& assign(const value_type* __s, size_type __n);
1558    basic_string& assign(const value_type* __s);
1559    basic_string& assign(size_type __n, value_type __c);
1560    template<class _InputIterator>
1561        typename enable_if
1562        <
1563           __is_exactly_input_iterator<_InputIterator>::value
1564                || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
1565            basic_string&
1566        >::type
1567        assign(_InputIterator __first, _InputIterator __last);
1568    template<class _ForwardIterator>
1569        typename enable_if
1570        <
1571            __is_forward_iterator<_ForwardIterator>::value
1572                 && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
1573            basic_string&
1574        >::type
1575        assign(_ForwardIterator __first, _ForwardIterator __last);
1576#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1577    _LIBCPP_INLINE_VISIBILITY
1578    basic_string& assign(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
1579#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1580
1581    _LIBCPP_INLINE_VISIBILITY
1582    basic_string& insert(size_type __pos1, const basic_string& __str);
1583    basic_string& insert(size_type __pos1, const basic_string& __str, size_type __pos2, size_type __n=npos);
1584    basic_string& insert(size_type __pos, const value_type* __s, size_type __n);
1585    basic_string& insert(size_type __pos, const value_type* __s);
1586    basic_string& insert(size_type __pos, size_type __n, value_type __c);
1587    iterator      insert(const_iterator __pos, value_type __c);
1588    _LIBCPP_INLINE_VISIBILITY
1589    iterator      insert(const_iterator __pos, size_type __n, value_type __c);
1590    template<class _InputIterator>
1591        typename enable_if
1592        <
1593           __is_exactly_input_iterator<_InputIterator>::value
1594                || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
1595            iterator
1596        >::type
1597        insert(const_iterator __pos, _InputIterator __first, _InputIterator __last);
1598    template<class _ForwardIterator>
1599        typename enable_if
1600        <
1601            __is_forward_iterator<_ForwardIterator>::value
1602                 && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
1603            iterator
1604        >::type
1605        insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last);
1606#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1607    _LIBCPP_INLINE_VISIBILITY
1608    iterator insert(const_iterator __pos, initializer_list<value_type> __il)
1609                    {return insert(__pos, __il.begin(), __il.end());}
1610#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1611
1612    basic_string& erase(size_type __pos = 0, size_type __n = npos);
1613    _LIBCPP_INLINE_VISIBILITY
1614    iterator      erase(const_iterator __pos);
1615    _LIBCPP_INLINE_VISIBILITY
1616    iterator      erase(const_iterator __first, const_iterator __last);
1617
1618    _LIBCPP_INLINE_VISIBILITY
1619    basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str);
1620    basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos);
1621    basic_string& replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2);
1622    basic_string& replace(size_type __pos, size_type __n1, const value_type* __s);
1623    basic_string& replace(size_type __pos, size_type __n1, size_type __n2, value_type __c);
1624    _LIBCPP_INLINE_VISIBILITY
1625    basic_string& replace(const_iterator __i1, const_iterator __i2, const basic_string& __str);
1626    _LIBCPP_INLINE_VISIBILITY
1627    basic_string& replace(const_iterator __i1, const_iterator __i2, const value_type* __s, size_type __n);
1628    _LIBCPP_INLINE_VISIBILITY
1629    basic_string& replace(const_iterator __i1, const_iterator __i2, const value_type* __s);
1630    _LIBCPP_INLINE_VISIBILITY
1631    basic_string& replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c);
1632    template<class _InputIterator>
1633        typename enable_if
1634        <
1635            __is_input_iterator<_InputIterator>::value,
1636            basic_string&
1637        >::type
1638        replace(const_iterator __i1, const_iterator __i2, _InputIterator __j1, _InputIterator __j2);
1639#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1640    _LIBCPP_INLINE_VISIBILITY
1641    basic_string& replace(const_iterator __i1, const_iterator __i2, initializer_list<value_type> __il)
1642        {return replace(__i1, __i2, __il.begin(), __il.end());}
1643#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1644
1645    size_type copy(value_type* __s, size_type __n, size_type __pos = 0) const;
1646    _LIBCPP_INLINE_VISIBILITY
1647    basic_string substr(size_type __pos = 0, size_type __n = npos) const;
1648
1649    _LIBCPP_INLINE_VISIBILITY
1650    void swap(basic_string& __str)
1651#if _LIBCPP_STD_VER >= 14
1652        _NOEXCEPT;
1653#else
1654        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
1655                    __is_nothrow_swappable<allocator_type>::value);
1656#endif
1657
1658    _LIBCPP_INLINE_VISIBILITY
1659    const value_type* c_str() const _NOEXCEPT {return data();}
1660    _LIBCPP_INLINE_VISIBILITY
1661    const value_type* data() const _NOEXCEPT  {return _VSTD::__to_raw_pointer(__get_pointer());}
1662
1663    _LIBCPP_INLINE_VISIBILITY
1664    allocator_type get_allocator() const _NOEXCEPT {return __alloc();}
1665
1666    _LIBCPP_INLINE_VISIBILITY
1667    size_type find(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
1668    size_type find(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1669    _LIBCPP_INLINE_VISIBILITY
1670    size_type find(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
1671    size_type find(value_type __c, size_type __pos = 0) const _NOEXCEPT;
1672
1673    _LIBCPP_INLINE_VISIBILITY
1674    size_type rfind(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
1675    size_type rfind(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1676    _LIBCPP_INLINE_VISIBILITY
1677    size_type rfind(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
1678    size_type rfind(value_type __c, size_type __pos = npos) const _NOEXCEPT;
1679
1680    _LIBCPP_INLINE_VISIBILITY
1681    size_type find_first_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
1682    size_type find_first_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1683    _LIBCPP_INLINE_VISIBILITY
1684    size_type find_first_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
1685    _LIBCPP_INLINE_VISIBILITY
1686    size_type find_first_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
1687
1688    _LIBCPP_INLINE_VISIBILITY
1689    size_type find_last_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
1690    size_type find_last_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1691    _LIBCPP_INLINE_VISIBILITY
1692    size_type find_last_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
1693    _LIBCPP_INLINE_VISIBILITY
1694    size_type find_last_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
1695
1696    _LIBCPP_INLINE_VISIBILITY
1697    size_type find_first_not_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
1698    size_type find_first_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1699    _LIBCPP_INLINE_VISIBILITY
1700    size_type find_first_not_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
1701    _LIBCPP_INLINE_VISIBILITY
1702    size_type find_first_not_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
1703
1704    _LIBCPP_INLINE_VISIBILITY
1705    size_type find_last_not_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
1706    size_type find_last_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1707    _LIBCPP_INLINE_VISIBILITY
1708    size_type find_last_not_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
1709    _LIBCPP_INLINE_VISIBILITY
1710    size_type find_last_not_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
1711
1712    _LIBCPP_INLINE_VISIBILITY
1713    int compare(const basic_string& __str) const _NOEXCEPT;
1714    _LIBCPP_INLINE_VISIBILITY
1715    int compare(size_type __pos1, size_type __n1, const basic_string& __str) const;
1716    int compare(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos) const;
1717    int compare(const value_type* __s) const _NOEXCEPT;
1718    int compare(size_type __pos1, size_type __n1, const value_type* __s) const;
1719    int compare(size_type __pos1, size_type __n1, const value_type* __s, size_type __n2) const;
1720
1721    _LIBCPP_INLINE_VISIBILITY bool __invariants() const;
1722
1723    _LIBCPP_INLINE_VISIBILITY
1724    bool __is_long() const _NOEXCEPT
1725        {return bool(__r_.first().__s.__size_ & __short_mask);}
1726
1727#if _LIBCPP_DEBUG_LEVEL >= 2
1728
1729    bool __dereferenceable(const const_iterator* __i) const;
1730    bool __decrementable(const const_iterator* __i) const;
1731    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
1732    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
1733
1734#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1735
1736private:
1737    _LIBCPP_INLINE_VISIBILITY
1738    allocator_type& __alloc() _NOEXCEPT
1739        {return __r_.second();}
1740    _LIBCPP_INLINE_VISIBILITY
1741    const allocator_type& __alloc() const _NOEXCEPT
1742        {return __r_.second();}
1743
1744#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1745
1746    _LIBCPP_INLINE_VISIBILITY
1747    void __set_short_size(size_type __s) _NOEXCEPT
1748#   if _LIBCPP_BIG_ENDIAN
1749        {__r_.first().__s.__size_ = (unsigned char)(__s << 1);}
1750#   else
1751        {__r_.first().__s.__size_ = (unsigned char)(__s);}
1752#   endif
1753
1754    _LIBCPP_INLINE_VISIBILITY
1755    size_type __get_short_size() const _NOEXCEPT
1756#   if _LIBCPP_BIG_ENDIAN
1757        {return __r_.first().__s.__size_ >> 1;}
1758#   else
1759        {return __r_.first().__s.__size_;}
1760#   endif
1761
1762#else  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1763
1764    _LIBCPP_INLINE_VISIBILITY
1765    void __set_short_size(size_type __s) _NOEXCEPT
1766#   if _LIBCPP_BIG_ENDIAN
1767        {__r_.first().__s.__size_ = (unsigned char)(__s);}
1768#   else
1769        {__r_.first().__s.__size_ = (unsigned char)(__s << 1);}
1770#   endif
1771
1772    _LIBCPP_INLINE_VISIBILITY
1773    size_type __get_short_size() const _NOEXCEPT
1774#   if _LIBCPP_BIG_ENDIAN
1775        {return __r_.first().__s.__size_;}
1776#   else
1777        {return __r_.first().__s.__size_ >> 1;}
1778#   endif
1779
1780#endif  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1781
1782    _LIBCPP_INLINE_VISIBILITY
1783    void __set_long_size(size_type __s) _NOEXCEPT
1784        {__r_.first().__l.__size_ = __s;}
1785    _LIBCPP_INLINE_VISIBILITY
1786    size_type __get_long_size() const _NOEXCEPT
1787        {return __r_.first().__l.__size_;}
1788    _LIBCPP_INLINE_VISIBILITY
1789    void __set_size(size_type __s) _NOEXCEPT
1790        {if (__is_long()) __set_long_size(__s); else __set_short_size(__s);}
1791
1792    _LIBCPP_INLINE_VISIBILITY
1793    void __set_long_cap(size_type __s) _NOEXCEPT
1794        {__r_.first().__l.__cap_  = __long_mask | __s;}
1795    _LIBCPP_INLINE_VISIBILITY
1796    size_type __get_long_cap() const _NOEXCEPT
1797        {return __r_.first().__l.__cap_ & size_type(~__long_mask);}
1798
1799    _LIBCPP_INLINE_VISIBILITY
1800    void __set_long_pointer(pointer __p) _NOEXCEPT
1801        {__r_.first().__l.__data_ = __p;}
1802    _LIBCPP_INLINE_VISIBILITY
1803    pointer __get_long_pointer() _NOEXCEPT
1804        {return __r_.first().__l.__data_;}
1805    _LIBCPP_INLINE_VISIBILITY
1806    const_pointer __get_long_pointer() const _NOEXCEPT
1807        {return __r_.first().__l.__data_;}
1808    _LIBCPP_INLINE_VISIBILITY
1809    pointer __get_short_pointer() _NOEXCEPT
1810        {return pointer_traits<pointer>::pointer_to(__r_.first().__s.__data_[0]);}
1811    _LIBCPP_INLINE_VISIBILITY
1812    const_pointer __get_short_pointer() const _NOEXCEPT
1813        {return pointer_traits<const_pointer>::pointer_to(__r_.first().__s.__data_[0]);}
1814    _LIBCPP_INLINE_VISIBILITY
1815    pointer __get_pointer() _NOEXCEPT
1816        {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
1817    _LIBCPP_INLINE_VISIBILITY
1818    const_pointer __get_pointer() const _NOEXCEPT
1819        {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
1820
1821    _LIBCPP_INLINE_VISIBILITY
1822    void __zero() _NOEXCEPT
1823        {
1824            size_type (&__a)[__n_words] = __r_.first().__r.__words;
1825            for (unsigned __i = 0; __i < __n_words; ++__i)
1826                __a[__i] = 0;
1827        }
1828
1829    template <size_type __a> static
1830        _LIBCPP_INLINE_VISIBILITY
1831        size_type __align_it(size_type __s) _NOEXCEPT
1832            {return (__s + (__a-1)) & ~(__a-1);}
1833    enum {__alignment = 16};
1834    static _LIBCPP_INLINE_VISIBILITY
1835    size_type __recommend(size_type __s) _NOEXCEPT
1836        {return (__s < __min_cap ? static_cast<size_type>(__min_cap) :
1837                 __align_it<sizeof(value_type) < __alignment ?
1838                            __alignment/sizeof(value_type) : 1 > (__s+1)) - 1;}
1839
1840    void __init(const value_type* __s, size_type __sz, size_type __reserve);
1841    void __init(const value_type* __s, size_type __sz);
1842    void __init(size_type __n, value_type __c);
1843
1844    template <class _InputIterator>
1845    typename enable_if
1846    <
1847        __is_exactly_input_iterator<_InputIterator>::value,
1848        void
1849    >::type
1850    __init(_InputIterator __first, _InputIterator __last);
1851
1852    template <class _ForwardIterator>
1853    typename enable_if
1854    <
1855        __is_forward_iterator<_ForwardIterator>::value,
1856        void
1857    >::type
1858    __init(_ForwardIterator __first, _ForwardIterator __last);
1859
1860    void __grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
1861                   size_type __n_copy,  size_type __n_del,     size_type __n_add = 0);
1862    void __grow_by_and_replace(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
1863                               size_type __n_copy,  size_type __n_del,
1864                               size_type __n_add, const value_type* __p_new_stuff);
1865
1866    _LIBCPP_INLINE_VISIBILITY
1867    void __erase_to_end(size_type __pos);
1868
1869    _LIBCPP_INLINE_VISIBILITY
1870    void __copy_assign_alloc(const basic_string& __str)
1871        {__copy_assign_alloc(__str, integral_constant<bool,
1872                      __alloc_traits::propagate_on_container_copy_assignment::value>());}
1873
1874    _LIBCPP_INLINE_VISIBILITY
1875    void __copy_assign_alloc(const basic_string& __str, true_type)
1876        {
1877            if (__alloc() != __str.__alloc())
1878            {
1879                clear();
1880                shrink_to_fit();
1881            }
1882            __alloc() = __str.__alloc();
1883        }
1884
1885    _LIBCPP_INLINE_VISIBILITY
1886    void __copy_assign_alloc(const basic_string&, false_type) _NOEXCEPT
1887        {}
1888
1889#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1890    _LIBCPP_INLINE_VISIBILITY
1891    void __move_assign(basic_string& __str, false_type)
1892        _NOEXCEPT_(__alloc_traits::is_always_equal::value);
1893    _LIBCPP_INLINE_VISIBILITY
1894    void __move_assign(basic_string& __str, true_type)
1895#if _LIBCPP_STD_VER > 14
1896        _NOEXCEPT;
1897#else
1898        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
1899#endif
1900#endif
1901
1902    _LIBCPP_INLINE_VISIBILITY
1903    void
1904    __move_assign_alloc(basic_string& __str)
1905        _NOEXCEPT_(
1906            !__alloc_traits::propagate_on_container_move_assignment::value ||
1907            is_nothrow_move_assignable<allocator_type>::value)
1908    {__move_assign_alloc(__str, integral_constant<bool,
1909                      __alloc_traits::propagate_on_container_move_assignment::value>());}
1910
1911    _LIBCPP_INLINE_VISIBILITY
1912    void __move_assign_alloc(basic_string& __c, true_type)
1913        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
1914        {
1915            __alloc() = _VSTD::move(__c.__alloc());
1916        }
1917
1918    _LIBCPP_INLINE_VISIBILITY
1919    void __move_assign_alloc(basic_string&, false_type)
1920        _NOEXCEPT
1921        {}
1922
1923    _LIBCPP_INLINE_VISIBILITY void __invalidate_all_iterators();
1924    _LIBCPP_INLINE_VISIBILITY void __invalidate_iterators_past(size_type);
1925
1926    friend basic_string operator+<>(const basic_string&, const basic_string&);
1927    friend basic_string operator+<>(const value_type*, const basic_string&);
1928    friend basic_string operator+<>(value_type, const basic_string&);
1929    friend basic_string operator+<>(const basic_string&, const value_type*);
1930    friend basic_string operator+<>(const basic_string&, value_type);
1931};
1932
1933template <class _CharT, class _Traits, class _Allocator>
1934inline _LIBCPP_INLINE_VISIBILITY
1935void
1936basic_string<_CharT, _Traits, _Allocator>::__invalidate_all_iterators()
1937{
1938#if _LIBCPP_DEBUG_LEVEL >= 2
1939    __get_db()->__invalidate_all(this);
1940#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1941}
1942
1943template <class _CharT, class _Traits, class _Allocator>
1944inline _LIBCPP_INLINE_VISIBILITY
1945void
1946basic_string<_CharT, _Traits, _Allocator>::__invalidate_iterators_past(size_type
1947#if _LIBCPP_DEBUG_LEVEL >= 2
1948                                                                        __pos
1949#endif
1950                                                                      )
1951{
1952#if _LIBCPP_DEBUG_LEVEL >= 2
1953    __c_node* __c = __get_db()->__find_c_and_lock(this);
1954    if (__c)
1955    {
1956        const_pointer __new_last = __get_pointer() + __pos;
1957        for (__i_node** __p = __c->end_; __p != __c->beg_; )
1958        {
1959            --__p;
1960            const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
1961            if (__i->base() > __new_last)
1962            {
1963                (*__p)->__c_ = nullptr;
1964                if (--__c->end_ != __p)
1965                    memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
1966            }
1967        }
1968        __get_db()->unlock();
1969    }
1970#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1971}
1972
1973template <class _CharT, class _Traits, class _Allocator>
1974inline _LIBCPP_INLINE_VISIBILITY
1975basic_string<_CharT, _Traits, _Allocator>::basic_string()
1976    _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
1977{
1978#if _LIBCPP_DEBUG_LEVEL >= 2
1979    __get_db()->__insert_c(this);
1980#endif
1981    __zero();
1982}
1983
1984template <class _CharT, class _Traits, class _Allocator>
1985inline _LIBCPP_INLINE_VISIBILITY
1986basic_string<_CharT, _Traits, _Allocator>::basic_string(const allocator_type& __a)
1987#if _LIBCPP_STD_VER <= 14
1988        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
1989#else
1990        _NOEXCEPT
1991#endif
1992: __r_(__a)
1993{
1994#if _LIBCPP_DEBUG_LEVEL >= 2
1995    __get_db()->__insert_c(this);
1996#endif
1997    __zero();
1998}
1999
2000template <class _CharT, class _Traits, class _Allocator>
2001void
2002basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz, size_type __reserve)
2003{
2004    if (__reserve > max_size())
2005        this->__throw_length_error();
2006    pointer __p;
2007    if (__reserve < __min_cap)
2008    {
2009        __set_short_size(__sz);
2010        __p = __get_short_pointer();
2011    }
2012    else
2013    {
2014        size_type __cap = __recommend(__reserve);
2015        __p = __alloc_traits::allocate(__alloc(), __cap+1);
2016        __set_long_pointer(__p);
2017        __set_long_cap(__cap+1);
2018        __set_long_size(__sz);
2019    }
2020    traits_type::copy(_VSTD::__to_raw_pointer(__p), __s, __sz);
2021    traits_type::assign(__p[__sz], value_type());
2022}
2023
2024template <class _CharT, class _Traits, class _Allocator>
2025void
2026basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz)
2027{
2028    if (__sz > max_size())
2029        this->__throw_length_error();
2030    pointer __p;
2031    if (__sz < __min_cap)
2032    {
2033        __set_short_size(__sz);
2034        __p = __get_short_pointer();
2035    }
2036    else
2037    {
2038        size_type __cap = __recommend(__sz);
2039        __p = __alloc_traits::allocate(__alloc(), __cap+1);
2040        __set_long_pointer(__p);
2041        __set_long_cap(__cap+1);
2042        __set_long_size(__sz);
2043    }
2044    traits_type::copy(_VSTD::__to_raw_pointer(__p), __s, __sz);
2045    traits_type::assign(__p[__sz], value_type());
2046}
2047
2048template <class _CharT, class _Traits, class _Allocator>
2049inline _LIBCPP_INLINE_VISIBILITY
2050basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s)
2051{
2052    _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*) detected nullptr");
2053    __init(__s, traits_type::length(__s));
2054#if _LIBCPP_DEBUG_LEVEL >= 2
2055    __get_db()->__insert_c(this);
2056#endif
2057}
2058
2059template <class _CharT, class _Traits, class _Allocator>
2060inline _LIBCPP_INLINE_VISIBILITY
2061basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s, const allocator_type& __a)
2062    : __r_(__a)
2063{
2064    _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*, allocator) detected nullptr");
2065    __init(__s, traits_type::length(__s));
2066#if _LIBCPP_DEBUG_LEVEL >= 2
2067    __get_db()->__insert_c(this);
2068#endif
2069}
2070
2071template <class _CharT, class _Traits, class _Allocator>
2072inline _LIBCPP_INLINE_VISIBILITY
2073basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s, size_type __n)
2074{
2075    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n) detected nullptr");
2076    __init(__s, __n);
2077#if _LIBCPP_DEBUG_LEVEL >= 2
2078    __get_db()->__insert_c(this);
2079#endif
2080}
2081
2082template <class _CharT, class _Traits, class _Allocator>
2083inline _LIBCPP_INLINE_VISIBILITY
2084basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s, size_type __n, const allocator_type& __a)
2085    : __r_(__a)
2086{
2087    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n, allocator) detected nullptr");
2088    __init(__s, __n);
2089#if _LIBCPP_DEBUG_LEVEL >= 2
2090    __get_db()->__insert_c(this);
2091#endif
2092}
2093
2094template <class _CharT, class _Traits, class _Allocator>
2095basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str)
2096    : __r_(__alloc_traits::select_on_container_copy_construction(__str.__alloc()))
2097{
2098    if (!__str.__is_long())
2099        __r_.first().__r = __str.__r_.first().__r;
2100    else
2101        __init(_VSTD::__to_raw_pointer(__str.__get_long_pointer()), __str.__get_long_size());
2102#if _LIBCPP_DEBUG_LEVEL >= 2
2103    __get_db()->__insert_c(this);
2104#endif
2105}
2106
2107template <class _CharT, class _Traits, class _Allocator>
2108basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str, const allocator_type& __a)
2109    : __r_(__a)
2110{
2111    if (!__str.__is_long())
2112        __r_.first().__r = __str.__r_.first().__r;
2113    else
2114        __init(_VSTD::__to_raw_pointer(__str.__get_long_pointer()), __str.__get_long_size());
2115#if _LIBCPP_DEBUG_LEVEL >= 2
2116    __get_db()->__insert_c(this);
2117#endif
2118}
2119
2120#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2121
2122template <class _CharT, class _Traits, class _Allocator>
2123inline _LIBCPP_INLINE_VISIBILITY
2124basic_string<_CharT, _Traits, _Allocator>::basic_string(basic_string&& __str)
2125#if _LIBCPP_STD_VER <= 14
2126        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
2127#else
2128        _NOEXCEPT
2129#endif
2130    : __r_(_VSTD::move(__str.__r_))
2131{
2132    __str.__zero();
2133#if _LIBCPP_DEBUG_LEVEL >= 2
2134    __get_db()->__insert_c(this);
2135    if (__is_long())
2136        __get_db()->swap(this, &__str);
2137#endif
2138}
2139
2140template <class _CharT, class _Traits, class _Allocator>
2141inline _LIBCPP_INLINE_VISIBILITY
2142basic_string<_CharT, _Traits, _Allocator>::basic_string(basic_string&& __str, const allocator_type& __a)
2143    : __r_(__a)
2144{
2145    if (__str.__is_long() && __a != __str.__alloc()) // copy, not move
2146        __init(_VSTD::__to_raw_pointer(__str.__get_long_pointer()), __str.__get_long_size());
2147    else
2148    {
2149        __r_.first().__r = __str.__r_.first().__r;
2150        __str.__zero();
2151    }
2152#if _LIBCPP_DEBUG_LEVEL >= 2
2153    __get_db()->__insert_c(this);
2154    if (__is_long())
2155        __get_db()->swap(this, &__str);
2156#endif
2157}
2158
2159#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
2160
2161template <class _CharT, class _Traits, class _Allocator>
2162void
2163basic_string<_CharT, _Traits, _Allocator>::__init(size_type __n, value_type __c)
2164{
2165    if (__n > max_size())
2166        this->__throw_length_error();
2167    pointer __p;
2168    if (__n < __min_cap)
2169    {
2170        __set_short_size(__n);
2171        __p = __get_short_pointer();
2172    }
2173    else
2174    {
2175        size_type __cap = __recommend(__n);
2176        __p = __alloc_traits::allocate(__alloc(), __cap+1);
2177        __set_long_pointer(__p);
2178        __set_long_cap(__cap+1);
2179        __set_long_size(__n);
2180    }
2181    traits_type::assign(_VSTD::__to_raw_pointer(__p), __n, __c);
2182    traits_type::assign(__p[__n], value_type());
2183}
2184
2185template <class _CharT, class _Traits, class _Allocator>
2186inline _LIBCPP_INLINE_VISIBILITY
2187basic_string<_CharT, _Traits, _Allocator>::basic_string(size_type __n, value_type __c)
2188{
2189    __init(__n, __c);
2190#if _LIBCPP_DEBUG_LEVEL >= 2
2191    __get_db()->__insert_c(this);
2192#endif
2193}
2194
2195template <class _CharT, class _Traits, class _Allocator>
2196inline _LIBCPP_INLINE_VISIBILITY
2197basic_string<_CharT, _Traits, _Allocator>::basic_string(size_type __n, value_type __c, const allocator_type& __a)
2198    : __r_(__a)
2199{
2200    __init(__n, __c);
2201#if _LIBCPP_DEBUG_LEVEL >= 2
2202    __get_db()->__insert_c(this);
2203#endif
2204}
2205
2206template <class _CharT, class _Traits, class _Allocator>
2207basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str, size_type __pos, size_type __n,
2208                                                        const allocator_type& __a)
2209    : __r_(__a)
2210{
2211    size_type __str_sz = __str.size();
2212    if (__pos > __str_sz)
2213        this->__throw_out_of_range();
2214    __init(__str.data() + __pos, _VSTD::min(__n, __str_sz - __pos));
2215#if _LIBCPP_DEBUG_LEVEL >= 2
2216    __get_db()->__insert_c(this);
2217#endif
2218}
2219
2220template <class _CharT, class _Traits, class _Allocator>
2221template <class _InputIterator>
2222typename enable_if
2223<
2224    __is_exactly_input_iterator<_InputIterator>::value,
2225    void
2226>::type
2227basic_string<_CharT, _Traits, _Allocator>::__init(_InputIterator __first, _InputIterator __last)
2228{
2229    __zero();
2230#ifndef _LIBCPP_NO_EXCEPTIONS
2231    try
2232    {
2233#endif  // _LIBCPP_NO_EXCEPTIONS
2234    for (; __first != __last; ++__first)
2235        push_back(*__first);
2236#ifndef _LIBCPP_NO_EXCEPTIONS
2237    }
2238    catch (...)
2239    {
2240        if (__is_long())
2241            __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
2242        throw;
2243    }
2244#endif  // _LIBCPP_NO_EXCEPTIONS
2245}
2246
2247template <class _CharT, class _Traits, class _Allocator>
2248template <class _ForwardIterator>
2249typename enable_if
2250<
2251    __is_forward_iterator<_ForwardIterator>::value,
2252    void
2253>::type
2254basic_string<_CharT, _Traits, _Allocator>::__init(_ForwardIterator __first, _ForwardIterator __last)
2255{
2256    size_type __sz = static_cast<size_type>(_VSTD::distance(__first, __last));
2257    if (__sz > max_size())
2258        this->__throw_length_error();
2259    pointer __p;
2260    if (__sz < __min_cap)
2261    {
2262        __set_short_size(__sz);
2263        __p = __get_short_pointer();
2264    }
2265    else
2266    {
2267        size_type __cap = __recommend(__sz);
2268        __p = __alloc_traits::allocate(__alloc(), __cap+1);
2269        __set_long_pointer(__p);
2270        __set_long_cap(__cap+1);
2271        __set_long_size(__sz);
2272    }
2273    for (; __first != __last; ++__first, (void) ++__p)
2274        traits_type::assign(*__p, *__first);
2275    traits_type::assign(*__p, value_type());
2276}
2277
2278template <class _CharT, class _Traits, class _Allocator>
2279template<class _InputIterator>
2280inline _LIBCPP_INLINE_VISIBILITY
2281basic_string<_CharT, _Traits, _Allocator>::basic_string(_InputIterator __first, _InputIterator __last)
2282{
2283    __init(__first, __last);
2284#if _LIBCPP_DEBUG_LEVEL >= 2
2285    __get_db()->__insert_c(this);
2286#endif
2287}
2288
2289template <class _CharT, class _Traits, class _Allocator>
2290template<class _InputIterator>
2291inline _LIBCPP_INLINE_VISIBILITY
2292basic_string<_CharT, _Traits, _Allocator>::basic_string(_InputIterator __first, _InputIterator __last,
2293                                                        const allocator_type& __a)
2294    : __r_(__a)
2295{
2296    __init(__first, __last);
2297#if _LIBCPP_DEBUG_LEVEL >= 2
2298    __get_db()->__insert_c(this);
2299#endif
2300}
2301
2302#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2303
2304template <class _CharT, class _Traits, class _Allocator>
2305inline _LIBCPP_INLINE_VISIBILITY
2306basic_string<_CharT, _Traits, _Allocator>::basic_string(initializer_list<value_type> __il)
2307{
2308    __init(__il.begin(), __il.end());
2309#if _LIBCPP_DEBUG_LEVEL >= 2
2310    __get_db()->__insert_c(this);
2311#endif
2312}
2313
2314template <class _CharT, class _Traits, class _Allocator>
2315inline _LIBCPP_INLINE_VISIBILITY
2316basic_string<_CharT, _Traits, _Allocator>::basic_string(initializer_list<value_type> __il, const allocator_type& __a)
2317    : __r_(__a)
2318{
2319    __init(__il.begin(), __il.end());
2320#if _LIBCPP_DEBUG_LEVEL >= 2
2321    __get_db()->__insert_c(this);
2322#endif
2323}
2324
2325#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2326
2327template <class _CharT, class _Traits, class _Allocator>
2328basic_string<_CharT, _Traits, _Allocator>::~basic_string()
2329{
2330#if _LIBCPP_DEBUG_LEVEL >= 2
2331    __get_db()->__erase_c(this);
2332#endif
2333    if (__is_long())
2334        __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
2335}
2336
2337template <class _CharT, class _Traits, class _Allocator>
2338void
2339basic_string<_CharT, _Traits, _Allocator>::__grow_by_and_replace
2340    (size_type __old_cap, size_type __delta_cap, size_type __old_sz,
2341     size_type __n_copy,  size_type __n_del,     size_type __n_add, const value_type* __p_new_stuff)
2342{
2343    size_type __ms = max_size();
2344    if (__delta_cap > __ms - __old_cap - 1)
2345        this->__throw_length_error();
2346    pointer __old_p = __get_pointer();
2347    size_type __cap = __old_cap < __ms / 2 - __alignment ?
2348                          __recommend(_VSTD::max(__old_cap + __delta_cap, 2 * __old_cap)) :
2349                          __ms - 1;
2350    pointer __p = __alloc_traits::allocate(__alloc(), __cap+1);
2351    __invalidate_all_iterators();
2352    if (__n_copy != 0)
2353        traits_type::copy(_VSTD::__to_raw_pointer(__p),
2354                          _VSTD::__to_raw_pointer(__old_p), __n_copy);
2355    if (__n_add != 0)
2356        traits_type::copy(_VSTD::__to_raw_pointer(__p) + __n_copy, __p_new_stuff, __n_add);
2357    size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
2358    if (__sec_cp_sz != 0)
2359        traits_type::copy(_VSTD::__to_raw_pointer(__p) + __n_copy + __n_add,
2360                          _VSTD::__to_raw_pointer(__old_p) + __n_copy + __n_del, __sec_cp_sz);
2361    if (__old_cap+1 != __min_cap)
2362        __alloc_traits::deallocate(__alloc(), __old_p, __old_cap+1);
2363    __set_long_pointer(__p);
2364    __set_long_cap(__cap+1);
2365    __old_sz = __n_copy + __n_add + __sec_cp_sz;
2366    __set_long_size(__old_sz);
2367    traits_type::assign(__p[__old_sz], value_type());
2368}
2369
2370template <class _CharT, class _Traits, class _Allocator>
2371void
2372basic_string<_CharT, _Traits, _Allocator>::__grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
2373                                                     size_type __n_copy,  size_type __n_del,     size_type __n_add)
2374{
2375    size_type __ms = max_size();
2376    if (__delta_cap > __ms - __old_cap)
2377        this->__throw_length_error();
2378    pointer __old_p = __get_pointer();
2379    size_type __cap = __old_cap < __ms / 2 - __alignment ?
2380                          __recommend(_VSTD::max(__old_cap + __delta_cap, 2 * __old_cap)) :
2381                          __ms - 1;
2382    pointer __p = __alloc_traits::allocate(__alloc(), __cap+1);
2383    __invalidate_all_iterators();
2384    if (__n_copy != 0)
2385        traits_type::copy(_VSTD::__to_raw_pointer(__p),
2386                          _VSTD::__to_raw_pointer(__old_p), __n_copy);
2387    size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
2388    if (__sec_cp_sz != 0)
2389        traits_type::copy(_VSTD::__to_raw_pointer(__p) + __n_copy + __n_add,
2390                          _VSTD::__to_raw_pointer(__old_p) + __n_copy + __n_del,
2391                          __sec_cp_sz);
2392    if (__old_cap+1 != __min_cap)
2393        __alloc_traits::deallocate(__alloc(), __old_p, __old_cap+1);
2394    __set_long_pointer(__p);
2395    __set_long_cap(__cap+1);
2396}
2397
2398// assign
2399
2400template <class _CharT, class _Traits, class _Allocator>
2401basic_string<_CharT, _Traits, _Allocator>&
2402basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s, size_type __n)
2403{
2404    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::assign received nullptr");
2405    size_type __cap = capacity();
2406    if (__cap >= __n)
2407    {
2408        value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2409        traits_type::move(__p, __s, __n);
2410        traits_type::assign(__p[__n], value_type());
2411        __set_size(__n);
2412        __invalidate_iterators_past(__n);
2413    }
2414    else
2415    {
2416        size_type __sz = size();
2417        __grow_by_and_replace(__cap, __n - __cap, __sz, 0, __sz, __n, __s);
2418    }
2419    return *this;
2420}
2421
2422template <class _CharT, class _Traits, class _Allocator>
2423basic_string<_CharT, _Traits, _Allocator>&
2424basic_string<_CharT, _Traits, _Allocator>::assign(size_type __n, value_type __c)
2425{
2426    size_type __cap = capacity();
2427    if (__cap < __n)
2428    {
2429        size_type __sz = size();
2430        __grow_by(__cap, __n - __cap, __sz, 0, __sz);
2431    }
2432    else
2433        __invalidate_iterators_past(__n);
2434    value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2435    traits_type::assign(__p, __n, __c);
2436    traits_type::assign(__p[__n], value_type());
2437    __set_size(__n);
2438    return *this;
2439}
2440
2441template <class _CharT, class _Traits, class _Allocator>
2442basic_string<_CharT, _Traits, _Allocator>&
2443basic_string<_CharT, _Traits, _Allocator>::operator=(value_type __c)
2444{
2445    pointer __p;
2446    if (__is_long())
2447    {
2448        __p = __get_long_pointer();
2449        __set_long_size(1);
2450    }
2451    else
2452    {
2453        __p = __get_short_pointer();
2454        __set_short_size(1);
2455    }
2456    traits_type::assign(*__p, __c);
2457    traits_type::assign(*++__p, value_type());
2458    __invalidate_iterators_past(1);
2459    return *this;
2460}
2461
2462template <class _CharT, class _Traits, class _Allocator>
2463basic_string<_CharT, _Traits, _Allocator>&
2464basic_string<_CharT, _Traits, _Allocator>::operator=(const basic_string& __str)
2465{
2466    if (this != &__str)
2467    {
2468        __copy_assign_alloc(__str);
2469        assign(__str);
2470    }
2471    return *this;
2472}
2473
2474#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2475
2476template <class _CharT, class _Traits, class _Allocator>
2477inline _LIBCPP_INLINE_VISIBILITY
2478void
2479basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, false_type)
2480    _NOEXCEPT_(__alloc_traits::is_always_equal::value)
2481{
2482    if (__alloc() != __str.__alloc())
2483        assign(__str);
2484    else
2485        __move_assign(__str, true_type());
2486}
2487
2488template <class _CharT, class _Traits, class _Allocator>
2489inline _LIBCPP_INLINE_VISIBILITY
2490void
2491basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, true_type)
2492#if _LIBCPP_STD_VER > 14
2493    _NOEXCEPT
2494#else
2495    _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
2496#endif
2497{
2498    clear();
2499    shrink_to_fit();
2500    __r_.first() = __str.__r_.first();
2501    __move_assign_alloc(__str);
2502    __str.__zero();
2503}
2504
2505template <class _CharT, class _Traits, class _Allocator>
2506inline _LIBCPP_INLINE_VISIBILITY
2507basic_string<_CharT, _Traits, _Allocator>&
2508basic_string<_CharT, _Traits, _Allocator>::operator=(basic_string&& __str)
2509    _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
2510{
2511    __move_assign(__str, integral_constant<bool,
2512          __alloc_traits::propagate_on_container_move_assignment::value>());
2513    return *this;
2514}
2515
2516#endif
2517
2518template <class _CharT, class _Traits, class _Allocator>
2519template<class _InputIterator>
2520typename enable_if
2521<
2522     __is_exactly_input_iterator <_InputIterator>::value
2523          || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
2524    basic_string<_CharT, _Traits, _Allocator>&
2525>::type
2526basic_string<_CharT, _Traits, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
2527{
2528    basic_string __temp(__first, __last, __alloc());
2529    assign(__temp.data(), __temp.size());
2530    return *this;
2531}
2532
2533template <class _CharT, class _Traits, class _Allocator>
2534template<class _ForwardIterator>
2535typename enable_if
2536<
2537    __is_forward_iterator<_ForwardIterator>::value
2538         && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
2539    basic_string<_CharT, _Traits, _Allocator>&
2540>::type
2541basic_string<_CharT, _Traits, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
2542{
2543    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
2544    size_type __cap = capacity();
2545    if (__cap < __n)
2546    {
2547        size_type __sz = size();
2548        __grow_by(__cap, __n - __cap, __sz, 0, __sz);
2549    }
2550    else
2551        __invalidate_iterators_past(__n);
2552    pointer __p = __get_pointer();
2553    for (; __first != __last; ++__first, ++__p)
2554        traits_type::assign(*__p, *__first);
2555    traits_type::assign(*__p, value_type());
2556    __set_size(__n);
2557    return *this;
2558}
2559
2560template <class _CharT, class _Traits, class _Allocator>
2561inline _LIBCPP_INLINE_VISIBILITY
2562basic_string<_CharT, _Traits, _Allocator>&
2563basic_string<_CharT, _Traits, _Allocator>::assign(const basic_string& __str)
2564{
2565    return assign(__str.data(), __str.size());
2566}
2567
2568template <class _CharT, class _Traits, class _Allocator>
2569basic_string<_CharT, _Traits, _Allocator>&
2570basic_string<_CharT, _Traits, _Allocator>::assign(const basic_string& __str, size_type __pos, size_type __n)
2571{
2572    size_type __sz = __str.size();
2573    if (__pos > __sz)
2574        this->__throw_out_of_range();
2575    return assign(__str.data() + __pos, _VSTD::min(__n, __sz - __pos));
2576}
2577
2578template <class _CharT, class _Traits, class _Allocator>
2579basic_string<_CharT, _Traits, _Allocator>&
2580basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s)
2581{
2582    _LIBCPP_ASSERT(__s != nullptr, "string::assign received nullptr");
2583    return assign(__s, traits_type::length(__s));
2584}
2585
2586// append
2587
2588template <class _CharT, class _Traits, class _Allocator>
2589basic_string<_CharT, _Traits, _Allocator>&
2590basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s, size_type __n)
2591{
2592    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::append received nullptr");
2593    size_type __cap = capacity();
2594    size_type __sz = size();
2595    if (__cap - __sz >= __n)
2596    {
2597        if (__n)
2598        {
2599            value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2600            traits_type::copy(__p + __sz, __s, __n);
2601            __sz += __n;
2602            __set_size(__sz);
2603            traits_type::assign(__p[__sz], value_type());
2604        }
2605    }
2606    else
2607        __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __sz, 0, __n, __s);
2608    return *this;
2609}
2610
2611template <class _CharT, class _Traits, class _Allocator>
2612basic_string<_CharT, _Traits, _Allocator>&
2613basic_string<_CharT, _Traits, _Allocator>::append(size_type __n, value_type __c)
2614{
2615    if (__n)
2616    {
2617        size_type __cap = capacity();
2618        size_type __sz = size();
2619        if (__cap - __sz < __n)
2620            __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
2621        pointer __p = __get_pointer();
2622        traits_type::assign(_VSTD::__to_raw_pointer(__p) + __sz, __n, __c);
2623        __sz += __n;
2624        __set_size(__sz);
2625        traits_type::assign(__p[__sz], value_type());
2626    }
2627    return *this;
2628}
2629
2630template <class _CharT, class _Traits, class _Allocator>
2631void
2632basic_string<_CharT, _Traits, _Allocator>::push_back(value_type __c)
2633{
2634    bool __is_short = !__is_long();
2635    size_type __cap;
2636    size_type __sz;
2637    if (__is_short)
2638    {
2639        __cap = __min_cap - 1;
2640        __sz = __get_short_size();
2641    }
2642    else
2643    {
2644        __cap = __get_long_cap() - 1;
2645        __sz = __get_long_size();
2646    }
2647    if (__sz == __cap)
2648    {
2649        __grow_by(__cap, 1, __sz, __sz, 0);
2650        __is_short = !__is_long();
2651    }
2652    pointer __p;
2653    if (__is_short)
2654    {
2655        __p = __get_short_pointer() + __sz;
2656        __set_short_size(__sz+1);
2657    }
2658    else
2659    {
2660        __p = __get_long_pointer() + __sz;
2661        __set_long_size(__sz+1);
2662    }
2663    traits_type::assign(*__p, __c);
2664    traits_type::assign(*++__p, value_type());
2665}
2666
2667template <class _CharT, class _Traits, class _Allocator>
2668template<class _InputIterator>
2669typename enable_if
2670<
2671    __is_exactly_input_iterator<_InputIterator>::value
2672             || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
2673    basic_string<_CharT, _Traits, _Allocator>&
2674>::type
2675basic_string<_CharT, _Traits, _Allocator>::append(_InputIterator __first, _InputIterator __last)
2676{
2677	basic_string __temp (__first, __last, __alloc());
2678	append(__temp.data(), __temp.size());
2679    return *this;
2680}
2681
2682template <class _CharT, class _Traits, class _Allocator>
2683template<class _ForwardIterator>
2684typename enable_if
2685<
2686    __is_forward_iterator<_ForwardIterator>::value
2687          && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
2688    basic_string<_CharT, _Traits, _Allocator>&
2689>::type
2690basic_string<_CharT, _Traits, _Allocator>::append(_ForwardIterator __first, _ForwardIterator __last)
2691{
2692    size_type __sz = size();
2693    size_type __cap = capacity();
2694    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
2695    if (__n)
2696    {
2697        if (__cap - __sz < __n)
2698            __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
2699        pointer __p = __get_pointer() + __sz;
2700        for (; __first != __last; ++__p, ++__first)
2701            traits_type::assign(*__p, *__first);
2702        traits_type::assign(*__p, value_type());
2703        __set_size(__sz + __n);
2704    }
2705    return *this;
2706}
2707
2708template <class _CharT, class _Traits, class _Allocator>
2709inline _LIBCPP_INLINE_VISIBILITY
2710basic_string<_CharT, _Traits, _Allocator>&
2711basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str)
2712{
2713    return append(__str.data(), __str.size());
2714}
2715
2716template <class _CharT, class _Traits, class _Allocator>
2717basic_string<_CharT, _Traits, _Allocator>&
2718basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str, size_type __pos, size_type __n)
2719{
2720    size_type __sz = __str.size();
2721    if (__pos > __sz)
2722        this->__throw_out_of_range();
2723    return append(__str.data() + __pos, _VSTD::min(__n, __sz - __pos));
2724}
2725
2726template <class _CharT, class _Traits, class _Allocator>
2727basic_string<_CharT, _Traits, _Allocator>&
2728basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s)
2729{
2730    _LIBCPP_ASSERT(__s != nullptr, "string::append received nullptr");
2731    return append(__s, traits_type::length(__s));
2732}
2733
2734// insert
2735
2736template <class _CharT, class _Traits, class _Allocator>
2737basic_string<_CharT, _Traits, _Allocator>&
2738basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s, size_type __n)
2739{
2740    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::insert received nullptr");
2741    size_type __sz = size();
2742    if (__pos > __sz)
2743        this->__throw_out_of_range();
2744    size_type __cap = capacity();
2745    if (__cap - __sz >= __n)
2746    {
2747        if (__n)
2748        {
2749            value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2750            size_type __n_move = __sz - __pos;
2751            if (__n_move != 0)
2752            {
2753                if (__p + __pos <= __s && __s < __p + __sz)
2754                    __s += __n;
2755                traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
2756            }
2757            traits_type::move(__p + __pos, __s, __n);
2758            __sz += __n;
2759            __set_size(__sz);
2760            traits_type::assign(__p[__sz], value_type());
2761        }
2762    }
2763    else
2764        __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __pos, 0, __n, __s);
2765    return *this;
2766}
2767
2768template <class _CharT, class _Traits, class _Allocator>
2769basic_string<_CharT, _Traits, _Allocator>&
2770basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, size_type __n, value_type __c)
2771{
2772    size_type __sz = size();
2773    if (__pos > __sz)
2774        this->__throw_out_of_range();
2775    if (__n)
2776    {
2777        size_type __cap = capacity();
2778        value_type* __p;
2779        if (__cap - __sz >= __n)
2780        {
2781            __p = _VSTD::__to_raw_pointer(__get_pointer());
2782            size_type __n_move = __sz - __pos;
2783            if (__n_move != 0)
2784                traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
2785        }
2786        else
2787        {
2788            __grow_by(__cap, __sz + __n - __cap, __sz, __pos, 0, __n);
2789            __p = _VSTD::__to_raw_pointer(__get_long_pointer());
2790        }
2791        traits_type::assign(__p + __pos, __n, __c);
2792        __sz += __n;
2793        __set_size(__sz);
2794        traits_type::assign(__p[__sz], value_type());
2795    }
2796    return *this;
2797}
2798
2799template <class _CharT, class _Traits, class _Allocator>
2800template<class _InputIterator>
2801typename enable_if
2802<
2803   __is_exactly_input_iterator<_InputIterator>::value
2804        || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
2805   typename basic_string<_CharT, _Traits, _Allocator>::iterator
2806>::type
2807basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _InputIterator __first, _InputIterator __last)
2808{
2809#if _LIBCPP_DEBUG_LEVEL >= 2
2810    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
2811        "string::insert(iterator, range) called with an iterator not"
2812        " referring to this string");
2813#endif
2814    basic_string __temp(__first, __last, __alloc());
2815    return insert(__pos, __temp.data(), __temp.data() + __temp.size());
2816}
2817
2818template <class _CharT, class _Traits, class _Allocator>
2819template<class _ForwardIterator>
2820typename enable_if
2821<
2822    __is_forward_iterator<_ForwardIterator>::value
2823        && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
2824    typename basic_string<_CharT, _Traits, _Allocator>::iterator
2825>::type
2826basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last)
2827{
2828#if _LIBCPP_DEBUG_LEVEL >= 2
2829    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
2830        "string::insert(iterator, range) called with an iterator not"
2831        " referring to this string");
2832#endif
2833    size_type __ip = static_cast<size_type>(__pos - begin());
2834    size_type __sz = size();
2835    size_type __cap = capacity();
2836    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
2837    if (__n)
2838    {
2839        value_type* __p;
2840        if (__cap - __sz >= __n)
2841        {
2842            __p = _VSTD::__to_raw_pointer(__get_pointer());
2843            size_type __n_move = __sz - __ip;
2844            if (__n_move != 0)
2845                traits_type::move(__p + __ip + __n, __p + __ip, __n_move);
2846        }
2847        else
2848        {
2849            __grow_by(__cap, __sz + __n - __cap, __sz, __ip, 0, __n);
2850            __p = _VSTD::__to_raw_pointer(__get_long_pointer());
2851        }
2852        __sz += __n;
2853        __set_size(__sz);
2854        traits_type::assign(__p[__sz], value_type());
2855        for (__p += __ip; __first != __last; ++__p, ++__first)
2856            traits_type::assign(*__p, *__first);
2857    }
2858    return begin() + __ip;
2859}
2860
2861template <class _CharT, class _Traits, class _Allocator>
2862inline _LIBCPP_INLINE_VISIBILITY
2863basic_string<_CharT, _Traits, _Allocator>&
2864basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str)
2865{
2866    return insert(__pos1, __str.data(), __str.size());
2867}
2868
2869template <class _CharT, class _Traits, class _Allocator>
2870basic_string<_CharT, _Traits, _Allocator>&
2871basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str,
2872                                                  size_type __pos2, size_type __n)
2873{
2874    size_type __str_sz = __str.size();
2875    if (__pos2 > __str_sz)
2876        this->__throw_out_of_range();
2877    return insert(__pos1, __str.data() + __pos2, _VSTD::min(__n, __str_sz - __pos2));
2878}
2879
2880template <class _CharT, class _Traits, class _Allocator>
2881basic_string<_CharT, _Traits, _Allocator>&
2882basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s)
2883{
2884    _LIBCPP_ASSERT(__s != nullptr, "string::insert received nullptr");
2885    return insert(__pos, __s, traits_type::length(__s));
2886}
2887
2888template <class _CharT, class _Traits, class _Allocator>
2889typename basic_string<_CharT, _Traits, _Allocator>::iterator
2890basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, value_type __c)
2891{
2892    size_type __ip = static_cast<size_type>(__pos - begin());
2893    size_type __sz = size();
2894    size_type __cap = capacity();
2895    value_type* __p;
2896    if (__cap == __sz)
2897    {
2898        __grow_by(__cap, 1, __sz, __ip, 0, 1);
2899        __p = _VSTD::__to_raw_pointer(__get_long_pointer());
2900    }
2901    else
2902    {
2903        __p = _VSTD::__to_raw_pointer(__get_pointer());
2904        size_type __n_move = __sz - __ip;
2905        if (__n_move != 0)
2906            traits_type::move(__p + __ip + 1, __p + __ip, __n_move);
2907    }
2908    traits_type::assign(__p[__ip], __c);
2909    traits_type::assign(__p[++__sz], value_type());
2910    __set_size(__sz);
2911    return begin() + static_cast<difference_type>(__ip);
2912}
2913
2914template <class _CharT, class _Traits, class _Allocator>
2915inline _LIBCPP_INLINE_VISIBILITY
2916typename basic_string<_CharT, _Traits, _Allocator>::iterator
2917basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, size_type __n, value_type __c)
2918{
2919#if _LIBCPP_DEBUG_LEVEL >= 2
2920    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
2921        "string::insert(iterator, n, value) called with an iterator not"
2922        " referring to this string");
2923#endif
2924    difference_type __p = __pos - begin();
2925    insert(static_cast<size_type>(__p), __n, __c);
2926    return begin() + __p;
2927}
2928
2929// replace
2930
2931template <class _CharT, class _Traits, class _Allocator>
2932basic_string<_CharT, _Traits, _Allocator>&
2933basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2)
2934{
2935    _LIBCPP_ASSERT(__n2 == 0 || __s != nullptr, "string::replace received nullptr");
2936    size_type __sz = size();
2937    if (__pos > __sz)
2938        this->__throw_out_of_range();
2939    __n1 = _VSTD::min(__n1, __sz - __pos);
2940    size_type __cap = capacity();
2941    if (__cap - __sz + __n1 >= __n2)
2942    {
2943        value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2944        if (__n1 != __n2)
2945        {
2946            size_type __n_move = __sz - __pos - __n1;
2947            if (__n_move != 0)
2948            {
2949                if (__n1 > __n2)
2950                {
2951                    traits_type::move(__p + __pos, __s, __n2);
2952                    traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
2953                    goto __finish;
2954                }
2955                if (__p + __pos < __s && __s < __p + __sz)
2956                {
2957                    if (__p + __pos + __n1 <= __s)
2958                        __s += __n2 - __n1;
2959                    else // __p + __pos < __s < __p + __pos + __n1
2960                    {
2961                        traits_type::move(__p + __pos, __s, __n1);
2962                        __pos += __n1;
2963                        __s += __n2;
2964                        __n2 -= __n1;
2965                        __n1 = 0;
2966                    }
2967                }
2968                traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
2969            }
2970        }
2971        traits_type::move(__p + __pos, __s, __n2);
2972__finish:
2973        __sz += __n2 - __n1;
2974        __set_size(__sz);
2975        __invalidate_iterators_past(__sz);
2976        traits_type::assign(__p[__sz], value_type());
2977    }
2978    else
2979        __grow_by_and_replace(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2, __s);
2980    return *this;
2981}
2982
2983template <class _CharT, class _Traits, class _Allocator>
2984basic_string<_CharT, _Traits, _Allocator>&
2985basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, size_type __n2, value_type __c)
2986{
2987    size_type __sz = size();
2988    if (__pos > __sz)
2989        this->__throw_out_of_range();
2990    __n1 = _VSTD::min(__n1, __sz - __pos);
2991    size_type __cap = capacity();
2992    value_type* __p;
2993    if (__cap - __sz + __n1 >= __n2)
2994    {
2995        __p = _VSTD::__to_raw_pointer(__get_pointer());
2996        if (__n1 != __n2)
2997        {
2998            size_type __n_move = __sz - __pos - __n1;
2999            if (__n_move != 0)
3000                traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
3001        }
3002    }
3003    else
3004    {
3005        __grow_by(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2);
3006        __p = _VSTD::__to_raw_pointer(__get_long_pointer());
3007    }
3008    traits_type::assign(__p + __pos, __n2, __c);
3009    __sz += __n2 - __n1;
3010    __set_size(__sz);
3011    __invalidate_iterators_past(__sz);
3012    traits_type::assign(__p[__sz], value_type());
3013    return *this;
3014}
3015
3016template <class _CharT, class _Traits, class _Allocator>
3017template<class _InputIterator>
3018typename enable_if
3019<
3020    __is_input_iterator<_InputIterator>::value,
3021    basic_string<_CharT, _Traits, _Allocator>&
3022>::type
3023basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2,
3024                                                   _InputIterator __j1, _InputIterator __j2)
3025{
3026    basic_string __temp(__j1, __j2, __alloc());
3027    return this->replace(__i1, __i2, __temp);
3028}
3029
3030template <class _CharT, class _Traits, class _Allocator>
3031inline _LIBCPP_INLINE_VISIBILITY
3032basic_string<_CharT, _Traits, _Allocator>&
3033basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const basic_string& __str)
3034{
3035    return replace(__pos1, __n1, __str.data(), __str.size());
3036}
3037
3038template <class _CharT, class _Traits, class _Allocator>
3039basic_string<_CharT, _Traits, _Allocator>&
3040basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const basic_string& __str,
3041                                                   size_type __pos2, size_type __n2)
3042{
3043    size_type __str_sz = __str.size();
3044    if (__pos2 > __str_sz)
3045        this->__throw_out_of_range();
3046    return replace(__pos1, __n1, __str.data() + __pos2, _VSTD::min(__n2, __str_sz - __pos2));
3047}
3048
3049template <class _CharT, class _Traits, class _Allocator>
3050basic_string<_CharT, _Traits, _Allocator>&
3051basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s)
3052{
3053    _LIBCPP_ASSERT(__s != nullptr, "string::replace received nullptr");
3054    return replace(__pos, __n1, __s, traits_type::length(__s));
3055}
3056
3057template <class _CharT, class _Traits, class _Allocator>
3058inline _LIBCPP_INLINE_VISIBILITY
3059basic_string<_CharT, _Traits, _Allocator>&
3060basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const basic_string& __str)
3061{
3062    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1),
3063                   __str.data(), __str.size());
3064}
3065
3066template <class _CharT, class _Traits, class _Allocator>
3067inline _LIBCPP_INLINE_VISIBILITY
3068basic_string<_CharT, _Traits, _Allocator>&
3069basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const value_type* __s, size_type __n)
3070{
3071    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s, __n);
3072}
3073
3074template <class _CharT, class _Traits, class _Allocator>
3075inline _LIBCPP_INLINE_VISIBILITY
3076basic_string<_CharT, _Traits, _Allocator>&
3077basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const value_type* __s)
3078{
3079    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s);
3080}
3081
3082template <class _CharT, class _Traits, class _Allocator>
3083inline _LIBCPP_INLINE_VISIBILITY
3084basic_string<_CharT, _Traits, _Allocator>&
3085basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c)
3086{
3087    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __n, __c);
3088}
3089
3090// erase
3091
3092template <class _CharT, class _Traits, class _Allocator>
3093basic_string<_CharT, _Traits, _Allocator>&
3094basic_string<_CharT, _Traits, _Allocator>::erase(size_type __pos, size_type __n)
3095{
3096    size_type __sz = size();
3097    if (__pos > __sz)
3098        this->__throw_out_of_range();
3099    if (__n)
3100    {
3101        value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
3102        __n = _VSTD::min(__n, __sz - __pos);
3103        size_type __n_move = __sz - __pos - __n;
3104        if (__n_move != 0)
3105            traits_type::move(__p + __pos, __p + __pos + __n, __n_move);
3106        __sz -= __n;
3107        __set_size(__sz);
3108        __invalidate_iterators_past(__sz);
3109        traits_type::assign(__p[__sz], value_type());
3110    }
3111    return *this;
3112}
3113
3114template <class _CharT, class _Traits, class _Allocator>
3115inline _LIBCPP_INLINE_VISIBILITY
3116typename basic_string<_CharT, _Traits, _Allocator>::iterator
3117basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __pos)
3118{
3119#if _LIBCPP_DEBUG_LEVEL >= 2
3120    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
3121        "string::erase(iterator) called with an iterator not"
3122        " referring to this string");
3123#endif
3124    _LIBCPP_ASSERT(__pos != end(),
3125        "string::erase(iterator) called with a non-dereferenceable iterator");
3126    iterator __b = begin();
3127    size_type __r = static_cast<size_type>(__pos - __b);
3128    erase(__r, 1);
3129    return __b + static_cast<difference_type>(__r);
3130}
3131
3132template <class _CharT, class _Traits, class _Allocator>
3133inline _LIBCPP_INLINE_VISIBILITY
3134typename basic_string<_CharT, _Traits, _Allocator>::iterator
3135basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __first, const_iterator __last)
3136{
3137#if _LIBCPP_DEBUG_LEVEL >= 2
3138    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
3139        "string::erase(iterator,  iterator) called with an iterator not"
3140        " referring to this string");
3141#endif
3142    _LIBCPP_ASSERT(__first <= __last, "string::erase(first, last) called with invalid range");
3143    iterator __b = begin();
3144    size_type __r = static_cast<size_type>(__first - __b);
3145    erase(__r, static_cast<size_type>(__last - __first));
3146    return __b + static_cast<difference_type>(__r);
3147}
3148
3149template <class _CharT, class _Traits, class _Allocator>
3150inline _LIBCPP_INLINE_VISIBILITY
3151void
3152basic_string<_CharT, _Traits, _Allocator>::pop_back()
3153{
3154    _LIBCPP_ASSERT(!empty(), "string::pop_back(): string is already empty");
3155    size_type __sz;
3156    if (__is_long())
3157    {
3158        __sz = __get_long_size() - 1;
3159        __set_long_size(__sz);
3160        traits_type::assign(*(__get_long_pointer() + __sz), value_type());
3161    }
3162    else
3163    {
3164        __sz = __get_short_size() - 1;
3165        __set_short_size(__sz);
3166        traits_type::assign(*(__get_short_pointer() + __sz), value_type());
3167    }
3168    __invalidate_iterators_past(__sz);
3169}
3170
3171template <class _CharT, class _Traits, class _Allocator>
3172inline _LIBCPP_INLINE_VISIBILITY
3173void
3174basic_string<_CharT, _Traits, _Allocator>::clear() _NOEXCEPT
3175{
3176    __invalidate_all_iterators();
3177    if (__is_long())
3178    {
3179        traits_type::assign(*__get_long_pointer(), value_type());
3180        __set_long_size(0);
3181    }
3182    else
3183    {
3184        traits_type::assign(*__get_short_pointer(), value_type());
3185        __set_short_size(0);
3186    }
3187}
3188
3189template <class _CharT, class _Traits, class _Allocator>
3190inline _LIBCPP_INLINE_VISIBILITY
3191void
3192basic_string<_CharT, _Traits, _Allocator>::__erase_to_end(size_type __pos)
3193{
3194    if (__is_long())
3195    {
3196        traits_type::assign(*(__get_long_pointer() + __pos), value_type());
3197        __set_long_size(__pos);
3198    }
3199    else
3200    {
3201        traits_type::assign(*(__get_short_pointer() + __pos), value_type());
3202        __set_short_size(__pos);
3203    }
3204    __invalidate_iterators_past(__pos);
3205}
3206
3207template <class _CharT, class _Traits, class _Allocator>
3208void
3209basic_string<_CharT, _Traits, _Allocator>::resize(size_type __n, value_type __c)
3210{
3211    size_type __sz = size();
3212    if (__n > __sz)
3213        append(__n - __sz, __c);
3214    else
3215        __erase_to_end(__n);
3216}
3217
3218template <class _CharT, class _Traits, class _Allocator>
3219inline _LIBCPP_INLINE_VISIBILITY
3220typename basic_string<_CharT, _Traits, _Allocator>::size_type
3221basic_string<_CharT, _Traits, _Allocator>::max_size() const _NOEXCEPT
3222{
3223    size_type __m = __alloc_traits::max_size(__alloc());
3224#if _LIBCPP_BIG_ENDIAN
3225    return (__m <= ~__long_mask ? __m : __m/2) - __alignment;
3226#else
3227    return __m - __alignment;
3228#endif
3229}
3230
3231template <class _CharT, class _Traits, class _Allocator>
3232void
3233basic_string<_CharT, _Traits, _Allocator>::reserve(size_type __res_arg)
3234{
3235    if (__res_arg > max_size())
3236        this->__throw_length_error();
3237    size_type __cap = capacity();
3238    size_type __sz = size();
3239    __res_arg = _VSTD::max(__res_arg, __sz);
3240    __res_arg = __recommend(__res_arg);
3241    if (__res_arg != __cap)
3242    {
3243        pointer __new_data, __p;
3244        bool __was_long, __now_long;
3245        if (__res_arg == __min_cap - 1)
3246        {
3247            __was_long = true;
3248            __now_long = false;
3249            __new_data = __get_short_pointer();
3250            __p = __get_long_pointer();
3251        }
3252        else
3253        {
3254            if (__res_arg > __cap)
3255                __new_data = __alloc_traits::allocate(__alloc(), __res_arg+1);
3256            else
3257            {
3258            #ifndef _LIBCPP_NO_EXCEPTIONS
3259                try
3260                {
3261            #endif  // _LIBCPP_NO_EXCEPTIONS
3262                    __new_data = __alloc_traits::allocate(__alloc(), __res_arg+1);
3263            #ifndef _LIBCPP_NO_EXCEPTIONS
3264                }
3265                catch (...)
3266                {
3267                    return;
3268                }
3269            #else  // _LIBCPP_NO_EXCEPTIONS
3270                if (__new_data == nullptr)
3271                    return;
3272            #endif  // _LIBCPP_NO_EXCEPTIONS
3273            }
3274            __now_long = true;
3275            __was_long = __is_long();
3276            __p = __get_pointer();
3277        }
3278        traits_type::copy(_VSTD::__to_raw_pointer(__new_data),
3279                          _VSTD::__to_raw_pointer(__p), size()+1);
3280        if (__was_long)
3281            __alloc_traits::deallocate(__alloc(), __p, __cap+1);
3282        if (__now_long)
3283        {
3284            __set_long_cap(__res_arg+1);
3285            __set_long_size(__sz);
3286            __set_long_pointer(__new_data);
3287        }
3288        else
3289            __set_short_size(__sz);
3290        __invalidate_all_iterators();
3291    }
3292}
3293
3294template <class _CharT, class _Traits, class _Allocator>
3295inline _LIBCPP_INLINE_VISIBILITY
3296typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3297basic_string<_CharT, _Traits, _Allocator>::operator[](size_type __pos) const
3298{
3299    _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
3300    return *(data() + __pos);
3301}
3302
3303template <class _CharT, class _Traits, class _Allocator>
3304inline _LIBCPP_INLINE_VISIBILITY
3305typename basic_string<_CharT, _Traits, _Allocator>::reference
3306basic_string<_CharT, _Traits, _Allocator>::operator[](size_type __pos)
3307{
3308    _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
3309    return *(__get_pointer() + __pos);
3310}
3311
3312template <class _CharT, class _Traits, class _Allocator>
3313typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3314basic_string<_CharT, _Traits, _Allocator>::at(size_type __n) const
3315{
3316    if (__n >= size())
3317        this->__throw_out_of_range();
3318    return (*this)[__n];
3319}
3320
3321template <class _CharT, class _Traits, class _Allocator>
3322typename basic_string<_CharT, _Traits, _Allocator>::reference
3323basic_string<_CharT, _Traits, _Allocator>::at(size_type __n)
3324{
3325    if (__n >= size())
3326        this->__throw_out_of_range();
3327    return (*this)[__n];
3328}
3329
3330template <class _CharT, class _Traits, class _Allocator>
3331inline _LIBCPP_INLINE_VISIBILITY
3332typename basic_string<_CharT, _Traits, _Allocator>::reference
3333basic_string<_CharT, _Traits, _Allocator>::front()
3334{
3335    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
3336    return *__get_pointer();
3337}
3338
3339template <class _CharT, class _Traits, class _Allocator>
3340inline _LIBCPP_INLINE_VISIBILITY
3341typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3342basic_string<_CharT, _Traits, _Allocator>::front() const
3343{
3344    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
3345    return *data();
3346}
3347
3348template <class _CharT, class _Traits, class _Allocator>
3349inline _LIBCPP_INLINE_VISIBILITY
3350typename basic_string<_CharT, _Traits, _Allocator>::reference
3351basic_string<_CharT, _Traits, _Allocator>::back()
3352{
3353    _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
3354    return *(__get_pointer() + size() - 1);
3355}
3356
3357template <class _CharT, class _Traits, class _Allocator>
3358inline _LIBCPP_INLINE_VISIBILITY
3359typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3360basic_string<_CharT, _Traits, _Allocator>::back() const
3361{
3362    _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
3363    return *(data() + size() - 1);
3364}
3365
3366template <class _CharT, class _Traits, class _Allocator>
3367typename basic_string<_CharT, _Traits, _Allocator>::size_type
3368basic_string<_CharT, _Traits, _Allocator>::copy(value_type* __s, size_type __n, size_type __pos) const
3369{
3370    size_type __sz = size();
3371    if (__pos > __sz)
3372        this->__throw_out_of_range();
3373    size_type __rlen = _VSTD::min(__n, __sz - __pos);
3374    traits_type::copy(__s, data() + __pos, __rlen);
3375    return __rlen;
3376}
3377
3378template <class _CharT, class _Traits, class _Allocator>
3379inline _LIBCPP_INLINE_VISIBILITY
3380basic_string<_CharT, _Traits, _Allocator>
3381basic_string<_CharT, _Traits, _Allocator>::substr(size_type __pos, size_type __n) const
3382{
3383    return basic_string(*this, __pos, __n, __alloc());
3384}
3385
3386template <class _CharT, class _Traits, class _Allocator>
3387inline _LIBCPP_INLINE_VISIBILITY
3388void
3389basic_string<_CharT, _Traits, _Allocator>::swap(basic_string& __str)
3390#if _LIBCPP_STD_VER >= 14
3391        _NOEXCEPT
3392#else
3393        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
3394                    __is_nothrow_swappable<allocator_type>::value)
3395#endif
3396{
3397#if _LIBCPP_DEBUG_LEVEL >= 2
3398    if (!__is_long())
3399        __get_db()->__invalidate_all(this);
3400    if (!__str.__is_long())
3401        __get_db()->__invalidate_all(&__str);
3402    __get_db()->swap(this, &__str);
3403#endif
3404    _VSTD::swap(__r_.first(), __str.__r_.first());
3405    __swap_allocator(__alloc(), __str.__alloc());
3406}
3407
3408// find
3409
3410template <class _Traits>
3411struct _LIBCPP_HIDDEN __traits_eq
3412{
3413    typedef typename _Traits::char_type char_type;
3414    _LIBCPP_INLINE_VISIBILITY
3415    bool operator()(const char_type& __x, const char_type& __y) _NOEXCEPT
3416        {return _Traits::eq(__x, __y);}
3417};
3418
3419template<class _CharT, class _Traits, class _Allocator>
3420typename basic_string<_CharT, _Traits, _Allocator>::size_type
3421basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
3422                                                size_type __pos,
3423                                                size_type __n) const _NOEXCEPT
3424{
3425    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find(): received nullptr");
3426    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3427        (data(), size(), __s, __pos, __n);
3428}
3429
3430template<class _CharT, class _Traits, class _Allocator>
3431inline _LIBCPP_INLINE_VISIBILITY
3432typename basic_string<_CharT, _Traits, _Allocator>::size_type
3433basic_string<_CharT, _Traits, _Allocator>::find(const basic_string& __str,
3434                                                size_type __pos) const _NOEXCEPT
3435{
3436    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3437        (data(), size(), __str.data(), __pos, __str.size());
3438}
3439
3440template<class _CharT, class _Traits, class _Allocator>
3441inline _LIBCPP_INLINE_VISIBILITY
3442typename basic_string<_CharT, _Traits, _Allocator>::size_type
3443basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
3444                                                size_type __pos) const _NOEXCEPT
3445{
3446    _LIBCPP_ASSERT(__s != nullptr, "string::find(): received nullptr");
3447    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3448        (data(), size(), __s, __pos, traits_type::length(__s));
3449}
3450
3451template<class _CharT, class _Traits, class _Allocator>
3452typename basic_string<_CharT, _Traits, _Allocator>::size_type
3453basic_string<_CharT, _Traits, _Allocator>::find(value_type __c,
3454                                                size_type __pos) const _NOEXCEPT
3455{
3456    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3457        (data(), size(), __c, __pos);
3458}
3459
3460// rfind
3461
3462template<class _CharT, class _Traits, class _Allocator>
3463typename basic_string<_CharT, _Traits, _Allocator>::size_type
3464basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
3465                                                 size_type __pos,
3466                                                 size_type __n) const _NOEXCEPT
3467{
3468    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::rfind(): received nullptr");
3469    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3470        (data(), size(), __s, __pos, __n);
3471}
3472
3473template<class _CharT, class _Traits, class _Allocator>
3474inline _LIBCPP_INLINE_VISIBILITY
3475typename basic_string<_CharT, _Traits, _Allocator>::size_type
3476basic_string<_CharT, _Traits, _Allocator>::rfind(const basic_string& __str,
3477                                                 size_type __pos) const _NOEXCEPT
3478{
3479    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3480        (data(), size(), __str.data(), __pos, __str.size());
3481}
3482
3483template<class _CharT, class _Traits, class _Allocator>
3484inline _LIBCPP_INLINE_VISIBILITY
3485typename basic_string<_CharT, _Traits, _Allocator>::size_type
3486basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
3487                                                 size_type __pos) const _NOEXCEPT
3488{
3489    _LIBCPP_ASSERT(__s != nullptr, "string::rfind(): received nullptr");
3490    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3491        (data(), size(), __s, __pos, traits_type::length(__s));
3492}
3493
3494template<class _CharT, class _Traits, class _Allocator>
3495typename basic_string<_CharT, _Traits, _Allocator>::size_type
3496basic_string<_CharT, _Traits, _Allocator>::rfind(value_type __c,
3497                                                 size_type __pos) const _NOEXCEPT
3498{
3499    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3500        (data(), size(), __c, __pos);
3501}
3502
3503// find_first_of
3504
3505template<class _CharT, class _Traits, class _Allocator>
3506typename basic_string<_CharT, _Traits, _Allocator>::size_type
3507basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
3508                                                         size_type __pos,
3509                                                         size_type __n) const _NOEXCEPT
3510{
3511    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_first_of(): received nullptr");
3512    return _VSTD::__str_find_first_of<value_type, size_type, traits_type, npos>
3513        (data(), size(), __s, __pos, __n);
3514}
3515
3516template<class _CharT, class _Traits, class _Allocator>
3517inline _LIBCPP_INLINE_VISIBILITY
3518typename basic_string<_CharT, _Traits, _Allocator>::size_type
3519basic_string<_CharT, _Traits, _Allocator>::find_first_of(const basic_string& __str,
3520                                                         size_type __pos) const _NOEXCEPT
3521{
3522    return _VSTD::__str_find_first_of<value_type, size_type, traits_type, npos>
3523        (data(), size(), __str.data(), __pos, __str.size());
3524}
3525
3526template<class _CharT, class _Traits, class _Allocator>
3527inline _LIBCPP_INLINE_VISIBILITY
3528typename basic_string<_CharT, _Traits, _Allocator>::size_type
3529basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
3530                                                         size_type __pos) const _NOEXCEPT
3531{
3532    _LIBCPP_ASSERT(__s != nullptr, "string::find_first_of(): received nullptr");
3533    return _VSTD::__str_find_first_of<value_type, size_type, traits_type, npos>
3534        (data(), size(), __s, __pos, traits_type::length(__s));
3535}
3536
3537template<class _CharT, class _Traits, class _Allocator>
3538inline _LIBCPP_INLINE_VISIBILITY
3539typename basic_string<_CharT, _Traits, _Allocator>::size_type
3540basic_string<_CharT, _Traits, _Allocator>::find_first_of(value_type __c,
3541                                                         size_type __pos) const _NOEXCEPT
3542{
3543    return find(__c, __pos);
3544}
3545
3546// find_last_of
3547
3548template<class _CharT, class _Traits, class _Allocator>
3549typename basic_string<_CharT, _Traits, _Allocator>::size_type
3550basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
3551                                                        size_type __pos,
3552                                                        size_type __n) const _NOEXCEPT
3553{
3554    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_last_of(): received nullptr");
3555    return _VSTD::__str_find_last_of<value_type, size_type, traits_type, npos>
3556        (data(), size(), __s, __pos, __n);
3557}
3558
3559template<class _CharT, class _Traits, class _Allocator>
3560inline _LIBCPP_INLINE_VISIBILITY
3561typename basic_string<_CharT, _Traits, _Allocator>::size_type
3562basic_string<_CharT, _Traits, _Allocator>::find_last_of(const basic_string& __str,
3563                                                        size_type __pos) const _NOEXCEPT
3564{
3565    return _VSTD::__str_find_last_of<value_type, size_type, traits_type, npos>
3566        (data(), size(), __str.data(), __pos, __str.size());
3567}
3568
3569template<class _CharT, class _Traits, class _Allocator>
3570inline _LIBCPP_INLINE_VISIBILITY
3571typename basic_string<_CharT, _Traits, _Allocator>::size_type
3572basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
3573                                                        size_type __pos) const _NOEXCEPT
3574{
3575    _LIBCPP_ASSERT(__s != nullptr, "string::find_last_of(): received nullptr");
3576    return _VSTD::__str_find_last_of<value_type, size_type, traits_type, npos>
3577        (data(), size(), __s, __pos, traits_type::length(__s));
3578}
3579
3580template<class _CharT, class _Traits, class _Allocator>
3581inline _LIBCPP_INLINE_VISIBILITY
3582typename basic_string<_CharT, _Traits, _Allocator>::size_type
3583basic_string<_CharT, _Traits, _Allocator>::find_last_of(value_type __c,
3584                                                        size_type __pos) const _NOEXCEPT
3585{
3586    return rfind(__c, __pos);
3587}
3588
3589// find_first_not_of
3590
3591template<class _CharT, class _Traits, class _Allocator>
3592typename basic_string<_CharT, _Traits, _Allocator>::size_type
3593basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
3594                                                             size_type __pos,
3595                                                             size_type __n) const _NOEXCEPT
3596{
3597    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_first_not_of(): received nullptr");
3598    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3599        (data(), size(), __s, __pos, __n);
3600}
3601
3602template<class _CharT, class _Traits, class _Allocator>
3603inline _LIBCPP_INLINE_VISIBILITY
3604typename basic_string<_CharT, _Traits, _Allocator>::size_type
3605basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const basic_string& __str,
3606                                                             size_type __pos) const _NOEXCEPT
3607{
3608    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3609        (data(), size(), __str.data(), __pos, __str.size());
3610}
3611
3612template<class _CharT, class _Traits, class _Allocator>
3613inline _LIBCPP_INLINE_VISIBILITY
3614typename basic_string<_CharT, _Traits, _Allocator>::size_type
3615basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
3616                                                             size_type __pos) const _NOEXCEPT
3617{
3618    _LIBCPP_ASSERT(__s != nullptr, "string::find_first_not_of(): received nullptr");
3619    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3620        (data(), size(), __s, __pos, traits_type::length(__s));
3621}
3622
3623template<class _CharT, class _Traits, class _Allocator>
3624inline _LIBCPP_INLINE_VISIBILITY
3625typename basic_string<_CharT, _Traits, _Allocator>::size_type
3626basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(value_type __c,
3627                                                             size_type __pos) const _NOEXCEPT
3628{
3629    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3630        (data(), size(), __c, __pos);
3631}
3632
3633// find_last_not_of
3634
3635template<class _CharT, class _Traits, class _Allocator>
3636typename basic_string<_CharT, _Traits, _Allocator>::size_type
3637basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
3638                                                            size_type __pos,
3639                                                            size_type __n) const _NOEXCEPT
3640{
3641    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_last_not_of(): received nullptr");
3642    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3643        (data(), size(), __s, __pos, __n);
3644}
3645
3646template<class _CharT, class _Traits, class _Allocator>
3647inline _LIBCPP_INLINE_VISIBILITY
3648typename basic_string<_CharT, _Traits, _Allocator>::size_type
3649basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const basic_string& __str,
3650                                                            size_type __pos) const _NOEXCEPT
3651{
3652    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3653        (data(), size(), __str.data(), __pos, __str.size());
3654}
3655
3656template<class _CharT, class _Traits, class _Allocator>
3657inline _LIBCPP_INLINE_VISIBILITY
3658typename basic_string<_CharT, _Traits, _Allocator>::size_type
3659basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
3660                                                            size_type __pos) const _NOEXCEPT
3661{
3662    _LIBCPP_ASSERT(__s != nullptr, "string::find_last_not_of(): received nullptr");
3663    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3664        (data(), size(), __s, __pos, traits_type::length(__s));
3665}
3666
3667template<class _CharT, class _Traits, class _Allocator>
3668inline _LIBCPP_INLINE_VISIBILITY
3669typename basic_string<_CharT, _Traits, _Allocator>::size_type
3670basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(value_type __c,
3671                                                            size_type __pos) const _NOEXCEPT
3672{
3673    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3674        (data(), size(), __c, __pos);
3675}
3676
3677// compare
3678
3679template <class _CharT, class _Traits, class _Allocator>
3680inline _LIBCPP_INLINE_VISIBILITY
3681int
3682basic_string<_CharT, _Traits, _Allocator>::compare(const basic_string& __str) const _NOEXCEPT
3683{
3684    size_t __lhs_sz = size();
3685    size_t __rhs_sz = __str.size();
3686    int __result = traits_type::compare(data(), __str.data(),
3687                                        _VSTD::min(__lhs_sz, __rhs_sz));
3688    if (__result != 0)
3689        return __result;
3690    if (__lhs_sz < __rhs_sz)
3691        return -1;
3692    if (__lhs_sz > __rhs_sz)
3693        return 1;
3694    return 0;
3695}
3696
3697template <class _CharT, class _Traits, class _Allocator>
3698inline _LIBCPP_INLINE_VISIBILITY
3699int
3700basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3701                                                   size_type __n1,
3702                                                   const basic_string& __str) const
3703{
3704    return compare(__pos1, __n1, __str.data(), __str.size());
3705}
3706
3707template <class _CharT, class _Traits, class _Allocator>
3708int
3709basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3710                                                   size_type __n1,
3711                                                   const basic_string& __str,
3712                                                   size_type __pos2,
3713                                                   size_type __n2) const
3714{
3715    size_type __sz = __str.size();
3716    if (__pos2 > __sz)
3717        this->__throw_out_of_range();
3718    return compare(__pos1, __n1, __str.data() + __pos2, _VSTD::min(__n2,
3719                                                                  __sz - __pos2));
3720}
3721
3722template <class _CharT, class _Traits, class _Allocator>
3723int
3724basic_string<_CharT, _Traits, _Allocator>::compare(const value_type* __s) const _NOEXCEPT
3725{
3726    _LIBCPP_ASSERT(__s != nullptr, "string::compare(): received nullptr");
3727    return compare(0, npos, __s, traits_type::length(__s));
3728}
3729
3730template <class _CharT, class _Traits, class _Allocator>
3731int
3732basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3733                                                   size_type __n1,
3734                                                   const value_type* __s) const
3735{
3736    _LIBCPP_ASSERT(__s != nullptr, "string::compare(): received nullptr");
3737    return compare(__pos1, __n1, __s, traits_type::length(__s));
3738}
3739
3740template <class _CharT, class _Traits, class _Allocator>
3741int
3742basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3743                                                   size_type __n1,
3744                                                   const value_type* __s,
3745                                                   size_type __n2) const
3746{
3747    _LIBCPP_ASSERT(__n2 == 0 || __s != nullptr, "string::compare(): received nullptr");
3748    size_type __sz = size();
3749    if (__pos1 > __sz || __n2 == npos)
3750        this->__throw_out_of_range();
3751    size_type __rlen = _VSTD::min(__n1, __sz - __pos1);
3752    int __r = traits_type::compare(data() + __pos1, __s, _VSTD::min(__rlen, __n2));
3753    if (__r == 0)
3754    {
3755        if (__rlen < __n2)
3756            __r = -1;
3757        else if (__rlen > __n2)
3758            __r = 1;
3759    }
3760    return __r;
3761}
3762
3763// __invariants
3764
3765template<class _CharT, class _Traits, class _Allocator>
3766inline _LIBCPP_INLINE_VISIBILITY
3767bool
3768basic_string<_CharT, _Traits, _Allocator>::__invariants() const
3769{
3770    if (size() > capacity())
3771        return false;
3772    if (capacity() < __min_cap - 1)
3773        return false;
3774    if (data() == 0)
3775        return false;
3776    if (data()[size()] != value_type(0))
3777        return false;
3778    return true;
3779}
3780
3781// operator==
3782
3783template<class _CharT, class _Traits, class _Allocator>
3784inline _LIBCPP_INLINE_VISIBILITY
3785bool
3786operator==(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3787           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3788{
3789    size_t __lhs_sz = __lhs.size();
3790    return __lhs_sz == __rhs.size() && _Traits::compare(__lhs.data(),
3791                                                        __rhs.data(),
3792                                                        __lhs_sz) == 0;
3793}
3794
3795template<class _Allocator>
3796inline _LIBCPP_INLINE_VISIBILITY
3797bool
3798operator==(const basic_string<char, char_traits<char>, _Allocator>& __lhs,
3799           const basic_string<char, char_traits<char>, _Allocator>& __rhs) _NOEXCEPT
3800{
3801    size_t __lhs_sz = __lhs.size();
3802    if (__lhs_sz != __rhs.size())
3803        return false;
3804    const char* __lp = __lhs.data();
3805    const char* __rp = __rhs.data();
3806    if (__lhs.__is_long())
3807        return char_traits<char>::compare(__lp, __rp, __lhs_sz) == 0;
3808    for (; __lhs_sz != 0; --__lhs_sz, ++__lp, ++__rp)
3809        if (*__lp != *__rp)
3810            return false;
3811    return true;
3812}
3813
3814template<class _CharT, class _Traits, class _Allocator>
3815inline _LIBCPP_INLINE_VISIBILITY
3816bool
3817operator==(const _CharT* __lhs,
3818           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3819{
3820    typedef basic_string<_CharT, _Traits, _Allocator> _String;
3821    _LIBCPP_ASSERT(__lhs != nullptr, "operator==(char*, basic_string): received nullptr");
3822    size_t __lhs_len = _Traits::length(__lhs);
3823    if (__lhs_len != __rhs.size()) return false;
3824    return __rhs.compare(0, _String::npos, __lhs, __lhs_len) == 0;
3825}
3826
3827template<class _CharT, class _Traits, class _Allocator>
3828inline _LIBCPP_INLINE_VISIBILITY
3829bool
3830operator==(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
3831           const _CharT* __rhs) _NOEXCEPT
3832{
3833    typedef basic_string<_CharT, _Traits, _Allocator> _String;
3834    _LIBCPP_ASSERT(__rhs != nullptr, "operator==(basic_string, char*): received nullptr");
3835    size_t __rhs_len = _Traits::length(__rhs);
3836    if (__rhs_len != __lhs.size()) return false;
3837    return __lhs.compare(0, _String::npos, __rhs, __rhs_len) == 0;
3838}
3839
3840// operator!=
3841
3842template<class _CharT, class _Traits, class _Allocator>
3843inline _LIBCPP_INLINE_VISIBILITY
3844bool
3845operator!=(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
3846           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3847{
3848    return !(__lhs == __rhs);
3849}
3850
3851template<class _CharT, class _Traits, class _Allocator>
3852inline _LIBCPP_INLINE_VISIBILITY
3853bool
3854operator!=(const _CharT* __lhs,
3855           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3856{
3857    return !(__lhs == __rhs);
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 == __rhs);
3867}
3868
3869// operator<
3870
3871template<class _CharT, class _Traits, class _Allocator>
3872inline _LIBCPP_INLINE_VISIBILITY
3873bool
3874operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3875           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3876{
3877    return __lhs.compare(__rhs) < 0;
3878}
3879
3880template<class _CharT, class _Traits, class _Allocator>
3881inline _LIBCPP_INLINE_VISIBILITY
3882bool
3883operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3884           const _CharT* __rhs) _NOEXCEPT
3885{
3886    return __lhs.compare(__rhs) < 0;
3887}
3888
3889template<class _CharT, class _Traits, class _Allocator>
3890inline _LIBCPP_INLINE_VISIBILITY
3891bool
3892operator< (const _CharT* __lhs,
3893           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3894{
3895    return __rhs.compare(__lhs) > 0;
3896}
3897
3898// operator>
3899
3900template<class _CharT, class _Traits, class _Allocator>
3901inline _LIBCPP_INLINE_VISIBILITY
3902bool
3903operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3904           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3905{
3906    return __rhs < __lhs;
3907}
3908
3909template<class _CharT, class _Traits, class _Allocator>
3910inline _LIBCPP_INLINE_VISIBILITY
3911bool
3912operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3913           const _CharT* __rhs) _NOEXCEPT
3914{
3915    return __rhs < __lhs;
3916}
3917
3918template<class _CharT, class _Traits, class _Allocator>
3919inline _LIBCPP_INLINE_VISIBILITY
3920bool
3921operator> (const _CharT* __lhs,
3922           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3923{
3924    return __rhs < __lhs;
3925}
3926
3927// operator<=
3928
3929template<class _CharT, class _Traits, class _Allocator>
3930inline _LIBCPP_INLINE_VISIBILITY
3931bool
3932operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3933           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3934{
3935    return !(__rhs < __lhs);
3936}
3937
3938template<class _CharT, class _Traits, class _Allocator>
3939inline _LIBCPP_INLINE_VISIBILITY
3940bool
3941operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3942           const _CharT* __rhs) _NOEXCEPT
3943{
3944    return !(__rhs < __lhs);
3945}
3946
3947template<class _CharT, class _Traits, class _Allocator>
3948inline _LIBCPP_INLINE_VISIBILITY
3949bool
3950operator<=(const _CharT* __lhs,
3951           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3952{
3953    return !(__rhs < __lhs);
3954}
3955
3956// operator>=
3957
3958template<class _CharT, class _Traits, class _Allocator>
3959inline _LIBCPP_INLINE_VISIBILITY
3960bool
3961operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3962           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3963{
3964    return !(__lhs < __rhs);
3965}
3966
3967template<class _CharT, class _Traits, class _Allocator>
3968inline _LIBCPP_INLINE_VISIBILITY
3969bool
3970operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3971           const _CharT* __rhs) _NOEXCEPT
3972{
3973    return !(__lhs < __rhs);
3974}
3975
3976template<class _CharT, class _Traits, class _Allocator>
3977inline _LIBCPP_INLINE_VISIBILITY
3978bool
3979operator>=(const _CharT* __lhs,
3980           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3981{
3982    return !(__lhs < __rhs);
3983}
3984
3985// operator +
3986
3987template<class _CharT, class _Traits, class _Allocator>
3988basic_string<_CharT, _Traits, _Allocator>
3989operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3990          const basic_string<_CharT, _Traits, _Allocator>& __rhs)
3991{
3992    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
3993    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
3994    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
3995    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + __rhs_sz);
3996    __r.append(__rhs.data(), __rhs_sz);
3997    return __r;
3998}
3999
4000template<class _CharT, class _Traits, class _Allocator>
4001basic_string<_CharT, _Traits, _Allocator>
4002operator+(const _CharT* __lhs , const basic_string<_CharT,_Traits,_Allocator>& __rhs)
4003{
4004    basic_string<_CharT, _Traits, _Allocator> __r(__rhs.get_allocator());
4005    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = _Traits::length(__lhs);
4006    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
4007    __r.__init(__lhs, __lhs_sz, __lhs_sz + __rhs_sz);
4008    __r.append(__rhs.data(), __rhs_sz);
4009    return __r;
4010}
4011
4012template<class _CharT, class _Traits, class _Allocator>
4013basic_string<_CharT, _Traits, _Allocator>
4014operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Allocator>& __rhs)
4015{
4016    basic_string<_CharT, _Traits, _Allocator> __r(__rhs.get_allocator());
4017    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
4018    __r.__init(&__lhs, 1, 1 + __rhs_sz);
4019    __r.append(__rhs.data(), __rhs_sz);
4020    return __r;
4021}
4022
4023template<class _CharT, class _Traits, class _Allocator>
4024basic_string<_CharT, _Traits, _Allocator>
4025operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs)
4026{
4027    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
4028    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
4029    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = _Traits::length(__rhs);
4030    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + __rhs_sz);
4031    __r.append(__rhs, __rhs_sz);
4032    return __r;
4033}
4034
4035template<class _CharT, class _Traits, class _Allocator>
4036basic_string<_CharT, _Traits, _Allocator>
4037operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, _CharT __rhs)
4038{
4039    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
4040    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
4041    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + 1);
4042    __r.push_back(__rhs);
4043    return __r;
4044}
4045
4046#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
4047
4048template<class _CharT, class _Traits, class _Allocator>
4049inline _LIBCPP_INLINE_VISIBILITY
4050basic_string<_CharT, _Traits, _Allocator>
4051operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const basic_string<_CharT, _Traits, _Allocator>& __rhs)
4052{
4053    return _VSTD::move(__lhs.append(__rhs));
4054}
4055
4056template<class _CharT, class _Traits, class _Allocator>
4057inline _LIBCPP_INLINE_VISIBILITY
4058basic_string<_CharT, _Traits, _Allocator>
4059operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
4060{
4061    return _VSTD::move(__rhs.insert(0, __lhs));
4062}
4063
4064template<class _CharT, class _Traits, class _Allocator>
4065inline _LIBCPP_INLINE_VISIBILITY
4066basic_string<_CharT, _Traits, _Allocator>
4067operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
4068{
4069    return _VSTD::move(__lhs.append(__rhs));
4070}
4071
4072template<class _CharT, class _Traits, class _Allocator>
4073inline _LIBCPP_INLINE_VISIBILITY
4074basic_string<_CharT, _Traits, _Allocator>
4075operator+(const _CharT* __lhs , basic_string<_CharT,_Traits,_Allocator>&& __rhs)
4076{
4077    return _VSTD::move(__rhs.insert(0, __lhs));
4078}
4079
4080template<class _CharT, class _Traits, class _Allocator>
4081inline _LIBCPP_INLINE_VISIBILITY
4082basic_string<_CharT, _Traits, _Allocator>
4083operator+(_CharT __lhs, basic_string<_CharT,_Traits,_Allocator>&& __rhs)
4084{
4085    __rhs.insert(__rhs.begin(), __lhs);
4086    return _VSTD::move(__rhs);
4087}
4088
4089template<class _CharT, class _Traits, class _Allocator>
4090inline _LIBCPP_INLINE_VISIBILITY
4091basic_string<_CharT, _Traits, _Allocator>
4092operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const _CharT* __rhs)
4093{
4094    return _VSTD::move(__lhs.append(__rhs));
4095}
4096
4097template<class _CharT, class _Traits, class _Allocator>
4098inline _LIBCPP_INLINE_VISIBILITY
4099basic_string<_CharT, _Traits, _Allocator>
4100operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, _CharT __rhs)
4101{
4102    __lhs.push_back(__rhs);
4103    return _VSTD::move(__lhs);
4104}
4105
4106#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
4107
4108// swap
4109
4110template<class _CharT, class _Traits, class _Allocator>
4111inline _LIBCPP_INLINE_VISIBILITY
4112void
4113swap(basic_string<_CharT, _Traits, _Allocator>& __lhs,
4114     basic_string<_CharT, _Traits, _Allocator>& __rhs)
4115     _NOEXCEPT_(_NOEXCEPT_(__lhs.swap(__rhs)))
4116{
4117    __lhs.swap(__rhs);
4118}
4119
4120#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
4121
4122typedef basic_string<char16_t> u16string;
4123typedef basic_string<char32_t> u32string;
4124
4125#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
4126
4127_LIBCPP_FUNC_VIS int                stoi  (const string& __str, size_t* __idx = 0, int __base = 10);
4128_LIBCPP_FUNC_VIS long               stol  (const string& __str, size_t* __idx = 0, int __base = 10);
4129_LIBCPP_FUNC_VIS unsigned long      stoul (const string& __str, size_t* __idx = 0, int __base = 10);
4130_LIBCPP_FUNC_VIS long long          stoll (const string& __str, size_t* __idx = 0, int __base = 10);
4131_LIBCPP_FUNC_VIS unsigned long long stoull(const string& __str, size_t* __idx = 0, int __base = 10);
4132
4133_LIBCPP_FUNC_VIS float       stof (const string& __str, size_t* __idx = 0);
4134_LIBCPP_FUNC_VIS double      stod (const string& __str, size_t* __idx = 0);
4135_LIBCPP_FUNC_VIS long double stold(const string& __str, size_t* __idx = 0);
4136
4137_LIBCPP_FUNC_VIS string to_string(int __val);
4138_LIBCPP_FUNC_VIS string to_string(unsigned __val);
4139_LIBCPP_FUNC_VIS string to_string(long __val);
4140_LIBCPP_FUNC_VIS string to_string(unsigned long __val);
4141_LIBCPP_FUNC_VIS string to_string(long long __val);
4142_LIBCPP_FUNC_VIS string to_string(unsigned long long __val);
4143_LIBCPP_FUNC_VIS string to_string(float __val);
4144_LIBCPP_FUNC_VIS string to_string(double __val);
4145_LIBCPP_FUNC_VIS string to_string(long double __val);
4146
4147_LIBCPP_FUNC_VIS int                stoi  (const wstring& __str, size_t* __idx = 0, int __base = 10);
4148_LIBCPP_FUNC_VIS long               stol  (const wstring& __str, size_t* __idx = 0, int __base = 10);
4149_LIBCPP_FUNC_VIS unsigned long      stoul (const wstring& __str, size_t* __idx = 0, int __base = 10);
4150_LIBCPP_FUNC_VIS long long          stoll (const wstring& __str, size_t* __idx = 0, int __base = 10);
4151_LIBCPP_FUNC_VIS unsigned long long stoull(const wstring& __str, size_t* __idx = 0, int __base = 10);
4152
4153_LIBCPP_FUNC_VIS float       stof (const wstring& __str, size_t* __idx = 0);
4154_LIBCPP_FUNC_VIS double      stod (const wstring& __str, size_t* __idx = 0);
4155_LIBCPP_FUNC_VIS long double stold(const wstring& __str, size_t* __idx = 0);
4156
4157_LIBCPP_FUNC_VIS wstring to_wstring(int __val);
4158_LIBCPP_FUNC_VIS wstring to_wstring(unsigned __val);
4159_LIBCPP_FUNC_VIS wstring to_wstring(long __val);
4160_LIBCPP_FUNC_VIS wstring to_wstring(unsigned long __val);
4161_LIBCPP_FUNC_VIS wstring to_wstring(long long __val);
4162_LIBCPP_FUNC_VIS wstring to_wstring(unsigned long long __val);
4163_LIBCPP_FUNC_VIS wstring to_wstring(float __val);
4164_LIBCPP_FUNC_VIS wstring to_wstring(double __val);
4165_LIBCPP_FUNC_VIS wstring to_wstring(long double __val);
4166
4167template<class _CharT, class _Traits, class _Allocator>
4168    const typename basic_string<_CharT, _Traits, _Allocator>::size_type
4169                   basic_string<_CharT, _Traits, _Allocator>::npos;
4170
4171template<class _CharT, class _Traits, class _Allocator>
4172struct _LIBCPP_TYPE_VIS_ONLY hash<basic_string<_CharT, _Traits, _Allocator> >
4173    : public unary_function<basic_string<_CharT, _Traits, _Allocator>, size_t>
4174{
4175    size_t
4176        operator()(const basic_string<_CharT, _Traits, _Allocator>& __val) const _NOEXCEPT;
4177};
4178
4179template<class _CharT, class _Traits, class _Allocator>
4180size_t
4181hash<basic_string<_CharT, _Traits, _Allocator> >::operator()(
4182        const basic_string<_CharT, _Traits, _Allocator>& __val) const _NOEXCEPT
4183{
4184    return __do_string_hash(__val.data(), __val.data() + __val.size());
4185}
4186
4187template<class _CharT, class _Traits, class _Allocator>
4188basic_ostream<_CharT, _Traits>&
4189operator<<(basic_ostream<_CharT, _Traits>& __os,
4190           const basic_string<_CharT, _Traits, _Allocator>& __str);
4191
4192template<class _CharT, class _Traits, class _Allocator>
4193basic_istream<_CharT, _Traits>&
4194operator>>(basic_istream<_CharT, _Traits>& __is,
4195           basic_string<_CharT, _Traits, _Allocator>& __str);
4196
4197template<class _CharT, class _Traits, class _Allocator>
4198basic_istream<_CharT, _Traits>&
4199getline(basic_istream<_CharT, _Traits>& __is,
4200        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
4201
4202template<class _CharT, class _Traits, class _Allocator>
4203inline _LIBCPP_INLINE_VISIBILITY
4204basic_istream<_CharT, _Traits>&
4205getline(basic_istream<_CharT, _Traits>& __is,
4206        basic_string<_CharT, _Traits, _Allocator>& __str);
4207
4208#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
4209
4210template<class _CharT, class _Traits, class _Allocator>
4211inline _LIBCPP_INLINE_VISIBILITY
4212basic_istream<_CharT, _Traits>&
4213getline(basic_istream<_CharT, _Traits>&& __is,
4214        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
4215
4216template<class _CharT, class _Traits, class _Allocator>
4217inline _LIBCPP_INLINE_VISIBILITY
4218basic_istream<_CharT, _Traits>&
4219getline(basic_istream<_CharT, _Traits>&& __is,
4220        basic_string<_CharT, _Traits, _Allocator>& __str);
4221
4222#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
4223
4224#if _LIBCPP_DEBUG_LEVEL >= 2
4225
4226template<class _CharT, class _Traits, class _Allocator>
4227bool
4228basic_string<_CharT, _Traits, _Allocator>::__dereferenceable(const const_iterator* __i) const
4229{
4230    return this->data() <= _VSTD::__to_raw_pointer(__i->base()) &&
4231           _VSTD::__to_raw_pointer(__i->base()) < this->data() + this->size();
4232}
4233
4234template<class _CharT, class _Traits, class _Allocator>
4235bool
4236basic_string<_CharT, _Traits, _Allocator>::__decrementable(const const_iterator* __i) const
4237{
4238    return this->data() < _VSTD::__to_raw_pointer(__i->base()) &&
4239           _VSTD::__to_raw_pointer(__i->base()) <= this->data() + this->size();
4240}
4241
4242template<class _CharT, class _Traits, class _Allocator>
4243bool
4244basic_string<_CharT, _Traits, _Allocator>::__addable(const const_iterator* __i, ptrdiff_t __n) const
4245{
4246    const value_type* __p = _VSTD::__to_raw_pointer(__i->base()) + __n;
4247    return this->data() <= __p && __p <= this->data() + this->size();
4248}
4249
4250template<class _CharT, class _Traits, class _Allocator>
4251bool
4252basic_string<_CharT, _Traits, _Allocator>::__subscriptable(const const_iterator* __i, ptrdiff_t __n) const
4253{
4254    const value_type* __p = _VSTD::__to_raw_pointer(__i->base()) + __n;
4255    return this->data() <= __p && __p < this->data() + this->size();
4256}
4257
4258#endif  // _LIBCPP_DEBUG_LEVEL >= 2
4259
4260#if _LIBCPP_STD_VER > 11
4261// Literal suffixes for basic_string [basic.string.literals]
4262inline namespace literals
4263{
4264  inline namespace string_literals
4265  {
4266    inline _LIBCPP_INLINE_VISIBILITY
4267    basic_string<char> operator "" s( const char *__str, size_t __len )
4268    {
4269        return basic_string<char> (__str, __len);
4270    }
4271
4272    inline _LIBCPP_INLINE_VISIBILITY
4273    basic_string<wchar_t> operator "" s( const wchar_t *__str, size_t __len )
4274    {
4275        return basic_string<wchar_t> (__str, __len);
4276    }
4277
4278    inline _LIBCPP_INLINE_VISIBILITY
4279    basic_string<char16_t> operator "" s( const char16_t *__str, size_t __len )
4280    {
4281        return basic_string<char16_t> (__str, __len);
4282    }
4283
4284    inline _LIBCPP_INLINE_VISIBILITY
4285    basic_string<char32_t> operator "" s( const char32_t *__str, size_t __len )
4286    {
4287        return basic_string<char32_t> (__str, __len);
4288    }
4289  }
4290}
4291#endif
4292
4293_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS basic_string<char>)
4294_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS basic_string<wchar_t>)
4295_LIBCPP_EXTERN_TEMPLATE(string operator+<char, char_traits<char>, allocator<char> >(char const*, string const&))
4296
4297_LIBCPP_END_NAMESPACE_STD
4298
4299#endif  // _LIBCPP_STRING
4300