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// File based streams -*- C++ -*-

// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,

// 2006, 2007, 2008, 2009, 2010, 2011, 2012

// 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

// .

/** @file include/fstream

 *  This is a Standard C++ Library header.

 */

//

// ISO C++ 14882: 27.8  File-based streams

//

#ifndef _GLIBCXX_FSTREAM

#define _GLIBCXX_FSTREAM 1

#pragma GCC system_header

#include 

#include 

#include 

#include              // For BUFSIZ

#include   // For __basic_file, __c_lock

#if __cplusplus >= 201103L

#include              // For std::string overloads.

#endif

namespace std _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  // [27.8.1.1] template class basic_filebuf

  /**

   *  @brief  The actual work of input and output (for files).

   *  @ingroup io

   *

   *  @tparam _CharT  Type of character stream.

   *  @tparam _Traits  Traits for character type, defaults to

   *                   char_traits<_CharT>.

   *

   *  This class associates both its input and output sequence with an

   *  external disk file, and maintains a joint file position for both

   *  sequences.  Many of its semantics are described in terms of similar

   *  behavior in the Standard C Library's @c FILE streams.

   *

   *  Requirements on traits_type, specific to this class:

   *  - traits_type::pos_type must be fpos

   *  - traits_type::off_type must be streamoff

   *  - traits_type::state_type must be Assignable and DefaultConstructible,

   *  - traits_type::state_type() must be the initial state for codecvt.

   */

  template

    class basic_filebuf : public basic_streambuf<_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 basic_streambuf   __streambuf_type;

      typedef basic_filebuf     __filebuf_type;

      typedef __basic_file                      __file_type;

      typedef typename traits_type::state_type          __state_type;

      typedef codecvt    __codecvt_type;

      friend class ios_base; // For sync_with_stdio.

    protected:

      // Data Members:

      // MT lock inherited from libio or other low-level io library.

      __c_lock                  _M_lock;

      // External buffer.

      __file_type               _M_file;

      /// Place to stash in || out || in | out settings for current filebuf.

      ios_base::openmode        _M_mode;

      // Beginning state type for codecvt.

      __state_type              _M_state_beg;

      // During output, the state that corresponds to pptr(),

      // during input, the state that corresponds to egptr() and

      // _M_ext_next.

      __state_type              _M_state_cur;

      // Not used for output. During input, the state that corresponds

      // to eback() and _M_ext_buf.

      __state_type              _M_state_last;

      /// Pointer to the beginning of internal buffer.

      char_type*                _M_buf;

      /**

       *  Actual size of internal buffer. This number is equal to the size

       *  of the put area + 1 position, reserved for the overflow char of

       *  a full area.

       */

      size_t                    _M_buf_size;

      // Set iff _M_buf is allocated memory from _M_allocate_internal_buffer.

      bool                      _M_buf_allocated;

      /**

       *  _M_reading == false && _M_writing == false for @b uncommitted mode;

       *  _M_reading == true for @b read mode;

       *  _M_writing == true for @b write mode;

       *

       *  NB: _M_reading == true && _M_writing == true is unused.

       */

      bool                      _M_reading;

      bool                      _M_writing;

      //@{

      /**

       *  Necessary bits for putback buffer management.

       *

       *  @note pbacks of over one character are not currently supported.

       */

      char_type                 _M_pback;

      char_type*                _M_pback_cur_save;

      char_type*                _M_pback_end_save;

      bool                      _M_pback_init;

      //@}

      // Cached codecvt facet.

      const __codecvt_type*     _M_codecvt;

      /**

       *  Buffer for external characters. Used for input when

       *  codecvt::always_noconv() == false. When valid, this corresponds

       *  to eback().

       */

      char*                     _M_ext_buf;

      /**

       *  Size of buffer held by _M_ext_buf.

       */

      streamsize                _M_ext_buf_size;

      /**

       *  Pointers into the buffer held by _M_ext_buf that delimit a

       *  subsequence of bytes that have been read but not yet converted.

       *  When valid, _M_ext_next corresponds to egptr().

       */

      const char*               _M_ext_next;

      char*                     _M_ext_end;

      /**

       *  Initializes pback buffers, and moves normal buffers to safety.

       *  Assumptions:

       *  _M_in_cur has already been moved back

       */

      void

      _M_create_pback()

      {

        if (!_M_pback_init)

          {

            _M_pback_cur_save = this->gptr();

            _M_pback_end_save = this->egptr();

            this->setg(&_M_pback, &_M_pback, &_M_pback + 1);

            _M_pback_init = true;

          }

      }

      /**

       *  Deactivates pback buffer contents, and restores normal buffer.

       *  Assumptions:

       *  The pback buffer has only moved forward.

       */

      void

      _M_destroy_pback() throw()

      {

        if (_M_pback_init)

          {

            // Length _M_in_cur moved in the pback buffer.

            _M_pback_cur_save += this->gptr() != this->eback();

            this->setg(_M_buf, _M_pback_cur_save, _M_pback_end_save);

            _M_pback_init = false;

          }

      }

    public:

      // Constructors/destructor:

      /**

       *  @brief  Does not open any files.

       *

       *  The default constructor initializes the parent class using its

       *  own default ctor.

       */

      basic_filebuf();

      /**

       *  @brief  The destructor closes the file first.

       */

      virtual

      ~basic_filebuf()

      { this->close(); }

      // Members:

      /**

       *  @brief  Returns true if the external file is open.

       */

      bool

      is_open() const throw()

      { return _M_file.is_open(); }

      /**

       *  @brief  Opens an external file.

       *  @param  __s  The name of the file.

       *  @param  __mode  The open mode flags.

       *  @return  @c this on success, NULL on failure

       *

       *  If a file is already open, this function immediately fails.

       *  Otherwise it tries to open the file named @a __s using the flags

       *  given in @a __mode.

       *

       *  Table 92, adapted here, gives the relation between openmode

       *  combinations and the equivalent fopen() flags.

       *  (NB: lines app, in|out|app, in|app, binary|app, binary|in|out|app,

       *  and binary|in|app per DR 596)

       *  +---------------------------------------------------------+

       *  | ios_base Flag combination            stdio equivalent   |

       *  |binary  in  out  trunc  app                              |

       *  +---------------------------------------------------------+

       *  |             +                        w                  |

       *  |             +           +            a                  |

       *  |                         +            a                  |

       *  |             +     +                  w                  |

       *  |         +                            r                  |

       *  |         +   +                        r+                 |

       *  |         +   +     +                  w+                 |

       *  |         +   +           +            a+                 |

       *  |         +               +            a+                 |

       *  +---------------------------------------------------------+

       *  |   +         +                        wb                 |

       *  |   +         +           +            ab                 |

       *  |   +                     +            ab                 |

       *  |   +         +     +                  wb                 |

       *  |   +     +                            rb                 |

       *  |   +     +   +                        r+b                |

       *  |   +     +   +     +                  w+b                |

       *  |   +     +   +           +            a+b                |

       *  |   +     +               +            a+b                |

       *  +---------------------------------------------------------+

       */

      __filebuf_type*

      open(const char* __s, ios_base::openmode __mode);

#if __cplusplus >= 201103L

      /**

       *  @brief  Opens an external file.

       *  @param  __s  The name of the file.

       *  @param  __mode  The open mode flags.

       *  @return  @c this on success, NULL on failure

       */

      __filebuf_type*

      open(const std::string& __s, ios_base::openmode __mode)

      { return open(__s.c_str(), __mode); }

#endif

      /**

       *  @brief  Closes the currently associated file.

       *  @return  @c this on success, NULL on failure

       *

       *  If no file is currently open, this function immediately fails.

       *

       *  If a put buffer area exists, @c overflow(eof) is

       *  called to flush all the characters.  The file is then

       *  closed.

       *

       *  If any operations fail, this function also fails.

       */

      __filebuf_type*

      close();

    protected:

      void

      _M_allocate_internal_buffer();

      void

      _M_destroy_internal_buffer() throw();

      // [27.8.1.4] overridden virtual functions

      virtual streamsize

      showmanyc();

      // Stroustrup, 1998, p. 628

      // underflow() and uflow() functions are called to get the next

      // character from the real input source when the buffer is empty.

      // Buffered input uses underflow()

      virtual int_type

      underflow();

      virtual int_type

      pbackfail(int_type __c = _Traits::eof());

      // Stroustrup, 1998, p 648

      // The overflow() function is called to transfer characters to the

      // real output destination when the buffer is full. A call to

      // overflow(c) outputs the contents of the buffer plus the

      // character c.

      // 27.5.2.4.5

      // Consume some sequence of the characters in the pending sequence.

      virtual int_type

      overflow(int_type __c = _Traits::eof());

      // Convert internal byte sequence to external, char-based

      // sequence via codecvt.

      bool

      _M_convert_to_external(char_type*, streamsize);

      /**

       *  @brief  Manipulates the buffer.

       *  @param  __s  Pointer to a buffer area.

       *  @param  __n  Size of @a __s.

       *  @return  @c this

       *

       *  If no file has been opened, and both @a __s and @a __n are zero, then

       *  the stream becomes unbuffered.  Otherwise, @c __s is used as a

       *  buffer; see

       *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html

       *  for more.

       */

      virtual __streambuf_type*

      setbuf(char_type* __s, streamsize __n);

      virtual pos_type

      seekoff(off_type __off, ios_base::seekdir __way,

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

      virtual pos_type

      seekpos(pos_type __pos,

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

      // Common code for seekoff, seekpos, and overflow

      pos_type

      _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state);

      int

      _M_get_ext_pos(__state_type &__state);

      virtual int

      sync();

      virtual void

      imbue(const locale& __loc);

      virtual streamsize

      xsgetn(char_type* __s, streamsize __n);

      virtual streamsize

      xsputn(const char_type* __s, streamsize __n);

      // Flushes output buffer, then writes unshift sequence.

      bool

      _M_terminate_output();

      /**

       *  This function sets the pointers of the internal buffer, both get

       *  and put areas. Typically:

       *

       *   __off == egptr() - eback() upon underflow/uflow (@b read mode);

       *   __off == 0 upon overflow (@b write mode);

       *   __off == -1 upon open, setbuf, seekoff/pos (@b uncommitted mode).

       *

       *  NB: epptr() - pbase() == _M_buf_size - 1, since _M_buf_size

       *  reflects the actual allocated memory and the last cell is reserved

       *  for the overflow char of a full put area.

       */

      void

      _M_set_buffer(streamsize __off)

      {

        const bool __testin = _M_mode & ios_base::in;

        const bool __testout = _M_mode & ios_base::out;

        if (__testin && __off > 0)

          this->setg(_M_buf, _M_buf, _M_buf + __off);

        else

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

        if (__testout && __off == 0 && _M_buf_size > 1 )

          this->setp(_M_buf, _M_buf + _M_buf_size - 1);

        else

          this->setp(0, 0);

      }

    };

  // [27.8.1.5] Template class basic_ifstream

  /**

   *  @brief  Controlling input for files.

   *  @ingroup io

   *

   *  @tparam _CharT  Type of character stream.

   *  @tparam _Traits  Traits for character type, defaults to

   *                   char_traits<_CharT>.

   *

   *  This class supports reading from named files, using the inherited

   *  functions from std::basic_istream.  To control the associated

   *  sequence, an instance of std::basic_filebuf is used, which this page

   *  refers to as @c sb.

   */

  template

    class basic_ifstream : public basic_istream<_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;

      // Non-standard types:

      typedef basic_filebuf     __filebuf_type;

      typedef basic_istream     __istream_type;

    private:

      __filebuf_type    _M_filebuf;

    public:

      // Constructors/Destructors:

      /**

       *  @brief  Default constructor.

       *

       *  Initializes @c sb using its default constructor, and passes

       *  @c &sb to the base class initializer.  Does not open any files

       *  (you haven't given it a filename to open).

       */

      basic_ifstream() : __istream_type(), _M_filebuf()

      { this->init(&_M_filebuf); }

      /**

       *  @brief  Create an input file stream.

       *  @param  __s  Null terminated string specifying the filename.

       *  @param  __mode  Open file in specified mode (see std::ios_base).

       *

       *  @c ios_base::in is automatically included in @a __mode.

       *

       *  Tip:  When using std::string to hold the filename, you must use

       *  .c_str() before passing it to this constructor.

       */

      explicit

      basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in)

      : __istream_type(), _M_filebuf()

      {

        this->init(&_M_filebuf);

        this->open(__s, __mode);

      }

#if __cplusplus >= 201103L

      /**

       *  @brief  Create an input file stream.

       *  @param  __s  std::string specifying the filename.

       *  @param  __mode  Open file in specified mode (see std::ios_base).

       *

       *  @c ios_base::in is automatically included in @a __mode.

       */

      explicit

      basic_ifstream(const std::string& __s,

                     ios_base::openmode __mode = ios_base::in)

      : __istream_type(), _M_filebuf()

      {

        this->init(&_M_filebuf);

        this->open(__s, __mode);

      }

#endif

      /**

       *  @brief  The destructor does nothing.

       *

       *  The file is closed by the filebuf object, not the formatting

       *  stream.

       */

      ~basic_ifstream()

      { }

      // Members:

      /**

       *  @brief  Accessing the underlying buffer.

       *  @return  The current basic_filebuf buffer.

       *

       *  This hides both signatures of std::basic_ios::rdbuf().

       */

      __filebuf_type*

      rdbuf() const

      { return const_cast<__filebuf_type*>(&_M_filebuf); }

      /**

       *  @brief  Wrapper to test for an open file.

       *  @return  @c rdbuf()->is_open()

       */

      bool

      is_open()

      { return _M_filebuf.is_open(); }

      // _GLIBCXX_RESOLVE_LIB_DEFECTS

      // 365. Lack of const-qualification in clause 27

      bool

      is_open() const

      { return _M_filebuf.is_open(); }

      /**

       *  @brief  Opens an external file.

       *  @param  __s  The name of the file.

       *  @param  __mode  The open mode flags.

       *

       *  Calls @c std::basic_filebuf::open(s,__mode|in).  If that function

       *  fails, @c failbit is set in the stream's error state.

       *

       *  Tip:  When using std::string to hold the filename, you must use

       *  .c_str() before passing it to this constructor.

       */

      void

      open(const char* __s, ios_base::openmode __mode = ios_base::in)

      {

        if (!_M_filebuf.open(__s, __mode | ios_base::in))

          this->setstate(ios_base::failbit);

        else

          // _GLIBCXX_RESOLVE_LIB_DEFECTS

          // 409. Closing an fstream should clear error state

          this->clear();

      }

#if __cplusplus >= 201103L

      /**

       *  @brief  Opens an external file.

       *  @param  __s  The name of the file.

       *  @param  __mode  The open mode flags.

       *

       *  Calls @c std::basic_filebuf::open(__s,__mode|in).  If that function

       *  fails, @c failbit is set in the stream's error state.

       */

      void

      open(const std::string& __s, ios_base::openmode __mode = ios_base::in)

      {

        if (!_M_filebuf.open(__s, __mode | ios_base::in))

          this->setstate(ios_base::failbit);

        else

          // _GLIBCXX_RESOLVE_LIB_DEFECTS

          // 409. Closing an fstream should clear error state

          this->clear();

      }

#endif

      /**

       *  @brief  Close the file.

       *

       *  Calls @c std::basic_filebuf::close().  If that function

       *  fails, @c failbit is set in the stream's error state.

       */

      void

      close()

      {

        if (!_M_filebuf.close())

          this->setstate(ios_base::failbit);

      }

    };

  // [27.8.1.8] Template class basic_ofstream

  /**

   *  @brief  Controlling output for files.

   *  @ingroup io

   *

   *  @tparam _CharT  Type of character stream.

   *  @tparam _Traits  Traits for character type, defaults to

   *                   char_traits<_CharT>.

   *

   *  This class supports reading from named files, using the inherited

   *  functions from std::basic_ostream.  To control the associated

   *  sequence, an instance of std::basic_filebuf is used, which this page

   *  refers to as @c sb.

   */

  template

    class basic_ofstream : 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;

      // Non-standard types:

      typedef basic_filebuf     __filebuf_type;

      typedef basic_ostream     __ostream_type;

    private:

      __filebuf_type    _M_filebuf;

    public:

      // Constructors:

      /**

       *  @brief  Default constructor.

       *

       *  Initializes @c sb using its default constructor, and passes

       *  @c &sb to the base class initializer.  Does not open any files

       *  (you haven't given it a filename to open).

       */

      basic_ofstream(): __ostream_type(), _M_filebuf()

      { this->init(&_M_filebuf); }

      /**

       *  @brief  Create an output file stream.

       *  @param  __s  Null terminated string specifying the filename.

       *  @param  __mode  Open file in specified mode (see std::ios_base).

       *

       *  @c ios_base::out | @c ios_base::trunc is automatically included in

       *  @a __mode.

       *

       *  Tip:  When using std::string to hold the filename, you must use

       *  .c_str() before passing it to this constructor.

       */

      explicit

      basic_ofstream(const char* __s,

                     ios_base::openmode __mode = ios_base::out|ios_base::trunc)

      : __ostream_type(), _M_filebuf()

      {

        this->init(&_M_filebuf);

        this->open(__s, __mode);

      }

#if __cplusplus >= 201103L

      /**

       *  @brief  Create an output file stream.

       *  @param  __s  std::string specifying the filename.

       *  @param  __mode  Open file in specified mode (see std::ios_base).

       *

       *  @c ios_base::out | @c ios_base::trunc is automatically included in

       *  @a __mode.

       */

      explicit

      basic_ofstream(const std::string& __s,

                     ios_base::openmode __mode = ios_base::out|ios_base::trunc)

      : __ostream_type(), _M_filebuf()

      {

        this->init(&_M_filebuf);

        this->open(__s, __mode);

      }

#endif

      /**

       *  @brief  The destructor does nothing.

       *

       *  The file is closed by the filebuf object, not the formatting

       *  stream.

       */

      ~basic_ofstream()

      { }

      // Members:

      /**

       *  @brief  Accessing the underlying buffer.

       *  @return  The current basic_filebuf buffer.

       *

       *  This hides both signatures of std::basic_ios::rdbuf().

       */

      __filebuf_type*

      rdbuf() const

      { return const_cast<__filebuf_type*>(&_M_filebuf); }

      /**

       *  @brief  Wrapper to test for an open file.

       *  @return  @c rdbuf()->is_open()

       */

      bool

      is_open()

      { return _M_filebuf.is_open(); }

      // _GLIBCXX_RESOLVE_LIB_DEFECTS

      // 365. Lack of const-qualification in clause 27

      bool

      is_open() const

      { return _M_filebuf.is_open(); }

      /**

       *  @brief  Opens an external file.

       *  @param  __s  The name of the file.

       *  @param  __mode  The open mode flags.

       *

       *  Calls @c std::basic_filebuf::open(__s,__mode|out|trunc).  If that

       *  function fails, @c failbit is set in the stream's error state.

       *

       *  Tip:  When using std::string to hold the filename, you must use

       *  .c_str() before passing it to this constructor.

       */

      void

      open(const char* __s,

           ios_base::openmode __mode = ios_base::out | ios_base::trunc)

      {

        if (!_M_filebuf.open(__s, __mode | ios_base::out))

          this->setstate(ios_base::failbit);

        else

          // _GLIBCXX_RESOLVE_LIB_DEFECTS

          // 409. Closing an fstream should clear error state

          this->clear();

      }

#if __cplusplus >= 201103L

      /**

       *  @brief  Opens an external file.

       *  @param  __s  The name of the file.

       *  @param  __mode  The open mode flags.

       *

       *  Calls @c std::basic_filebuf::open(s,mode|out|trunc).  If that

       *  function fails, @c failbit is set in the stream's error state.

       */

      void

      open(const std::string& __s,

           ios_base::openmode __mode = ios_base::out | ios_base::trunc)

      {

        if (!_M_filebuf.open(__s, __mode | ios_base::out))

          this->setstate(ios_base::failbit);

        else

          // _GLIBCXX_RESOLVE_LIB_DEFECTS

          // 409. Closing an fstream should clear error state

          this->clear();

      }

#endif

      /**

       *  @brief  Close the file.

       *

       *  Calls @c std::basic_filebuf::close().  If that function

       *  fails, @c failbit is set in the stream's error state.

       */

      void

      close()

      {

        if (!_M_filebuf.close())

          this->setstate(ios_base::failbit);

      }

    };

  // [27.8.1.11] Template class basic_fstream

  /**

   *  @brief  Controlling input and output for files.

   *  @ingroup io

   *

   *  @tparam _CharT  Type of character stream.

   *  @tparam _Traits  Traits for character type, defaults to

   *                   char_traits<_CharT>.

   *

   *  This class supports reading from and writing to named files, using

   *  the inherited functions from std::basic_iostream.  To control the

   *  associated sequence, an instance of std::basic_filebuf is used, which

   *  this page refers to as @c sb.

   */

  template

    class basic_fstream : 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;

      // Non-standard types:

      typedef basic_filebuf     __filebuf_type;

      typedef basic_ios         __ios_type;

      typedef basic_iostream    __iostream_type;

    private:

      __filebuf_type    _M_filebuf;

    public:

      // Constructors/destructor:

      /**

       *  @brief  Default constructor.

       *

       *  Initializes @c sb using its default constructor, and passes

       *  @c &sb to the base class initializer.  Does not open any files

       *  (you haven't given it a filename to open).

       */

      basic_fstream()

      : __iostream_type(), _M_filebuf()

      { this->init(&_M_filebuf); }

      /**

       *  @brief  Create an input/output file stream.

       *  @param  __s  Null terminated string specifying the filename.

       *  @param  __mode  Open file in specified mode (see std::ios_base).

       *

       *  Tip:  When using std::string to hold the filename, you must use

       *  .c_str() before passing it to this constructor.

       */

      explicit

      basic_fstream(const char* __s,

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

      : __iostream_type(0), _M_filebuf()

      {

        this->init(&_M_filebuf);

        this->open(__s, __mode);

      }

#if __cplusplus >= 201103L

      /**

       *  @brief  Create an input/output file stream.

       *  @param  __s  Null terminated string specifying the filename.

       *  @param  __mode  Open file in specified mode (see std::ios_base).

       */

      explicit

      basic_fstream(const std::string& __s,

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

      : __iostream_type(0), _M_filebuf()

      {

        this->init(&_M_filebuf);

        this->open(__s, __mode);

      }

#endif

      /**

       *  @brief  The destructor does nothing.

       *

       *  The file is closed by the filebuf object, not the formatting

       *  stream.

       */

      ~basic_fstream()

      { }

      // Members:

      /**

       *  @brief  Accessing the underlying buffer.

       *  @return  The current basic_filebuf buffer.

       *

       *  This hides both signatures of std::basic_ios::rdbuf().

       */

      __filebuf_type*

      rdbuf() const

      { return const_cast<__filebuf_type*>(&_M_filebuf); }

      /**

       *  @brief  Wrapper to test for an open file.

       *  @return  @c rdbuf()->is_open()

       */

      bool

      is_open()

      { return _M_filebuf.is_open(); }

      // _GLIBCXX_RESOLVE_LIB_DEFECTS

      // 365. Lack of const-qualification in clause 27

      bool

      is_open() const

      { return _M_filebuf.is_open(); }

      /**

       *  @brief  Opens an external file.

       *  @param  __s  The name of the file.

       *  @param  __mode  The open mode flags.

       *

       *  Calls @c std::basic_filebuf::open(__s,__mode).  If that

       *  function fails, @c failbit is set in the stream's error state.

       *

       *  Tip:  When using std::string to hold the filename, you must use

       *  .c_str() before passing it to this constructor.

       */

      void

      open(const char* __s,

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

      {

        if (!_M_filebuf.open(__s, __mode))

          this->setstate(ios_base::failbit);

        else

          // _GLIBCXX_RESOLVE_LIB_DEFECTS

          // 409. Closing an fstream should clear error state

          this->clear();

      }

#if __cplusplus >= 201103L

      /**

       *  @brief  Opens an external file.

       *  @param  __s  The name of the file.

       *  @param  __mode  The open mode flags.

       *

       *  Calls @c std::basic_filebuf::open(__s,__mode).  If that

       *  function fails, @c failbit is set in the stream's error state.

       */

      void

      open(const std::string& __s,

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

      {

        if (!_M_filebuf.open(__s, __mode))

          this->setstate(ios_base::failbit);

        else

          // _GLIBCXX_RESOLVE_LIB_DEFECTS

          // 409. Closing an fstream should clear error state

          this->clear();

      }

#endif

      /**

       *  @brief  Close the file.

       *

       *  Calls @c std::basic_filebuf::close().  If that function

       *  fails, @c failbit is set in the stream's error state.

       */

      void

      close()

      {

        if (!_M_filebuf.close())

          this->setstate(ios_base::failbit);

      }

    };

_GLIBCXX_END_NAMESPACE_VERSION

} // namespace