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  1. // Components for manipulating sequences of characters -*- C++ -*-
  2.  
  3. // Copyright (C) 1997-2013 Free Software Foundation, Inc.
  4. //
  5. // This file is part of the GNU ISO C++ Library.  This library is free
  6. // software; you can redistribute it and/or modify it under the
  7. // terms of the GNU General Public License as published by the
  8. // Free Software Foundation; either version 3, or (at your option)
  9. // any later version.
  10.  
  11. // This library is distributed in the hope that it will be useful,
  12. // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13. // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14. // GNU General Public License for more details.
  15.  
  16. // Under Section 7 of GPL version 3, you are granted additional
  17. // permissions described in the GCC Runtime Library Exception, version
  18. // 3.1, as published by the Free Software Foundation.
  19.  
  20. // You should have received a copy of the GNU General Public License and
  21. // a copy of the GCC Runtime Library Exception along with this program;
  22. // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23. // <http://www.gnu.org/licenses/>.
  24.  
  25. /** @file bits/basic_string.h
  26.  *  This is an internal header file, included by other library headers.
  27.  *  Do not attempt to use it directly. @headername{string}
  28.  */
  29.  
  30. //
  31. // ISO C++ 14882: 21 Strings library
  32. //
  33.  
  34. #ifndef _BASIC_STRING_H
  35. #define _BASIC_STRING_H 1
  36.  
  37. #pragma GCC system_header
  38.  
  39. #include <ext/atomicity.h>
  40. #include <debug/debug.h>
  41. #if __cplusplus >= 201103L
  42. #include <initializer_list>
  43. #endif
  44.  
  45. namespace std _GLIBCXX_VISIBILITY(default)
  46. {
  47. _GLIBCXX_BEGIN_NAMESPACE_VERSION
  48.  
  49.   /**
  50.    *  @class basic_string basic_string.h <string>
  51.    *  @brief  Managing sequences of characters and character-like objects.
  52.    *
  53.    *  @ingroup strings
  54.    *  @ingroup sequences
  55.    *
  56.    *  @tparam _CharT  Type of character
  57.    *  @tparam _Traits  Traits for character type, defaults to
  58.    *                   char_traits<_CharT>.
  59.    *  @tparam _Alloc  Allocator type, defaults to allocator<_CharT>.
  60.    *
  61.    *  Meets the requirements of a <a href="tables.html#65">container</a>, a
  62.    *  <a href="tables.html#66">reversible container</a>, and a
  63.    *  <a href="tables.html#67">sequence</a>.  Of the
  64.    *  <a href="tables.html#68">optional sequence requirements</a>, only
  65.    *  @c push_back, @c at, and @c %array access are supported.
  66.    *
  67.    *  @doctodo
  68.    *
  69.    *
  70.    *  Documentation?  What's that?
  71.    *  Nathan Myers <ncm@cantrip.org>.
  72.    *
  73.    *  A string looks like this:
  74.    *
  75.    *  @code
  76.    *                                        [_Rep]
  77.    *                                        _M_length
  78.    *   [basic_string<char_type>]            _M_capacity
  79.    *   _M_dataplus                          _M_refcount
  80.    *   _M_p ---------------->               unnamed array of char_type
  81.    *  @endcode
  82.    *
  83.    *  Where the _M_p points to the first character in the string, and
  84.    *  you cast it to a pointer-to-_Rep and subtract 1 to get a
  85.    *  pointer to the header.
  86.    *
  87.    *  This approach has the enormous advantage that a string object
  88.    *  requires only one allocation.  All the ugliness is confined
  89.    *  within a single %pair of inline functions, which each compile to
  90.    *  a single @a add instruction: _Rep::_M_data(), and
  91.    *  string::_M_rep(); and the allocation function which gets a
  92.    *  block of raw bytes and with room enough and constructs a _Rep
  93.    *  object at the front.
  94.    *
  95.    *  The reason you want _M_data pointing to the character %array and
  96.    *  not the _Rep is so that the debugger can see the string
  97.    *  contents. (Probably we should add a non-inline member to get
  98.    *  the _Rep for the debugger to use, so users can check the actual
  99.    *  string length.)
  100.    *
  101.    *  Note that the _Rep object is a POD so that you can have a
  102.    *  static <em>empty string</em> _Rep object already @a constructed before
  103.    *  static constructors have run.  The reference-count encoding is
  104.    *  chosen so that a 0 indicates one reference, so you never try to
  105.    *  destroy the empty-string _Rep object.
  106.    *
  107.    *  All but the last paragraph is considered pretty conventional
  108.    *  for a C++ string implementation.
  109.   */
  110.   // 21.3  Template class basic_string
  111.   template<typename _CharT, typename _Traits, typename _Alloc>
  112.     class basic_string
  113.     {
  114.       typedef typename _Alloc::template rebind<_CharT>::other _CharT_alloc_type;
  115.  
  116.       // Types:
  117.     public:
  118.       typedef _Traits                                       traits_type;
  119.       typedef typename _Traits::char_type                   value_type;
  120.       typedef _Alloc                                        allocator_type;
  121.       typedef typename _CharT_alloc_type::size_type         size_type;
  122.       typedef typename _CharT_alloc_type::difference_type   difference_type;
  123.       typedef typename _CharT_alloc_type::reference         reference;
  124.       typedef typename _CharT_alloc_type::const_reference   const_reference;
  125.       typedef typename _CharT_alloc_type::pointer           pointer;
  126.       typedef typename _CharT_alloc_type::const_pointer     const_pointer;
  127.       typedef __gnu_cxx::__normal_iterator<pointer, basic_string>  iterator;
  128.       typedef __gnu_cxx::__normal_iterator<const_pointer, basic_string>
  129.                                                             const_iterator;
  130.       typedef std::reverse_iterator<const_iterator>     const_reverse_iterator;
  131.       typedef std::reverse_iterator<iterator>               reverse_iterator;
  132.  
  133.     private:
  134.       // _Rep: string representation
  135.       //   Invariants:
  136.       //   1. String really contains _M_length + 1 characters: due to 21.3.4
  137.       //      must be kept null-terminated.
  138.       //   2. _M_capacity >= _M_length
  139.       //      Allocated memory is always (_M_capacity + 1) * sizeof(_CharT).
  140.       //   3. _M_refcount has three states:
  141.       //      -1: leaked, one reference, no ref-copies allowed, non-const.
  142.       //       0: one reference, non-const.
  143.       //     n>0: n + 1 references, operations require a lock, const.
  144.       //   4. All fields==0 is an empty string, given the extra storage
  145.       //      beyond-the-end for a null terminator; thus, the shared
  146.       //      empty string representation needs no constructor.
  147.  
  148.       struct _Rep_base
  149.       {
  150.         size_type               _M_length;
  151.         size_type               _M_capacity;
  152.         _Atomic_word            _M_refcount;
  153.       };
  154.  
  155.       struct _Rep : _Rep_base
  156.       {
  157.         // Types:
  158.         typedef typename _Alloc::template rebind<char>::other _Raw_bytes_alloc;
  159.  
  160.         // (Public) Data members:
  161.  
  162.         // The maximum number of individual char_type elements of an
  163.         // individual string is determined by _S_max_size. This is the
  164.         // value that will be returned by max_size().  (Whereas npos
  165.         // is the maximum number of bytes the allocator can allocate.)
  166.         // If one was to divvy up the theoretical largest size string,
  167.         // with a terminating character and m _CharT elements, it'd
  168.         // look like this:
  169.         // npos = sizeof(_Rep) + (m * sizeof(_CharT)) + sizeof(_CharT)
  170.         // Solving for m:
  171.         // m = ((npos - sizeof(_Rep))/sizeof(CharT)) - 1
  172.         // In addition, this implementation quarters this amount.
  173.         static const size_type  _S_max_size;
  174.         static const _CharT     _S_terminal;
  175.  
  176.         // The following storage is init'd to 0 by the linker, resulting
  177.         // (carefully) in an empty string with one reference.
  178.         static size_type _S_empty_rep_storage[];
  179.  
  180.         static _Rep&
  181.         _S_empty_rep()
  182.         {
  183.           // NB: Mild hack to avoid strict-aliasing warnings.  Note that
  184.           // _S_empty_rep_storage is never modified and the punning should
  185.           // be reasonably safe in this case.
  186.           void* __p = reinterpret_cast<void*>(&_S_empty_rep_storage);
  187.           return *reinterpret_cast<_Rep*>(__p);
  188.         }
  189.  
  190.         bool
  191.         _M_is_leaked() const
  192.         { return this->_M_refcount < 0; }
  193.  
  194.         bool
  195.         _M_is_shared() const
  196.         { return this->_M_refcount > 0; }
  197.  
  198.         void
  199.         _M_set_leaked()
  200.         { this->_M_refcount = -1; }
  201.  
  202.         void
  203.         _M_set_sharable()
  204.         { this->_M_refcount = 0; }
  205.  
  206.         void
  207.         _M_set_length_and_sharable(size_type __n)
  208.         {
  209. #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
  210.           if (__builtin_expect(this != &_S_empty_rep(), false))
  211. #endif
  212.             {
  213.               this->_M_set_sharable();  // One reference.
  214.               this->_M_length = __n;
  215.               traits_type::assign(this->_M_refdata()[__n], _S_terminal);
  216.               // grrr. (per 21.3.4)
  217.               // You cannot leave those LWG people alone for a second.
  218.             }
  219.         }
  220.  
  221.         _CharT*
  222.         _M_refdata() throw()
  223.         { return reinterpret_cast<_CharT*>(this + 1); }
  224.  
  225.         _CharT*
  226.         _M_grab(const _Alloc& __alloc1, const _Alloc& __alloc2)
  227.         {
  228.           return (!_M_is_leaked() && __alloc1 == __alloc2)
  229.                   ? _M_refcopy() : _M_clone(__alloc1);
  230.         }
  231.  
  232.         // Create & Destroy
  233.         static _Rep*
  234.         _S_create(size_type, size_type, const _Alloc&);
  235.  
  236.         void
  237.         _M_dispose(const _Alloc& __a)
  238.         {
  239. #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
  240.           if (__builtin_expect(this != &_S_empty_rep(), false))
  241. #endif
  242.             {
  243.               // Be race-detector-friendly.  For more info see bits/c++config.
  244.               _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&this->_M_refcount);
  245.               if (__gnu_cxx::__exchange_and_add_dispatch(&this->_M_refcount,
  246.                                                          -1) <= 0)
  247.                 {
  248.                   _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&this->_M_refcount);
  249.                   _M_destroy(__a);
  250.                 }
  251.             }
  252.         }  // XXX MT
  253.  
  254.         void
  255.         _M_destroy(const _Alloc&) throw();
  256.  
  257.         _CharT*
  258.         _M_refcopy() throw()
  259.         {
  260. #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
  261.           if (__builtin_expect(this != &_S_empty_rep(), false))
  262. #endif
  263.             __gnu_cxx::__atomic_add_dispatch(&this->_M_refcount, 1);
  264.           return _M_refdata();
  265.         }  // XXX MT
  266.  
  267.         _CharT*
  268.         _M_clone(const _Alloc&, size_type __res = 0);
  269.       };
  270.  
  271.       // Use empty-base optimization: http://www.cantrip.org/emptyopt.html
  272.       struct _Alloc_hider : _Alloc
  273.       {
  274.         _Alloc_hider(_CharT* __dat, const _Alloc& __a)
  275.         : _Alloc(__a), _M_p(__dat) { }
  276.  
  277.         _CharT* _M_p; // The actual data.
  278.       };
  279.  
  280.     public:
  281.       // Data Members (public):
  282.       // NB: This is an unsigned type, and thus represents the maximum
  283.       // size that the allocator can hold.
  284.       ///  Value returned by various member functions when they fail.
  285.       static const size_type    npos = static_cast<size_type>(-1);
  286.  
  287.     private:
  288.       // Data Members (private):
  289.       mutable _Alloc_hider      _M_dataplus;
  290.  
  291.       _CharT*
  292.       _M_data() const
  293.       { return  _M_dataplus._M_p; }
  294.  
  295.       _CharT*
  296.       _M_data(_CharT* __p)
  297.       { return (_M_dataplus._M_p = __p); }
  298.  
  299.       _Rep*
  300.       _M_rep() const
  301.       { return &((reinterpret_cast<_Rep*> (_M_data()))[-1]); }
  302.  
  303.       // For the internal use we have functions similar to `begin'/`end'
  304.       // but they do not call _M_leak.
  305.       iterator
  306.       _M_ibegin() const
  307.       { return iterator(_M_data()); }
  308.  
  309.       iterator
  310.       _M_iend() const
  311.       { return iterator(_M_data() + this->size()); }
  312.  
  313.       void
  314.       _M_leak()    // for use in begin() & non-const op[]
  315.       {
  316.         if (!_M_rep()->_M_is_leaked())
  317.           _M_leak_hard();
  318.       }
  319.  
  320.       size_type
  321.       _M_check(size_type __pos, const char* __s) const
  322.       {
  323.         if (__pos > this->size())
  324.           __throw_out_of_range(__N(__s));
  325.         return __pos;
  326.       }
  327.  
  328.       void
  329.       _M_check_length(size_type __n1, size_type __n2, const char* __s) const
  330.       {
  331.         if (this->max_size() - (this->size() - __n1) < __n2)
  332.           __throw_length_error(__N(__s));
  333.       }
  334.  
  335.       // NB: _M_limit doesn't check for a bad __pos value.
  336.       size_type
  337.       _M_limit(size_type __pos, size_type __off) const
  338.       {
  339.         const bool __testoff =  __off < this->size() - __pos;
  340.         return __testoff ? __off : this->size() - __pos;
  341.       }
  342.  
  343.       // True if _Rep and source do not overlap.
  344.       bool
  345.       _M_disjunct(const _CharT* __s) const
  346.       {
  347.         return (less<const _CharT*>()(__s, _M_data())
  348.                 || less<const _CharT*>()(_M_data() + this->size(), __s));
  349.       }
  350.  
  351.       // When __n = 1 way faster than the general multichar
  352.       // traits_type::copy/move/assign.
  353.       static void
  354.       _M_copy(_CharT* __d, const _CharT* __s, size_type __n)
  355.       {
  356.         if (__n == 1)
  357.           traits_type::assign(*__d, *__s);
  358.         else
  359.           traits_type::copy(__d, __s, __n);
  360.       }
  361.  
  362.       static void
  363.       _M_move(_CharT* __d, const _CharT* __s, size_type __n)
  364.       {
  365.         if (__n == 1)
  366.           traits_type::assign(*__d, *__s);
  367.         else
  368.           traits_type::move(__d, __s, __n);      
  369.       }
  370.  
  371.       static void
  372.       _M_assign(_CharT* __d, size_type __n, _CharT __c)
  373.       {
  374.         if (__n == 1)
  375.           traits_type::assign(*__d, __c);
  376.         else
  377.           traits_type::assign(__d, __n, __c);    
  378.       }
  379.  
  380.       // _S_copy_chars is a separate template to permit specialization
  381.       // to optimize for the common case of pointers as iterators.
  382.       template<class _Iterator>
  383.         static void
  384.         _S_copy_chars(_CharT* __p, _Iterator __k1, _Iterator __k2)
  385.         {
  386.           for (; __k1 != __k2; ++__k1, ++__p)
  387.             traits_type::assign(*__p, *__k1); // These types are off.
  388.         }
  389.  
  390.       static void
  391.       _S_copy_chars(_CharT* __p, iterator __k1, iterator __k2)
  392.       { _S_copy_chars(__p, __k1.base(), __k2.base()); }
  393.  
  394.       static void
  395.       _S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2)
  396.       { _S_copy_chars(__p, __k1.base(), __k2.base()); }
  397.  
  398.       static void
  399.       _S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2)
  400.       { _M_copy(__p, __k1, __k2 - __k1); }
  401.  
  402.       static void
  403.       _S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
  404.       { _M_copy(__p, __k1, __k2 - __k1); }
  405.  
  406.       static int
  407.       _S_compare(size_type __n1, size_type __n2)
  408.       {
  409.         const difference_type __d = difference_type(__n1 - __n2);
  410.  
  411.         if (__d > __gnu_cxx::__numeric_traits<int>::__max)
  412.           return __gnu_cxx::__numeric_traits<int>::__max;
  413.         else if (__d < __gnu_cxx::__numeric_traits<int>::__min)
  414.           return __gnu_cxx::__numeric_traits<int>::__min;
  415.         else
  416.           return int(__d);
  417.       }
  418.  
  419.       void
  420.       _M_mutate(size_type __pos, size_type __len1, size_type __len2);
  421.  
  422.       void
  423.       _M_leak_hard();
  424.  
  425.       static _Rep&
  426.       _S_empty_rep()
  427.       { return _Rep::_S_empty_rep(); }
  428.  
  429.     public:
  430.       // Construct/copy/destroy:
  431.       // NB: We overload ctors in some cases instead of using default
  432.       // arguments, per 17.4.4.4 para. 2 item 2.
  433.  
  434.       /**
  435.        *  @brief  Default constructor creates an empty string.
  436.        */
  437.       basic_string()
  438. #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
  439.       : _M_dataplus(_S_empty_rep()._M_refdata(), _Alloc()) { }
  440. #else
  441.       : _M_dataplus(_S_construct(size_type(), _CharT(), _Alloc()), _Alloc()){ }
  442. #endif
  443.  
  444.       /**
  445.        *  @brief  Construct an empty string using allocator @a a.
  446.        */
  447.       explicit
  448.       basic_string(const _Alloc& __a);
  449.  
  450.       // NB: per LWG issue 42, semantics different from IS:
  451.       /**
  452.        *  @brief  Construct string with copy of value of @a str.
  453.        *  @param  __str  Source string.
  454.        */
  455.       basic_string(const basic_string& __str);
  456.       /**
  457.        *  @brief  Construct string as copy of a substring.
  458.        *  @param  __str  Source string.
  459.        *  @param  __pos  Index of first character to copy from.
  460.        *  @param  __n  Number of characters to copy (default remainder).
  461.        */
  462.       basic_string(const basic_string& __str, size_type __pos,
  463.                    size_type __n = npos);
  464.       /**
  465.        *  @brief  Construct string as copy of a substring.
  466.        *  @param  __str  Source string.
  467.        *  @param  __pos  Index of first character to copy from.
  468.        *  @param  __n  Number of characters to copy.
  469.        *  @param  __a  Allocator to use.
  470.        */
  471.       basic_string(const basic_string& __str, size_type __pos,
  472.                    size_type __n, const _Alloc& __a);
  473.  
  474.       /**
  475.        *  @brief  Construct string initialized by a character %array.
  476.        *  @param  __s  Source character %array.
  477.        *  @param  __n  Number of characters to copy.
  478.        *  @param  __a  Allocator to use (default is default allocator).
  479.        *
  480.        *  NB: @a __s must have at least @a __n characters, &apos;\\0&apos;
  481.        *  has no special meaning.
  482.        */
  483.       basic_string(const _CharT* __s, size_type __n,
  484.                    const _Alloc& __a = _Alloc());
  485.       /**
  486.        *  @brief  Construct string as copy of a C string.
  487.        *  @param  __s  Source C string.
  488.        *  @param  __a  Allocator to use (default is default allocator).
  489.        */
  490.       basic_string(const _CharT* __s, const _Alloc& __a = _Alloc());
  491.       /**
  492.        *  @brief  Construct string as multiple characters.
  493.        *  @param  __n  Number of characters.
  494.        *  @param  __c  Character to use.
  495.        *  @param  __a  Allocator to use (default is default allocator).
  496.        */
  497.       basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc());
  498.  
  499. #if __cplusplus >= 201103L
  500.       /**
  501.        *  @brief  Move construct string.
  502.        *  @param  __str  Source string.
  503.        *
  504.        *  The newly-created string contains the exact contents of @a __str.
  505.        *  @a __str is a valid, but unspecified string.
  506.        **/
  507.       basic_string(basic_string&& __str) noexcept
  508.       : _M_dataplus(__str._M_dataplus)
  509.       {
  510. #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
  511.         __str._M_data(_S_empty_rep()._M_refdata());
  512. #else
  513.         __str._M_data(_S_construct(size_type(), _CharT(), get_allocator()));
  514. #endif
  515.       }
  516.  
  517.       /**
  518.        *  @brief  Construct string from an initializer %list.
  519.        *  @param  __l  std::initializer_list of characters.
  520.        *  @param  __a  Allocator to use (default is default allocator).
  521.        */
  522.       basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc());
  523. #endif // C++11
  524.  
  525.       /**
  526.        *  @brief  Construct string as copy of a range.
  527.        *  @param  __beg  Start of range.
  528.        *  @param  __end  End of range.
  529.        *  @param  __a  Allocator to use (default is default allocator).
  530.        */
  531.       template<class _InputIterator>
  532.         basic_string(_InputIterator __beg, _InputIterator __end,
  533.                      const _Alloc& __a = _Alloc());
  534.  
  535.       /**
  536.        *  @brief  Destroy the string instance.
  537.        */
  538.       ~basic_string() _GLIBCXX_NOEXCEPT
  539.       { _M_rep()->_M_dispose(this->get_allocator()); }
  540.  
  541.       /**
  542.        *  @brief  Assign the value of @a str to this string.
  543.        *  @param  __str  Source string.
  544.        */
  545.       basic_string&
  546.       operator=(const basic_string& __str)
  547.       { return this->assign(__str); }
  548.  
  549.       /**
  550.        *  @brief  Copy contents of @a s into this string.
  551.        *  @param  __s  Source null-terminated string.
  552.        */
  553.       basic_string&
  554.       operator=(const _CharT* __s)
  555.       { return this->assign(__s); }
  556.  
  557.       /**
  558.        *  @brief  Set value to string of length 1.
  559.        *  @param  __c  Source character.
  560.        *
  561.        *  Assigning to a character makes this string length 1 and
  562.        *  (*this)[0] == @a c.
  563.        */
  564.       basic_string&
  565.       operator=(_CharT __c)
  566.       {
  567.         this->assign(1, __c);
  568.         return *this;
  569.       }
  570.  
  571. #if __cplusplus >= 201103L
  572.       /**
  573.        *  @brief  Move assign the value of @a str to this string.
  574.        *  @param  __str  Source string.
  575.        *
  576.        *  The contents of @a str are moved into this string (without copying).
  577.        *  @a str is a valid, but unspecified string.
  578.        **/
  579.       basic_string&
  580.       operator=(basic_string&& __str)
  581.       {
  582.         // NB: DR 1204.
  583.         this->swap(__str);
  584.         return *this;
  585.       }
  586.  
  587.       /**
  588.        *  @brief  Set value to string constructed from initializer %list.
  589.        *  @param  __l  std::initializer_list.
  590.        */
  591.       basic_string&
  592.       operator=(initializer_list<_CharT> __l)
  593.       {
  594.         this->assign(__l.begin(), __l.size());
  595.         return *this;
  596.       }
  597. #endif // C++11
  598.  
  599.       // Iterators:
  600.       /**
  601.        *  Returns a read/write iterator that points to the first character in
  602.        *  the %string.  Unshares the string.
  603.        */
  604.       iterator
  605.       begin() _GLIBCXX_NOEXCEPT
  606.       {
  607.         _M_leak();
  608.         return iterator(_M_data());
  609.       }
  610.  
  611.       /**
  612.        *  Returns a read-only (constant) iterator that points to the first
  613.        *  character in the %string.
  614.        */
  615.       const_iterator
  616.       begin() const _GLIBCXX_NOEXCEPT
  617.       { return const_iterator(_M_data()); }
  618.  
  619.       /**
  620.        *  Returns a read/write iterator that points one past the last
  621.        *  character in the %string.  Unshares the string.
  622.        */
  623.       iterator
  624.       end() _GLIBCXX_NOEXCEPT
  625.       {
  626.         _M_leak();
  627.         return iterator(_M_data() + this->size());
  628.       }
  629.  
  630.       /**
  631.        *  Returns a read-only (constant) iterator that points one past the
  632.        *  last character in the %string.
  633.        */
  634.       const_iterator
  635.       end() const _GLIBCXX_NOEXCEPT
  636.       { return const_iterator(_M_data() + this->size()); }
  637.  
  638.       /**
  639.        *  Returns a read/write reverse iterator that points to the last
  640.        *  character in the %string.  Iteration is done in reverse element
  641.        *  order.  Unshares the string.
  642.        */
  643.       reverse_iterator
  644.       rbegin() _GLIBCXX_NOEXCEPT
  645.       { return reverse_iterator(this->end()); }
  646.  
  647.       /**
  648.        *  Returns a read-only (constant) reverse iterator that points
  649.        *  to the last character in the %string.  Iteration is done in
  650.        *  reverse element order.
  651.        */
  652.       const_reverse_iterator
  653.       rbegin() const _GLIBCXX_NOEXCEPT
  654.       { return const_reverse_iterator(this->end()); }
  655.  
  656.       /**
  657.        *  Returns a read/write reverse iterator that points to one before the
  658.        *  first character in the %string.  Iteration is done in reverse
  659.        *  element order.  Unshares the string.
  660.        */
  661.       reverse_iterator
  662.       rend() _GLIBCXX_NOEXCEPT
  663.       { return reverse_iterator(this->begin()); }
  664.  
  665.       /**
  666.        *  Returns a read-only (constant) reverse iterator that points
  667.        *  to one before the first character in the %string.  Iteration
  668.        *  is done in reverse element order.
  669.        */
  670.       const_reverse_iterator
  671.       rend() const _GLIBCXX_NOEXCEPT
  672.       { return const_reverse_iterator(this->begin()); }
  673.  
  674. #if __cplusplus >= 201103L
  675.       /**
  676.        *  Returns a read-only (constant) iterator that points to the first
  677.        *  character in the %string.
  678.        */
  679.       const_iterator
  680.       cbegin() const noexcept
  681.       { return const_iterator(this->_M_data()); }
  682.  
  683.       /**
  684.        *  Returns a read-only (constant) iterator that points one past the
  685.        *  last character in the %string.
  686.        */
  687.       const_iterator
  688.       cend() const noexcept
  689.       { return const_iterator(this->_M_data() + this->size()); }
  690.  
  691.       /**
  692.        *  Returns a read-only (constant) reverse iterator that points
  693.        *  to the last character in the %string.  Iteration is done in
  694.        *  reverse element order.
  695.        */
  696.       const_reverse_iterator
  697.       crbegin() const noexcept
  698.       { return const_reverse_iterator(this->end()); }
  699.  
  700.       /**
  701.        *  Returns a read-only (constant) reverse iterator that points
  702.        *  to one before the first character in the %string.  Iteration
  703.        *  is done in reverse element order.
  704.        */
  705.       const_reverse_iterator
  706.       crend() const noexcept
  707.       { return const_reverse_iterator(this->begin()); }
  708. #endif
  709.  
  710.     public:
  711.       // Capacity:
  712.       ///  Returns the number of characters in the string, not including any
  713.       ///  null-termination.
  714.       size_type
  715.       size() const _GLIBCXX_NOEXCEPT
  716.       { return _M_rep()->_M_length; }
  717.  
  718.       ///  Returns the number of characters in the string, not including any
  719.       ///  null-termination.
  720.       size_type
  721.       length() const _GLIBCXX_NOEXCEPT
  722.       { return _M_rep()->_M_length; }
  723.  
  724.       ///  Returns the size() of the largest possible %string.
  725.       size_type
  726.       max_size() const _GLIBCXX_NOEXCEPT
  727.       { return _Rep::_S_max_size; }
  728.  
  729.       /**
  730.        *  @brief  Resizes the %string to the specified number of characters.
  731.        *  @param  __n  Number of characters the %string should contain.
  732.        *  @param  __c  Character to fill any new elements.
  733.        *
  734.        *  This function will %resize the %string to the specified
  735.        *  number of characters.  If the number is smaller than the
  736.        *  %string's current size the %string is truncated, otherwise
  737.        *  the %string is extended and new elements are %set to @a __c.
  738.        */
  739.       void
  740.       resize(size_type __n, _CharT __c);
  741.  
  742.       /**
  743.        *  @brief  Resizes the %string to the specified number of characters.
  744.        *  @param  __n  Number of characters the %string should contain.
  745.        *
  746.        *  This function will resize the %string to the specified length.  If
  747.        *  the new size is smaller than the %string's current size the %string
  748.        *  is truncated, otherwise the %string is extended and new characters
  749.        *  are default-constructed.  For basic types such as char, this means
  750.        *  setting them to 0.
  751.        */
  752.       void
  753.       resize(size_type __n)
  754.       { this->resize(__n, _CharT()); }
  755.  
  756. #if __cplusplus >= 201103L
  757.       ///  A non-binding request to reduce capacity() to size().
  758.       void
  759.       shrink_to_fit()
  760.       {
  761.         if (capacity() > size())
  762.           {
  763.             __try
  764.               { reserve(0); }
  765.             __catch(...)
  766.               { }
  767.           }
  768.       }
  769. #endif
  770.  
  771.       /**
  772.        *  Returns the total number of characters that the %string can hold
  773.        *  before needing to allocate more memory.
  774.        */
  775.       size_type
  776.       capacity() const _GLIBCXX_NOEXCEPT
  777.       { return _M_rep()->_M_capacity; }
  778.  
  779.       /**
  780.        *  @brief  Attempt to preallocate enough memory for specified number of
  781.        *          characters.
  782.        *  @param  __res_arg  Number of characters required.
  783.        *  @throw  std::length_error  If @a __res_arg exceeds @c max_size().
  784.        *
  785.        *  This function attempts to reserve enough memory for the
  786.        *  %string to hold the specified number of characters.  If the
  787.        *  number requested is more than max_size(), length_error is
  788.        *  thrown.
  789.        *
  790.        *  The advantage of this function is that if optimal code is a
  791.        *  necessity and the user can determine the string length that will be
  792.        *  required, the user can reserve the memory in %advance, and thus
  793.        *  prevent a possible reallocation of memory and copying of %string
  794.        *  data.
  795.        */
  796.       void
  797.       reserve(size_type __res_arg = 0);
  798.  
  799.       /**
  800.        *  Erases the string, making it empty.
  801.        */
  802.       void
  803.       clear() _GLIBCXX_NOEXCEPT
  804.       { _M_mutate(0, this->size(), 0); }
  805.  
  806.       /**
  807.        *  Returns true if the %string is empty.  Equivalent to
  808.        *  <code>*this == ""</code>.
  809.        */
  810.       bool
  811.       empty() const _GLIBCXX_NOEXCEPT
  812.       { return this->size() == 0; }
  813.  
  814.       // Element access:
  815.       /**
  816.        *  @brief  Subscript access to the data contained in the %string.
  817.        *  @param  __pos  The index of the character to access.
  818.        *  @return  Read-only (constant) reference to the character.
  819.        *
  820.        *  This operator allows for easy, array-style, data access.
  821.        *  Note that data access with this operator is unchecked and
  822.        *  out_of_range lookups are not defined. (For checked lookups
  823.        *  see at().)
  824.        */
  825.       const_reference
  826.       operator[] (size_type __pos) const
  827.       {
  828.         _GLIBCXX_DEBUG_ASSERT(__pos <= size());
  829.         return _M_data()[__pos];
  830.       }
  831.  
  832.       /**
  833.        *  @brief  Subscript access to the data contained in the %string.
  834.        *  @param  __pos  The index of the character to access.
  835.        *  @return  Read/write reference to the character.
  836.        *
  837.        *  This operator allows for easy, array-style, data access.
  838.        *  Note that data access with this operator is unchecked and
  839.        *  out_of_range lookups are not defined. (For checked lookups
  840.        *  see at().)  Unshares the string.
  841.        */
  842.       reference
  843.       operator[](size_type __pos)
  844.       {
  845.         // allow pos == size() as v3 extension:
  846.         _GLIBCXX_DEBUG_ASSERT(__pos <= size());
  847.         // but be strict in pedantic mode:
  848.         _GLIBCXX_DEBUG_PEDASSERT(__pos < size());
  849.         _M_leak();
  850.         return _M_data()[__pos];
  851.       }
  852.  
  853.       /**
  854.        *  @brief  Provides access to the data contained in the %string.
  855.        *  @param __n The index of the character to access.
  856.        *  @return  Read-only (const) reference to the character.
  857.        *  @throw  std::out_of_range  If @a n is an invalid index.
  858.        *
  859.        *  This function provides for safer data access.  The parameter is
  860.        *  first checked that it is in the range of the string.  The function
  861.        *  throws out_of_range if the check fails.
  862.        */
  863.       const_reference
  864.       at(size_type __n) const
  865.       {
  866.         if (__n >= this->size())
  867.           __throw_out_of_range(__N("basic_string::at"));
  868.         return _M_data()[__n];
  869.       }
  870.  
  871.       /**
  872.        *  @brief  Provides access to the data contained in the %string.
  873.        *  @param __n The index of the character to access.
  874.        *  @return  Read/write reference to the character.
  875.        *  @throw  std::out_of_range  If @a n is an invalid index.
  876.        *
  877.        *  This function provides for safer data access.  The parameter is
  878.        *  first checked that it is in the range of the string.  The function
  879.        *  throws out_of_range if the check fails.  Success results in
  880.        *  unsharing the string.
  881.        */
  882.       reference
  883.       at(size_type __n)
  884.       {
  885.         if (__n >= size())
  886.           __throw_out_of_range(__N("basic_string::at"));
  887.         _M_leak();
  888.         return _M_data()[__n];
  889.       }
  890.  
  891. #if __cplusplus >= 201103L
  892.       /**
  893.        *  Returns a read/write reference to the data at the first
  894.        *  element of the %string.
  895.        */
  896.       reference
  897.       front()
  898.       { return operator[](0); }
  899.  
  900.       /**
  901.        *  Returns a read-only (constant) reference to the data at the first
  902.        *  element of the %string.
  903.        */
  904.       const_reference
  905.       front() const
  906.       { return operator[](0); }
  907.  
  908.       /**
  909.        *  Returns a read/write reference to the data at the last
  910.        *  element of the %string.
  911.        */
  912.       reference
  913.       back()
  914.       { return operator[](this->size() - 1); }
  915.  
  916.       /**
  917.        *  Returns a read-only (constant) reference to the data at the
  918.        *  last element of the %string.
  919.        */
  920.       const_reference
  921.       back() const
  922.       { return operator[](this->size() - 1); }
  923. #endif
  924.  
  925.       // Modifiers:
  926.       /**
  927.        *  @brief  Append a string to this string.
  928.        *  @param __str  The string to append.
  929.        *  @return  Reference to this string.
  930.        */
  931.       basic_string&
  932.       operator+=(const basic_string& __str)
  933.       { return this->append(__str); }
  934.  
  935.       /**
  936.        *  @brief  Append a C string.
  937.        *  @param __s  The C string to append.
  938.        *  @return  Reference to this string.
  939.        */
  940.       basic_string&
  941.       operator+=(const _CharT* __s)
  942.       { return this->append(__s); }
  943.  
  944.       /**
  945.        *  @brief  Append a character.
  946.        *  @param __c  The character to append.
  947.        *  @return  Reference to this string.
  948.        */
  949.       basic_string&
  950.       operator+=(_CharT __c)
  951.       {
  952.         this->push_back(__c);
  953.         return *this;
  954.       }
  955.  
  956. #if __cplusplus >= 201103L
  957.       /**
  958.        *  @brief  Append an initializer_list of characters.
  959.        *  @param __l  The initializer_list of characters to be appended.
  960.        *  @return  Reference to this string.
  961.        */
  962.       basic_string&
  963.       operator+=(initializer_list<_CharT> __l)
  964.       { return this->append(__l.begin(), __l.size()); }
  965. #endif // C++11
  966.  
  967.       /**
  968.        *  @brief  Append a string to this string.
  969.        *  @param __str  The string to append.
  970.        *  @return  Reference to this string.
  971.        */
  972.       basic_string&
  973.       append(const basic_string& __str);
  974.  
  975.       /**
  976.        *  @brief  Append a substring.
  977.        *  @param __str  The string to append.
  978.        *  @param __pos  Index of the first character of str to append.
  979.        *  @param __n  The number of characters to append.
  980.        *  @return  Reference to this string.
  981.        *  @throw  std::out_of_range if @a __pos is not a valid index.
  982.        *
  983.        *  This function appends @a __n characters from @a __str
  984.        *  starting at @a __pos to this string.  If @a __n is is larger
  985.        *  than the number of available characters in @a __str, the
  986.        *  remainder of @a __str is appended.
  987.        */
  988.       basic_string&
  989.       append(const basic_string& __str, size_type __pos, size_type __n);
  990.  
  991.       /**
  992.        *  @brief  Append a C substring.
  993.        *  @param __s  The C string to append.
  994.        *  @param __n  The number of characters to append.
  995.        *  @return  Reference to this string.
  996.        */
  997.       basic_string&
  998.       append(const _CharT* __s, size_type __n);
  999.  
  1000.       /**
  1001.        *  @brief  Append a C string.
  1002.        *  @param __s  The C string to append.
  1003.        *  @return  Reference to this string.
  1004.        */
  1005.       basic_string&
  1006.       append(const _CharT* __s)
  1007.       {
  1008.         __glibcxx_requires_string(__s);
  1009.         return this->append(__s, traits_type::length(__s));
  1010.       }
  1011.  
  1012.       /**
  1013.        *  @brief  Append multiple characters.
  1014.        *  @param __n  The number of characters to append.
  1015.        *  @param __c  The character to use.
  1016.        *  @return  Reference to this string.
  1017.        *
  1018.        *  Appends __n copies of __c to this string.
  1019.        */
  1020.       basic_string&
  1021.       append(size_type __n, _CharT __c);
  1022.  
  1023. #if __cplusplus >= 201103L
  1024.       /**
  1025.        *  @brief  Append an initializer_list of characters.
  1026.        *  @param __l  The initializer_list of characters to append.
  1027.        *  @return  Reference to this string.
  1028.        */
  1029.       basic_string&
  1030.       append(initializer_list<_CharT> __l)
  1031.       { return this->append(__l.begin(), __l.size()); }
  1032. #endif // C++11
  1033.  
  1034.       /**
  1035.        *  @brief  Append a range of characters.
  1036.        *  @param __first  Iterator referencing the first character to append.
  1037.        *  @param __last  Iterator marking the end of the range.
  1038.        *  @return  Reference to this string.
  1039.        *
  1040.        *  Appends characters in the range [__first,__last) to this string.
  1041.        */
  1042.       template<class _InputIterator>
  1043.         basic_string&
  1044.         append(_InputIterator __first, _InputIterator __last)
  1045.         { return this->replace(_M_iend(), _M_iend(), __first, __last); }
  1046.  
  1047.       /**
  1048.        *  @brief  Append a single character.
  1049.        *  @param __c  Character to append.
  1050.        */
  1051.       void
  1052.       push_back(_CharT __c)
  1053.       {
  1054.         const size_type __len = 1 + this->size();
  1055.         if (__len > this->capacity() || _M_rep()->_M_is_shared())
  1056.           this->reserve(__len);
  1057.         traits_type::assign(_M_data()[this->size()], __c);
  1058.         _M_rep()->_M_set_length_and_sharable(__len);
  1059.       }
  1060.  
  1061.       /**
  1062.        *  @brief  Set value to contents of another string.
  1063.        *  @param  __str  Source string to use.
  1064.        *  @return  Reference to this string.
  1065.        */
  1066.       basic_string&
  1067.       assign(const basic_string& __str);
  1068.  
  1069. #if __cplusplus >= 201103L
  1070.       /**
  1071.        *  @brief  Set value to contents of another string.
  1072.        *  @param  __str  Source string to use.
  1073.        *  @return  Reference to this string.
  1074.        *
  1075.        *  This function sets this string to the exact contents of @a __str.
  1076.        *  @a __str is a valid, but unspecified string.
  1077.        */
  1078.       basic_string&
  1079.       assign(basic_string&& __str)
  1080.       {
  1081.         this->swap(__str);
  1082.         return *this;
  1083.       }
  1084. #endif // C++11
  1085.  
  1086.       /**
  1087.        *  @brief  Set value to a substring of a string.
  1088.        *  @param __str  The string to use.
  1089.        *  @param __pos  Index of the first character of str.
  1090.        *  @param __n  Number of characters to use.
  1091.        *  @return  Reference to this string.
  1092.        *  @throw  std::out_of_range if @a pos is not a valid index.
  1093.        *
  1094.        *  This function sets this string to the substring of @a __str
  1095.        *  consisting of @a __n characters at @a __pos.  If @a __n is
  1096.        *  is larger than the number of available characters in @a
  1097.        *  __str, the remainder of @a __str is used.
  1098.        */
  1099.       basic_string&
  1100.       assign(const basic_string& __str, size_type __pos, size_type __n)
  1101.       { return this->assign(__str._M_data()
  1102.                             + __str._M_check(__pos, "basic_string::assign"),
  1103.                             __str._M_limit(__pos, __n)); }
  1104.  
  1105.       /**
  1106.        *  @brief  Set value to a C substring.
  1107.        *  @param __s  The C string to use.
  1108.        *  @param __n  Number of characters to use.
  1109.        *  @return  Reference to this string.
  1110.        *
  1111.        *  This function sets the value of this string to the first @a __n
  1112.        *  characters of @a __s.  If @a __n is is larger than the number of
  1113.        *  available characters in @a __s, the remainder of @a __s is used.
  1114.        */
  1115.       basic_string&
  1116.       assign(const _CharT* __s, size_type __n);
  1117.  
  1118.       /**
  1119.        *  @brief  Set value to contents of a C string.
  1120.        *  @param __s  The C string to use.
  1121.        *  @return  Reference to this string.
  1122.        *
  1123.        *  This function sets the value of this string to the value of @a __s.
  1124.        *  The data is copied, so there is no dependence on @a __s once the
  1125.        *  function returns.
  1126.        */
  1127.       basic_string&
  1128.       assign(const _CharT* __s)
  1129.       {
  1130.         __glibcxx_requires_string(__s);
  1131.         return this->assign(__s, traits_type::length(__s));
  1132.       }
  1133.  
  1134.       /**
  1135.        *  @brief  Set value to multiple characters.
  1136.        *  @param __n  Length of the resulting string.
  1137.        *  @param __c  The character to use.
  1138.        *  @return  Reference to this string.
  1139.        *
  1140.        *  This function sets the value of this string to @a __n copies of
  1141.        *  character @a __c.
  1142.        */
  1143.       basic_string&
  1144.       assign(size_type __n, _CharT __c)
  1145.       { return _M_replace_aux(size_type(0), this->size(), __n, __c); }
  1146.  
  1147.       /**
  1148.        *  @brief  Set value to a range of characters.
  1149.        *  @param __first  Iterator referencing the first character to append.
  1150.        *  @param __last  Iterator marking the end of the range.
  1151.        *  @return  Reference to this string.
  1152.        *
  1153.        *  Sets value of string to characters in the range [__first,__last).
  1154.       */
  1155.       template<class _InputIterator>
  1156.         basic_string&
  1157.         assign(_InputIterator __first, _InputIterator __last)
  1158.         { return this->replace(_M_ibegin(), _M_iend(), __first, __last); }
  1159.  
  1160. #if __cplusplus >= 201103L
  1161.       /**
  1162.        *  @brief  Set value to an initializer_list of characters.
  1163.        *  @param __l  The initializer_list of characters to assign.
  1164.        *  @return  Reference to this string.
  1165.        */
  1166.       basic_string&
  1167.       assign(initializer_list<_CharT> __l)
  1168.       { return this->assign(__l.begin(), __l.size()); }
  1169. #endif // C++11
  1170.  
  1171.       /**
  1172.        *  @brief  Insert multiple characters.
  1173.        *  @param __p  Iterator referencing location in string to insert at.
  1174.        *  @param __n  Number of characters to insert
  1175.        *  @param __c  The character to insert.
  1176.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1177.        *
  1178.        *  Inserts @a __n copies of character @a __c starting at the
  1179.        *  position referenced by iterator @a __p.  If adding
  1180.        *  characters causes the length to exceed max_size(),
  1181.        *  length_error is thrown.  The value of the string doesn't
  1182.        *  change if an error is thrown.
  1183.       */
  1184.       void
  1185.       insert(iterator __p, size_type __n, _CharT __c)
  1186.       { this->replace(__p, __p, __n, __c);  }
  1187.  
  1188.       /**
  1189.        *  @brief  Insert a range of characters.
  1190.        *  @param __p  Iterator referencing location in string to insert at.
  1191.        *  @param __beg  Start of range.
  1192.        *  @param __end  End of range.
  1193.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1194.        *
  1195.        *  Inserts characters in range [__beg,__end).  If adding
  1196.        *  characters causes the length to exceed max_size(),
  1197.        *  length_error is thrown.  The value of the string doesn't
  1198.        *  change if an error is thrown.
  1199.       */
  1200.       template<class _InputIterator>
  1201.         void
  1202.         insert(iterator __p, _InputIterator __beg, _InputIterator __end)
  1203.         { this->replace(__p, __p, __beg, __end); }
  1204.  
  1205. #if __cplusplus >= 201103L
  1206.       /**
  1207.        *  @brief  Insert an initializer_list of characters.
  1208.        *  @param __p  Iterator referencing location in string to insert at.
  1209.        *  @param __l  The initializer_list of characters to insert.
  1210.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1211.        */
  1212.       void
  1213.       insert(iterator __p, initializer_list<_CharT> __l)
  1214.       {
  1215.         _GLIBCXX_DEBUG_PEDASSERT(__p >= _M_ibegin() && __p <= _M_iend());
  1216.         this->insert(__p - _M_ibegin(), __l.begin(), __l.size());
  1217.       }
  1218. #endif // C++11
  1219.  
  1220.       /**
  1221.        *  @brief  Insert value of a string.
  1222.        *  @param __pos1  Iterator referencing location in string to insert at.
  1223.        *  @param __str  The string to insert.
  1224.        *  @return  Reference to this string.
  1225.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1226.        *
  1227.        *  Inserts value of @a __str starting at @a __pos1.  If adding
  1228.        *  characters causes the length to exceed max_size(),
  1229.        *  length_error is thrown.  The value of the string doesn't
  1230.        *  change if an error is thrown.
  1231.       */
  1232.       basic_string&
  1233.       insert(size_type __pos1, const basic_string& __str)
  1234.       { return this->insert(__pos1, __str, size_type(0), __str.size()); }
  1235.  
  1236.       /**
  1237.        *  @brief  Insert a substring.
  1238.        *  @param __pos1  Iterator referencing location in string to insert at.
  1239.        *  @param __str  The string to insert.
  1240.        *  @param __pos2  Start of characters in str to insert.
  1241.        *  @param __n  Number of characters to insert.
  1242.        *  @return  Reference to this string.
  1243.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1244.        *  @throw  std::out_of_range  If @a pos1 > size() or
  1245.        *  @a __pos2 > @a str.size().
  1246.        *
  1247.        *  Starting at @a pos1, insert @a __n character of @a __str
  1248.        *  beginning with @a __pos2.  If adding characters causes the
  1249.        *  length to exceed max_size(), length_error is thrown.  If @a
  1250.        *  __pos1 is beyond the end of this string or @a __pos2 is
  1251.        *  beyond the end of @a __str, out_of_range is thrown.  The
  1252.        *  value of the string doesn't change if an error is thrown.
  1253.       */
  1254.       basic_string&
  1255.       insert(size_type __pos1, const basic_string& __str,
  1256.              size_type __pos2, size_type __n)
  1257.       { return this->insert(__pos1, __str._M_data()
  1258.                             + __str._M_check(__pos2, "basic_string::insert"),
  1259.                             __str._M_limit(__pos2, __n)); }
  1260.  
  1261.       /**
  1262.        *  @brief  Insert a C substring.
  1263.        *  @param __pos  Iterator referencing location in string to insert at.
  1264.        *  @param __s  The C string to insert.
  1265.        *  @param __n  The number of characters to insert.
  1266.        *  @return  Reference to this string.
  1267.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1268.        *  @throw  std::out_of_range  If @a __pos is beyond the end of this
  1269.        *  string.
  1270.        *
  1271.        *  Inserts the first @a __n characters of @a __s starting at @a
  1272.        *  __pos.  If adding characters causes the length to exceed
  1273.        *  max_size(), length_error is thrown.  If @a __pos is beyond
  1274.        *  end(), out_of_range is thrown.  The value of the string
  1275.        *  doesn't change if an error is thrown.
  1276.       */
  1277.       basic_string&
  1278.       insert(size_type __pos, const _CharT* __s, size_type __n);
  1279.  
  1280.       /**
  1281.        *  @brief  Insert a C string.
  1282.        *  @param __pos  Iterator referencing location in string to insert at.
  1283.        *  @param __s  The C string to insert.
  1284.        *  @return  Reference to this string.
  1285.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1286.        *  @throw  std::out_of_range  If @a pos is beyond the end of this
  1287.        *  string.
  1288.        *
  1289.        *  Inserts the first @a n characters of @a __s starting at @a __pos.  If
  1290.        *  adding characters causes the length to exceed max_size(),
  1291.        *  length_error is thrown.  If @a __pos is beyond end(), out_of_range is
  1292.        *  thrown.  The value of the string doesn't change if an error is
  1293.        *  thrown.
  1294.       */
  1295.       basic_string&
  1296.       insert(size_type __pos, const _CharT* __s)
  1297.       {
  1298.         __glibcxx_requires_string(__s);
  1299.         return this->insert(__pos, __s, traits_type::length(__s));
  1300.       }
  1301.  
  1302.       /**
  1303.        *  @brief  Insert multiple characters.
  1304.        *  @param __pos  Index in string to insert at.
  1305.        *  @param __n  Number of characters to insert
  1306.        *  @param __c  The character to insert.
  1307.        *  @return  Reference to this string.
  1308.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1309.        *  @throw  std::out_of_range  If @a __pos is beyond the end of this
  1310.        *  string.
  1311.        *
  1312.        *  Inserts @a __n copies of character @a __c starting at index
  1313.        *  @a __pos.  If adding characters causes the length to exceed
  1314.        *  max_size(), length_error is thrown.  If @a __pos > length(),
  1315.        *  out_of_range is thrown.  The value of the string doesn't
  1316.        *  change if an error is thrown.
  1317.       */
  1318.       basic_string&
  1319.       insert(size_type __pos, size_type __n, _CharT __c)
  1320.       { return _M_replace_aux(_M_check(__pos, "basic_string::insert"),
  1321.                               size_type(0), __n, __c); }
  1322.  
  1323.       /**
  1324.        *  @brief  Insert one character.
  1325.        *  @param __p  Iterator referencing position in string to insert at.
  1326.        *  @param __c  The character to insert.
  1327.        *  @return  Iterator referencing newly inserted char.
  1328.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1329.        *
  1330.        *  Inserts character @a __c at position referenced by @a __p.
  1331.        *  If adding character causes the length to exceed max_size(),
  1332.        *  length_error is thrown.  If @a __p is beyond end of string,
  1333.        *  out_of_range is thrown.  The value of the string doesn't
  1334.        *  change if an error is thrown.
  1335.       */
  1336.       iterator
  1337.       insert(iterator __p, _CharT __c)
  1338.       {
  1339.         _GLIBCXX_DEBUG_PEDASSERT(__p >= _M_ibegin() && __p <= _M_iend());
  1340.         const size_type __pos = __p - _M_ibegin();
  1341.         _M_replace_aux(__pos, size_type(0), size_type(1), __c);
  1342.         _M_rep()->_M_set_leaked();
  1343.         return iterator(_M_data() + __pos);
  1344.       }
  1345.  
  1346.       /**
  1347.        *  @brief  Remove characters.
  1348.        *  @param __pos  Index of first character to remove (default 0).
  1349.        *  @param __n  Number of characters to remove (default remainder).
  1350.        *  @return  Reference to this string.
  1351.        *  @throw  std::out_of_range  If @a pos is beyond the end of this
  1352.        *  string.
  1353.        *
  1354.        *  Removes @a __n characters from this string starting at @a
  1355.        *  __pos.  The length of the string is reduced by @a __n.  If
  1356.        *  there are < @a __n characters to remove, the remainder of
  1357.        *  the string is truncated.  If @a __p is beyond end of string,
  1358.        *  out_of_range is thrown.  The value of the string doesn't
  1359.        *  change if an error is thrown.
  1360.       */
  1361.       basic_string&
  1362.       erase(size_type __pos = 0, size_type __n = npos)
  1363.       {
  1364.         _M_mutate(_M_check(__pos, "basic_string::erase"),
  1365.                   _M_limit(__pos, __n), size_type(0));
  1366.         return *this;
  1367.       }
  1368.  
  1369.       /**
  1370.        *  @brief  Remove one character.
  1371.        *  @param __position  Iterator referencing the character to remove.
  1372.        *  @return  iterator referencing same location after removal.
  1373.        *
  1374.        *  Removes the character at @a __position from this string. The value
  1375.        *  of the string doesn't change if an error is thrown.
  1376.       */
  1377.       iterator
  1378.       erase(iterator __position)
  1379.       {
  1380.         _GLIBCXX_DEBUG_PEDASSERT(__position >= _M_ibegin()
  1381.                                  && __position < _M_iend());
  1382.         const size_type __pos = __position - _M_ibegin();
  1383.         _M_mutate(__pos, size_type(1), size_type(0));
  1384.         _M_rep()->_M_set_leaked();
  1385.         return iterator(_M_data() + __pos);
  1386.       }
  1387.  
  1388.       /**
  1389.        *  @brief  Remove a range of characters.
  1390.        *  @param __first  Iterator referencing the first character to remove.
  1391.        *  @param __last  Iterator referencing the end of the range.
  1392.        *  @return  Iterator referencing location of first after removal.
  1393.        *
  1394.        *  Removes the characters in the range [first,last) from this string.
  1395.        *  The value of the string doesn't change if an error is thrown.
  1396.       */
  1397.       iterator
  1398.       erase(iterator __first, iterator __last);
  1399.  
  1400. #if __cplusplus >= 201103L
  1401.       /**
  1402.        *  @brief  Remove the last character.
  1403.        *
  1404.        *  The string must be non-empty.
  1405.        */
  1406.       void
  1407.       pop_back()
  1408.       { erase(size()-1, 1); }
  1409. #endif // C++11
  1410.  
  1411.       /**
  1412.        *  @brief  Replace characters with value from another string.
  1413.        *  @param __pos  Index of first character to replace.
  1414.        *  @param __n  Number of characters to be replaced.
  1415.        *  @param __str  String to insert.
  1416.        *  @return  Reference to this string.
  1417.        *  @throw  std::out_of_range  If @a pos is beyond the end of this
  1418.        *  string.
  1419.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1420.        *
  1421.        *  Removes the characters in the range [__pos,__pos+__n) from
  1422.        *  this string.  In place, the value of @a __str is inserted.
  1423.        *  If @a __pos is beyond end of string, out_of_range is thrown.
  1424.        *  If the length of the result exceeds max_size(), length_error
  1425.        *  is thrown.  The value of the string doesn't change if an
  1426.        *  error is thrown.
  1427.       */
  1428.       basic_string&
  1429.       replace(size_type __pos, size_type __n, const basic_string& __str)
  1430.       { return this->replace(__pos, __n, __str._M_data(), __str.size()); }
  1431.  
  1432.       /**
  1433.        *  @brief  Replace characters with value from another string.
  1434.        *  @param __pos1  Index of first character to replace.
  1435.        *  @param __n1  Number of characters to be replaced.
  1436.        *  @param __str  String to insert.
  1437.        *  @param __pos2  Index of first character of str to use.
  1438.        *  @param __n2  Number of characters from str to use.
  1439.        *  @return  Reference to this string.
  1440.        *  @throw  std::out_of_range  If @a __pos1 > size() or @a __pos2 >
  1441.        *  __str.size().
  1442.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1443.        *
  1444.        *  Removes the characters in the range [__pos1,__pos1 + n) from this
  1445.        *  string.  In place, the value of @a __str is inserted.  If @a __pos is
  1446.        *  beyond end of string, out_of_range is thrown.  If the length of the
  1447.        *  result exceeds max_size(), length_error is thrown.  The value of the
  1448.        *  string doesn't change if an error is thrown.
  1449.       */
  1450.       basic_string&
  1451.       replace(size_type __pos1, size_type __n1, const basic_string& __str,
  1452.               size_type __pos2, size_type __n2)
  1453.       { return this->replace(__pos1, __n1, __str._M_data()
  1454.                              + __str._M_check(__pos2, "basic_string::replace"),
  1455.                              __str._M_limit(__pos2, __n2)); }
  1456.  
  1457.       /**
  1458.        *  @brief  Replace characters with value of a C substring.
  1459.        *  @param __pos  Index of first character to replace.
  1460.        *  @param __n1  Number of characters to be replaced.
  1461.        *  @param __s  C string to insert.
  1462.        *  @param __n2  Number of characters from @a s to use.
  1463.        *  @return  Reference to this string.
  1464.        *  @throw  std::out_of_range  If @a pos1 > size().
  1465.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1466.        *
  1467.        *  Removes the characters in the range [__pos,__pos + __n1)
  1468.        *  from this string.  In place, the first @a __n2 characters of
  1469.        *  @a __s are inserted, or all of @a __s if @a __n2 is too large.  If
  1470.        *  @a __pos is beyond end of string, out_of_range is thrown.  If
  1471.        *  the length of result exceeds max_size(), length_error is
  1472.        *  thrown.  The value of the string doesn't change if an error
  1473.        *  is thrown.
  1474.       */
  1475.       basic_string&
  1476.       replace(size_type __pos, size_type __n1, const _CharT* __s,
  1477.               size_type __n2);
  1478.  
  1479.       /**
  1480.        *  @brief  Replace characters with value of a C string.
  1481.        *  @param __pos  Index of first character to replace.
  1482.        *  @param __n1  Number of characters to be replaced.
  1483.        *  @param __s  C string to insert.
  1484.        *  @return  Reference to this string.
  1485.        *  @throw  std::out_of_range  If @a pos > size().
  1486.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1487.        *
  1488.        *  Removes the characters in the range [__pos,__pos + __n1)
  1489.        *  from this string.  In place, the characters of @a __s are
  1490.        *  inserted.  If @a __pos is beyond end of string, out_of_range
  1491.        *  is thrown.  If the length of result exceeds max_size(),
  1492.        *  length_error is thrown.  The value of the string doesn't
  1493.        *  change if an error is thrown.
  1494.       */
  1495.       basic_string&
  1496.       replace(size_type __pos, size_type __n1, const _CharT* __s)
  1497.       {
  1498.         __glibcxx_requires_string(__s);
  1499.         return this->replace(__pos, __n1, __s, traits_type::length(__s));
  1500.       }
  1501.  
  1502.       /**
  1503.        *  @brief  Replace characters with multiple characters.
  1504.        *  @param __pos  Index of first character to replace.
  1505.        *  @param __n1  Number of characters to be replaced.
  1506.        *  @param __n2  Number of characters to insert.
  1507.        *  @param __c  Character to insert.
  1508.        *  @return  Reference to this string.
  1509.        *  @throw  std::out_of_range  If @a __pos > size().
  1510.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1511.        *
  1512.        *  Removes the characters in the range [pos,pos + n1) from this
  1513.        *  string.  In place, @a __n2 copies of @a __c are inserted.
  1514.        *  If @a __pos is beyond end of string, out_of_range is thrown.
  1515.        *  If the length of result exceeds max_size(), length_error is
  1516.        *  thrown.  The value of the string doesn't change if an error
  1517.        *  is thrown.
  1518.       */
  1519.       basic_string&
  1520.       replace(size_type __pos, size_type __n1, size_type __n2, _CharT __c)
  1521.       { return _M_replace_aux(_M_check(__pos, "basic_string::replace"),
  1522.                               _M_limit(__pos, __n1), __n2, __c); }
  1523.  
  1524.       /**
  1525.        *  @brief  Replace range of characters with string.
  1526.        *  @param __i1  Iterator referencing start of range to replace.
  1527.        *  @param __i2  Iterator referencing end of range to replace.
  1528.        *  @param __str  String value to insert.
  1529.        *  @return  Reference to this string.
  1530.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1531.        *
  1532.        *  Removes the characters in the range [__i1,__i2).  In place,
  1533.        *  the value of @a __str is inserted.  If the length of result
  1534.        *  exceeds max_size(), length_error is thrown.  The value of
  1535.        *  the string doesn't change if an error is thrown.
  1536.       */
  1537.       basic_string&
  1538.       replace(iterator __i1, iterator __i2, const basic_string& __str)
  1539.       { return this->replace(__i1, __i2, __str._M_data(), __str.size()); }
  1540.  
  1541.       /**
  1542.        *  @brief  Replace range of characters with C substring.
  1543.        *  @param __i1  Iterator referencing start of range to replace.
  1544.        *  @param __i2  Iterator referencing end of range to replace.
  1545.        *  @param __s  C string value to insert.
  1546.        *  @param __n  Number of characters from s to insert.
  1547.        *  @return  Reference to this string.
  1548.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1549.        *
  1550.        *  Removes the characters in the range [__i1,__i2).  In place,
  1551.        *  the first @a __n characters of @a __s are inserted.  If the
  1552.        *  length of result exceeds max_size(), length_error is thrown.
  1553.        *  The value of the string doesn't change if an error is
  1554.        *  thrown.
  1555.       */
  1556.       basic_string&
  1557.       replace(iterator __i1, iterator __i2, const _CharT* __s, size_type __n)
  1558.       {
  1559.         _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
  1560.                                  && __i2 <= _M_iend());
  1561.         return this->replace(__i1 - _M_ibegin(), __i2 - __i1, __s, __n);
  1562.       }
  1563.  
  1564.       /**
  1565.        *  @brief  Replace range of characters with C string.
  1566.        *  @param __i1  Iterator referencing start of range to replace.
  1567.        *  @param __i2  Iterator referencing end of range to replace.
  1568.        *  @param __s  C string value to insert.
  1569.        *  @return  Reference to this string.
  1570.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1571.        *
  1572.        *  Removes the characters in the range [__i1,__i2).  In place,
  1573.        *  the characters of @a __s are inserted.  If the length of
  1574.        *  result exceeds max_size(), length_error is thrown.  The
  1575.        *  value of the string doesn't change if an error is thrown.
  1576.       */
  1577.       basic_string&
  1578.       replace(iterator __i1, iterator __i2, const _CharT* __s)
  1579.       {
  1580.         __glibcxx_requires_string(__s);
  1581.         return this->replace(__i1, __i2, __s, traits_type::length(__s));
  1582.       }
  1583.  
  1584.       /**
  1585.        *  @brief  Replace range of characters with multiple characters
  1586.        *  @param __i1  Iterator referencing start of range to replace.
  1587.        *  @param __i2  Iterator referencing end of range to replace.
  1588.        *  @param __n  Number of characters to insert.
  1589.        *  @param __c  Character to insert.
  1590.        *  @return  Reference to this string.
  1591.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1592.        *
  1593.        *  Removes the characters in the range [__i1,__i2).  In place,
  1594.        *  @a __n copies of @a __c are inserted.  If the length of
  1595.        *  result exceeds max_size(), length_error is thrown.  The
  1596.        *  value of the string doesn't change if an error is thrown.
  1597.       */
  1598.       basic_string&
  1599.       replace(iterator __i1, iterator __i2, size_type __n, _CharT __c)
  1600.       {
  1601.         _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
  1602.                                  && __i2 <= _M_iend());
  1603.         return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __c);
  1604.       }
  1605.  
  1606.       /**
  1607.        *  @brief  Replace range of characters with range.
  1608.        *  @param __i1  Iterator referencing start of range to replace.
  1609.        *  @param __i2  Iterator referencing end of range to replace.
  1610.        *  @param __k1  Iterator referencing start of range to insert.
  1611.        *  @param __k2  Iterator referencing end of range to insert.
  1612.        *  @return  Reference to this string.
  1613.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1614.        *
  1615.        *  Removes the characters in the range [__i1,__i2).  In place,
  1616.        *  characters in the range [__k1,__k2) are inserted.  If the
  1617.        *  length of result exceeds max_size(), length_error is thrown.
  1618.        *  The value of the string doesn't change if an error is
  1619.        *  thrown.
  1620.       */
  1621.       template<class _InputIterator>
  1622.         basic_string&
  1623.         replace(iterator __i1, iterator __i2,
  1624.                 _InputIterator __k1, _InputIterator __k2)
  1625.         {
  1626.           _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
  1627.                                    && __i2 <= _M_iend());
  1628.           __glibcxx_requires_valid_range(__k1, __k2);
  1629.           typedef typename std::__is_integer<_InputIterator>::__type _Integral;
  1630.           return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral());
  1631.         }
  1632.  
  1633.       // Specializations for the common case of pointer and iterator:
  1634.       // useful to avoid the overhead of temporary buffering in _M_replace.
  1635.       basic_string&
  1636.       replace(iterator __i1, iterator __i2, _CharT* __k1, _CharT* __k2)
  1637.       {
  1638.         _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
  1639.                                  && __i2 <= _M_iend());
  1640.         __glibcxx_requires_valid_range(__k1, __k2);
  1641.         return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
  1642.                              __k1, __k2 - __k1);
  1643.       }
  1644.  
  1645.       basic_string&
  1646.       replace(iterator __i1, iterator __i2,
  1647.               const _CharT* __k1, const _CharT* __k2)
  1648.       {
  1649.         _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
  1650.                                  && __i2 <= _M_iend());
  1651.         __glibcxx_requires_valid_range(__k1, __k2);
  1652.         return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
  1653.                              __k1, __k2 - __k1);
  1654.       }
  1655.  
  1656.       basic_string&
  1657.       replace(iterator __i1, iterator __i2, iterator __k1, iterator __k2)
  1658.       {
  1659.         _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
  1660.                                  && __i2 <= _M_iend());
  1661.         __glibcxx_requires_valid_range(__k1, __k2);
  1662.         return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
  1663.                              __k1.base(), __k2 - __k1);
  1664.       }
  1665.  
  1666.       basic_string&
  1667.       replace(iterator __i1, iterator __i2,
  1668.               const_iterator __k1, const_iterator __k2)
  1669.       {
  1670.         _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
  1671.                                  && __i2 <= _M_iend());
  1672.         __glibcxx_requires_valid_range(__k1, __k2);
  1673.         return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
  1674.                              __k1.base(), __k2 - __k1);
  1675.       }
  1676.      
  1677. #if __cplusplus >= 201103L
  1678.       /**
  1679.        *  @brief  Replace range of characters with initializer_list.
  1680.        *  @param __i1  Iterator referencing start of range to replace.
  1681.        *  @param __i2  Iterator referencing end of range to replace.
  1682.        *  @param __l  The initializer_list of characters to insert.
  1683.        *  @return  Reference to this string.
  1684.        *  @throw  std::length_error  If new length exceeds @c max_size().
  1685.        *
  1686.        *  Removes the characters in the range [__i1,__i2).  In place,
  1687.        *  characters in the range [__k1,__k2) are inserted.  If the
  1688.        *  length of result exceeds max_size(), length_error is thrown.
  1689.        *  The value of the string doesn't change if an error is
  1690.        *  thrown.
  1691.       */
  1692.       basic_string& replace(iterator __i1, iterator __i2,
  1693.                             initializer_list<_CharT> __l)
  1694.       { return this->replace(__i1, __i2, __l.begin(), __l.end()); }
  1695. #endif // C++11
  1696.  
  1697.     private:
  1698.       template<class _Integer>
  1699.         basic_string&
  1700.         _M_replace_dispatch(iterator __i1, iterator __i2, _Integer __n,
  1701.                             _Integer __val, __true_type)
  1702.         { return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __val); }
  1703.  
  1704.       template<class _InputIterator>
  1705.         basic_string&
  1706.         _M_replace_dispatch(iterator __i1, iterator __i2, _InputIterator __k1,
  1707.                             _InputIterator __k2, __false_type);
  1708.  
  1709.       basic_string&
  1710.       _M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
  1711.                      _CharT __c);
  1712.  
  1713.       basic_string&
  1714.       _M_replace_safe(size_type __pos1, size_type __n1, const _CharT* __s,
  1715.                       size_type __n2);
  1716.  
  1717.       // _S_construct_aux is used to implement the 21.3.1 para 15 which
  1718.       // requires special behaviour if _InIter is an integral type
  1719.       template<class _InIterator>
  1720.         static _CharT*
  1721.         _S_construct_aux(_InIterator __beg, _InIterator __end,
  1722.                          const _Alloc& __a, __false_type)
  1723.         {
  1724.           typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
  1725.           return _S_construct(__beg, __end, __a, _Tag());
  1726.         }
  1727.  
  1728.       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  1729.       // 438. Ambiguity in the "do the right thing" clause
  1730.       template<class _Integer>
  1731.         static _CharT*
  1732.         _S_construct_aux(_Integer __beg, _Integer __end,
  1733.                          const _Alloc& __a, __true_type)
  1734.         { return _S_construct_aux_2(static_cast<size_type>(__beg),
  1735.                                     __end, __a); }
  1736.  
  1737.       static _CharT*
  1738.       _S_construct_aux_2(size_type __req, _CharT __c, const _Alloc& __a)
  1739.       { return _S_construct(__req, __c, __a); }
  1740.  
  1741.       template<class _InIterator>
  1742.         static _CharT*
  1743.         _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a)
  1744.         {
  1745.           typedef typename std::__is_integer<_InIterator>::__type _Integral;
  1746.           return _S_construct_aux(__beg, __end, __a, _Integral());
  1747.         }
  1748.  
  1749.       // For Input Iterators, used in istreambuf_iterators, etc.
  1750.       template<class _InIterator>
  1751.         static _CharT*
  1752.          _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a,
  1753.                       input_iterator_tag);
  1754.  
  1755.       // For forward_iterators up to random_access_iterators, used for
  1756.       // string::iterator, _CharT*, etc.
  1757.       template<class _FwdIterator>
  1758.         static _CharT*
  1759.         _S_construct(_FwdIterator __beg, _FwdIterator __end, const _Alloc& __a,
  1760.                      forward_iterator_tag);
  1761.  
  1762.       static _CharT*
  1763.       _S_construct(size_type __req, _CharT __c, const _Alloc& __a);
  1764.  
  1765.     public:
  1766.  
  1767.       /**
  1768.        *  @brief  Copy substring into C string.
  1769.        *  @param __s  C string to copy value into.
  1770.        *  @param __n  Number of characters to copy.
  1771.        *  @param __pos  Index of first character to copy.
  1772.        *  @return  Number of characters actually copied
  1773.        *  @throw  std::out_of_range  If __pos > size().
  1774.        *
  1775.        *  Copies up to @a __n characters starting at @a __pos into the
  1776.        *  C string @a __s.  If @a __pos is %greater than size(),
  1777.        *  out_of_range is thrown.
  1778.       */
  1779.       size_type
  1780.       copy(_CharT* __s, size_type __n, size_type __pos = 0) const;
  1781.  
  1782.       /**
  1783.        *  @brief  Swap contents with another string.
  1784.        *  @param __s  String to swap with.
  1785.        *
  1786.        *  Exchanges the contents of this string with that of @a __s in constant
  1787.        *  time.
  1788.       */
  1789.       void
  1790.       swap(basic_string& __s);
  1791.  
  1792.       // String operations:
  1793.       /**
  1794.        *  @brief  Return const pointer to null-terminated contents.
  1795.        *
  1796.        *  This is a handle to internal data.  Do not modify or dire things may
  1797.        *  happen.
  1798.       */
  1799.       const _CharT*
  1800.       c_str() const _GLIBCXX_NOEXCEPT
  1801.       { return _M_data(); }
  1802.  
  1803.       /**
  1804.        *  @brief  Return const pointer to contents.
  1805.        *
  1806.        *  This is a handle to internal data.  Do not modify or dire things may
  1807.        *  happen.
  1808.       */
  1809.       const _CharT*
  1810.       data() const _GLIBCXX_NOEXCEPT
  1811.       { return _M_data(); }
  1812.  
  1813.       /**
  1814.        *  @brief  Return copy of allocator used to construct this string.
  1815.       */
  1816.       allocator_type
  1817.       get_allocator() const _GLIBCXX_NOEXCEPT
  1818.       { return _M_dataplus; }
  1819.  
  1820.       /**
  1821.        *  @brief  Find position of a C substring.
  1822.        *  @param __s  C string to locate.
  1823.        *  @param __pos  Index of character to search from.
  1824.        *  @param __n  Number of characters from @a s to search for.
  1825.        *  @return  Index of start of first occurrence.
  1826.        *
  1827.        *  Starting from @a __pos, searches forward for the first @a
  1828.        *  __n characters in @a __s within this string.  If found,
  1829.        *  returns the index where it begins.  If not found, returns
  1830.        *  npos.
  1831.       */
  1832.       size_type
  1833.       find(const _CharT* __s, size_type __pos, size_type __n) const;
  1834.  
  1835.       /**
  1836.        *  @brief  Find position of a string.
  1837.        *  @param __str  String to locate.
  1838.        *  @param __pos  Index of character to search from (default 0).
  1839.        *  @return  Index of start of first occurrence.
  1840.        *
  1841.        *  Starting from @a __pos, searches forward for value of @a __str within
  1842.        *  this string.  If found, returns the index where it begins.  If not
  1843.        *  found, returns npos.
  1844.       */
  1845.       size_type
  1846.       find(const basic_string& __str, size_type __pos = 0) const
  1847.         _GLIBCXX_NOEXCEPT
  1848.       { return this->find(__str.data(), __pos, __str.size()); }
  1849.  
  1850.       /**
  1851.        *  @brief  Find position of a C string.
  1852.        *  @param __s  C string to locate.
  1853.        *  @param __pos  Index of character to search from (default 0).
  1854.        *  @return  Index of start of first occurrence.
  1855.        *
  1856.        *  Starting from @a __pos, searches forward for the value of @a
  1857.        *  __s within this string.  If found, returns the index where
  1858.        *  it begins.  If not found, returns npos.
  1859.       */
  1860.       size_type
  1861.       find(const _CharT* __s, size_type __pos = 0) const
  1862.       {
  1863.         __glibcxx_requires_string(__s);
  1864.         return this->find(__s, __pos, traits_type::length(__s));
  1865.       }
  1866.  
  1867.       /**
  1868.        *  @brief  Find position of a character.
  1869.        *  @param __c  Character to locate.
  1870.        *  @param __pos  Index of character to search from (default 0).
  1871.        *  @return  Index of first occurrence.
  1872.        *
  1873.        *  Starting from @a __pos, searches forward for @a __c within
  1874.        *  this string.  If found, returns the index where it was
  1875.        *  found.  If not found, returns npos.
  1876.       */
  1877.       size_type
  1878.       find(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT;
  1879.  
  1880.       /**
  1881.        *  @brief  Find last position of a string.
  1882.        *  @param __str  String to locate.
  1883.        *  @param __pos  Index of character to search back from (default end).
  1884.        *  @return  Index of start of last occurrence.
  1885.        *
  1886.        *  Starting from @a __pos, searches backward for value of @a
  1887.        *  __str within this string.  If found, returns the index where
  1888.        *  it begins.  If not found, returns npos.
  1889.       */
  1890.       size_type
  1891.       rfind(const basic_string& __str, size_type __pos = npos) const
  1892.         _GLIBCXX_NOEXCEPT
  1893.       { return this->rfind(__str.data(), __pos, __str.size()); }
  1894.  
  1895.       /**
  1896.        *  @brief  Find last position of a C substring.
  1897.        *  @param __s  C string to locate.
  1898.        *  @param __pos  Index of character to search back from.
  1899.        *  @param __n  Number of characters from s to search for.
  1900.        *  @return  Index of start of last occurrence.
  1901.        *
  1902.        *  Starting from @a __pos, searches backward for the first @a
  1903.        *  __n characters in @a __s within this string.  If found,
  1904.        *  returns the index where it begins.  If not found, returns
  1905.        *  npos.
  1906.       */
  1907.       size_type
  1908.       rfind(const _CharT* __s, size_type __pos, size_type __n) const;
  1909.  
  1910.       /**
  1911.        *  @brief  Find last position of a C string.
  1912.        *  @param __s  C string to locate.
  1913.        *  @param __pos  Index of character to start search at (default end).
  1914.        *  @return  Index of start of  last occurrence.
  1915.        *
  1916.        *  Starting from @a __pos, searches backward for the value of
  1917.        *  @a __s within this string.  If found, returns the index
  1918.        *  where it begins.  If not found, returns npos.
  1919.       */
  1920.       size_type
  1921.       rfind(const _CharT* __s, size_type __pos = npos) const
  1922.       {
  1923.         __glibcxx_requires_string(__s);
  1924.         return this->rfind(__s, __pos, traits_type::length(__s));
  1925.       }
  1926.  
  1927.       /**
  1928.        *  @brief  Find last position of a character.
  1929.        *  @param __c  Character to locate.
  1930.        *  @param __pos  Index of character to search back from (default end).
  1931.        *  @return  Index of last occurrence.
  1932.        *
  1933.        *  Starting from @a __pos, searches backward for @a __c within
  1934.        *  this string.  If found, returns the index where it was
  1935.        *  found.  If not found, returns npos.
  1936.       */
  1937.       size_type
  1938.       rfind(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT;
  1939.  
  1940.       /**
  1941.        *  @brief  Find position of a character of string.
  1942.        *  @param __str  String containing characters to locate.
  1943.        *  @param __pos  Index of character to search from (default 0).
  1944.        *  @return  Index of first occurrence.
  1945.        *
  1946.        *  Starting from @a __pos, searches forward for one of the
  1947.        *  characters of @a __str within this string.  If found,
  1948.        *  returns the index where it was found.  If not found, returns
  1949.        *  npos.
  1950.       */
  1951.       size_type
  1952.       find_first_of(const basic_string& __str, size_type __pos = 0) const
  1953.         _GLIBCXX_NOEXCEPT
  1954.       { return this->find_first_of(__str.data(), __pos, __str.size()); }
  1955.  
  1956.       /**
  1957.        *  @brief  Find position of a character of C substring.
  1958.        *  @param __s  String containing characters to locate.
  1959.        *  @param __pos  Index of character to search from.
  1960.        *  @param __n  Number of characters from s to search for.
  1961.        *  @return  Index of first occurrence.
  1962.        *
  1963.        *  Starting from @a __pos, searches forward for one of the
  1964.        *  first @a __n characters of @a __s within this string.  If
  1965.        *  found, returns the index where it was found.  If not found,
  1966.        *  returns npos.
  1967.       */
  1968.       size_type
  1969.       find_first_of(const _CharT* __s, size_type __pos, size_type __n) const;
  1970.  
  1971.       /**
  1972.        *  @brief  Find position of a character of C string.
  1973.        *  @param __s  String containing characters to locate.
  1974.        *  @param __pos  Index of character to search from (default 0).
  1975.        *  @return  Index of first occurrence.
  1976.        *
  1977.        *  Starting from @a __pos, searches forward for one of the
  1978.        *  characters of @a __s within this string.  If found, returns
  1979.        *  the index where it was found.  If not found, returns npos.
  1980.       */
  1981.       size_type
  1982.       find_first_of(const _CharT* __s, size_type __pos = 0) const
  1983.       {
  1984.         __glibcxx_requires_string(__s);
  1985.         return this->find_first_of(__s, __pos, traits_type::length(__s));
  1986.       }
  1987.  
  1988.       /**
  1989.        *  @brief  Find position of a character.
  1990.        *  @param __c  Character to locate.
  1991.        *  @param __pos  Index of character to search from (default 0).
  1992.        *  @return  Index of first occurrence.
  1993.        *
  1994.        *  Starting from @a __pos, searches forward for the character
  1995.        *  @a __c within this string.  If found, returns the index
  1996.        *  where it was found.  If not found, returns npos.
  1997.        *
  1998.        *  Note: equivalent to find(__c, __pos).
  1999.       */
  2000.       size_type
  2001.       find_first_of(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
  2002.       { return this->find(__c, __pos); }
  2003.  
  2004.       /**
  2005.        *  @brief  Find last position of a character of string.
  2006.        *  @param __str  String containing characters to locate.
  2007.        *  @param __pos  Index of character to search back from (default end).
  2008.        *  @return  Index of last occurrence.
  2009.        *
  2010.        *  Starting from @a __pos, searches backward for one of the
  2011.        *  characters of @a __str within this string.  If found,
  2012.        *  returns the index where it was found.  If not found, returns
  2013.        *  npos.
  2014.       */
  2015.       size_type
  2016.       find_last_of(const basic_string& __str, size_type __pos = npos) const
  2017.         _GLIBCXX_NOEXCEPT
  2018.       { return this->find_last_of(__str.data(), __pos, __str.size()); }
  2019.  
  2020.       /**
  2021.        *  @brief  Find last position of a character of C substring.
  2022.        *  @param __s  C string containing characters to locate.
  2023.        *  @param __pos  Index of character to search back from.
  2024.        *  @param __n  Number of characters from s to search for.
  2025.        *  @return  Index of last occurrence.
  2026.        *
  2027.        *  Starting from @a __pos, searches backward for one of the
  2028.        *  first @a __n characters of @a __s within this string.  If
  2029.        *  found, returns the index where it was found.  If not found,
  2030.        *  returns npos.
  2031.       */
  2032.       size_type
  2033.       find_last_of(const _CharT* __s, size_type __pos, size_type __n) const;
  2034.  
  2035.       /**
  2036.        *  @brief  Find last position of a character of C string.
  2037.        *  @param __s  C string containing characters to locate.
  2038.        *  @param __pos  Index of character to search back from (default end).
  2039.        *  @return  Index of last occurrence.
  2040.        *
  2041.        *  Starting from @a __pos, searches backward for one of the
  2042.        *  characters of @a __s within this string.  If found, returns
  2043.        *  the index where it was found.  If not found, returns npos.
  2044.       */
  2045.       size_type
  2046.       find_last_of(const _CharT* __s, size_type __pos = npos) const
  2047.       {
  2048.         __glibcxx_requires_string(__s);
  2049.         return this->find_last_of(__s, __pos, traits_type::length(__s));
  2050.       }
  2051.  
  2052.       /**
  2053.        *  @brief  Find last position of a character.
  2054.        *  @param __c  Character to locate.
  2055.        *  @param __pos  Index of character to search back from (default end).
  2056.        *  @return  Index of last occurrence.
  2057.        *
  2058.        *  Starting from @a __pos, searches backward for @a __c within
  2059.        *  this string.  If found, returns the index where it was
  2060.        *  found.  If not found, returns npos.
  2061.        *
  2062.        *  Note: equivalent to rfind(__c, __pos).
  2063.       */
  2064.       size_type
  2065.       find_last_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
  2066.       { return this->rfind(__c, __pos); }
  2067.  
  2068.       /**
  2069.        *  @brief  Find position of a character not in string.
  2070.        *  @param __str  String containing characters to avoid.
  2071.        *  @param __pos  Index of character to search from (default 0).
  2072.        *  @return  Index of first occurrence.
  2073.        *
  2074.        *  Starting from @a __pos, searches forward for a character not contained
  2075.        *  in @a __str within this string.  If found, returns the index where it
  2076.        *  was found.  If not found, returns npos.
  2077.       */
  2078.       size_type
  2079.       find_first_not_of(const basic_string& __str, size_type __pos = 0) const
  2080.         _GLIBCXX_NOEXCEPT
  2081.       { return this->find_first_not_of(__str.data(), __pos, __str.size()); }
  2082.  
  2083.       /**
  2084.        *  @brief  Find position of a character not in C substring.
  2085.        *  @param __s  C string containing characters to avoid.
  2086.        *  @param __pos  Index of character to search from.
  2087.        *  @param __n  Number of characters from __s to consider.
  2088.        *  @return  Index of first occurrence.
  2089.        *
  2090.        *  Starting from @a __pos, searches forward for a character not
  2091.        *  contained in the first @a __n characters of @a __s within
  2092.        *  this string.  If found, returns the index where it was
  2093.        *  found.  If not found, returns npos.
  2094.       */
  2095.       size_type
  2096.       find_first_not_of(const _CharT* __s, size_type __pos,
  2097.                         size_type __n) const;
  2098.  
  2099.       /**
  2100.        *  @brief  Find position of a character not in C string.
  2101.        *  @param __s  C string containing characters to avoid.
  2102.        *  @param __pos  Index of character to search from (default 0).
  2103.        *  @return  Index of first occurrence.
  2104.        *
  2105.        *  Starting from @a __pos, searches forward for a character not
  2106.        *  contained in @a __s within this string.  If found, returns
  2107.        *  the index where it was found.  If not found, returns npos.
  2108.       */
  2109.       size_type
  2110.       find_first_not_of(const _CharT* __s, size_type __pos = 0) const
  2111.       {
  2112.         __glibcxx_requires_string(__s);
  2113.         return this->find_first_not_of(__s, __pos, traits_type::length(__s));
  2114.       }
  2115.  
  2116.       /**
  2117.        *  @brief  Find position of a different character.
  2118.        *  @param __c  Character to avoid.
  2119.        *  @param __pos  Index of character to search from (default 0).
  2120.        *  @return  Index of first occurrence.
  2121.        *
  2122.        *  Starting from @a __pos, searches forward for a character
  2123.        *  other than @a __c within this string.  If found, returns the
  2124.        *  index where it was found.  If not found, returns npos.
  2125.       */
  2126.       size_type
  2127.       find_first_not_of(_CharT __c, size_type __pos = 0) const
  2128.         _GLIBCXX_NOEXCEPT;
  2129.  
  2130.       /**
  2131.        *  @brief  Find last position of a character not in string.
  2132.        *  @param __str  String containing characters to avoid.
  2133.        *  @param __pos  Index of character to search back from (default end).
  2134.        *  @return  Index of last occurrence.
  2135.        *
  2136.        *  Starting from @a __pos, searches backward for a character
  2137.        *  not contained in @a __str within this string.  If found,
  2138.        *  returns the index where it was found.  If not found, returns
  2139.        *  npos.
  2140.       */
  2141.       size_type
  2142.       find_last_not_of(const basic_string& __str, size_type __pos = npos) const
  2143.         _GLIBCXX_NOEXCEPT
  2144.       { return this->find_last_not_of(__str.data(), __pos, __str.size()); }
  2145.  
  2146.       /**
  2147.        *  @brief  Find last position of a character not in C substring.
  2148.        *  @param __s  C string containing characters to avoid.
  2149.        *  @param __pos  Index of character to search back from.
  2150.        *  @param __n  Number of characters from s to consider.
  2151.        *  @return  Index of last occurrence.
  2152.        *
  2153.        *  Starting from @a __pos, searches backward for a character not
  2154.        *  contained in the first @a __n characters of @a __s within this string.
  2155.        *  If found, returns the index where it was found.  If not found,
  2156.        *  returns npos.
  2157.       */
  2158.       size_type
  2159.       find_last_not_of(const _CharT* __s, size_type __pos,
  2160.                        size_type __n) const;
  2161.       /**
  2162.        *  @brief  Find last position of a character not in C string.
  2163.        *  @param __s  C string containing characters to avoid.
  2164.        *  @param __pos  Index of character to search back from (default end).
  2165.        *  @return  Index of last occurrence.
  2166.        *
  2167.        *  Starting from @a __pos, searches backward for a character
  2168.        *  not contained in @a __s within this string.  If found,
  2169.        *  returns the index where it was found.  If not found, returns
  2170.        *  npos.
  2171.       */
  2172.       size_type
  2173.       find_last_not_of(const _CharT* __s, size_type __pos = npos) const
  2174.       {
  2175.         __glibcxx_requires_string(__s);
  2176.         return this->find_last_not_of(__s, __pos, traits_type::length(__s));
  2177.       }
  2178.  
  2179.       /**
  2180.        *  @brief  Find last position of a different character.
  2181.        *  @param __c  Character to avoid.
  2182.        *  @param __pos  Index of character to search back from (default end).
  2183.        *  @return  Index of last occurrence.
  2184.        *
  2185.        *  Starting from @a __pos, searches backward for a character other than
  2186.        *  @a __c within this string.  If found, returns the index where it was
  2187.        *  found.  If not found, returns npos.
  2188.       */
  2189.       size_type
  2190.       find_last_not_of(_CharT __c, size_type __pos = npos) const
  2191.         _GLIBCXX_NOEXCEPT;
  2192.  
  2193.       /**
  2194.        *  @brief  Get a substring.
  2195.        *  @param __pos  Index of first character (default 0).
  2196.        *  @param __n  Number of characters in substring (default remainder).
  2197.        *  @return  The new string.
  2198.        *  @throw  std::out_of_range  If __pos > size().
  2199.        *
  2200.        *  Construct and return a new string using the @a __n
  2201.        *  characters starting at @a __pos.  If the string is too
  2202.        *  short, use the remainder of the characters.  If @a __pos is
  2203.        *  beyond the end of the string, out_of_range is thrown.
  2204.       */
  2205.       basic_string
  2206.       substr(size_type __pos = 0, size_type __n = npos) const
  2207.       { return basic_string(*this,
  2208.                             _M_check(__pos, "basic_string::substr"), __n); }
  2209.  
  2210.       /**
  2211.        *  @brief  Compare to a string.
  2212.        *  @param __str  String to compare against.
  2213.        *  @return  Integer < 0, 0, or > 0.
  2214.        *
  2215.        *  Returns an integer < 0 if this string is ordered before @a
  2216.        *  __str, 0 if their values are equivalent, or > 0 if this
  2217.        *  string is ordered after @a __str.  Determines the effective
  2218.        *  length rlen of the strings to compare as the smallest of
  2219.        *  size() and str.size().  The function then compares the two
  2220.        *  strings by calling traits::compare(data(), str.data(),rlen).
  2221.        *  If the result of the comparison is nonzero returns it,
  2222.        *  otherwise the shorter one is ordered first.
  2223.       */
  2224.       int
  2225.       compare(const basic_string& __str) const
  2226.       {
  2227.         const size_type __size = this->size();
  2228.         const size_type __osize = __str.size();
  2229.         const size_type __len = std::min(__size, __osize);
  2230.  
  2231.         int __r = traits_type::compare(_M_data(), __str.data(), __len);
  2232.         if (!__r)
  2233.           __r = _S_compare(__size, __osize);
  2234.         return __r;
  2235.       }
  2236.  
  2237.       /**
  2238.        *  @brief  Compare substring to a string.
  2239.        *  @param __pos  Index of first character of substring.
  2240.        *  @param __n  Number of characters in substring.
  2241.        *  @param __str  String to compare against.
  2242.        *  @return  Integer < 0, 0, or > 0.
  2243.        *
  2244.        *  Form the substring of this string from the @a __n characters
  2245.        *  starting at @a __pos.  Returns an integer < 0 if the
  2246.        *  substring is ordered before @a __str, 0 if their values are
  2247.        *  equivalent, or > 0 if the substring is ordered after @a
  2248.        *  __str.  Determines the effective length rlen of the strings
  2249.        *  to compare as the smallest of the length of the substring
  2250.        *  and @a __str.size().  The function then compares the two
  2251.        *  strings by calling
  2252.        *  traits::compare(substring.data(),str.data(),rlen).  If the
  2253.        *  result of the comparison is nonzero returns it, otherwise
  2254.        *  the shorter one is ordered first.
  2255.       */
  2256.       int
  2257.       compare(size_type __pos, size_type __n, const basic_string& __str) const;
  2258.  
  2259.       /**
  2260.        *  @brief  Compare substring to a substring.
  2261.        *  @param __pos1  Index of first character of substring.
  2262.        *  @param __n1  Number of characters in substring.
  2263.        *  @param __str  String to compare against.
  2264.        *  @param __pos2  Index of first character of substring of str.
  2265.        *  @param __n2  Number of characters in substring of str.
  2266.        *  @return  Integer < 0, 0, or > 0.
  2267.        *
  2268.        *  Form the substring of this string from the @a __n1
  2269.        *  characters starting at @a __pos1.  Form the substring of @a
  2270.        *  __str from the @a __n2 characters starting at @a __pos2.
  2271.        *  Returns an integer < 0 if this substring is ordered before
  2272.        *  the substring of @a __str, 0 if their values are equivalent,
  2273.        *  or > 0 if this substring is ordered after the substring of
  2274.        *  @a __str.  Determines the effective length rlen of the
  2275.        *  strings to compare as the smallest of the lengths of the
  2276.        *  substrings.  The function then compares the two strings by
  2277.        *  calling
  2278.        *  traits::compare(substring.data(),str.substr(pos2,n2).data(),rlen).
  2279.        *  If the result of the comparison is nonzero returns it,
  2280.        *  otherwise the shorter one is ordered first.
  2281.       */
  2282.       int
  2283.       compare(size_type __pos1, size_type __n1, const basic_string& __str,
  2284.               size_type __pos2, size_type __n2) const;
  2285.  
  2286.       /**
  2287.        *  @brief  Compare to a C string.
  2288.        *  @param __s  C string to compare against.
  2289.        *  @return  Integer < 0, 0, or > 0.
  2290.        *
  2291.        *  Returns an integer < 0 if this string is ordered before @a __s, 0 if
  2292.        *  their values are equivalent, or > 0 if this string is ordered after
  2293.        *  @a __s.  Determines the effective length rlen of the strings to
  2294.        *  compare as the smallest of size() and the length of a string
  2295.        *  constructed from @a __s.  The function then compares the two strings
  2296.        *  by calling traits::compare(data(),s,rlen).  If the result of the
  2297.        *  comparison is nonzero returns it, otherwise the shorter one is
  2298.        *  ordered first.
  2299.       */
  2300.       int
  2301.       compare(const _CharT* __s) const;
  2302.  
  2303.       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  2304.       // 5 String::compare specification questionable
  2305.       /**
  2306.        *  @brief  Compare substring to a C string.
  2307.        *  @param __pos  Index of first character of substring.
  2308.        *  @param __n1  Number of characters in substring.
  2309.        *  @param __s  C string to compare against.
  2310.        *  @return  Integer < 0, 0, or > 0.
  2311.        *
  2312.        *  Form the substring of this string from the @a __n1
  2313.        *  characters starting at @a pos.  Returns an integer < 0 if
  2314.        *  the substring is ordered before @a __s, 0 if their values
  2315.        *  are equivalent, or > 0 if the substring is ordered after @a
  2316.        *  __s.  Determines the effective length rlen of the strings to
  2317.        *  compare as the smallest of the length of the substring and
  2318.        *  the length of a string constructed from @a __s.  The
  2319.        *  function then compares the two string by calling
  2320.        *  traits::compare(substring.data(),__s,rlen).  If the result of
  2321.        *  the comparison is nonzero returns it, otherwise the shorter
  2322.        *  one is ordered first.
  2323.       */
  2324.       int
  2325.       compare(size_type __pos, size_type __n1, const _CharT* __s) const;
  2326.  
  2327.       /**
  2328.        *  @brief  Compare substring against a character %array.
  2329.        *  @param __pos  Index of first character of substring.
  2330.        *  @param __n1  Number of characters in substring.
  2331.        *  @param __s  character %array to compare against.
  2332.        *  @param __n2  Number of characters of s.
  2333.        *  @return  Integer < 0, 0, or > 0.
  2334.        *
  2335.        *  Form the substring of this string from the @a __n1
  2336.        *  characters starting at @a __pos.  Form a string from the
  2337.        *  first @a __n2 characters of @a __s.  Returns an integer < 0
  2338.        *  if this substring is ordered before the string from @a __s,
  2339.        *  0 if their values are equivalent, or > 0 if this substring
  2340.        *  is ordered after the string from @a __s.  Determines the
  2341.        *  effective length rlen of the strings to compare as the
  2342.        *  smallest of the length of the substring and @a __n2.  The
  2343.        *  function then compares the two strings by calling
  2344.        *  traits::compare(substring.data(),s,rlen).  If the result of
  2345.        *  the comparison is nonzero returns it, otherwise the shorter
  2346.        *  one is ordered first.
  2347.        *
  2348.        *  NB: s must have at least n2 characters, &apos;\\0&apos; has
  2349.        *  no special meaning.
  2350.       */
  2351.       int
  2352.       compare(size_type __pos, size_type __n1, const _CharT* __s,
  2353.               size_type __n2) const;
  2354.   };
  2355.  
  2356.   // operator+
  2357.   /**
  2358.    *  @brief  Concatenate two strings.
  2359.    *  @param __lhs  First string.
  2360.    *  @param __rhs  Last string.
  2361.    *  @return  New string with value of @a __lhs followed by @a __rhs.
  2362.    */
  2363.   template<typename _CharT, typename _Traits, typename _Alloc>
  2364.     basic_string<_CharT, _Traits, _Alloc>
  2365.     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2366.               const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2367.     {
  2368.       basic_string<_CharT, _Traits, _Alloc> __str(__lhs);
  2369.       __str.append(__rhs);
  2370.       return __str;
  2371.     }
  2372.  
  2373.   /**
  2374.    *  @brief  Concatenate C string and string.
  2375.    *  @param __lhs  First string.
  2376.    *  @param __rhs  Last string.
  2377.    *  @return  New string with value of @a __lhs followed by @a __rhs.
  2378.    */
  2379.   template<typename _CharT, typename _Traits, typename _Alloc>
  2380.     basic_string<_CharT,_Traits,_Alloc>
  2381.     operator+(const _CharT* __lhs,
  2382.               const basic_string<_CharT,_Traits,_Alloc>& __rhs);
  2383.  
  2384.   /**
  2385.    *  @brief  Concatenate character and string.
  2386.    *  @param __lhs  First string.
  2387.    *  @param __rhs  Last string.
  2388.    *  @return  New string with @a __lhs followed by @a __rhs.
  2389.    */
  2390.   template<typename _CharT, typename _Traits, typename _Alloc>
  2391.     basic_string<_CharT,_Traits,_Alloc>
  2392.     operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs);
  2393.  
  2394.   /**
  2395.    *  @brief  Concatenate string and C string.
  2396.    *  @param __lhs  First string.
  2397.    *  @param __rhs  Last string.
  2398.    *  @return  New string with @a __lhs followed by @a __rhs.
  2399.    */
  2400.   template<typename _CharT, typename _Traits, typename _Alloc>
  2401.     inline basic_string<_CharT, _Traits, _Alloc>
  2402.     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2403.              const _CharT* __rhs)
  2404.     {
  2405.       basic_string<_CharT, _Traits, _Alloc> __str(__lhs);
  2406.       __str.append(__rhs);
  2407.       return __str;
  2408.     }
  2409.  
  2410.   /**
  2411.    *  @brief  Concatenate string and character.
  2412.    *  @param __lhs  First string.
  2413.    *  @param __rhs  Last string.
  2414.    *  @return  New string with @a __lhs followed by @a __rhs.
  2415.    */
  2416.   template<typename _CharT, typename _Traits, typename _Alloc>
  2417.     inline basic_string<_CharT, _Traits, _Alloc>
  2418.     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs)
  2419.     {
  2420.       typedef basic_string<_CharT, _Traits, _Alloc>     __string_type;
  2421.       typedef typename __string_type::size_type         __size_type;
  2422.       __string_type __str(__lhs);
  2423.       __str.append(__size_type(1), __rhs);
  2424.       return __str;
  2425.     }
  2426.  
  2427. #if __cplusplus >= 201103L
  2428.   template<typename _CharT, typename _Traits, typename _Alloc>
  2429.     inline basic_string<_CharT, _Traits, _Alloc>
  2430.     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
  2431.               const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2432.     { return std::move(__lhs.append(__rhs)); }
  2433.  
  2434.   template<typename _CharT, typename _Traits, typename _Alloc>
  2435.     inline basic_string<_CharT, _Traits, _Alloc>
  2436.     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2437.               basic_string<_CharT, _Traits, _Alloc>&& __rhs)
  2438.     { return std::move(__rhs.insert(0, __lhs)); }
  2439.  
  2440.   template<typename _CharT, typename _Traits, typename _Alloc>
  2441.     inline basic_string<_CharT, _Traits, _Alloc>
  2442.     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
  2443.               basic_string<_CharT, _Traits, _Alloc>&& __rhs)
  2444.     {
  2445.       const auto __size = __lhs.size() + __rhs.size();
  2446.       const bool __cond = (__size > __lhs.capacity()
  2447.                            && __size <= __rhs.capacity());
  2448.       return __cond ? std::move(__rhs.insert(0, __lhs))
  2449.                     : std::move(__lhs.append(__rhs));
  2450.     }
  2451.  
  2452.   template<typename _CharT, typename _Traits, typename _Alloc>
  2453.     inline basic_string<_CharT, _Traits, _Alloc>
  2454.     operator+(const _CharT* __lhs,
  2455.               basic_string<_CharT, _Traits, _Alloc>&& __rhs)
  2456.     { return std::move(__rhs.insert(0, __lhs)); }
  2457.  
  2458.   template<typename _CharT, typename _Traits, typename _Alloc>
  2459.     inline basic_string<_CharT, _Traits, _Alloc>
  2460.     operator+(_CharT __lhs,
  2461.               basic_string<_CharT, _Traits, _Alloc>&& __rhs)
  2462.     { return std::move(__rhs.insert(0, 1, __lhs)); }
  2463.  
  2464.   template<typename _CharT, typename _Traits, typename _Alloc>
  2465.     inline basic_string<_CharT, _Traits, _Alloc>
  2466.     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
  2467.               const _CharT* __rhs)
  2468.     { return std::move(__lhs.append(__rhs)); }
  2469.  
  2470.   template<typename _CharT, typename _Traits, typename _Alloc>
  2471.     inline basic_string<_CharT, _Traits, _Alloc>
  2472.     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
  2473.               _CharT __rhs)
  2474.     { return std::move(__lhs.append(1, __rhs)); }
  2475. #endif
  2476.  
  2477.   // operator ==
  2478.   /**
  2479.    *  @brief  Test equivalence of two strings.
  2480.    *  @param __lhs  First string.
  2481.    *  @param __rhs  Second string.
  2482.    *  @return  True if @a __lhs.compare(@a __rhs) == 0.  False otherwise.
  2483.    */
  2484.   template<typename _CharT, typename _Traits, typename _Alloc>
  2485.     inline bool
  2486.     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2487.                const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2488.     { return __lhs.compare(__rhs) == 0; }
  2489.  
  2490.   template<typename _CharT>
  2491.     inline
  2492.     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, bool>::__type
  2493.     operator==(const basic_string<_CharT>& __lhs,
  2494.                const basic_string<_CharT>& __rhs)
  2495.     { return (__lhs.size() == __rhs.size()
  2496.               && !std::char_traits<_CharT>::compare(__lhs.data(), __rhs.data(),
  2497.                                                     __lhs.size())); }
  2498.  
  2499.   /**
  2500.    *  @brief  Test equivalence of C string and string.
  2501.    *  @param __lhs  C string.
  2502.    *  @param __rhs  String.
  2503.    *  @return  True if @a __rhs.compare(@a __lhs) == 0.  False otherwise.
  2504.    */
  2505.   template<typename _CharT, typename _Traits, typename _Alloc>
  2506.     inline bool
  2507.     operator==(const _CharT* __lhs,
  2508.                const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2509.     { return __rhs.compare(__lhs) == 0; }
  2510.  
  2511.   /**
  2512.    *  @brief  Test equivalence of string and C string.
  2513.    *  @param __lhs  String.
  2514.    *  @param __rhs  C string.
  2515.    *  @return  True if @a __lhs.compare(@a __rhs) == 0.  False otherwise.
  2516.    */
  2517.   template<typename _CharT, typename _Traits, typename _Alloc>
  2518.     inline bool
  2519.     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2520.                const _CharT* __rhs)
  2521.     { return __lhs.compare(__rhs) == 0; }
  2522.  
  2523.   // operator !=
  2524.   /**
  2525.    *  @brief  Test difference of two strings.
  2526.    *  @param __lhs  First string.
  2527.    *  @param __rhs  Second string.
  2528.    *  @return  True if @a __lhs.compare(@a __rhs) != 0.  False otherwise.
  2529.    */
  2530.   template<typename _CharT, typename _Traits, typename _Alloc>
  2531.     inline bool
  2532.     operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2533.                const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2534.     { return !(__lhs == __rhs); }
  2535.  
  2536.   /**
  2537.    *  @brief  Test difference of C string and string.
  2538.    *  @param __lhs  C string.
  2539.    *  @param __rhs  String.
  2540.    *  @return  True if @a __rhs.compare(@a __lhs) != 0.  False otherwise.
  2541.    */
  2542.   template<typename _CharT, typename _Traits, typename _Alloc>
  2543.     inline bool
  2544.     operator!=(const _CharT* __lhs,
  2545.                const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2546.     { return !(__lhs == __rhs); }
  2547.  
  2548.   /**
  2549.    *  @brief  Test difference of string and C string.
  2550.    *  @param __lhs  String.
  2551.    *  @param __rhs  C string.
  2552.    *  @return  True if @a __lhs.compare(@a __rhs) != 0.  False otherwise.
  2553.    */
  2554.   template<typename _CharT, typename _Traits, typename _Alloc>
  2555.     inline bool
  2556.     operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2557.                const _CharT* __rhs)
  2558.     { return !(__lhs == __rhs); }
  2559.  
  2560.   // operator <
  2561.   /**
  2562.    *  @brief  Test if string precedes string.
  2563.    *  @param __lhs  First string.
  2564.    *  @param __rhs  Second string.
  2565.    *  @return  True if @a __lhs precedes @a __rhs.  False otherwise.
  2566.    */
  2567.   template<typename _CharT, typename _Traits, typename _Alloc>
  2568.     inline bool
  2569.     operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2570.               const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2571.     { return __lhs.compare(__rhs) < 0; }
  2572.  
  2573.   /**
  2574.    *  @brief  Test if string precedes C string.
  2575.    *  @param __lhs  String.
  2576.    *  @param __rhs  C string.
  2577.    *  @return  True if @a __lhs precedes @a __rhs.  False otherwise.
  2578.    */
  2579.   template<typename _CharT, typename _Traits, typename _Alloc>
  2580.     inline bool
  2581.     operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2582.               const _CharT* __rhs)
  2583.     { return __lhs.compare(__rhs) < 0; }
  2584.  
  2585.   /**
  2586.    *  @brief  Test if C string precedes string.
  2587.    *  @param __lhs  C string.
  2588.    *  @param __rhs  String.
  2589.    *  @return  True if @a __lhs precedes @a __rhs.  False otherwise.
  2590.    */
  2591.   template<typename _CharT, typename _Traits, typename _Alloc>
  2592.     inline bool
  2593.     operator<(const _CharT* __lhs,
  2594.               const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2595.     { return __rhs.compare(__lhs) > 0; }
  2596.  
  2597.   // operator >
  2598.   /**
  2599.    *  @brief  Test if string follows string.
  2600.    *  @param __lhs  First string.
  2601.    *  @param __rhs  Second string.
  2602.    *  @return  True if @a __lhs follows @a __rhs.  False otherwise.
  2603.    */
  2604.   template<typename _CharT, typename _Traits, typename _Alloc>
  2605.     inline bool
  2606.     operator>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2607.               const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2608.     { return __lhs.compare(__rhs) > 0; }
  2609.  
  2610.   /**
  2611.    *  @brief  Test if string follows C string.
  2612.    *  @param __lhs  String.
  2613.    *  @param __rhs  C string.
  2614.    *  @return  True if @a __lhs follows @a __rhs.  False otherwise.
  2615.    */
  2616.   template<typename _CharT, typename _Traits, typename _Alloc>
  2617.     inline bool
  2618.     operator>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2619.               const _CharT* __rhs)
  2620.     { return __lhs.compare(__rhs) > 0; }
  2621.  
  2622.   /**
  2623.    *  @brief  Test if C string follows string.
  2624.    *  @param __lhs  C string.
  2625.    *  @param __rhs  String.
  2626.    *  @return  True if @a __lhs follows @a __rhs.  False otherwise.
  2627.    */
  2628.   template<typename _CharT, typename _Traits, typename _Alloc>
  2629.     inline bool
  2630.     operator>(const _CharT* __lhs,
  2631.               const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2632.     { return __rhs.compare(__lhs) < 0; }
  2633.  
  2634.   // operator <=
  2635.   /**
  2636.    *  @brief  Test if string doesn't follow string.
  2637.    *  @param __lhs  First string.
  2638.    *  @param __rhs  Second string.
  2639.    *  @return  True if @a __lhs doesn't follow @a __rhs.  False otherwise.
  2640.    */
  2641.   template<typename _CharT, typename _Traits, typename _Alloc>
  2642.     inline bool
  2643.     operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2644.                const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2645.     { return __lhs.compare(__rhs) <= 0; }
  2646.  
  2647.   /**
  2648.    *  @brief  Test if string doesn't follow C string.
  2649.    *  @param __lhs  String.
  2650.    *  @param __rhs  C string.
  2651.    *  @return  True if @a __lhs doesn't follow @a __rhs.  False otherwise.
  2652.    */
  2653.   template<typename _CharT, typename _Traits, typename _Alloc>
  2654.     inline bool
  2655.     operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2656.                const _CharT* __rhs)
  2657.     { return __lhs.compare(__rhs) <= 0; }
  2658.  
  2659.   /**
  2660.    *  @brief  Test if C string doesn't follow string.
  2661.    *  @param __lhs  C string.
  2662.    *  @param __rhs  String.
  2663.    *  @return  True if @a __lhs doesn't follow @a __rhs.  False otherwise.
  2664.    */
  2665.   template<typename _CharT, typename _Traits, typename _Alloc>
  2666.     inline bool
  2667.     operator<=(const _CharT* __lhs,
  2668.                const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2669.     { return __rhs.compare(__lhs) >= 0; }
  2670.  
  2671.   // operator >=
  2672.   /**
  2673.    *  @brief  Test if string doesn't precede string.
  2674.    *  @param __lhs  First string.
  2675.    *  @param __rhs  Second string.
  2676.    *  @return  True if @a __lhs doesn't precede @a __rhs.  False otherwise.
  2677.    */
  2678.   template<typename _CharT, typename _Traits, typename _Alloc>
  2679.     inline bool
  2680.     operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2681.                const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2682.     { return __lhs.compare(__rhs) >= 0; }
  2683.  
  2684.   /**
  2685.    *  @brief  Test if string doesn't precede C string.
  2686.    *  @param __lhs  String.
  2687.    *  @param __rhs  C string.
  2688.    *  @return  True if @a __lhs doesn't precede @a __rhs.  False otherwise.
  2689.    */
  2690.   template<typename _CharT, typename _Traits, typename _Alloc>
  2691.     inline bool
  2692.     operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2693.                const _CharT* __rhs)
  2694.     { return __lhs.compare(__rhs) >= 0; }
  2695.  
  2696.   /**
  2697.    *  @brief  Test if C string doesn't precede string.
  2698.    *  @param __lhs  C string.
  2699.    *  @param __rhs  String.
  2700.    *  @return  True if @a __lhs doesn't precede @a __rhs.  False otherwise.
  2701.    */
  2702.   template<typename _CharT, typename _Traits, typename _Alloc>
  2703.     inline bool
  2704.     operator>=(const _CharT* __lhs,
  2705.              const basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2706.     { return __rhs.compare(__lhs) <= 0; }
  2707.  
  2708.   /**
  2709.    *  @brief  Swap contents of two strings.
  2710.    *  @param __lhs  First string.
  2711.    *  @param __rhs  Second string.
  2712.    *
  2713.    *  Exchanges the contents of @a __lhs and @a __rhs in constant time.
  2714.    */
  2715.   template<typename _CharT, typename _Traits, typename _Alloc>
  2716.     inline void
  2717.     swap(basic_string<_CharT, _Traits, _Alloc>& __lhs,
  2718.          basic_string<_CharT, _Traits, _Alloc>& __rhs)
  2719.     { __lhs.swap(__rhs); }
  2720.  
  2721.   /**
  2722.    *  @brief  Read stream into a string.
  2723.    *  @param __is  Input stream.
  2724.    *  @param __str  Buffer to store into.
  2725.    *  @return  Reference to the input stream.
  2726.    *
  2727.    *  Stores characters from @a __is into @a __str until whitespace is
  2728.    *  found, the end of the stream is encountered, or str.max_size()
  2729.    *  is reached.  If is.width() is non-zero, that is the limit on the
  2730.    *  number of characters stored into @a __str.  Any previous
  2731.    *  contents of @a __str are erased.
  2732.    */
  2733.   template<typename _CharT, typename _Traits, typename _Alloc>
  2734.     basic_istream<_CharT, _Traits>&
  2735.     operator>>(basic_istream<_CharT, _Traits>& __is,
  2736.                basic_string<_CharT, _Traits, _Alloc>& __str);
  2737.  
  2738.   template<>
  2739.     basic_istream<char>&
  2740.     operator>>(basic_istream<char>& __is, basic_string<char>& __str);
  2741.  
  2742.   /**
  2743.    *  @brief  Write string to a stream.
  2744.    *  @param __os  Output stream.
  2745.    *  @param __str  String to write out.
  2746.    *  @return  Reference to the output stream.
  2747.    *
  2748.    *  Output characters of @a __str into os following the same rules as for
  2749.    *  writing a C string.
  2750.    */
  2751.   template<typename _CharT, typename _Traits, typename _Alloc>
  2752.     inline basic_ostream<_CharT, _Traits>&
  2753.     operator<<(basic_ostream<_CharT, _Traits>& __os,
  2754.                const basic_string<_CharT, _Traits, _Alloc>& __str)
  2755.     {
  2756.       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  2757.       // 586. string inserter not a formatted function
  2758.       return __ostream_insert(__os, __str.data(), __str.size());
  2759.     }
  2760.  
  2761.   /**
  2762.    *  @brief  Read a line from stream into a string.
  2763.    *  @param __is  Input stream.
  2764.    *  @param __str  Buffer to store into.
  2765.    *  @param __delim  Character marking end of line.
  2766.    *  @return  Reference to the input stream.
  2767.    *
  2768.    *  Stores characters from @a __is into @a __str until @a __delim is
  2769.    *  found, the end of the stream is encountered, or str.max_size()
  2770.    *  is reached.  Any previous contents of @a __str are erased.  If
  2771.    *  @a __delim is encountered, it is extracted but not stored into
  2772.    *  @a __str.
  2773.    */
  2774.   template<typename _CharT, typename _Traits, typename _Alloc>
  2775.     basic_istream<_CharT, _Traits>&
  2776.     getline(basic_istream<_CharT, _Traits>& __is,
  2777.             basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim);
  2778.  
  2779.   /**
  2780.    *  @brief  Read a line from stream into a string.
  2781.    *  @param __is  Input stream.
  2782.    *  @param __str  Buffer to store into.
  2783.    *  @return  Reference to the input stream.
  2784.    *
  2785.    *  Stores characters from is into @a __str until &apos;\n&apos; is
  2786.    *  found, the end of the stream is encountered, or str.max_size()
  2787.    *  is reached.  Any previous contents of @a __str are erased.  If
  2788.    *  end of line is encountered, it is extracted but not stored into
  2789.    *  @a __str.
  2790.    */
  2791.   template<typename _CharT, typename _Traits, typename _Alloc>
  2792.     inline basic_istream<_CharT, _Traits>&
  2793.     getline(basic_istream<_CharT, _Traits>& __is,
  2794.             basic_string<_CharT, _Traits, _Alloc>& __str)
  2795.     { return getline(__is, __str, __is.widen('\n')); }
  2796.  
  2797.   template<>
  2798.     basic_istream<char>&
  2799.     getline(basic_istream<char>& __in, basic_string<char>& __str,
  2800.             char __delim);
  2801.  
  2802. #ifdef _GLIBCXX_USE_WCHAR_T
  2803.   template<>
  2804.     basic_istream<wchar_t>&
  2805.     getline(basic_istream<wchar_t>& __in, basic_string<wchar_t>& __str,
  2806.             wchar_t __delim);
  2807. #endif  
  2808.  
  2809. _GLIBCXX_END_NAMESPACE_VERSION
  2810. } // namespace
  2811.  
  2812. #if ((__cplusplus >= 201103L) && defined(_GLIBCXX_USE_C99) \
  2813.      && !defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF))
  2814.  
  2815. #include <ext/string_conversions.h>
  2816.  
  2817. namespace std _GLIBCXX_VISIBILITY(default)
  2818. {
  2819. _GLIBCXX_BEGIN_NAMESPACE_VERSION
  2820.  
  2821.   // 21.4 Numeric Conversions [string.conversions].
  2822.   inline int
  2823.   stoi(const string& __str, size_t* __idx = 0, int __base = 10)
  2824.   { return __gnu_cxx::__stoa<long, int>(&std::strtol, "stoi", __str.c_str(),
  2825.                                         __idx, __base); }
  2826.  
  2827.   inline long
  2828.   stol(const string& __str, size_t* __idx = 0, int __base = 10)
  2829.   { return __gnu_cxx::__stoa(&std::strtol, "stol", __str.c_str(),
  2830.                              __idx, __base); }
  2831.  
  2832.   inline unsigned long
  2833.   stoul(const string& __str, size_t* __idx = 0, int __base = 10)
  2834.   { return __gnu_cxx::__stoa(&std::strtoul, "stoul", __str.c_str(),
  2835.                              __idx, __base); }
  2836.  
  2837.   inline long long
  2838.   stoll(const string& __str, size_t* __idx = 0, int __base = 10)
  2839.   { return __gnu_cxx::__stoa(&std::strtoll, "stoll", __str.c_str(),
  2840.                              __idx, __base); }
  2841.  
  2842.   inline unsigned long long
  2843.   stoull(const string& __str, size_t* __idx = 0, int __base = 10)
  2844.   { return __gnu_cxx::__stoa(&std::strtoull, "stoull", __str.c_str(),
  2845.                              __idx, __base); }
  2846.  
  2847.   // NB: strtof vs strtod.
  2848.   inline float
  2849.   stof(const string& __str, size_t* __idx = 0)
  2850.   { return __gnu_cxx::__stoa(&std::strtof, "stof", __str.c_str(), __idx); }
  2851.  
  2852.   inline double
  2853.   stod(const string& __str, size_t* __idx = 0)
  2854.   { return __gnu_cxx::__stoa(&std::strtod, "stod", __str.c_str(), __idx); }
  2855.  
  2856.   inline long double
  2857.   stold(const string& __str, size_t* __idx = 0)
  2858.   { return __gnu_cxx::__stoa(&std::strtold, "stold", __str.c_str(), __idx); }
  2859.  
  2860.   // NB: (v)snprintf vs sprintf.
  2861.  
  2862.   // DR 1261.
  2863.   inline string
  2864.   to_string(int __val)
  2865.   { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(int),
  2866.                                            "%d", __val); }
  2867.  
  2868.   inline string
  2869.   to_string(unsigned __val)
  2870.   { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
  2871.                                            4 * sizeof(unsigned),
  2872.                                            "%u", __val); }
  2873.  
  2874.   inline string
  2875.   to_string(long __val)
  2876.   { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(long),
  2877.                                            "%ld", __val); }
  2878.  
  2879.   inline string
  2880.   to_string(unsigned long __val)
  2881.   { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
  2882.                                            4 * sizeof(unsigned long),
  2883.                                            "%lu", __val); }
  2884.  
  2885.   inline string
  2886.   to_string(long long __val)
  2887.   { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
  2888.                                            4 * sizeof(long long),
  2889.                                            "%lld", __val); }
  2890.  
  2891.   inline string
  2892.   to_string(unsigned long long __val)
  2893.   { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
  2894.                                            4 * sizeof(unsigned long long),
  2895.                                            "%llu", __val); }
  2896.  
  2897.   inline string
  2898.   to_string(float __val)
  2899.   {
  2900.     const int __n =
  2901.       __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20;
  2902.     return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
  2903.                                            "%f", __val);
  2904.   }
  2905.  
  2906.   inline string
  2907.   to_string(double __val)
  2908.   {
  2909.     const int __n =
  2910.       __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20;
  2911.     return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
  2912.                                            "%f", __val);
  2913.   }
  2914.  
  2915.   inline string
  2916.   to_string(long double __val)
  2917.   {
  2918.     const int __n =
  2919.       __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20;
  2920.     return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
  2921.                                            "%Lf", __val);
  2922.   }
  2923.  
  2924. #ifdef _GLIBCXX_USE_WCHAR_T
  2925.   inline int
  2926.   stoi(const wstring& __str, size_t* __idx = 0, int __base = 10)
  2927.   { return __gnu_cxx::__stoa<long, int>(&std::wcstol, "stoi", __str.c_str(),
  2928.                                         __idx, __base); }
  2929.  
  2930.   inline long
  2931.   stol(const wstring& __str, size_t* __idx = 0, int __base = 10)
  2932.   { return __gnu_cxx::__stoa(&std::wcstol, "stol", __str.c_str(),
  2933.                              __idx, __base); }
  2934.  
  2935.   inline unsigned long
  2936.   stoul(const wstring& __str, size_t* __idx = 0, int __base = 10)
  2937.   { return __gnu_cxx::__stoa(&std::wcstoul, "stoul", __str.c_str(),
  2938.                              __idx, __base); }
  2939.  
  2940.   inline long long
  2941.   stoll(const wstring& __str, size_t* __idx = 0, int __base = 10)
  2942.   { return __gnu_cxx::__stoa(&std::wcstoll, "stoll", __str.c_str(),
  2943.                              __idx, __base); }
  2944.  
  2945.   inline unsigned long long
  2946.   stoull(const wstring& __str, size_t* __idx = 0, int __base = 10)
  2947.   { return __gnu_cxx::__stoa(&std::wcstoull, "stoull", __str.c_str(),
  2948.                              __idx, __base); }
  2949.  
  2950.   // NB: wcstof vs wcstod.
  2951.   inline float
  2952.   stof(const wstring& __str, size_t* __idx = 0)
  2953.   { return __gnu_cxx::__stoa(&std::wcstof, "stof", __str.c_str(), __idx); }
  2954.  
  2955.   inline double
  2956.   stod(const wstring& __str, size_t* __idx = 0)
  2957.   { return __gnu_cxx::__stoa(&std::wcstod, "stod", __str.c_str(), __idx); }
  2958.  
  2959.   inline long double
  2960.   stold(const wstring& __str, size_t* __idx = 0)
  2961.   { return __gnu_cxx::__stoa(&std::wcstold, "stold", __str.c_str(), __idx); }
  2962.  
  2963.   // DR 1261.
  2964.   inline wstring
  2965.   to_wstring(int __val)
  2966.   { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(int),
  2967.                                             L"%d", __val); }
  2968.  
  2969.   inline wstring
  2970.   to_wstring(unsigned __val)
  2971.   { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
  2972.                                             4 * sizeof(unsigned),
  2973.                                             L"%u", __val); }
  2974.  
  2975.   inline wstring
  2976.   to_wstring(long __val)
  2977.   { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(long),
  2978.                                             L"%ld", __val); }
  2979.  
  2980.   inline wstring
  2981.   to_wstring(unsigned long __val)
  2982.   { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
  2983.                                             4 * sizeof(unsigned long),
  2984.                                             L"%lu", __val); }
  2985.  
  2986.   inline wstring
  2987.   to_wstring(long long __val)
  2988.   { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
  2989.                                             4 * sizeof(long long),
  2990.                                             L"%lld", __val); }
  2991.  
  2992.   inline wstring
  2993.   to_wstring(unsigned long long __val)
  2994.   { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
  2995.                                             4 * sizeof(unsigned long long),
  2996.                                             L"%llu", __val); }
  2997.  
  2998.   inline wstring
  2999.   to_wstring(float __val)
  3000.   {
  3001.     const int __n =
  3002.       __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20;
  3003.     return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
  3004.                                             L"%f", __val);
  3005.   }
  3006.  
  3007.   inline wstring
  3008.   to_wstring(double __val)
  3009.   {
  3010.     const int __n =
  3011.       __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20;
  3012.     return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
  3013.                                             L"%f", __val);
  3014.   }
  3015.  
  3016.   inline wstring
  3017.   to_wstring(long double __val)
  3018.   {
  3019.     const int __n =
  3020.       __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20;
  3021.     return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
  3022.                                             L"%Lf", __val);
  3023.   }
  3024. #endif
  3025.  
  3026. _GLIBCXX_END_NAMESPACE_VERSION
  3027. } // namespace
  3028.  
  3029. #endif /* C++11 && _GLIBCXX_USE_C99 ... */
  3030.  
  3031. #if __cplusplus >= 201103L
  3032.  
  3033. #include <bits/functional_hash.h>
  3034.  
  3035. namespace std _GLIBCXX_VISIBILITY(default)
  3036. {
  3037. _GLIBCXX_BEGIN_NAMESPACE_VERSION
  3038.  
  3039.   // DR 1182.
  3040.  
  3041. #ifndef _GLIBCXX_COMPATIBILITY_CXX0X
  3042.   /// std::hash specialization for string.
  3043.   template<>
  3044.     struct hash<string>
  3045.     : public __hash_base<size_t, string>
  3046.     {
  3047.       size_t
  3048.       operator()(const string& __s) const noexcept
  3049.       { return std::_Hash_impl::hash(__s.data(), __s.length()); }
  3050.     };
  3051.  
  3052.   template<>
  3053.     struct __is_fast_hash<hash<string>> : std::false_type
  3054.     { };
  3055.  
  3056. #ifdef _GLIBCXX_USE_WCHAR_T
  3057.   /// std::hash specialization for wstring.
  3058.   template<>
  3059.     struct hash<wstring>
  3060.     : public __hash_base<size_t, wstring>
  3061.     {
  3062.       size_t
  3063.       operator()(const wstring& __s) const noexcept
  3064.       { return std::_Hash_impl::hash(__s.data(),
  3065.                                      __s.length() * sizeof(wchar_t)); }
  3066.     };
  3067.  
  3068.   template<>
  3069.     struct __is_fast_hash<hash<wstring>> : std::false_type
  3070.     { };
  3071. #endif
  3072. #endif /* _GLIBCXX_COMPATIBILITY_CXX0X */
  3073.  
  3074. #ifdef _GLIBCXX_USE_C99_STDINT_TR1
  3075.   /// std::hash specialization for u16string.
  3076.   template<>
  3077.     struct hash<u16string>
  3078.     : public __hash_base<size_t, u16string>
  3079.     {
  3080.       size_t
  3081.       operator()(const u16string& __s) const noexcept
  3082.       { return std::_Hash_impl::hash(__s.data(),
  3083.                                      __s.length() * sizeof(char16_t)); }
  3084.     };
  3085.  
  3086.   template<>
  3087.     struct __is_fast_hash<hash<u16string>> : std::false_type
  3088.     { };
  3089.  
  3090.   /// std::hash specialization for u32string.
  3091.   template<>
  3092.     struct hash<u32string>
  3093.     : public __hash_base<size_t, u32string>
  3094.     {
  3095.       size_t
  3096.       operator()(const u32string& __s) const noexcept
  3097.       { return std::_Hash_impl::hash(__s.data(),
  3098.                                      __s.length() * sizeof(char32_t)); }
  3099.     };
  3100.  
  3101.   template<>
  3102.     struct __is_fast_hash<hash<u32string>> : std::false_type
  3103.     { };
  3104. #endif
  3105.  
  3106. _GLIBCXX_END_NAMESPACE_VERSION
  3107. } // namespace
  3108.  
  3109. #endif // C++11
  3110.  
  3111. #endif /* _BASIC_STRING_H */
  3112.