// -*- C++ -*-

//===----------------------------------------------------------------------===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_SSTREAM

#define _LIBCPP_SSTREAM

// clang-format off

/*

    sstream synopsis [sstream.syn]

// Class template basic_stringbuf [stringbuf]

template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >

class basic_stringbuf

    : public basic_streambuf<charT, traits>

{

public:

    typedef charT                          char_type;

    typedef traits                         traits_type;

    typedef typename traits_type::int_type int_type;

    typedef typename traits_type::pos_type pos_type;

    typedef typename traits_type::off_type off_type;

    typedef Allocator                      allocator_type;

    // [stringbuf.cons] constructors:

    explicit basic_stringbuf(ios_base::openmode which = ios_base::in | ios_base::out); // before C++20

    basic_stringbuf() : basic_stringbuf(ios_base::in | ios_base::out) {}               // C++20

    explicit basic_stringbuf(ios_base::openmode which);                                // C++20

    explicit basic_stringbuf(const basic_string<char_type, traits_type, allocator_type>& s,

                             ios_base::openmode which = ios_base::in | ios_base::out);

    explicit basic_stringbuf(const allocator_type& a)

        : basic_stringbuf(ios_base::in | ios_base::out, a) {}                          // C++20

    basic_stringbuf(ios_base::openmode which, const allocator_type& a);                // C++20

    explicit basic_stringbuf(basic_string<char_type, traits_type, allocator_type>&& s,

                             ios_base::openmode which = ios_base::in | ios_base::out); // C++20

    template <class SAlloc>

    basic_stringbuf(const basic_string<char_type, traits_type, SAlloc>& s, const allocator_type& a)

        : basic_stringbuf(s, ios_base::in | ios_base::out, a) {}                       // C++20

    template <class SAlloc>

    basic_stringbuf(const basic_string<char_type, traits_type, SAlloc>& s,

                    ios_base::openmode which, const allocator_type& a);                // C++20

    template <class SAlloc>

    explicit basic_stringbuf(const basic_string<char_type, traits_type, SAlloc>& s,

                             ios_base::openmode which = ios_base::in | ios_base::out); // C++20

    basic_stringbuf(basic_stringbuf&& rhs);

    basic_stringbuf(basic_stringbuf&& rhs, const allocator_type& a);                   // C++20

    // [stringbuf.assign] Assign and swap:

    basic_stringbuf& operator=(basic_stringbuf&& rhs);

    void swap(basic_stringbuf& rhs) noexcept(see below);                               // conditionally noexcept since C++20

    // [stringbuf.members] Member functions:

    allocator_type get_allocator() const noexcept;                                     // C++20

    basic_string<char_type, traits_type, allocator_type> str() const;                  // before C++20

    basic_string<char_type, traits_type, allocator_type> str() const &;                // C++20

    template <class SAlloc>

    basic_string<char_type, traits_type, SAlloc> str(const SAlloc& sa) const;          // C++20

    basic_string<char_type, traits_type, allocator_type> str() &&;                     // C++20

    basic_string_view<char_type, traits_type> view() const noexcept;                   // C++20

    void str(const basic_string<char_type, traits_type, allocator_type>& s);

    template <class SAlloc>

    void str(const basic_string<char_type, traits_type, SAlloc>& s);                   // C++20

    void str(basic_string<char_type, traits_type, allocator_type>&& s);                // C++20

protected:

    // [stringbuf.virtuals] Overridden virtual functions:

    virtual int_type underflow();

    virtual int_type pbackfail(int_type c = traits_type::eof());

    virtual int_type overflow (int_type c = traits_type::eof());

    virtual basic_streambuf<char_type, traits_type>* setbuf(char_type*, streamsize);

    virtual pos_type seekoff(off_type off, ios_base::seekdir way,

                             ios_base::openmode which = ios_base::in | ios_base::out);

    virtual pos_type seekpos(pos_type sp,

                             ios_base::openmode which = ios_base::in | ios_base::out);

};

// [stringbuf.assign] non member swap

template <class charT, class traits, class Allocator>

void swap(basic_stringbuf<charT, traits, Allocator>& x,

          basic_stringbuf<charT, traits, Allocator>& y); // conditionally noexcept since C++20

typedef basic_stringbuf<char>    stringbuf;

typedef basic_stringbuf<wchar_t> wstringbuf;

// Class template basic_istringstream [istringstream]

template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >

class basic_istringstream

    : public basic_istream<charT, traits>

{

public:

    typedef charT                          char_type;

    typedef traits                         traits_type;

    typedef typename traits_type::int_type int_type;

    typedef typename traits_type::pos_type pos_type;

    typedef typename traits_type::off_type off_type;

    typedef Allocator                      allocator_type;

    // [istringstream.cons] Constructors:

    explicit basic_istringstream(ios_base::openmode which = ios_base::in);             // before C++20

    basic_istringstream() : basic_istringstream(ios_base::in) {}                       // C++20

    explicit basic_istringstream(ios_base::openmode which);                            // C++20

    explicit basic_istringstream(const basic_string<char_type, traits_type, allocator_type>& s,

                                 ios_base::openmode which = ios_base::in);

    basic_istringstream(ios_base::openmode which, const allocator_type& a);            // C++20

    explicit basic_istringstream(basic_string<char_type, traits_type, allocator_type>&& s,

                                 ios_base::openmode which = ios_base::in);             // C++20

    template <class SAlloc>

    basic_istringstream(const basic_string<char_type, traits_type, SAlloc>& s, const allocator_type& a)

        : basic_istringstream(s, ios_base::in, a) {}                                   // C++20

    template <class SAlloc>

    basic_istringstream(const basic_string<char_type, traits_type, SAlloc>& s,

                        ios_base::openmode which, const allocator_type& a);            // C++20

    template <class SAlloc>

    explicit basic_istringstream(const basic_string<char_type, traits_type, SAlloc>& s,

                                 ios_base::openmode which = ios_base::in);             // C++20

    basic_istringstream(basic_istringstream&& rhs);

    // [istringstream.assign] Assign and swap:

    basic_istringstream& operator=(basic_istringstream&& rhs);

    void swap(basic_istringstream& rhs);

    // [istringstream.members] Member functions:

    basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const;

    basic_string<char_type, traits_type, allocator_type> str() const;                  // before C++20

    basic_string<char_type, traits_type, allocator_type> str() const &;                // C++20

    template <class SAlloc>

    basic_string<char_type, traits_type, SAlloc> str(const SAlloc& sa) const;          // C++20

    basic_string<char_type, traits_type, allocator_type> str() &&;                     // C++20

    basic_string_view<char_type, traits_type> view() const noexcept;                   // C++20

    void str(const basic_string<char_type, traits_type, allocator_type>& s);

    template <class SAlloc>

    void str(const basic_string<char_type, traits_type, SAlloc>& s);                   // C++20

    void str(basic_string<char_type, traits_type, allocator_type>&& s);                // C++20

};

template <class charT, class traits, class Allocator>

void swap(basic_istringstream<charT, traits, Allocator>& x,

          basic_istringstream<charT, traits, Allocator>& y);

typedef basic_istringstream<char>    istringstream;

typedef basic_istringstream<wchar_t> wistringstream;

// Class template basic_ostringstream [ostringstream]

template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >

class basic_ostringstream

    : public basic_ostream<charT, traits>

{

public:

    // types:

    typedef charT                          char_type;

    typedef traits                         traits_type;

    typedef typename traits_type::int_type int_type;

    typedef typename traits_type::pos_type pos_type;

    typedef typename traits_type::off_type off_type;

    typedef Allocator                      allocator_type;

    // [ostringstream.cons] Constructors:

    explicit basic_ostringstream(ios_base::openmode which = ios_base::out);            // before C++20

    basic_ostringstream() : basic_ostringstream(ios_base::out) {}                      // C++20

    explicit basic_ostringstream(ios_base::openmode which);                            // C++20

    explicit basic_ostringstream(const basic_string<char_type, traits_type, allocator_type>& s,

                                 ios_base::openmode which = ios_base::out);

    basic_ostringstream(ios_base::openmode which, const allocator_type& a);            // C++20

    explicit basic_ostringstream(basic_string<char_type, traits_type, allocator_type>&& s,

                                 ios_base::openmode which = ios_base::out);            // C++20

    template <class SAlloc>

    basic_ostringstream(const basic_string<char_type, traits_type, SAlloc>& s, const allocator_type& a)

        : basic_ostringstream(s, ios_base::out, a) {}                                  // C++20

    template <class SAlloc>

    basic_ostringstream(const basic_string<char_type, traits_type, SAlloc>& s,

                        ios_base::openmode which, const allocator_type& a);            // C++20

    template <class SAlloc>

    explicit basic_ostringstream(const basic_string<char_type, traits_type, SAlloc>& s,

                                 ios_base::openmode which = ios_base::out);            // C++20

    basic_ostringstream(basic_ostringstream&& rhs);

    // [ostringstream.assign] Assign and swap:

    basic_ostringstream& operator=(basic_ostringstream&& rhs);

    void swap(basic_ostringstream& rhs);

    // [ostringstream.members] Member functions:

    basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const;

    basic_string<char_type, traits_type, allocator_type> str() const;                  // before C++20

    basic_string<char_type, traits_type, allocator_type> str() const &;                // C++20

    template <class SAlloc>

    basic_string<char_type, traits_type, SAlloc> str(const SAlloc& sa) const;          // C++20

    basic_string<char_type, traits_type, allocator_type> str() &&;                     // C++20

    basic_string_view<char_type, traits_type> view() const noexcept;                   // C++20

    void str(const basic_string<char_type, traits_type, allocator_type>& s);

    template <class SAlloc>

    void str(const basic_string<char_type, traits_type, SAlloc>& s);                   // C++20

    void str(basic_string<char_type, traits_type, allocator_type>&& s);                // C++20

};

template <class charT, class traits, class Allocator>

void swap(basic_ostringstream<charT, traits, Allocator>& x,

          basic_ostringstream<charT, traits, Allocator>& y);

typedef basic_ostringstream<char>    ostringstream;

typedef basic_ostringstream<wchar_t> wostringstream;

// Class template basic_stringstream [stringstream]

template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >

class basic_stringstream

    : public basic_iostream<charT, traits>

{

public:

    // types:

    typedef charT                          char_type;

    typedef traits                         traits_type;

    typedef typename traits_type::int_type int_type;

    typedef typename traits_type::pos_type pos_type;

    typedef typename traits_type::off_type off_type;

    typedef Allocator                      allocator_type;

    // [stringstream.cons] constructors

    explicit basic_stringstream(ios_base::openmode which = ios_base::out | ios_base::in); // before C++20

    basic_stringstream() : basic_stringstream(ios_base::out | ios_base::in) {}            // C++20

    explicit basic_stringstream(ios_base::openmode which);                                // C++20

    explicit basic_stringstream(const basic_string<char_type, traits_type, allocator_type>& s,

                                ios_base::openmode which = ios_base::out | ios_base::in);

    basic_stringstream(ios_base::openmode which, const allocator_type& a);                // C++20

    explicit basic_stringstream(basic_string<char_type, traits_type, allocator_type>&& s,

                                ios_base::openmode which = ios_base::out | ios_base::in); // C++20

    template <class SAlloc>

    basic_stringstream(const basic_string<char_type, traits_type, SAlloc>& s, const allocator_type& a)

        : basic_stringstream(s, ios_base::out | ios_base::in, a) {}                       // C++20

    template <class SAlloc>

    basic_stringstream(const basic_string<char_type, traits_type, SAlloc>& s,

                       ios_base::openmode which, const allocator_type& a);                // C++20

    template <class SAlloc>

    explicit basic_stringstream(const basic_string<char_type, traits_type, SAlloc>& s,

                                ios_base::openmode which = ios_base::out | ios_base::in); // C++20

    basic_stringstream(basic_stringstream&& rhs);

    // [stringstream.assign] Assign and swap:

    basic_stringstream& operator=(basic_stringstream&& rhs);

    void swap(basic_stringstream& rhs);

    // [stringstream.members] Member functions:

    basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const;

    basic_string<char_type, traits_type, allocator_type> str() const;                     // before C++20

    basic_string<char_type, traits_type, allocator_type> str() const &;                   // C++20

    template <class SAlloc>

    basic_string<char_type, traits_type, SAlloc> str(const SAlloc& sa) const;             // C++20

    basic_string<char_type, traits_type, allocator_type> str() &&;                        // C++20

    basic_string_view<char_type, traits_type> view() const noexcept;                      // C++20

    void str(const basic_string<char_type, traits_type, allocator_type>& s);

    template <class SAlloc>

    void str(const basic_string<char_type, traits_type, SAlloc>& s);                      // C++20

    void str(basic_string<char_type, traits_type, allocator_type>&& s);                   // C++20

};

template <class charT, class traits, class Allocator>

void swap(basic_stringstream<charT, traits, Allocator>& x,

          basic_stringstream<charT, traits, Allocator>& y);

typedef basic_stringstream<char>    stringstream;

typedef basic_stringstream<wchar_t> wstringstream;

}  // std

*/

// clang-format on

#include <__assert> // all public C++ headers provide the assertion handler

#include <__availability>

#include <__config>

#include <__fwd/sstream.h>

#include <__utility/swap.h>

#include <istream>

#include <ostream>

#include <string>

#include <version>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

#  pragma GCC system_header

#endif

_LIBCPP_PUSH_MACROS

#include <__undef_macros>

// TODO(LLVM-19): Remove this once we drop support for Clang 16,

// which had this bug: https://github.com/llvm/llvm-project/issues/40363

#ifdef _WIN32

#  define _LIBCPP_HIDE_FROM_ABI_SSTREAM _LIBCPP_ALWAYS_INLINE

#else

#  define _LIBCPP_HIDE_FROM_ABI_SSTREAM _LIBCPP_HIDE_FROM_ABI

#endif

_LIBCPP_BEGIN_NAMESPACE_STD

// Class template basic_stringbuf [stringbuf]

template <class _CharT, class _Traits, class _Allocator>

class _LIBCPP_TEMPLATE_VIS basic_stringbuf : public basic_streambuf<_CharT, _Traits> {

public:

  typedef _CharT char_type;

  typedef _Traits traits_type;

  typedef typename traits_type::int_type int_type;

  typedef typename traits_type::pos_type pos_type;

  typedef typename traits_type::off_type off_type;

  typedef _Allocator allocator_type;

  typedef basic_string<char_type, traits_type, allocator_type> string_type;

private:

  string_type __str_;

  mutable char_type* __hm_;

  ios_base::openmode __mode_;

  _LIBCPP_HIDE_FROM_ABI void __init_buf_ptrs();

  _LIBCPP_HIDE_FROM_ABI void __move_init(basic_stringbuf&& __rhs);

public:

  // [stringbuf.cons] constructors:

  _LIBCPP_HIDE_FROM_ABI basic_stringbuf() : __hm_(nullptr), __mode_(ios_base::in | ios_base::out) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_stringbuf(ios_base::openmode __wch) : __hm_(nullptr), __mode_(__wch) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_stringbuf(const string_type& __s,

                                                 ios_base::openmode __wch = ios_base::in | ios_base::out)

      : __str_(__s.get_allocator()), __hm_(nullptr), __mode_(__wch) {

    str(__s);

  }

#if _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI explicit basic_stringbuf(const allocator_type& __a)

      : basic_stringbuf(ios_base::in | ios_base::out, __a) {}

  _LIBCPP_HIDE_FROM_ABI basic_stringbuf(ios_base::openmode __wch, const allocator_type& __a)

      : __str_(__a), __hm_(nullptr), __mode_(__wch) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_stringbuf(string_type&& __s,

                                                 ios_base::openmode __wch = ios_base::in | ios_base::out)

      : __str_(std::move(__s)), __hm_(nullptr), __mode_(__wch) {

    __init_buf_ptrs();

  }

  template <class _SAlloc>

  _LIBCPP_HIDE_FROM_ABI

  basic_stringbuf(const basic_string<char_type, traits_type, _SAlloc>& __s, const allocator_type& __a)

      : basic_stringbuf(__s, ios_base::in | ios_base::out, __a) {}

  template <class _SAlloc>

  _LIBCPP_HIDE_FROM_ABI basic_stringbuf(

      const basic_string<char_type, traits_type, _SAlloc>& __s, ios_base::openmode __wch, const allocator_type& __a)

      : __str_(__s, __a), __hm_(nullptr), __mode_(__wch) {

    __init_buf_ptrs();

  }

  template <class _SAlloc>

    requires(!is_same_v<_SAlloc, allocator_type>)

  _LIBCPP_HIDE_FROM_ABI explicit basic_stringbuf(const basic_string<char_type, traits_type, _SAlloc>& __s,

                                                 ios_base::openmode __wch = ios_base::in | ios_base::out)

      : __str_(__s), __hm_(nullptr), __mode_(__wch) {

    __init_buf_ptrs();

  }

#endif // _LIBCPP_STD_VER >= 20

  basic_stringbuf(basic_stringbuf&& __rhs) : __mode_(__rhs.__mode_) { __move_init(std::move(__rhs)); }

#if _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI basic_stringbuf(basic_stringbuf&& __rhs, const allocator_type& __a)

      : basic_stringbuf(__rhs.__mode_, __a) {

    __move_init(std::move(__rhs));

  }

#endif

  // [stringbuf.assign] Assign and swap:

  basic_stringbuf& operator=(basic_stringbuf&& __rhs);

  void swap(basic_stringbuf& __rhs)

#if _LIBCPP_STD_VER >= 20

      noexcept(allocator_traits<allocator_type>::propagate_on_container_swap::value ||

               allocator_traits<allocator_type>::is_always_equal::value)

#endif

          ;

  // [stringbuf.members] Member functions:

#if _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const noexcept { return __str_.get_allocator(); }

#endif

#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_BUILDING_LIBRARY)

  string_type str() const;

#else

  _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() const& { return str(__str_.get_allocator()); }

  _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() && {

    const basic_string_view<_CharT, _Traits> __view = view();

    typename string_type::size_type __pos           = __view.empty() ? 0 : __view.data() - __str_.data();

    // In C++23, this is just string_type(std::move(__str_), __pos, __view.size(), __str_.get_allocator());

    // But we need something that works in C++20 also.

    string_type __result(std::move(__str_), __str_.get_allocator());

    __result.resize(__pos + __view.size());

    __result.erase(0, __pos);

    __init_buf_ptrs();

    return __result;

  }

#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_BUILDING_LIBRARY)

#if _LIBCPP_STD_VER >= 20

  template <class _SAlloc>

    requires __is_allocator<_SAlloc>::value

  _LIBCPP_HIDE_FROM_ABI basic_string<char_type, traits_type, _SAlloc> str(const _SAlloc& __sa) const {

    return basic_string<_CharT, _Traits, _SAlloc>(view(), __sa);

  }

  _LIBCPP_HIDE_FROM_ABI basic_string_view<char_type, traits_type> view() const noexcept;

#endif // _LIBCPP_STD_VER >= 20

  void str(const string_type& __s) {

    __str_ = __s;

    __init_buf_ptrs();

  }

#if _LIBCPP_STD_VER >= 20

  template <class _SAlloc>

    requires(!is_same_v<_SAlloc, allocator_type>)

  _LIBCPP_HIDE_FROM_ABI void str(const basic_string<char_type, traits_type, _SAlloc>& __s) {

    __str_ = __s;

    __init_buf_ptrs();

  }

  _LIBCPP_HIDE_FROM_ABI void str(string_type&& __s) {

    __str_ = std::move(__s);

    __init_buf_ptrs();

  }

#endif // _LIBCPP_STD_VER >= 20

protected:

  // [stringbuf.virtuals] Overridden virtual functions:

  int_type underflow() override;

  int_type pbackfail(int_type __c = traits_type::eof()) override;

  int_type overflow(int_type __c = traits_type::eof()) override;

  pos_type

  seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __wch = ios_base::in | ios_base::out) override;

  _LIBCPP_HIDE_FROM_ABI_VIRTUAL

  pos_type seekpos(pos_type __sp, ios_base::openmode __wch = ios_base::in | ios_base::out) override {

    return seekoff(__sp, ios_base::beg, __wch);

  }

};

template <class _CharT, class _Traits, class _Allocator>

_LIBCPP_HIDE_FROM_ABI void basic_stringbuf<_CharT, _Traits, _Allocator>::__move_init(basic_stringbuf&& __rhs) {

  char_type* __p   = const_cast<char_type*>(__rhs.__str_.data());

  ptrdiff_t __binp = -1;

  ptrdiff_t __ninp = -1;

  ptrdiff_t __einp = -1;

  if (__rhs.eback() != nullptr) {

    __binp = __rhs.eback() - __p;

    __ninp = __rhs.gptr() - __p;

    __einp = __rhs.egptr() - __p;

  }

  ptrdiff_t __bout = -1;

  ptrdiff_t __nout = -1;

  ptrdiff_t __eout = -1;

  if (__rhs.pbase() != nullptr) {

    __bout = __rhs.pbase() - __p;

    __nout = __rhs.pptr() - __p;

    __eout = __rhs.epptr() - __p;

  }

  ptrdiff_t __hm = __rhs.__hm_ == nullptr ? -1 : __rhs.__hm_ - __p;

  __str_         = std::move(__rhs.__str_);

  __p            = const_cast<char_type*>(__str_.data());

  if (__binp != -1)

    this->setg(__p + __binp, __p + __ninp, __p + __einp);

  if (__bout != -1) {

    this->setp(__p + __bout, __p + __eout);

    this->__pbump(__nout);

  }

  __hm_ = __hm == -1 ? nullptr : __p + __hm;

  __p   = const_cast<char_type*>(__rhs.__str_.data());

  __rhs.setg(__p, __p, __p);

  __rhs.setp(__p, __p);

  __rhs.__hm_ = __p;

  this->pubimbue(__rhs.getloc());

}

template <class _CharT, class _Traits, class _Allocator>

basic_stringbuf<_CharT, _Traits, _Allocator>&

basic_stringbuf<_CharT, _Traits, _Allocator>::operator=(basic_stringbuf&& __rhs) {

  char_type* __p   = const_cast<char_type*>(__rhs.__str_.data());

  ptrdiff_t __binp = -1;

  ptrdiff_t __ninp = -1;

  ptrdiff_t __einp = -1;

  if (__rhs.eback() != nullptr) {

    __binp = __rhs.eback() - __p;

    __ninp = __rhs.gptr() - __p;

    __einp = __rhs.egptr() - __p;

  }

  ptrdiff_t __bout = -1;

  ptrdiff_t __nout = -1;

  ptrdiff_t __eout = -1;

  if (__rhs.pbase() != nullptr) {

    __bout = __rhs.pbase() - __p;

    __nout = __rhs.pptr() - __p;

    __eout = __rhs.epptr() - __p;

  }

  ptrdiff_t __hm = __rhs.__hm_ == nullptr ? -1 : __rhs.__hm_ - __p;

  __str_         = std::move(__rhs.__str_);

  __p            = const_cast<char_type*>(__str_.data());

  if (__binp != -1)

    this->setg(__p + __binp, __p + __ninp, __p + __einp);

  else

    this->setg(nullptr, nullptr, nullptr);

  if (__bout != -1) {

    this->setp(__p + __bout, __p + __eout);

    this->__pbump(__nout);

  } else

    this->setp(nullptr, nullptr);

  __hm_   = __hm == -1 ? nullptr : __p + __hm;

  __mode_ = __rhs.__mode_;

  __p     = const_cast<char_type*>(__rhs.__str_.data());

  __rhs.setg(__p, __p, __p);

  __rhs.setp(__p, __p);

  __rhs.__hm_ = __p;

  this->pubimbue(__rhs.getloc());

  return *this;

}

template <class _CharT, class _Traits, class _Allocator>

void basic_stringbuf<_CharT, _Traits, _Allocator>::swap(basic_stringbuf& __rhs)

#if _LIBCPP_STD_VER >= 20

    noexcept(allocator_traits<_Allocator>::propagate_on_container_swap::value ||

             allocator_traits<_Allocator>::is_always_equal::value)

#endif

{

  char_type* __p    = const_cast<char_type*>(__rhs.__str_.data());

  ptrdiff_t __rbinp = -1;

  ptrdiff_t __rninp = -1;

  ptrdiff_t __reinp = -1;

  if (__rhs.eback() != nullptr) {

    __rbinp = __rhs.eback() - __p;

    __rninp = __rhs.gptr() - __p;

    __reinp = __rhs.egptr() - __p;

  }

  ptrdiff_t __rbout = -1;

  ptrdiff_t __rnout = -1;

  ptrdiff_t __reout = -1;

  if (__rhs.pbase() != nullptr) {

    __rbout = __rhs.pbase() - __p;

    __rnout = __rhs.pptr() - __p;

    __reout = __rhs.epptr() - __p;

  }

  ptrdiff_t __rhm   = __rhs.__hm_ == nullptr ? -1 : __rhs.__hm_ - __p;

  __p               = const_cast<char_type*>(__str_.data());

  ptrdiff_t __lbinp = -1;

  ptrdiff_t __lninp = -1;

  ptrdiff_t __leinp = -1;

  if (this->eback() != nullptr) {

    __lbinp = this->eback() - __p;

    __lninp = this->gptr() - __p;

    __leinp = this->egptr() - __p;

  }

  ptrdiff_t __lbout = -1;

  ptrdiff_t __lnout = -1;

  ptrdiff_t __leout = -1;

  if (this->pbase() != nullptr) {

    __lbout = this->pbase() - __p;

    __lnout = this->pptr() - __p;

    __leout = this->epptr() - __p;

  }

  ptrdiff_t __lhm = __hm_ == nullptr ? -1 : __hm_ - __p;

  std::swap(__mode_, __rhs.__mode_);

  __str_.swap(__rhs.__str_);

  __p = const_cast<char_type*>(__str_.data());

  if (__rbinp != -1)

    this->setg(__p + __rbinp, __p + __rninp, __p + __reinp);

  else

    this->setg(nullptr, nullptr, nullptr);

  if (__rbout != -1) {

    this->setp(__p + __rbout, __p + __reout);

    this->__pbump(__rnout);

  } else

    this->setp(nullptr, nullptr);

  __hm_ = __rhm == -1 ? nullptr : __p + __rhm;

  __p   = const_cast<char_type*>(__rhs.__str_.data());

  if (__lbinp != -1)

    __rhs.setg(__p + __lbinp, __p + __lninp, __p + __leinp);

  else

    __rhs.setg(nullptr, nullptr, nullptr);

  if (__lbout != -1) {

    __rhs.setp(__p + __lbout, __p + __leout);

    __rhs.__pbump(__lnout);

  } else

    __rhs.setp(nullptr, nullptr);

  __rhs.__hm_ = __lhm == -1 ? nullptr : __p + __lhm;

  locale __tl = __rhs.getloc();

  __rhs.pubimbue(this->getloc());

  this->pubimbue(__tl);

}

template <class _CharT, class _Traits, class _Allocator>

inline _LIBCPP_HIDE_FROM_ABI void

swap(basic_stringbuf<_CharT, _Traits, _Allocator>& __x, basic_stringbuf<_CharT, _Traits, _Allocator>& __y)

#if _LIBCPP_STD_VER >= 20

    noexcept(noexcept(__x.swap(__y)))

#endif

{

  __x.swap(__y);

}

#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_BUILDING_LIBRARY)

template <class _CharT, class _Traits, class _Allocator>

basic_string<_CharT, _Traits, _Allocator> basic_stringbuf<_CharT, _Traits, _Allocator>::str() const {

  if (__mode_ & ios_base::out) {

    if (__hm_ < this->pptr())

      __hm_ = this->pptr();

    return string_type(this->pbase(), __hm_, __str_.get_allocator());

  } else if (__mode_ & ios_base::in)

    return string_type(this->eback(), this->egptr(), __str_.get_allocator());

  return string_type(__str_.get_allocator());

}

#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_BUILDING_LIBRARY)

template <class _CharT, class _Traits, class _Allocator>

_LIBCPP_HIDE_FROM_ABI void basic_stringbuf<_CharT, _Traits, _Allocator>::__init_buf_ptrs() {

  __hm_                                = nullptr;

  char_type* __data                    = const_cast<char_type*>(__str_.data());

  typename string_type::size_type __sz = __str_.size();

  if (__mode_ & ios_base::in) {

    __hm_ = __data + __sz;

    this->setg(__data, __data, __hm_);

  }

  if (__mode_ & ios_base::out) {

    __hm_ = __data + __sz;

    __str_.resize(__str_.capacity());

    this->setp(__data, __data + __str_.size());

    if (__mode_ & (ios_base::app | ios_base::ate)) {

      while (__sz > INT_MAX) {

        this->pbump(INT_MAX);

        __sz -= INT_MAX;

      }

      if (__sz > 0)

        this->pbump(__sz);

    }

  }

}

#if _LIBCPP_STD_VER >= 20

template <class _CharT, class _Traits, class _Allocator>

_LIBCPP_HIDE_FROM_ABI basic_string_view<_CharT, _Traits>

basic_stringbuf<_CharT, _Traits, _Allocator>::view() const noexcept {

  if (__mode_ & ios_base::out) {

    if (__hm_ < this->pptr())

      __hm_ = this->pptr();

    return basic_string_view<_CharT, _Traits>(this->pbase(), __hm_);

  } else if (__mode_ & ios_base::in)

    return basic_string_view<_CharT, _Traits>(this->eback(), this->egptr());

  return basic_string_view<_CharT, _Traits>();

}

#endif // _LIBCPP_STD_VER >= 20

template <class _CharT, class _Traits, class _Allocator>

typename basic_stringbuf<_CharT, _Traits, _Allocator>::int_type

basic_stringbuf<_CharT, _Traits, _Allocator>::underflow() {

  if (__hm_ < this->pptr())

    __hm_ = this->pptr();

  if (__mode_ & ios_base::in) {

    if (this->egptr() < __hm_)

      this->setg(this->eback(), this->gptr(), __hm_);

    if (this->gptr() < this->egptr())

      return traits_type::to_int_type(*this->gptr());

  }

  return traits_type::eof();

}

template <class _CharT, class _Traits, class _Allocator>

typename basic_stringbuf<_CharT, _Traits, _Allocator>::int_type

basic_stringbuf<_CharT, _Traits, _Allocator>::pbackfail(int_type __c) {

  if (__hm_ < this->pptr())

    __hm_ = this->pptr();

  if (this->eback() < this->gptr()) {

    if (traits_type::eq_int_type(__c, traits_type::eof())) {

      this->setg(this->eback(), this->gptr() - 1, __hm_);

      return traits_type::not_eof(__c);

    }

    if ((__mode_ & ios_base::out) || traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1])) {

      this->setg(this->eback(), this->gptr() - 1, __hm_);

      *this->gptr() = traits_type::to_char_type(__c);

      return __c;

    }

  }

  return traits_type::eof();

}

template <class _CharT, class _Traits, class _Allocator>

typename basic_stringbuf<_CharT, _Traits, _Allocator>::int_type

basic_stringbuf<_CharT, _Traits, _Allocator>::overflow(int_type __c) {

  if (!traits_type::eq_int_type(__c, traits_type::eof())) {

    ptrdiff_t __ninp = this->gptr() - this->eback();

    if (this->pptr() == this->epptr()) {

      if (!(__mode_ & ios_base::out))

        return traits_type::eof();

#ifndef _LIBCPP_HAS_NO_EXCEPTIONS

      try {

#endif // _LIBCPP_HAS_NO_EXCEPTIONS

        ptrdiff_t __nout = this->pptr() - this->pbase();

        ptrdiff_t __hm   = __hm_ - this->pbase();

        __str_.push_back(char_type());

        __str_.resize(__str_.capacity());

        char_type* __p = const_cast<char_type*>(__str_.data());

        this->setp(__p, __p + __str_.size());

        this->__pbump(__nout);

        __hm_ = this->pbase() + __hm;

#ifndef _LIBCPP_HAS_NO_EXCEPTIONS

      } catch (...) {

        return traits_type::eof();

      }

#endif // _LIBCPP_HAS_NO_EXCEPTIONS

    }

    __hm_ = std::max(this->pptr() + 1, __hm_);

    if (__mode_ & ios_base::in) {

      char_type* __p = const_cast<char_type*>(__str_.data());

      this->setg(__p, __p + __ninp, __hm_);

    }

    return this->sputc(traits_type::to_char_type(__c));

  }

  return traits_type::not_eof(__c);

}

template <class _CharT, class _Traits, class _Allocator>

typename basic_stringbuf<_CharT, _Traits, _Allocator>::pos_type basic_stringbuf<_CharT, _Traits, _Allocator>::seekoff(

    off_type __off, ios_base::seekdir __way, ios_base::openmode __wch) {

  if (__hm_ < this->pptr())

    __hm_ = this->pptr();

  if ((__wch & (ios_base::in | ios_base::out)) == 0)

    return pos_type(-1);

  if ((__wch & (ios_base::in | ios_base::out)) == (ios_base::in | ios_base::out) && __way == ios_base::cur)

    return pos_type(-1);

  const ptrdiff_t __hm = __hm_ == nullptr ? 0 : __hm_ - __str_.data();

  off_type __noff;

  switch (__way) {

  case ios_base::beg:

    __noff = 0;

    break;

  case ios_base::cur:

    if (__wch & ios_base::in)

      __noff = this->gptr() - this->eback();

    else

      __noff = this->pptr() - this->pbase();

    break;

  case ios_base::end:

    __noff = __hm;

    break;

  default:

    return pos_type(-1);

  }

  __noff += __off;

  if (__noff < 0 || __hm < __noff)

    return pos_type(-1);

  if (__noff != 0) {

    if ((__wch & ios_base::in) && this->gptr() == nullptr)

      return pos_type(-1);

    if ((__wch & ios_base::out) && this->pptr() == nullptr)

      return pos_type(-1);

  }

  if (__wch & ios_base::in)

    this->setg(this->eback(), this->eback() + __noff, __hm_);

  if (__wch & ios_base::out) {

    this->setp(this->pbase(), this->epptr());

    this->__pbump(__noff);

  }

  return pos_type(__noff);

}

// Class template basic_istringstream [istringstream]

template <class _CharT, class _Traits, class _Allocator>

class _LIBCPP_TEMPLATE_VIS basic_istringstream : public basic_istream<_CharT, _Traits> {

public:

  typedef _CharT char_type;

  typedef _Traits traits_type;

  typedef typename traits_type::int_type int_type;

  typedef typename traits_type::pos_type pos_type;

  typedef typename traits_type::off_type off_type;

  typedef _Allocator allocator_type;

  typedef basic_string<char_type, traits_type, allocator_type> string_type;

private:

  basic_stringbuf<char_type, traits_type, allocator_type> __sb_;

public:

  // [istringstream.cons] Constructors:

  _LIBCPP_HIDE_FROM_ABI basic_istringstream() : basic_istream<_CharT, _Traits>(&__sb_), __sb_(ios_base::in) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_istringstream(ios_base::openmode __wch)

      : basic_istream<_CharT, _Traits>(&__sb_), __sb_(__wch | ios_base::in) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_istringstream(const string_type& __s, ios_base::openmode __wch = ios_base::in)

      : basic_istream<_CharT, _Traits>(&__sb_), __sb_(__s, __wch | ios_base::in) {}

#if _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI basic_istringstream(ios_base::openmode __wch, const _Allocator& __a)

      : basic_istream<_CharT, _Traits>(std::addressof(__sb_)), __sb_(__wch | ios_base::in, __a) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_istringstream(string_type&& __s, ios_base::openmode __wch = ios_base::in)

      : basic_istream<_CharT, _Traits>(std::addressof(__sb_)), __sb_(std::move(__s), __wch | ios_base::in) {}

  template <class _SAlloc>

  _LIBCPP_HIDE_FROM_ABI basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __s, const _Allocator& __a)

      : basic_istringstream(__s, ios_base::in, __a) {}

  template <class _SAlloc>

  _LIBCPP_HIDE_FROM_ABI basic_istringstream(

      const basic_string<_CharT, _Traits, _SAlloc>& __s, ios_base::openmode __wch, const _Allocator& __a)

      : basic_istream<_CharT, _Traits>(std::addressof(__sb_)), __sb_(__s, __wch | ios_base::in, __a) {}

  template <class _SAlloc>

  _LIBCPP_HIDE_FROM_ABI explicit basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __s,

                                                     ios_base::openmode __wch = ios_base::in)

      : basic_istream<_CharT, _Traits>(std::addressof(__sb_)), __sb_(__s, __wch | ios_base::in) {}

#endif // _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI basic_istringstream(basic_istringstream&& __rhs)

      : basic_istream<_CharT, _Traits>(std::move(__rhs)), __sb_(std::move(__rhs.__sb_)) {

    basic_istream<_CharT, _Traits>::set_rdbuf(&__sb_);

  }

  // [istringstream.assign] Assign and swap:

  basic_istringstream& operator=(basic_istringstream&& __rhs) {

    basic_istream<char_type, traits_type>::operator=(std::move(__rhs));

    __sb_ = std::move(__rhs.__sb_);

    return *this;

  }

  _LIBCPP_HIDE_FROM_ABI void swap(basic_istringstream& __rhs) {

    basic_istream<char_type, traits_type>::swap(__rhs);

    __sb_.swap(__rhs.__sb_);

  }

  // [istringstream.members] Member functions:

  _LIBCPP_HIDE_FROM_ABI basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const {

    return const_cast<basic_stringbuf<char_type, traits_type, allocator_type>*>(&__sb_);

  }

#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_BUILDING_LIBRARY)

  _LIBCPP_HIDE_FROM_ABI string_type str() const { return __sb_.str(); }

#else

  _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() const& { return __sb_.str(); }

  _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() && { return std::move(__sb_).str(); }

#endif

#if _LIBCPP_STD_VER >= 20

  template <class _SAlloc>

    requires __is_allocator<_SAlloc>::value

  _LIBCPP_HIDE_FROM_ABI basic_string<char_type, traits_type, _SAlloc> str(const _SAlloc& __sa) const {

    return __sb_.str(__sa);

  }

  _LIBCPP_HIDE_FROM_ABI basic_string_view<char_type, traits_type> view() const noexcept { return __sb_.view(); }

#endif // _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI void str(const string_type& __s) { __sb_.str(__s); }

#if _LIBCPP_STD_VER >= 20

  template <class _SAlloc>

  _LIBCPP_HIDE_FROM_ABI void str(const basic_string<char_type, traits_type, _SAlloc>& __s) {

    __sb_.str(__s);

  }

  _LIBCPP_HIDE_FROM_ABI void str(string_type&& __s) { __sb_.str(std::move(__s)); }

#endif // _LIBCPP_STD_VER >= 20

};

template <class _CharT, class _Traits, class _Allocator>

inline _LIBCPP_HIDE_FROM_ABI void

swap(basic_istringstream<_CharT, _Traits, _Allocator>& __x, basic_istringstream<_CharT, _Traits, _Allocator>& __y) {

  __x.swap(__y);

}

// Class template basic_ostringstream [ostringstream]

template <class _CharT, class _Traits, class _Allocator>

class _LIBCPP_TEMPLATE_VIS basic_ostringstream : public basic_ostream<_CharT, _Traits> {

public:

  typedef _CharT char_type;

  typedef _Traits traits_type;

  typedef typename traits_type::int_type int_type;

  typedef typename traits_type::pos_type pos_type;

  typedef typename traits_type::off_type off_type;

  typedef _Allocator allocator_type;

  typedef basic_string<char_type, traits_type, allocator_type> string_type;

private:

  basic_stringbuf<char_type, traits_type, allocator_type> __sb_;

public:

  // [ostringstream.cons] Constructors:

  _LIBCPP_HIDE_FROM_ABI basic_ostringstream() : basic_ostream<_CharT, _Traits>(&__sb_), __sb_(ios_base::out) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_ostringstream(ios_base::openmode __wch)

      : basic_ostream<_CharT, _Traits>(&__sb_), __sb_(__wch | ios_base::out) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_ostringstream(const string_type& __s, ios_base::openmode __wch = ios_base::out)

      : basic_ostream<_CharT, _Traits>(&__sb_), __sb_(__s, __wch | ios_base::out) {}

#if _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI basic_ostringstream(ios_base::openmode __wch, const _Allocator& __a)

      : basic_ostream<_CharT, _Traits>(std::addressof(__sb_)), __sb_(__wch | ios_base::out, __a) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_ostringstream(string_type&& __s, ios_base::openmode __wch = ios_base::out)

      : basic_ostream<_CharT, _Traits>(std::addressof(__sb_)), __sb_(std::move(__s), __wch | ios_base::out) {}

  template <class _SAlloc>

  _LIBCPP_HIDE_FROM_ABI basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __s, const _Allocator& __a)

      : basic_ostringstream(__s, ios_base::out, __a) {}

  template <class _SAlloc>

  _LIBCPP_HIDE_FROM_ABI basic_ostringstream(

      const basic_string<_CharT, _Traits, _SAlloc>& __s, ios_base::openmode __wch, const _Allocator& __a)

      : basic_ostream<_CharT, _Traits>(std::addressof(__sb_)), __sb_(__s, __wch | ios_base::out, __a) {}

  template <class _SAlloc>

    requires(!is_same_v<_SAlloc, allocator_type>)

  _LIBCPP_HIDE_FROM_ABI explicit basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __s,

                                                     ios_base::openmode __wch = ios_base::out)

      : basic_ostream<_CharT, _Traits>(std::addressof(__sb_)), __sb_(__s, __wch | ios_base::out) {}

#endif // _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI basic_ostringstream(basic_ostringstream&& __rhs)

      : basic_ostream<_CharT, _Traits>(std::move(__rhs)), __sb_(std::move(__rhs.__sb_)) {

    basic_ostream<_CharT, _Traits>::set_rdbuf(&__sb_);

  }

  // [ostringstream.assign] Assign and swap:

  basic_ostringstream& operator=(basic_ostringstream&& __rhs) {

    basic_ostream<char_type, traits_type>::operator=(std::move(__rhs));

    __sb_ = std::move(__rhs.__sb_);

    return *this;

  }

  _LIBCPP_HIDE_FROM_ABI void swap(basic_ostringstream& __rhs) {

    basic_ostream<char_type, traits_type>::swap(__rhs);

    __sb_.swap(__rhs.__sb_);

  }

  // [ostringstream.members] Member functions:

  _LIBCPP_HIDE_FROM_ABI basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const {

    return const_cast<basic_stringbuf<char_type, traits_type, allocator_type>*>(&__sb_);

  }

#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_BUILDING_LIBRARY)

  _LIBCPP_HIDE_FROM_ABI string_type str() const { return __sb_.str(); }

#else

  _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() const& { return __sb_.str(); }

  _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() && { return std::move(__sb_).str(); }

#endif

#if _LIBCPP_STD_VER >= 20

  template <class _SAlloc>

    requires __is_allocator<_SAlloc>::value

  _LIBCPP_HIDE_FROM_ABI basic_string<char_type, traits_type, _SAlloc> str(const _SAlloc& __sa) const {

    return __sb_.str(__sa);

  }

  _LIBCPP_HIDE_FROM_ABI basic_string_view<char_type, traits_type> view() const noexcept { return __sb_.view(); }

#endif // _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI void str(const string_type& __s) { __sb_.str(__s); }

#if _LIBCPP_STD_VER >= 20

  template <class _SAlloc>

  _LIBCPP_HIDE_FROM_ABI void str(const basic_string<char_type, traits_type, _SAlloc>& __s) {

    __sb_.str(__s);

  }

  _LIBCPP_HIDE_FROM_ABI void str(string_type&& __s) { __sb_.str(std::move(__s)); }

#endif // _LIBCPP_STD_VER >= 20

};

template <class _CharT, class _Traits, class _Allocator>

inline _LIBCPP_HIDE_FROM_ABI void

swap(basic_ostringstream<_CharT, _Traits, _Allocator>& __x, basic_ostringstream<_CharT, _Traits, _Allocator>& __y) {

  __x.swap(__y);

}

// Class template basic_stringstream [stringstream]

template <class _CharT, class _Traits, class _Allocator>

class _LIBCPP_TEMPLATE_VIS basic_stringstream : public basic_iostream<_CharT, _Traits> {

public:

  typedef _CharT char_type;

  typedef _Traits traits_type;

  typedef typename traits_type::int_type int_type;

  typedef typename traits_type::pos_type pos_type;

  typedef typename traits_type::off_type off_type;

  typedef _Allocator allocator_type;

  typedef basic_string<char_type, traits_type, allocator_type> string_type;

private:

  basic_stringbuf<char_type, traits_type, allocator_type> __sb_;

public:

  // [stringstream.cons] constructors

  _LIBCPP_HIDE_FROM_ABI basic_stringstream()

      : basic_iostream<_CharT, _Traits>(&__sb_), __sb_(ios_base::in | ios_base::out) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_stringstream(ios_base::openmode __wch)

      : basic_iostream<_CharT, _Traits>(&__sb_), __sb_(__wch) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_stringstream(const string_type& __s,

                                                    ios_base::openmode __wch = ios_base::in | ios_base::out)

      : basic_iostream<_CharT, _Traits>(&__sb_), __sb_(__s, __wch) {}

#if _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI basic_stringstream(ios_base::openmode __wch, const _Allocator& __a)

      : basic_iostream<_CharT, _Traits>(std::addressof(__sb_)), __sb_(__wch, __a) {}

  _LIBCPP_HIDE_FROM_ABI explicit basic_stringstream(string_type&& __s,

                                                    ios_base::openmode __wch = ios_base::out | ios_base::in)

      : basic_iostream<_CharT, _Traits>(std::addressof(__sb_)), __sb_(std::move(__s), __wch) {}

  template <class _SAlloc>

  _LIBCPP_HIDE_FROM_ABI basic_stringstream(const basic_string<_CharT, _Traits, _SAlloc>& __s, const _Allocator& __a)

      : basic_stringstream(__s, ios_base::out | ios_base::in, __a) {}

  template <class _SAlloc>