LCOV - code coverage report
Current view: top level - v1 - string (source / functions) Coverage Total Hit
Test: vrml_testfiles.info Lines: 72.2 % 151 109
Test Date: 2024-03-08 16:12:17 Functions: 78.3 % 46 36

            Line data    Source code
       1              : // -*- C++ -*-
       2              : //===----------------------------------------------------------------------===//
       3              : //
       4              : // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
       5              : // See https://llvm.org/LICENSE.txt for license information.
       6              : // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
       7              : //
       8              : //===----------------------------------------------------------------------===//
       9              : 
      10              : #ifndef _LIBCPP_STRING
      11              : #define _LIBCPP_STRING
      12              : 
      13              : /*
      14              :     string synopsis
      15              : 
      16              : #include <compare>
      17              : #include <initializer_list>
      18              : 
      19              : namespace std
      20              : {
      21              : 
      22              : template <class stateT>
      23              : class fpos
      24              : {
      25              : private:
      26              :     stateT st;
      27              : public:
      28              :     fpos(streamoff = streamoff());
      29              : 
      30              :     operator streamoff() const;
      31              : 
      32              :     stateT state() const;
      33              :     void state(stateT);
      34              : 
      35              :     fpos& operator+=(streamoff);
      36              :     fpos  operator+ (streamoff) const;
      37              :     fpos& operator-=(streamoff);
      38              :     fpos  operator- (streamoff) const;
      39              : };
      40              : 
      41              : template <class stateT> streamoff operator-(const fpos<stateT>& x, const fpos<stateT>& y);
      42              : 
      43              : template <class stateT> bool operator==(const fpos<stateT>& x, const fpos<stateT>& y);
      44              : template <class stateT> bool operator!=(const fpos<stateT>& x, const fpos<stateT>& y);
      45              : 
      46              : template <class charT>
      47              : struct char_traits
      48              : {
      49              :     using char_type           = charT;
      50              :     using int_type            = ...;
      51              :     using off_type            = streamoff;
      52              :     using pos_type            = streampos;
      53              :     using state_type          = mbstate_t;
      54              :     using comparison_category = strong_ordering; // Since C++20 only for the specializations
      55              :                                                  // char, wchar_t, char8_t, char16_t, and char32_t.
      56              : 
      57              :     static void assign(char_type& c1, const char_type& c2) noexcept;
      58              :     static constexpr bool eq(char_type c1, char_type c2) noexcept;
      59              :     static constexpr bool lt(char_type c1, char_type c2) noexcept;
      60              : 
      61              :     static int              compare(const char_type* s1, const char_type* s2, size_t n);
      62              :     static size_t           length(const char_type* s);
      63              :     static const char_type* find(const char_type* s, size_t n, const char_type& a);
      64              :     static char_type*       move(char_type* s1, const char_type* s2, size_t n);
      65              :     static char_type*       copy(char_type* s1, const char_type* s2, size_t n);
      66              :     static char_type*       assign(char_type* s, size_t n, char_type a);
      67              : 
      68              :     static constexpr int_type  not_eof(int_type c) noexcept;
      69              :     static constexpr char_type to_char_type(int_type c) noexcept;
      70              :     static constexpr int_type  to_int_type(char_type c) noexcept;
      71              :     static constexpr bool      eq_int_type(int_type c1, int_type c2) noexcept;
      72              :     static constexpr int_type  eof() noexcept;
      73              : };
      74              : 
      75              : template <> struct char_traits<char>;
      76              : template <> struct char_traits<wchar_t>;
      77              : template <> struct char_traits<char8_t>;  // C++20
      78              : template <> struct char_traits<char16_t>;
      79              : template <> struct char_traits<char32_t>;
      80              : 
      81              : template<class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
      82              : class basic_string
      83              : {
      84              : public:
      85              : // types:
      86              :     typedef traits traits_type;
      87              :     typedef typename traits_type::char_type value_type;
      88              :     typedef Allocator allocator_type;
      89              :     typedef typename allocator_type::size_type size_type;
      90              :     typedef typename allocator_type::difference_type difference_type;
      91              :     typedef typename allocator_type::reference reference;
      92              :     typedef typename allocator_type::const_reference const_reference;
      93              :     typedef typename allocator_type::pointer pointer;
      94              :     typedef typename allocator_type::const_pointer const_pointer;
      95              :     typedef implementation-defined iterator;
      96              :     typedef implementation-defined const_iterator;
      97              :     typedef std::reverse_iterator<iterator> reverse_iterator;
      98              :     typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
      99              : 
     100              :     static const size_type npos = -1;
     101              : 
     102              :     basic_string()
     103              :         noexcept(is_nothrow_default_constructible<allocator_type>::value);                      // constexpr since C++20
     104              :     explicit basic_string(const allocator_type& a);                                             // constexpr since C++20
     105              :     basic_string(const basic_string& str);                                                      // constexpr since C++20
     106              :     basic_string(basic_string&& str)
     107              :         noexcept(is_nothrow_move_constructible<allocator_type>::value);                         // constexpr since C++20
     108              :     basic_string(const basic_string& str, size_type pos,
     109              :                  const allocator_type& a = allocator_type());                                   // constexpr since C++20
     110              :     basic_string(const basic_string& str, size_type pos, size_type n,
     111              :                  const Allocator& a = Allocator());                                             // constexpr since C++20
     112              :     constexpr basic_string(
     113              :         basic_string&& str, size_type pos, const Allocator& a = Allocator());                   // since C++23
     114              :     constexpr basic_string(
     115              :         basic_string&& str, size_type pos, size_type n, const Allocator& a = Allocator());      // since C++23
     116              :     template<class T>
     117              :         basic_string(const T& t, size_type pos, size_type n, const Allocator& a = Allocator()); // C++17, constexpr since C++20
     118              :     template <class T>
     119              :         explicit basic_string(const T& t, const Allocator& a = Allocator());                    // C++17, constexpr since C++20
     120              :     basic_string(const value_type* s, const allocator_type& a = allocator_type());              // constexpr since C++20
     121              :     basic_string(const value_type* s, size_type n, const allocator_type& a = allocator_type()); // constexpr since C++20
     122              :     basic_string(nullptr_t) = delete; // C++2b
     123              :     basic_string(size_type n, value_type c, const allocator_type& a = allocator_type());        // constexpr since C++20
     124              :     template<class InputIterator>
     125              :         basic_string(InputIterator begin, InputIterator end,
     126              :                      const allocator_type& a = allocator_type());                               // constexpr since C++20
     127              :     basic_string(initializer_list<value_type>, const Allocator& = Allocator());                 // constexpr since C++20
     128              :     basic_string(const basic_string&, const Allocator&);                                        // constexpr since C++20
     129              :     basic_string(basic_string&&, const Allocator&);                                             // constexpr since C++20
     130              : 
     131              :     ~basic_string();                                                                            // constexpr since C++20
     132              : 
     133              :     operator basic_string_view<charT, traits>() const noexcept;                                 // constexpr since C++20
     134              : 
     135              :     basic_string& operator=(const basic_string& str);                                           // constexpr since C++20
     136              :     template <class T>
     137              :         basic_string& operator=(const T& t);                                                    // C++17, constexpr since C++20
     138              :     basic_string& operator=(basic_string&& str)
     139              :         noexcept(
     140              :              allocator_type::propagate_on_container_move_assignment::value ||
     141              :              allocator_type::is_always_equal::value );                                          // C++17, constexpr since C++20
     142              :     basic_string& operator=(const value_type* s);                                               // constexpr since C++20
     143              :     basic_string& operator=(nullptr_t) = delete; // C++2b
     144              :     basic_string& operator=(value_type c);                                                      // constexpr since C++20
     145              :     basic_string& operator=(initializer_list<value_type>);                                      // constexpr since C++20
     146              : 
     147              :     iterator       begin() noexcept;                                                            // constexpr since C++20
     148              :     const_iterator begin() const noexcept;                                                      // constexpr since C++20
     149              :     iterator       end() noexcept;                                                              // constexpr since C++20
     150              :     const_iterator end() const noexcept;                                                        // constexpr since C++20
     151              : 
     152              :     reverse_iterator       rbegin() noexcept;                                                   // constexpr since C++20
     153              :     const_reverse_iterator rbegin() const noexcept;                                             // constexpr since C++20
     154              :     reverse_iterator       rend() noexcept;                                                     // constexpr since C++20
     155              :     const_reverse_iterator rend() const noexcept;                                               // constexpr since C++20
     156              : 
     157              :     const_iterator         cbegin() const noexcept;                                             // constexpr since C++20
     158              :     const_iterator         cend() const noexcept;                                               // constexpr since C++20
     159              :     const_reverse_iterator crbegin() const noexcept;                                            // constexpr since C++20
     160              :     const_reverse_iterator crend() const noexcept;                                              // constexpr since C++20
     161              : 
     162              :     size_type size() const noexcept;                                                            // constexpr since C++20
     163              :     size_type length() const noexcept;                                                          // constexpr since C++20
     164              :     size_type max_size() const noexcept;                                                        // constexpr since C++20
     165              :     size_type capacity() const noexcept;                                                        // constexpr since C++20
     166              : 
     167              :     void resize(size_type n, value_type c);                                                     // constexpr since C++20
     168              :     void resize(size_type n);                                                                   // constexpr since C++20
     169              : 
     170              :     template<class Operation>
     171              :     constexpr void resize_and_overwrite(size_type n, Operation op); // since C++23
     172              : 
     173              :     void reserve(size_type res_arg);                                                            // constexpr since C++20
     174              :     void reserve(); // deprecated in C++20
     175              :     void shrink_to_fit();                                                                       // constexpr since C++20
     176              :     void clear() noexcept;                                                                      // constexpr since C++20
     177              :     bool empty() const noexcept;                                                                // constexpr since C++20
     178              : 
     179              :     const_reference operator[](size_type pos) const;                                            // constexpr since C++20
     180              :     reference       operator[](size_type pos);                                                  // constexpr since C++20
     181              : 
     182              :     const_reference at(size_type n) const;                                                      // constexpr since C++20
     183              :     reference       at(size_type n);                                                            // constexpr since C++20
     184              : 
     185              :     basic_string& operator+=(const basic_string& str);                                          // constexpr since C++20
     186              :     template <class T>
     187              :         basic_string& operator+=(const T& t);                                                   // C++17, constexpr since C++20
     188              :     basic_string& operator+=(const value_type* s);                                              // constexpr since C++20
     189              :     basic_string& operator+=(value_type c);                                                     // constexpr since C++20
     190              :     basic_string& operator+=(initializer_list<value_type>);                                     // constexpr since C++20
     191              : 
     192              :     basic_string& append(const basic_string& str);                                              // constexpr since C++20
     193              :     template <class T>
     194              :         basic_string& append(const T& t);                                                       // C++17, constexpr since C++20
     195              :     basic_string& append(const basic_string& str, size_type pos, size_type n=npos);             // C++14, constexpr since C++20
     196              :     template <class T>
     197              :         basic_string& append(const T& t, size_type pos, size_type n=npos);                      // C++17, constexpr since C++20
     198              :     basic_string& append(const value_type* s, size_type n);                                     // constexpr since C++20
     199              :     basic_string& append(const value_type* s);                                                  // constexpr since C++20
     200              :     basic_string& append(size_type n, value_type c);                                            // constexpr since C++20
     201              :     template<class InputIterator>
     202              :         basic_string& append(InputIterator first, InputIterator last);                          // constexpr since C++20
     203              :     basic_string& append(initializer_list<value_type>);                                         // constexpr since C++20
     204              : 
     205              :     void push_back(value_type c);                                                               // constexpr since C++20
     206              :     void pop_back();                                                                            // constexpr since C++20
     207              :     reference       front();                                                                    // constexpr since C++20
     208              :     const_reference front() const;                                                              // constexpr since C++20
     209              :     reference       back();                                                                     // constexpr since C++20
     210              :     const_reference back() const;                                                               // constexpr since C++20
     211              : 
     212              :     basic_string& assign(const basic_string& str);                                              // constexpr since C++20
     213              :     template <class T>
     214              :         basic_string& assign(const T& t);                                                       // C++17, constexpr since C++20
     215              :     basic_string& assign(basic_string&& str);                                                   // constexpr since C++20
     216              :     basic_string& assign(const basic_string& str, size_type pos, size_type n=npos);             // C++14, constexpr since C++20
     217              :     template <class T>
     218              :         basic_string& assign(const T& t, size_type pos, size_type n=npos);                      // C++17, constexpr since C++20
     219              :     basic_string& assign(const value_type* s, size_type n);                                     // constexpr since C++20
     220              :     basic_string& assign(const value_type* s);                                                  // constexpr since C++20
     221              :     basic_string& assign(size_type n, value_type c);                                            // constexpr since C++20
     222              :     template<class InputIterator>
     223              :         basic_string& assign(InputIterator first, InputIterator last);                          // constexpr since C++20
     224              :     basic_string& assign(initializer_list<value_type>);                                         // constexpr since C++20
     225              : 
     226              :     basic_string& insert(size_type pos1, const basic_string& str);                              // constexpr since C++20
     227              :     template <class T>
     228              :         basic_string& insert(size_type pos1, const T& t);                                       // constexpr since C++20
     229              :     basic_string& insert(size_type pos1, const basic_string& str,
     230              :                          size_type pos2, size_type n);                                          // constexpr since C++20
     231              :     template <class T>
     232              :         basic_string& insert(size_type pos1, const T& t, size_type pos2, size_type n);          // C++17, constexpr since C++20
     233              :     basic_string& insert(size_type pos, const value_type* s, size_type n=npos);                 // C++14, constexpr since C++20
     234              :     basic_string& insert(size_type pos, const value_type* s);                                   // constexpr since C++20
     235              :     basic_string& insert(size_type pos, size_type n, value_type c);                             // constexpr since C++20
     236              :     iterator      insert(const_iterator p, value_type c);                                       // constexpr since C++20
     237              :     iterator      insert(const_iterator p, size_type n, value_type c);                          // constexpr since C++20
     238              :     template<class InputIterator>
     239              :         iterator insert(const_iterator p, InputIterator first, InputIterator last);             // constexpr since C++20
     240              :     iterator      insert(const_iterator p, initializer_list<value_type>);                       // constexpr since C++20
     241              : 
     242              :     basic_string& erase(size_type pos = 0, size_type n = npos);                                 // constexpr since C++20
     243              :     iterator      erase(const_iterator position);                                               // constexpr since C++20
     244              :     iterator      erase(const_iterator first, const_iterator last);                             // constexpr since C++20
     245              : 
     246              :     basic_string& replace(size_type pos1, size_type n1, const basic_string& str);               // constexpr since C++20
     247              :     template <class T>
     248              :     basic_string& replace(size_type pos1, size_type n1, const T& t);                            // C++17, constexpr since C++20
     249              :     basic_string& replace(size_type pos1, size_type n1, const basic_string& str,
     250              :                           size_type pos2, size_type n2=npos);                                   // C++14, constexpr since C++20
     251              :     template <class T>
     252              :         basic_string& replace(size_type pos1, size_type n1, const T& t,
     253              :                               size_type pos2, size_type n);                                     // C++17, constexpr since C++20
     254              :     basic_string& replace(size_type pos, size_type n1, const value_type* s, size_type n2);      // constexpr since C++20
     255              :     basic_string& replace(size_type pos, size_type n1, const value_type* s);                    // constexpr since C++20
     256              :     basic_string& replace(size_type pos, size_type n1, size_type n2, value_type c);             // constexpr since C++20
     257              :     basic_string& replace(const_iterator i1, const_iterator i2, const basic_string& str);       // constexpr since C++20
     258              :     template <class T>
     259              :         basic_string& replace(const_iterator i1, const_iterator i2, const T& t);                // C++17, constexpr since C++20
     260              :     basic_string& replace(const_iterator i1, const_iterator i2, const value_type* s, size_type n); // constexpr since C++20
     261              :     basic_string& replace(const_iterator i1, const_iterator i2, const value_type* s);           // constexpr since C++20
     262              :     basic_string& replace(const_iterator i1, const_iterator i2, size_type n, value_type c);     // constexpr since C++20
     263              :     template<class InputIterator>
     264              :         basic_string& replace(const_iterator i1, const_iterator i2, InputIterator j1, InputIterator j2); // constexpr since C++20
     265              :     basic_string& replace(const_iterator i1, const_iterator i2, initializer_list<value_type>);  // constexpr since C++20
     266              : 
     267              :     size_type copy(value_type* s, size_type n, size_type pos = 0) const;                        // constexpr since C++20
     268              :     basic_string substr(size_type pos = 0, size_type n = npos) const;                           // constexpr in C++20, removed in C++23
     269              :     basic_string substr(size_type pos = 0, size_type n = npos) const&;                          // since C++23
     270              :     constexpr basic_string substr(size_type pos = 0, size_type n = npos) &&;                    // since C++23
     271              :     void swap(basic_string& str)
     272              :         noexcept(allocator_traits<allocator_type>::propagate_on_container_swap::value ||
     273              :                  allocator_traits<allocator_type>::is_always_equal::value);                     // C++17, constexpr since C++20
     274              : 
     275              :     const value_type* c_str() const noexcept;                                                   // constexpr since C++20
     276              :     const value_type* data() const noexcept;                                                    // constexpr since C++20
     277              :           value_type* data()       noexcept;                                                    // C++17, constexpr since C++20
     278              : 
     279              :     allocator_type get_allocator() const noexcept;                                              // constexpr since C++20
     280              : 
     281              :     size_type find(const basic_string& str, size_type pos = 0) const noexcept;                  // constexpr since C++20
     282              :     template <class T>
     283              :         size_type find(const T& t, size_type pos = 0) const noexcept;                           // C++17, noexcept as an extension, constexpr since C++20
     284              :     size_type find(const value_type* s, size_type pos, size_type n) const noexcept;             // constexpr since C++20
     285              :     size_type find(const value_type* s, size_type pos = 0) const noexcept;                      // constexpr since C++20
     286              :     size_type find(value_type c, size_type pos = 0) const noexcept;                             // constexpr since C++20
     287              : 
     288              :     size_type rfind(const basic_string& str, size_type pos = npos) const noexcept;              // constexpr since C++20
     289              :     template <class T>
     290              :         size_type rfind(const T& t, size_type pos = npos) const noexcept;                       // C++17, noexcept as an extension, constexpr since C++20
     291              :     size_type rfind(const value_type* s, size_type pos, size_type n) const noexcept;            // constexpr since C++20
     292              :     size_type rfind(const value_type* s, size_type pos = npos) const noexcept;                  // constexpr since C++20
     293              :     size_type rfind(value_type c, size_type pos = npos) const noexcept;                         // constexpr since C++20
     294              : 
     295              :     size_type find_first_of(const basic_string& str, size_type pos = 0) const noexcept;         // constexpr since C++20
     296              :     template <class T>
     297              :         size_type find_first_of(const T& t, size_type pos = 0) const noexcept;                  // C++17, noexcept as an extension, constexpr since C++20
     298              :     size_type find_first_of(const value_type* s, size_type pos, size_type n) const noexcept;    // constexpr since C++20
     299              :     size_type find_first_of(const value_type* s, size_type pos = 0) const noexcept;             // constexpr since C++20
     300              :     size_type find_first_of(value_type c, size_type pos = 0) const noexcept;                    // constexpr since C++20
     301              : 
     302              :     size_type find_last_of(const basic_string& str, size_type pos = npos) const noexcept;       // constexpr since C++20
     303              :     template <class T>
     304              :         size_type find_last_of(const T& t, size_type pos = npos) const noexcept noexcept;       // C++17, noexcept as an extension, constexpr since C++20
     305              :     size_type find_last_of(const value_type* s, size_type pos, size_type n) const noexcept;     // constexpr since C++20
     306              :     size_type find_last_of(const value_type* s, size_type pos = npos) const noexcept;           // constexpr since C++20
     307              :     size_type find_last_of(value_type c, size_type pos = npos) const noexcept;                  // constexpr since C++20
     308              : 
     309              :     size_type find_first_not_of(const basic_string& str, size_type pos = 0) const noexcept;     // constexpr since C++20
     310              :     template <class T>
     311              :         size_type find_first_not_of(const T& t, size_type pos = 0) const noexcept;              // C++17, noexcept as an extension, constexpr since C++20
     312              :     size_type find_first_not_of(const value_type* s, size_type pos, size_type n) const noexcept; // constexpr since C++20
     313              :     size_type find_first_not_of(const value_type* s, size_type pos = 0) const noexcept;         // constexpr since C++20
     314              :     size_type find_first_not_of(value_type c, size_type pos = 0) const noexcept;                // constexpr since C++20
     315              : 
     316              :     size_type find_last_not_of(const basic_string& str, size_type pos = npos) const noexcept;   // constexpr since C++20
     317              :     template <class T>
     318              :         size_type find_last_not_of(const T& t, size_type pos = npos) const noexcept;            // C++17, noexcept as an extension, constexpr since C++20
     319              :     size_type find_last_not_of(const value_type* s, size_type pos, size_type n) const noexcept; // constexpr since C++20
     320              :     size_type find_last_not_of(const value_type* s, size_type pos = npos) const noexcept;       // constexpr since C++20
     321              :     size_type find_last_not_of(value_type c, size_type pos = npos) const noexcept;              // constexpr since C++20
     322              : 
     323              :     int compare(const basic_string& str) const noexcept;                                        // constexpr since C++20
     324              :     template <class T>
     325              :         int compare(const T& t) const noexcept;                                                 // C++17, noexcept as an extension, constexpr since C++20
     326              :     int compare(size_type pos1, size_type n1, const basic_string& str) const;                   // constexpr since C++20
     327              :     template <class T>
     328              :         int compare(size_type pos1, size_type n1, const T& t) const;                            // C++17, constexpr since C++20
     329              :     int compare(size_type pos1, size_type n1, const basic_string& str,
     330              :                 size_type pos2, size_type n2=npos) const;                                       // C++14, constexpr since C++20
     331              :     template <class T>
     332              :         int compare(size_type pos1, size_type n1, const T& t,
     333              :                     size_type pos2, size_type n2=npos) const;                                   // C++17, constexpr since C++20
     334              :     int compare(const value_type* s) const noexcept;                                            // constexpr since C++20
     335              :     int compare(size_type pos1, size_type n1, const value_type* s) const;                       // constexpr since C++20
     336              :     int compare(size_type pos1, size_type n1, const value_type* s, size_type n2) const;         // constexpr since C++20
     337              : 
     338              :     constexpr bool starts_with(basic_string_view<charT, traits> sv) const noexcept;             // C++20
     339              :     constexpr bool starts_with(charT c) const noexcept;                                         // C++20
     340              :     constexpr bool starts_with(const charT* s) const;                                           // C++20
     341              :     constexpr bool ends_with(basic_string_view<charT, traits> sv) const noexcept;               // C++20
     342              :     constexpr bool ends_with(charT c) const noexcept;                                           // C++20
     343              :     constexpr bool ends_with(const charT* s) const;                                             // C++20
     344              : 
     345              :     constexpr bool contains(basic_string_view<charT, traits> sv) const noexcept;                // C++2b
     346              :     constexpr bool contains(charT c) const noexcept;                                            // C++2b
     347              :     constexpr bool contains(const charT* s) const;                                              // C++2b
     348              : };
     349              : 
     350              : template<class InputIterator,
     351              :          class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
     352              : basic_string(InputIterator, InputIterator, Allocator = Allocator())
     353              :    -> basic_string<typename iterator_traits<InputIterator>::value_type,
     354              :                   char_traits<typename iterator_traits<InputIterator>::value_type>,
     355              :                   Allocator>;   // C++17
     356              : 
     357              : template<class charT, class traits, class Allocator>
     358              : basic_string<charT, traits, Allocator>
     359              : operator+(const basic_string<charT, traits, Allocator>& lhs,
     360              :           const basic_string<charT, traits, Allocator>& rhs);                                   // constexpr since C++20
     361              : 
     362              : template<class charT, class traits, class Allocator>
     363              : basic_string<charT, traits, Allocator>
     364              : operator+(const charT* lhs , const basic_string<charT,traits,Allocator>&rhs);                   // constexpr since C++20
     365              : 
     366              : template<class charT, class traits, class Allocator>
     367              : basic_string<charT, traits, Allocator>
     368              : operator+(charT lhs, const basic_string<charT,traits,Allocator>& rhs);                          // constexpr since C++20
     369              : 
     370              : template<class charT, class traits, class Allocator>
     371              : basic_string<charT, traits, Allocator>
     372              : operator+(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);                 // constexpr since C++20
     373              : 
     374              : template<class charT, class traits, class Allocator>
     375              : basic_string<charT, traits, Allocator>
     376              : operator+(const basic_string<charT, traits, Allocator>& lhs, charT rhs);                        // constexpr since C++20
     377              : 
     378              : template<class charT, class traits, class Allocator>
     379              : bool operator==(const basic_string<charT, traits, Allocator>& lhs,
     380              :                 const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // constexpr since C++20
     381              : 
     382              : template<class charT, class traits, class Allocator>
     383              : bool operator==(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
     384              : 
     385              : template<class charT, class traits, class Allocator>
     386              : bool operator==(const basic_string<charT,traits,Allocator>& lhs, const charT* rhs) noexcept;    // constexpr since C++20
     387              : 
     388              : template<class charT, class traits, class Allocator>
     389              : bool operator!=(const basic_string<charT,traits,Allocator>& lhs,
     390              :                 const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // removed in C++20
     391              : 
     392              : template<class charT, class traits, class Allocator>
     393              : bool operator!=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
     394              : 
     395              : template<class charT, class traits, class Allocator>
     396              : bool operator!=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;  // removed in C++20
     397              : 
     398              : template<class charT, class traits, class Allocator>
     399              : bool operator< (const basic_string<charT, traits, Allocator>& lhs,
     400              :                 const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // removed in C++20
     401              : 
     402              : template<class charT, class traits, class Allocator>
     403              : bool operator< (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;  // removed in C++20
     404              : 
     405              : template<class charT, class traits, class Allocator>
     406              : bool operator< (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
     407              : 
     408              : template<class charT, class traits, class Allocator>
     409              : bool operator> (const basic_string<charT, traits, Allocator>& lhs,
     410              :                 const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // removed in C++20
     411              : 
     412              : template<class charT, class traits, class Allocator>
     413              : bool operator> (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;  // removed in C++20
     414              : 
     415              : template<class charT, class traits, class Allocator>
     416              : bool operator> (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
     417              : 
     418              : template<class charT, class traits, class Allocator>
     419              : bool operator<=(const basic_string<charT, traits, Allocator>& lhs,
     420              :                 const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // removed in C++20
     421              : 
     422              : template<class charT, class traits, class Allocator>
     423              : bool operator<=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;  // removed in C++20
     424              : 
     425              : template<class charT, class traits, class Allocator>
     426              : bool operator<=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
     427              : 
     428              : template<class charT, class traits, class Allocator>
     429              : bool operator>=(const basic_string<charT, traits, Allocator>& lhs,
     430              :                 const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // removed in C++20
     431              : 
     432              : template<class charT, class traits, class Allocator>
     433              : bool operator>=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;  // removed in C++20
     434              : 
     435              : template<class charT, class traits, class Allocator>
     436              : bool operator>=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
     437              : 
     438              : template<class charT, class traits, class Allocator>                                            // since C++20
     439              : constexpr see below operator<=>(const basic_string<charT, traits, Allocator>& lhs,
     440              :                                 const basic_string<charT, traits, Allocator>& rhs) noexcept;
     441              : 
     442              : template<class charT, class traits, class Allocator>                                            // since C++20
     443              : constexpr see below operator<=>(const basic_string<charT, traits, Allocator>& lhs,
     444              :                                 const charT* rhs) noexcept;
     445              : 
     446              : template<class charT, class traits, class Allocator>
     447              : void swap(basic_string<charT, traits, Allocator>& lhs,
     448              :           basic_string<charT, traits, Allocator>& rhs)
     449              :             noexcept(noexcept(lhs.swap(rhs)));                                                  // constexpr since C++20
     450              : 
     451              : template<class charT, class traits, class Allocator>
     452              : basic_istream<charT, traits>&
     453              : operator>>(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
     454              : 
     455              : template<class charT, class traits, class Allocator>
     456              : basic_ostream<charT, traits>&
     457              : operator<<(basic_ostream<charT, traits>& os, const basic_string<charT, traits, Allocator>& str);
     458              : 
     459              : template<class charT, class traits, class Allocator>
     460              : basic_istream<charT, traits>&
     461              : getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str,
     462              :         charT delim);
     463              : 
     464              : template<class charT, class traits, class Allocator>
     465              : basic_istream<charT, traits>&
     466              : getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
     467              : 
     468              : template<class charT, class traits, class Allocator, class U>
     469              : typename basic_string<charT, traits, Allocator>::size_type
     470              : erase(basic_string<charT, traits, Allocator>& c, const U& value);    // C++20
     471              : template<class charT, class traits, class Allocator, class Predicate>
     472              : typename basic_string<charT, traits, Allocator>::size_type
     473              : erase_if(basic_string<charT, traits, Allocator>& c, Predicate pred); // C++20
     474              : 
     475              : typedef basic_string<char>    string;
     476              : typedef basic_string<wchar_t> wstring;
     477              : typedef basic_string<char8_t> u8string; // C++20
     478              : typedef basic_string<char16_t> u16string;
     479              : typedef basic_string<char32_t> u32string;
     480              : 
     481              : int                stoi  (const string& str, size_t* idx = nullptr, int base = 10);
     482              : long               stol  (const string& str, size_t* idx = nullptr, int base = 10);
     483              : unsigned long      stoul (const string& str, size_t* idx = nullptr, int base = 10);
     484              : long long          stoll (const string& str, size_t* idx = nullptr, int base = 10);
     485              : unsigned long long stoull(const string& str, size_t* idx = nullptr, int base = 10);
     486              : 
     487              : float       stof (const string& str, size_t* idx = nullptr);
     488              : double      stod (const string& str, size_t* idx = nullptr);
     489              : long double stold(const string& str, size_t* idx = nullptr);
     490              : 
     491              : string to_string(int val);
     492              : string to_string(unsigned val);
     493              : string to_string(long val);
     494              : string to_string(unsigned long val);
     495              : string to_string(long long val);
     496              : string to_string(unsigned long long val);
     497              : string to_string(float val);
     498              : string to_string(double val);
     499              : string to_string(long double val);
     500              : 
     501              : int                stoi  (const wstring& str, size_t* idx = nullptr, int base = 10);
     502              : long               stol  (const wstring& str, size_t* idx = nullptr, int base = 10);
     503              : unsigned long      stoul (const wstring& str, size_t* idx = nullptr, int base = 10);
     504              : long long          stoll (const wstring& str, size_t* idx = nullptr, int base = 10);
     505              : unsigned long long stoull(const wstring& str, size_t* idx = nullptr, int base = 10);
     506              : 
     507              : float       stof (const wstring& str, size_t* idx = nullptr);
     508              : double      stod (const wstring& str, size_t* idx = nullptr);
     509              : long double stold(const wstring& str, size_t* idx = nullptr);
     510              : 
     511              : wstring to_wstring(int val);
     512              : wstring to_wstring(unsigned val);
     513              : wstring to_wstring(long val);
     514              : wstring to_wstring(unsigned long val);
     515              : wstring to_wstring(long long val);
     516              : wstring to_wstring(unsigned long long val);
     517              : wstring to_wstring(float val);
     518              : wstring to_wstring(double val);
     519              : wstring to_wstring(long double val);
     520              : 
     521              : template <> struct hash<string>;
     522              : template <> struct hash<u8string>; // C++20
     523              : template <> struct hash<u16string>;
     524              : template <> struct hash<u32string>;
     525              : template <> struct hash<wstring>;
     526              : 
     527              : basic_string<char>     operator "" s( const char *str,     size_t len );           // C++14, constexpr since C++20
     528              : basic_string<wchar_t>  operator "" s( const wchar_t *str,  size_t len );           // C++14, constexpr since C++20
     529              : constexpr basic_string<char8_t>  operator "" s( const char8_t *str,  size_t len ); // C++20
     530              : basic_string<char16_t> operator "" s( const char16_t *str, size_t len );           // C++14, constexpr since C++20
     531              : basic_string<char32_t> operator "" s( const char32_t *str, size_t len );           // C++14, constexpr since C++20
     532              : 
     533              : }  // std
     534              : 
     535              : */
     536              : 
     537              : #include <__algorithm/max.h>
     538              : #include <__algorithm/min.h>
     539              : #include <__algorithm/remove.h>
     540              : #include <__algorithm/remove_if.h>
     541              : #include <__assert> // all public C++ headers provide the assertion handler
     542              : #include <__config>
     543              : #include <__debug>
     544              : #include <__format/enable_insertable.h>
     545              : #include <__functional/hash.h>
     546              : #include <__functional/unary_function.h>
     547              : #include <__fwd/string.h>
     548              : #include <__ios/fpos.h>
     549              : #include <__iterator/distance.h>
     550              : #include <__iterator/iterator_traits.h>
     551              : #include <__iterator/reverse_iterator.h>
     552              : #include <__iterator/wrap_iter.h>
     553              : #include <__memory/allocate_at_least.h>
     554              : #include <__memory/allocator.h>
     555              : #include <__memory/allocator_traits.h>
     556              : #include <__memory/compressed_pair.h>
     557              : #include <__memory/construct_at.h>
     558              : #include <__memory/pointer_traits.h>
     559              : #include <__memory/swap_allocator.h>
     560              : #include <__memory_resource/polymorphic_allocator.h>
     561              : #include <__string/char_traits.h>
     562              : #include <__string/extern_template_lists.h>
     563              : #include <__type_traits/is_allocator.h>
     564              : #include <__type_traits/noexcept_move_assign_container.h>
     565              : #include <__utility/auto_cast.h>
     566              : #include <__utility/move.h>
     567              : #include <__utility/swap.h>
     568              : #include <__utility/unreachable.h>
     569              : #include <climits>
     570              : #include <cstdint>
     571              : #include <cstdio>  // EOF
     572              : #include <cstdlib>
     573              : #include <cstring>
     574              : #include <limits>
     575              : #include <stdexcept>
     576              : #include <string_view>
     577              : #include <type_traits>
     578              : #include <version>
     579              : 
     580              : #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
     581              : #  include <cwchar>
     582              : #endif
     583              : 
     584              : // standard-mandated includes
     585              : 
     586              : // [iterator.range]
     587              : #include <__iterator/access.h>
     588              : #include <__iterator/data.h>
     589              : #include <__iterator/empty.h>
     590              : #include <__iterator/reverse_access.h>
     591              : #include <__iterator/size.h>
     592              : 
     593              : // [string.syn]
     594              : #include <compare>
     595              : #include <initializer_list>
     596              : 
     597              : #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
     598              : #  pragma GCC system_header
     599              : #endif
     600              : 
     601              : _LIBCPP_PUSH_MACROS
     602              : #include <__undef_macros>
     603              : 
     604              : 
     605              : _LIBCPP_BEGIN_NAMESPACE_STD
     606              : 
     607              : // basic_string
     608              : 
     609              : template<class _CharT, class _Traits, class _Allocator>
     610              : basic_string<_CharT, _Traits, _Allocator>
     611              : _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     612              : operator+(const basic_string<_CharT, _Traits, _Allocator>& __x,
     613              :           const basic_string<_CharT, _Traits, _Allocator>& __y);
     614              : 
     615              : template<class _CharT, class _Traits, class _Allocator>
     616              : _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20
     617              : basic_string<_CharT, _Traits, _Allocator>
     618              : operator+(const _CharT* __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
     619              : 
     620              : template<class _CharT, class _Traits, class _Allocator>
     621              : _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     622              : basic_string<_CharT, _Traits, _Allocator>
     623              : operator+(_CharT __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
     624              : 
     625              : template<class _CharT, class _Traits, class _Allocator>
     626              : inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     627              : basic_string<_CharT, _Traits, _Allocator>
     628              : operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, const _CharT* __y);
     629              : 
     630              : template<class _CharT, class _Traits, class _Allocator>
     631              : _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     632              : basic_string<_CharT, _Traits, _Allocator>
     633              : operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, _CharT __y);
     634              : 
     635              : extern template _LIBCPP_FUNC_VIS string operator+<char, char_traits<char>, allocator<char> >(char const*, string const&);
     636              : 
     637              : template <class _Iter>
     638              : struct __string_is_trivial_iterator : public false_type {};
     639              : 
     640              : template <class _Tp>
     641              : struct __string_is_trivial_iterator<_Tp*>
     642              :     : public is_arithmetic<_Tp> {};
     643              : 
     644              : template <class _Iter>
     645              : struct __string_is_trivial_iterator<__wrap_iter<_Iter> >
     646              :     : public __string_is_trivial_iterator<_Iter> {};
     647              : 
     648              : template <class _CharT, class _Traits, class _Tp>
     649              : struct __can_be_converted_to_string_view : public _BoolConstant<
     650              :       is_convertible<const _Tp&, basic_string_view<_CharT, _Traits> >::value &&
     651              :      !is_convertible<const _Tp&, const _CharT*>::value
     652              :     > {};
     653              : 
     654              : struct __uninitialized_size_tag {};
     655              : 
     656              : template<class _CharT, class _Traits, class _Allocator>
     657              : class basic_string
     658              : {
     659              : public:
     660              :     typedef basic_string                                 __self;
     661              :     typedef basic_string_view<_CharT, _Traits>           __self_view;
     662              :     typedef _Traits                                      traits_type;
     663              :     typedef _CharT                                       value_type;
     664              :     typedef _Allocator                                   allocator_type;
     665              :     typedef allocator_traits<allocator_type>             __alloc_traits;
     666              :     typedef typename __alloc_traits::size_type           size_type;
     667              :     typedef typename __alloc_traits::difference_type     difference_type;
     668              :     typedef value_type&                                  reference;
     669              :     typedef const value_type&                            const_reference;
     670              :     typedef typename __alloc_traits::pointer             pointer;
     671              :     typedef typename __alloc_traits::const_pointer       const_pointer;
     672              : 
     673              :     static_assert((!is_array<value_type>::value), "Character type of basic_string must not be an array");
     674              :     static_assert(( is_standard_layout<value_type>::value), "Character type of basic_string must be standard-layout");
     675              :     static_assert(( is_trivial<value_type>::value), "Character type of basic_string must be trivial");
     676              :     static_assert(( is_same<_CharT, typename traits_type::char_type>::value),
     677              :                   "traits_type::char_type must be the same type as CharT");
     678              :     static_assert(( is_same<typename allocator_type::value_type, value_type>::value),
     679              :                   "Allocator::value_type must be same type as value_type");
     680              : 
     681              :     static_assert(is_same<allocator_type, __rebind_alloc<__alloc_traits, value_type> >::value,
     682              :                   "[allocator.requirements] states that rebinding an allocator to the same type should result in the "
     683              :                   "original allocator");
     684              : 
     685              :     // TODO: Implement iterator bounds checking without requiring the global database.
     686              :     typedef __wrap_iter<pointer>                         iterator;
     687              :     typedef __wrap_iter<const_pointer>                   const_iterator;
     688              :     typedef std::reverse_iterator<iterator>              reverse_iterator;
     689              :     typedef std::reverse_iterator<const_iterator>        const_reverse_iterator;
     690              : 
     691              : private:
     692              :     static_assert(CHAR_BIT == 8, "This implementation assumes that one byte contains 8 bits");
     693              : 
     694              : #ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
     695              : 
     696              :     struct __long
     697              :     {
     698              :         pointer   __data_;
     699              :         size_type __size_;
     700              :         size_type __cap_ : sizeof(size_type) * CHAR_BIT - 1;
     701              :         size_type __is_long_ : 1;
     702              :     };
     703              : 
     704              :     enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
     705              :                       (sizeof(__long) - 1)/sizeof(value_type) : 2};
     706              : 
     707              :     struct __short
     708              :     {
     709              :         value_type __data_[__min_cap];
     710              :         unsigned char __padding_[sizeof(value_type) - 1];
     711              :         unsigned char __size_ : 7;
     712              :         unsigned char __is_long_ : 1;
     713              :     };
     714              : 
     715              : // The __endian_factor is required because the field we use to store the size
     716              : // has one fewer bit than it would if it were not a bitfield.
     717              : //
     718              : // If the LSB is used to store the short-flag in the short string representation,
     719              : // we have to multiply the size by two when it is stored and divide it by two when
     720              : // it is loaded to make sure that we always store an even number. In the long string
     721              : // representation, we can ignore this because we can assume that we always allocate
     722              : // an even amount of value_types.
     723              : //
     724              : // If the MSB is used for the short-flag, the max_size() is numeric_limits<size_type>::max() / 2.
     725              : // This does not impact the short string representation, since we never need the MSB
     726              : // for representing the size of a short string anyway.
     727              : 
     728              : #ifdef _LIBCPP_BIG_ENDIAN
     729              :     static const size_type __endian_factor = 2;
     730              : #else
     731              :     static const size_type __endian_factor = 1;
     732              : #endif
     733              : 
     734              : #else // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
     735              : 
     736              : #ifdef _LIBCPP_BIG_ENDIAN
     737              :     static const size_type __endian_factor = 1;
     738              : #else
     739              :     static const size_type __endian_factor = 2;
     740              : #endif
     741              : 
     742              :     // Attribute 'packed' is used to keep the layout compatible with the
     743              :     // previous definition that did not use bit fields. This is because on
     744              :     // some platforms bit fields have a default size rather than the actual
     745              :     // size used, e.g., it is 4 bytes on AIX. See D128285 for details.
     746              :     struct __long
     747              :     {
     748              :         struct _LIBCPP_PACKED {
     749              :             size_type __is_long_ : 1;
     750              :             size_type __cap_ : sizeof(size_type) * CHAR_BIT - 1;
     751              :         };
     752              :         size_type __size_;
     753              :         pointer   __data_;
     754              :     };
     755              : 
     756              :     enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
     757              :                       (sizeof(__long) - 1)/sizeof(value_type) : 2};
     758              : 
     759              :     struct __short
     760              :     {
     761              :         struct _LIBCPP_PACKED {
     762              :             unsigned char __is_long_ : 1;
     763              :             unsigned char __size_ : 7;
     764              :         };
     765              :         char __padding_[sizeof(value_type) - 1];
     766              :         value_type __data_[__min_cap];
     767              :     };
     768              : 
     769              : #endif // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
     770              : 
     771              :     static_assert(sizeof(__short) == (sizeof(value_type) * (__min_cap + 1)), "__short has an unexpected size.");
     772              : 
     773              :     union __ulx{__long __lx; __short __lxx;};
     774              : 
     775              :     enum {__n_words = sizeof(__ulx) / sizeof(size_type)};
     776              : 
     777              :     struct __raw
     778              :     {
     779              :         size_type __words[__n_words];
     780              :     };
     781              : 
     782              :     struct __rep
     783              :     {
     784              :         union
     785              :         {
     786              :             __long  __l;
     787              :             __short __s;
     788              :             __raw   __r;
     789              :         };
     790              :     };
     791              : 
     792              :     __compressed_pair<__rep, allocator_type> __r_;
     793              : 
     794              :     // Construct a string with the given allocator and enough storage to hold `__size` characters, but
     795              :     // don't initialize the characters. The contents of the string, including the null terminator, must be
     796              :     // initialized separately.
     797              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     798              :     explicit basic_string(__uninitialized_size_tag, size_type __size, const allocator_type& __a)
     799              :             : __r_(__default_init_tag(), __a) {
     800              :         if (__size > max_size())
     801              :             __throw_length_error();
     802              :         if (__fits_in_sso(__size)) {
     803              :             __r_.first() = __rep();
     804              :             __set_short_size(__size);
     805              :         } else {
     806              :             auto __capacity = __recommend(__size) + 1;
     807              :             auto __allocation = __alloc_traits::allocate(__alloc(), __capacity);
     808              :             __begin_lifetime(__allocation, __capacity);
     809              :             __set_long_cap(__capacity);
     810              :             __set_long_pointer(__allocation);
     811              :             __set_long_size(__size);
     812              :         }
     813              :         std::__debug_db_insert_c(this);
     814              :     }
     815              : 
     816        22262 :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator __make_iterator(pointer __p) {
     817        22262 :         return iterator(this, __p);
     818              :     }
     819              : 
     820              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_iterator __make_const_iterator(const_pointer __p) const {
     821              :         return const_iterator(this, __p);
     822              :     }
     823              : 
     824              : public:
     825              :   _LIBCPP_TEMPLATE_DATA_VIS static const size_type npos = -1;
     826              : 
     827        16602 :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string()
     828              :       _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
     829        16602 :       : __r_(__default_init_tag(), __default_init_tag()) {
     830         8301 :     std::__debug_db_insert_c(this);
     831         8301 :     __default_init();
     832        16602 :   }
     833              : 
     834              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(const allocator_type& __a)
     835              : #if _LIBCPP_STD_VER <= 14
     836              :       _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
     837              : #else
     838              :       _NOEXCEPT
     839              : #endif
     840              :       : __r_(__default_init_tag(), __a) {
     841              :     std::__debug_db_insert_c(this);
     842              :     __default_init();
     843              :   }
     844              : 
     845              :   _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(const basic_string& __str);
     846              :   _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(const basic_string& __str, const allocator_type& __a);
     847              : 
     848              : #ifndef _LIBCPP_CXX03_LANG
     849              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(basic_string&& __str)
     850              : #  if _LIBCPP_STD_VER <= 14
     851              :       _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
     852              : #  else
     853              :       _NOEXCEPT
     854              : #  endif
     855              :       : __r_(std::move(__str.__r_)) {
     856              :     __str.__default_init();
     857              :     std::__debug_db_insert_c(this);
     858              :     if (__is_long())
     859              :       std::__debug_db_swap(this, &__str);
     860              :   }
     861              : 
     862              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(basic_string&& __str, const allocator_type& __a)
     863              :       : __r_(__default_init_tag(), __a) {
     864              :     if (__str.__is_long() && __a != __str.__alloc()) // copy, not move
     865              :       __init(std::__to_address(__str.__get_long_pointer()), __str.__get_long_size());
     866              :     else {
     867              :       if (__libcpp_is_constant_evaluated())
     868              :         __r_.first() = __rep();
     869              :       __r_.first() = __str.__r_.first();
     870              :       __str.__default_init();
     871              :     }
     872              :     std::__debug_db_insert_c(this);
     873              :     if (__is_long())
     874              :       std::__debug_db_swap(this, &__str);
     875              :   }
     876              : #endif // _LIBCPP_CXX03_LANG
     877              : 
     878              :   template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
     879         1658 :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(const _CharT* __s)
     880         1658 :       : __r_(__default_init_tag(), __default_init_tag()) {
     881          829 :     _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*) detected nullptr");
     882          829 :     __init(__s, traits_type::length(__s));
     883          829 :     std::__debug_db_insert_c(this);
     884         1658 :   }
     885              : 
     886              :   template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
     887              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(const _CharT* __s, const _Allocator& __a);
     888              : 
     889              : #if _LIBCPP_STD_VER > 20
     890              :   basic_string(nullptr_t) = delete;
     891              : #endif
     892              : 
     893              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(const _CharT* __s, size_type __n)
     894              :       : __r_(__default_init_tag(), __default_init_tag()) {
     895              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n) detected nullptr");
     896              :     __init(__s, __n);
     897              :     std::__debug_db_insert_c(this);
     898              :   }
     899              : 
     900              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     901              :   basic_string(const _CharT* __s, size_type __n, const _Allocator& __a)
     902              :       : __r_(__default_init_tag(), __a) {
     903              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n, allocator) detected nullptr");
     904              :     __init(__s, __n);
     905              :     std::__debug_db_insert_c(this);
     906              :   }
     907              : 
     908            0 :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(size_type __n, _CharT __c)
     909            0 :       : __r_(__default_init_tag(), __default_init_tag()) {
     910            0 :     __init(__n, __c);
     911            0 :     std::__debug_db_insert_c(this);
     912            0 :   }
     913              : 
     914              : #if _LIBCPP_STD_VER > 20
     915              :   _LIBCPP_HIDE_FROM_ABI constexpr
     916              :   basic_string(basic_string&& __str, size_type __pos, const _Allocator& __alloc = _Allocator())
     917              :       : basic_string(std::move(__str), __pos, npos, __alloc) {}
     918              : 
     919              :   _LIBCPP_HIDE_FROM_ABI constexpr
     920              :   basic_string(basic_string&& __str, size_type __pos, size_type __n, const _Allocator& __alloc = _Allocator())
     921              :       : __r_(__default_init_tag(), __alloc) {
     922              :     if (__pos > __str.size())
     923              :       __throw_out_of_range();
     924              : 
     925              :     auto __len = std::min<size_type>(__n, __str.size() - __pos);
     926              :     if (__alloc_traits::is_always_equal::value || __alloc == __str.__alloc()) {
     927              :       __r_.first() = __str.__r_.first();
     928              :       __str.__default_init();
     929              : 
     930              :       _Traits::move(data(), data() + __pos, __len);
     931              :       __set_size(__len);
     932              :       _Traits::assign(data()[__len], value_type());
     933              :     } else {
     934              :       // Perform a copy because the allocators are not compatible.
     935              :       __init(__str.data() + __pos, __len);
     936              :     }
     937              : 
     938              :     std::__debug_db_insert_c(this);
     939              :     if (__is_long())
     940              :       std::__debug_db_swap(this, &__str);
     941              :   }
     942              : #endif
     943              : 
     944              :   template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
     945              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(size_type __n, _CharT __c, const _Allocator& __a);
     946              : 
     947              :   _LIBCPP_CONSTEXPR_SINCE_CXX20
     948              :   basic_string(const basic_string& __str, size_type __pos, size_type __n, const _Allocator& __a = _Allocator());
     949              : 
     950              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     951              :   basic_string(const basic_string& __str, size_type __pos, const _Allocator& __a = _Allocator())
     952              :       : __r_(__default_init_tag(), __a) {
     953              :     size_type __str_sz = __str.size();
     954              :     if (__pos > __str_sz)
     955              :       __throw_out_of_range();
     956              :     __init(__str.data() + __pos, __str_sz - __pos);
     957              :     std::__debug_db_insert_c(this);
     958              :   }
     959              : 
     960              :   template <class _Tp,
     961              :             class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
     962              :                                   !__is_same_uncvref<_Tp, basic_string>::value> >
     963              :   _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
     964              :   basic_string(const _Tp& __t, size_type __pos, size_type __n, const allocator_type& __a = allocator_type());
     965              : 
     966              :   template <class _Tp,
     967              :             class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
     968              :                                   !__is_same_uncvref<_Tp, basic_string>::value> >
     969              :   _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(
     970              :       const _Tp& __t);
     971              : 
     972              :   template <class _Tp,
     973              :             class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
     974              :                                   !__is_same_uncvref<_Tp, basic_string>::value> >
     975              :   _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(
     976              :       const _Tp& __t, const allocator_type& __a);
     977              : 
     978              :   template <class _InputIterator, class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value> >
     979              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(_InputIterator __first, _InputIterator __last)
     980              :       : __r_(__default_init_tag(), __default_init_tag()) {
     981              :     __init(__first, __last);
     982              :     std::__debug_db_insert_c(this);
     983              :   }
     984              : 
     985              :   template <class _InputIterator, class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value> >
     986              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     987              :   basic_string(_InputIterator __first, _InputIterator __last, const allocator_type& __a)
     988              :       : __r_(__default_init_tag(), __a) {
     989              :     __init(__first, __last);
     990              :     std::__debug_db_insert_c(this);
     991              :   }
     992              : 
     993              : #ifndef _LIBCPP_CXX03_LANG
     994              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(initializer_list<_CharT> __il)
     995              :       : __r_(__default_init_tag(), __default_init_tag()) {
     996              :     __init(__il.begin(), __il.end());
     997              :     std::__debug_db_insert_c(this);
     998              :   }
     999              : 
    1000              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(initializer_list<_CharT> __il, const _Allocator& __a)
    1001              :       : __r_(__default_init_tag(), __a) {
    1002              :     __init(__il.begin(), __il.end());
    1003              :     std::__debug_db_insert_c(this);
    1004              :   }
    1005              : #endif // _LIBCPP_CXX03_LANG
    1006              : 
    1007              :     inline _LIBCPP_CONSTEXPR_SINCE_CXX20 ~basic_string();
    1008              : 
    1009              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1010        13543 :     operator __self_view() const _NOEXCEPT { return __self_view(data(), size()); }
    1011              : 
    1012              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator=(const basic_string& __str);
    1013              : 
    1014              :     template <class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
    1015              :                                                !__is_same_uncvref<_Tp, basic_string>::value> >
    1016              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator=(const _Tp& __t) {
    1017              :       __self_view __sv = __t;
    1018              :       return assign(__sv);
    1019              :     }
    1020              : 
    1021              : #ifndef _LIBCPP_CXX03_LANG
    1022              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator=(basic_string&& __str)
    1023              :       _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value)) {
    1024              :     __move_assign(__str, integral_constant<bool, __alloc_traits::propagate_on_container_move_assignment::value>());
    1025              :     return *this;
    1026              :   }
    1027              : 
    1028              :      _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1029              :     basic_string& operator=(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
    1030              : #endif
    1031              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1032            6 :     basic_string& operator=(const value_type* __s) {return assign(__s);}
    1033              : #if _LIBCPP_STD_VER > 20
    1034              :     basic_string& operator=(nullptr_t) = delete;
    1035              : #endif
    1036              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator=(value_type __c);
    1037              : 
    1038              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1039         2082 :     iterator begin() _NOEXCEPT
    1040         2082 :         {return __make_iterator(__get_pointer());}
    1041              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1042              :     const_iterator begin() const _NOEXCEPT
    1043              :         {return __make_const_iterator(__get_pointer());}
    1044              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1045        20180 :     iterator end() _NOEXCEPT
    1046        20180 :         {return __make_iterator(__get_pointer() + size());}
    1047              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1048              :     const_iterator end() const _NOEXCEPT
    1049              :         {return __make_const_iterator(__get_pointer() + size());}
    1050              : 
    1051              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1052              :     reverse_iterator rbegin() _NOEXCEPT
    1053              :         {return reverse_iterator(end());}
    1054              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1055              :     const_reverse_iterator rbegin() const _NOEXCEPT
    1056              :         {return const_reverse_iterator(end());}
    1057              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1058              :     reverse_iterator rend() _NOEXCEPT
    1059              :         {return reverse_iterator(begin());}
    1060              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1061              :     const_reverse_iterator rend() const _NOEXCEPT
    1062              :         {return const_reverse_iterator(begin());}
    1063              : 
    1064              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1065              :     const_iterator cbegin() const _NOEXCEPT
    1066              :         {return begin();}
    1067              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1068              :     const_iterator cend() const _NOEXCEPT
    1069              :         {return end();}
    1070              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1071              :     const_reverse_iterator crbegin() const _NOEXCEPT
    1072              :         {return rbegin();}
    1073              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1074              :     const_reverse_iterator crend() const _NOEXCEPT
    1075              :         {return rend();}
    1076              : 
    1077       125782 :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type size() const _NOEXCEPT
    1078       125782 :         {return __is_long() ? __get_long_size() : __get_short_size();}
    1079              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type length() const _NOEXCEPT {return size();}
    1080              : 
    1081        36845 :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type max_size() const _NOEXCEPT {
    1082        36845 :     size_type __m = __alloc_traits::max_size(__alloc());
    1083        36845 :     if (__m <= std::numeric_limits<size_type>::max() / 2) {
    1084            0 :       return __m - __alignment;
    1085              :     } else {
    1086        36845 :     bool __uses_lsb = __endian_factor == 2;
    1087        36845 :       return __uses_lsb ? __m - __alignment : (__m / 2) - __alignment;
    1088              :     }
    1089        36845 :   }
    1090              : 
    1091              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type capacity() const _NOEXCEPT {
    1092              :         return (__is_long() ? __get_long_cap() : static_cast<size_type>(__min_cap)) - 1;
    1093              :     }
    1094              : 
    1095              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 void resize(size_type __n, value_type __c);
    1096              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void resize(size_type __n) { resize(__n, value_type()); }
    1097              : 
    1098              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 void reserve(size_type __requested_capacity);
    1099              : 
    1100              : #if _LIBCPP_STD_VER > 20
    1101              :     template <class _Op>
    1102              :     _LIBCPP_HIDE_FROM_ABI constexpr
    1103              :     void resize_and_overwrite(size_type __n, _Op __op) {
    1104              :       __resize_default_init(__n);
    1105              :       __erase_to_end(std::move(__op)(data(), _LIBCPP_AUTO_CAST(__n)));
    1106              :     }
    1107              : #endif
    1108              : 
    1109              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __resize_default_init(size_type __n);
    1110              : 
    1111              :     _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_HIDE_FROM_ABI void reserve() _NOEXCEPT { shrink_to_fit(); }
    1112              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void shrink_to_fit() _NOEXCEPT;
    1113              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void clear() _NOEXCEPT;
    1114              : 
    1115              :     _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1116         2082 :     bool empty() const _NOEXCEPT {return size() == 0;}
    1117              : 
    1118              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference operator[](size_type __pos) const _NOEXCEPT {
    1119              :     _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
    1120              :     return *(data() + __pos);
    1121              :   }
    1122              : 
    1123              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference operator[](size_type __pos) _NOEXCEPT {
    1124              :     _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
    1125              :     return *(__get_pointer() + __pos);
    1126              :   }
    1127              : 
    1128              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference at(size_type __n) const;
    1129              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 reference       at(size_type __n);
    1130              : 
    1131              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator+=(const basic_string& __str) {
    1132              :         return append(__str);
    1133              :     }
    1134              : 
    1135              :     template <class _Tp>
    1136              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1137              :     __enable_if_t
    1138              :         <
    1139              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
    1140              :             && !__is_same_uncvref<_Tp, basic_string >::value,
    1141              :             basic_string&
    1142              :         >
    1143              :     operator+=(const _Tp& __t) {
    1144              :         __self_view __sv = __t; return append(__sv);
    1145              :     }
    1146              : 
    1147              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator+=(const value_type* __s) {
    1148              :         return append(__s);
    1149              :     }
    1150              : 
    1151              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator+=(value_type __c) {
    1152              :         push_back(__c);
    1153              :         return *this;
    1154              :     }
    1155              : 
    1156              : #ifndef _LIBCPP_CXX03_LANG
    1157              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1158              :     basic_string& operator+=(initializer_list<value_type> __il) { return append(__il); }
    1159              : #endif // _LIBCPP_CXX03_LANG
    1160              : 
    1161              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const basic_string& __str) {
    1162              :         return append(__str.data(), __str.size());
    1163              :   }
    1164              : 
    1165              :     template <class _Tp>
    1166              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1167              :     __enable_if_t<
    1168              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
    1169              :             && !__is_same_uncvref<_Tp, basic_string>::value,
    1170              :             basic_string&
    1171              :         >
    1172              :                   append(const _Tp& __t) { __self_view __sv = __t; return append(__sv.data(), __sv.size()); }
    1173              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const basic_string& __str, size_type __pos, size_type __n=npos);
    1174              : 
    1175              :     template <class _Tp>
    1176              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1177              :     __enable_if_t
    1178              :         <
    1179              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
    1180              :             && !__is_same_uncvref<_Tp, basic_string>::value,
    1181              :             basic_string&
    1182              :         >
    1183              :                   append(const _Tp& __t, size_type __pos, size_type __n=npos);
    1184              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const value_type* __s, size_type __n);
    1185              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const value_type* __s);
    1186              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(size_type __n, value_type __c);
    1187              : 
    1188              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1189              :     void __append_default_init(size_type __n);
    1190              : 
    1191              :     template<class _InputIterator>
    1192              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
    1193              :     __enable_if_t
    1194              :         <
    1195              :             __is_exactly_cpp17_input_iterator<_InputIterator>::value,
    1196              :             basic_string&
    1197              :         >
    1198              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1199              :     append(_InputIterator __first, _InputIterator __last) {
    1200              :       const basic_string __temp(__first, __last, __alloc());
    1201              :       append(__temp.data(), __temp.size());
    1202              :       return *this;
    1203              :     }
    1204              :     template<class _ForwardIterator>
    1205              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
    1206              :     __enable_if_t
    1207              :         <
    1208              :             __is_cpp17_forward_iterator<_ForwardIterator>::value,
    1209              :             basic_string&
    1210              :         >
    1211              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1212              :     append(_ForwardIterator __first, _ForwardIterator __last);
    1213              : 
    1214              : #ifndef _LIBCPP_CXX03_LANG
    1215              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1216              :     basic_string& append(initializer_list<value_type> __il) {return append(__il.begin(), __il.size());}
    1217              : #endif // _LIBCPP_CXX03_LANG
    1218              : 
    1219              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 void push_back(value_type __c);
    1220              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void pop_back();
    1221              : 
    1222              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference front() _NOEXCEPT {
    1223              :     _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
    1224              :     return *__get_pointer();
    1225              :   }
    1226              : 
    1227              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference front() const _NOEXCEPT {
    1228              :     _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
    1229              :     return *data();
    1230              :   }
    1231              : 
    1232              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference back() _NOEXCEPT {
    1233              :     _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
    1234              :     return *(__get_pointer() + size() - 1);
    1235              :   }
    1236              : 
    1237              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference back() const _NOEXCEPT {
    1238              :     _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
    1239              :     return *(data() + size() - 1);
    1240              :   }
    1241              : 
    1242              :     template <class _Tp>
    1243              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1244              :     __enable_if_t
    1245              :         <
    1246              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1247              :             basic_string&
    1248              :         >
    1249              :                  assign(const _Tp & __t) { __self_view __sv = __t; return assign(__sv.data(), __sv.size()); }
    1250              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1251              :     basic_string& assign(const basic_string& __str) { return *this = __str; }
    1252              : #ifndef _LIBCPP_CXX03_LANG
    1253              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1254              :     basic_string& assign(basic_string&& __str)
    1255              :         _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
    1256              :         {*this = std::move(__str); return *this;}
    1257              : #endif
    1258              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(const basic_string& __str, size_type __pos, size_type __n=npos);
    1259              :     template <class _Tp>
    1260              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1261              :     __enable_if_t
    1262              :         <
    1263              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
    1264              :             && !__is_same_uncvref<_Tp, basic_string>::value,
    1265              :             basic_string&
    1266              :         >
    1267              :                   assign(const _Tp & __t, size_type __pos, size_type __n=npos);
    1268              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(const value_type* __s, size_type __n);
    1269              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(const value_type* __s);
    1270              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(size_type __n, value_type __c);
    1271              :     template<class _InputIterator>
    1272              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1273              :     __enable_if_t
    1274              :         <
    1275              :             __is_exactly_cpp17_input_iterator<_InputIterator>::value,
    1276              :             basic_string&
    1277              :         >
    1278              :         assign(_InputIterator __first, _InputIterator __last);
    1279              :     template<class _ForwardIterator>
    1280              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1281              :     __enable_if_t
    1282              :         <
    1283              :             __is_cpp17_forward_iterator<_ForwardIterator>::value,
    1284              :             basic_string&
    1285              :         >
    1286              :         assign(_ForwardIterator __first, _ForwardIterator __last);
    1287              : #ifndef _LIBCPP_CXX03_LANG
    1288              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1289              :     basic_string& assign(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
    1290              : #endif // _LIBCPP_CXX03_LANG
    1291              : 
    1292              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
    1293              :   insert(size_type __pos1, const basic_string& __str) {
    1294              :     return insert(__pos1, __str.data(), __str.size());
    1295              :   }
    1296              : 
    1297              :     template <class _Tp>
    1298              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1299              :     __enable_if_t
    1300              :         <
    1301              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1302              :             basic_string&
    1303              :         >
    1304              :                  insert(size_type __pos1, const _Tp& __t)
    1305              :     { __self_view __sv = __t; return insert(__pos1, __sv.data(), __sv.size()); }
    1306              : 
    1307              :     template <class _Tp>
    1308              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1309              :     __enable_if_t
    1310              :         <
    1311              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value && !__is_same_uncvref<_Tp, basic_string>::value,
    1312              :             basic_string&
    1313              :         >
    1314              :                   insert(size_type __pos1, const _Tp& __t, size_type __pos2, size_type __n=npos);
    1315              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1316              :     basic_string& insert(size_type __pos1, const basic_string& __str, size_type __pos2, size_type __n=npos);
    1317              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& insert(size_type __pos, const value_type* __s, size_type __n);
    1318              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& insert(size_type __pos, const value_type* __s);
    1319              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& insert(size_type __pos, size_type __n, value_type __c);
    1320              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator      insert(const_iterator __pos, value_type __c);
    1321              : 
    1322              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator
    1323              :   insert(const_iterator __pos, size_type __n, value_type __c) {
    1324              :     _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
    1325              :                          "string::insert(iterator, n, value) called with an iterator not referring to this string");
    1326              :     difference_type __p = __pos - begin();
    1327              :     insert(static_cast<size_type>(__p), __n, __c);
    1328              :     return begin() + __p;
    1329              :   }
    1330              : 
    1331              :     template<class _InputIterator>
    1332              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1333              :     __enable_if_t
    1334              :         <
    1335              :             __is_exactly_cpp17_input_iterator<_InputIterator>::value,
    1336              :             iterator
    1337              :         >
    1338              :         insert(const_iterator __pos, _InputIterator __first, _InputIterator __last);
    1339              :     template<class _ForwardIterator>
    1340              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1341              :     __enable_if_t
    1342              :         <
    1343              :             __is_cpp17_forward_iterator<_ForwardIterator>::value,
    1344              :             iterator
    1345              :         >
    1346              :         insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last);
    1347              : #ifndef _LIBCPP_CXX03_LANG
    1348              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1349              :     iterator insert(const_iterator __pos, initializer_list<value_type> __il)
    1350              :                     {return insert(__pos, __il.begin(), __il.end());}
    1351              : #endif // _LIBCPP_CXX03_LANG
    1352              : 
    1353              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& erase(size_type __pos = 0, size_type __n = npos);
    1354              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1355              :     iterator      erase(const_iterator __pos);
    1356              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1357              :     iterator      erase(const_iterator __first, const_iterator __last);
    1358              : 
    1359              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
    1360              :   replace(size_type __pos1, size_type __n1, const basic_string& __str) {
    1361              :     return replace(__pos1, __n1, __str.data(), __str.size());
    1362              :   }
    1363              : 
    1364              :     template <class _Tp>
    1365              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1366              :     __enable_if_t
    1367              :         <
    1368              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1369              :             basic_string&
    1370              :         >
    1371              :                   replace(size_type __pos1, size_type __n1, const _Tp& __t) { __self_view __sv = __t; return replace(__pos1, __n1, __sv.data(), __sv.size()); }
    1372              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1373              :     basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos);
    1374              :     template <class _Tp>
    1375              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1376              :     __enable_if_t
    1377              :         <
    1378              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value  && !__is_same_uncvref<_Tp, basic_string>::value,
    1379              :             basic_string&
    1380              :         >
    1381              :                   replace(size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2=npos);
    1382              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1383              :     basic_string& replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2);
    1384              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& replace(size_type __pos, size_type __n1, const value_type* __s);
    1385              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& replace(size_type __pos, size_type __n1, size_type __n2, value_type __c);
    1386              : 
    1387              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
    1388              :   replace(const_iterator __i1, const_iterator __i2, const basic_string& __str) {
    1389              :     return replace(
    1390              :         static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __str.data(), __str.size());
    1391              :   }
    1392              : 
    1393              :     template <class _Tp>
    1394              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1395              :     __enable_if_t
    1396              :         <
    1397              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1398              :             basic_string&
    1399              :         >
    1400              :                   replace(const_iterator __i1, const_iterator __i2, const _Tp& __t) { __self_view __sv = __t; return replace(__i1 - begin(), __i2 - __i1, __sv); }
    1401              : 
    1402              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
    1403              :   replace(const_iterator __i1, const_iterator __i2, const value_type* __s, size_type __n) {
    1404              :     return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s, __n);
    1405              :   }
    1406              : 
    1407              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
    1408              :   replace(const_iterator __i1, const_iterator __i2, const value_type* __s) {
    1409              :     return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s);
    1410              :   }
    1411              : 
    1412              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
    1413              :   replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c) {
    1414              :     return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __n, __c);
    1415              :   }
    1416              : 
    1417              :     template<class _InputIterator>
    1418              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1419              :     __enable_if_t
    1420              :         <
    1421              :             __is_cpp17_input_iterator<_InputIterator>::value,
    1422              :             basic_string&
    1423              :         >
    1424              :         replace(const_iterator __i1, const_iterator __i2, _InputIterator __j1, _InputIterator __j2);
    1425              : #ifndef _LIBCPP_CXX03_LANG
    1426              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1427              :     basic_string& replace(const_iterator __i1, const_iterator __i2, initializer_list<value_type> __il)
    1428              :         {return replace(__i1, __i2, __il.begin(), __il.end());}
    1429              : #endif // _LIBCPP_CXX03_LANG
    1430              : 
    1431              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type copy(value_type* __s, size_type __n, size_type __pos = 0) const;
    1432              : 
    1433              : #if _LIBCPP_STD_VER <= 20
    1434              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1435         2464 :     basic_string substr(size_type __pos = 0, size_type __n = npos) const {
    1436         2464 :       return basic_string(*this, __pos, __n);
    1437              :     }
    1438              : #else
    1439              :     _LIBCPP_HIDE_FROM_ABI constexpr
    1440              :     basic_string substr(size_type __pos = 0, size_type __n = npos) const& {
    1441              :       return basic_string(*this, __pos, __n);
    1442              :     }
    1443              : 
    1444              :     _LIBCPP_HIDE_FROM_ABI constexpr
    1445              :     basic_string substr(size_type __pos = 0, size_type __n = npos) && {
    1446              :       return basic_string(std::move(*this), __pos, __n);
    1447              :     }
    1448              : #endif
    1449              : 
    1450              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1451              :     void swap(basic_string& __str)
    1452              : #if _LIBCPP_STD_VER >= 14
    1453              :         _NOEXCEPT;
    1454              : #else
    1455              :         _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
    1456              :                     __is_nothrow_swappable<allocator_type>::value);
    1457              : #endif
    1458              : 
    1459              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1460          909 :     const value_type* c_str() const _NOEXCEPT {return data();}
    1461              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1462        66034 :     const value_type* data() const _NOEXCEPT  {return std::__to_address(__get_pointer());}
    1463              : #if _LIBCPP_STD_VER > 14 || defined(_LIBCPP_BUILDING_LIBRARY)
    1464              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1465              :     value_type* data()             _NOEXCEPT  {return std::__to_address(__get_pointer());}
    1466              : #endif
    1467              : 
    1468              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1469              :     allocator_type get_allocator() const _NOEXCEPT {return __alloc();}
    1470              : 
    1471              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1472              :     size_type find(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
    1473              : 
    1474              :     template <class _Tp>
    1475              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1476              :     __enable_if_t
    1477              :         <
    1478              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1479              :             size_type
    1480              :         >
    1481              :               find(const _Tp& __t, size_type __pos = 0) const _NOEXCEPT;
    1482              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1483              :     size_type find(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
    1484              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1485              :     size_type find(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
    1486              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type find(value_type __c, size_type __pos = 0) const _NOEXCEPT;
    1487              : 
    1488              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1489              :     size_type rfind(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
    1490              : 
    1491              :     template <class _Tp>
    1492              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1493              :     __enable_if_t
    1494              :         <
    1495              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1496              :             size_type
    1497              :         >
    1498              :               rfind(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT;
    1499              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1500              :     size_type rfind(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
    1501              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1502              :     size_type rfind(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
    1503              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type rfind(value_type __c, size_type __pos = npos) const _NOEXCEPT;
    1504              : 
    1505              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1506              :     size_type find_first_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
    1507              : 
    1508              :     template <class _Tp>
    1509              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1510              :     __enable_if_t
    1511              :         <
    1512              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1513              :             size_type
    1514              :         >
    1515              :               find_first_of(const _Tp& __t, size_type __pos = 0) const _NOEXCEPT;
    1516              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1517              :     size_type find_first_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
    1518              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1519              :     size_type find_first_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
    1520              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1521              :     size_type find_first_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
    1522              : 
    1523              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1524              :     size_type find_last_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
    1525              : 
    1526              :     template <class _Tp>
    1527              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1528              :     __enable_if_t
    1529              :         <
    1530              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1531              :             size_type
    1532              :         >
    1533              :               find_last_of(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT;
    1534              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1535              :     size_type find_last_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
    1536              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1537              :     size_type find_last_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
    1538              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1539              :     size_type find_last_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
    1540              : 
    1541              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1542              :     size_type find_first_not_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
    1543              : 
    1544              :     template <class _Tp>
    1545              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1546              :     __enable_if_t
    1547              :         <
    1548              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1549              :             size_type
    1550              :         >
    1551              :               find_first_not_of(const _Tp &__t, size_type __pos = 0) const _NOEXCEPT;
    1552              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1553              :     size_type find_first_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
    1554              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1555              :     size_type find_first_not_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
    1556              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1557              :     size_type find_first_not_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
    1558              : 
    1559              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1560              :     size_type find_last_not_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
    1561              : 
    1562              :     template <class _Tp>
    1563              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1564              :     __enable_if_t
    1565              :         <
    1566              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1567              :             size_type
    1568              :         >
    1569              :               find_last_not_of(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT;
    1570              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1571              :     size_type find_last_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
    1572              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1573              :     size_type find_last_not_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
    1574              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1575              :     size_type find_last_not_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
    1576              : 
    1577              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1578              :     int compare(const basic_string& __str) const _NOEXCEPT;
    1579              : 
    1580              :     template <class _Tp>
    1581              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1582              :     __enable_if_t
    1583              :         <
    1584              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1585              :             int
    1586              :         >
    1587              :         compare(const _Tp &__t) const _NOEXCEPT;
    1588              : 
    1589              :     template <class _Tp>
    1590              :     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
    1591              :     __enable_if_t
    1592              :         <
    1593              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    1594              :             int
    1595              :         >
    1596              :          compare(size_type __pos1, size_type __n1, const _Tp& __t) const;
    1597              : 
    1598              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1599              :     int compare(size_type __pos1, size_type __n1, const basic_string& __str) const;
    1600              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1601              :     int compare(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2,
    1602              :                 size_type __n2 = npos) const;
    1603              : 
    1604              :     template <class _Tp>
    1605              :     inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1606              :         __enable_if_t
    1607              :         <
    1608              :             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value  && !__is_same_uncvref<_Tp, basic_string>::value,
    1609              :             int
    1610              :         >
    1611              :         compare(size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2=npos) const;
    1612              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 int compare(const value_type* __s) const _NOEXCEPT;
    1613              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 int compare(size_type __pos1, size_type __n1, const value_type* __s) const;
    1614              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1615              :     int compare(size_type __pos1, size_type __n1, const value_type* __s, size_type __n2) const;
    1616              : 
    1617              : #if _LIBCPP_STD_VER > 17
    1618              :     constexpr _LIBCPP_HIDE_FROM_ABI
    1619              :     bool starts_with(__self_view __sv) const noexcept
    1620              :     { return __self_view(data(), size()).starts_with(__sv); }
    1621              : 
    1622              :     constexpr _LIBCPP_HIDE_FROM_ABI
    1623              :     bool starts_with(value_type __c) const noexcept
    1624              :     { return !empty() && _Traits::eq(front(), __c); }
    1625              : 
    1626              :     constexpr _LIBCPP_HIDE_FROM_ABI
    1627              :     bool starts_with(const value_type* __s) const noexcept
    1628              :     { return starts_with(__self_view(__s)); }
    1629              : 
    1630              :     constexpr _LIBCPP_HIDE_FROM_ABI
    1631              :     bool ends_with(__self_view __sv) const noexcept
    1632              :     { return __self_view(data(), size()).ends_with( __sv); }
    1633              : 
    1634              :     constexpr _LIBCPP_HIDE_FROM_ABI
    1635              :     bool ends_with(value_type __c) const noexcept
    1636              :     { return !empty() && _Traits::eq(back(), __c); }
    1637              : 
    1638              :     constexpr _LIBCPP_HIDE_FROM_ABI
    1639              :     bool ends_with(const value_type* __s) const noexcept
    1640              :     { return ends_with(__self_view(__s)); }
    1641              : #endif
    1642              : 
    1643              : #if _LIBCPP_STD_VER > 20
    1644              :     constexpr _LIBCPP_HIDE_FROM_ABI
    1645              :     bool contains(__self_view __sv) const noexcept
    1646              :     { return __self_view(data(), size()).contains(__sv); }
    1647              : 
    1648              :     constexpr _LIBCPP_HIDE_FROM_ABI
    1649              :     bool contains(value_type __c) const noexcept
    1650              :     { return __self_view(data(), size()).contains(__c); }
    1651              : 
    1652              :     constexpr _LIBCPP_HIDE_FROM_ABI
    1653              :     bool contains(const value_type* __s) const
    1654              :     { return __self_view(data(), size()).contains(__s); }
    1655              : #endif
    1656              : 
    1657              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __invariants() const;
    1658              : 
    1659              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __clear_and_shrink() _NOEXCEPT;
    1660              : 
    1661              : #ifdef _LIBCPP_ENABLE_DEBUG_MODE
    1662              : 
    1663              :     bool __dereferenceable(const const_iterator* __i) const;
    1664              :     bool __decrementable(const const_iterator* __i) const;
    1665              :     bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
    1666              :     bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
    1667              : 
    1668              : #endif // _LIBCPP_ENABLE_DEBUG_MODE
    1669              : 
    1670              : private:
    1671              :     template<class _Alloc>
    1672              :     inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1673              :     bool friend operator==(const basic_string<char, char_traits<char>, _Alloc>& __lhs,
    1674              :                            const basic_string<char, char_traits<char>, _Alloc>& __rhs) _NOEXCEPT;
    1675              : 
    1676              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __shrink_or_extend(size_type __target_capacity);
    1677              : 
    1678              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1679       214827 :     bool __is_long() const _NOEXCEPT {
    1680       214827 :         if (__libcpp_is_constant_evaluated())
    1681            0 :             return true;
    1682       214827 :         return __r_.first().__s.__is_long_;
    1683       214827 :     }
    1684              : 
    1685            0 :     static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __begin_lifetime(pointer __begin, size_type __n) {
    1686              : #if _LIBCPP_STD_VER > 17
    1687              :         if (__libcpp_is_constant_evaluated()) {
    1688              :             for (size_type __i = 0; __i != __n; ++__i)
    1689              :                 std::construct_at(std::addressof(__begin[__i]));
    1690              :         }
    1691              : #else
    1692              :         (void)__begin;
    1693              :         (void)__n;
    1694              : #endif // _LIBCPP_STD_VER > 17
    1695            0 :     }
    1696              : 
    1697         8301 :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __default_init() {
    1698         8301 :         __r_.first() = __rep();
    1699         8301 :         if (__libcpp_is_constant_evaluated()) {
    1700            0 :             size_type __sz = __recommend(0) + 1;
    1701            0 :             pointer __ptr = __alloc_traits::allocate(__alloc(), __sz);
    1702            0 :             __begin_lifetime(__ptr, __sz);
    1703            0 :             __set_long_pointer(__ptr);
    1704            0 :             __set_long_cap(__sz);
    1705            0 :             __set_long_size(0);
    1706            0 :         }
    1707         8301 :     }
    1708              : 
    1709              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __deallocate_constexpr() {
    1710              :         if (__libcpp_is_constant_evaluated() && __get_pointer() != nullptr)
    1711              :             __alloc_traits::deallocate(__alloc(), __get_pointer(), __get_long_cap());
    1712              :     }
    1713              : 
    1714              :     _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI static bool __fits_in_sso(size_type __sz) {
    1715              :         // SSO is disabled during constant evaluation because `__is_long` isn't constexpr friendly
    1716              :         return !__libcpp_is_constant_evaluated() && (__sz < __min_cap);
    1717              :     }
    1718              : 
    1719              :     template <class _ForwardIterator>
    1720              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
    1721              :     iterator __insert_from_safe_copy(size_type __n, size_type __ip, _ForwardIterator __first, _ForwardIterator __last) {
    1722              :         size_type __sz = size();
    1723              :         size_type __cap = capacity();
    1724              :         value_type* __p;
    1725              :         if (__cap - __sz >= __n)
    1726              :         {
    1727              :             __p = std::__to_address(__get_pointer());
    1728              :             size_type __n_move = __sz - __ip;
    1729              :             if (__n_move != 0)
    1730              :                 traits_type::move(__p + __ip + __n, __p + __ip, __n_move);
    1731              :         }
    1732              :         else
    1733              :         {
    1734              :             __grow_by(__cap, __sz + __n - __cap, __sz, __ip, 0, __n);
    1735              :             __p = std::__to_address(__get_long_pointer());
    1736              :         }
    1737              :         __sz += __n;
    1738              :         __set_size(__sz);
    1739              :         traits_type::assign(__p[__sz], value_type());
    1740              :         for (__p += __ip; __first != __last; ++__p, ++__first)
    1741              :             traits_type::assign(*__p, *__first);
    1742              : 
    1743              :         return begin() + __ip;
    1744              :     }
    1745              : 
    1746            0 :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 allocator_type& __alloc() _NOEXCEPT { return __r_.second(); }
    1747        36845 :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const allocator_type& __alloc() const _NOEXCEPT { return __r_.second(); }
    1748              : 
    1749              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1750          749 :     void __set_short_size(size_type __s) _NOEXCEPT {
    1751          749 :         _LIBCPP_ASSERT(__s < __min_cap, "__s should never be greater than or equal to the short string capacity");
    1752          749 :         __r_.first().__s.__size_ = __s;
    1753          749 :         __r_.first().__s.__is_long_ = false;
    1754          749 :     }
    1755              : 
    1756              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1757        94466 :     size_type __get_short_size() const _NOEXCEPT {
    1758              :         _LIBCPP_ASSERT(!__r_.first().__s.__is_long_, "String has to be short when trying to get the short size");
    1759        94466 :         return __r_.first().__s.__size_;
    1760              :     }
    1761              : 
    1762              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1763            0 :     void __set_long_size(size_type __s) _NOEXCEPT
    1764            0 :         {__r_.first().__l.__size_ = __s;}
    1765              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1766        31316 :     size_type __get_long_size() const _NOEXCEPT
    1767        31316 :         {return __r_.first().__l.__size_;}
    1768              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1769              :     void __set_size(size_type __s) _NOEXCEPT
    1770              :         {if (__is_long()) __set_long_size(__s); else __set_short_size(__s);}
    1771              : 
    1772              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1773            0 :     void __set_long_cap(size_type __s) _NOEXCEPT {
    1774            0 :         __r_.first().__l.__cap_ = __s / __endian_factor;
    1775            0 :         __r_.first().__l.__is_long_ = true;
    1776            0 :     }
    1777              : 
    1778              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1779              :     size_type __get_long_cap() const _NOEXCEPT {
    1780              :         return __r_.first().__l.__cap_ * __endian_factor;
    1781              :     }
    1782              : 
    1783              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1784            0 :     void __set_long_pointer(pointer __p) _NOEXCEPT
    1785            0 :         {__r_.first().__l.__data_ = __p;}
    1786              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1787            0 :     pointer __get_long_pointer() _NOEXCEPT
    1788            0 :         {return __r_.first().__l.__data_;}
    1789              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1790         9052 :     const_pointer __get_long_pointer() const _NOEXCEPT
    1791         9052 :         {return __r_.first().__l.__data_;}
    1792              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1793        23011 :     pointer __get_short_pointer() _NOEXCEPT
    1794        23011 :         {return pointer_traits<pointer>::pointer_to(__r_.first().__s.__data_[0]);}
    1795              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1796        56982 :     const_pointer __get_short_pointer() const _NOEXCEPT
    1797        56982 :         {return pointer_traits<const_pointer>::pointer_to(__r_.first().__s.__data_[0]);}
    1798              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1799        22262 :     pointer __get_pointer() _NOEXCEPT
    1800        22262 :         {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
    1801              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1802        66034 :     const_pointer __get_pointer() const _NOEXCEPT
    1803        66034 :         {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
    1804              : 
    1805              :     template <size_type __a> static
    1806              :         _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1807            0 :         size_type __align_it(size_type __s) _NOEXCEPT
    1808            0 :             {return (__s + (__a-1)) & ~(__a-1);}
    1809              :     enum {__alignment = 16};
    1810              :     static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1811            0 :     size_type __recommend(size_type __s) _NOEXCEPT
    1812              :     {
    1813            0 :         if (__s < __min_cap) {
    1814            0 :             if (__libcpp_is_constant_evaluated())
    1815            0 :                 return static_cast<size_type>(__min_cap);
    1816              :             else
    1817            0 :                 return static_cast<size_type>(__min_cap) - 1;
    1818              :         }
    1819            0 :         size_type __guess = __align_it<sizeof(value_type) < __alignment ?
    1820            0 :                      __alignment/sizeof(value_type) : 1 > (__s+1) - 1;
    1821            0 :         if (__guess == __min_cap) ++__guess;
    1822            0 :         return __guess;
    1823            0 :     }
    1824              : 
    1825              :     inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    1826              :     void __init(const value_type* __s, size_type __sz, size_type __reserve);
    1827              :     inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    1828              :     void __init(const value_type* __s, size_type __sz);
    1829              :     inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    1830              :     void __init(size_type __n, value_type __c);
    1831              : 
    1832              :     // Slow path for the (inlined) copy constructor for 'long' strings.
    1833              :     // Always externally instantiated and not inlined.
    1834              :     // Requires that __s is zero terminated.
    1835              :     // The main reason for this function to exist is because for unstable, we
    1836              :     // want to allow inlining of the copy constructor. However, we don't want
    1837              :     // to call the __init() functions as those are marked as inline which may
    1838              :     // result in over-aggressive inlining by the compiler, where our aim is
    1839              :     // to only inline the fast path code directly in the ctor.
    1840              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 void __init_copy_ctor_external(const value_type* __s, size_type __sz);
    1841              : 
    1842              :     template <class _InputIterator>
    1843              :     inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    1844              :     __enable_if_t
    1845              :     <
    1846              :         __is_exactly_cpp17_input_iterator<_InputIterator>::value
    1847              :     >
    1848              :     __init(_InputIterator __first, _InputIterator __last);
    1849              : 
    1850              :     template <class _ForwardIterator>
    1851              :     inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    1852              :     __enable_if_t
    1853              :     <
    1854              :         __is_cpp17_forward_iterator<_ForwardIterator>::value
    1855              :     >
    1856              :     __init(_ForwardIterator __first, _ForwardIterator __last);
    1857              : 
    1858              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1859              :     void __grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
    1860              :                    size_type __n_copy,  size_type __n_del,     size_type __n_add = 0);
    1861              :     _LIBCPP_CONSTEXPR_SINCE_CXX20
    1862              :     void __grow_by_and_replace(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
    1863              :                                size_type __n_copy,  size_type __n_del,
    1864              :                                size_type __n_add, const value_type* __p_new_stuff);
    1865              : 
    1866              :     // __assign_no_alias is invoked for assignment operations where we
    1867              :     // have proof that the input does not alias the current instance.
    1868              :     // For example, operator=(basic_string) performs a 'self' check.
    1869              :     template <bool __is_short>
    1870              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& __assign_no_alias(const value_type* __s, size_type __n);
    1871              : 
    1872              :   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __erase_to_end(size_type __pos) {
    1873              :     __null_terminate_at(std::__to_address(__get_pointer()), __pos);
    1874              :   }
    1875              : 
    1876              :     // __erase_external_with_move is invoked for erase() invocations where
    1877              :     // `n ~= npos`, likely requiring memory moves on the string data.
    1878              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 void __erase_external_with_move(size_type __pos, size_type __n);
    1879              : 
    1880              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1881              :     void __copy_assign_alloc(const basic_string& __str)
    1882              :         {__copy_assign_alloc(__str, integral_constant<bool,
    1883              :                       __alloc_traits::propagate_on_container_copy_assignment::value>());}
    1884              : 
    1885              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1886              :     void __copy_assign_alloc(const basic_string& __str, true_type)
    1887              :         {
    1888              :             if (__alloc() == __str.__alloc())
    1889              :                 __alloc() = __str.__alloc();
    1890              :             else
    1891              :             {
    1892              :                 if (!__str.__is_long())
    1893              :                 {
    1894              :                     __clear_and_shrink();
    1895              :                     __alloc() = __str.__alloc();
    1896              :                 }
    1897              :                 else
    1898              :                 {
    1899              :                     allocator_type __a = __str.__alloc();
    1900              :                     auto __allocation = std::__allocate_at_least(__a, __str.__get_long_cap());
    1901              :                     __begin_lifetime(__allocation.ptr, __allocation.count);
    1902              :                     __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
    1903              :                     __alloc() = std::move(__a);
    1904              :                     __set_long_pointer(__allocation.ptr);
    1905              :                     __set_long_cap(__allocation.count);
    1906              :                     __set_long_size(__str.size());
    1907              :                 }
    1908              :             }
    1909              :         }
    1910              : 
    1911              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1912              :     void __copy_assign_alloc(const basic_string&, false_type) _NOEXCEPT
    1913              :         {}
    1914              : 
    1915              : #ifndef _LIBCPP_CXX03_LANG
    1916              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1917              :     void __move_assign(basic_string& __str, false_type)
    1918              :         _NOEXCEPT_(__alloc_traits::is_always_equal::value);
    1919              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1920              :     void __move_assign(basic_string& __str, true_type)
    1921              : #if _LIBCPP_STD_VER > 14
    1922              :         _NOEXCEPT;
    1923              : #else
    1924              :         _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
    1925              : #endif
    1926              : #endif
    1927              : 
    1928              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1929              :     void
    1930              :     __move_assign_alloc(basic_string& __str)
    1931              :         _NOEXCEPT_(
    1932              :             !__alloc_traits::propagate_on_container_move_assignment::value ||
    1933              :             is_nothrow_move_assignable<allocator_type>::value)
    1934              :     {__move_assign_alloc(__str, integral_constant<bool,
    1935              :                       __alloc_traits::propagate_on_container_move_assignment::value>());}
    1936              : 
    1937              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1938              :     void __move_assign_alloc(basic_string& __c, true_type)
    1939              :         _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
    1940              :         {
    1941              :             __alloc() = std::move(__c.__alloc());
    1942              :         }
    1943              : 
    1944              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1945              :     void __move_assign_alloc(basic_string&, false_type)
    1946              :         _NOEXCEPT
    1947              :         {}
    1948              : 
    1949              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& __assign_external(const value_type* __s);
    1950              :     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& __assign_external(const value_type* __s, size_type __n);
    1951              : 
    1952              :     // Assigns the value in __s, guaranteed to be __n < __min_cap in length.
    1953              :     inline basic_string& __assign_short(const value_type* __s, size_type __n) {
    1954              :       pointer __p = __is_long()
    1955              :                         ? (__set_long_size(__n), __get_long_pointer())
    1956              :                         : (__set_short_size(__n), __get_short_pointer());
    1957              :       traits_type::move(std::__to_address(__p), __s, __n);
    1958              :       traits_type::assign(__p[__n], value_type());
    1959              :       return *this;
    1960              :     }
    1961              : 
    1962              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1963              :     basic_string& __null_terminate_at(value_type* __p, size_type __newsz) {
    1964              :       __set_size(__newsz);
    1965              :       __invalidate_iterators_past(__newsz);
    1966              :       traits_type::assign(__p[__newsz], value_type());
    1967              :       return *this;
    1968              :     }
    1969              : 
    1970              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __invalidate_iterators_past(size_type);
    1971              : 
    1972              :     template<class _Tp>
    1973              :     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    1974              :     bool __addr_in_range(_Tp&& __t) const {
    1975              :         // assume that the ranges overlap, because we can't check during constant evaluation
    1976              :         if (__libcpp_is_constant_evaluated())
    1977              :           return true;
    1978              :         const volatile void *__p = std::addressof(__t);
    1979              :         return data() <= __p && __p <= data() + size();
    1980              :     }
    1981              : 
    1982              :     _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI
    1983              :     void __throw_length_error() const {
    1984              :         std::__throw_length_error("basic_string");
    1985              :     }
    1986              : 
    1987              :     _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI
    1988              :     void __throw_out_of_range() const {
    1989              :         std::__throw_out_of_range("basic_string");
    1990              :     }
    1991              : 
    1992              :     friend _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string operator+<>(const basic_string&, const basic_string&);
    1993              :     friend _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string operator+<>(const value_type*, const basic_string&);
    1994              :     friend _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string operator+<>(value_type, const basic_string&);
    1995              :     friend _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string operator+<>(const basic_string&, const value_type*);
    1996              :     friend _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string operator+<>(const basic_string&, value_type);
    1997              : };
    1998              : 
    1999              : // These declarations must appear before any functions are implicitly used
    2000              : // so that they have the correct visibility specifier.
    2001              : #define _LIBCPP_DECLARE(...) extern template __VA_ARGS__;
    2002              : #ifdef _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
    2003              :     _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_DECLARE, char)
    2004              : #   ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
    2005              :         _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_DECLARE, wchar_t)
    2006              : #   endif
    2007              : #else
    2008              :     _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_LIBCPP_DECLARE, char)
    2009              : #   ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
    2010              :         _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_LIBCPP_DECLARE, wchar_t)
    2011              : #   endif
    2012              : #endif
    2013              : #undef _LIBCPP_DECLARE
    2014              : 
    2015              : 
    2016              : #if _LIBCPP_STD_VER >= 17
    2017              : template<class _InputIterator,
    2018              :          class _CharT = __iter_value_type<_InputIterator>,
    2019              :          class _Allocator = allocator<_CharT>,
    2020              :          class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
    2021              :          class = enable_if_t<__is_allocator<_Allocator>::value>
    2022              :          >
    2023              : basic_string(_InputIterator, _InputIterator, _Allocator = _Allocator())
    2024              :   -> basic_string<_CharT, char_traits<_CharT>, _Allocator>;
    2025              : 
    2026              : template<class _CharT,
    2027              :          class _Traits,
    2028              :          class _Allocator = allocator<_CharT>,
    2029              :          class = enable_if_t<__is_allocator<_Allocator>::value>
    2030              :          >
    2031              : explicit basic_string(basic_string_view<_CharT, _Traits>, const _Allocator& = _Allocator())
    2032              :   -> basic_string<_CharT, _Traits, _Allocator>;
    2033              : 
    2034              : template<class _CharT,
    2035              :          class _Traits,
    2036              :          class _Allocator = allocator<_CharT>,
    2037              :          class = enable_if_t<__is_allocator<_Allocator>::value>,
    2038              :          class _Sz = typename allocator_traits<_Allocator>::size_type
    2039              :          >
    2040              : basic_string(basic_string_view<_CharT, _Traits>, _Sz, _Sz, const _Allocator& = _Allocator())
    2041              :   -> basic_string<_CharT, _Traits, _Allocator>;
    2042              : #endif
    2043              : 
    2044              : template <class _CharT, class _Traits, class _Allocator>
    2045              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    2046              : void
    2047              : basic_string<_CharT, _Traits, _Allocator>::__invalidate_iterators_past(size_type __pos)
    2048              : {
    2049              : #ifdef _LIBCPP_ENABLE_DEBUG_MODE
    2050              :     if (!__libcpp_is_constant_evaluated()) {
    2051              :         __c_node* __c = __get_db()->__find_c_and_lock(this);
    2052              :         if (__c)
    2053              :         {
    2054              :             const_pointer __new_last = __get_pointer() + __pos;
    2055              :             for (__i_node** __p = __c->end_; __p != __c->beg_; )
    2056              :             {
    2057              :                 --__p;
    2058              :                 const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
    2059              :                 if (__i->base() > __new_last)
    2060              :                 {
    2061              :                     (*__p)->__c_ = nullptr;
    2062              :                     if (--__c->end_ != __p)
    2063              :                         std::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
    2064              :                 }
    2065              :             }
    2066              :             __get_db()->unlock();
    2067              :         }
    2068              :     }
    2069              : #else
    2070              :     (void)__pos;
    2071              : #endif // _LIBCPP_ENABLE_DEBUG_MODE
    2072              : }
    2073              : 
    2074              : template <class _CharT, class _Traits, class _Allocator>
    2075              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2076              : void basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s,
    2077              :                                                        size_type __sz,
    2078              :                                                        size_type __reserve)
    2079              : {
    2080              :     if (__libcpp_is_constant_evaluated())
    2081              :         __r_.first() = __rep();
    2082              :     if (__reserve > max_size())
    2083              :         __throw_length_error();
    2084              :     pointer __p;
    2085              :     if (__fits_in_sso(__reserve))
    2086              :     {
    2087              :         __set_short_size(__sz);
    2088              :         __p = __get_short_pointer();
    2089              :     }
    2090              :     else
    2091              :     {
    2092              :         auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__reserve) + 1);
    2093              :         __p = __allocation.ptr;
    2094              :         __begin_lifetime(__p, __allocation.count);
    2095              :         __set_long_pointer(__p);
    2096              :         __set_long_cap(__allocation.count);
    2097              :         __set_long_size(__sz);
    2098              :     }
    2099              :     traits_type::copy(std::__to_address(__p), __s, __sz);
    2100              :     traits_type::assign(__p[__sz], value_type());
    2101              : }
    2102              : 
    2103              : template <class _CharT, class _Traits, class _Allocator>
    2104              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2105              : void
    2106              : basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz)
    2107              : {
    2108              :     if (__libcpp_is_constant_evaluated())
    2109              :         __r_.first() = __rep();
    2110              :     if (__sz > max_size())
    2111              :         __throw_length_error();
    2112              :     pointer __p;
    2113              :     if (__fits_in_sso(__sz))
    2114              :     {
    2115              :         __set_short_size(__sz);
    2116              :         __p = __get_short_pointer();
    2117              :     }
    2118              :     else
    2119              :     {
    2120              :         auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__sz) + 1);
    2121              :         __p = __allocation.ptr;
    2122              :         __begin_lifetime(__p, __allocation.count);
    2123              :         __set_long_pointer(__p);
    2124              :         __set_long_cap(__allocation.count);
    2125              :         __set_long_size(__sz);
    2126              :     }
    2127              :     traits_type::copy(std::__to_address(__p), __s, __sz);
    2128              :     traits_type::assign(__p[__sz], value_type());
    2129              : }
    2130              : 
    2131              : template <class _CharT, class _Traits, class _Allocator>
    2132              : template <class>
    2133              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2134              : basic_string<_CharT, _Traits, _Allocator>::basic_string(const _CharT* __s, const _Allocator& __a)
    2135              :     : __r_(__default_init_tag(), __a)
    2136              : {
    2137              :     _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*, allocator) detected nullptr");
    2138              :     __init(__s, traits_type::length(__s));
    2139              :     std::__debug_db_insert_c(this);
    2140              : }
    2141              : 
    2142              : template <class _CharT, class _Traits, class _Allocator>
    2143              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2144              : basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str)
    2145              :     : __r_(__default_init_tag(), __alloc_traits::select_on_container_copy_construction(__str.__alloc()))
    2146              : {
    2147              :     if (!__str.__is_long())
    2148              :         __r_.first() = __str.__r_.first();
    2149              :     else
    2150              :         __init_copy_ctor_external(std::__to_address(__str.__get_long_pointer()),
    2151              :                                   __str.__get_long_size());
    2152              :     std::__debug_db_insert_c(this);
    2153              : }
    2154              : 
    2155              : template <class _CharT, class _Traits, class _Allocator>
    2156              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2157              : basic_string<_CharT, _Traits, _Allocator>::basic_string(
    2158              :     const basic_string& __str, const allocator_type& __a)
    2159              :     : __r_(__default_init_tag(), __a)
    2160              : {
    2161              :     if (!__str.__is_long())
    2162              :         __r_.first() = __str.__r_.first();
    2163              :     else
    2164              :         __init_copy_ctor_external(std::__to_address(__str.__get_long_pointer()),
    2165              :                                   __str.__get_long_size());
    2166              :     std::__debug_db_insert_c(this);
    2167              : }
    2168              : 
    2169              : template <class _CharT, class _Traits, class _Allocator>
    2170              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2171              : void basic_string<_CharT, _Traits, _Allocator>::__init_copy_ctor_external(
    2172              :     const value_type* __s, size_type __sz) {
    2173              :   if (__libcpp_is_constant_evaluated())
    2174              :     __r_.first() = __rep();
    2175              : 
    2176              :   pointer __p;
    2177              :   if (__fits_in_sso(__sz)) {
    2178              :     __p = __get_short_pointer();
    2179              :     __set_short_size(__sz);
    2180              :   } else {
    2181              :     if (__sz > max_size())
    2182              :       __throw_length_error();
    2183              :     auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__sz) + 1);
    2184              :     __p = __allocation.ptr;
    2185              :     __begin_lifetime(__p, __allocation.count);
    2186              :     __set_long_pointer(__p);
    2187              :     __set_long_cap(__allocation.count);
    2188              :     __set_long_size(__sz);
    2189              :   }
    2190              :   traits_type::copy(std::__to_address(__p), __s, __sz + 1);
    2191              : }
    2192              : 
    2193              : template <class _CharT, class _Traits, class _Allocator>
    2194              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2195              : void
    2196              : basic_string<_CharT, _Traits, _Allocator>::__init(size_type __n, value_type __c)
    2197              : {
    2198              :     if (__libcpp_is_constant_evaluated())
    2199              :         __r_.first() = __rep();
    2200              : 
    2201              :     if (__n > max_size())
    2202              :         __throw_length_error();
    2203              :     pointer __p;
    2204              :     if (__fits_in_sso(__n))
    2205              :     {
    2206              :         __set_short_size(__n);
    2207              :         __p = __get_short_pointer();
    2208              :     }
    2209              :     else
    2210              :     {
    2211              :         auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__n) + 1);
    2212              :         __p = __allocation.ptr;
    2213              :         __begin_lifetime(__p, __allocation.count);
    2214              :         __set_long_pointer(__p);
    2215              :         __set_long_cap(__allocation.count);
    2216              :         __set_long_size(__n);
    2217              :     }
    2218              :     traits_type::assign(std::__to_address(__p), __n, __c);
    2219              :     traits_type::assign(__p[__n], value_type());
    2220              : }
    2221              : 
    2222              : template <class _CharT, class _Traits, class _Allocator>
    2223              : template <class>
    2224              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2225              : basic_string<_CharT, _Traits, _Allocator>::basic_string(size_type __n, _CharT __c, const _Allocator& __a)
    2226              :     : __r_(__default_init_tag(), __a)
    2227              : {
    2228              :     __init(__n, __c);
    2229              :     std::__debug_db_insert_c(this);
    2230              : }
    2231              : 
    2232              : template <class _CharT, class _Traits, class _Allocator>
    2233              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2234              : basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str,
    2235              :                                                         size_type __pos, size_type __n,
    2236              :                                                         const _Allocator& __a)
    2237              :     : __r_(__default_init_tag(), __a)
    2238              : {
    2239              :     size_type __str_sz = __str.size();
    2240              :     if (__pos > __str_sz)
    2241              :         __throw_out_of_range();
    2242              :     __init(__str.data() + __pos, std::min(__n, __str_sz - __pos));
    2243              :     std::__debug_db_insert_c(this);
    2244              : }
    2245              : 
    2246              : template <class _CharT, class _Traits, class _Allocator>
    2247              : template <class _Tp, class>
    2248              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2249              : basic_string<_CharT, _Traits, _Allocator>::basic_string(
    2250              :              const _Tp& __t, size_type __pos, size_type __n, const allocator_type& __a)
    2251              :     : __r_(__default_init_tag(), __a)
    2252              : {
    2253              :     __self_view __sv0 = __t;
    2254              :     __self_view __sv = __sv0.substr(__pos, __n);
    2255              :     __init(__sv.data(), __sv.size());
    2256              :     std::__debug_db_insert_c(this);
    2257              : }
    2258              : 
    2259              : template <class _CharT, class _Traits, class _Allocator>
    2260              : template <class _Tp, class>
    2261              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2262              : basic_string<_CharT, _Traits, _Allocator>::basic_string(const _Tp & __t)
    2263              :      : __r_(__default_init_tag(), __default_init_tag())
    2264              : {
    2265              :     __self_view __sv = __t;
    2266              :     __init(__sv.data(), __sv.size());
    2267              :     std::__debug_db_insert_c(this);
    2268              : }
    2269              : 
    2270              : template <class _CharT, class _Traits, class _Allocator>
    2271              : template <class _Tp, class>
    2272              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2273              : basic_string<_CharT, _Traits, _Allocator>::basic_string(const _Tp & __t, const _Allocator& __a)
    2274              :     : __r_(__default_init_tag(), __a)
    2275              : {
    2276              :     __self_view __sv = __t;
    2277              :     __init(__sv.data(), __sv.size());
    2278              :     std::__debug_db_insert_c(this);
    2279              : }
    2280              : 
    2281              : template <class _CharT, class _Traits, class _Allocator>
    2282              : template <class _InputIterator>
    2283              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2284              : __enable_if_t
    2285              : <
    2286              :     __is_exactly_cpp17_input_iterator<_InputIterator>::value
    2287              : >
    2288              : basic_string<_CharT, _Traits, _Allocator>::__init(_InputIterator __first, _InputIterator __last)
    2289              : {
    2290              :     __default_init();
    2291              : #ifndef _LIBCPP_NO_EXCEPTIONS
    2292              :     try
    2293              :     {
    2294              : #endif // _LIBCPP_NO_EXCEPTIONS
    2295              :     for (; __first != __last; ++__first)
    2296              :         push_back(*__first);
    2297              : #ifndef _LIBCPP_NO_EXCEPTIONS
    2298              :     }
    2299              :     catch (...)
    2300              :     {
    2301              :         if (__is_long())
    2302              :             __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
    2303              :         throw;
    2304              :     }
    2305              : #endif // _LIBCPP_NO_EXCEPTIONS
    2306              : }
    2307              : 
    2308              : template <class _CharT, class _Traits, class _Allocator>
    2309              : template <class _ForwardIterator>
    2310              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2311              : __enable_if_t
    2312              : <
    2313              :     __is_cpp17_forward_iterator<_ForwardIterator>::value
    2314              : >
    2315              : basic_string<_CharT, _Traits, _Allocator>::__init(_ForwardIterator __first, _ForwardIterator __last)
    2316              : {
    2317              :     if (__libcpp_is_constant_evaluated())
    2318              :         __r_.first() = __rep();
    2319              :     size_type __sz = static_cast<size_type>(std::distance(__first, __last));
    2320              :     if (__sz > max_size())
    2321              :         __throw_length_error();
    2322              :     pointer __p;
    2323              :     if (__fits_in_sso(__sz))
    2324              :     {
    2325              :         __set_short_size(__sz);
    2326              :         __p = __get_short_pointer();
    2327              :     }
    2328              :     else
    2329              :     {
    2330              :         auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__sz) + 1);
    2331              :         __p = __allocation.ptr;
    2332              :         __begin_lifetime(__p, __allocation.count);
    2333              :         __set_long_pointer(__p);
    2334              :         __set_long_cap(__allocation.count);
    2335              :         __set_long_size(__sz);
    2336              :     }
    2337              : 
    2338              : #ifndef _LIBCPP_NO_EXCEPTIONS
    2339              :     try
    2340              :     {
    2341              : #endif  // _LIBCPP_NO_EXCEPTIONS
    2342              :     for (; __first != __last; ++__first, (void) ++__p)
    2343              :         traits_type::assign(*__p, *__first);
    2344              :     traits_type::assign(*__p, value_type());
    2345              : #ifndef _LIBCPP_NO_EXCEPTIONS
    2346              :     }
    2347              :     catch (...)
    2348              :     {
    2349              :         if (__is_long())
    2350              :             __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
    2351              :         throw;
    2352              :     }
    2353              : #endif  // _LIBCPP_NO_EXCEPTIONS
    2354              : }
    2355              : 
    2356              : template <class _CharT, class _Traits, class _Allocator>
    2357              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2358              : basic_string<_CharT, _Traits, _Allocator>::~basic_string()
    2359              : {
    2360              :     std::__debug_db_erase_c(this);
    2361              :     if (__is_long())
    2362              :         __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
    2363              : }
    2364              : 
    2365              : template <class _CharT, class _Traits, class _Allocator>
    2366              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2367              : void
    2368              : basic_string<_CharT, _Traits, _Allocator>::__grow_by_and_replace
    2369              :     (size_type __old_cap, size_type __delta_cap, size_type __old_sz,
    2370              :      size_type __n_copy,  size_type __n_del,     size_type __n_add, const value_type* __p_new_stuff)
    2371              : {
    2372              :     size_type __ms = max_size();
    2373              :     if (__delta_cap > __ms - __old_cap - 1)
    2374              :         __throw_length_error();
    2375              :     pointer __old_p = __get_pointer();
    2376              :     size_type __cap = __old_cap < __ms / 2 - __alignment ?
    2377              :                           __recommend(std::max(__old_cap + __delta_cap, 2 * __old_cap)) :
    2378              :                           __ms - 1;
    2379              :     auto __allocation = std::__allocate_at_least(__alloc(), __cap + 1);
    2380              :     pointer __p = __allocation.ptr;
    2381              :     __begin_lifetime(__p, __allocation.count);
    2382              :     std::__debug_db_invalidate_all(this);
    2383              :     if (__n_copy != 0)
    2384              :         traits_type::copy(std::__to_address(__p),
    2385              :                           std::__to_address(__old_p), __n_copy);
    2386              :     if (__n_add != 0)
    2387              :         traits_type::copy(std::__to_address(__p) + __n_copy, __p_new_stuff, __n_add);
    2388              :     size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
    2389              :     if (__sec_cp_sz != 0)
    2390              :         traits_type::copy(std::__to_address(__p) + __n_copy + __n_add,
    2391              :                           std::__to_address(__old_p) + __n_copy + __n_del, __sec_cp_sz);
    2392              :     if (__old_cap+1 != __min_cap || __libcpp_is_constant_evaluated())
    2393              :         __alloc_traits::deallocate(__alloc(), __old_p, __old_cap+1);
    2394              :     __set_long_pointer(__p);
    2395              :     __set_long_cap(__allocation.count);
    2396              :     __old_sz = __n_copy + __n_add + __sec_cp_sz;
    2397              :     __set_long_size(__old_sz);
    2398              :     traits_type::assign(__p[__old_sz], value_type());
    2399              : }
    2400              : 
    2401              : template <class _CharT, class _Traits, class _Allocator>
    2402              : void
    2403              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2404              : basic_string<_CharT, _Traits, _Allocator>::__grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
    2405              :                                                      size_type __n_copy,  size_type __n_del,     size_type __n_add)
    2406              : {
    2407              :     size_type __ms = max_size();
    2408              :     if (__delta_cap > __ms - __old_cap)
    2409              :         __throw_length_error();
    2410              :     pointer __old_p = __get_pointer();
    2411              :     size_type __cap = __old_cap < __ms / 2 - __alignment ?
    2412              :                           __recommend(std::max(__old_cap + __delta_cap, 2 * __old_cap)) :
    2413              :                           __ms - 1;
    2414              :     auto __allocation = std::__allocate_at_least(__alloc(), __cap + 1);
    2415              :     pointer __p = __allocation.ptr;
    2416              :     __begin_lifetime(__p, __allocation.count);
    2417              :     std::__debug_db_invalidate_all(this);
    2418              :     if (__n_copy != 0)
    2419              :         traits_type::copy(std::__to_address(__p),
    2420              :                           std::__to_address(__old_p), __n_copy);
    2421              :     size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
    2422              :     if (__sec_cp_sz != 0)
    2423              :         traits_type::copy(std::__to_address(__p) + __n_copy + __n_add,
    2424              :                           std::__to_address(__old_p) + __n_copy + __n_del,
    2425              :                           __sec_cp_sz);
    2426              :     if (__libcpp_is_constant_evaluated() || __old_cap + 1 != __min_cap)
    2427              :         __alloc_traits::deallocate(__alloc(), __old_p, __old_cap + 1);
    2428              :     __set_long_pointer(__p);
    2429              :     __set_long_cap(__allocation.count);
    2430              : }
    2431              : 
    2432              : // assign
    2433              : 
    2434              : template <class _CharT, class _Traits, class _Allocator>
    2435              : template <bool __is_short>
    2436              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2437              : basic_string<_CharT, _Traits, _Allocator>&
    2438              : basic_string<_CharT, _Traits, _Allocator>::__assign_no_alias(
    2439              :     const value_type* __s, size_type __n) {
    2440              :   size_type __cap = __is_short ? static_cast<size_type>(__min_cap) : __get_long_cap();
    2441              :   if (__n < __cap) {
    2442              :     pointer __p = __is_short ? __get_short_pointer() : __get_long_pointer();
    2443              :     __is_short ? __set_short_size(__n) : __set_long_size(__n);
    2444              :     traits_type::copy(std::__to_address(__p), __s, __n);
    2445              :     traits_type::assign(__p[__n], value_type());
    2446              :     __invalidate_iterators_past(__n);
    2447              :   } else {
    2448              :     size_type __sz = __is_short ? __get_short_size() : __get_long_size();
    2449              :     __grow_by_and_replace(__cap - 1, __n - __cap + 1, __sz, 0, __sz, __n, __s);
    2450              :   }
    2451              :   return *this;
    2452              : }
    2453              : 
    2454              : template <class _CharT, class _Traits, class _Allocator>
    2455              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2456              : basic_string<_CharT, _Traits, _Allocator>&
    2457              : basic_string<_CharT, _Traits, _Allocator>::__assign_external(
    2458              :     const value_type* __s, size_type __n) {
    2459              :   size_type __cap = capacity();
    2460              :   if (__cap >= __n) {
    2461              :     value_type* __p = std::__to_address(__get_pointer());
    2462              :     traits_type::move(__p, __s, __n);
    2463              :     return __null_terminate_at(__p, __n);
    2464              :   } else {
    2465              :     size_type __sz = size();
    2466              :     __grow_by_and_replace(__cap, __n - __cap, __sz, 0, __sz, __n, __s);
    2467              :     return *this;
    2468              :   }
    2469              : }
    2470              : 
    2471              : template <class _CharT, class _Traits, class _Allocator>
    2472              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2473              : basic_string<_CharT, _Traits, _Allocator>&
    2474              : basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s, size_type __n)
    2475              : {
    2476              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::assign received nullptr");
    2477              :     return (__builtin_constant_p(__n) && __fits_in_sso(__n))
    2478              :                ? __assign_short(__s, __n)
    2479              :                : __assign_external(__s, __n);
    2480              : }
    2481              : 
    2482              : template <class _CharT, class _Traits, class _Allocator>
    2483              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2484              : basic_string<_CharT, _Traits, _Allocator>&
    2485              : basic_string<_CharT, _Traits, _Allocator>::assign(size_type __n, value_type __c)
    2486              : {
    2487              :     size_type __cap = capacity();
    2488              :     if (__cap < __n)
    2489              :     {
    2490              :         size_type __sz = size();
    2491              :         __grow_by(__cap, __n - __cap, __sz, 0, __sz);
    2492              :     }
    2493              :     value_type* __p = std::__to_address(__get_pointer());
    2494              :     traits_type::assign(__p, __n, __c);
    2495              :     return __null_terminate_at(__p, __n);
    2496              : }
    2497              : 
    2498              : template <class _CharT, class _Traits, class _Allocator>
    2499              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2500              : basic_string<_CharT, _Traits, _Allocator>&
    2501              : basic_string<_CharT, _Traits, _Allocator>::operator=(value_type __c)
    2502              : {
    2503              :     pointer __p;
    2504              :     if (__is_long())
    2505              :     {
    2506              :         __p = __get_long_pointer();
    2507              :         __set_long_size(1);
    2508              :     }
    2509              :     else
    2510              :     {
    2511              :         __p = __get_short_pointer();
    2512              :         __set_short_size(1);
    2513              :     }
    2514              :     traits_type::assign(*__p, __c);
    2515              :     traits_type::assign(*++__p, value_type());
    2516              :     __invalidate_iterators_past(1);
    2517              :     return *this;
    2518              : }
    2519              : 
    2520              : template <class _CharT, class _Traits, class _Allocator>
    2521              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2522              : basic_string<_CharT, _Traits, _Allocator>&
    2523              : basic_string<_CharT, _Traits, _Allocator>::operator=(const basic_string& __str)
    2524              : {
    2525              :   if (this != &__str) {
    2526              :     __copy_assign_alloc(__str);
    2527              :     if (!__is_long()) {
    2528              :       if (!__str.__is_long()) {
    2529              :         __r_.first() = __str.__r_.first();
    2530              :       } else {
    2531              :         return __assign_no_alias<true>(__str.data(), __str.size());
    2532              :       }
    2533              :     } else {
    2534              :       return __assign_no_alias<false>(__str.data(), __str.size());
    2535              :     }
    2536              :   }
    2537              :   return *this;
    2538              : }
    2539              : 
    2540              : #ifndef _LIBCPP_CXX03_LANG
    2541              : 
    2542              : template <class _CharT, class _Traits, class _Allocator>
    2543              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    2544              : void
    2545              : basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, false_type)
    2546              :     _NOEXCEPT_(__alloc_traits::is_always_equal::value)
    2547              : {
    2548              :     if (__alloc() != __str.__alloc())
    2549              :         assign(__str);
    2550              :     else
    2551              :         __move_assign(__str, true_type());
    2552              : }
    2553              : 
    2554              : template <class _CharT, class _Traits, class _Allocator>
    2555              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    2556              : void
    2557              : basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, true_type)
    2558              : #if _LIBCPP_STD_VER > 14
    2559              :     _NOEXCEPT
    2560              : #else
    2561              :     _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
    2562              : #endif
    2563              : {
    2564              :   if (__is_long()) {
    2565              :     __alloc_traits::deallocate(__alloc(), __get_long_pointer(),
    2566              :                                __get_long_cap());
    2567              : #if _LIBCPP_STD_VER <= 14
    2568              :     if (!is_nothrow_move_assignable<allocator_type>::value) {
    2569              :       __set_short_size(0);
    2570              :       traits_type::assign(__get_short_pointer()[0], value_type());
    2571              :     }
    2572              : #endif
    2573              :   }
    2574              :   __move_assign_alloc(__str);
    2575              :   __r_.first() = __str.__r_.first();
    2576              :   if (__libcpp_is_constant_evaluated()) {
    2577              :     __str.__default_init();
    2578              :   } else {
    2579              :     __str.__set_short_size(0);
    2580              :     traits_type::assign(__str.__get_short_pointer()[0], value_type());
    2581              :   }
    2582              : }
    2583              : 
    2584              : #endif
    2585              : 
    2586              : template <class _CharT, class _Traits, class _Allocator>
    2587              : template<class _InputIterator>
    2588              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2589              : __enable_if_t
    2590              : <
    2591              :      __is_exactly_cpp17_input_iterator<_InputIterator>::value,
    2592              :     basic_string<_CharT, _Traits, _Allocator>&
    2593              : >
    2594              : basic_string<_CharT, _Traits, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
    2595              : {
    2596              :     const basic_string __temp(__first, __last, __alloc());
    2597              :     assign(__temp.data(), __temp.size());
    2598              :     return *this;
    2599              : }
    2600              : 
    2601              : template <class _CharT, class _Traits, class _Allocator>
    2602              : template<class _ForwardIterator>
    2603              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2604              : __enable_if_t
    2605              : <
    2606              :     __is_cpp17_forward_iterator<_ForwardIterator>::value,
    2607              :     basic_string<_CharT, _Traits, _Allocator>&
    2608              : >
    2609              : basic_string<_CharT, _Traits, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
    2610              : {
    2611              :     size_type __cap = capacity();
    2612              :     size_type __n = __string_is_trivial_iterator<_ForwardIterator>::value ?
    2613              :         static_cast<size_type>(std::distance(__first, __last)) : 0;
    2614              : 
    2615              :     if (__string_is_trivial_iterator<_ForwardIterator>::value &&
    2616              :         (__cap >= __n || !__addr_in_range(*__first)))
    2617              :     {
    2618              :         if (__cap < __n)
    2619              :         {
    2620              :             size_type __sz = size();
    2621              :             __grow_by(__cap, __n - __cap, __sz, 0, __sz);
    2622              :         }
    2623              :         pointer __p = __get_pointer();
    2624              :         for (; __first != __last; ++__p, (void) ++__first)
    2625              :             traits_type::assign(*__p, *__first);
    2626              :         traits_type::assign(*__p, value_type());
    2627              :         __set_size(__n);
    2628              :         __invalidate_iterators_past(__n);
    2629              :     }
    2630              :     else
    2631              :     {
    2632              :         const basic_string __temp(__first, __last, __alloc());
    2633              :         assign(__temp.data(), __temp.size());
    2634              :     }
    2635              :     return *this;
    2636              : }
    2637              : 
    2638              : template <class _CharT, class _Traits, class _Allocator>
    2639              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2640              : basic_string<_CharT, _Traits, _Allocator>&
    2641              : basic_string<_CharT, _Traits, _Allocator>::assign(const basic_string& __str, size_type __pos, size_type __n)
    2642              : {
    2643              :     size_type __sz = __str.size();
    2644              :     if (__pos > __sz)
    2645              :         __throw_out_of_range();
    2646              :     return assign(__str.data() + __pos, std::min(__n, __sz - __pos));
    2647              : }
    2648              : 
    2649              : template <class _CharT, class _Traits, class _Allocator>
    2650              : template <class _Tp>
    2651              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2652              : __enable_if_t
    2653              : <
    2654              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
    2655              :     && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
    2656              :     basic_string<_CharT, _Traits, _Allocator>&
    2657              : >
    2658              : basic_string<_CharT, _Traits, _Allocator>::assign(const _Tp & __t, size_type __pos, size_type __n)
    2659              : {
    2660              :     __self_view __sv = __t;
    2661              :     size_type __sz = __sv.size();
    2662              :     if (__pos > __sz)
    2663              :         __throw_out_of_range();
    2664              :     return assign(__sv.data() + __pos, std::min(__n, __sz - __pos));
    2665              : }
    2666              : 
    2667              : 
    2668              : template <class _CharT, class _Traits, class _Allocator>
    2669              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2670              : basic_string<_CharT, _Traits, _Allocator>&
    2671              : basic_string<_CharT, _Traits, _Allocator>::__assign_external(const value_type* __s) {
    2672              :   return __assign_external(__s, traits_type::length(__s));
    2673              : }
    2674              : 
    2675              : template <class _CharT, class _Traits, class _Allocator>
    2676              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2677              : basic_string<_CharT, _Traits, _Allocator>&
    2678              : basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s)
    2679              : {
    2680              :     _LIBCPP_ASSERT(__s != nullptr, "string::assign received nullptr");
    2681              :     return __builtin_constant_p(*__s)
    2682              :                ? (__fits_in_sso(traits_type::length(__s))
    2683              :                       ? __assign_short(__s, traits_type::length(__s))
    2684              :                       : __assign_external(__s, traits_type::length(__s)))
    2685              :                : __assign_external(__s);
    2686              : }
    2687              : // append
    2688              : 
    2689              : template <class _CharT, class _Traits, class _Allocator>
    2690              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2691              : basic_string<_CharT, _Traits, _Allocator>&
    2692              : basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s, size_type __n)
    2693              : {
    2694              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::append received nullptr");
    2695              :     size_type __cap = capacity();
    2696              :     size_type __sz = size();
    2697              :     if (__cap - __sz >= __n)
    2698              :     {
    2699              :         if (__n)
    2700              :         {
    2701              :             value_type* __p = std::__to_address(__get_pointer());
    2702              :             traits_type::copy(__p + __sz, __s, __n);
    2703              :             __sz += __n;
    2704              :             __set_size(__sz);
    2705              :             traits_type::assign(__p[__sz], value_type());
    2706              :         }
    2707              :     }
    2708              :     else
    2709              :         __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __sz, 0, __n, __s);
    2710              :     return *this;
    2711              : }
    2712              : 
    2713              : template <class _CharT, class _Traits, class _Allocator>
    2714              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2715              : basic_string<_CharT, _Traits, _Allocator>&
    2716              : basic_string<_CharT, _Traits, _Allocator>::append(size_type __n, value_type __c)
    2717              : {
    2718              :     if (__n)
    2719              :     {
    2720              :         size_type __cap = capacity();
    2721              :         size_type __sz = size();
    2722              :         if (__cap - __sz < __n)
    2723              :             __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
    2724              :         pointer __p = __get_pointer();
    2725              :         traits_type::assign(std::__to_address(__p) + __sz, __n, __c);
    2726              :         __sz += __n;
    2727              :         __set_size(__sz);
    2728              :         traits_type::assign(__p[__sz], value_type());
    2729              :     }
    2730              :     return *this;
    2731              : }
    2732              : 
    2733              : template <class _CharT, class _Traits, class _Allocator>
    2734              : _LIBCPP_CONSTEXPR_SINCE_CXX20 inline void
    2735              : basic_string<_CharT, _Traits, _Allocator>::__append_default_init(size_type __n)
    2736              : {
    2737              :     if (__n)
    2738              :     {
    2739              :         size_type __cap = capacity();
    2740              :         size_type __sz = size();
    2741              :         if (__cap - __sz < __n)
    2742              :             __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
    2743              :         pointer __p = __get_pointer();
    2744              :         __sz += __n;
    2745              :         __set_size(__sz);
    2746              :         traits_type::assign(__p[__sz], value_type());
    2747              :     }
    2748              : }
    2749              : 
    2750              : template <class _CharT, class _Traits, class _Allocator>
    2751              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2752              : void
    2753              : basic_string<_CharT, _Traits, _Allocator>::push_back(value_type __c)
    2754              : {
    2755              :     bool __is_short = !__is_long();
    2756              :     size_type __cap;
    2757              :     size_type __sz;
    2758              :     if (__is_short)
    2759              :     {
    2760              :         __cap = __min_cap - 1;
    2761              :         __sz = __get_short_size();
    2762              :     }
    2763              :     else
    2764              :     {
    2765              :         __cap = __get_long_cap() - 1;
    2766              :         __sz = __get_long_size();
    2767              :     }
    2768              :     if (__sz == __cap)
    2769              :     {
    2770              :         __grow_by(__cap, 1, __sz, __sz, 0);
    2771              :         __is_short = false; // the string is always long after __grow_by
    2772              :     }
    2773              :     pointer __p = __get_pointer();
    2774              :     if (__is_short)
    2775              :     {
    2776              :         __p = __get_short_pointer() + __sz;
    2777              :         __set_short_size(__sz+1);
    2778              :     }
    2779              :     else
    2780              :     {
    2781              :         __p = __get_long_pointer() + __sz;
    2782              :         __set_long_size(__sz+1);
    2783              :     }
    2784              :     traits_type::assign(*__p, __c);
    2785              :     traits_type::assign(*++__p, value_type());
    2786              : }
    2787              : 
    2788              : template <class _CharT, class _Traits, class _Allocator>
    2789              : template<class _ForwardIterator>
    2790              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2791              : __enable_if_t
    2792              : <
    2793              :     __is_cpp17_forward_iterator<_ForwardIterator>::value,
    2794              :     basic_string<_CharT, _Traits, _Allocator>&
    2795              : >
    2796              : basic_string<_CharT, _Traits, _Allocator>::append(
    2797              :     _ForwardIterator __first, _ForwardIterator __last)
    2798              : {
    2799              :     size_type __sz = size();
    2800              :     size_type __cap = capacity();
    2801              :     size_type __n = static_cast<size_type>(std::distance(__first, __last));
    2802              :     if (__n)
    2803              :     {
    2804              :         if (__string_is_trivial_iterator<_ForwardIterator>::value &&
    2805              :             !__addr_in_range(*__first))
    2806              :         {
    2807              :             if (__cap - __sz < __n)
    2808              :                 __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
    2809              :             pointer __p = __get_pointer() + __sz;
    2810              :             for (; __first != __last; ++__p, (void) ++__first)
    2811              :                 traits_type::assign(*__p, *__first);
    2812              :             traits_type::assign(*__p, value_type());
    2813              :             __set_size(__sz + __n);
    2814              :         }
    2815              :         else
    2816              :         {
    2817              :             const basic_string __temp(__first, __last, __alloc());
    2818              :             append(__temp.data(), __temp.size());
    2819              :         }
    2820              :     }
    2821              :     return *this;
    2822              : }
    2823              : 
    2824              : template <class _CharT, class _Traits, class _Allocator>
    2825              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2826              : basic_string<_CharT, _Traits, _Allocator>&
    2827              : basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str, size_type __pos, size_type __n)
    2828              : {
    2829              :     size_type __sz = __str.size();
    2830              :     if (__pos > __sz)
    2831              :         __throw_out_of_range();
    2832              :     return append(__str.data() + __pos, std::min(__n, __sz - __pos));
    2833              : }
    2834              : 
    2835              : template <class _CharT, class _Traits, class _Allocator>
    2836              : template <class _Tp>
    2837              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2838              :     __enable_if_t
    2839              :     <
    2840              :         __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value  && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
    2841              :         basic_string<_CharT, _Traits, _Allocator>&
    2842              :     >
    2843              : basic_string<_CharT, _Traits, _Allocator>::append(const _Tp & __t, size_type __pos, size_type __n)
    2844              : {
    2845              :     __self_view __sv = __t;
    2846              :     size_type __sz = __sv.size();
    2847              :     if (__pos > __sz)
    2848              :         __throw_out_of_range();
    2849              :     return append(__sv.data() + __pos, std::min(__n, __sz - __pos));
    2850              : }
    2851              : 
    2852              : template <class _CharT, class _Traits, class _Allocator>
    2853              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2854              : basic_string<_CharT, _Traits, _Allocator>&
    2855              : basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s)
    2856              : {
    2857              :     _LIBCPP_ASSERT(__s != nullptr, "string::append received nullptr");
    2858              :     return append(__s, traits_type::length(__s));
    2859              : }
    2860              : 
    2861              : // insert
    2862              : 
    2863              : template <class _CharT, class _Traits, class _Allocator>
    2864              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2865              : basic_string<_CharT, _Traits, _Allocator>&
    2866              : basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s, size_type __n)
    2867              : {
    2868              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::insert received nullptr");
    2869              :     size_type __sz = size();
    2870              :     if (__pos > __sz)
    2871              :         __throw_out_of_range();
    2872              :     size_type __cap = capacity();
    2873              :     if (__libcpp_is_constant_evaluated()) {
    2874              :         if (__cap - __sz >= __n)
    2875              :             __grow_by_and_replace(__cap, 0, __sz, __pos, 0, __n, __s);
    2876              :         else
    2877              :             __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __pos, 0, __n, __s);
    2878              :         return *this;
    2879              :     }
    2880              :     if (__cap - __sz >= __n)
    2881              :     {
    2882              :         if (__n)
    2883              :         {
    2884              :             value_type* __p = std::__to_address(__get_pointer());
    2885              :             size_type __n_move = __sz - __pos;
    2886              :             if (__n_move != 0)
    2887              :             {
    2888              :                 if (__p + __pos <= __s && __s < __p + __sz)
    2889              :                     __s += __n;
    2890              :                 traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
    2891              :             }
    2892              :             traits_type::move(__p + __pos, __s, __n);
    2893              :             __sz += __n;
    2894              :             __set_size(__sz);
    2895              :             traits_type::assign(__p[__sz], value_type());
    2896              :         }
    2897              :     }
    2898              :     else
    2899              :         __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __pos, 0, __n, __s);
    2900              :     return *this;
    2901              : }
    2902              : 
    2903              : template <class _CharT, class _Traits, class _Allocator>
    2904              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2905              : basic_string<_CharT, _Traits, _Allocator>&
    2906              : basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, size_type __n, value_type __c)
    2907              : {
    2908              :     size_type __sz = size();
    2909              :     if (__pos > __sz)
    2910              :         __throw_out_of_range();
    2911              :     if (__n)
    2912              :     {
    2913              :         size_type __cap = capacity();
    2914              :         value_type* __p;
    2915              :         if (__cap - __sz >= __n)
    2916              :         {
    2917              :             __p = std::__to_address(__get_pointer());
    2918              :             size_type __n_move = __sz - __pos;
    2919              :             if (__n_move != 0)
    2920              :                 traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
    2921              :         }
    2922              :         else
    2923              :         {
    2924              :             __grow_by(__cap, __sz + __n - __cap, __sz, __pos, 0, __n);
    2925              :             __p = std::__to_address(__get_long_pointer());
    2926              :         }
    2927              :         traits_type::assign(__p + __pos, __n, __c);
    2928              :         __sz += __n;
    2929              :         __set_size(__sz);
    2930              :         traits_type::assign(__p[__sz], value_type());
    2931              :     }
    2932              :     return *this;
    2933              : }
    2934              : 
    2935              : template <class _CharT, class _Traits, class _Allocator>
    2936              : template<class _InputIterator>
    2937              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2938              : __enable_if_t
    2939              : <
    2940              :    __is_exactly_cpp17_input_iterator<_InputIterator>::value,
    2941              :    typename basic_string<_CharT, _Traits, _Allocator>::iterator
    2942              : >
    2943              : basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _InputIterator __first, _InputIterator __last)
    2944              : {
    2945              :   _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
    2946              :                        "string::insert(iterator, range) called with an iterator not"
    2947              :                        " referring to this string");
    2948              :   const basic_string __temp(__first, __last, __alloc());
    2949              :   return insert(__pos, __temp.data(), __temp.data() + __temp.size());
    2950              : }
    2951              : 
    2952              : template <class _CharT, class _Traits, class _Allocator>
    2953              : template<class _ForwardIterator>
    2954              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2955              : __enable_if_t
    2956              : <
    2957              :     __is_cpp17_forward_iterator<_ForwardIterator>::value,
    2958              :     typename basic_string<_CharT, _Traits, _Allocator>::iterator
    2959              : >
    2960              : basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last)
    2961              : {
    2962              :     _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
    2963              :                          "string::insert(iterator, range) called with an iterator not referring to this string");
    2964              : 
    2965              :     size_type __ip = static_cast<size_type>(__pos - begin());
    2966              :     size_type __n = static_cast<size_type>(std::distance(__first, __last));
    2967              :     if (__n == 0)
    2968              :         return begin() + __ip;
    2969              : 
    2970              :     if (__string_is_trivial_iterator<_ForwardIterator>::value && !__addr_in_range(*__first))
    2971              :     {
    2972              :         return __insert_from_safe_copy(__n, __ip, __first, __last);
    2973              :     }
    2974              :     else
    2975              :     {
    2976              :         const basic_string __temp(__first, __last, __alloc());
    2977              :         return __insert_from_safe_copy(__n, __ip, __temp.begin(), __temp.end());
    2978              :     }
    2979              : }
    2980              : 
    2981              : template <class _CharT, class _Traits, class _Allocator>
    2982              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2983              : basic_string<_CharT, _Traits, _Allocator>&
    2984              : basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str,
    2985              :                                                   size_type __pos2, size_type __n)
    2986              : {
    2987              :     size_type __str_sz = __str.size();
    2988              :     if (__pos2 > __str_sz)
    2989              :         __throw_out_of_range();
    2990              :     return insert(__pos1, __str.data() + __pos2, std::min(__n, __str_sz - __pos2));
    2991              : }
    2992              : 
    2993              : template <class _CharT, class _Traits, class _Allocator>
    2994              : template <class _Tp>
    2995              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    2996              : __enable_if_t
    2997              : <
    2998              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value  && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
    2999              :     basic_string<_CharT, _Traits, _Allocator>&
    3000              : >
    3001              : basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const _Tp& __t,
    3002              :                                                   size_type __pos2, size_type __n)
    3003              : {
    3004              :     __self_view __sv = __t;
    3005              :     size_type __str_sz = __sv.size();
    3006              :     if (__pos2 > __str_sz)
    3007              :         __throw_out_of_range();
    3008              :     return insert(__pos1, __sv.data() + __pos2, std::min(__n, __str_sz - __pos2));
    3009              : }
    3010              : 
    3011              : template <class _CharT, class _Traits, class _Allocator>
    3012              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3013              : basic_string<_CharT, _Traits, _Allocator>&
    3014              : basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s)
    3015              : {
    3016              :     _LIBCPP_ASSERT(__s != nullptr, "string::insert received nullptr");
    3017              :     return insert(__pos, __s, traits_type::length(__s));
    3018              : }
    3019              : 
    3020              : template <class _CharT, class _Traits, class _Allocator>
    3021              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3022              : typename basic_string<_CharT, _Traits, _Allocator>::iterator
    3023              : basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, value_type __c)
    3024              : {
    3025              :     _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
    3026              :                          "string::insert(iterator, character) called with an iterator not"
    3027              :                          " referring to this string");
    3028              : 
    3029              :     size_type __ip = static_cast<size_type>(__pos - begin());
    3030              :     size_type __sz = size();
    3031              :     size_type __cap = capacity();
    3032              :     value_type* __p;
    3033              :     if (__cap == __sz)
    3034              :     {
    3035              :         __grow_by(__cap, 1, __sz, __ip, 0, 1);
    3036              :         __p = std::__to_address(__get_long_pointer());
    3037              :     }
    3038              :     else
    3039              :     {
    3040              :         __p = std::__to_address(__get_pointer());
    3041              :         size_type __n_move = __sz - __ip;
    3042              :         if (__n_move != 0)
    3043              :             traits_type::move(__p + __ip + 1, __p + __ip, __n_move);
    3044              :     }
    3045              :     traits_type::assign(__p[__ip], __c);
    3046              :     traits_type::assign(__p[++__sz], value_type());
    3047              :     __set_size(__sz);
    3048              :     return begin() + static_cast<difference_type>(__ip);
    3049              : }
    3050              : 
    3051              : // replace
    3052              : 
    3053              : template <class _CharT, class _Traits, class _Allocator>
    3054              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3055              : basic_string<_CharT, _Traits, _Allocator>&
    3056              : basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2)
    3057              :     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
    3058              : {
    3059              :     _LIBCPP_ASSERT(__n2 == 0 || __s != nullptr, "string::replace received nullptr");
    3060              :     size_type __sz = size();
    3061              :     if (__pos > __sz)
    3062              :         __throw_out_of_range();
    3063              :     __n1 = std::min(__n1, __sz - __pos);
    3064              :     size_type __cap = capacity();
    3065              :     if (__cap - __sz + __n1 >= __n2)
    3066              :     {
    3067              :         if (__libcpp_is_constant_evaluated()) {
    3068              :             __grow_by_and_replace(__cap, 0, __sz, __pos, __n1, __n2, __s);
    3069              :             return *this;
    3070              :         }
    3071              :         value_type* __p = std::__to_address(__get_pointer());
    3072              :         if (__n1 != __n2)
    3073              :         {
    3074              :             size_type __n_move = __sz - __pos - __n1;
    3075              :             if (__n_move != 0)
    3076              :             {
    3077              :                 if (__n1 > __n2)
    3078              :                 {
    3079              :                     traits_type::move(__p + __pos, __s, __n2);
    3080              :                     traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
    3081              :                     return __null_terminate_at(__p, __sz + (__n2 - __n1));
    3082              :                 }
    3083              :                 if (__p + __pos < __s && __s < __p + __sz)
    3084              :                 {
    3085              :                     if (__p + __pos + __n1 <= __s)
    3086              :                         __s += __n2 - __n1;
    3087              :                     else // __p + __pos < __s < __p + __pos + __n1
    3088              :                     {
    3089              :                         traits_type::move(__p + __pos, __s, __n1);
    3090              :                         __pos += __n1;
    3091              :                         __s += __n2;
    3092              :                         __n2 -= __n1;
    3093              :                         __n1 = 0;
    3094              :                     }
    3095              :                 }
    3096              :                 traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
    3097              :             }
    3098              :         }
    3099              :         traits_type::move(__p + __pos, __s, __n2);
    3100              :         return __null_terminate_at(__p, __sz + (__n2 - __n1));
    3101              :     }
    3102              :     else
    3103              :         __grow_by_and_replace(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2, __s);
    3104              :     return *this;
    3105              : }
    3106              : 
    3107              : template <class _CharT, class _Traits, class _Allocator>
    3108              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3109              : basic_string<_CharT, _Traits, _Allocator>&
    3110              : basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, size_type __n2, value_type __c)
    3111              : {
    3112              :     size_type __sz = size();
    3113              :     if (__pos > __sz)
    3114              :         __throw_out_of_range();
    3115              :     __n1 = std::min(__n1, __sz - __pos);
    3116              :     size_type __cap = capacity();
    3117              :     value_type* __p;
    3118              :     if (__cap - __sz + __n1 >= __n2)
    3119              :     {
    3120              :         __p = std::__to_address(__get_pointer());
    3121              :         if (__n1 != __n2)
    3122              :         {
    3123              :             size_type __n_move = __sz - __pos - __n1;
    3124              :             if (__n_move != 0)
    3125              :                 traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
    3126              :         }
    3127              :     }
    3128              :     else
    3129              :     {
    3130              :         __grow_by(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2);
    3131              :         __p = std::__to_address(__get_long_pointer());
    3132              :     }
    3133              :     traits_type::assign(__p + __pos, __n2, __c);
    3134              :     return __null_terminate_at(__p, __sz - (__n1 - __n2));
    3135              : }
    3136              : 
    3137              : template <class _CharT, class _Traits, class _Allocator>
    3138              : template<class _InputIterator>
    3139              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3140              : __enable_if_t
    3141              : <
    3142              :     __is_cpp17_input_iterator<_InputIterator>::value,
    3143              :     basic_string<_CharT, _Traits, _Allocator>&
    3144              : >
    3145              : basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2,
    3146              :                                                    _InputIterator __j1, _InputIterator __j2)
    3147              : {
    3148              :     const basic_string __temp(__j1, __j2, __alloc());
    3149              :     return replace(__i1, __i2, __temp);
    3150              : }
    3151              : 
    3152              : template <class _CharT, class _Traits, class _Allocator>
    3153              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3154              : basic_string<_CharT, _Traits, _Allocator>&
    3155              : basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const basic_string& __str,
    3156              :                                                    size_type __pos2, size_type __n2)
    3157              : {
    3158              :     size_type __str_sz = __str.size();
    3159              :     if (__pos2 > __str_sz)
    3160              :         __throw_out_of_range();
    3161              :     return replace(__pos1, __n1, __str.data() + __pos2, std::min(__n2, __str_sz - __pos2));
    3162              : }
    3163              : 
    3164              : template <class _CharT, class _Traits, class _Allocator>
    3165              : template <class _Tp>
    3166              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3167              : __enable_if_t
    3168              : <
    3169              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
    3170              :     basic_string<_CharT, _Traits, _Allocator>&
    3171              : >
    3172              : basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const _Tp& __t,
    3173              :                                                    size_type __pos2, size_type __n2)
    3174              : {
    3175              :     __self_view __sv = __t;
    3176              :     size_type __str_sz = __sv.size();
    3177              :     if (__pos2 > __str_sz)
    3178              :         __throw_out_of_range();
    3179              :     return replace(__pos1, __n1, __sv.data() + __pos2, std::min(__n2, __str_sz - __pos2));
    3180              : }
    3181              : 
    3182              : template <class _CharT, class _Traits, class _Allocator>
    3183              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3184              : basic_string<_CharT, _Traits, _Allocator>&
    3185              : basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s)
    3186              : {
    3187              :     _LIBCPP_ASSERT(__s != nullptr, "string::replace received nullptr");
    3188              :     return replace(__pos, __n1, __s, traits_type::length(__s));
    3189              : }
    3190              : 
    3191              : // erase
    3192              : 
    3193              : // 'externally instantiated' erase() implementation, called when __n != npos.
    3194              : // Does not check __pos against size()
    3195              : template <class _CharT, class _Traits, class _Allocator>
    3196              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3197              : void
    3198              : basic_string<_CharT, _Traits, _Allocator>::__erase_external_with_move(
    3199              :     size_type __pos, size_type __n)
    3200              : {
    3201              :     if (__n)
    3202              :     {
    3203              :         size_type __sz = size();
    3204              :         value_type* __p = std::__to_address(__get_pointer());
    3205              :         __n = std::min(__n, __sz - __pos);
    3206              :         size_type __n_move = __sz - __pos - __n;
    3207              :         if (__n_move != 0)
    3208              :             traits_type::move(__p + __pos, __p + __pos + __n, __n_move);
    3209              :         __null_terminate_at(__p, __sz - __n);
    3210              :     }
    3211              : }
    3212              : 
    3213              : template <class _CharT, class _Traits, class _Allocator>
    3214              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3215              : basic_string<_CharT, _Traits, _Allocator>&
    3216              : basic_string<_CharT, _Traits, _Allocator>::erase(size_type __pos,
    3217              :                                                  size_type __n) {
    3218              :   if (__pos > size())
    3219              :     __throw_out_of_range();
    3220              :   if (__n == npos) {
    3221              :     __erase_to_end(__pos);
    3222              :   } else {
    3223              :     __erase_external_with_move(__pos, __n);
    3224              :   }
    3225              :   return *this;
    3226              : }
    3227              : 
    3228              : template <class _CharT, class _Traits, class _Allocator>
    3229              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3230              : typename basic_string<_CharT, _Traits, _Allocator>::iterator
    3231              : basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __pos)
    3232              : {
    3233              :   _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
    3234              :                        "string::erase(iterator) called with an iterator not"
    3235              :                        " referring to this string");
    3236              : 
    3237              :   _LIBCPP_ASSERT(__pos != end(), "string::erase(iterator) called with a non-dereferenceable iterator");
    3238              :   iterator __b = begin();
    3239              :   size_type __r = static_cast<size_type>(__pos - __b);
    3240              :   erase(__r, 1);
    3241              :   return __b + static_cast<difference_type>(__r);
    3242              : }
    3243              : 
    3244              : template <class _CharT, class _Traits, class _Allocator>
    3245              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3246              : typename basic_string<_CharT, _Traits, _Allocator>::iterator
    3247              : basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __first, const_iterator __last)
    3248              : {
    3249              :   _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
    3250              :                        "string::erase(iterator,  iterator) called with an iterator not"
    3251              :                        " referring to this string");
    3252              : 
    3253              :   _LIBCPP_ASSERT(__first <= __last, "string::erase(first, last) called with invalid range");
    3254              :   iterator __b = begin();
    3255              :   size_type __r = static_cast<size_type>(__first - __b);
    3256              :   erase(__r, static_cast<size_type>(__last - __first));
    3257              :   return __b + static_cast<difference_type>(__r);
    3258              : }
    3259              : 
    3260              : template <class _CharT, class _Traits, class _Allocator>
    3261              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3262              : void
    3263              : basic_string<_CharT, _Traits, _Allocator>::pop_back()
    3264              : {
    3265              :     _LIBCPP_ASSERT(!empty(), "string::pop_back(): string is already empty");
    3266              :     __erase_to_end(size() - 1);
    3267              : }
    3268              : 
    3269              : template <class _CharT, class _Traits, class _Allocator>
    3270              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3271              : void
    3272          749 : basic_string<_CharT, _Traits, _Allocator>::clear() _NOEXCEPT
    3273              : {
    3274          749 :     std::__debug_db_invalidate_all(this);
    3275          749 :     if (__is_long())
    3276              :     {
    3277            0 :         traits_type::assign(*__get_long_pointer(), value_type());
    3278            0 :         __set_long_size(0);
    3279            0 :     }
    3280              :     else
    3281              :     {
    3282          749 :         traits_type::assign(*__get_short_pointer(), value_type());
    3283          749 :         __set_short_size(0);
    3284              :     }
    3285          749 : }
    3286              : 
    3287              : template <class _CharT, class _Traits, class _Allocator>
    3288              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3289              : void
    3290              : basic_string<_CharT, _Traits, _Allocator>::resize(size_type __n, value_type __c)
    3291              : {
    3292              :     size_type __sz = size();
    3293              :     if (__n > __sz)
    3294              :         append(__n - __sz, __c);
    3295              :     else
    3296              :         __erase_to_end(__n);
    3297              : }
    3298              : 
    3299              : template <class _CharT, class _Traits, class _Allocator>
    3300              : _LIBCPP_CONSTEXPR_SINCE_CXX20 inline void
    3301              : basic_string<_CharT, _Traits, _Allocator>::__resize_default_init(size_type __n)
    3302              : {
    3303              :     size_type __sz = size();
    3304              :     if (__n > __sz) {
    3305              :        __append_default_init(__n - __sz);
    3306              :     } else
    3307              :         __erase_to_end(__n);
    3308              : }
    3309              : 
    3310              : template <class _CharT, class _Traits, class _Allocator>
    3311              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3312              : void
    3313              : basic_string<_CharT, _Traits, _Allocator>::reserve(size_type __requested_capacity)
    3314              : {
    3315              :     if (__requested_capacity > max_size())
    3316              :         __throw_length_error();
    3317              : 
    3318              :     // Make sure reserve(n) never shrinks. This is technically only required in C++20
    3319              :     // and later (since P0966R1), however we provide consistent behavior in all Standard
    3320              :     // modes because this function is instantiated in the shared library.
    3321              :     if (__requested_capacity <= capacity())
    3322              :         return;
    3323              : 
    3324              :     size_type __target_capacity = std::max(__requested_capacity, size());
    3325              :     __target_capacity = __recommend(__target_capacity);
    3326              :     if (__target_capacity == capacity()) return;
    3327              : 
    3328              :     __shrink_or_extend(__target_capacity);
    3329              : }
    3330              : 
    3331              : template <class _CharT, class _Traits, class _Allocator>
    3332              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3333              : void
    3334              : basic_string<_CharT, _Traits, _Allocator>::shrink_to_fit() _NOEXCEPT
    3335              : {
    3336              :     size_type __target_capacity = __recommend(size());
    3337              :     if (__target_capacity == capacity()) return;
    3338              : 
    3339              :     __shrink_or_extend(__target_capacity);
    3340              : }
    3341              : 
    3342              : template <class _CharT, class _Traits, class _Allocator>
    3343              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3344              : void
    3345              : basic_string<_CharT, _Traits, _Allocator>::__shrink_or_extend(size_type __target_capacity)
    3346              : {
    3347              :     size_type __cap = capacity();
    3348              :     size_type __sz = size();
    3349              : 
    3350              :     pointer __new_data, __p;
    3351              :     bool __was_long, __now_long;
    3352              :     if (__fits_in_sso(__target_capacity))
    3353              :     {
    3354              :         __was_long = true;
    3355              :         __now_long = false;
    3356              :         __new_data = __get_short_pointer();
    3357              :         __p = __get_long_pointer();
    3358              :     }
    3359              :     else
    3360              :     {
    3361              :         if (__target_capacity > __cap) {
    3362              :             auto __allocation = std::__allocate_at_least(__alloc(), __target_capacity + 1);
    3363              :             __new_data = __allocation.ptr;
    3364              :             __target_capacity = __allocation.count - 1;
    3365              :         }
    3366              :         else
    3367              :         {
    3368              :         #ifndef _LIBCPP_NO_EXCEPTIONS
    3369              :             try
    3370              :             {
    3371              :         #endif // _LIBCPP_NO_EXCEPTIONS
    3372              :                 auto __allocation = std::__allocate_at_least(__alloc(), __target_capacity + 1);
    3373              :                 __new_data = __allocation.ptr;
    3374              :                 __target_capacity = __allocation.count - 1;
    3375              :         #ifndef _LIBCPP_NO_EXCEPTIONS
    3376              :             }
    3377              :             catch (...)
    3378              :             {
    3379              :                 return;
    3380              :             }
    3381              :         #else  // _LIBCPP_NO_EXCEPTIONS
    3382              :             if (__new_data == nullptr)
    3383              :                 return;
    3384              :         #endif // _LIBCPP_NO_EXCEPTIONS
    3385              :         }
    3386              :         __begin_lifetime(__new_data, __target_capacity + 1);
    3387              :         __now_long = true;
    3388              :         __was_long = __is_long();
    3389              :         __p = __get_pointer();
    3390              :     }
    3391              :     traits_type::copy(std::__to_address(__new_data),
    3392              :                       std::__to_address(__p), size()+1);
    3393              :     if (__was_long)
    3394              :         __alloc_traits::deallocate(__alloc(), __p, __cap+1);
    3395              :     if (__now_long)
    3396              :     {
    3397              :         __set_long_cap(__target_capacity+1);
    3398              :         __set_long_size(__sz);
    3399              :         __set_long_pointer(__new_data);
    3400              :     }
    3401              :     else
    3402              :         __set_short_size(__sz);
    3403              :     std::__debug_db_invalidate_all(this);
    3404              : }
    3405              : 
    3406              : template <class _CharT, class _Traits, class _Allocator>
    3407              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3408              : typename basic_string<_CharT, _Traits, _Allocator>::const_reference
    3409              : basic_string<_CharT, _Traits, _Allocator>::at(size_type __n) const
    3410              : {
    3411              :     if (__n >= size())
    3412              :         __throw_out_of_range();
    3413              :     return (*this)[__n];
    3414              : }
    3415              : 
    3416              : template <class _CharT, class _Traits, class _Allocator>
    3417              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3418              : typename basic_string<_CharT, _Traits, _Allocator>::reference
    3419              : basic_string<_CharT, _Traits, _Allocator>::at(size_type __n)
    3420              : {
    3421              :     if (__n >= size())
    3422              :         __throw_out_of_range();
    3423              :     return (*this)[__n];
    3424              : }
    3425              : 
    3426              : template <class _CharT, class _Traits, class _Allocator>
    3427              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3428              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3429              : basic_string<_CharT, _Traits, _Allocator>::copy(value_type* __s, size_type __n, size_type __pos) const
    3430              : {
    3431              :     size_type __sz = size();
    3432              :     if (__pos > __sz)
    3433              :         __throw_out_of_range();
    3434              :     size_type __rlen = std::min(__n, __sz - __pos);
    3435              :     traits_type::copy(__s, data() + __pos, __rlen);
    3436              :     return __rlen;
    3437              : }
    3438              : 
    3439              : template <class _CharT, class _Traits, class _Allocator>
    3440              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3441              : void
    3442              : basic_string<_CharT, _Traits, _Allocator>::swap(basic_string& __str)
    3443              : #if _LIBCPP_STD_VER >= 14
    3444              :         _NOEXCEPT
    3445              : #else
    3446              :         _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
    3447              :                     __is_nothrow_swappable<allocator_type>::value)
    3448              : #endif
    3449              : {
    3450              :     if (!__is_long())
    3451              :         std::__debug_db_invalidate_all(this);
    3452              :     if (!__str.__is_long())
    3453              :         std::__debug_db_invalidate_all(&__str);
    3454              :     std::__debug_db_swap(this, &__str);
    3455              : 
    3456              :     _LIBCPP_ASSERT(
    3457              :         __alloc_traits::propagate_on_container_swap::value ||
    3458              :         __alloc_traits::is_always_equal::value ||
    3459              :         __alloc() == __str.__alloc(), "swapping non-equal allocators");
    3460              :     std::swap(__r_.first(), __str.__r_.first());
    3461              :     std::__swap_allocator(__alloc(), __str.__alloc());
    3462              : }
    3463              : 
    3464              : // find
    3465              : 
    3466              : template <class _Traits>
    3467              : struct _LIBCPP_HIDDEN __traits_eq
    3468              : {
    3469              :     typedef typename _Traits::char_type char_type;
    3470              :     _LIBCPP_HIDE_FROM_ABI
    3471              :     bool operator()(const char_type& __x, const char_type& __y) _NOEXCEPT
    3472              :         {return _Traits::eq(__x, __y);}
    3473              : };
    3474              : 
    3475              : template<class _CharT, class _Traits, class _Allocator>
    3476              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3477              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3478              : basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
    3479              :                                                 size_type __pos,
    3480              :                                                 size_type __n) const _NOEXCEPT
    3481              : {
    3482              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find(): received nullptr");
    3483              :     return std::__str_find<value_type, size_type, traits_type, npos>
    3484              :         (data(), size(), __s, __pos, __n);
    3485              : }
    3486              : 
    3487              : template<class _CharT, class _Traits, class _Allocator>
    3488              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3489              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3490              : basic_string<_CharT, _Traits, _Allocator>::find(const basic_string& __str,
    3491              :                                                 size_type __pos) const _NOEXCEPT
    3492              : {
    3493              :     return std::__str_find<value_type, size_type, traits_type, npos>
    3494              :         (data(), size(), __str.data(), __pos, __str.size());
    3495              : }
    3496              : 
    3497              : template<class _CharT, class _Traits, class _Allocator>
    3498              : template <class _Tp>
    3499              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3500              : __enable_if_t
    3501              : <
    3502              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    3503              :     typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3504              : >
    3505              : basic_string<_CharT, _Traits, _Allocator>::find(const _Tp &__t,
    3506              :                                                 size_type __pos) const _NOEXCEPT
    3507              : {
    3508              :     __self_view __sv = __t;
    3509              :     return std::__str_find<value_type, size_type, traits_type, npos>
    3510              :         (data(), size(), __sv.data(), __pos, __sv.size());
    3511              : }
    3512              : 
    3513              : template<class _CharT, class _Traits, class _Allocator>
    3514              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3515              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3516        13945 : basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
    3517              :                                                 size_type __pos) const _NOEXCEPT
    3518              : {
    3519        13945 :     _LIBCPP_ASSERT(__s != nullptr, "string::find(): received nullptr");
    3520        13945 :     return std::__str_find<value_type, size_type, traits_type, npos>
    3521        13945 :         (data(), size(), __s, __pos, traits_type::length(__s));
    3522              : }
    3523              : 
    3524              : template<class _CharT, class _Traits, class _Allocator>
    3525              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3526              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3527              : basic_string<_CharT, _Traits, _Allocator>::find(value_type __c,
    3528              :                                                 size_type __pos) const _NOEXCEPT
    3529              : {
    3530              :     return std::__str_find<value_type, size_type, traits_type, npos>
    3531              :         (data(), size(), __c, __pos);
    3532              : }
    3533              : 
    3534              : // rfind
    3535              : 
    3536              : template<class _CharT, class _Traits, class _Allocator>
    3537              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3538              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3539              : basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
    3540              :                                                  size_type __pos,
    3541              :                                                  size_type __n) const _NOEXCEPT
    3542              : {
    3543              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::rfind(): received nullptr");
    3544              :     return std::__str_rfind<value_type, size_type, traits_type, npos>
    3545              :         (data(), size(), __s, __pos, __n);
    3546              : }
    3547              : 
    3548              : template<class _CharT, class _Traits, class _Allocator>
    3549              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3550              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3551              : basic_string<_CharT, _Traits, _Allocator>::rfind(const basic_string& __str,
    3552              :                                                  size_type __pos) const _NOEXCEPT
    3553              : {
    3554              :     return std::__str_rfind<value_type, size_type, traits_type, npos>
    3555              :         (data(), size(), __str.data(), __pos, __str.size());
    3556              : }
    3557              : 
    3558              : template<class _CharT, class _Traits, class _Allocator>
    3559              : template <class _Tp>
    3560              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3561              : __enable_if_t
    3562              : <
    3563              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    3564              :     typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3565              : >
    3566              : basic_string<_CharT, _Traits, _Allocator>::rfind(const _Tp& __t,
    3567              :                                                 size_type __pos) const _NOEXCEPT
    3568              : {
    3569              :     __self_view __sv = __t;
    3570              :     return std::__str_rfind<value_type, size_type, traits_type, npos>
    3571              :         (data(), size(), __sv.data(), __pos, __sv.size());
    3572              : }
    3573              : 
    3574              : template<class _CharT, class _Traits, class _Allocator>
    3575              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3576              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3577              : basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
    3578              :                                                  size_type __pos) const _NOEXCEPT
    3579              : {
    3580              :     _LIBCPP_ASSERT(__s != nullptr, "string::rfind(): received nullptr");
    3581              :     return std::__str_rfind<value_type, size_type, traits_type, npos>
    3582              :         (data(), size(), __s, __pos, traits_type::length(__s));
    3583              : }
    3584              : 
    3585              : template<class _CharT, class _Traits, class _Allocator>
    3586              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3587              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3588              : basic_string<_CharT, _Traits, _Allocator>::rfind(value_type __c,
    3589              :                                                  size_type __pos) const _NOEXCEPT
    3590              : {
    3591              :     return std::__str_rfind<value_type, size_type, traits_type, npos>
    3592              :         (data(), size(), __c, __pos);
    3593              : }
    3594              : 
    3595              : // find_first_of
    3596              : 
    3597              : template<class _CharT, class _Traits, class _Allocator>
    3598              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3599              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3600              : basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
    3601              :                                                          size_type __pos,
    3602              :                                                          size_type __n) const _NOEXCEPT
    3603              : {
    3604              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_first_of(): received nullptr");
    3605              :     return std::__str_find_first_of<value_type, size_type, traits_type, npos>
    3606              :         (data(), size(), __s, __pos, __n);
    3607              : }
    3608              : 
    3609              : template<class _CharT, class _Traits, class _Allocator>
    3610              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3611              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3612         7781 : basic_string<_CharT, _Traits, _Allocator>::find_first_of(const basic_string& __str,
    3613              :                                                          size_type __pos) const _NOEXCEPT
    3614              : {
    3615         7781 :     return std::__str_find_first_of<value_type, size_type, traits_type, npos>
    3616         7781 :         (data(), size(), __str.data(), __pos, __str.size());
    3617              : }
    3618              : 
    3619              : template<class _CharT, class _Traits, class _Allocator>
    3620              : template <class _Tp>
    3621              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3622              : __enable_if_t
    3623              : <
    3624              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    3625              :     typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3626              : >
    3627              : basic_string<_CharT, _Traits, _Allocator>::find_first_of(const _Tp& __t,
    3628              :                                                 size_type __pos) const _NOEXCEPT
    3629              : {
    3630              :     __self_view __sv = __t;
    3631              :     return std::__str_find_first_of<value_type, size_type, traits_type, npos>
    3632              :         (data(), size(), __sv.data(), __pos, __sv.size());
    3633              : }
    3634              : 
    3635              : template<class _CharT, class _Traits, class _Allocator>
    3636              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3637              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3638         4515 : basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
    3639              :                                                          size_type __pos) const _NOEXCEPT
    3640              : {
    3641         4515 :     _LIBCPP_ASSERT(__s != nullptr, "string::find_first_of(): received nullptr");
    3642         4515 :     return std::__str_find_first_of<value_type, size_type, traits_type, npos>
    3643         4515 :         (data(), size(), __s, __pos, traits_type::length(__s));
    3644              : }
    3645              : 
    3646              : template<class _CharT, class _Traits, class _Allocator>
    3647              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3648              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3649              : basic_string<_CharT, _Traits, _Allocator>::find_first_of(value_type __c,
    3650              :                                                          size_type __pos) const _NOEXCEPT
    3651              : {
    3652              :     return find(__c, __pos);
    3653              : }
    3654              : 
    3655              : // find_last_of
    3656              : 
    3657              : template<class _CharT, class _Traits, class _Allocator>
    3658              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3659              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3660              : basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
    3661              :                                                         size_type __pos,
    3662              :                                                         size_type __n) const _NOEXCEPT
    3663              : {
    3664              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_last_of(): received nullptr");
    3665              :     return std::__str_find_last_of<value_type, size_type, traits_type, npos>
    3666              :         (data(), size(), __s, __pos, __n);
    3667              : }
    3668              : 
    3669              : template<class _CharT, class _Traits, class _Allocator>
    3670              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3671              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3672              : basic_string<_CharT, _Traits, _Allocator>::find_last_of(const basic_string& __str,
    3673              :                                                         size_type __pos) const _NOEXCEPT
    3674              : {
    3675              :     return std::__str_find_last_of<value_type, size_type, traits_type, npos>
    3676              :         (data(), size(), __str.data(), __pos, __str.size());
    3677              : }
    3678              : 
    3679              : template<class _CharT, class _Traits, class _Allocator>
    3680              : template <class _Tp>
    3681              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3682              : __enable_if_t
    3683              : <
    3684              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    3685              :     typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3686              : >
    3687              : basic_string<_CharT, _Traits, _Allocator>::find_last_of(const _Tp& __t,
    3688              :                                                 size_type __pos) const _NOEXCEPT
    3689              : {
    3690              :     __self_view __sv = __t;
    3691              :     return std::__str_find_last_of<value_type, size_type, traits_type, npos>
    3692              :         (data(), size(), __sv.data(), __pos, __sv.size());
    3693              : }
    3694              : 
    3695              : template<class _CharT, class _Traits, class _Allocator>
    3696              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3697              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3698              : basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
    3699              :                                                         size_type __pos) const _NOEXCEPT
    3700              : {
    3701              :     _LIBCPP_ASSERT(__s != nullptr, "string::find_last_of(): received nullptr");
    3702              :     return std::__str_find_last_of<value_type, size_type, traits_type, npos>
    3703              :         (data(), size(), __s, __pos, traits_type::length(__s));
    3704              : }
    3705              : 
    3706              : template<class _CharT, class _Traits, class _Allocator>
    3707              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3708              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3709              : basic_string<_CharT, _Traits, _Allocator>::find_last_of(value_type __c,
    3710              :                                                         size_type __pos) const _NOEXCEPT
    3711              : {
    3712              :     return rfind(__c, __pos);
    3713              : }
    3714              : 
    3715              : // find_first_not_of
    3716              : 
    3717              : template<class _CharT, class _Traits, class _Allocator>
    3718              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3719              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3720              : basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
    3721              :                                                              size_type __pos,
    3722              :                                                              size_type __n) const _NOEXCEPT
    3723              : {
    3724              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_first_not_of(): received nullptr");
    3725              :     return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
    3726              :         (data(), size(), __s, __pos, __n);
    3727              : }
    3728              : 
    3729              : template<class _CharT, class _Traits, class _Allocator>
    3730              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3731              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3732              : basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const basic_string& __str,
    3733              :                                                              size_type __pos) const _NOEXCEPT
    3734              : {
    3735              :     return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
    3736              :         (data(), size(), __str.data(), __pos, __str.size());
    3737              : }
    3738              : 
    3739              : template<class _CharT, class _Traits, class _Allocator>
    3740              : template <class _Tp>
    3741              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3742              : __enable_if_t
    3743              : <
    3744              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    3745              :     typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3746              : >
    3747              : basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const _Tp& __t,
    3748              :                                                 size_type __pos) const _NOEXCEPT
    3749              : {
    3750              :     __self_view __sv = __t;
    3751              :     return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
    3752              :         (data(), size(), __sv.data(), __pos, __sv.size());
    3753              : }
    3754              : 
    3755              : template<class _CharT, class _Traits, class _Allocator>
    3756              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3757              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3758         3209 : basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
    3759              :                                                              size_type __pos) const _NOEXCEPT
    3760              : {
    3761         3209 :     _LIBCPP_ASSERT(__s != nullptr, "string::find_first_not_of(): received nullptr");
    3762         3209 :     return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
    3763         3209 :         (data(), size(), __s, __pos, traits_type::length(__s));
    3764              : }
    3765              : 
    3766              : template<class _CharT, class _Traits, class _Allocator>
    3767              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3768              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3769              : basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(value_type __c,
    3770              :                                                              size_type __pos) const _NOEXCEPT
    3771              : {
    3772              :     return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
    3773              :         (data(), size(), __c, __pos);
    3774              : }
    3775              : 
    3776              : // find_last_not_of
    3777              : 
    3778              : template<class _CharT, class _Traits, class _Allocator>
    3779              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3780              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3781              : basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
    3782              :                                                             size_type __pos,
    3783              :                                                             size_type __n) const _NOEXCEPT
    3784              : {
    3785              :     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_last_not_of(): received nullptr");
    3786              :     return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
    3787              :         (data(), size(), __s, __pos, __n);
    3788              : }
    3789              : 
    3790              : template<class _CharT, class _Traits, class _Allocator>
    3791              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3792              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3793              : basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const basic_string& __str,
    3794              :                                                             size_type __pos) const _NOEXCEPT
    3795              : {
    3796              :     return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
    3797              :         (data(), size(), __str.data(), __pos, __str.size());
    3798              : }
    3799              : 
    3800              : template<class _CharT, class _Traits, class _Allocator>
    3801              : template <class _Tp>
    3802              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3803              : __enable_if_t
    3804              : <
    3805              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    3806              :     typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3807              : >
    3808              : basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const _Tp& __t,
    3809              :                                                 size_type __pos) const _NOEXCEPT
    3810              : {
    3811              :     __self_view __sv = __t;
    3812              :     return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
    3813              :         (data(), size(), __sv.data(), __pos, __sv.size());
    3814              : }
    3815              : 
    3816              : template<class _CharT, class _Traits, class _Allocator>
    3817              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3818              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3819          749 : basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
    3820              :                                                             size_type __pos) const _NOEXCEPT
    3821              : {
    3822          749 :     _LIBCPP_ASSERT(__s != nullptr, "string::find_last_not_of(): received nullptr");
    3823          749 :     return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
    3824          749 :         (data(), size(), __s, __pos, traits_type::length(__s));
    3825              : }
    3826              : 
    3827              : template<class _CharT, class _Traits, class _Allocator>
    3828              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3829              : typename basic_string<_CharT, _Traits, _Allocator>::size_type
    3830              : basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(value_type __c,
    3831              :                                                             size_type __pos) const _NOEXCEPT
    3832              : {
    3833              :     return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
    3834              :         (data(), size(), __c, __pos);
    3835              : }
    3836              : 
    3837              : // compare
    3838              : 
    3839              : template <class _CharT, class _Traits, class _Allocator>
    3840              : template <class _Tp>
    3841              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3842              : __enable_if_t
    3843              : <
    3844              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    3845              :     int
    3846              : >
    3847        13543 : basic_string<_CharT, _Traits, _Allocator>::compare(const _Tp& __t) const _NOEXCEPT
    3848              : {
    3849        13543 :     __self_view __sv = __t;
    3850        13543 :     size_t __lhs_sz = size();
    3851        13543 :     size_t __rhs_sz = __sv.size();
    3852        13543 :     int __result = traits_type::compare(data(), __sv.data(),
    3853        13543 :                                         std::min(__lhs_sz, __rhs_sz));
    3854        13543 :     if (__result != 0)
    3855        13461 :         return __result;
    3856           82 :     if (__lhs_sz < __rhs_sz)
    3857            2 :         return -1;
    3858           80 :     if (__lhs_sz > __rhs_sz)
    3859            8 :         return 1;
    3860           72 :     return 0;
    3861        13543 : }
    3862              : 
    3863              : template <class _CharT, class _Traits, class _Allocator>
    3864              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3865              : int
    3866        13543 : basic_string<_CharT, _Traits, _Allocator>::compare(const basic_string& __str) const _NOEXCEPT
    3867              : {
    3868        13543 :     return compare(__self_view(__str));
    3869              : }
    3870              : 
    3871              : template <class _CharT, class _Traits, class _Allocator>
    3872              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3873              : int
    3874              : basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
    3875              :                                                    size_type __n1,
    3876              :                                                    const value_type* __s,
    3877              :                                                    size_type __n2) const
    3878              : {
    3879              :     _LIBCPP_ASSERT(__n2 == 0 || __s != nullptr, "string::compare(): received nullptr");
    3880              :     size_type __sz = size();
    3881              :     if (__pos1 > __sz || __n2 == npos)
    3882              :         __throw_out_of_range();
    3883              :     size_type __rlen = std::min(__n1, __sz - __pos1);
    3884              :     int __r = traits_type::compare(data() + __pos1, __s, std::min(__rlen, __n2));
    3885              :     if (__r == 0)
    3886              :     {
    3887              :         if (__rlen < __n2)
    3888              :             __r = -1;
    3889              :         else if (__rlen > __n2)
    3890              :             __r = 1;
    3891              :     }
    3892              :     return __r;
    3893              : }
    3894              : 
    3895              : template <class _CharT, class _Traits, class _Allocator>
    3896              : template <class _Tp>
    3897              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3898              : __enable_if_t
    3899              : <
    3900              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
    3901              :     int
    3902              : >
    3903              : basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
    3904              :                                                    size_type __n1,
    3905              :                                                    const _Tp& __t) const
    3906              : {
    3907              :     __self_view __sv = __t;
    3908              :     return compare(__pos1, __n1, __sv.data(), __sv.size());
    3909              : }
    3910              : 
    3911              : template <class _CharT, class _Traits, class _Allocator>
    3912              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3913              : int
    3914              : basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
    3915              :                                                    size_type __n1,
    3916              :                                                    const basic_string& __str) const
    3917              : {
    3918              :     return compare(__pos1, __n1, __str.data(), __str.size());
    3919              : }
    3920              : 
    3921              : template <class _CharT, class _Traits, class _Allocator>
    3922              : template <class _Tp>
    3923              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3924              : __enable_if_t
    3925              : <
    3926              :     __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
    3927              :     && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
    3928              :     int
    3929              : >
    3930              : basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
    3931              :                                                    size_type __n1,
    3932              :                                                    const _Tp& __t,
    3933              :                                                    size_type __pos2,
    3934              :                                                    size_type __n2) const
    3935              : {
    3936              :     __self_view __sv = __t;
    3937              :     return __self_view(*this).substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
    3938              : }
    3939              : 
    3940              : template <class _CharT, class _Traits, class _Allocator>
    3941              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3942              : int
    3943              : basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
    3944              :                                                    size_type __n1,
    3945              :                                                    const basic_string& __str,
    3946              :                                                    size_type __pos2,
    3947              :                                                    size_type __n2) const
    3948              : {
    3949              :     return compare(__pos1, __n1, __self_view(__str), __pos2, __n2);
    3950              : }
    3951              : 
    3952              : template <class _CharT, class _Traits, class _Allocator>
    3953              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3954              : int
    3955              : basic_string<_CharT, _Traits, _Allocator>::compare(const value_type* __s) const _NOEXCEPT
    3956              : {
    3957              :     _LIBCPP_ASSERT(__s != nullptr, "string::compare(): received nullptr");
    3958              :     return compare(0, npos, __s, traits_type::length(__s));
    3959              : }
    3960              : 
    3961              : template <class _CharT, class _Traits, class _Allocator>
    3962              : _LIBCPP_CONSTEXPR_SINCE_CXX20
    3963              : int
    3964              : basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
    3965              :                                                    size_type __n1,
    3966              :                                                    const value_type* __s) const
    3967              : {
    3968              :     _LIBCPP_ASSERT(__s != nullptr, "string::compare(): received nullptr");
    3969              :     return compare(__pos1, __n1, __s, traits_type::length(__s));
    3970              : }
    3971              : 
    3972              : // __invariants
    3973              : 
    3974              : template<class _CharT, class _Traits, class _Allocator>
    3975              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3976              : bool
    3977              : basic_string<_CharT, _Traits, _Allocator>::__invariants() const
    3978              : {
    3979              :     if (size() > capacity())
    3980              :         return false;
    3981              :     if (capacity() < __min_cap - 1)
    3982              :         return false;
    3983              :     if (data() == nullptr)
    3984              :         return false;
    3985              :     if (data()[size()] != value_type())
    3986              :         return false;
    3987              :     return true;
    3988              : }
    3989              : 
    3990              : // __clear_and_shrink
    3991              : 
    3992              : template<class _CharT, class _Traits, class _Allocator>
    3993              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    3994              : void
    3995              : basic_string<_CharT, _Traits, _Allocator>::__clear_and_shrink() _NOEXCEPT
    3996              : {
    3997              :     clear();
    3998              :     if(__is_long())
    3999              :     {
    4000              :         __alloc_traits::deallocate(__alloc(), __get_long_pointer(), capacity() + 1);
    4001              :         __default_init();
    4002              :     }
    4003              : }
    4004              : 
    4005              : // operator==
    4006              : 
    4007              : template<class _CharT, class _Traits, class _Allocator>
    4008              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
    4009              : bool
    4010              : operator==(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4011              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4012              : {
    4013              : #if _LIBCPP_STD_VER > 17
    4014              :     return basic_string_view<_CharT, _Traits>(__lhs) == basic_string_view<_CharT, _Traits>(__rhs);
    4015              : #else
    4016              :     size_t __lhs_sz = __lhs.size();
    4017              :     return __lhs_sz == __rhs.size() && _Traits::compare(__lhs.data(),
    4018              :                                                         __rhs.data(),
    4019              :                                                         __lhs_sz) == 0;
    4020              : #endif
    4021              : }
    4022              : 
    4023              : template<class _Allocator>
    4024              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
    4025              : bool
    4026              : operator==(const basic_string<char, char_traits<char>, _Allocator>& __lhs,
    4027              :            const basic_string<char, char_traits<char>, _Allocator>& __rhs) _NOEXCEPT
    4028              : {
    4029              :     size_t __lhs_sz = __lhs.size();
    4030              :     if (__lhs_sz != __rhs.size())
    4031              :         return false;
    4032              :     const char* __lp = __lhs.data();
    4033              :     const char* __rp = __rhs.data();
    4034              :     if (__lhs.__is_long())
    4035              :         return char_traits<char>::compare(__lp, __rp, __lhs_sz) == 0;
    4036              :     for (; __lhs_sz != 0; --__lhs_sz, ++__lp, ++__rp)
    4037              :         if (*__lp != *__rp)
    4038              :             return false;
    4039              :     return true;
    4040              : }
    4041              : 
    4042              : #if _LIBCPP_STD_VER <= 17
    4043              : template<class _CharT, class _Traits, class _Allocator>
    4044              : inline _LIBCPP_HIDE_FROM_ABI
    4045              : bool
    4046              : operator==(const _CharT* __lhs,
    4047              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4048              : {
    4049              :     typedef basic_string<_CharT, _Traits, _Allocator> _String;
    4050              :     _LIBCPP_ASSERT(__lhs != nullptr, "operator==(char*, basic_string): received nullptr");
    4051              :     size_t __lhs_len = _Traits::length(__lhs);
    4052              :     if (__lhs_len != __rhs.size()) return false;
    4053              :     return __rhs.compare(0, _String::npos, __lhs, __lhs_len) == 0;
    4054              : }
    4055              : #endif // _LIBCPP_STD_VER <= 17
    4056              : 
    4057              : template<class _CharT, class _Traits, class _Allocator>
    4058              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
    4059              : bool
    4060           53 : operator==(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
    4061              :            const _CharT* __rhs) _NOEXCEPT
    4062              : {
    4063              : #if _LIBCPP_STD_VER > 17
    4064              :     return basic_string_view<_CharT, _Traits>(__lhs) == basic_string_view<_CharT, _Traits>(__rhs);
    4065              : #else
    4066              :     typedef basic_string<_CharT, _Traits, _Allocator> _String;
    4067           53 :     _LIBCPP_ASSERT(__rhs != nullptr, "operator==(basic_string, char*): received nullptr");
    4068           53 :     size_t __rhs_len = _Traits::length(__rhs);
    4069           53 :     if (__rhs_len != __lhs.size()) return false;
    4070            3 :     return __lhs.compare(0, _String::npos, __rhs, __rhs_len) == 0;
    4071              : #endif
    4072           53 : }
    4073              : 
    4074              : #if _LIBCPP_STD_VER > 17
    4075              : 
    4076              : template <class _CharT, class _Traits, class _Allocator>
    4077              : _LIBCPP_HIDE_FROM_ABI constexpr auto operator<=>(
    4078              :     const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4079              :     const basic_string<_CharT, _Traits, _Allocator>& __rhs) noexcept {
    4080              :     return basic_string_view<_CharT, _Traits>(__lhs) <=> basic_string_view<_CharT, _Traits>(__rhs);
    4081              : }
    4082              : 
    4083              : template <class _CharT, class _Traits, class _Allocator>
    4084              : _LIBCPP_HIDE_FROM_ABI constexpr auto
    4085              : operator<=>(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs) {
    4086              :     return basic_string_view<_CharT, _Traits>(__lhs) <=> basic_string_view<_CharT, _Traits>(__rhs);
    4087              : }
    4088              : 
    4089              : #else // _LIBCPP_STD_VER > 17
    4090              : 
    4091              : template<class _CharT, class _Traits, class _Allocator>
    4092              : inline _LIBCPP_HIDE_FROM_ABI
    4093              : bool
    4094              : operator!=(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
    4095              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4096              : {
    4097              :     return !(__lhs == __rhs);
    4098              : }
    4099              : 
    4100              : template<class _CharT, class _Traits, class _Allocator>
    4101              : inline _LIBCPP_HIDE_FROM_ABI
    4102              : bool
    4103              : operator!=(const _CharT* __lhs,
    4104              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4105              : {
    4106              :     return !(__lhs == __rhs);
    4107              : }
    4108              : 
    4109              : template<class _CharT, class _Traits, class _Allocator>
    4110              : inline _LIBCPP_HIDE_FROM_ABI
    4111              : bool
    4112              : operator!=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4113              :            const _CharT* __rhs) _NOEXCEPT
    4114              : {
    4115              :     return !(__lhs == __rhs);
    4116              : }
    4117              : 
    4118              : // operator<
    4119              : 
    4120              : template<class _CharT, class _Traits, class _Allocator>
    4121              : inline _LIBCPP_HIDE_FROM_ABI
    4122              : bool
    4123        13543 : operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4124              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4125              : {
    4126        13543 :     return __lhs.compare(__rhs) < 0;
    4127              : }
    4128              : 
    4129              : template<class _CharT, class _Traits, class _Allocator>
    4130              : inline _LIBCPP_HIDE_FROM_ABI
    4131              : bool
    4132              : operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4133              :            const _CharT* __rhs) _NOEXCEPT
    4134              : {
    4135              :     return __lhs.compare(__rhs) < 0;
    4136              : }
    4137              : 
    4138              : template<class _CharT, class _Traits, class _Allocator>
    4139              : inline _LIBCPP_HIDE_FROM_ABI
    4140              : bool
    4141              : operator< (const _CharT* __lhs,
    4142              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4143              : {
    4144              :     return __rhs.compare(__lhs) > 0;
    4145              : }
    4146              : 
    4147              : // operator>
    4148              : 
    4149              : template<class _CharT, class _Traits, class _Allocator>
    4150              : inline _LIBCPP_HIDE_FROM_ABI
    4151              : bool
    4152              : operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4153              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4154              : {
    4155              :     return __rhs < __lhs;
    4156              : }
    4157              : 
    4158              : template<class _CharT, class _Traits, class _Allocator>
    4159              : inline _LIBCPP_HIDE_FROM_ABI
    4160              : bool
    4161              : operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4162              :            const _CharT* __rhs) _NOEXCEPT
    4163              : {
    4164              :     return __rhs < __lhs;
    4165              : }
    4166              : 
    4167              : template<class _CharT, class _Traits, class _Allocator>
    4168              : inline _LIBCPP_HIDE_FROM_ABI
    4169              : bool
    4170              : operator> (const _CharT* __lhs,
    4171              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4172              : {
    4173              :     return __rhs < __lhs;
    4174              : }
    4175              : 
    4176              : // operator<=
    4177              : 
    4178              : template<class _CharT, class _Traits, class _Allocator>
    4179              : inline _LIBCPP_HIDE_FROM_ABI
    4180              : bool
    4181              : operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4182              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4183              : {
    4184              :     return !(__rhs < __lhs);
    4185              : }
    4186              : 
    4187              : template<class _CharT, class _Traits, class _Allocator>
    4188              : inline _LIBCPP_HIDE_FROM_ABI
    4189              : bool
    4190              : operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4191              :            const _CharT* __rhs) _NOEXCEPT
    4192              : {
    4193              :     return !(__rhs < __lhs);
    4194              : }
    4195              : 
    4196              : template<class _CharT, class _Traits, class _Allocator>
    4197              : inline _LIBCPP_HIDE_FROM_ABI
    4198              : bool
    4199              : operator<=(const _CharT* __lhs,
    4200              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4201              : {
    4202              :     return !(__rhs < __lhs);
    4203              : }
    4204              : 
    4205              : // operator>=
    4206              : 
    4207              : template<class _CharT, class _Traits, class _Allocator>
    4208              : inline _LIBCPP_HIDE_FROM_ABI
    4209              : bool
    4210              : operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4211              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4212              : {
    4213              :     return !(__lhs < __rhs);
    4214              : }
    4215              : 
    4216              : template<class _CharT, class _Traits, class _Allocator>
    4217              : inline _LIBCPP_HIDE_FROM_ABI
    4218              : bool
    4219              : operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4220              :            const _CharT* __rhs) _NOEXCEPT
    4221              : {
    4222              :     return !(__lhs < __rhs);
    4223              : }
    4224              : 
    4225              : template<class _CharT, class _Traits, class _Allocator>
    4226              : inline _LIBCPP_HIDE_FROM_ABI
    4227              : bool
    4228              : operator>=(const _CharT* __lhs,
    4229              :            const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
    4230              : {
    4231              :     return !(__lhs < __rhs);
    4232              : }
    4233              : #endif // _LIBCPP_STD_VER > 17
    4234              : 
    4235              : // operator +
    4236              : 
    4237              : template<class _CharT, class _Traits, class _Allocator>
    4238              : _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4239              : basic_string<_CharT, _Traits, _Allocator>
    4240              : operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4241              :           const basic_string<_CharT, _Traits, _Allocator>& __rhs)
    4242              : {
    4243              :     using _String = basic_string<_CharT, _Traits, _Allocator>;
    4244              :     auto __lhs_sz = __lhs.size();
    4245              :     auto __rhs_sz = __rhs.size();
    4246              :     _String __r(__uninitialized_size_tag(),
    4247              :                 __lhs_sz + __rhs_sz,
    4248              :                 _String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
    4249              :     auto __ptr = std::__to_address(__r.__get_pointer());
    4250              :     _Traits::copy(__ptr, __lhs.data(), __lhs_sz);
    4251              :     _Traits::copy(__ptr + __lhs_sz, __rhs.data(), __rhs_sz);
    4252              :     _Traits::assign(__ptr + __lhs_sz + __rhs_sz, 1, _CharT());
    4253              :     return __r;
    4254              : }
    4255              : 
    4256              : template<class _CharT, class _Traits, class _Allocator>
    4257              : _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20
    4258              : basic_string<_CharT, _Traits, _Allocator>
    4259              : operator+(const _CharT* __lhs , const basic_string<_CharT,_Traits,_Allocator>& __rhs)
    4260              : {
    4261              :     using _String = basic_string<_CharT, _Traits, _Allocator>;
    4262              :     auto __lhs_sz = _Traits::length(__lhs);
    4263              :     auto __rhs_sz = __rhs.size();
    4264              :     _String __r(__uninitialized_size_tag(),
    4265              :                 __lhs_sz + __rhs_sz,
    4266              :                 _String::__alloc_traits::select_on_container_copy_construction(__rhs.get_allocator()));
    4267              :     auto __ptr = std::__to_address(__r.__get_pointer());
    4268              :     _Traits::copy(__ptr, __lhs, __lhs_sz);
    4269              :     _Traits::copy(__ptr + __lhs_sz, __rhs.data(), __rhs_sz);
    4270              :     _Traits::assign(__ptr + __lhs_sz + __rhs_sz, 1, _CharT());
    4271              :     return __r;
    4272              : }
    4273              : 
    4274              : template<class _CharT, class _Traits, class _Allocator>
    4275              : _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4276              : basic_string<_CharT, _Traits, _Allocator>
    4277              : operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Allocator>& __rhs)
    4278              : {
    4279              :     using _String = basic_string<_CharT, _Traits, _Allocator>;
    4280              :     typename _String::size_type __rhs_sz = __rhs.size();
    4281              :     _String __r(__uninitialized_size_tag(),
    4282              :                 __rhs_sz + 1,
    4283              :                 _String::__alloc_traits::select_on_container_copy_construction(__rhs.get_allocator()));
    4284              :     auto __ptr = std::__to_address(__r.__get_pointer());
    4285              :     _Traits::assign(__ptr, 1, __lhs);
    4286              :     _Traits::copy(__ptr + 1, __rhs.data(), __rhs_sz);
    4287              :     _Traits::assign(__ptr + 1 + __rhs_sz, 1, _CharT());
    4288              :     return __r;
    4289              : }
    4290              : 
    4291              : template<class _CharT, class _Traits, class _Allocator>
    4292              : inline _LIBCPP_CONSTEXPR_SINCE_CXX20
    4293              : basic_string<_CharT, _Traits, _Allocator>
    4294              : operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs)
    4295              : {
    4296              :     using _String = basic_string<_CharT, _Traits, _Allocator>;
    4297              :     typename _String::size_type __lhs_sz = __lhs.size();
    4298              :     typename _String::size_type __rhs_sz = _Traits::length(__rhs);
    4299              :     _String __r(__uninitialized_size_tag(),
    4300              :                 __lhs_sz + __rhs_sz,
    4301              :                 _String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
    4302              :     auto __ptr = std::__to_address(__r.__get_pointer());
    4303              :     _Traits::copy(__ptr, __lhs.data(), __lhs_sz);
    4304              :     _Traits::copy(__ptr + __lhs_sz, __rhs, __rhs_sz);
    4305              :     _Traits::assign(__ptr + __lhs_sz + __rhs_sz, 1, _CharT());
    4306              :     return __r;
    4307              : }
    4308              : 
    4309              : template<class _CharT, class _Traits, class _Allocator>
    4310              : _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4311              : basic_string<_CharT, _Traits, _Allocator>
    4312              : operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, _CharT __rhs)
    4313              : {
    4314              :     using _String = basic_string<_CharT, _Traits, _Allocator>;
    4315              :     typename _String::size_type __lhs_sz = __lhs.size();
    4316              :     _String __r(__uninitialized_size_tag(),
    4317              :                 __lhs_sz + 1,
    4318              :                 _String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
    4319              :     auto __ptr = std::__to_address(__r.__get_pointer());
    4320              :     _Traits::copy(__ptr, __lhs.data(), __lhs_sz);
    4321              :     _Traits::assign(__ptr + __lhs_sz, 1, __rhs);
    4322              :     _Traits::assign(__ptr + 1 + __lhs_sz, 1, _CharT());
    4323              :     return __r;
    4324              : }
    4325              : 
    4326              : #ifndef _LIBCPP_CXX03_LANG
    4327              : 
    4328              : template<class _CharT, class _Traits, class _Allocator>
    4329              : inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4330              : basic_string<_CharT, _Traits, _Allocator>
    4331              : operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const basic_string<_CharT, _Traits, _Allocator>& __rhs)
    4332              : {
    4333              :     return std::move(__lhs.append(__rhs));
    4334              : }
    4335              : 
    4336              : template<class _CharT, class _Traits, class _Allocator>
    4337              : inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4338              : basic_string<_CharT, _Traits, _Allocator>
    4339              : operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
    4340              : {
    4341              :     return std::move(__rhs.insert(0, __lhs));
    4342              : }
    4343              : 
    4344              : template<class _CharT, class _Traits, class _Allocator>
    4345              : inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4346              : basic_string<_CharT, _Traits, _Allocator>
    4347              : operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
    4348              : {
    4349              :     return std::move(__lhs.append(__rhs));
    4350              : }
    4351              : 
    4352              : template<class _CharT, class _Traits, class _Allocator>
    4353              : inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4354              : basic_string<_CharT, _Traits, _Allocator>
    4355              : operator+(const _CharT* __lhs , basic_string<_CharT,_Traits,_Allocator>&& __rhs)
    4356              : {
    4357              :     return std::move(__rhs.insert(0, __lhs));
    4358              : }
    4359              : 
    4360              : template<class _CharT, class _Traits, class _Allocator>
    4361              : inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4362              : basic_string<_CharT, _Traits, _Allocator>
    4363              : operator+(_CharT __lhs, basic_string<_CharT,_Traits,_Allocator>&& __rhs)
    4364              : {
    4365              :     __rhs.insert(__rhs.begin(), __lhs);
    4366              :     return std::move(__rhs);
    4367              : }
    4368              : 
    4369              : template<class _CharT, class _Traits, class _Allocator>
    4370              : inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4371              : basic_string<_CharT, _Traits, _Allocator>
    4372              : operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const _CharT* __rhs)
    4373              : {
    4374              :     return std::move(__lhs.append(__rhs));
    4375              : }
    4376              : 
    4377              : template<class _CharT, class _Traits, class _Allocator>
    4378              : inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4379              : basic_string<_CharT, _Traits, _Allocator>
    4380              : operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, _CharT __rhs)
    4381              : {
    4382              :     __lhs.push_back(__rhs);
    4383              :     return std::move(__lhs);
    4384              : }
    4385              : 
    4386              : #endif // _LIBCPP_CXX03_LANG
    4387              : 
    4388              : // swap
    4389              : 
    4390              : template<class _CharT, class _Traits, class _Allocator>
    4391              : inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4392              : void
    4393              : swap(basic_string<_CharT, _Traits, _Allocator>& __lhs,
    4394              :      basic_string<_CharT, _Traits, _Allocator>& __rhs)
    4395              :      _NOEXCEPT_(_NOEXCEPT_(__lhs.swap(__rhs)))
    4396              : {
    4397              :     __lhs.swap(__rhs);
    4398              : }
    4399              : 
    4400              : _LIBCPP_FUNC_VIS int                stoi  (const string& __str, size_t* __idx = nullptr, int __base = 10);
    4401              : _LIBCPP_FUNC_VIS long               stol  (const string& __str, size_t* __idx = nullptr, int __base = 10);
    4402              : _LIBCPP_FUNC_VIS unsigned long      stoul (const string& __str, size_t* __idx = nullptr, int __base = 10);
    4403              : _LIBCPP_FUNC_VIS long long          stoll (const string& __str, size_t* __idx = nullptr, int __base = 10);
    4404              : _LIBCPP_FUNC_VIS unsigned long long stoull(const string& __str, size_t* __idx = nullptr, int __base = 10);
    4405              : 
    4406              : _LIBCPP_FUNC_VIS float       stof (const string& __str, size_t* __idx = nullptr);
    4407              : _LIBCPP_FUNC_VIS double      stod (const string& __str, size_t* __idx = nullptr);
    4408              : _LIBCPP_FUNC_VIS long double stold(const string& __str, size_t* __idx = nullptr);
    4409              : 
    4410              : _LIBCPP_FUNC_VIS string to_string(int __val);
    4411              : _LIBCPP_FUNC_VIS string to_string(unsigned __val);
    4412              : _LIBCPP_FUNC_VIS string to_string(long __val);
    4413              : _LIBCPP_FUNC_VIS string to_string(unsigned long __val);
    4414              : _LIBCPP_FUNC_VIS string to_string(long long __val);
    4415              : _LIBCPP_FUNC_VIS string to_string(unsigned long long __val);
    4416              : _LIBCPP_FUNC_VIS string to_string(float __val);
    4417              : _LIBCPP_FUNC_VIS string to_string(double __val);
    4418              : _LIBCPP_FUNC_VIS string to_string(long double __val);
    4419              : 
    4420              : #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
    4421              : _LIBCPP_FUNC_VIS int                stoi  (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
    4422              : _LIBCPP_FUNC_VIS long               stol  (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
    4423              : _LIBCPP_FUNC_VIS unsigned long      stoul (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
    4424              : _LIBCPP_FUNC_VIS long long          stoll (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
    4425              : _LIBCPP_FUNC_VIS unsigned long long stoull(const wstring& __str, size_t* __idx = nullptr, int __base = 10);
    4426              : 
    4427              : _LIBCPP_FUNC_VIS float       stof (const wstring& __str, size_t* __idx = nullptr);
    4428              : _LIBCPP_FUNC_VIS double      stod (const wstring& __str, size_t* __idx = nullptr);
    4429              : _LIBCPP_FUNC_VIS long double stold(const wstring& __str, size_t* __idx = nullptr);
    4430              : 
    4431              : _LIBCPP_FUNC_VIS wstring to_wstring(int __val);
    4432              : _LIBCPP_FUNC_VIS wstring to_wstring(unsigned __val);
    4433              : _LIBCPP_FUNC_VIS wstring to_wstring(long __val);
    4434              : _LIBCPP_FUNC_VIS wstring to_wstring(unsigned long __val);
    4435              : _LIBCPP_FUNC_VIS wstring to_wstring(long long __val);
    4436              : _LIBCPP_FUNC_VIS wstring to_wstring(unsigned long long __val);
    4437              : _LIBCPP_FUNC_VIS wstring to_wstring(float __val);
    4438              : _LIBCPP_FUNC_VIS wstring to_wstring(double __val);
    4439              : _LIBCPP_FUNC_VIS wstring to_wstring(long double __val);
    4440              : #endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
    4441              : 
    4442              : template<class _CharT, class _Traits, class _Allocator>
    4443              : _LIBCPP_TEMPLATE_DATA_VIS
    4444              : const typename basic_string<_CharT, _Traits, _Allocator>::size_type
    4445              :                basic_string<_CharT, _Traits, _Allocator>::npos;
    4446              : 
    4447              : template <class _CharT, class _Allocator>
    4448              : struct __string_hash : public __unary_function<basic_string<_CharT, char_traits<_CharT>, _Allocator>, size_t>
    4449              : {
    4450              :     size_t
    4451              :     operator()(const basic_string<_CharT, char_traits<_CharT>, _Allocator>& __val) const _NOEXCEPT
    4452              :     { return std::__do_string_hash(__val.data(), __val.data() + __val.size()); }
    4453              : };
    4454              : 
    4455              : template <class _Allocator>
    4456              : struct hash<basic_string<char, char_traits<char>, _Allocator> > : __string_hash<char, _Allocator> {};
    4457              : 
    4458              : #ifndef _LIBCPP_HAS_NO_CHAR8_T
    4459              : template <class _Allocator>
    4460              : struct hash<basic_string<char8_t, char_traits<char8_t>, _Allocator> > : __string_hash<char8_t, _Allocator> {};
    4461              : #endif
    4462              : 
    4463              : template <class _Allocator>
    4464              : struct hash<basic_string<char16_t, char_traits<char16_t>, _Allocator> > : __string_hash<char16_t, _Allocator> {};
    4465              : 
    4466              : template <class _Allocator>
    4467              : struct hash<basic_string<char32_t, char_traits<char32_t>, _Allocator> > : __string_hash<char32_t, _Allocator> {};
    4468              : 
    4469              : #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
    4470              : template <class _Allocator>
    4471              : struct hash<basic_string<wchar_t, char_traits<wchar_t>, _Allocator> > : __string_hash<wchar_t, _Allocator> {};
    4472              : #endif
    4473              : 
    4474              : template<class _CharT, class _Traits, class _Allocator>
    4475              : _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
    4476              : operator<<(basic_ostream<_CharT, _Traits>& __os,
    4477              :            const basic_string<_CharT, _Traits, _Allocator>& __str);
    4478              : 
    4479              : template<class _CharT, class _Traits, class _Allocator>
    4480              : _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
    4481              : operator>>(basic_istream<_CharT, _Traits>& __is,
    4482              :            basic_string<_CharT, _Traits, _Allocator>& __str);
    4483              : 
    4484              : template<class _CharT, class _Traits, class _Allocator>
    4485              : _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
    4486              : getline(basic_istream<_CharT, _Traits>& __is,
    4487              :         basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
    4488              : 
    4489              : template<class _CharT, class _Traits, class _Allocator>
    4490              : inline _LIBCPP_HIDE_FROM_ABI
    4491              : basic_istream<_CharT, _Traits>&
    4492              : getline(basic_istream<_CharT, _Traits>& __is,
    4493              :         basic_string<_CharT, _Traits, _Allocator>& __str);
    4494              : 
    4495              : template<class _CharT, class _Traits, class _Allocator>
    4496              : inline _LIBCPP_HIDE_FROM_ABI
    4497              : basic_istream<_CharT, _Traits>&
    4498              : getline(basic_istream<_CharT, _Traits>&& __is,
    4499              :         basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
    4500              : 
    4501              : template<class _CharT, class _Traits, class _Allocator>
    4502              : inline _LIBCPP_HIDE_FROM_ABI
    4503              : basic_istream<_CharT, _Traits>&
    4504              : getline(basic_istream<_CharT, _Traits>&& __is,
    4505              :         basic_string<_CharT, _Traits, _Allocator>& __str);
    4506              : 
    4507              : #if _LIBCPP_STD_VER > 17
    4508              : template <class _CharT, class _Traits, class _Allocator, class _Up>
    4509              : inline _LIBCPP_HIDE_FROM_ABI
    4510              :     typename basic_string<_CharT, _Traits, _Allocator>::size_type
    4511              :     erase(basic_string<_CharT, _Traits, _Allocator>& __str, const _Up& __v) {
    4512              :   auto __old_size = __str.size();
    4513              :   __str.erase(std::remove(__str.begin(), __str.end(), __v), __str.end());
    4514              :   return __old_size - __str.size();
    4515              : }
    4516              : 
    4517              : template <class _CharT, class _Traits, class _Allocator, class _Predicate>
    4518              : inline _LIBCPP_HIDE_FROM_ABI
    4519              :     typename basic_string<_CharT, _Traits, _Allocator>::size_type
    4520              :     erase_if(basic_string<_CharT, _Traits, _Allocator>& __str,
    4521              :              _Predicate __pred) {
    4522              :   auto __old_size = __str.size();
    4523              :   __str.erase(std::remove_if(__str.begin(), __str.end(), __pred),
    4524              :               __str.end());
    4525              :   return __old_size - __str.size();
    4526              : }
    4527              : #endif
    4528              : 
    4529              : #ifdef _LIBCPP_ENABLE_DEBUG_MODE
    4530              : 
    4531              : template<class _CharT, class _Traits, class _Allocator>
    4532              : bool
    4533              : basic_string<_CharT, _Traits, _Allocator>::__dereferenceable(const const_iterator* __i) const
    4534              : {
    4535              :     return data() <= std::__to_address(__i->base()) &&
    4536              :            std::__to_address(__i->base()) < data() + size();
    4537              : }
    4538              : 
    4539              : template<class _CharT, class _Traits, class _Allocator>
    4540              : bool
    4541              : basic_string<_CharT, _Traits, _Allocator>::__decrementable(const const_iterator* __i) const
    4542              : {
    4543              :     return data() < std::__to_address(__i->base()) &&
    4544              :            std::__to_address(__i->base()) <= data() + size();
    4545              : }
    4546              : 
    4547              : template<class _CharT, class _Traits, class _Allocator>
    4548              : bool
    4549              : basic_string<_CharT, _Traits, _Allocator>::__addable(const const_iterator* __i, ptrdiff_t __n) const
    4550              : {
    4551              :     const value_type* __p = std::__to_address(__i->base()) + __n;
    4552              :     return data() <= __p && __p <= data() + size();
    4553              : }
    4554              : 
    4555              : template<class _CharT, class _Traits, class _Allocator>
    4556              : bool
    4557              : basic_string<_CharT, _Traits, _Allocator>::__subscriptable(const const_iterator* __i, ptrdiff_t __n) const
    4558              : {
    4559              :     const value_type* __p = std::__to_address(__i->base()) + __n;
    4560              :     return data() <= __p && __p < data() + size();
    4561              : }
    4562              : 
    4563              : #endif // _LIBCPP_ENABLE_DEBUG_MODE
    4564              : 
    4565              : #if _LIBCPP_STD_VER > 11
    4566              : // Literal suffixes for basic_string [basic.string.literals]
    4567              : inline namespace literals
    4568              : {
    4569              :   inline namespace string_literals
    4570              :   {
    4571              :     inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4572              :     basic_string<char> operator "" s( const char *__str, size_t __len )
    4573              :     {
    4574              :         return basic_string<char> (__str, __len);
    4575              :     }
    4576              : 
    4577              : #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
    4578              :     inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4579              :     basic_string<wchar_t> operator "" s( const wchar_t *__str, size_t __len )
    4580              :     {
    4581              :         return basic_string<wchar_t> (__str, __len);
    4582              :     }
    4583              : #endif
    4584              : 
    4585              : #ifndef _LIBCPP_HAS_NO_CHAR8_T
    4586              :     inline _LIBCPP_HIDE_FROM_ABI constexpr
    4587              :     basic_string<char8_t> operator "" s(const char8_t *__str, size_t __len)
    4588              :     {
    4589              :         return basic_string<char8_t> (__str, __len);
    4590              :     }
    4591              : #endif
    4592              : 
    4593              :     inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4594              :     basic_string<char16_t> operator "" s( const char16_t *__str, size_t __len )
    4595              :     {
    4596              :         return basic_string<char16_t> (__str, __len);
    4597              :     }
    4598              : 
    4599              :     inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
    4600              :     basic_string<char32_t> operator "" s( const char32_t *__str, size_t __len )
    4601              :     {
    4602              :         return basic_string<char32_t> (__str, __len);
    4603              :     }
    4604              :   } // namespace string_literals
    4605              : } // namespace literals
    4606              : 
    4607              : #if _LIBCPP_STD_VER > 17
    4608              : template <>
    4609              : inline constexpr bool __format::__enable_insertable<std::basic_string<char>> = true;
    4610              : #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
    4611              : template <>
    4612              : inline constexpr bool __format::__enable_insertable<std::basic_string<wchar_t>> = true;
    4613              : #endif
    4614              : #endif
    4615              : 
    4616              : #endif
    4617              : 
    4618              : _LIBCPP_END_NAMESPACE_STD
    4619              : 
    4620              : _LIBCPP_POP_MACROS
    4621              : 
    4622              : #if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
    4623              : #  include <algorithm>
    4624              : #  include <concepts>
    4625              : #  include <functional>
    4626              : #  include <iterator>
    4627              : #  include <new>
    4628              : #  include <typeinfo>
    4629              : #  include <utility>
    4630              : #  include <vector>
    4631              : #endif
    4632              : 
    4633              : #endif // _LIBCPP_STRING
        

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