sstream.tcc

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// String based streams -*- C++ -*-

// Copyright (C) 1997-2025 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file bits/sstream.tcc
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{sstream}
 */

//
// ISO C++ 14882: 27.7  String-based streams
//

#ifndef _SSTREAM_TCC
#define _SSTREAM_TCC 1

#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wc++11-extensions" // extern template

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  template <class _CharT, class _Traits, class _Alloc>
    typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
    basic_stringbuf<_CharT, _Traits, _Alloc>::
    pbackfail(int_type __c)
    {
      int_type __ret = traits_type::eof();
      if (this->eback() < this->gptr())
        {
          // Try to put back __c into input sequence in one of three ways.
          // Order these tests done in is unspecified by the standard.
          const bool __testeof = traits_type::eq_int_type(__c, __ret);
          if (!__testeof)
            {
              const bool __testeq = traits_type::eq(traits_type::
                                                    to_char_type(__c),
                                                    this->gptr()[-1]);    
              const bool __testout = this->_M_mode & ios_base::out;
              if (__testeq || __testout)
                {
                  this->gbump(-1);
                  if (!__testeq)
                    *this->gptr() = traits_type::to_char_type(__c);
                  __ret = __c;
                }
            }
          else
            {
              this->gbump(-1);
              __ret = traits_type::not_eof(__c);
            }
        }
      return __ret;
    }

  template <class _CharT, class _Traits, class _Alloc>
    typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
    basic_stringbuf<_CharT, _Traits, _Alloc>::
    overflow(int_type __c)
    {
      const bool __testout = this->_M_mode & ios_base::out;
      if (__builtin_expect(!__testout, false))
        return traits_type::eof();

      const bool __testeof = traits_type::eq_int_type(__c, traits_type::eof());
      if (__builtin_expect(__testeof, false))
        return traits_type::not_eof(__c);

      const __size_type __capacity = _M_string.capacity();

#if _GLIBCXX_USE_CXX11_ABI
      if (size_t(this->epptr() - this->pbase()) < __capacity)
        {
          // There is additional capacity in _M_string that can be used.
          char_type* __base = const_cast<char_type*>(_M_string.data());
          _M_pbump(__base, __base + __capacity, this->pptr() - this->pbase());
          if (_M_mode & ios_base::in)
            {
              const __size_type __nget = this->gptr() - this->eback();
              const __size_type __eget = this->egptr() - this->eback();
              this->setg(__base, __base + __nget, __base + __eget + 1);
            }
          *this->pptr() = traits_type::to_char_type(__c);
          this->pbump(1);
          return __c;
        }
#endif

      const __size_type __max_size = _M_string.max_size();
      const bool __testput = this->pptr() < this->epptr();
      if (__builtin_expect(!__testput && __capacity == __max_size, false))
        return traits_type::eof();

      // Try to append __c into output sequence in one of two ways.
      // Order these tests done in is unspecified by the standard.
      const char_type __conv = traits_type::to_char_type(__c);
      if (!__testput)
        {
          // NB: Start ostringstream buffers at 512 chars.  This is an
          // experimental value (pronounced "arbitrary" in some of the
          // hipper English-speaking countries), and can be changed to
          // suit particular needs.
          //
          // _GLIBCXX_RESOLVE_LIB_DEFECTS
          // 169. Bad efficiency of overflow() mandated
          // 432. stringbuf::overflow() makes only one write position
          //      available
          const __size_type __opt_len = std::max(__size_type(2 * __capacity),
                                                 __size_type(512));
          const __size_type __len = std::min(__opt_len, __max_size);
          __string_type __tmp(_M_string.get_allocator());
          __tmp.reserve(__len);
          if (this->pbase())
            __tmp.assign(this->pbase(), this->epptr() - this->pbase());
          __tmp.push_back(__conv);
          _M_string.swap(__tmp);
          _M_sync(const_cast<char_type*>(_M_string.data()),
                  this->gptr() - this->eback(), this->pptr() - this->pbase());
        }
      else
        *this->pptr() = __conv;
      this->pbump(1);
      return __c;
    }

  template <class _CharT, class _Traits, class _Alloc>
    typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
    basic_stringbuf<_CharT, _Traits, _Alloc>::
    underflow()
    {
      int_type __ret = traits_type::eof();
      const bool __testin = this->_M_mode & ios_base::in;
      if (__testin)
        {
          // Update egptr() to match the actual string end.
          _M_update_egptr();

          if (this->gptr() < this->egptr())
            __ret = traits_type::to_int_type(*this->gptr());
        }
      return __ret;
    }

  template <class _CharT, class _Traits, class _Alloc>
    typename basic_stringbuf<_CharT, _Traits, _Alloc>::pos_type
    basic_stringbuf<_CharT, _Traits, _Alloc>::
    seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode)
    {
      pos_type __ret =  pos_type(off_type(-1));
      bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
      bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
      const bool __testboth = __testin && __testout && __way != ios_base::cur;
      __testin &= !(__mode & ios_base::out);
      __testout &= !(__mode & ios_base::in);

      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 453. basic_stringbuf::seekoff need not always fail for an empty stream.
      const char_type* __beg = __testin ? this->eback() : this->pbase();
      if ((__beg || !__off) && (__testin || __testout || __testboth))
        {
          _M_update_egptr();

          off_type __newoffi = __off;
          off_type __newoffo = __newoffi;
          if (__way == ios_base::cur)
            {
              __newoffi += this->gptr() - __beg;
              __newoffo += this->pptr() - __beg;
            }
          else if (__way == ios_base::end)
            __newoffo = __newoffi += this->egptr() - __beg;

          if ((__testin || __testboth)
              && __newoffi >= 0
              && this->egptr() - __beg >= __newoffi)
            {
              this->setg(this->eback(), this->eback() + __newoffi,
                         this->egptr());
              __ret = pos_type(__newoffi);
            }
          if ((__testout || __testboth)
              && __newoffo >= 0
              && this->egptr() - __beg >= __newoffo)
            {
              _M_pbump(this->pbase(), this->epptr(), __newoffo);
              __ret = pos_type(__newoffo);
            }
        }
      return __ret;
    }

  template <class _CharT, class _Traits, class _Alloc>
    typename basic_stringbuf<_CharT, _Traits, _Alloc>::pos_type
    basic_stringbuf<_CharT, _Traits, _Alloc>::
    seekpos(pos_type __sp, ios_base::openmode __mode)
    {
      pos_type __ret =  pos_type(off_type(-1));
      const bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
      const bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;

      const char_type* __beg = __testin ? this->eback() : this->pbase();
      if ((__beg || !off_type(__sp)) && (__testin || __testout))
        {
          _M_update_egptr();

          const off_type __pos(__sp);
          const bool __testpos = (0 <= __pos
                                  && __pos <= this->egptr() - __beg);
          if (__testpos)
            {
              if (__testin)
                this->setg(this->eback(), this->eback() + __pos,
                           this->egptr());
              if (__testout)
                _M_pbump(this->pbase(), this->epptr(), __pos);
              __ret = __sp;
            }
        }
      return __ret;
    }

  template <class _CharT, class _Traits, class _Alloc>
    void
    basic_stringbuf<_CharT, _Traits, _Alloc>::
    _M_sync(char_type* __base, __size_type __i, __size_type __o)
    {
      const bool __testin = _M_mode & ios_base::in;
      const bool __testout = _M_mode & ios_base::out;
      char_type* __endg = __base + _M_string.size();
      char_type* __endp = __base + _M_string.capacity();

      if (__base != _M_string.data())
        {
          // setbuf: __i == size of buffer area (_M_string.size() == 0).
          __endg += __i;
          __i = 0;
          __endp = __endg;
        }

      if (__testin)
        this->setg(__base, __base + __i, __endg);
      if (__testout)
        {
          _M_pbump(__base, __endp, __o);
          // egptr() always tracks the string end.  When !__testin,
          // for the correct functioning of the streambuf inlines
          // the other get area pointers are identical.
          if (!__testin)
            this->setg(__endg, __endg, __endg);
        }
    }

  template <class _CharT, class _Traits, class _Alloc>
    void
    basic_stringbuf<_CharT, _Traits, _Alloc>::
    _M_pbump(char_type* __pbeg, char_type* __pend, off_type __off)
    {
      this->setp(__pbeg, __pend);
      while (__off > __gnu_cxx::__numeric_traits<int>::__max)
        {
          this->pbump(__gnu_cxx::__numeric_traits<int>::__max);
          __off -= __gnu_cxx::__numeric_traits<int>::__max;
        }
      this->pbump(__off);
    }

  // Inhibit implicit instantiations for required instantiations,
  // which are defined via explicit instantiations elsewhere.
#if _GLIBCXX_EXTERN_TEMPLATE
  extern template class basic_stringbuf<char>;
  extern template class basic_istringstream<char>;
  extern template class basic_ostringstream<char>;
  extern template class basic_stringstream<char>;

#ifdef _GLIBCXX_USE_WCHAR_T
  extern template class basic_stringbuf<wchar_t>;
  extern template class basic_istringstream<wchar_t>;
  extern template class basic_ostringstream<wchar_t>;
  extern template class basic_stringstream<wchar_t>;
#endif
#endif

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std

#pragma GCC diagnostic pop
#endif