xref: /freebsd-12.1/contrib/libc++/include/string (revision 2b375b4e)
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,
102                 const allocator_type& a = allocator_type());
103    basic_string(const basic_string& str, size_type pos, size_type n,
104                 const Allocator& a = Allocator());
105    basic_string(const value_type* s, const allocator_type& a = allocator_type());
106    basic_string(const value_type* s, size_type n, const allocator_type& a = allocator_type());
107    basic_string(size_type n, value_type c, const allocator_type& a = allocator_type());
108    template<class InputIterator>
109        basic_string(InputIterator begin, InputIterator end,
110                     const allocator_type& a = allocator_type());
111    basic_string(initializer_list<value_type>, const Allocator& = Allocator());
112    basic_string(const basic_string&, const Allocator&);
113    basic_string(basic_string&&, const Allocator&);
114
115    ~basic_string();
116
117    basic_string& operator=(const basic_string& str);
118    basic_string& operator=(basic_string&& str)
119        noexcept(
120             allocator_type::propagate_on_container_move_assignment::value ||
121             allocator_type::is_always_equal::value ); // C++17
122    basic_string& operator=(const value_type* s);
123    basic_string& operator=(value_type c);
124    basic_string& operator=(initializer_list<value_type>);
125
126    iterator       begin() noexcept;
127    const_iterator begin() const noexcept;
128    iterator       end() noexcept;
129    const_iterator end() const noexcept;
130
131    reverse_iterator       rbegin() noexcept;
132    const_reverse_iterator rbegin() const noexcept;
133    reverse_iterator       rend() noexcept;
134    const_reverse_iterator rend() const noexcept;
135
136    const_iterator         cbegin() const noexcept;
137    const_iterator         cend() const noexcept;
138    const_reverse_iterator crbegin() const noexcept;
139    const_reverse_iterator crend() const noexcept;
140
141    size_type size() const noexcept;
142    size_type length() const noexcept;
143    size_type max_size() const noexcept;
144    size_type capacity() const noexcept;
145
146    void resize(size_type n, value_type c);
147    void resize(size_type n);
148
149    void reserve(size_type res_arg = 0);
150    void shrink_to_fit();
151    void clear() noexcept;
152    bool empty() const noexcept;
153
154    const_reference operator[](size_type pos) const;
155    reference       operator[](size_type pos);
156
157    const_reference at(size_type n) const;
158    reference       at(size_type n);
159
160    basic_string& operator+=(const basic_string& str);
161    basic_string& operator+=(const value_type* s);
162    basic_string& operator+=(value_type c);
163    basic_string& operator+=(initializer_list<value_type>);
164
165    basic_string& append(const basic_string& str);
166    basic_string& append(const basic_string& str, size_type pos, size_type n=npos); //C++14
167    basic_string& append(const value_type* s, size_type n);
168    basic_string& append(const value_type* s);
169    basic_string& append(size_type n, value_type c);
170    template<class InputIterator>
171        basic_string& append(InputIterator first, InputIterator last);
172    basic_string& append(initializer_list<value_type>);
173
174    void push_back(value_type c);
175    void pop_back();
176    reference       front();
177    const_reference front() const;
178    reference       back();
179    const_reference back() const;
180
181    basic_string& assign(const basic_string& str);
182    basic_string& assign(basic_string&& str);
183    basic_string& assign(const basic_string& str, size_type pos, size_type n=npos); // C++14
184    basic_string& assign(const value_type* s, size_type n);
185    basic_string& assign(const value_type* s);
186    basic_string& assign(size_type n, value_type c);
187    template<class InputIterator>
188        basic_string& assign(InputIterator first, InputIterator last);
189    basic_string& assign(initializer_list<value_type>);
190
191    basic_string& insert(size_type pos1, const basic_string& str);
192    basic_string& insert(size_type pos1, const basic_string& str,
193                         size_type pos2, size_type n);
194    basic_string& insert(size_type pos, const value_type* s, size_type n=npos); //C++14
195    basic_string& insert(size_type pos, const value_type* s);
196    basic_string& insert(size_type pos, size_type n, value_type c);
197    iterator      insert(const_iterator p, value_type c);
198    iterator      insert(const_iterator p, size_type n, value_type c);
199    template<class InputIterator>
200        iterator insert(const_iterator p, InputIterator first, InputIterator last);
201    iterator      insert(const_iterator p, initializer_list<value_type>);
202
203    basic_string& erase(size_type pos = 0, size_type n = npos);
204    iterator      erase(const_iterator position);
205    iterator      erase(const_iterator first, const_iterator last);
206
207    basic_string& replace(size_type pos1, size_type n1, const basic_string& str);
208    basic_string& replace(size_type pos1, size_type n1, const basic_string& str,
209                          size_type pos2, size_type n2=npos); // C++14
210    basic_string& replace(size_type pos, size_type n1, const value_type* s, size_type n2);
211    basic_string& replace(size_type pos, size_type n1, const value_type* s);
212    basic_string& replace(size_type pos, size_type n1, size_type n2, value_type c);
213    basic_string& replace(const_iterator i1, const_iterator i2, const basic_string& str);
214    basic_string& replace(const_iterator i1, const_iterator i2, const value_type* s, size_type n);
215    basic_string& replace(const_iterator i1, const_iterator i2, const value_type* s);
216    basic_string& replace(const_iterator i1, const_iterator i2, size_type n, value_type c);
217    template<class InputIterator>
218        basic_string& replace(const_iterator i1, const_iterator i2, InputIterator j1, InputIterator j2);
219    basic_string& replace(const_iterator i1, const_iterator i2, initializer_list<value_type>);
220
221    size_type copy(value_type* s, size_type n, size_type pos = 0) const;
222    basic_string substr(size_type pos = 0, size_type n = npos) const;
223
224    void swap(basic_string& str)
225        noexcept(allocator_traits<allocator_type>::propagate_on_container_swap::value ||
226                 allocator_traits<allocator_type>::is_always_equal::value);  // C++17
227
228    const value_type* c_str() const noexcept;
229    const value_type* data() const noexcept;
230          value_type* data()       noexcept;   // C++17
231
232    allocator_type get_allocator() const noexcept;
233
234    size_type find(const basic_string& str, size_type pos = 0) const noexcept;
235    size_type find(const value_type* s, size_type pos, size_type n) const noexcept;
236    size_type find(const value_type* s, size_type pos = 0) const noexcept;
237    size_type find(value_type c, size_type pos = 0) const noexcept;
238
239    size_type rfind(const basic_string& str, size_type pos = npos) const noexcept;
240    size_type rfind(const value_type* s, size_type pos, size_type n) const noexcept;
241    size_type rfind(const value_type* s, size_type pos = npos) const noexcept;
242    size_type rfind(value_type c, size_type pos = npos) const noexcept;
243
244    size_type find_first_of(const basic_string& str, size_type pos = 0) const noexcept;
245    size_type find_first_of(const value_type* s, size_type pos, size_type n) const noexcept;
246    size_type find_first_of(const value_type* s, size_type pos = 0) const noexcept;
247    size_type find_first_of(value_type c, size_type pos = 0) const noexcept;
248
249    size_type find_last_of(const basic_string& str, size_type pos = npos) const noexcept;
250    size_type find_last_of(const value_type* s, size_type pos, size_type n) const noexcept;
251    size_type find_last_of(const value_type* s, size_type pos = npos) const noexcept;
252    size_type find_last_of(value_type c, size_type pos = npos) const noexcept;
253
254    size_type find_first_not_of(const basic_string& str, size_type pos = 0) const noexcept;
255    size_type find_first_not_of(const value_type* s, size_type pos, size_type n) const noexcept;
256    size_type find_first_not_of(const value_type* s, size_type pos = 0) const noexcept;
257    size_type find_first_not_of(value_type c, size_type pos = 0) const noexcept;
258
259    size_type find_last_not_of(const basic_string& str, size_type pos = npos) const noexcept;
260    size_type find_last_not_of(const value_type* s, size_type pos, size_type n) const noexcept;
261    size_type find_last_not_of(const value_type* s, size_type pos = npos) const noexcept;
262    size_type find_last_not_of(value_type c, size_type pos = npos) const noexcept;
263
264    int compare(const basic_string& str) const noexcept;
265    int compare(size_type pos1, size_type n1, const basic_string& str) const;
266    int compare(size_type pos1, size_type n1, const basic_string& str,
267                size_type pos2, size_type n2=npos) const; // C++14
268    int compare(const value_type* s) const noexcept;
269    int compare(size_type pos1, size_type n1, const value_type* s) const;
270    int compare(size_type pos1, size_type n1, const value_type* s, size_type n2) const;
271
272    bool __invariants() const;
273};
274
275template<class charT, class traits, class Allocator>
276basic_string<charT, traits, Allocator>
277operator+(const basic_string<charT, traits, Allocator>& lhs,
278          const basic_string<charT, traits, Allocator>& rhs);
279
280template<class charT, class traits, class Allocator>
281basic_string<charT, traits, Allocator>
282operator+(const charT* lhs , const basic_string<charT,traits,Allocator>&rhs);
283
284template<class charT, class traits, class Allocator>
285basic_string<charT, traits, Allocator>
286operator+(charT lhs, const basic_string<charT,traits,Allocator>& rhs);
287
288template<class charT, class traits, class Allocator>
289basic_string<charT, traits, Allocator>
290operator+(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);
291
292template<class charT, class traits, class Allocator>
293basic_string<charT, traits, Allocator>
294operator+(const basic_string<charT, traits, Allocator>& lhs, charT rhs);
295
296template<class charT, class traits, class Allocator>
297bool operator==(const basic_string<charT, traits, Allocator>& lhs,
298                const basic_string<charT, traits, Allocator>& rhs) noexcept;
299
300template<class charT, class traits, class Allocator>
301bool operator==(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
302
303template<class charT, class traits, class Allocator>
304bool operator==(const basic_string<charT,traits,Allocator>& lhs, const charT* rhs) noexcept;
305
306template<class charT, class traits, class Allocator>
307bool operator!=(const basic_string<charT,traits,Allocator>& lhs,
308                const basic_string<charT, traits, Allocator>& rhs) noexcept;
309
310template<class charT, class traits, class Allocator>
311bool operator!=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
312
313template<class charT, class traits, class Allocator>
314bool operator!=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
315
316template<class charT, class traits, class Allocator>
317bool operator< (const basic_string<charT, traits, Allocator>& lhs,
318                const basic_string<charT, traits, Allocator>& rhs) noexcept;
319
320template<class charT, class traits, class Allocator>
321bool operator< (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
322
323template<class charT, class traits, class Allocator>
324bool operator< (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
325
326template<class charT, class traits, class Allocator>
327bool operator> (const basic_string<charT, traits, Allocator>& lhs,
328                const basic_string<charT, traits, Allocator>& rhs) noexcept;
329
330template<class charT, class traits, class Allocator>
331bool operator> (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
332
333template<class charT, class traits, class Allocator>
334bool operator> (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
335
336template<class charT, class traits, class Allocator>
337bool operator<=(const basic_string<charT, traits, Allocator>& lhs,
338                const basic_string<charT, traits, Allocator>& rhs) noexcept;
339
340template<class charT, class traits, class Allocator>
341bool operator<=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
342
343template<class charT, class traits, class Allocator>
344bool operator<=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
345
346template<class charT, class traits, class Allocator>
347bool operator>=(const basic_string<charT, traits, Allocator>& lhs,
348                const basic_string<charT, traits, Allocator>& rhs) noexcept;
349
350template<class charT, class traits, class Allocator>
351bool operator>=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
352
353template<class charT, class traits, class Allocator>
354bool operator>=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
355
356template<class charT, class traits, class Allocator>
357void swap(basic_string<charT, traits, Allocator>& lhs,
358          basic_string<charT, traits, Allocator>& rhs)
359            noexcept(noexcept(lhs.swap(rhs)));
360
361template<class charT, class traits, class Allocator>
362basic_istream<charT, traits>&
363operator>>(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
364
365template<class charT, class traits, class Allocator>
366basic_ostream<charT, traits>&
367operator<<(basic_ostream<charT, traits>& os, const basic_string<charT, traits, Allocator>& str);
368
369template<class charT, class traits, class Allocator>
370basic_istream<charT, traits>&
371getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str,
372        charT delim);
373
374template<class charT, class traits, class Allocator>
375basic_istream<charT, traits>&
376getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
377
378typedef basic_string<char>    string;
379typedef basic_string<wchar_t> wstring;
380typedef basic_string<char16_t> u16string;
381typedef basic_string<char32_t> u32string;
382
383int                stoi  (const string& str, size_t* idx = 0, int base = 10);
384long               stol  (const string& str, size_t* idx = 0, int base = 10);
385unsigned long      stoul (const string& str, size_t* idx = 0, int base = 10);
386long long          stoll (const string& str, size_t* idx = 0, int base = 10);
387unsigned long long stoull(const string& str, size_t* idx = 0, int base = 10);
388
389float       stof (const string& str, size_t* idx = 0);
390double      stod (const string& str, size_t* idx = 0);
391long double stold(const string& str, size_t* idx = 0);
392
393string to_string(int val);
394string to_string(unsigned val);
395string to_string(long val);
396string to_string(unsigned long val);
397string to_string(long long val);
398string to_string(unsigned long long val);
399string to_string(float val);
400string to_string(double val);
401string to_string(long double val);
402
403int                stoi  (const wstring& str, size_t* idx = 0, int base = 10);
404long               stol  (const wstring& str, size_t* idx = 0, int base = 10);
405unsigned long      stoul (const wstring& str, size_t* idx = 0, int base = 10);
406long long          stoll (const wstring& str, size_t* idx = 0, int base = 10);
407unsigned long long stoull(const wstring& str, size_t* idx = 0, int base = 10);
408
409float       stof (const wstring& str, size_t* idx = 0);
410double      stod (const wstring& str, size_t* idx = 0);
411long double stold(const wstring& str, size_t* idx = 0);
412
413wstring to_wstring(int val);
414wstring to_wstring(unsigned val);
415wstring to_wstring(long val);
416wstring to_wstring(unsigned long val);
417wstring to_wstring(long long val);
418wstring to_wstring(unsigned long long val);
419wstring to_wstring(float val);
420wstring to_wstring(double val);
421wstring to_wstring(long double val);
422
423template <> struct hash<string>;
424template <> struct hash<u16string>;
425template <> struct hash<u32string>;
426template <> struct hash<wstring>;
427
428basic_string<char>     operator "" s( const char *str,     size_t len ); // C++14
429basic_string<wchar_t>  operator "" s( const wchar_t *str,  size_t len ); // C++14
430basic_string<char16_t> operator "" s( const char16_t *str, size_t len ); // C++14
431basic_string<char32_t> operator "" s( const char32_t *str, size_t len ); // C++14
432
433}  // std
434
435*/
436
437#include <__config>
438#include <iosfwd>
439#include <cstring>
440#include <cstdio>  // For EOF.
441#include <cwchar>
442#include <algorithm>
443#include <iterator>
444#include <utility>
445#include <memory>
446#include <stdexcept>
447#include <type_traits>
448#include <initializer_list>
449#include <__functional_base>
450#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
451#include <cstdint>
452#endif
453#if defined(_LIBCPP_NO_EXCEPTIONS)
454#include <cassert>
455#endif
456
457#include <__undef_min_max>
458
459#include <__debug>
460
461#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
462#pragma GCC system_header
463#endif
464
465_LIBCPP_BEGIN_NAMESPACE_STD
466
467// fpos
468
469template <class _StateT>
470class _LIBCPP_TYPE_VIS_ONLY fpos
471{
472private:
473    _StateT __st_;
474    streamoff __off_;
475public:
476    _LIBCPP_INLINE_VISIBILITY fpos(streamoff __off = streamoff()) : __st_(), __off_(__off) {}
477
478    _LIBCPP_INLINE_VISIBILITY operator streamoff() const {return __off_;}
479
480    _LIBCPP_INLINE_VISIBILITY _StateT state() const {return __st_;}
481    _LIBCPP_INLINE_VISIBILITY void state(_StateT __st) {__st_ = __st;}
482
483    _LIBCPP_INLINE_VISIBILITY fpos& operator+=(streamoff __off) {__off_ += __off; return *this;}
484    _LIBCPP_INLINE_VISIBILITY fpos  operator+ (streamoff __off) const {fpos __t(*this); __t += __off; return __t;}
485    _LIBCPP_INLINE_VISIBILITY fpos& operator-=(streamoff __off) {__off_ -= __off; return *this;}
486    _LIBCPP_INLINE_VISIBILITY fpos  operator- (streamoff __off) const {fpos __t(*this); __t -= __off; return __t;}
487};
488
489template <class _StateT>
490inline _LIBCPP_INLINE_VISIBILITY
491streamoff operator-(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
492    {return streamoff(__x) - streamoff(__y);}
493
494template <class _StateT>
495inline _LIBCPP_INLINE_VISIBILITY
496bool operator==(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
497    {return streamoff(__x) == streamoff(__y);}
498
499template <class _StateT>
500inline _LIBCPP_INLINE_VISIBILITY
501bool operator!=(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
502    {return streamoff(__x) != streamoff(__y);}
503
504// char_traits
505
506template <class _CharT>
507struct _LIBCPP_TYPE_VIS_ONLY char_traits
508{
509    typedef _CharT    char_type;
510    typedef int       int_type;
511    typedef streamoff off_type;
512    typedef streampos pos_type;
513    typedef mbstate_t state_type;
514
515    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
516        {__c1 = __c2;}
517    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
518        {return __c1 == __c2;}
519    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
520        {return __c1 < __c2;}
521
522    static int              compare(const char_type* __s1, const char_type* __s2, size_t __n);
523    _LIBCPP_INLINE_VISIBILITY
524    static size_t           length(const char_type* __s);
525    _LIBCPP_INLINE_VISIBILITY
526    static const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
527    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
528    _LIBCPP_INLINE_VISIBILITY
529    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
530    _LIBCPP_INLINE_VISIBILITY
531    static char_type*       assign(char_type* __s, size_t __n, char_type __a);
532
533    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
534        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
535    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
536        {return char_type(__c);}
537    static inline _LIBCPP_CONSTEXPR int_type  to_int_type(char_type __c) _NOEXCEPT
538        {return int_type(__c);}
539    static inline _LIBCPP_CONSTEXPR bool      eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
540        {return __c1 == __c2;}
541    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
542        {return int_type(EOF);}
543};
544
545template <class _CharT>
546int
547char_traits<_CharT>::compare(const char_type* __s1, const char_type* __s2, size_t __n)
548{
549    for (; __n; --__n, ++__s1, ++__s2)
550    {
551        if (lt(*__s1, *__s2))
552            return -1;
553        if (lt(*__s2, *__s1))
554            return 1;
555    }
556    return 0;
557}
558
559template <class _CharT>
560inline
561size_t
562char_traits<_CharT>::length(const char_type* __s)
563{
564    size_t __len = 0;
565    for (; !eq(*__s, char_type(0)); ++__s)
566        ++__len;
567    return __len;
568}
569
570template <class _CharT>
571inline
572const _CharT*
573char_traits<_CharT>::find(const char_type* __s, size_t __n, const char_type& __a)
574{
575    for (; __n; --__n)
576    {
577        if (eq(*__s, __a))
578            return __s;
579        ++__s;
580    }
581    return 0;
582}
583
584template <class _CharT>
585_CharT*
586char_traits<_CharT>::move(char_type* __s1, const char_type* __s2, size_t __n)
587{
588    char_type* __r = __s1;
589    if (__s1 < __s2)
590    {
591        for (; __n; --__n, ++__s1, ++__s2)
592            assign(*__s1, *__s2);
593    }
594    else if (__s2 < __s1)
595    {
596        __s1 += __n;
597        __s2 += __n;
598        for (; __n; --__n)
599            assign(*--__s1, *--__s2);
600    }
601    return __r;
602}
603
604template <class _CharT>
605inline
606_CharT*
607char_traits<_CharT>::copy(char_type* __s1, const char_type* __s2, size_t __n)
608{
609    _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
610    char_type* __r = __s1;
611    for (; __n; --__n, ++__s1, ++__s2)
612        assign(*__s1, *__s2);
613    return __r;
614}
615
616template <class _CharT>
617inline
618_CharT*
619char_traits<_CharT>::assign(char_type* __s, size_t __n, char_type __a)
620{
621    char_type* __r = __s;
622    for (; __n; --__n, ++__s)
623        assign(*__s, __a);
624    return __r;
625}
626
627// char_traits<char>
628
629template <>
630struct _LIBCPP_TYPE_VIS_ONLY char_traits<char>
631{
632    typedef char      char_type;
633    typedef int       int_type;
634    typedef streamoff off_type;
635    typedef streampos pos_type;
636    typedef mbstate_t state_type;
637
638    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
639        {__c1 = __c2;}
640    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
641            {return __c1 == __c2;}
642    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
643        {return (unsigned char)__c1 < (unsigned char)__c2;}
644
645    static inline int compare(const char_type* __s1, const char_type* __s2, size_t __n)
646        {return __n == 0 ? 0 : memcmp(__s1, __s2, __n);}
647    static inline size_t length(const char_type* __s) {return strlen(__s);}
648    static inline const char_type* find(const char_type* __s, size_t __n, const char_type& __a)
649        {return __n == 0 ? NULL : (const char_type*) memchr(__s, to_int_type(__a), __n);}
650    static inline char_type* move(char_type* __s1, const char_type* __s2, size_t __n)
651        {return __n == 0 ? __s1 : (char_type*) memmove(__s1, __s2, __n);}
652    static inline char_type* copy(char_type* __s1, const char_type* __s2, size_t __n)
653        {
654            _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
655            return __n == 0 ? __s1 : (char_type*)memcpy(__s1, __s2, __n);
656        }
657    static inline char_type* assign(char_type* __s, size_t __n, char_type __a)
658        {return __n == 0 ? __s : (char_type*)memset(__s, to_int_type(__a), __n);}
659
660    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
661        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
662    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
663        {return char_type(__c);}
664    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
665        {return int_type((unsigned char)__c);}
666    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
667        {return __c1 == __c2;}
668    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
669        {return int_type(EOF);}
670};
671
672// char_traits<wchar_t>
673
674template <>
675struct _LIBCPP_TYPE_VIS_ONLY char_traits<wchar_t>
676{
677    typedef wchar_t   char_type;
678    typedef wint_t    int_type;
679    typedef streamoff off_type;
680    typedef streampos pos_type;
681    typedef mbstate_t state_type;
682
683    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
684        {__c1 = __c2;}
685    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
686        {return __c1 == __c2;}
687    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
688        {return __c1 < __c2;}
689
690    static inline int compare(const char_type* __s1, const char_type* __s2, size_t __n)
691        {return __n == 0 ? 0 : wmemcmp(__s1, __s2, __n);}
692    static inline size_t length(const char_type* __s)
693        {return wcslen(__s);}
694    static inline const char_type* find(const char_type* __s, size_t __n, const char_type& __a)
695        {return __n == 0 ? NULL : (const char_type*)wmemchr(__s, __a, __n);}
696    static inline char_type* move(char_type* __s1, const char_type* __s2, size_t __n)
697        {return __n == 0 ? __s1 : (char_type*)wmemmove(__s1, __s2, __n);}
698    static inline char_type* copy(char_type* __s1, const char_type* __s2, size_t __n)
699        {
700            _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
701            return __n == 0 ? __s1 : (char_type*)wmemcpy(__s1, __s2, __n);
702        }
703    static inline char_type* assign(char_type* __s, size_t __n, char_type __a)
704        {return __n == 0 ? __s : (char_type*)wmemset(__s, __a, __n);}
705
706    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
707        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
708    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
709        {return char_type(__c);}
710    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
711        {return int_type(__c);}
712    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
713        {return __c1 == __c2;}
714    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
715        {return int_type(WEOF);}
716};
717
718#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
719
720template <>
721struct _LIBCPP_TYPE_VIS_ONLY char_traits<char16_t>
722{
723    typedef char16_t       char_type;
724    typedef uint_least16_t int_type;
725    typedef streamoff      off_type;
726    typedef u16streampos   pos_type;
727    typedef mbstate_t      state_type;
728
729    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
730        {__c1 = __c2;}
731    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
732        {return __c1 == __c2;}
733    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
734        {return __c1 < __c2;}
735
736    _LIBCPP_INLINE_VISIBILITY
737    static int              compare(const char_type* __s1, const char_type* __s2, size_t __n);
738    _LIBCPP_INLINE_VISIBILITY
739    static size_t           length(const char_type* __s);
740    _LIBCPP_INLINE_VISIBILITY
741    static const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
742    _LIBCPP_INLINE_VISIBILITY
743    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
744    _LIBCPP_INLINE_VISIBILITY
745    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
746    _LIBCPP_INLINE_VISIBILITY
747    static char_type*       assign(char_type* __s, size_t __n, char_type __a);
748
749    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
750        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
751    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
752        {return char_type(__c);}
753    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
754        {return int_type(__c);}
755    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
756        {return __c1 == __c2;}
757    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
758        {return int_type(0xFFFF);}
759};
760
761inline
762int
763char_traits<char16_t>::compare(const char_type* __s1, const char_type* __s2, size_t __n)
764{
765    for (; __n; --__n, ++__s1, ++__s2)
766    {
767        if (lt(*__s1, *__s2))
768            return -1;
769        if (lt(*__s2, *__s1))
770            return 1;
771    }
772    return 0;
773}
774
775inline
776size_t
777char_traits<char16_t>::length(const char_type* __s)
778{
779    size_t __len = 0;
780    for (; !eq(*__s, char_type(0)); ++__s)
781        ++__len;
782    return __len;
783}
784
785inline
786const char16_t*
787char_traits<char16_t>::find(const char_type* __s, size_t __n, const char_type& __a)
788{
789    for (; __n; --__n)
790    {
791        if (eq(*__s, __a))
792            return __s;
793        ++__s;
794    }
795    return 0;
796}
797
798inline
799char16_t*
800char_traits<char16_t>::move(char_type* __s1, const char_type* __s2, size_t __n)
801{
802    char_type* __r = __s1;
803    if (__s1 < __s2)
804    {
805        for (; __n; --__n, ++__s1, ++__s2)
806            assign(*__s1, *__s2);
807    }
808    else if (__s2 < __s1)
809    {
810        __s1 += __n;
811        __s2 += __n;
812        for (; __n; --__n)
813            assign(*--__s1, *--__s2);
814    }
815    return __r;
816}
817
818inline
819char16_t*
820char_traits<char16_t>::copy(char_type* __s1, const char_type* __s2, size_t __n)
821{
822    _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
823    char_type* __r = __s1;
824    for (; __n; --__n, ++__s1, ++__s2)
825        assign(*__s1, *__s2);
826    return __r;
827}
828
829inline
830char16_t*
831char_traits<char16_t>::assign(char_type* __s, size_t __n, char_type __a)
832{
833    char_type* __r = __s;
834    for (; __n; --__n, ++__s)
835        assign(*__s, __a);
836    return __r;
837}
838
839template <>
840struct _LIBCPP_TYPE_VIS_ONLY char_traits<char32_t>
841{
842    typedef char32_t       char_type;
843    typedef uint_least32_t int_type;
844    typedef streamoff      off_type;
845    typedef u32streampos   pos_type;
846    typedef mbstate_t      state_type;
847
848    static inline void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT
849        {__c1 = __c2;}
850    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
851        {return __c1 == __c2;}
852    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
853        {return __c1 < __c2;}
854
855    _LIBCPP_INLINE_VISIBILITY
856    static int              compare(const char_type* __s1, const char_type* __s2, size_t __n);
857    _LIBCPP_INLINE_VISIBILITY
858    static size_t           length(const char_type* __s);
859    _LIBCPP_INLINE_VISIBILITY
860    static const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
861    _LIBCPP_INLINE_VISIBILITY
862    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
863    _LIBCPP_INLINE_VISIBILITY
864    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
865    _LIBCPP_INLINE_VISIBILITY
866    static char_type*       assign(char_type* __s, size_t __n, char_type __a);
867
868    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
869        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
870    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
871        {return char_type(__c);}
872    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
873        {return int_type(__c);}
874    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
875        {return __c1 == __c2;}
876    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
877        {return int_type(0xFFFFFFFF);}
878};
879
880inline
881int
882char_traits<char32_t>::compare(const char_type* __s1, const char_type* __s2, size_t __n)
883{
884    for (; __n; --__n, ++__s1, ++__s2)
885    {
886        if (lt(*__s1, *__s2))
887            return -1;
888        if (lt(*__s2, *__s1))
889            return 1;
890    }
891    return 0;
892}
893
894inline
895size_t
896char_traits<char32_t>::length(const char_type* __s)
897{
898    size_t __len = 0;
899    for (; !eq(*__s, char_type(0)); ++__s)
900        ++__len;
901    return __len;
902}
903
904inline
905const char32_t*
906char_traits<char32_t>::find(const char_type* __s, size_t __n, const char_type& __a)
907{
908    for (; __n; --__n)
909    {
910        if (eq(*__s, __a))
911            return __s;
912        ++__s;
913    }
914    return 0;
915}
916
917inline
918char32_t*
919char_traits<char32_t>::move(char_type* __s1, const char_type* __s2, size_t __n)
920{
921    char_type* __r = __s1;
922    if (__s1 < __s2)
923    {
924        for (; __n; --__n, ++__s1, ++__s2)
925            assign(*__s1, *__s2);
926    }
927    else if (__s2 < __s1)
928    {
929        __s1 += __n;
930        __s2 += __n;
931        for (; __n; --__n)
932            assign(*--__s1, *--__s2);
933    }
934    return __r;
935}
936
937inline
938char32_t*
939char_traits<char32_t>::copy(char_type* __s1, const char_type* __s2, size_t __n)
940{
941    _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
942    char_type* __r = __s1;
943    for (; __n; --__n, ++__s1, ++__s2)
944        assign(*__s1, *__s2);
945    return __r;
946}
947
948inline
949char32_t*
950char_traits<char32_t>::assign(char_type* __s, size_t __n, char_type __a)
951{
952    char_type* __r = __s;
953    for (; __n; --__n, ++__s)
954        assign(*__s, __a);
955    return __r;
956}
957
958#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
959
960// helper fns for basic_string
961
962// __str_find
963template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
964inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
965__str_find(const _CharT *__p, _SizeT __sz,
966             _CharT __c, _SizeT __pos) _NOEXCEPT
967{
968    if (__pos >= __sz)
969        return __npos;
970    const _CharT* __r = _Traits::find(__p + __pos, __sz - __pos, __c);
971    if (__r == 0)
972        return __npos;
973    return static_cast<_SizeT>(__r - __p);
974}
975
976template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
977inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
978__str_find(const _CharT *__p, _SizeT __sz,
979       const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
980{
981    if (__pos > __sz || __sz - __pos < __n)
982        return __npos;
983    if (__n == 0)
984        return __pos;
985    const _CharT* __r =
986        _VSTD::__search(__p + __pos, __p + __sz,
987                        __s, __s + __n, _Traits::eq,
988                        random_access_iterator_tag(), random_access_iterator_tag()).first;
989    if (__r == __p + __sz)
990        return __npos;
991    return static_cast<_SizeT>(__r - __p);
992}
993
994
995// __str_rfind
996
997template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
998inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
999__str_rfind(const _CharT *__p, _SizeT __sz,
1000              _CharT __c, _SizeT __pos) _NOEXCEPT
1001{
1002    if (__sz < 1)
1003        return __npos;
1004    if (__pos < __sz)
1005        ++__pos;
1006    else
1007        __pos = __sz;
1008    for (const _CharT* __ps = __p + __pos; __ps != __p;)
1009    {
1010        if (_Traits::eq(*--__ps, __c))
1011            return static_cast<_SizeT>(__ps - __p);
1012    }
1013    return __npos;
1014}
1015
1016template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1017inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1018__str_rfind(const _CharT *__p, _SizeT __sz,
1019        const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1020{
1021    __pos = _VSTD::min(__pos, __sz);
1022    if (__n < __sz - __pos)
1023        __pos += __n;
1024    else
1025        __pos = __sz;
1026    const _CharT* __r = _VSTD::__find_end(
1027                  __p, __p + __pos, __s, __s + __n, _Traits::eq,
1028                        random_access_iterator_tag(), random_access_iterator_tag());
1029    if (__n > 0 && __r == __p + __pos)
1030        return __npos;
1031    return static_cast<_SizeT>(__r - __p);
1032}
1033
1034// __str_find_first_of
1035template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1036inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1037__str_find_first_of(const _CharT *__p, _SizeT __sz,
1038                const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1039{
1040    if (__pos >= __sz || __n == 0)
1041        return __npos;
1042    const _CharT* __r = _VSTD::__find_first_of_ce
1043        (__p + __pos, __p + __sz, __s, __s + __n, _Traits::eq );
1044    if (__r == __p + __sz)
1045        return __npos;
1046    return static_cast<_SizeT>(__r - __p);
1047}
1048
1049
1050// __str_find_last_of
1051template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1052inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1053__str_find_last_of(const _CharT *__p, _SizeT __sz,
1054               const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1055    {
1056    if (__n != 0)
1057    {
1058        if (__pos < __sz)
1059            ++__pos;
1060        else
1061            __pos = __sz;
1062        for (const _CharT* __ps = __p + __pos; __ps != __p;)
1063        {
1064            const _CharT* __r = _Traits::find(__s, __n, *--__ps);
1065            if (__r)
1066                return static_cast<_SizeT>(__ps - __p);
1067        }
1068    }
1069    return __npos;
1070}
1071
1072
1073// __str_find_first_not_of
1074template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1075inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1076__str_find_first_not_of(const _CharT *__p, _SizeT __sz,
1077                    const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1078{
1079    if (__pos < __sz)
1080    {
1081        const _CharT* __pe = __p + __sz;
1082        for (const _CharT* __ps = __p + __pos; __ps != __pe; ++__ps)
1083            if (_Traits::find(__s, __n, *__ps) == 0)
1084                return static_cast<_SizeT>(__ps - __p);
1085    }
1086    return __npos;
1087}
1088
1089
1090template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1091inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1092__str_find_first_not_of(const _CharT *__p, _SizeT __sz,
1093                          _CharT __c, _SizeT __pos) _NOEXCEPT
1094{
1095    if (__pos < __sz)
1096    {
1097        const _CharT* __pe = __p + __sz;
1098        for (const _CharT* __ps = __p + __pos; __ps != __pe; ++__ps)
1099            if (!_Traits::eq(*__ps, __c))
1100                return static_cast<_SizeT>(__ps - __p);
1101    }
1102    return __npos;
1103}
1104
1105
1106// __str_find_last_not_of
1107template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1108inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1109__str_find_last_not_of(const _CharT *__p, _SizeT __sz,
1110                   const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
1111{
1112    if (__pos < __sz)
1113        ++__pos;
1114    else
1115        __pos = __sz;
1116    for (const _CharT* __ps = __p + __pos; __ps != __p;)
1117        if (_Traits::find(__s, __n, *--__ps) == 0)
1118            return static_cast<_SizeT>(__ps - __p);
1119    return __npos;
1120}
1121
1122
1123template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
1124inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1125__str_find_last_not_of(const _CharT *__p, _SizeT __sz,
1126                         _CharT __c, _SizeT __pos) _NOEXCEPT
1127{
1128    if (__pos < __sz)
1129        ++__pos;
1130    else
1131        __pos = __sz;
1132    for (const _CharT* __ps = __p + __pos; __ps != __p;)
1133        if (!_Traits::eq(*--__ps, __c))
1134            return static_cast<_SizeT>(__ps - __p);
1135    return __npos;
1136}
1137
1138template<class _Ptr>
1139size_t _LIBCPP_INLINE_VISIBILITY __do_string_hash(_Ptr __p, _Ptr __e)
1140{
1141    typedef typename iterator_traits<_Ptr>::value_type value_type;
1142    return __murmur2_or_cityhash<size_t>()(__p, (__e-__p)*sizeof(value_type));
1143}
1144
1145// basic_string
1146
1147template<class _CharT, class _Traits, class _Allocator>
1148basic_string<_CharT, _Traits, _Allocator>
1149operator+(const basic_string<_CharT, _Traits, _Allocator>& __x,
1150          const basic_string<_CharT, _Traits, _Allocator>& __y);
1151
1152template<class _CharT, class _Traits, class _Allocator>
1153basic_string<_CharT, _Traits, _Allocator>
1154operator+(const _CharT* __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
1155
1156template<class _CharT, class _Traits, class _Allocator>
1157basic_string<_CharT, _Traits, _Allocator>
1158operator+(_CharT __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
1159
1160template<class _CharT, class _Traits, class _Allocator>
1161basic_string<_CharT, _Traits, _Allocator>
1162operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, const _CharT* __y);
1163
1164template<class _CharT, class _Traits, class _Allocator>
1165basic_string<_CharT, _Traits, _Allocator>
1166operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, _CharT __y);
1167
1168template <bool>
1169class _LIBCPP_TYPE_VIS_ONLY __basic_string_common
1170{
1171protected:
1172    void __throw_length_error() const;
1173    void __throw_out_of_range() const;
1174};
1175
1176template <bool __b>
1177void
1178__basic_string_common<__b>::__throw_length_error() const
1179{
1180#ifndef _LIBCPP_NO_EXCEPTIONS
1181    throw length_error("basic_string");
1182#else
1183    assert(!"basic_string length_error");
1184#endif
1185}
1186
1187template <bool __b>
1188void
1189__basic_string_common<__b>::__throw_out_of_range() const
1190{
1191#ifndef _LIBCPP_NO_EXCEPTIONS
1192    throw out_of_range("basic_string");
1193#else
1194    assert(!"basic_string out_of_range");
1195#endif
1196}
1197
1198#ifdef _LIBCPP_MSVC
1199#pragma warning( push )
1200#pragma warning( disable: 4231 )
1201#endif // _LIBCPP_MSVC
1202_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS __basic_string_common<true>)
1203#ifdef _LIBCPP_MSVC
1204#pragma warning( pop )
1205#endif // _LIBCPP_MSVC
1206
1207#ifdef _LIBCPP_NO_EXCEPTIONS
1208template <class _Iter>
1209struct __libcpp_string_gets_noexcept_iterator_impl : public true_type {};
1210#elif defined(_LIBCPP_HAS_NO_NOEXCEPT)
1211template <class _Iter>
1212struct __libcpp_string_gets_noexcept_iterator_impl : public false_type {};
1213#else
1214template <class _Iter, bool = __is_forward_iterator<_Iter>::value>
1215struct __libcpp_string_gets_noexcept_iterator_impl : public _LIBCPP_BOOL_CONSTANT((
1216    noexcept(++(declval<_Iter&>())) &&
1217    is_nothrow_assignable<_Iter&, _Iter>::value &&
1218    noexcept(declval<_Iter>() == declval<_Iter>()) &&
1219    noexcept(*declval<_Iter>())
1220)) {};
1221
1222template <class _Iter>
1223struct __libcpp_string_gets_noexcept_iterator_impl<_Iter, false> : public false_type {};
1224#endif
1225
1226
1227template <class _Iter>
1228struct __libcpp_string_gets_noexcept_iterator
1229    : public _LIBCPP_BOOL_CONSTANT(__libcpp_is_trivial_iterator<_Iter>::value || __libcpp_string_gets_noexcept_iterator_impl<_Iter>::value) {};
1230
1231#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1232
1233template <class _CharT, size_t = sizeof(_CharT)>
1234struct __padding
1235{
1236    unsigned char __xx[sizeof(_CharT)-1];
1237};
1238
1239template <class _CharT>
1240struct __padding<_CharT, 1>
1241{
1242};
1243
1244#endif  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1245
1246template<class _CharT, class _Traits, class _Allocator>
1247class _LIBCPP_TYPE_VIS_ONLY basic_string
1248    : private __basic_string_common<true>
1249{
1250public:
1251    typedef basic_string                                 __self;
1252    typedef _Traits                                      traits_type;
1253    typedef typename traits_type::char_type              value_type;
1254    typedef _Allocator                                   allocator_type;
1255    typedef allocator_traits<allocator_type>             __alloc_traits;
1256    typedef typename __alloc_traits::size_type           size_type;
1257    typedef typename __alloc_traits::difference_type     difference_type;
1258    typedef value_type&                                  reference;
1259    typedef const value_type&                            const_reference;
1260    typedef typename __alloc_traits::pointer             pointer;
1261    typedef typename __alloc_traits::const_pointer       const_pointer;
1262
1263    static_assert(is_pod<value_type>::value, "Character type of basic_string must be a POD");
1264    static_assert((is_same<_CharT, value_type>::value),
1265                  "traits_type::char_type must be the same type as CharT");
1266    static_assert((is_same<typename allocator_type::value_type, value_type>::value),
1267                  "Allocator::value_type must be same type as value_type");
1268#if defined(_LIBCPP_RAW_ITERATORS)
1269    typedef pointer                                      iterator;
1270    typedef const_pointer                                const_iterator;
1271#else  // defined(_LIBCPP_RAW_ITERATORS)
1272    typedef __wrap_iter<pointer>                         iterator;
1273    typedef __wrap_iter<const_pointer>                   const_iterator;
1274#endif  // defined(_LIBCPP_RAW_ITERATORS)
1275    typedef _VSTD::reverse_iterator<iterator>             reverse_iterator;
1276    typedef _VSTD::reverse_iterator<const_iterator>       const_reverse_iterator;
1277
1278private:
1279
1280#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1281
1282    struct __long
1283    {
1284        pointer   __data_;
1285        size_type __size_;
1286        size_type __cap_;
1287    };
1288
1289#if _LIBCPP_BIG_ENDIAN
1290    enum {__short_mask = 0x01};
1291    enum {__long_mask  = 0x1ul};
1292#else  // _LIBCPP_BIG_ENDIAN
1293    enum {__short_mask = 0x80};
1294    enum {__long_mask  = ~(size_type(~0) >> 1)};
1295#endif  // _LIBCPP_BIG_ENDIAN
1296
1297    enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
1298                      (sizeof(__long) - 1)/sizeof(value_type) : 2};
1299
1300    struct __short
1301    {
1302        value_type __data_[__min_cap];
1303        struct
1304            : __padding<value_type>
1305        {
1306            unsigned char __size_;
1307        };
1308    };
1309
1310#else
1311
1312    struct __long
1313    {
1314        size_type __cap_;
1315        size_type __size_;
1316        pointer   __data_;
1317    };
1318
1319#if _LIBCPP_BIG_ENDIAN
1320    enum {__short_mask = 0x80};
1321    enum {__long_mask  = ~(size_type(~0) >> 1)};
1322#else  // _LIBCPP_BIG_ENDIAN
1323    enum {__short_mask = 0x01};
1324    enum {__long_mask  = 0x1ul};
1325#endif  // _LIBCPP_BIG_ENDIAN
1326
1327    enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
1328                      (sizeof(__long) - 1)/sizeof(value_type) : 2};
1329
1330    struct __short
1331    {
1332        union
1333        {
1334            unsigned char __size_;
1335            value_type __lx;
1336        };
1337        value_type __data_[__min_cap];
1338    };
1339
1340#endif  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1341
1342    union __ulx{__long __lx; __short __lxx;};
1343
1344    enum {__n_words = sizeof(__ulx) / sizeof(size_type)};
1345
1346    struct __raw
1347    {
1348        size_type __words[__n_words];
1349    };
1350
1351    struct __rep
1352    {
1353        union
1354        {
1355            __long  __l;
1356            __short __s;
1357            __raw   __r;
1358        };
1359    };
1360
1361    __compressed_pair<__rep, allocator_type> __r_;
1362
1363public:
1364    static const size_type npos = -1;
1365
1366    _LIBCPP_INLINE_VISIBILITY basic_string()
1367        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value);
1368
1369    _LIBCPP_INLINE_VISIBILITY explicit basic_string(const allocator_type& __a)
1370#if _LIBCPP_STD_VER <= 14
1371        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value);
1372#else
1373        _NOEXCEPT;
1374#endif
1375
1376    basic_string(const basic_string& __str);
1377    basic_string(const basic_string& __str, const allocator_type& __a);
1378
1379#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1380    _LIBCPP_INLINE_VISIBILITY
1381    basic_string(basic_string&& __str)
1382#if _LIBCPP_STD_VER <= 14
1383        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
1384#else
1385        _NOEXCEPT;
1386#endif
1387
1388    _LIBCPP_INLINE_VISIBILITY
1389    basic_string(basic_string&& __str, const allocator_type& __a);
1390#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
1391    _LIBCPP_INLINE_VISIBILITY basic_string(const value_type* __s);
1392    _LIBCPP_INLINE_VISIBILITY
1393    basic_string(const value_type* __s, const allocator_type& __a);
1394    _LIBCPP_INLINE_VISIBILITY
1395    basic_string(const value_type* __s, size_type __n);
1396    _LIBCPP_INLINE_VISIBILITY
1397    basic_string(const value_type* __s, size_type __n, const allocator_type& __a);
1398    _LIBCPP_INLINE_VISIBILITY
1399    basic_string(size_type __n, value_type __c);
1400    _LIBCPP_INLINE_VISIBILITY
1401    basic_string(size_type __n, value_type __c, const allocator_type& __a);
1402    basic_string(const basic_string& __str, size_type __pos, size_type __n,
1403                 const allocator_type& __a = allocator_type());
1404    _LIBCPP_INLINE_VISIBILITY
1405    basic_string(const basic_string& __str, size_type __pos,
1406                 const allocator_type& __a = allocator_type());
1407    template<class _InputIterator>
1408        _LIBCPP_INLINE_VISIBILITY
1409        basic_string(_InputIterator __first, _InputIterator __last);
1410    template<class _InputIterator>
1411        _LIBCPP_INLINE_VISIBILITY
1412        basic_string(_InputIterator __first, _InputIterator __last, const allocator_type& __a);
1413#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1414    _LIBCPP_INLINE_VISIBILITY
1415    basic_string(initializer_list<value_type> __il);
1416    _LIBCPP_INLINE_VISIBILITY
1417    basic_string(initializer_list<value_type> __il, const allocator_type& __a);
1418#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1419
1420    ~basic_string();
1421
1422    basic_string& operator=(const basic_string& __str);
1423#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1424    _LIBCPP_INLINE_VISIBILITY
1425    basic_string& operator=(basic_string&& __str)
1426        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value));
1427#endif
1428    _LIBCPP_INLINE_VISIBILITY basic_string& operator=(const value_type* __s) {return assign(__s);}
1429    basic_string& operator=(value_type __c);
1430#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1431    _LIBCPP_INLINE_VISIBILITY
1432    basic_string& operator=(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
1433#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1434
1435#if _LIBCPP_DEBUG_LEVEL >= 2
1436    _LIBCPP_INLINE_VISIBILITY
1437    iterator begin() _NOEXCEPT
1438        {return iterator(this, __get_pointer());}
1439    _LIBCPP_INLINE_VISIBILITY
1440    const_iterator begin() const _NOEXCEPT
1441        {return const_iterator(this, __get_pointer());}
1442    _LIBCPP_INLINE_VISIBILITY
1443    iterator end() _NOEXCEPT
1444        {return iterator(this, __get_pointer() + size());}
1445    _LIBCPP_INLINE_VISIBILITY
1446    const_iterator end() const _NOEXCEPT
1447        {return const_iterator(this, __get_pointer() + size());}
1448#else
1449    _LIBCPP_INLINE_VISIBILITY
1450    iterator begin() _NOEXCEPT
1451        {return iterator(__get_pointer());}
1452    _LIBCPP_INLINE_VISIBILITY
1453    const_iterator begin() const _NOEXCEPT
1454        {return const_iterator(__get_pointer());}
1455    _LIBCPP_INLINE_VISIBILITY
1456    iterator end() _NOEXCEPT
1457        {return iterator(__get_pointer() + size());}
1458    _LIBCPP_INLINE_VISIBILITY
1459    const_iterator end() const _NOEXCEPT
1460        {return const_iterator(__get_pointer() + size());}
1461#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1462    _LIBCPP_INLINE_VISIBILITY
1463    reverse_iterator rbegin() _NOEXCEPT
1464        {return reverse_iterator(end());}
1465    _LIBCPP_INLINE_VISIBILITY
1466    const_reverse_iterator rbegin() const _NOEXCEPT
1467        {return const_reverse_iterator(end());}
1468    _LIBCPP_INLINE_VISIBILITY
1469    reverse_iterator rend() _NOEXCEPT
1470        {return reverse_iterator(begin());}
1471    _LIBCPP_INLINE_VISIBILITY
1472    const_reverse_iterator rend() const _NOEXCEPT
1473        {return const_reverse_iterator(begin());}
1474
1475    _LIBCPP_INLINE_VISIBILITY
1476    const_iterator cbegin() const _NOEXCEPT
1477        {return begin();}
1478    _LIBCPP_INLINE_VISIBILITY
1479    const_iterator cend() const _NOEXCEPT
1480        {return end();}
1481    _LIBCPP_INLINE_VISIBILITY
1482    const_reverse_iterator crbegin() const _NOEXCEPT
1483        {return rbegin();}
1484    _LIBCPP_INLINE_VISIBILITY
1485    const_reverse_iterator crend() const _NOEXCEPT
1486        {return rend();}
1487
1488    _LIBCPP_INLINE_VISIBILITY size_type size() const _NOEXCEPT
1489        {return __is_long() ? __get_long_size() : __get_short_size();}
1490    _LIBCPP_INLINE_VISIBILITY size_type length() const _NOEXCEPT {return size();}
1491    _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT;
1492    _LIBCPP_INLINE_VISIBILITY size_type capacity() const _NOEXCEPT
1493        {return (__is_long() ? __get_long_cap()
1494                             : static_cast<size_type>(__min_cap)) - 1;}
1495
1496    void resize(size_type __n, value_type __c);
1497    _LIBCPP_INLINE_VISIBILITY void resize(size_type __n) {resize(__n, value_type());}
1498
1499    void reserve(size_type res_arg = 0);
1500    _LIBCPP_INLINE_VISIBILITY
1501    void shrink_to_fit() _NOEXCEPT {reserve();}
1502    _LIBCPP_INLINE_VISIBILITY
1503    void clear() _NOEXCEPT;
1504    _LIBCPP_INLINE_VISIBILITY bool empty() const _NOEXCEPT {return size() == 0;}
1505
1506    _LIBCPP_INLINE_VISIBILITY const_reference operator[](size_type __pos) const;
1507    _LIBCPP_INLINE_VISIBILITY reference       operator[](size_type __pos);
1508
1509    const_reference at(size_type __n) const;
1510    reference       at(size_type __n);
1511
1512    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(const basic_string& __str) {return append(__str);}
1513    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(const value_type* __s)         {return append(__s);}
1514    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(value_type __c)            {push_back(__c); return *this;}
1515#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1516    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(initializer_list<value_type> __il) {return append(__il);}
1517#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1518
1519    _LIBCPP_INLINE_VISIBILITY
1520    basic_string& append(const basic_string& __str);
1521    basic_string& append(const basic_string& __str, size_type __pos, size_type __n=npos);
1522    basic_string& append(const value_type* __s, size_type __n);
1523    basic_string& append(const value_type* __s);
1524    basic_string& append(size_type __n, value_type __c);
1525    template<class _InputIterator>
1526        typename enable_if
1527        <
1528            __is_exactly_input_iterator<_InputIterator>::value
1529                || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
1530            basic_string&
1531        >::type
1532        append(_InputIterator __first, _InputIterator __last);
1533    template<class _ForwardIterator>
1534        typename enable_if
1535        <
1536            __is_forward_iterator<_ForwardIterator>::value
1537                && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
1538            basic_string&
1539        >::type
1540        append(_ForwardIterator __first, _ForwardIterator __last);
1541#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1542    _LIBCPP_INLINE_VISIBILITY
1543    basic_string& append(initializer_list<value_type> __il) {return append(__il.begin(), __il.size());}
1544#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1545
1546    void push_back(value_type __c);
1547    _LIBCPP_INLINE_VISIBILITY
1548    void pop_back();
1549    _LIBCPP_INLINE_VISIBILITY reference       front();
1550    _LIBCPP_INLINE_VISIBILITY const_reference front() const;
1551    _LIBCPP_INLINE_VISIBILITY reference       back();
1552    _LIBCPP_INLINE_VISIBILITY const_reference back() const;
1553
1554    _LIBCPP_INLINE_VISIBILITY
1555    basic_string& assign(const basic_string& __str) { return *this = __str; }
1556#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1557    _LIBCPP_INLINE_VISIBILITY
1558    basic_string& assign(basic_string&& str)
1559        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
1560        {*this = _VSTD::move(str); return *this;}
1561#endif
1562    basic_string& assign(const basic_string& __str, size_type __pos, size_type __n=npos);
1563    basic_string& assign(const value_type* __s, size_type __n);
1564    basic_string& assign(const value_type* __s);
1565    basic_string& assign(size_type __n, value_type __c);
1566    template<class _InputIterator>
1567        typename enable_if
1568        <
1569           __is_exactly_input_iterator<_InputIterator>::value
1570                || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
1571            basic_string&
1572        >::type
1573        assign(_InputIterator __first, _InputIterator __last);
1574    template<class _ForwardIterator>
1575        typename enable_if
1576        <
1577            __is_forward_iterator<_ForwardIterator>::value
1578                 && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
1579            basic_string&
1580        >::type
1581        assign(_ForwardIterator __first, _ForwardIterator __last);
1582#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1583    _LIBCPP_INLINE_VISIBILITY
1584    basic_string& assign(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
1585#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1586
1587    _LIBCPP_INLINE_VISIBILITY
1588    basic_string& insert(size_type __pos1, const basic_string& __str);
1589    basic_string& insert(size_type __pos1, const basic_string& __str, size_type __pos2, size_type __n=npos);
1590    basic_string& insert(size_type __pos, const value_type* __s, size_type __n);
1591    basic_string& insert(size_type __pos, const value_type* __s);
1592    basic_string& insert(size_type __pos, size_type __n, value_type __c);
1593    iterator      insert(const_iterator __pos, value_type __c);
1594    _LIBCPP_INLINE_VISIBILITY
1595    iterator      insert(const_iterator __pos, size_type __n, value_type __c);
1596    template<class _InputIterator>
1597        typename enable_if
1598        <
1599           __is_exactly_input_iterator<_InputIterator>::value
1600                || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
1601            iterator
1602        >::type
1603        insert(const_iterator __pos, _InputIterator __first, _InputIterator __last);
1604    template<class _ForwardIterator>
1605        typename enable_if
1606        <
1607            __is_forward_iterator<_ForwardIterator>::value
1608                 && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
1609            iterator
1610        >::type
1611        insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last);
1612#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1613    _LIBCPP_INLINE_VISIBILITY
1614    iterator insert(const_iterator __pos, initializer_list<value_type> __il)
1615                    {return insert(__pos, __il.begin(), __il.end());}
1616#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1617
1618    basic_string& erase(size_type __pos = 0, size_type __n = npos);
1619    _LIBCPP_INLINE_VISIBILITY
1620    iterator      erase(const_iterator __pos);
1621    _LIBCPP_INLINE_VISIBILITY
1622    iterator      erase(const_iterator __first, const_iterator __last);
1623
1624    _LIBCPP_INLINE_VISIBILITY
1625    basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str);
1626    basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos);
1627    basic_string& replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2);
1628    basic_string& replace(size_type __pos, size_type __n1, const value_type* __s);
1629    basic_string& replace(size_type __pos, size_type __n1, size_type __n2, value_type __c);
1630    _LIBCPP_INLINE_VISIBILITY
1631    basic_string& replace(const_iterator __i1, const_iterator __i2, const basic_string& __str);
1632    _LIBCPP_INLINE_VISIBILITY
1633    basic_string& replace(const_iterator __i1, const_iterator __i2, const value_type* __s, size_type __n);
1634    _LIBCPP_INLINE_VISIBILITY
1635    basic_string& replace(const_iterator __i1, const_iterator __i2, const value_type* __s);
1636    _LIBCPP_INLINE_VISIBILITY
1637    basic_string& replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c);
1638    template<class _InputIterator>
1639        typename enable_if
1640        <
1641            __is_input_iterator<_InputIterator>::value,
1642            basic_string&
1643        >::type
1644        replace(const_iterator __i1, const_iterator __i2, _InputIterator __j1, _InputIterator __j2);
1645#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1646    _LIBCPP_INLINE_VISIBILITY
1647    basic_string& replace(const_iterator __i1, const_iterator __i2, initializer_list<value_type> __il)
1648        {return replace(__i1, __i2, __il.begin(), __il.end());}
1649#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
1650
1651    size_type copy(value_type* __s, size_type __n, size_type __pos = 0) const;
1652    _LIBCPP_INLINE_VISIBILITY
1653    basic_string substr(size_type __pos = 0, size_type __n = npos) const;
1654
1655    _LIBCPP_INLINE_VISIBILITY
1656    void swap(basic_string& __str)
1657#if _LIBCPP_STD_VER >= 14
1658        _NOEXCEPT;
1659#else
1660        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
1661                    __is_nothrow_swappable<allocator_type>::value);
1662#endif
1663
1664    _LIBCPP_INLINE_VISIBILITY
1665    const value_type* c_str() const _NOEXCEPT {return data();}
1666    _LIBCPP_INLINE_VISIBILITY
1667    const value_type* data() const _NOEXCEPT  {return _VSTD::__to_raw_pointer(__get_pointer());}
1668#if _LIBCPP_STD_VER > 14
1669    _LIBCPP_INLINE_VISIBILITY
1670    value_type* data()             _NOEXCEPT  {return _VSTD::__to_raw_pointer(__get_pointer());}
1671#endif
1672
1673    _LIBCPP_INLINE_VISIBILITY
1674    allocator_type get_allocator() const _NOEXCEPT {return __alloc();}
1675
1676    _LIBCPP_INLINE_VISIBILITY
1677    size_type find(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
1678    size_type find(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1679    _LIBCPP_INLINE_VISIBILITY
1680    size_type find(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
1681    size_type find(value_type __c, size_type __pos = 0) const _NOEXCEPT;
1682
1683    _LIBCPP_INLINE_VISIBILITY
1684    size_type rfind(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
1685    size_type rfind(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1686    _LIBCPP_INLINE_VISIBILITY
1687    size_type rfind(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
1688    size_type rfind(value_type __c, size_type __pos = npos) const _NOEXCEPT;
1689
1690    _LIBCPP_INLINE_VISIBILITY
1691    size_type find_first_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
1692    size_type find_first_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1693    _LIBCPP_INLINE_VISIBILITY
1694    size_type find_first_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
1695    _LIBCPP_INLINE_VISIBILITY
1696    size_type find_first_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
1697
1698    _LIBCPP_INLINE_VISIBILITY
1699    size_type find_last_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
1700    size_type find_last_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1701    _LIBCPP_INLINE_VISIBILITY
1702    size_type find_last_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
1703    _LIBCPP_INLINE_VISIBILITY
1704    size_type find_last_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
1705
1706    _LIBCPP_INLINE_VISIBILITY
1707    size_type find_first_not_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
1708    size_type find_first_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1709    _LIBCPP_INLINE_VISIBILITY
1710    size_type find_first_not_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
1711    _LIBCPP_INLINE_VISIBILITY
1712    size_type find_first_not_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
1713
1714    _LIBCPP_INLINE_VISIBILITY
1715    size_type find_last_not_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
1716    size_type find_last_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
1717    _LIBCPP_INLINE_VISIBILITY
1718    size_type find_last_not_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
1719    _LIBCPP_INLINE_VISIBILITY
1720    size_type find_last_not_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
1721
1722    _LIBCPP_INLINE_VISIBILITY
1723    int compare(const basic_string& __str) const _NOEXCEPT;
1724    _LIBCPP_INLINE_VISIBILITY
1725    int compare(size_type __pos1, size_type __n1, const basic_string& __str) const;
1726    int compare(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos) const;
1727    int compare(const value_type* __s) const _NOEXCEPT;
1728    int compare(size_type __pos1, size_type __n1, const value_type* __s) const;
1729    int compare(size_type __pos1, size_type __n1, const value_type* __s, size_type __n2) const;
1730
1731    _LIBCPP_INLINE_VISIBILITY bool __invariants() const;
1732
1733    _LIBCPP_INLINE_VISIBILITY
1734    bool __is_long() const _NOEXCEPT
1735        {return bool(__r_.first().__s.__size_ & __short_mask);}
1736
1737#if _LIBCPP_DEBUG_LEVEL >= 2
1738
1739    bool __dereferenceable(const const_iterator* __i) const;
1740    bool __decrementable(const const_iterator* __i) const;
1741    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
1742    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
1743
1744#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1745
1746private:
1747    _LIBCPP_INLINE_VISIBILITY
1748    allocator_type& __alloc() _NOEXCEPT
1749        {return __r_.second();}
1750    _LIBCPP_INLINE_VISIBILITY
1751    const allocator_type& __alloc() const _NOEXCEPT
1752        {return __r_.second();}
1753
1754#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1755
1756    _LIBCPP_INLINE_VISIBILITY
1757    void __set_short_size(size_type __s) _NOEXCEPT
1758#   if _LIBCPP_BIG_ENDIAN
1759        {__r_.first().__s.__size_ = (unsigned char)(__s << 1);}
1760#   else
1761        {__r_.first().__s.__size_ = (unsigned char)(__s);}
1762#   endif
1763
1764    _LIBCPP_INLINE_VISIBILITY
1765    size_type __get_short_size() const _NOEXCEPT
1766#   if _LIBCPP_BIG_ENDIAN
1767        {return __r_.first().__s.__size_ >> 1;}
1768#   else
1769        {return __r_.first().__s.__size_;}
1770#   endif
1771
1772#else  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1773
1774    _LIBCPP_INLINE_VISIBILITY
1775    void __set_short_size(size_type __s) _NOEXCEPT
1776#   if _LIBCPP_BIG_ENDIAN
1777        {__r_.first().__s.__size_ = (unsigned char)(__s);}
1778#   else
1779        {__r_.first().__s.__size_ = (unsigned char)(__s << 1);}
1780#   endif
1781
1782    _LIBCPP_INLINE_VISIBILITY
1783    size_type __get_short_size() const _NOEXCEPT
1784#   if _LIBCPP_BIG_ENDIAN
1785        {return __r_.first().__s.__size_;}
1786#   else
1787        {return __r_.first().__s.__size_ >> 1;}
1788#   endif
1789
1790#endif  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
1791
1792    _LIBCPP_INLINE_VISIBILITY
1793    void __set_long_size(size_type __s) _NOEXCEPT
1794        {__r_.first().__l.__size_ = __s;}
1795    _LIBCPP_INLINE_VISIBILITY
1796    size_type __get_long_size() const _NOEXCEPT
1797        {return __r_.first().__l.__size_;}
1798    _LIBCPP_INLINE_VISIBILITY
1799    void __set_size(size_type __s) _NOEXCEPT
1800        {if (__is_long()) __set_long_size(__s); else __set_short_size(__s);}
1801
1802    _LIBCPP_INLINE_VISIBILITY
1803    void __set_long_cap(size_type __s) _NOEXCEPT
1804        {__r_.first().__l.__cap_  = __long_mask | __s;}
1805    _LIBCPP_INLINE_VISIBILITY
1806    size_type __get_long_cap() const _NOEXCEPT
1807        {return __r_.first().__l.__cap_ & size_type(~__long_mask);}
1808
1809    _LIBCPP_INLINE_VISIBILITY
1810    void __set_long_pointer(pointer __p) _NOEXCEPT
1811        {__r_.first().__l.__data_ = __p;}
1812    _LIBCPP_INLINE_VISIBILITY
1813    pointer __get_long_pointer() _NOEXCEPT
1814        {return __r_.first().__l.__data_;}
1815    _LIBCPP_INLINE_VISIBILITY
1816    const_pointer __get_long_pointer() const _NOEXCEPT
1817        {return __r_.first().__l.__data_;}
1818    _LIBCPP_INLINE_VISIBILITY
1819    pointer __get_short_pointer() _NOEXCEPT
1820        {return pointer_traits<pointer>::pointer_to(__r_.first().__s.__data_[0]);}
1821    _LIBCPP_INLINE_VISIBILITY
1822    const_pointer __get_short_pointer() const _NOEXCEPT
1823        {return pointer_traits<const_pointer>::pointer_to(__r_.first().__s.__data_[0]);}
1824    _LIBCPP_INLINE_VISIBILITY
1825    pointer __get_pointer() _NOEXCEPT
1826        {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
1827    _LIBCPP_INLINE_VISIBILITY
1828    const_pointer __get_pointer() const _NOEXCEPT
1829        {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
1830
1831    _LIBCPP_INLINE_VISIBILITY
1832    void __zero() _NOEXCEPT
1833        {
1834            size_type (&__a)[__n_words] = __r_.first().__r.__words;
1835            for (unsigned __i = 0; __i < __n_words; ++__i)
1836                __a[__i] = 0;
1837        }
1838
1839    template <size_type __a> static
1840        _LIBCPP_INLINE_VISIBILITY
1841        size_type __align_it(size_type __s) _NOEXCEPT
1842            {return (__s + (__a-1)) & ~(__a-1);}
1843    enum {__alignment = 16};
1844    static _LIBCPP_INLINE_VISIBILITY
1845    size_type __recommend(size_type __s) _NOEXCEPT
1846        {return (__s < __min_cap ? static_cast<size_type>(__min_cap) :
1847                 __align_it<sizeof(value_type) < __alignment ?
1848                            __alignment/sizeof(value_type) : 1 > (__s+1)) - 1;}
1849
1850    void __init(const value_type* __s, size_type __sz, size_type __reserve);
1851    void __init(const value_type* __s, size_type __sz);
1852    void __init(size_type __n, value_type __c);
1853
1854    template <class _InputIterator>
1855    typename enable_if
1856    <
1857        __is_exactly_input_iterator<_InputIterator>::value,
1858        void
1859    >::type
1860    __init(_InputIterator __first, _InputIterator __last);
1861
1862    template <class _ForwardIterator>
1863    typename enable_if
1864    <
1865        __is_forward_iterator<_ForwardIterator>::value,
1866        void
1867    >::type
1868    __init(_ForwardIterator __first, _ForwardIterator __last);
1869
1870    void __grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
1871                   size_type __n_copy,  size_type __n_del,     size_type __n_add = 0);
1872    void __grow_by_and_replace(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
1873                               size_type __n_copy,  size_type __n_del,
1874                               size_type __n_add, const value_type* __p_new_stuff);
1875
1876    _LIBCPP_INLINE_VISIBILITY
1877    void __erase_to_end(size_type __pos);
1878
1879    _LIBCPP_INLINE_VISIBILITY
1880    void __copy_assign_alloc(const basic_string& __str)
1881        {__copy_assign_alloc(__str, integral_constant<bool,
1882                      __alloc_traits::propagate_on_container_copy_assignment::value>());}
1883
1884    _LIBCPP_INLINE_VISIBILITY
1885    void __copy_assign_alloc(const basic_string& __str, true_type)
1886        {
1887            if (__alloc() != __str.__alloc())
1888            {
1889                clear();
1890                shrink_to_fit();
1891            }
1892            __alloc() = __str.__alloc();
1893        }
1894
1895    _LIBCPP_INLINE_VISIBILITY
1896    void __copy_assign_alloc(const basic_string&, false_type) _NOEXCEPT
1897        {}
1898
1899#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
1900    _LIBCPP_INLINE_VISIBILITY
1901    void __move_assign(basic_string& __str, false_type)
1902        _NOEXCEPT_(__alloc_traits::is_always_equal::value);
1903    _LIBCPP_INLINE_VISIBILITY
1904    void __move_assign(basic_string& __str, true_type)
1905#if _LIBCPP_STD_VER > 14
1906        _NOEXCEPT;
1907#else
1908        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
1909#endif
1910#endif
1911
1912    _LIBCPP_INLINE_VISIBILITY
1913    void
1914    __move_assign_alloc(basic_string& __str)
1915        _NOEXCEPT_(
1916            !__alloc_traits::propagate_on_container_move_assignment::value ||
1917            is_nothrow_move_assignable<allocator_type>::value)
1918    {__move_assign_alloc(__str, integral_constant<bool,
1919                      __alloc_traits::propagate_on_container_move_assignment::value>());}
1920
1921    _LIBCPP_INLINE_VISIBILITY
1922    void __move_assign_alloc(basic_string& __c, true_type)
1923        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
1924        {
1925            __alloc() = _VSTD::move(__c.__alloc());
1926        }
1927
1928    _LIBCPP_INLINE_VISIBILITY
1929    void __move_assign_alloc(basic_string&, false_type)
1930        _NOEXCEPT
1931        {}
1932
1933    _LIBCPP_INLINE_VISIBILITY void __invalidate_all_iterators();
1934    _LIBCPP_INLINE_VISIBILITY void __invalidate_iterators_past(size_type);
1935
1936    friend basic_string operator+<>(const basic_string&, const basic_string&);
1937    friend basic_string operator+<>(const value_type*, const basic_string&);
1938    friend basic_string operator+<>(value_type, const basic_string&);
1939    friend basic_string operator+<>(const basic_string&, const value_type*);
1940    friend basic_string operator+<>(const basic_string&, value_type);
1941};
1942
1943template <class _CharT, class _Traits, class _Allocator>
1944inline _LIBCPP_INLINE_VISIBILITY
1945void
1946basic_string<_CharT, _Traits, _Allocator>::__invalidate_all_iterators()
1947{
1948#if _LIBCPP_DEBUG_LEVEL >= 2
1949    __get_db()->__invalidate_all(this);
1950#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1951}
1952
1953template <class _CharT, class _Traits, class _Allocator>
1954inline _LIBCPP_INLINE_VISIBILITY
1955void
1956basic_string<_CharT, _Traits, _Allocator>::__invalidate_iterators_past(size_type
1957#if _LIBCPP_DEBUG_LEVEL >= 2
1958                                                                        __pos
1959#endif
1960                                                                      )
1961{
1962#if _LIBCPP_DEBUG_LEVEL >= 2
1963    __c_node* __c = __get_db()->__find_c_and_lock(this);
1964    if (__c)
1965    {
1966        const_pointer __new_last = __get_pointer() + __pos;
1967        for (__i_node** __p = __c->end_; __p != __c->beg_; )
1968        {
1969            --__p;
1970            const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
1971            if (__i->base() > __new_last)
1972            {
1973                (*__p)->__c_ = nullptr;
1974                if (--__c->end_ != __p)
1975                    memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
1976            }
1977        }
1978        __get_db()->unlock();
1979    }
1980#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1981}
1982
1983template <class _CharT, class _Traits, class _Allocator>
1984inline _LIBCPP_INLINE_VISIBILITY
1985basic_string<_CharT, _Traits, _Allocator>::basic_string()
1986    _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
1987{
1988#if _LIBCPP_DEBUG_LEVEL >= 2
1989    __get_db()->__insert_c(this);
1990#endif
1991    __zero();
1992}
1993
1994template <class _CharT, class _Traits, class _Allocator>
1995inline _LIBCPP_INLINE_VISIBILITY
1996basic_string<_CharT, _Traits, _Allocator>::basic_string(const allocator_type& __a)
1997#if _LIBCPP_STD_VER <= 14
1998        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
1999#else
2000        _NOEXCEPT
2001#endif
2002: __r_(__a)
2003{
2004#if _LIBCPP_DEBUG_LEVEL >= 2
2005    __get_db()->__insert_c(this);
2006#endif
2007    __zero();
2008}
2009
2010template <class _CharT, class _Traits, class _Allocator>
2011void
2012basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz, size_type __reserve)
2013{
2014    if (__reserve > max_size())
2015        this->__throw_length_error();
2016    pointer __p;
2017    if (__reserve < __min_cap)
2018    {
2019        __set_short_size(__sz);
2020        __p = __get_short_pointer();
2021    }
2022    else
2023    {
2024        size_type __cap = __recommend(__reserve);
2025        __p = __alloc_traits::allocate(__alloc(), __cap+1);
2026        __set_long_pointer(__p);
2027        __set_long_cap(__cap+1);
2028        __set_long_size(__sz);
2029    }
2030    traits_type::copy(_VSTD::__to_raw_pointer(__p), __s, __sz);
2031    traits_type::assign(__p[__sz], value_type());
2032}
2033
2034template <class _CharT, class _Traits, class _Allocator>
2035void
2036basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz)
2037{
2038    if (__sz > max_size())
2039        this->__throw_length_error();
2040    pointer __p;
2041    if (__sz < __min_cap)
2042    {
2043        __set_short_size(__sz);
2044        __p = __get_short_pointer();
2045    }
2046    else
2047    {
2048        size_type __cap = __recommend(__sz);
2049        __p = __alloc_traits::allocate(__alloc(), __cap+1);
2050        __set_long_pointer(__p);
2051        __set_long_cap(__cap+1);
2052        __set_long_size(__sz);
2053    }
2054    traits_type::copy(_VSTD::__to_raw_pointer(__p), __s, __sz);
2055    traits_type::assign(__p[__sz], value_type());
2056}
2057
2058template <class _CharT, class _Traits, class _Allocator>
2059inline _LIBCPP_INLINE_VISIBILITY
2060basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s)
2061{
2062    _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*) detected nullptr");
2063    __init(__s, traits_type::length(__s));
2064#if _LIBCPP_DEBUG_LEVEL >= 2
2065    __get_db()->__insert_c(this);
2066#endif
2067}
2068
2069template <class _CharT, class _Traits, class _Allocator>
2070inline _LIBCPP_INLINE_VISIBILITY
2071basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s, const allocator_type& __a)
2072    : __r_(__a)
2073{
2074    _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*, allocator) detected nullptr");
2075    __init(__s, traits_type::length(__s));
2076#if _LIBCPP_DEBUG_LEVEL >= 2
2077    __get_db()->__insert_c(this);
2078#endif
2079}
2080
2081template <class _CharT, class _Traits, class _Allocator>
2082inline _LIBCPP_INLINE_VISIBILITY
2083basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s, size_type __n)
2084{
2085    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n) detected nullptr");
2086    __init(__s, __n);
2087#if _LIBCPP_DEBUG_LEVEL >= 2
2088    __get_db()->__insert_c(this);
2089#endif
2090}
2091
2092template <class _CharT, class _Traits, class _Allocator>
2093inline _LIBCPP_INLINE_VISIBILITY
2094basic_string<_CharT, _Traits, _Allocator>::basic_string(const value_type* __s, size_type __n, const allocator_type& __a)
2095    : __r_(__a)
2096{
2097    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n, allocator) detected nullptr");
2098    __init(__s, __n);
2099#if _LIBCPP_DEBUG_LEVEL >= 2
2100    __get_db()->__insert_c(this);
2101#endif
2102}
2103
2104template <class _CharT, class _Traits, class _Allocator>
2105basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str)
2106    : __r_(__alloc_traits::select_on_container_copy_construction(__str.__alloc()))
2107{
2108    if (!__str.__is_long())
2109        __r_.first().__r = __str.__r_.first().__r;
2110    else
2111        __init(_VSTD::__to_raw_pointer(__str.__get_long_pointer()), __str.__get_long_size());
2112#if _LIBCPP_DEBUG_LEVEL >= 2
2113    __get_db()->__insert_c(this);
2114#endif
2115}
2116
2117template <class _CharT, class _Traits, class _Allocator>
2118basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str, const allocator_type& __a)
2119    : __r_(__a)
2120{
2121    if (!__str.__is_long())
2122        __r_.first().__r = __str.__r_.first().__r;
2123    else
2124        __init(_VSTD::__to_raw_pointer(__str.__get_long_pointer()), __str.__get_long_size());
2125#if _LIBCPP_DEBUG_LEVEL >= 2
2126    __get_db()->__insert_c(this);
2127#endif
2128}
2129
2130#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2131
2132template <class _CharT, class _Traits, class _Allocator>
2133inline _LIBCPP_INLINE_VISIBILITY
2134basic_string<_CharT, _Traits, _Allocator>::basic_string(basic_string&& __str)
2135#if _LIBCPP_STD_VER <= 14
2136        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
2137#else
2138        _NOEXCEPT
2139#endif
2140    : __r_(_VSTD::move(__str.__r_))
2141{
2142    __str.__zero();
2143#if _LIBCPP_DEBUG_LEVEL >= 2
2144    __get_db()->__insert_c(this);
2145    if (__is_long())
2146        __get_db()->swap(this, &__str);
2147#endif
2148}
2149
2150template <class _CharT, class _Traits, class _Allocator>
2151inline _LIBCPP_INLINE_VISIBILITY
2152basic_string<_CharT, _Traits, _Allocator>::basic_string(basic_string&& __str, const allocator_type& __a)
2153    : __r_(__a)
2154{
2155    if (__str.__is_long() && __a != __str.__alloc()) // copy, not move
2156        __init(_VSTD::__to_raw_pointer(__str.__get_long_pointer()), __str.__get_long_size());
2157    else
2158    {
2159        __r_.first().__r = __str.__r_.first().__r;
2160        __str.__zero();
2161    }
2162#if _LIBCPP_DEBUG_LEVEL >= 2
2163    __get_db()->__insert_c(this);
2164    if (__is_long())
2165        __get_db()->swap(this, &__str);
2166#endif
2167}
2168
2169#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
2170
2171template <class _CharT, class _Traits, class _Allocator>
2172void
2173basic_string<_CharT, _Traits, _Allocator>::__init(size_type __n, value_type __c)
2174{
2175    if (__n > max_size())
2176        this->__throw_length_error();
2177    pointer __p;
2178    if (__n < __min_cap)
2179    {
2180        __set_short_size(__n);
2181        __p = __get_short_pointer();
2182    }
2183    else
2184    {
2185        size_type __cap = __recommend(__n);
2186        __p = __alloc_traits::allocate(__alloc(), __cap+1);
2187        __set_long_pointer(__p);
2188        __set_long_cap(__cap+1);
2189        __set_long_size(__n);
2190    }
2191    traits_type::assign(_VSTD::__to_raw_pointer(__p), __n, __c);
2192    traits_type::assign(__p[__n], value_type());
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)
2198{
2199    __init(__n, __c);
2200#if _LIBCPP_DEBUG_LEVEL >= 2
2201    __get_db()->__insert_c(this);
2202#endif
2203}
2204
2205template <class _CharT, class _Traits, class _Allocator>
2206inline _LIBCPP_INLINE_VISIBILITY
2207basic_string<_CharT, _Traits, _Allocator>::basic_string(size_type __n, value_type __c, const allocator_type& __a)
2208    : __r_(__a)
2209{
2210    __init(__n, __c);
2211#if _LIBCPP_DEBUG_LEVEL >= 2
2212    __get_db()->__insert_c(this);
2213#endif
2214}
2215
2216template <class _CharT, class _Traits, class _Allocator>
2217basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str, size_type __pos, size_type __n,
2218                                                        const allocator_type& __a)
2219    : __r_(__a)
2220{
2221    size_type __str_sz = __str.size();
2222    if (__pos > __str_sz)
2223        this->__throw_out_of_range();
2224    __init(__str.data() + __pos, _VSTD::min(__n, __str_sz - __pos));
2225#if _LIBCPP_DEBUG_LEVEL >= 2
2226    __get_db()->__insert_c(this);
2227#endif
2228}
2229
2230template <class _CharT, class _Traits, class _Allocator>
2231inline _LIBCPP_INLINE_VISIBILITY
2232basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str, size_type __pos,
2233                                                        const allocator_type& __a)
2234    : __r_(__a)
2235{
2236    size_type __str_sz = __str.size();
2237    if (__pos > __str_sz)
2238        this->__throw_out_of_range();
2239    __init(__str.data() + __pos, __str_sz - __pos);
2240#if _LIBCPP_DEBUG_LEVEL >= 2
2241    __get_db()->__insert_c(this);
2242#endif
2243}
2244
2245template <class _CharT, class _Traits, class _Allocator>
2246template <class _InputIterator>
2247typename enable_if
2248<
2249    __is_exactly_input_iterator<_InputIterator>::value,
2250    void
2251>::type
2252basic_string<_CharT, _Traits, _Allocator>::__init(_InputIterator __first, _InputIterator __last)
2253{
2254    __zero();
2255#ifndef _LIBCPP_NO_EXCEPTIONS
2256    try
2257    {
2258#endif  // _LIBCPP_NO_EXCEPTIONS
2259    for (; __first != __last; ++__first)
2260        push_back(*__first);
2261#ifndef _LIBCPP_NO_EXCEPTIONS
2262    }
2263    catch (...)
2264    {
2265        if (__is_long())
2266            __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
2267        throw;
2268    }
2269#endif  // _LIBCPP_NO_EXCEPTIONS
2270}
2271
2272template <class _CharT, class _Traits, class _Allocator>
2273template <class _ForwardIterator>
2274typename enable_if
2275<
2276    __is_forward_iterator<_ForwardIterator>::value,
2277    void
2278>::type
2279basic_string<_CharT, _Traits, _Allocator>::__init(_ForwardIterator __first, _ForwardIterator __last)
2280{
2281    size_type __sz = static_cast<size_type>(_VSTD::distance(__first, __last));
2282    if (__sz > max_size())
2283        this->__throw_length_error();
2284    pointer __p;
2285    if (__sz < __min_cap)
2286    {
2287        __set_short_size(__sz);
2288        __p = __get_short_pointer();
2289    }
2290    else
2291    {
2292        size_type __cap = __recommend(__sz);
2293        __p = __alloc_traits::allocate(__alloc(), __cap+1);
2294        __set_long_pointer(__p);
2295        __set_long_cap(__cap+1);
2296        __set_long_size(__sz);
2297    }
2298    for (; __first != __last; ++__first, (void) ++__p)
2299        traits_type::assign(*__p, *__first);
2300    traits_type::assign(*__p, value_type());
2301}
2302
2303template <class _CharT, class _Traits, class _Allocator>
2304template<class _InputIterator>
2305inline _LIBCPP_INLINE_VISIBILITY
2306basic_string<_CharT, _Traits, _Allocator>::basic_string(_InputIterator __first, _InputIterator __last)
2307{
2308    __init(__first, __last);
2309#if _LIBCPP_DEBUG_LEVEL >= 2
2310    __get_db()->__insert_c(this);
2311#endif
2312}
2313
2314template <class _CharT, class _Traits, class _Allocator>
2315template<class _InputIterator>
2316inline _LIBCPP_INLINE_VISIBILITY
2317basic_string<_CharT, _Traits, _Allocator>::basic_string(_InputIterator __first, _InputIterator __last,
2318                                                        const allocator_type& __a)
2319    : __r_(__a)
2320{
2321    __init(__first, __last);
2322#if _LIBCPP_DEBUG_LEVEL >= 2
2323    __get_db()->__insert_c(this);
2324#endif
2325}
2326
2327#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2328
2329template <class _CharT, class _Traits, class _Allocator>
2330inline _LIBCPP_INLINE_VISIBILITY
2331basic_string<_CharT, _Traits, _Allocator>::basic_string(initializer_list<value_type> __il)
2332{
2333    __init(__il.begin(), __il.end());
2334#if _LIBCPP_DEBUG_LEVEL >= 2
2335    __get_db()->__insert_c(this);
2336#endif
2337}
2338
2339template <class _CharT, class _Traits, class _Allocator>
2340inline _LIBCPP_INLINE_VISIBILITY
2341basic_string<_CharT, _Traits, _Allocator>::basic_string(initializer_list<value_type> __il, const allocator_type& __a)
2342    : __r_(__a)
2343{
2344    __init(__il.begin(), __il.end());
2345#if _LIBCPP_DEBUG_LEVEL >= 2
2346    __get_db()->__insert_c(this);
2347#endif
2348}
2349
2350#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2351
2352template <class _CharT, class _Traits, class _Allocator>
2353basic_string<_CharT, _Traits, _Allocator>::~basic_string()
2354{
2355#if _LIBCPP_DEBUG_LEVEL >= 2
2356    __get_db()->__erase_c(this);
2357#endif
2358    if (__is_long())
2359        __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
2360}
2361
2362template <class _CharT, class _Traits, class _Allocator>
2363void
2364basic_string<_CharT, _Traits, _Allocator>::__grow_by_and_replace
2365    (size_type __old_cap, size_type __delta_cap, size_type __old_sz,
2366     size_type __n_copy,  size_type __n_del,     size_type __n_add, const value_type* __p_new_stuff)
2367{
2368    size_type __ms = max_size();
2369    if (__delta_cap > __ms - __old_cap - 1)
2370        this->__throw_length_error();
2371    pointer __old_p = __get_pointer();
2372    size_type __cap = __old_cap < __ms / 2 - __alignment ?
2373                          __recommend(_VSTD::max(__old_cap + __delta_cap, 2 * __old_cap)) :
2374                          __ms - 1;
2375    pointer __p = __alloc_traits::allocate(__alloc(), __cap+1);
2376    __invalidate_all_iterators();
2377    if (__n_copy != 0)
2378        traits_type::copy(_VSTD::__to_raw_pointer(__p),
2379                          _VSTD::__to_raw_pointer(__old_p), __n_copy);
2380    if (__n_add != 0)
2381        traits_type::copy(_VSTD::__to_raw_pointer(__p) + __n_copy, __p_new_stuff, __n_add);
2382    size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
2383    if (__sec_cp_sz != 0)
2384        traits_type::copy(_VSTD::__to_raw_pointer(__p) + __n_copy + __n_add,
2385                          _VSTD::__to_raw_pointer(__old_p) + __n_copy + __n_del, __sec_cp_sz);
2386    if (__old_cap+1 != __min_cap)
2387        __alloc_traits::deallocate(__alloc(), __old_p, __old_cap+1);
2388    __set_long_pointer(__p);
2389    __set_long_cap(__cap+1);
2390    __old_sz = __n_copy + __n_add + __sec_cp_sz;
2391    __set_long_size(__old_sz);
2392    traits_type::assign(__p[__old_sz], value_type());
2393}
2394
2395template <class _CharT, class _Traits, class _Allocator>
2396void
2397basic_string<_CharT, _Traits, _Allocator>::__grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
2398                                                     size_type __n_copy,  size_type __n_del,     size_type __n_add)
2399{
2400    size_type __ms = max_size();
2401    if (__delta_cap > __ms - __old_cap)
2402        this->__throw_length_error();
2403    pointer __old_p = __get_pointer();
2404    size_type __cap = __old_cap < __ms / 2 - __alignment ?
2405                          __recommend(_VSTD::max(__old_cap + __delta_cap, 2 * __old_cap)) :
2406                          __ms - 1;
2407    pointer __p = __alloc_traits::allocate(__alloc(), __cap+1);
2408    __invalidate_all_iterators();
2409    if (__n_copy != 0)
2410        traits_type::copy(_VSTD::__to_raw_pointer(__p),
2411                          _VSTD::__to_raw_pointer(__old_p), __n_copy);
2412    size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
2413    if (__sec_cp_sz != 0)
2414        traits_type::copy(_VSTD::__to_raw_pointer(__p) + __n_copy + __n_add,
2415                          _VSTD::__to_raw_pointer(__old_p) + __n_copy + __n_del,
2416                          __sec_cp_sz);
2417    if (__old_cap+1 != __min_cap)
2418        __alloc_traits::deallocate(__alloc(), __old_p, __old_cap+1);
2419    __set_long_pointer(__p);
2420    __set_long_cap(__cap+1);
2421}
2422
2423// assign
2424
2425template <class _CharT, class _Traits, class _Allocator>
2426basic_string<_CharT, _Traits, _Allocator>&
2427basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s, size_type __n)
2428{
2429    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::assign received nullptr");
2430    size_type __cap = capacity();
2431    if (__cap >= __n)
2432    {
2433        value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2434        traits_type::move(__p, __s, __n);
2435        traits_type::assign(__p[__n], value_type());
2436        __set_size(__n);
2437        __invalidate_iterators_past(__n);
2438    }
2439    else
2440    {
2441        size_type __sz = size();
2442        __grow_by_and_replace(__cap, __n - __cap, __sz, 0, __sz, __n, __s);
2443    }
2444    return *this;
2445}
2446
2447template <class _CharT, class _Traits, class _Allocator>
2448basic_string<_CharT, _Traits, _Allocator>&
2449basic_string<_CharT, _Traits, _Allocator>::assign(size_type __n, value_type __c)
2450{
2451    size_type __cap = capacity();
2452    if (__cap < __n)
2453    {
2454        size_type __sz = size();
2455        __grow_by(__cap, __n - __cap, __sz, 0, __sz);
2456    }
2457    else
2458        __invalidate_iterators_past(__n);
2459    value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2460    traits_type::assign(__p, __n, __c);
2461    traits_type::assign(__p[__n], value_type());
2462    __set_size(__n);
2463    return *this;
2464}
2465
2466template <class _CharT, class _Traits, class _Allocator>
2467basic_string<_CharT, _Traits, _Allocator>&
2468basic_string<_CharT, _Traits, _Allocator>::operator=(value_type __c)
2469{
2470    pointer __p;
2471    if (__is_long())
2472    {
2473        __p = __get_long_pointer();
2474        __set_long_size(1);
2475    }
2476    else
2477    {
2478        __p = __get_short_pointer();
2479        __set_short_size(1);
2480    }
2481    traits_type::assign(*__p, __c);
2482    traits_type::assign(*++__p, value_type());
2483    __invalidate_iterators_past(1);
2484    return *this;
2485}
2486
2487template <class _CharT, class _Traits, class _Allocator>
2488basic_string<_CharT, _Traits, _Allocator>&
2489basic_string<_CharT, _Traits, _Allocator>::operator=(const basic_string& __str)
2490{
2491    if (this != &__str)
2492    {
2493        __copy_assign_alloc(__str);
2494        assign(__str.data(), __str.size());
2495    }
2496    return *this;
2497}
2498
2499#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
2500
2501template <class _CharT, class _Traits, class _Allocator>
2502inline _LIBCPP_INLINE_VISIBILITY
2503void
2504basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, false_type)
2505    _NOEXCEPT_(__alloc_traits::is_always_equal::value)
2506{
2507    if (__alloc() != __str.__alloc())
2508        assign(__str);
2509    else
2510        __move_assign(__str, true_type());
2511}
2512
2513template <class _CharT, class _Traits, class _Allocator>
2514inline _LIBCPP_INLINE_VISIBILITY
2515void
2516basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, true_type)
2517#if _LIBCPP_STD_VER > 14
2518    _NOEXCEPT
2519#else
2520    _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
2521#endif
2522{
2523    clear();
2524    shrink_to_fit();
2525    __r_.first() = __str.__r_.first();
2526    __move_assign_alloc(__str);
2527    __str.__zero();
2528}
2529
2530template <class _CharT, class _Traits, class _Allocator>
2531inline _LIBCPP_INLINE_VISIBILITY
2532basic_string<_CharT, _Traits, _Allocator>&
2533basic_string<_CharT, _Traits, _Allocator>::operator=(basic_string&& __str)
2534    _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
2535{
2536    __move_assign(__str, integral_constant<bool,
2537          __alloc_traits::propagate_on_container_move_assignment::value>());
2538    return *this;
2539}
2540
2541#endif
2542
2543template <class _CharT, class _Traits, class _Allocator>
2544template<class _InputIterator>
2545typename enable_if
2546<
2547     __is_exactly_input_iterator <_InputIterator>::value
2548          || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
2549    basic_string<_CharT, _Traits, _Allocator>&
2550>::type
2551basic_string<_CharT, _Traits, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
2552{
2553    basic_string __temp(__first, __last, __alloc());
2554    assign(__temp.data(), __temp.size());
2555    return *this;
2556}
2557
2558template <class _CharT, class _Traits, class _Allocator>
2559template<class _ForwardIterator>
2560typename enable_if
2561<
2562    __is_forward_iterator<_ForwardIterator>::value
2563         && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
2564    basic_string<_CharT, _Traits, _Allocator>&
2565>::type
2566basic_string<_CharT, _Traits, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
2567{
2568    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
2569    size_type __cap = capacity();
2570    if (__cap < __n)
2571    {
2572        size_type __sz = size();
2573        __grow_by(__cap, __n - __cap, __sz, 0, __sz);
2574    }
2575    else
2576        __invalidate_iterators_past(__n);
2577    pointer __p = __get_pointer();
2578    for (; __first != __last; ++__first, ++__p)
2579        traits_type::assign(*__p, *__first);
2580    traits_type::assign(*__p, value_type());
2581    __set_size(__n);
2582    return *this;
2583}
2584
2585template <class _CharT, class _Traits, class _Allocator>
2586basic_string<_CharT, _Traits, _Allocator>&
2587basic_string<_CharT, _Traits, _Allocator>::assign(const basic_string& __str, size_type __pos, size_type __n)
2588{
2589    size_type __sz = __str.size();
2590    if (__pos > __sz)
2591        this->__throw_out_of_range();
2592    return assign(__str.data() + __pos, _VSTD::min(__n, __sz - __pos));
2593}
2594
2595template <class _CharT, class _Traits, class _Allocator>
2596basic_string<_CharT, _Traits, _Allocator>&
2597basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s)
2598{
2599    _LIBCPP_ASSERT(__s != nullptr, "string::assign received nullptr");
2600    return assign(__s, traits_type::length(__s));
2601}
2602
2603// append
2604
2605template <class _CharT, class _Traits, class _Allocator>
2606basic_string<_CharT, _Traits, _Allocator>&
2607basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s, size_type __n)
2608{
2609    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::append received nullptr");
2610    size_type __cap = capacity();
2611    size_type __sz = size();
2612    if (__cap - __sz >= __n)
2613    {
2614        if (__n)
2615        {
2616            value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2617            traits_type::copy(__p + __sz, __s, __n);
2618            __sz += __n;
2619            __set_size(__sz);
2620            traits_type::assign(__p[__sz], value_type());
2621        }
2622    }
2623    else
2624        __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __sz, 0, __n, __s);
2625    return *this;
2626}
2627
2628template <class _CharT, class _Traits, class _Allocator>
2629basic_string<_CharT, _Traits, _Allocator>&
2630basic_string<_CharT, _Traits, _Allocator>::append(size_type __n, value_type __c)
2631{
2632    if (__n)
2633    {
2634        size_type __cap = capacity();
2635        size_type __sz = size();
2636        if (__cap - __sz < __n)
2637            __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
2638        pointer __p = __get_pointer();
2639        traits_type::assign(_VSTD::__to_raw_pointer(__p) + __sz, __n, __c);
2640        __sz += __n;
2641        __set_size(__sz);
2642        traits_type::assign(__p[__sz], value_type());
2643    }
2644    return *this;
2645}
2646
2647template <class _CharT, class _Traits, class _Allocator>
2648void
2649basic_string<_CharT, _Traits, _Allocator>::push_back(value_type __c)
2650{
2651    bool __is_short = !__is_long();
2652    size_type __cap;
2653    size_type __sz;
2654    if (__is_short)
2655    {
2656        __cap = __min_cap - 1;
2657        __sz = __get_short_size();
2658    }
2659    else
2660    {
2661        __cap = __get_long_cap() - 1;
2662        __sz = __get_long_size();
2663    }
2664    if (__sz == __cap)
2665    {
2666        __grow_by(__cap, 1, __sz, __sz, 0);
2667        __is_short = !__is_long();
2668    }
2669    pointer __p;
2670    if (__is_short)
2671    {
2672        __p = __get_short_pointer() + __sz;
2673        __set_short_size(__sz+1);
2674    }
2675    else
2676    {
2677        __p = __get_long_pointer() + __sz;
2678        __set_long_size(__sz+1);
2679    }
2680    traits_type::assign(*__p, __c);
2681    traits_type::assign(*++__p, value_type());
2682}
2683
2684template <class _CharT, class _Traits, class _Allocator>
2685template<class _InputIterator>
2686typename enable_if
2687<
2688    __is_exactly_input_iterator<_InputIterator>::value
2689             || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
2690    basic_string<_CharT, _Traits, _Allocator>&
2691>::type
2692basic_string<_CharT, _Traits, _Allocator>::append(_InputIterator __first, _InputIterator __last)
2693{
2694	basic_string __temp (__first, __last, __alloc());
2695	append(__temp.data(), __temp.size());
2696    return *this;
2697}
2698
2699template <class _CharT, class _Traits, class _Allocator>
2700template<class _ForwardIterator>
2701typename enable_if
2702<
2703    __is_forward_iterator<_ForwardIterator>::value
2704          && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
2705    basic_string<_CharT, _Traits, _Allocator>&
2706>::type
2707basic_string<_CharT, _Traits, _Allocator>::append(_ForwardIterator __first, _ForwardIterator __last)
2708{
2709    size_type __sz = size();
2710    size_type __cap = capacity();
2711    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
2712    if (__n)
2713    {
2714        if (__cap - __sz < __n)
2715            __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
2716        pointer __p = __get_pointer() + __sz;
2717        for (; __first != __last; ++__p, ++__first)
2718            traits_type::assign(*__p, *__first);
2719        traits_type::assign(*__p, value_type());
2720        __set_size(__sz + __n);
2721    }
2722    return *this;
2723}
2724
2725template <class _CharT, class _Traits, class _Allocator>
2726inline _LIBCPP_INLINE_VISIBILITY
2727basic_string<_CharT, _Traits, _Allocator>&
2728basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str)
2729{
2730    return append(__str.data(), __str.size());
2731}
2732
2733template <class _CharT, class _Traits, class _Allocator>
2734basic_string<_CharT, _Traits, _Allocator>&
2735basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str, size_type __pos, size_type __n)
2736{
2737    size_type __sz = __str.size();
2738    if (__pos > __sz)
2739        this->__throw_out_of_range();
2740    return append(__str.data() + __pos, _VSTD::min(__n, __sz - __pos));
2741}
2742
2743template <class _CharT, class _Traits, class _Allocator>
2744basic_string<_CharT, _Traits, _Allocator>&
2745basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s)
2746{
2747    _LIBCPP_ASSERT(__s != nullptr, "string::append received nullptr");
2748    return append(__s, traits_type::length(__s));
2749}
2750
2751// insert
2752
2753template <class _CharT, class _Traits, class _Allocator>
2754basic_string<_CharT, _Traits, _Allocator>&
2755basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s, size_type __n)
2756{
2757    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::insert received nullptr");
2758    size_type __sz = size();
2759    if (__pos > __sz)
2760        this->__throw_out_of_range();
2761    size_type __cap = capacity();
2762    if (__cap - __sz >= __n)
2763    {
2764        if (__n)
2765        {
2766            value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2767            size_type __n_move = __sz - __pos;
2768            if (__n_move != 0)
2769            {
2770                if (__p + __pos <= __s && __s < __p + __sz)
2771                    __s += __n;
2772                traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
2773            }
2774            traits_type::move(__p + __pos, __s, __n);
2775            __sz += __n;
2776            __set_size(__sz);
2777            traits_type::assign(__p[__sz], value_type());
2778        }
2779    }
2780    else
2781        __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __pos, 0, __n, __s);
2782    return *this;
2783}
2784
2785template <class _CharT, class _Traits, class _Allocator>
2786basic_string<_CharT, _Traits, _Allocator>&
2787basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, size_type __n, value_type __c)
2788{
2789    size_type __sz = size();
2790    if (__pos > __sz)
2791        this->__throw_out_of_range();
2792    if (__n)
2793    {
2794        size_type __cap = capacity();
2795        value_type* __p;
2796        if (__cap - __sz >= __n)
2797        {
2798            __p = _VSTD::__to_raw_pointer(__get_pointer());
2799            size_type __n_move = __sz - __pos;
2800            if (__n_move != 0)
2801                traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
2802        }
2803        else
2804        {
2805            __grow_by(__cap, __sz + __n - __cap, __sz, __pos, 0, __n);
2806            __p = _VSTD::__to_raw_pointer(__get_long_pointer());
2807        }
2808        traits_type::assign(__p + __pos, __n, __c);
2809        __sz += __n;
2810        __set_size(__sz);
2811        traits_type::assign(__p[__sz], value_type());
2812    }
2813    return *this;
2814}
2815
2816template <class _CharT, class _Traits, class _Allocator>
2817template<class _InputIterator>
2818typename enable_if
2819<
2820   __is_exactly_input_iterator<_InputIterator>::value
2821        || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value,
2822   typename basic_string<_CharT, _Traits, _Allocator>::iterator
2823>::type
2824basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _InputIterator __first, _InputIterator __last)
2825{
2826#if _LIBCPP_DEBUG_LEVEL >= 2
2827    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
2828        "string::insert(iterator, range) called with an iterator not"
2829        " referring to this string");
2830#endif
2831    basic_string __temp(__first, __last, __alloc());
2832    return insert(__pos, __temp.data(), __temp.data() + __temp.size());
2833}
2834
2835template <class _CharT, class _Traits, class _Allocator>
2836template<class _ForwardIterator>
2837typename enable_if
2838<
2839    __is_forward_iterator<_ForwardIterator>::value
2840        && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value,
2841    typename basic_string<_CharT, _Traits, _Allocator>::iterator
2842>::type
2843basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last)
2844{
2845#if _LIBCPP_DEBUG_LEVEL >= 2
2846    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
2847        "string::insert(iterator, range) called with an iterator not"
2848        " referring to this string");
2849#endif
2850    size_type __ip = static_cast<size_type>(__pos - begin());
2851    size_type __sz = size();
2852    size_type __cap = capacity();
2853    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
2854    if (__n)
2855    {
2856        value_type* __p;
2857        if (__cap - __sz >= __n)
2858        {
2859            __p = _VSTD::__to_raw_pointer(__get_pointer());
2860            size_type __n_move = __sz - __ip;
2861            if (__n_move != 0)
2862                traits_type::move(__p + __ip + __n, __p + __ip, __n_move);
2863        }
2864        else
2865        {
2866            __grow_by(__cap, __sz + __n - __cap, __sz, __ip, 0, __n);
2867            __p = _VSTD::__to_raw_pointer(__get_long_pointer());
2868        }
2869        __sz += __n;
2870        __set_size(__sz);
2871        traits_type::assign(__p[__sz], value_type());
2872        for (__p += __ip; __first != __last; ++__p, ++__first)
2873            traits_type::assign(*__p, *__first);
2874    }
2875    return begin() + __ip;
2876}
2877
2878template <class _CharT, class _Traits, class _Allocator>
2879inline _LIBCPP_INLINE_VISIBILITY
2880basic_string<_CharT, _Traits, _Allocator>&
2881basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str)
2882{
2883    return insert(__pos1, __str.data(), __str.size());
2884}
2885
2886template <class _CharT, class _Traits, class _Allocator>
2887basic_string<_CharT, _Traits, _Allocator>&
2888basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str,
2889                                                  size_type __pos2, size_type __n)
2890{
2891    size_type __str_sz = __str.size();
2892    if (__pos2 > __str_sz)
2893        this->__throw_out_of_range();
2894    return insert(__pos1, __str.data() + __pos2, _VSTD::min(__n, __str_sz - __pos2));
2895}
2896
2897template <class _CharT, class _Traits, class _Allocator>
2898basic_string<_CharT, _Traits, _Allocator>&
2899basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s)
2900{
2901    _LIBCPP_ASSERT(__s != nullptr, "string::insert received nullptr");
2902    return insert(__pos, __s, traits_type::length(__s));
2903}
2904
2905template <class _CharT, class _Traits, class _Allocator>
2906typename basic_string<_CharT, _Traits, _Allocator>::iterator
2907basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, value_type __c)
2908{
2909    size_type __ip = static_cast<size_type>(__pos - begin());
2910    size_type __sz = size();
2911    size_type __cap = capacity();
2912    value_type* __p;
2913    if (__cap == __sz)
2914    {
2915        __grow_by(__cap, 1, __sz, __ip, 0, 1);
2916        __p = _VSTD::__to_raw_pointer(__get_long_pointer());
2917    }
2918    else
2919    {
2920        __p = _VSTD::__to_raw_pointer(__get_pointer());
2921        size_type __n_move = __sz - __ip;
2922        if (__n_move != 0)
2923            traits_type::move(__p + __ip + 1, __p + __ip, __n_move);
2924    }
2925    traits_type::assign(__p[__ip], __c);
2926    traits_type::assign(__p[++__sz], value_type());
2927    __set_size(__sz);
2928    return begin() + static_cast<difference_type>(__ip);
2929}
2930
2931template <class _CharT, class _Traits, class _Allocator>
2932inline _LIBCPP_INLINE_VISIBILITY
2933typename basic_string<_CharT, _Traits, _Allocator>::iterator
2934basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, size_type __n, value_type __c)
2935{
2936#if _LIBCPP_DEBUG_LEVEL >= 2
2937    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
2938        "string::insert(iterator, n, value) called with an iterator not"
2939        " referring to this string");
2940#endif
2941    difference_type __p = __pos - begin();
2942    insert(static_cast<size_type>(__p), __n, __c);
2943    return begin() + __p;
2944}
2945
2946// replace
2947
2948template <class _CharT, class _Traits, class _Allocator>
2949basic_string<_CharT, _Traits, _Allocator>&
2950basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2)
2951{
2952    _LIBCPP_ASSERT(__n2 == 0 || __s != nullptr, "string::replace received nullptr");
2953    size_type __sz = size();
2954    if (__pos > __sz)
2955        this->__throw_out_of_range();
2956    __n1 = _VSTD::min(__n1, __sz - __pos);
2957    size_type __cap = capacity();
2958    if (__cap - __sz + __n1 >= __n2)
2959    {
2960        value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
2961        if (__n1 != __n2)
2962        {
2963            size_type __n_move = __sz - __pos - __n1;
2964            if (__n_move != 0)
2965            {
2966                if (__n1 > __n2)
2967                {
2968                    traits_type::move(__p + __pos, __s, __n2);
2969                    traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
2970                    goto __finish;
2971                }
2972                if (__p + __pos < __s && __s < __p + __sz)
2973                {
2974                    if (__p + __pos + __n1 <= __s)
2975                        __s += __n2 - __n1;
2976                    else // __p + __pos < __s < __p + __pos + __n1
2977                    {
2978                        traits_type::move(__p + __pos, __s, __n1);
2979                        __pos += __n1;
2980                        __s += __n2;
2981                        __n2 -= __n1;
2982                        __n1 = 0;
2983                    }
2984                }
2985                traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
2986            }
2987        }
2988        traits_type::move(__p + __pos, __s, __n2);
2989__finish:
2990        __sz += __n2 - __n1;
2991        __set_size(__sz);
2992        __invalidate_iterators_past(__sz);
2993        traits_type::assign(__p[__sz], value_type());
2994    }
2995    else
2996        __grow_by_and_replace(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2, __s);
2997    return *this;
2998}
2999
3000template <class _CharT, class _Traits, class _Allocator>
3001basic_string<_CharT, _Traits, _Allocator>&
3002basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, size_type __n2, value_type __c)
3003{
3004    size_type __sz = size();
3005    if (__pos > __sz)
3006        this->__throw_out_of_range();
3007    __n1 = _VSTD::min(__n1, __sz - __pos);
3008    size_type __cap = capacity();
3009    value_type* __p;
3010    if (__cap - __sz + __n1 >= __n2)
3011    {
3012        __p = _VSTD::__to_raw_pointer(__get_pointer());
3013        if (__n1 != __n2)
3014        {
3015            size_type __n_move = __sz - __pos - __n1;
3016            if (__n_move != 0)
3017                traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
3018        }
3019    }
3020    else
3021    {
3022        __grow_by(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2);
3023        __p = _VSTD::__to_raw_pointer(__get_long_pointer());
3024    }
3025    traits_type::assign(__p + __pos, __n2, __c);
3026    __sz += __n2 - __n1;
3027    __set_size(__sz);
3028    __invalidate_iterators_past(__sz);
3029    traits_type::assign(__p[__sz], value_type());
3030    return *this;
3031}
3032
3033template <class _CharT, class _Traits, class _Allocator>
3034template<class _InputIterator>
3035typename enable_if
3036<
3037    __is_input_iterator<_InputIterator>::value,
3038    basic_string<_CharT, _Traits, _Allocator>&
3039>::type
3040basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2,
3041                                                   _InputIterator __j1, _InputIterator __j2)
3042{
3043    basic_string __temp(__j1, __j2, __alloc());
3044    return this->replace(__i1, __i2, __temp);
3045}
3046
3047template <class _CharT, class _Traits, class _Allocator>
3048inline _LIBCPP_INLINE_VISIBILITY
3049basic_string<_CharT, _Traits, _Allocator>&
3050basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const basic_string& __str)
3051{
3052    return replace(__pos1, __n1, __str.data(), __str.size());
3053}
3054
3055template <class _CharT, class _Traits, class _Allocator>
3056basic_string<_CharT, _Traits, _Allocator>&
3057basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const basic_string& __str,
3058                                                   size_type __pos2, size_type __n2)
3059{
3060    size_type __str_sz = __str.size();
3061    if (__pos2 > __str_sz)
3062        this->__throw_out_of_range();
3063    return replace(__pos1, __n1, __str.data() + __pos2, _VSTD::min(__n2, __str_sz - __pos2));
3064}
3065
3066template <class _CharT, class _Traits, class _Allocator>
3067basic_string<_CharT, _Traits, _Allocator>&
3068basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s)
3069{
3070    _LIBCPP_ASSERT(__s != nullptr, "string::replace received nullptr");
3071    return replace(__pos, __n1, __s, traits_type::length(__s));
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 basic_string& __str)
3078{
3079    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1),
3080                   __str.data(), __str.size());
3081}
3082
3083template <class _CharT, class _Traits, class _Allocator>
3084inline _LIBCPP_INLINE_VISIBILITY
3085basic_string<_CharT, _Traits, _Allocator>&
3086basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const value_type* __s, size_type __n)
3087{
3088    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s, __n);
3089}
3090
3091template <class _CharT, class _Traits, class _Allocator>
3092inline _LIBCPP_INLINE_VISIBILITY
3093basic_string<_CharT, _Traits, _Allocator>&
3094basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const value_type* __s)
3095{
3096    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s);
3097}
3098
3099template <class _CharT, class _Traits, class _Allocator>
3100inline _LIBCPP_INLINE_VISIBILITY
3101basic_string<_CharT, _Traits, _Allocator>&
3102basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c)
3103{
3104    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __n, __c);
3105}
3106
3107// erase
3108
3109template <class _CharT, class _Traits, class _Allocator>
3110basic_string<_CharT, _Traits, _Allocator>&
3111basic_string<_CharT, _Traits, _Allocator>::erase(size_type __pos, size_type __n)
3112{
3113    size_type __sz = size();
3114    if (__pos > __sz)
3115        this->__throw_out_of_range();
3116    if (__n)
3117    {
3118        value_type* __p = _VSTD::__to_raw_pointer(__get_pointer());
3119        __n = _VSTD::min(__n, __sz - __pos);
3120        size_type __n_move = __sz - __pos - __n;
3121        if (__n_move != 0)
3122            traits_type::move(__p + __pos, __p + __pos + __n, __n_move);
3123        __sz -= __n;
3124        __set_size(__sz);
3125        __invalidate_iterators_past(__sz);
3126        traits_type::assign(__p[__sz], value_type());
3127    }
3128    return *this;
3129}
3130
3131template <class _CharT, class _Traits, class _Allocator>
3132inline _LIBCPP_INLINE_VISIBILITY
3133typename basic_string<_CharT, _Traits, _Allocator>::iterator
3134basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __pos)
3135{
3136#if _LIBCPP_DEBUG_LEVEL >= 2
3137    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
3138        "string::erase(iterator) called with an iterator not"
3139        " referring to this string");
3140#endif
3141    _LIBCPP_ASSERT(__pos != end(),
3142        "string::erase(iterator) called with a non-dereferenceable iterator");
3143    iterator __b = begin();
3144    size_type __r = static_cast<size_type>(__pos - __b);
3145    erase(__r, 1);
3146    return __b + static_cast<difference_type>(__r);
3147}
3148
3149template <class _CharT, class _Traits, class _Allocator>
3150inline _LIBCPP_INLINE_VISIBILITY
3151typename basic_string<_CharT, _Traits, _Allocator>::iterator
3152basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __first, const_iterator __last)
3153{
3154#if _LIBCPP_DEBUG_LEVEL >= 2
3155    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
3156        "string::erase(iterator,  iterator) called with an iterator not"
3157        " referring to this string");
3158#endif
3159    _LIBCPP_ASSERT(__first <= __last, "string::erase(first, last) called with invalid range");
3160    iterator __b = begin();
3161    size_type __r = static_cast<size_type>(__first - __b);
3162    erase(__r, static_cast<size_type>(__last - __first));
3163    return __b + static_cast<difference_type>(__r);
3164}
3165
3166template <class _CharT, class _Traits, class _Allocator>
3167inline _LIBCPP_INLINE_VISIBILITY
3168void
3169basic_string<_CharT, _Traits, _Allocator>::pop_back()
3170{
3171    _LIBCPP_ASSERT(!empty(), "string::pop_back(): string is already empty");
3172    size_type __sz;
3173    if (__is_long())
3174    {
3175        __sz = __get_long_size() - 1;
3176        __set_long_size(__sz);
3177        traits_type::assign(*(__get_long_pointer() + __sz), value_type());
3178    }
3179    else
3180    {
3181        __sz = __get_short_size() - 1;
3182        __set_short_size(__sz);
3183        traits_type::assign(*(__get_short_pointer() + __sz), value_type());
3184    }
3185    __invalidate_iterators_past(__sz);
3186}
3187
3188template <class _CharT, class _Traits, class _Allocator>
3189inline _LIBCPP_INLINE_VISIBILITY
3190void
3191basic_string<_CharT, _Traits, _Allocator>::clear() _NOEXCEPT
3192{
3193    __invalidate_all_iterators();
3194    if (__is_long())
3195    {
3196        traits_type::assign(*__get_long_pointer(), value_type());
3197        __set_long_size(0);
3198    }
3199    else
3200    {
3201        traits_type::assign(*__get_short_pointer(), value_type());
3202        __set_short_size(0);
3203    }
3204}
3205
3206template <class _CharT, class _Traits, class _Allocator>
3207inline _LIBCPP_INLINE_VISIBILITY
3208void
3209basic_string<_CharT, _Traits, _Allocator>::__erase_to_end(size_type __pos)
3210{
3211    if (__is_long())
3212    {
3213        traits_type::assign(*(__get_long_pointer() + __pos), value_type());
3214        __set_long_size(__pos);
3215    }
3216    else
3217    {
3218        traits_type::assign(*(__get_short_pointer() + __pos), value_type());
3219        __set_short_size(__pos);
3220    }
3221    __invalidate_iterators_past(__pos);
3222}
3223
3224template <class _CharT, class _Traits, class _Allocator>
3225void
3226basic_string<_CharT, _Traits, _Allocator>::resize(size_type __n, value_type __c)
3227{
3228    size_type __sz = size();
3229    if (__n > __sz)
3230        append(__n - __sz, __c);
3231    else
3232        __erase_to_end(__n);
3233}
3234
3235template <class _CharT, class _Traits, class _Allocator>
3236inline _LIBCPP_INLINE_VISIBILITY
3237typename basic_string<_CharT, _Traits, _Allocator>::size_type
3238basic_string<_CharT, _Traits, _Allocator>::max_size() const _NOEXCEPT
3239{
3240    size_type __m = __alloc_traits::max_size(__alloc());
3241#if _LIBCPP_BIG_ENDIAN
3242    return (__m <= ~__long_mask ? __m : __m/2) - __alignment;
3243#else
3244    return __m - __alignment;
3245#endif
3246}
3247
3248template <class _CharT, class _Traits, class _Allocator>
3249void
3250basic_string<_CharT, _Traits, _Allocator>::reserve(size_type __res_arg)
3251{
3252    if (__res_arg > max_size())
3253        this->__throw_length_error();
3254    size_type __cap = capacity();
3255    size_type __sz = size();
3256    __res_arg = _VSTD::max(__res_arg, __sz);
3257    __res_arg = __recommend(__res_arg);
3258    if (__res_arg != __cap)
3259    {
3260        pointer __new_data, __p;
3261        bool __was_long, __now_long;
3262        if (__res_arg == __min_cap - 1)
3263        {
3264            __was_long = true;
3265            __now_long = false;
3266            __new_data = __get_short_pointer();
3267            __p = __get_long_pointer();
3268        }
3269        else
3270        {
3271            if (__res_arg > __cap)
3272                __new_data = __alloc_traits::allocate(__alloc(), __res_arg+1);
3273            else
3274            {
3275            #ifndef _LIBCPP_NO_EXCEPTIONS
3276                try
3277                {
3278            #endif  // _LIBCPP_NO_EXCEPTIONS
3279                    __new_data = __alloc_traits::allocate(__alloc(), __res_arg+1);
3280            #ifndef _LIBCPP_NO_EXCEPTIONS
3281                }
3282                catch (...)
3283                {
3284                    return;
3285                }
3286            #else  // _LIBCPP_NO_EXCEPTIONS
3287                if (__new_data == nullptr)
3288                    return;
3289            #endif  // _LIBCPP_NO_EXCEPTIONS
3290            }
3291            __now_long = true;
3292            __was_long = __is_long();
3293            __p = __get_pointer();
3294        }
3295        traits_type::copy(_VSTD::__to_raw_pointer(__new_data),
3296                          _VSTD::__to_raw_pointer(__p), size()+1);
3297        if (__was_long)
3298            __alloc_traits::deallocate(__alloc(), __p, __cap+1);
3299        if (__now_long)
3300        {
3301            __set_long_cap(__res_arg+1);
3302            __set_long_size(__sz);
3303            __set_long_pointer(__new_data);
3304        }
3305        else
3306            __set_short_size(__sz);
3307        __invalidate_all_iterators();
3308    }
3309}
3310
3311template <class _CharT, class _Traits, class _Allocator>
3312inline _LIBCPP_INLINE_VISIBILITY
3313typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3314basic_string<_CharT, _Traits, _Allocator>::operator[](size_type __pos) const
3315{
3316    _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
3317    return *(data() + __pos);
3318}
3319
3320template <class _CharT, class _Traits, class _Allocator>
3321inline _LIBCPP_INLINE_VISIBILITY
3322typename basic_string<_CharT, _Traits, _Allocator>::reference
3323basic_string<_CharT, _Traits, _Allocator>::operator[](size_type __pos)
3324{
3325    _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
3326    return *(__get_pointer() + __pos);
3327}
3328
3329template <class _CharT, class _Traits, class _Allocator>
3330typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3331basic_string<_CharT, _Traits, _Allocator>::at(size_type __n) const
3332{
3333    if (__n >= size())
3334        this->__throw_out_of_range();
3335    return (*this)[__n];
3336}
3337
3338template <class _CharT, class _Traits, class _Allocator>
3339typename basic_string<_CharT, _Traits, _Allocator>::reference
3340basic_string<_CharT, _Traits, _Allocator>::at(size_type __n)
3341{
3342    if (__n >= size())
3343        this->__throw_out_of_range();
3344    return (*this)[__n];
3345}
3346
3347template <class _CharT, class _Traits, class _Allocator>
3348inline _LIBCPP_INLINE_VISIBILITY
3349typename basic_string<_CharT, _Traits, _Allocator>::reference
3350basic_string<_CharT, _Traits, _Allocator>::front()
3351{
3352    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
3353    return *__get_pointer();
3354}
3355
3356template <class _CharT, class _Traits, class _Allocator>
3357inline _LIBCPP_INLINE_VISIBILITY
3358typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3359basic_string<_CharT, _Traits, _Allocator>::front() const
3360{
3361    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
3362    return *data();
3363}
3364
3365template <class _CharT, class _Traits, class _Allocator>
3366inline _LIBCPP_INLINE_VISIBILITY
3367typename basic_string<_CharT, _Traits, _Allocator>::reference
3368basic_string<_CharT, _Traits, _Allocator>::back()
3369{
3370    _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
3371    return *(__get_pointer() + size() - 1);
3372}
3373
3374template <class _CharT, class _Traits, class _Allocator>
3375inline _LIBCPP_INLINE_VISIBILITY
3376typename basic_string<_CharT, _Traits, _Allocator>::const_reference
3377basic_string<_CharT, _Traits, _Allocator>::back() const
3378{
3379    _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
3380    return *(data() + size() - 1);
3381}
3382
3383template <class _CharT, class _Traits, class _Allocator>
3384typename basic_string<_CharT, _Traits, _Allocator>::size_type
3385basic_string<_CharT, _Traits, _Allocator>::copy(value_type* __s, size_type __n, size_type __pos) const
3386{
3387    size_type __sz = size();
3388    if (__pos > __sz)
3389        this->__throw_out_of_range();
3390    size_type __rlen = _VSTD::min(__n, __sz - __pos);
3391    traits_type::copy(__s, data() + __pos, __rlen);
3392    return __rlen;
3393}
3394
3395template <class _CharT, class _Traits, class _Allocator>
3396inline _LIBCPP_INLINE_VISIBILITY
3397basic_string<_CharT, _Traits, _Allocator>
3398basic_string<_CharT, _Traits, _Allocator>::substr(size_type __pos, size_type __n) const
3399{
3400    return basic_string(*this, __pos, __n, __alloc());
3401}
3402
3403template <class _CharT, class _Traits, class _Allocator>
3404inline _LIBCPP_INLINE_VISIBILITY
3405void
3406basic_string<_CharT, _Traits, _Allocator>::swap(basic_string& __str)
3407#if _LIBCPP_STD_VER >= 14
3408        _NOEXCEPT
3409#else
3410        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
3411                    __is_nothrow_swappable<allocator_type>::value)
3412#endif
3413{
3414#if _LIBCPP_DEBUG_LEVEL >= 2
3415    if (!__is_long())
3416        __get_db()->__invalidate_all(this);
3417    if (!__str.__is_long())
3418        __get_db()->__invalidate_all(&__str);
3419    __get_db()->swap(this, &__str);
3420#endif
3421    _VSTD::swap(__r_.first(), __str.__r_.first());
3422    __swap_allocator(__alloc(), __str.__alloc());
3423}
3424
3425// find
3426
3427template <class _Traits>
3428struct _LIBCPP_HIDDEN __traits_eq
3429{
3430    typedef typename _Traits::char_type char_type;
3431    _LIBCPP_INLINE_VISIBILITY
3432    bool operator()(const char_type& __x, const char_type& __y) _NOEXCEPT
3433        {return _Traits::eq(__x, __y);}
3434};
3435
3436template<class _CharT, class _Traits, class _Allocator>
3437typename basic_string<_CharT, _Traits, _Allocator>::size_type
3438basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
3439                                                size_type __pos,
3440                                                size_type __n) const _NOEXCEPT
3441{
3442    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find(): received nullptr");
3443    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3444        (data(), size(), __s, __pos, __n);
3445}
3446
3447template<class _CharT, class _Traits, class _Allocator>
3448inline _LIBCPP_INLINE_VISIBILITY
3449typename basic_string<_CharT, _Traits, _Allocator>::size_type
3450basic_string<_CharT, _Traits, _Allocator>::find(const basic_string& __str,
3451                                                size_type __pos) const _NOEXCEPT
3452{
3453    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3454        (data(), size(), __str.data(), __pos, __str.size());
3455}
3456
3457template<class _CharT, class _Traits, class _Allocator>
3458inline _LIBCPP_INLINE_VISIBILITY
3459typename basic_string<_CharT, _Traits, _Allocator>::size_type
3460basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
3461                                                size_type __pos) const _NOEXCEPT
3462{
3463    _LIBCPP_ASSERT(__s != nullptr, "string::find(): received nullptr");
3464    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3465        (data(), size(), __s, __pos, traits_type::length(__s));
3466}
3467
3468template<class _CharT, class _Traits, class _Allocator>
3469typename basic_string<_CharT, _Traits, _Allocator>::size_type
3470basic_string<_CharT, _Traits, _Allocator>::find(value_type __c,
3471                                                size_type __pos) const _NOEXCEPT
3472{
3473    return _VSTD::__str_find<value_type, size_type, traits_type, npos>
3474        (data(), size(), __c, __pos);
3475}
3476
3477// rfind
3478
3479template<class _CharT, class _Traits, class _Allocator>
3480typename basic_string<_CharT, _Traits, _Allocator>::size_type
3481basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
3482                                                 size_type __pos,
3483                                                 size_type __n) const _NOEXCEPT
3484{
3485    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::rfind(): received nullptr");
3486    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3487        (data(), size(), __s, __pos, __n);
3488}
3489
3490template<class _CharT, class _Traits, class _Allocator>
3491inline _LIBCPP_INLINE_VISIBILITY
3492typename basic_string<_CharT, _Traits, _Allocator>::size_type
3493basic_string<_CharT, _Traits, _Allocator>::rfind(const basic_string& __str,
3494                                                 size_type __pos) const _NOEXCEPT
3495{
3496    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3497        (data(), size(), __str.data(), __pos, __str.size());
3498}
3499
3500template<class _CharT, class _Traits, class _Allocator>
3501inline _LIBCPP_INLINE_VISIBILITY
3502typename basic_string<_CharT, _Traits, _Allocator>::size_type
3503basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
3504                                                 size_type __pos) const _NOEXCEPT
3505{
3506    _LIBCPP_ASSERT(__s != nullptr, "string::rfind(): received nullptr");
3507    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3508        (data(), size(), __s, __pos, traits_type::length(__s));
3509}
3510
3511template<class _CharT, class _Traits, class _Allocator>
3512typename basic_string<_CharT, _Traits, _Allocator>::size_type
3513basic_string<_CharT, _Traits, _Allocator>::rfind(value_type __c,
3514                                                 size_type __pos) const _NOEXCEPT
3515{
3516    return _VSTD::__str_rfind<value_type, size_type, traits_type, npos>
3517        (data(), size(), __c, __pos);
3518}
3519
3520// find_first_of
3521
3522template<class _CharT, class _Traits, class _Allocator>
3523typename basic_string<_CharT, _Traits, _Allocator>::size_type
3524basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
3525                                                         size_type __pos,
3526                                                         size_type __n) const _NOEXCEPT
3527{
3528    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_first_of(): received nullptr");
3529    return _VSTD::__str_find_first_of<value_type, size_type, traits_type, npos>
3530        (data(), size(), __s, __pos, __n);
3531}
3532
3533template<class _CharT, class _Traits, class _Allocator>
3534inline _LIBCPP_INLINE_VISIBILITY
3535typename basic_string<_CharT, _Traits, _Allocator>::size_type
3536basic_string<_CharT, _Traits, _Allocator>::find_first_of(const basic_string& __str,
3537                                                         size_type __pos) const _NOEXCEPT
3538{
3539    return _VSTD::__str_find_first_of<value_type, size_type, traits_type, npos>
3540        (data(), size(), __str.data(), __pos, __str.size());
3541}
3542
3543template<class _CharT, class _Traits, class _Allocator>
3544inline _LIBCPP_INLINE_VISIBILITY
3545typename basic_string<_CharT, _Traits, _Allocator>::size_type
3546basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
3547                                                         size_type __pos) const _NOEXCEPT
3548{
3549    _LIBCPP_ASSERT(__s != nullptr, "string::find_first_of(): received nullptr");
3550    return _VSTD::__str_find_first_of<value_type, size_type, traits_type, npos>
3551        (data(), size(), __s, __pos, traits_type::length(__s));
3552}
3553
3554template<class _CharT, class _Traits, class _Allocator>
3555inline _LIBCPP_INLINE_VISIBILITY
3556typename basic_string<_CharT, _Traits, _Allocator>::size_type
3557basic_string<_CharT, _Traits, _Allocator>::find_first_of(value_type __c,
3558                                                         size_type __pos) const _NOEXCEPT
3559{
3560    return find(__c, __pos);
3561}
3562
3563// find_last_of
3564
3565template<class _CharT, class _Traits, class _Allocator>
3566typename basic_string<_CharT, _Traits, _Allocator>::size_type
3567basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
3568                                                        size_type __pos,
3569                                                        size_type __n) const _NOEXCEPT
3570{
3571    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_last_of(): received nullptr");
3572    return _VSTD::__str_find_last_of<value_type, size_type, traits_type, npos>
3573        (data(), size(), __s, __pos, __n);
3574}
3575
3576template<class _CharT, class _Traits, class _Allocator>
3577inline _LIBCPP_INLINE_VISIBILITY
3578typename basic_string<_CharT, _Traits, _Allocator>::size_type
3579basic_string<_CharT, _Traits, _Allocator>::find_last_of(const basic_string& __str,
3580                                                        size_type __pos) const _NOEXCEPT
3581{
3582    return _VSTD::__str_find_last_of<value_type, size_type, traits_type, npos>
3583        (data(), size(), __str.data(), __pos, __str.size());
3584}
3585
3586template<class _CharT, class _Traits, class _Allocator>
3587inline _LIBCPP_INLINE_VISIBILITY
3588typename basic_string<_CharT, _Traits, _Allocator>::size_type
3589basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
3590                                                        size_type __pos) const _NOEXCEPT
3591{
3592    _LIBCPP_ASSERT(__s != nullptr, "string::find_last_of(): received nullptr");
3593    return _VSTD::__str_find_last_of<value_type, size_type, traits_type, npos>
3594        (data(), size(), __s, __pos, traits_type::length(__s));
3595}
3596
3597template<class _CharT, class _Traits, class _Allocator>
3598inline _LIBCPP_INLINE_VISIBILITY
3599typename basic_string<_CharT, _Traits, _Allocator>::size_type
3600basic_string<_CharT, _Traits, _Allocator>::find_last_of(value_type __c,
3601                                                        size_type __pos) const _NOEXCEPT
3602{
3603    return rfind(__c, __pos);
3604}
3605
3606// find_first_not_of
3607
3608template<class _CharT, class _Traits, class _Allocator>
3609typename basic_string<_CharT, _Traits, _Allocator>::size_type
3610basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
3611                                                             size_type __pos,
3612                                                             size_type __n) const _NOEXCEPT
3613{
3614    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_first_not_of(): received nullptr");
3615    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3616        (data(), size(), __s, __pos, __n);
3617}
3618
3619template<class _CharT, class _Traits, class _Allocator>
3620inline _LIBCPP_INLINE_VISIBILITY
3621typename basic_string<_CharT, _Traits, _Allocator>::size_type
3622basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const basic_string& __str,
3623                                                             size_type __pos) const _NOEXCEPT
3624{
3625    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3626        (data(), size(), __str.data(), __pos, __str.size());
3627}
3628
3629template<class _CharT, class _Traits, class _Allocator>
3630inline _LIBCPP_INLINE_VISIBILITY
3631typename basic_string<_CharT, _Traits, _Allocator>::size_type
3632basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
3633                                                             size_type __pos) const _NOEXCEPT
3634{
3635    _LIBCPP_ASSERT(__s != nullptr, "string::find_first_not_of(): received nullptr");
3636    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3637        (data(), size(), __s, __pos, traits_type::length(__s));
3638}
3639
3640template<class _CharT, class _Traits, class _Allocator>
3641inline _LIBCPP_INLINE_VISIBILITY
3642typename basic_string<_CharT, _Traits, _Allocator>::size_type
3643basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(value_type __c,
3644                                                             size_type __pos) const _NOEXCEPT
3645{
3646    return _VSTD::__str_find_first_not_of<value_type, size_type, traits_type, npos>
3647        (data(), size(), __c, __pos);
3648}
3649
3650// find_last_not_of
3651
3652template<class _CharT, class _Traits, class _Allocator>
3653typename basic_string<_CharT, _Traits, _Allocator>::size_type
3654basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
3655                                                            size_type __pos,
3656                                                            size_type __n) const _NOEXCEPT
3657{
3658    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_last_not_of(): received nullptr");
3659    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3660        (data(), size(), __s, __pos, __n);
3661}
3662
3663template<class _CharT, class _Traits, class _Allocator>
3664inline _LIBCPP_INLINE_VISIBILITY
3665typename basic_string<_CharT, _Traits, _Allocator>::size_type
3666basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const basic_string& __str,
3667                                                            size_type __pos) const _NOEXCEPT
3668{
3669    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3670        (data(), size(), __str.data(), __pos, __str.size());
3671}
3672
3673template<class _CharT, class _Traits, class _Allocator>
3674inline _LIBCPP_INLINE_VISIBILITY
3675typename basic_string<_CharT, _Traits, _Allocator>::size_type
3676basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
3677                                                            size_type __pos) const _NOEXCEPT
3678{
3679    _LIBCPP_ASSERT(__s != nullptr, "string::find_last_not_of(): received nullptr");
3680    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3681        (data(), size(), __s, __pos, traits_type::length(__s));
3682}
3683
3684template<class _CharT, class _Traits, class _Allocator>
3685inline _LIBCPP_INLINE_VISIBILITY
3686typename basic_string<_CharT, _Traits, _Allocator>::size_type
3687basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(value_type __c,
3688                                                            size_type __pos) const _NOEXCEPT
3689{
3690    return _VSTD::__str_find_last_not_of<value_type, size_type, traits_type, npos>
3691        (data(), size(), __c, __pos);
3692}
3693
3694// compare
3695
3696template <class _CharT, class _Traits, class _Allocator>
3697inline _LIBCPP_INLINE_VISIBILITY
3698int
3699basic_string<_CharT, _Traits, _Allocator>::compare(const basic_string& __str) const _NOEXCEPT
3700{
3701    size_t __lhs_sz = size();
3702    size_t __rhs_sz = __str.size();
3703    int __result = traits_type::compare(data(), __str.data(),
3704                                        _VSTD::min(__lhs_sz, __rhs_sz));
3705    if (__result != 0)
3706        return __result;
3707    if (__lhs_sz < __rhs_sz)
3708        return -1;
3709    if (__lhs_sz > __rhs_sz)
3710        return 1;
3711    return 0;
3712}
3713
3714template <class _CharT, class _Traits, class _Allocator>
3715inline _LIBCPP_INLINE_VISIBILITY
3716int
3717basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3718                                                   size_type __n1,
3719                                                   const basic_string& __str) const
3720{
3721    return compare(__pos1, __n1, __str.data(), __str.size());
3722}
3723
3724template <class _CharT, class _Traits, class _Allocator>
3725int
3726basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3727                                                   size_type __n1,
3728                                                   const basic_string& __str,
3729                                                   size_type __pos2,
3730                                                   size_type __n2) const
3731{
3732    size_type __sz = __str.size();
3733    if (__pos2 > __sz)
3734        this->__throw_out_of_range();
3735    return compare(__pos1, __n1, __str.data() + __pos2, _VSTD::min(__n2,
3736                                                                  __sz - __pos2));
3737}
3738
3739template <class _CharT, class _Traits, class _Allocator>
3740int
3741basic_string<_CharT, _Traits, _Allocator>::compare(const value_type* __s) const _NOEXCEPT
3742{
3743    _LIBCPP_ASSERT(__s != nullptr, "string::compare(): received nullptr");
3744    return compare(0, npos, __s, traits_type::length(__s));
3745}
3746
3747template <class _CharT, class _Traits, class _Allocator>
3748int
3749basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3750                                                   size_type __n1,
3751                                                   const value_type* __s) const
3752{
3753    _LIBCPP_ASSERT(__s != nullptr, "string::compare(): received nullptr");
3754    return compare(__pos1, __n1, __s, traits_type::length(__s));
3755}
3756
3757template <class _CharT, class _Traits, class _Allocator>
3758int
3759basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
3760                                                   size_type __n1,
3761                                                   const value_type* __s,
3762                                                   size_type __n2) const
3763{
3764    _LIBCPP_ASSERT(__n2 == 0 || __s != nullptr, "string::compare(): received nullptr");
3765    size_type __sz = size();
3766    if (__pos1 > __sz || __n2 == npos)
3767        this->__throw_out_of_range();
3768    size_type __rlen = _VSTD::min(__n1, __sz - __pos1);
3769    int __r = traits_type::compare(data() + __pos1, __s, _VSTD::min(__rlen, __n2));
3770    if (__r == 0)
3771    {
3772        if (__rlen < __n2)
3773            __r = -1;
3774        else if (__rlen > __n2)
3775            __r = 1;
3776    }
3777    return __r;
3778}
3779
3780// __invariants
3781
3782template<class _CharT, class _Traits, class _Allocator>
3783inline _LIBCPP_INLINE_VISIBILITY
3784bool
3785basic_string<_CharT, _Traits, _Allocator>::__invariants() const
3786{
3787    if (size() > capacity())
3788        return false;
3789    if (capacity() < __min_cap - 1)
3790        return false;
3791    if (data() == 0)
3792        return false;
3793    if (data()[size()] != value_type(0))
3794        return false;
3795    return true;
3796}
3797
3798// operator==
3799
3800template<class _CharT, class _Traits, class _Allocator>
3801inline _LIBCPP_INLINE_VISIBILITY
3802bool
3803operator==(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3804           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3805{
3806    size_t __lhs_sz = __lhs.size();
3807    return __lhs_sz == __rhs.size() && _Traits::compare(__lhs.data(),
3808                                                        __rhs.data(),
3809                                                        __lhs_sz) == 0;
3810}
3811
3812template<class _Allocator>
3813inline _LIBCPP_INLINE_VISIBILITY
3814bool
3815operator==(const basic_string<char, char_traits<char>, _Allocator>& __lhs,
3816           const basic_string<char, char_traits<char>, _Allocator>& __rhs) _NOEXCEPT
3817{
3818    size_t __lhs_sz = __lhs.size();
3819    if (__lhs_sz != __rhs.size())
3820        return false;
3821    const char* __lp = __lhs.data();
3822    const char* __rp = __rhs.data();
3823    if (__lhs.__is_long())
3824        return char_traits<char>::compare(__lp, __rp, __lhs_sz) == 0;
3825    for (; __lhs_sz != 0; --__lhs_sz, ++__lp, ++__rp)
3826        if (*__lp != *__rp)
3827            return false;
3828    return true;
3829}
3830
3831template<class _CharT, class _Traits, class _Allocator>
3832inline _LIBCPP_INLINE_VISIBILITY
3833bool
3834operator==(const _CharT* __lhs,
3835           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3836{
3837    typedef basic_string<_CharT, _Traits, _Allocator> _String;
3838    _LIBCPP_ASSERT(__lhs != nullptr, "operator==(char*, basic_string): received nullptr");
3839    size_t __lhs_len = _Traits::length(__lhs);
3840    if (__lhs_len != __rhs.size()) return false;
3841    return __rhs.compare(0, _String::npos, __lhs, __lhs_len) == 0;
3842}
3843
3844template<class _CharT, class _Traits, class _Allocator>
3845inline _LIBCPP_INLINE_VISIBILITY
3846bool
3847operator==(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
3848           const _CharT* __rhs) _NOEXCEPT
3849{
3850    typedef basic_string<_CharT, _Traits, _Allocator> _String;
3851    _LIBCPP_ASSERT(__rhs != nullptr, "operator==(basic_string, char*): received nullptr");
3852    size_t __rhs_len = _Traits::length(__rhs);
3853    if (__rhs_len != __lhs.size()) return false;
3854    return __lhs.compare(0, _String::npos, __rhs, __rhs_len) == 0;
3855}
3856
3857// operator!=
3858
3859template<class _CharT, class _Traits, class _Allocator>
3860inline _LIBCPP_INLINE_VISIBILITY
3861bool
3862operator!=(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
3863           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3864{
3865    return !(__lhs == __rhs);
3866}
3867
3868template<class _CharT, class _Traits, class _Allocator>
3869inline _LIBCPP_INLINE_VISIBILITY
3870bool
3871operator!=(const _CharT* __lhs,
3872           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3873{
3874    return !(__lhs == __rhs);
3875}
3876
3877template<class _CharT, class _Traits, class _Allocator>
3878inline _LIBCPP_INLINE_VISIBILITY
3879bool
3880operator!=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3881           const _CharT* __rhs) _NOEXCEPT
3882{
3883    return !(__lhs == __rhs);
3884}
3885
3886// operator<
3887
3888template<class _CharT, class _Traits, class _Allocator>
3889inline _LIBCPP_INLINE_VISIBILITY
3890bool
3891operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3892           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3893{
3894    return __lhs.compare(__rhs) < 0;
3895}
3896
3897template<class _CharT, class _Traits, class _Allocator>
3898inline _LIBCPP_INLINE_VISIBILITY
3899bool
3900operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3901           const _CharT* __rhs) _NOEXCEPT
3902{
3903    return __lhs.compare(__rhs) < 0;
3904}
3905
3906template<class _CharT, class _Traits, class _Allocator>
3907inline _LIBCPP_INLINE_VISIBILITY
3908bool
3909operator< (const _CharT* __lhs,
3910           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3911{
3912    return __rhs.compare(__lhs) > 0;
3913}
3914
3915// operator>
3916
3917template<class _CharT, class _Traits, class _Allocator>
3918inline _LIBCPP_INLINE_VISIBILITY
3919bool
3920operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3921           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3922{
3923    return __rhs < __lhs;
3924}
3925
3926template<class _CharT, class _Traits, class _Allocator>
3927inline _LIBCPP_INLINE_VISIBILITY
3928bool
3929operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3930           const _CharT* __rhs) _NOEXCEPT
3931{
3932    return __rhs < __lhs;
3933}
3934
3935template<class _CharT, class _Traits, class _Allocator>
3936inline _LIBCPP_INLINE_VISIBILITY
3937bool
3938operator> (const _CharT* __lhs,
3939           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3940{
3941    return __rhs < __lhs;
3942}
3943
3944// operator<=
3945
3946template<class _CharT, class _Traits, class _Allocator>
3947inline _LIBCPP_INLINE_VISIBILITY
3948bool
3949operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3950           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3951{
3952    return !(__rhs < __lhs);
3953}
3954
3955template<class _CharT, class _Traits, class _Allocator>
3956inline _LIBCPP_INLINE_VISIBILITY
3957bool
3958operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3959           const _CharT* __rhs) _NOEXCEPT
3960{
3961    return !(__rhs < __lhs);
3962}
3963
3964template<class _CharT, class _Traits, class _Allocator>
3965inline _LIBCPP_INLINE_VISIBILITY
3966bool
3967operator<=(const _CharT* __lhs,
3968           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3969{
3970    return !(__rhs < __lhs);
3971}
3972
3973// operator>=
3974
3975template<class _CharT, class _Traits, class _Allocator>
3976inline _LIBCPP_INLINE_VISIBILITY
3977bool
3978operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3979           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3980{
3981    return !(__lhs < __rhs);
3982}
3983
3984template<class _CharT, class _Traits, class _Allocator>
3985inline _LIBCPP_INLINE_VISIBILITY
3986bool
3987operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
3988           const _CharT* __rhs) _NOEXCEPT
3989{
3990    return !(__lhs < __rhs);
3991}
3992
3993template<class _CharT, class _Traits, class _Allocator>
3994inline _LIBCPP_INLINE_VISIBILITY
3995bool
3996operator>=(const _CharT* __lhs,
3997           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
3998{
3999    return !(__lhs < __rhs);
4000}
4001
4002// operator +
4003
4004template<class _CharT, class _Traits, class _Allocator>
4005basic_string<_CharT, _Traits, _Allocator>
4006operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
4007          const basic_string<_CharT, _Traits, _Allocator>& __rhs)
4008{
4009    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
4010    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
4011    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
4012    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + __rhs_sz);
4013    __r.append(__rhs.data(), __rhs_sz);
4014    return __r;
4015}
4016
4017template<class _CharT, class _Traits, class _Allocator>
4018basic_string<_CharT, _Traits, _Allocator>
4019operator+(const _CharT* __lhs , const basic_string<_CharT,_Traits,_Allocator>& __rhs)
4020{
4021    basic_string<_CharT, _Traits, _Allocator> __r(__rhs.get_allocator());
4022    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = _Traits::length(__lhs);
4023    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
4024    __r.__init(__lhs, __lhs_sz, __lhs_sz + __rhs_sz);
4025    __r.append(__rhs.data(), __rhs_sz);
4026    return __r;
4027}
4028
4029template<class _CharT, class _Traits, class _Allocator>
4030basic_string<_CharT, _Traits, _Allocator>
4031operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Allocator>& __rhs)
4032{
4033    basic_string<_CharT, _Traits, _Allocator> __r(__rhs.get_allocator());
4034    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
4035    __r.__init(&__lhs, 1, 1 + __rhs_sz);
4036    __r.append(__rhs.data(), __rhs_sz);
4037    return __r;
4038}
4039
4040template<class _CharT, class _Traits, class _Allocator>
4041basic_string<_CharT, _Traits, _Allocator>
4042operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs)
4043{
4044    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
4045    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
4046    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = _Traits::length(__rhs);
4047    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + __rhs_sz);
4048    __r.append(__rhs, __rhs_sz);
4049    return __r;
4050}
4051
4052template<class _CharT, class _Traits, class _Allocator>
4053basic_string<_CharT, _Traits, _Allocator>
4054operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, _CharT __rhs)
4055{
4056    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
4057    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
4058    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + 1);
4059    __r.push_back(__rhs);
4060    return __r;
4061}
4062
4063#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
4064
4065template<class _CharT, class _Traits, class _Allocator>
4066inline _LIBCPP_INLINE_VISIBILITY
4067basic_string<_CharT, _Traits, _Allocator>
4068operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const basic_string<_CharT, _Traits, _Allocator>& __rhs)
4069{
4070    return _VSTD::move(__lhs.append(__rhs));
4071}
4072
4073template<class _CharT, class _Traits, class _Allocator>
4074inline _LIBCPP_INLINE_VISIBILITY
4075basic_string<_CharT, _Traits, _Allocator>
4076operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
4077{
4078    return _VSTD::move(__rhs.insert(0, __lhs));
4079}
4080
4081template<class _CharT, class _Traits, class _Allocator>
4082inline _LIBCPP_INLINE_VISIBILITY
4083basic_string<_CharT, _Traits, _Allocator>
4084operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
4085{
4086    return _VSTD::move(__lhs.append(__rhs));
4087}
4088
4089template<class _CharT, class _Traits, class _Allocator>
4090inline _LIBCPP_INLINE_VISIBILITY
4091basic_string<_CharT, _Traits, _Allocator>
4092operator+(const _CharT* __lhs , basic_string<_CharT,_Traits,_Allocator>&& __rhs)
4093{
4094    return _VSTD::move(__rhs.insert(0, __lhs));
4095}
4096
4097template<class _CharT, class _Traits, class _Allocator>
4098inline _LIBCPP_INLINE_VISIBILITY
4099basic_string<_CharT, _Traits, _Allocator>
4100operator+(_CharT __lhs, basic_string<_CharT,_Traits,_Allocator>&& __rhs)
4101{
4102    __rhs.insert(__rhs.begin(), __lhs);
4103    return _VSTD::move(__rhs);
4104}
4105
4106template<class _CharT, class _Traits, class _Allocator>
4107inline _LIBCPP_INLINE_VISIBILITY
4108basic_string<_CharT, _Traits, _Allocator>
4109operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const _CharT* __rhs)
4110{
4111    return _VSTD::move(__lhs.append(__rhs));
4112}
4113
4114template<class _CharT, class _Traits, class _Allocator>
4115inline _LIBCPP_INLINE_VISIBILITY
4116basic_string<_CharT, _Traits, _Allocator>
4117operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, _CharT __rhs)
4118{
4119    __lhs.push_back(__rhs);
4120    return _VSTD::move(__lhs);
4121}
4122
4123#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
4124
4125// swap
4126
4127template<class _CharT, class _Traits, class _Allocator>
4128inline _LIBCPP_INLINE_VISIBILITY
4129void
4130swap(basic_string<_CharT, _Traits, _Allocator>& __lhs,
4131     basic_string<_CharT, _Traits, _Allocator>& __rhs)
4132     _NOEXCEPT_(_NOEXCEPT_(__lhs.swap(__rhs)))
4133{
4134    __lhs.swap(__rhs);
4135}
4136
4137#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
4138
4139typedef basic_string<char16_t> u16string;
4140typedef basic_string<char32_t> u32string;
4141
4142#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
4143
4144_LIBCPP_FUNC_VIS int                stoi  (const string& __str, size_t* __idx = 0, int __base = 10);
4145_LIBCPP_FUNC_VIS long               stol  (const string& __str, size_t* __idx = 0, int __base = 10);
4146_LIBCPP_FUNC_VIS unsigned long      stoul (const string& __str, size_t* __idx = 0, int __base = 10);
4147_LIBCPP_FUNC_VIS long long          stoll (const string& __str, size_t* __idx = 0, int __base = 10);
4148_LIBCPP_FUNC_VIS unsigned long long stoull(const string& __str, size_t* __idx = 0, int __base = 10);
4149
4150_LIBCPP_FUNC_VIS float       stof (const string& __str, size_t* __idx = 0);
4151_LIBCPP_FUNC_VIS double      stod (const string& __str, size_t* __idx = 0);
4152_LIBCPP_FUNC_VIS long double stold(const string& __str, size_t* __idx = 0);
4153
4154_LIBCPP_FUNC_VIS string to_string(int __val);
4155_LIBCPP_FUNC_VIS string to_string(unsigned __val);
4156_LIBCPP_FUNC_VIS string to_string(long __val);
4157_LIBCPP_FUNC_VIS string to_string(unsigned long __val);
4158_LIBCPP_FUNC_VIS string to_string(long long __val);
4159_LIBCPP_FUNC_VIS string to_string(unsigned long long __val);
4160_LIBCPP_FUNC_VIS string to_string(float __val);
4161_LIBCPP_FUNC_VIS string to_string(double __val);
4162_LIBCPP_FUNC_VIS string to_string(long double __val);
4163
4164_LIBCPP_FUNC_VIS int                stoi  (const wstring& __str, size_t* __idx = 0, int __base = 10);
4165_LIBCPP_FUNC_VIS long               stol  (const wstring& __str, size_t* __idx = 0, int __base = 10);
4166_LIBCPP_FUNC_VIS unsigned long      stoul (const wstring& __str, size_t* __idx = 0, int __base = 10);
4167_LIBCPP_FUNC_VIS long long          stoll (const wstring& __str, size_t* __idx = 0, int __base = 10);
4168_LIBCPP_FUNC_VIS unsigned long long stoull(const wstring& __str, size_t* __idx = 0, int __base = 10);
4169
4170_LIBCPP_FUNC_VIS float       stof (const wstring& __str, size_t* __idx = 0);
4171_LIBCPP_FUNC_VIS double      stod (const wstring& __str, size_t* __idx = 0);
4172_LIBCPP_FUNC_VIS long double stold(const wstring& __str, size_t* __idx = 0);
4173
4174_LIBCPP_FUNC_VIS wstring to_wstring(int __val);
4175_LIBCPP_FUNC_VIS wstring to_wstring(unsigned __val);
4176_LIBCPP_FUNC_VIS wstring to_wstring(long __val);
4177_LIBCPP_FUNC_VIS wstring to_wstring(unsigned long __val);
4178_LIBCPP_FUNC_VIS wstring to_wstring(long long __val);
4179_LIBCPP_FUNC_VIS wstring to_wstring(unsigned long long __val);
4180_LIBCPP_FUNC_VIS wstring to_wstring(float __val);
4181_LIBCPP_FUNC_VIS wstring to_wstring(double __val);
4182_LIBCPP_FUNC_VIS wstring to_wstring(long double __val);
4183
4184template<class _CharT, class _Traits, class _Allocator>
4185    const typename basic_string<_CharT, _Traits, _Allocator>::size_type
4186                   basic_string<_CharT, _Traits, _Allocator>::npos;
4187
4188template<class _CharT, class _Traits, class _Allocator>
4189struct _LIBCPP_TYPE_VIS_ONLY hash<basic_string<_CharT, _Traits, _Allocator> >
4190    : public unary_function<basic_string<_CharT, _Traits, _Allocator>, size_t>
4191{
4192    size_t
4193        operator()(const basic_string<_CharT, _Traits, _Allocator>& __val) const _NOEXCEPT;
4194};
4195
4196template<class _CharT, class _Traits, class _Allocator>
4197size_t
4198hash<basic_string<_CharT, _Traits, _Allocator> >::operator()(
4199        const basic_string<_CharT, _Traits, _Allocator>& __val) const _NOEXCEPT
4200{
4201    return __do_string_hash(__val.data(), __val.data() + __val.size());
4202}
4203
4204template<class _CharT, class _Traits, class _Allocator>
4205basic_ostream<_CharT, _Traits>&
4206operator<<(basic_ostream<_CharT, _Traits>& __os,
4207           const basic_string<_CharT, _Traits, _Allocator>& __str);
4208
4209template<class _CharT, class _Traits, class _Allocator>
4210basic_istream<_CharT, _Traits>&
4211operator>>(basic_istream<_CharT, _Traits>& __is,
4212           basic_string<_CharT, _Traits, _Allocator>& __str);
4213
4214template<class _CharT, class _Traits, class _Allocator>
4215basic_istream<_CharT, _Traits>&
4216getline(basic_istream<_CharT, _Traits>& __is,
4217        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
4218
4219template<class _CharT, class _Traits, class _Allocator>
4220inline _LIBCPP_INLINE_VISIBILITY
4221basic_istream<_CharT, _Traits>&
4222getline(basic_istream<_CharT, _Traits>& __is,
4223        basic_string<_CharT, _Traits, _Allocator>& __str);
4224
4225#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
4226
4227template<class _CharT, class _Traits, class _Allocator>
4228inline _LIBCPP_INLINE_VISIBILITY
4229basic_istream<_CharT, _Traits>&
4230getline(basic_istream<_CharT, _Traits>&& __is,
4231        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
4232
4233template<class _CharT, class _Traits, class _Allocator>
4234inline _LIBCPP_INLINE_VISIBILITY
4235basic_istream<_CharT, _Traits>&
4236getline(basic_istream<_CharT, _Traits>&& __is,
4237        basic_string<_CharT, _Traits, _Allocator>& __str);
4238
4239#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
4240
4241#if _LIBCPP_DEBUG_LEVEL >= 2
4242
4243template<class _CharT, class _Traits, class _Allocator>
4244bool
4245basic_string<_CharT, _Traits, _Allocator>::__dereferenceable(const const_iterator* __i) const
4246{
4247    return this->data() <= _VSTD::__to_raw_pointer(__i->base()) &&
4248           _VSTD::__to_raw_pointer(__i->base()) < this->data() + this->size();
4249}
4250
4251template<class _CharT, class _Traits, class _Allocator>
4252bool
4253basic_string<_CharT, _Traits, _Allocator>::__decrementable(const const_iterator* __i) const
4254{
4255    return this->data() < _VSTD::__to_raw_pointer(__i->base()) &&
4256           _VSTD::__to_raw_pointer(__i->base()) <= this->data() + this->size();
4257}
4258
4259template<class _CharT, class _Traits, class _Allocator>
4260bool
4261basic_string<_CharT, _Traits, _Allocator>::__addable(const const_iterator* __i, ptrdiff_t __n) const
4262{
4263    const value_type* __p = _VSTD::__to_raw_pointer(__i->base()) + __n;
4264    return this->data() <= __p && __p <= this->data() + this->size();
4265}
4266
4267template<class _CharT, class _Traits, class _Allocator>
4268bool
4269basic_string<_CharT, _Traits, _Allocator>::__subscriptable(const const_iterator* __i, ptrdiff_t __n) const
4270{
4271    const value_type* __p = _VSTD::__to_raw_pointer(__i->base()) + __n;
4272    return this->data() <= __p && __p < this->data() + this->size();
4273}
4274
4275#endif  // _LIBCPP_DEBUG_LEVEL >= 2
4276
4277#if _LIBCPP_STD_VER > 11
4278// Literal suffixes for basic_string [basic.string.literals]
4279inline namespace literals
4280{
4281  inline namespace string_literals
4282  {
4283    inline _LIBCPP_INLINE_VISIBILITY
4284    basic_string<char> operator "" s( const char *__str, size_t __len )
4285    {
4286        return basic_string<char> (__str, __len);
4287    }
4288
4289    inline _LIBCPP_INLINE_VISIBILITY
4290    basic_string<wchar_t> operator "" s( const wchar_t *__str, size_t __len )
4291    {
4292        return basic_string<wchar_t> (__str, __len);
4293    }
4294
4295    inline _LIBCPP_INLINE_VISIBILITY
4296    basic_string<char16_t> operator "" s( const char16_t *__str, size_t __len )
4297    {
4298        return basic_string<char16_t> (__str, __len);
4299    }
4300
4301    inline _LIBCPP_INLINE_VISIBILITY
4302    basic_string<char32_t> operator "" s( const char32_t *__str, size_t __len )
4303    {
4304        return basic_string<char32_t> (__str, __len);
4305    }
4306  }
4307}
4308#endif
4309
4310_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS basic_string<char>)
4311_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS basic_string<wchar_t>)
4312_LIBCPP_EXTERN_TEMPLATE(string operator+<char, char_traits<char>, allocator<char> >(char const*, string const&))
4313
4314_LIBCPP_END_NAMESPACE_STD
4315
4316#endif  // _LIBCPP_STRING
4317