// File based streams -*- C++ -*-
	
	// Copyright (C) 1997-2013 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/fstream.tcc
	 *  This is an internal header file, included by other library headers.
	 *  Do not attempt to use it directly. @headername{fstream}
	 */
	
	//
	// ISO C++ 14882: 27.8  File-based streams
	//
	
	#ifndef _FSTREAM_TCC
	#define _FSTREAM_TCC 1
	
	#pragma GCC system_header
	
	#include <bits/cxxabi_forced.h>
	
	namespace std _GLIBCXX_VISIBILITY(default)
	{
	_GLIBCXX_BEGIN_NAMESPACE_VERSION
	
	  template<typename _CharT, typename _Traits>
	    void
	    basic_filebuf<_CharT, _Traits>::
	    _M_allocate_internal_buffer()
	    {
	      // Allocate internal buffer only if one doesn't already exist
	      // (either allocated or provided by the user via setbuf).
	      if (!_M_buf_allocated && !_M_buf)
		{
		  _M_buf = new char_type[_M_buf_size];
		  _M_buf_allocated = true;
		}
	    }
	
	  template<typename _CharT, typename _Traits>
	    void
	    basic_filebuf<_CharT, _Traits>::
	    _M_destroy_internal_buffer() throw()
	    {
	      if (_M_buf_allocated)
		{
		  delete [] _M_buf;
		  _M_buf = 0;
		  _M_buf_allocated = false;
		}
	      delete [] _M_ext_buf;
	      _M_ext_buf = 0;
	      _M_ext_buf_size = 0;
	      _M_ext_next = 0;
	      _M_ext_end = 0;
	    }
	
	  template<typename _CharT, typename _Traits>
	    basic_filebuf<_CharT, _Traits>::
	    basic_filebuf() : __streambuf_type(), _M_lock(), _M_file(&_M_lock),
	    _M_mode(ios_base::openmode(0)), _M_state_beg(), _M_state_cur(),
	    _M_state_last(), _M_buf(0), _M_buf_size(BUFSIZ),
	    _M_buf_allocated(false), _M_reading(false), _M_writing(false), _M_pback(), 
	    _M_pback_cur_save(0), _M_pback_end_save(0), _M_pback_init(false),
	    _M_codecvt(0), _M_ext_buf(0), _M_ext_buf_size(0), _M_ext_next(0),
	    _M_ext_end(0)
	    {
	      if (has_facet<__codecvt_type>(this->_M_buf_locale))
		_M_codecvt = &use_facet<__codecvt_type>(this->_M_buf_locale);
	    }
	
	  template<typename _CharT, typename _Traits>
	    typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
	    basic_filebuf<_CharT, _Traits>::
	    open(const char* __s, ios_base::openmode __mode)
	    {
	      __filebuf_type *__ret = 0;
	      if (!this->is_open())
		{
		  _M_file.open(__s, __mode);
		  if (this->is_open())
		    {
		      _M_allocate_internal_buffer();
		      _M_mode = __mode;
	
		      // Setup initial buffer to 'uncommitted' mode.
		      _M_reading = false;
		      _M_writing = false;
		      _M_set_buffer(-1);
	
		      // Reset to initial state.
		      _M_state_last = _M_state_cur = _M_state_beg;
	
		      // 27.8.1.3,4
		      if ((__mode & ios_base::ate)
			  && this->seekoff(0, ios_base::end, __mode)
			  == pos_type(off_type(-1)))
			this->close();
		      else
			__ret = this;
		    }
		}
	      return __ret;
	    }
	
	  template<typename _CharT, typename _Traits>
	    typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
	    basic_filebuf<_CharT, _Traits>::
	    close()
	    {
	      if (!this->is_open())
		return 0;
	
	      bool __testfail = false;
	      {
		// NB: Do this here so that re-opened filebufs will be cool...
		struct __close_sentry
		{
		  basic_filebuf *__fb;
		  __close_sentry (basic_filebuf *__fbi): __fb(__fbi) { }
		  ~__close_sentry ()
		  {
		    __fb->_M_mode = ios_base::openmode(0);
		    __fb->_M_pback_init = false;
		    __fb->_M_destroy_internal_buffer();
		    __fb->_M_reading = false;
		    __fb->_M_writing = false;
		    __fb->_M_set_buffer(-1);
		    __fb->_M_state_last = __fb->_M_state_cur = __fb->_M_state_beg;
		  }
		} __cs (this);
	
		__try
		  {
		    if (!_M_terminate_output())
		      __testfail = true;
		  }
		__catch(__cxxabiv1::__forced_unwind&)
		  {
		    _M_file.close();
		    __throw_exception_again;
		  }
		__catch(...)
		  { __testfail = true; }
	      }
	
	      if (!_M_file.close())
		__testfail = true;
	
	      if (__testfail)
		return 0;
	      else
		return this;
	    }
	
	  template<typename _CharT, typename _Traits>
	    streamsize
	    basic_filebuf<_CharT, _Traits>::
	    showmanyc()
	    {
	      streamsize __ret = -1;
	      const bool __testin = _M_mode & ios_base::in;
	      if (__testin && this->is_open())
		{
		  // For a stateful encoding (-1) the pending sequence might be just
		  // shift and unshift prefixes with no actual character.
		  __ret = this->egptr() - this->gptr();
	
	#if _GLIBCXX_HAVE_DOS_BASED_FILESYSTEM
		  // About this workaround, see libstdc++/20806.
		  const bool __testbinary = _M_mode & ios_base::binary;
		  if (__check_facet(_M_codecvt).encoding() >= 0
		      && __testbinary)
	#else
		  if (__check_facet(_M_codecvt).encoding() >= 0)
	#endif
		    __ret += _M_file.showmanyc() / _M_codecvt->max_length();
		}
	      return __ret;
	    }
	
	  template<typename _CharT, typename _Traits>
	    typename basic_filebuf<_CharT, _Traits>::int_type
	    basic_filebuf<_CharT, _Traits>::
	    underflow()
	    {
	      int_type __ret = traits_type::eof();
	      const bool __testin = _M_mode & ios_base::in;
	      if (__testin)
		{
		  if (_M_writing)
		    {
		      if (overflow() == traits_type::eof())
			return __ret;
		      _M_set_buffer(-1);
		      _M_writing = false;
		    }
		  // Check for pback madness, and if so switch back to the
		  // normal buffers and jet outta here before expensive
		  // fileops happen...
		  _M_destroy_pback();
	
		  if (this->gptr() < this->egptr())
		    return traits_type::to_int_type(*this->gptr());
	
		  // Get and convert input sequence.
		  const size_t __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1;
	
		  // Will be set to true if ::read() returns 0 indicating EOF.
		  bool __got_eof = false;
		  // Number of internal characters produced.
		  streamsize __ilen = 0;
		  codecvt_base::result __r = codecvt_base::ok;
		  if (__check_facet(_M_codecvt).always_noconv())
		    {
		      __ilen = _M_file.xsgetn(reinterpret_cast<char*>(this->eback()),
					      __buflen);
		      if (__ilen == 0)
			__got_eof = true;
		    }
		  else
		    {
	              // Worst-case number of external bytes.
		      // XXX Not done encoding() == -1.
		      const int __enc = _M_codecvt->encoding();
		      streamsize __blen; // Minimum buffer size.
		      streamsize __rlen; // Number of chars to read.
		      if (__enc > 0)
			__blen = __rlen = __buflen * __enc;
		      else
			{
			  __blen = __buflen + _M_codecvt->max_length() - 1;
			  __rlen = __buflen;
			}
		      const streamsize __remainder = _M_ext_end - _M_ext_next;
		      __rlen = __rlen > __remainder ? __rlen - __remainder : 0;
	
		      // An imbue in 'read' mode implies first converting the external
		      // chars already present.
		      if (_M_reading && this->egptr() == this->eback() && __remainder)
			__rlen = 0;
	
		      // Allocate buffer if necessary and move unconverted
		      // bytes to front.
		      if (_M_ext_buf_size < __blen)
			{
			  char* __buf = new char[__blen];
			  if (__remainder)
			    __builtin_memcpy(__buf, _M_ext_next, __remainder);
	
			  delete [] _M_ext_buf;
			  _M_ext_buf = __buf;
			  _M_ext_buf_size = __blen;
			}
		      else if (__remainder)
			__builtin_memmove(_M_ext_buf, _M_ext_next, __remainder);
	
		      _M_ext_next = _M_ext_buf;
		      _M_ext_end = _M_ext_buf + __remainder;
		      _M_state_last = _M_state_cur;
	
		      do
			{
			  if (__rlen > 0)
			    {
			      // Sanity check!
			      // This may fail if the return value of
			      // codecvt::max_length() is bogus.
			      if (_M_ext_end - _M_ext_buf + __rlen > _M_ext_buf_size)
				{
				  __throw_ios_failure(__N("basic_filebuf::underflow "
						      "codecvt::max_length() "
						      "is not valid"));
				}
			      streamsize __elen = _M_file.xsgetn(_M_ext_end, __rlen);
			      if (__elen == 0)
				__got_eof = true;
			      else if (__elen == -1)
				break;
			      _M_ext_end += __elen;
			    }
	
			  char_type* __iend = this->eback();
			  if (_M_ext_next < _M_ext_end)
			    __r = _M_codecvt->in(_M_state_cur, _M_ext_next,
						 _M_ext_end, _M_ext_next,
						 this->eback(),
						 this->eback() + __buflen, __iend);
			  if (__r == codecvt_base::noconv)
			    {
			      size_t __avail = _M_ext_end - _M_ext_buf;
			      __ilen = std::min(__avail, __buflen);
			      traits_type::copy(this->eback(),
						reinterpret_cast<char_type*>
						(_M_ext_buf), __ilen);
			      _M_ext_next = _M_ext_buf + __ilen;
			    }
			  else
			    __ilen = __iend - this->eback();
	
			  // _M_codecvt->in may return error while __ilen > 0: this is
			  // ok, and actually occurs in case of mixed encodings (e.g.,
			  // XML files).
			  if (__r == codecvt_base::error)
			    break;
	
			  __rlen = 1;
			}
		      while (__ilen == 0 && !__got_eof);
		    }
	
		  if (__ilen > 0)
		    {
		      _M_set_buffer(__ilen);
		      _M_reading = true;
		      __ret = traits_type::to_int_type(*this->gptr());
		    }
		  else if (__got_eof)
		    {
		      // If the actual end of file is reached, set 'uncommitted'
		      // mode, thus allowing an immediate write without an
		      // intervening seek.
		      _M_set_buffer(-1);
		      _M_reading = false;
		      // However, reaching it while looping on partial means that
		      // the file has got an incomplete character.
		      if (__r == codecvt_base::partial)
			__throw_ios_failure(__N("basic_filebuf::underflow "
					    "incomplete character in file"));
		    }
		  else if (__r == codecvt_base::error)
		    __throw_ios_failure(__N("basic_filebuf::underflow "
					"invalid byte sequence in file"));
		  else
		    __throw_ios_failure(__N("basic_filebuf::underflow "
					"error reading the file"));
		}
	      return __ret;
	    }
	
	  template<typename _CharT, typename _Traits>
	    typename basic_filebuf<_CharT, _Traits>::int_type
	    basic_filebuf<_CharT, _Traits>::
	    pbackfail(int_type __i)
	    {
	      int_type __ret = traits_type::eof();
	      const bool __testin = _M_mode & ios_base::in;
	      if (__testin)
		{
		  if (_M_writing)
		    {
		      if (overflow() == traits_type::eof())
			return __ret;
		      _M_set_buffer(-1);
		      _M_writing = false;
		    }
		  // Remember whether the pback buffer is active, otherwise below
		  // we may try to store in it a second char (libstdc++/9761).
		  const bool __testpb = _M_pback_init;
		  const bool __testeof = traits_type::eq_int_type(__i, __ret);
		  int_type __tmp;
		  if (this->eback() < this->gptr())
		    {
		      this->gbump(-1);
		      __tmp = traits_type::to_int_type(*this->gptr());
		    }
		  else if (this->seekoff(-1, ios_base::cur) != pos_type(off_type(-1)))
		    {
		      __tmp = this->underflow();
		      if (traits_type::eq_int_type(__tmp, __ret))
			return __ret;
		    }
		  else
		    {
		      // At the beginning of the buffer, need to make a
		      // putback position available.  But the seek may fail
		      // (f.i., at the beginning of a file, see
		      // libstdc++/9439) and in that case we return
		      // traits_type::eof().
		      return __ret;
		    }
	
		  // Try to put back __i into input sequence in one of three ways.
		  // Order these tests done in is unspecified by the standard.
		  if (!__testeof && traits_type::eq_int_type(__i, __tmp))
		    __ret = __i;
		  else if (__testeof)
		    __ret = traits_type::not_eof(__i);
		  else if (!__testpb)
		    {
		      _M_create_pback();
		      _M_reading = true;
		      *this->gptr() = traits_type::to_char_type(__i);
		      __ret = __i;
		    }
		}
	      return __ret;
	    }
	
	  template<typename _CharT, typename _Traits>
	    typename basic_filebuf<_CharT, _Traits>::int_type
	    basic_filebuf<_CharT, _Traits>::
	    overflow(int_type __c)
	    {
	      int_type __ret = traits_type::eof();
	      const bool __testeof = traits_type::eq_int_type(__c, __ret);
	      const bool __testout = _M_mode & ios_base::out;
	      if (__testout)
		{
	          if (_M_reading)
	            {
	              _M_destroy_pback();
	              const int __gptr_off = _M_get_ext_pos(_M_state_last);
	              if (_M_seek(__gptr_off, ios_base::cur, _M_state_last)
	                  == pos_type(off_type(-1)))
	                return __ret;
	            }
		  if (this->pbase() < this->pptr())
		    {
		      // If appropriate, append the overflow char.
		      if (!__testeof)
			{
			  *this->pptr() = traits_type::to_char_type(__c);
			  this->pbump(1);
			}
	
		      // Convert pending sequence to external representation,
		      // and output.
		      if (_M_convert_to_external(this->pbase(),
						 this->pptr() - this->pbase()))
			{
			  _M_set_buffer(0);
			  __ret = traits_type::not_eof(__c);
			}
		    }
		  else if (_M_buf_size > 1)
		    {
		      // Overflow in 'uncommitted' mode: set _M_writing, set
		      // the buffer to the initial 'write' mode, and put __c
		      // into the buffer.
		      _M_set_buffer(0);
		      _M_writing = true;
		      if (!__testeof)
			{
			  *this->pptr() = traits_type::to_char_type(__c);
			  this->pbump(1);
			}
		      __ret = traits_type::not_eof(__c);
		    }
		  else
		    {
		      // Unbuffered.
		      char_type __conv = traits_type::to_char_type(__c);
		      if (__testeof || _M_convert_to_external(&__conv, 1))
			{
			  _M_writing = true;
			  __ret = traits_type::not_eof(__c);
			}
		    }
		}
	      return __ret;
	    }
	
	  template<typename _CharT, typename _Traits>
	    bool
	    basic_filebuf<_CharT, _Traits>::
	    _M_convert_to_external(_CharT* __ibuf, streamsize __ilen)
	    {
	      // Sizes of external and pending output.
	      streamsize __elen;
	      streamsize __plen;
	      if (__check_facet(_M_codecvt).always_noconv())
		{
		  __elen = _M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen);
		  __plen = __ilen;
		}
	      else
		{
		  // Worst-case number of external bytes needed.
		  // XXX Not done encoding() == -1.
		  streamsize __blen = __ilen * _M_codecvt->max_length();
		  char* __buf = static_cast<char*>(__builtin_alloca(__blen));
	
		  char* __bend;
		  const char_type* __iend;
		  codecvt_base::result __r;
		  __r = _M_codecvt->out(_M_state_cur, __ibuf, __ibuf + __ilen,
					__iend, __buf, __buf + __blen, __bend);
	
		  if (__r == codecvt_base::ok || __r == codecvt_base::partial)
		    __blen = __bend - __buf;
		  else if (__r == codecvt_base::noconv)
		    {
		      // Same as the always_noconv case above.
		      __buf = reinterpret_cast<char*>(__ibuf);
		      __blen = __ilen;
		    }
		  else
		    __throw_ios_failure(__N("basic_filebuf::_M_convert_to_external "
					    "conversion error"));
	  
		  __elen = _M_file.xsputn(__buf, __blen);
		  __plen = __blen;
	
		  // Try once more for partial conversions.
		  if (__r == codecvt_base::partial && __elen == __plen)
		    {
		      const char_type* __iresume = __iend;
		      streamsize __rlen = this->pptr() - __iend;
		      __r = _M_codecvt->out(_M_state_cur, __iresume,
					    __iresume + __rlen, __iend, __buf,
					    __buf + __blen, __bend);
		      if (__r != codecvt_base::error)
			{
			  __rlen = __bend - __buf;
			  __elen = _M_file.xsputn(__buf, __rlen);
			  __plen = __rlen;
			}
		      else
			__throw_ios_failure(__N("basic_filebuf::_M_convert_to_external "
						"conversion error"));
		    }
		}
	      return __elen == __plen;
	    }
	
	  template<typename _CharT, typename _Traits>
	    streamsize
	    basic_filebuf<_CharT, _Traits>::
	    xsgetn(_CharT* __s, streamsize __n)
	    {
	      // Clear out pback buffer before going on to the real deal...
	      streamsize __ret = 0;
	      if (_M_pback_init)
		{
		  if (__n > 0 && this->gptr() == this->eback())
		    {
		      *__s++ = *this->gptr(); // emulate non-underflowing sbumpc
		      this->gbump(1);
		      __ret = 1;
		      --__n;
		    }
		  _M_destroy_pback();
		}
	      else if (_M_writing)
		{
	 	  if (overflow() == traits_type::eof())
	 	    return __ret;
	 	  _M_set_buffer(-1);
	 	  _M_writing = false;
	 	}
	 
	      // Optimization in the always_noconv() case, to be generalized in the
	      // future: when __n > __buflen we read directly instead of using the
	      // buffer repeatedly.
	      const bool __testin = _M_mode & ios_base::in;
	      const streamsize __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1;
	 
	      if (__n > __buflen && __check_facet(_M_codecvt).always_noconv()
	 	   && __testin)
	 	 {
	 	   // First, copy the chars already present in the buffer.
	 	   const streamsize __avail = this->egptr() - this->gptr();
	 	   if (__avail != 0)
	 	     {
		       traits_type::copy(__s, this->gptr(), __avail);
	 	       __s += __avail;
		       this->setg(this->eback(), this->gptr() + __avail,
				  this->egptr());
		       __ret += __avail;
		       __n -= __avail;
	 	     }
	 
	 	   // Need to loop in case of short reads (relatively common
	 	   // with pipes).
	 	   streamsize __len;
	 	   for (;;)
	 	     {
	 	       __len = _M_file.xsgetn(reinterpret_cast<char*>(__s),
	 				      __n);
	 	       if (__len == -1)
	 		 __throw_ios_failure(__N("basic_filebuf::xsgetn "
	 					 "error reading the file"));
	 	       if (__len == 0)
	 		 break;
	 
	 	       __n -= __len;
	 	       __ret += __len;
	 	       if (__n == 0)
	 		 break;
	 
	 	       __s += __len;
	 	     }
	 
	 	   if (__n == 0)
	 	     {
	 	       _M_set_buffer(0);
	 	       _M_reading = true;
	 	     }
	 	   else if (__len == 0)
	 	     {
	 	       // If end of file is reached, set 'uncommitted'
	 	       // mode, thus allowing an immediate write without
	 	       // an intervening seek.
	 	       _M_set_buffer(-1);
	 	       _M_reading = false;
	 	     }
	 	 }
	      else
	 	 __ret += __streambuf_type::xsgetn(__s, __n);
	 
	      return __ret;
	    }
	
	  template<typename _CharT, typename _Traits>
	    streamsize
	    basic_filebuf<_CharT, _Traits>::
	    xsputn(const _CharT* __s, streamsize __n)
	    {
	      streamsize __ret = 0;
	      // Optimization in the always_noconv() case, to be generalized in the
	      // future: when __n is sufficiently large we write directly instead of
	      // using the buffer.
	      const bool __testout = _M_mode & ios_base::out;
	      if (__check_facet(_M_codecvt).always_noconv()
	 	   && __testout && !_M_reading)
		{
		  // Measurement would reveal the best choice.
		  const streamsize __chunk = 1ul << 10;
		  streamsize __bufavail = this->epptr() - this->pptr();
	
		  // Don't mistake 'uncommitted' mode buffered with unbuffered.
		  if (!_M_writing && _M_buf_size > 1)
		    __bufavail = _M_buf_size - 1;
	
		  const streamsize __limit = std::min(__chunk, __bufavail);
		  if (__n >= __limit)
		    {
		      const streamsize __buffill = this->pptr() - this->pbase();
		      const char* __buf = reinterpret_cast<const char*>(this->pbase());
		      __ret = _M_file.xsputn_2(__buf, __buffill,
					       reinterpret_cast<const char*>(__s),
					       __n);
		      if (__ret == __buffill + __n)
			{
			  _M_set_buffer(0);
			  _M_writing = true;
			}
		      if (__ret > __buffill)
			__ret -= __buffill;
		      else
			__ret = 0;
		    }
		  else
		    __ret = __streambuf_type::xsputn(__s, __n);
		}
	       else
		 __ret = __streambuf_type::xsputn(__s, __n);
	       return __ret;
	    }
	
	  template<typename _CharT, typename _Traits>
	    typename basic_filebuf<_CharT, _Traits>::__streambuf_type*
	    basic_filebuf<_CharT, _Traits>::
	    setbuf(char_type* __s, streamsize __n)
	    {
	      if (!this->is_open())
		{
		  if (__s == 0 && __n == 0)
		    _M_buf_size = 1;
		  else if (__s && __n > 0)
		    {
		      // This is implementation-defined behavior, and assumes that
		      // an external char_type array of length __n exists and has
		      // been pre-allocated. If this is not the case, things will
		      // quickly blow up. When __n > 1, __n - 1 positions will be
		      // used for the get area, __n - 1 for the put area and 1
		      // position to host the overflow char of a full put area.
		      // When __n == 1, 1 position will be used for the get area
		      // and 0 for the put area, as in the unbuffered case above.
		      _M_buf = __s;
		      _M_buf_size = __n;
		    }
		}
	      return this;
	    }
	
	
	  // According to 27.8.1.4 p11 - 13, seekoff should ignore the last
	  // argument (of type openmode).
	  template<typename _CharT, typename _Traits>
	    typename basic_filebuf<_CharT, _Traits>::pos_type
	    basic_filebuf<_CharT, _Traits>::
	    seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode)
	    {
	      int __width = 0;
	      if (_M_codecvt)
		__width = _M_codecvt->encoding();
	      if (__width < 0)
		__width = 0;
	
	      pos_type __ret = pos_type(off_type(-1));
	      const bool __testfail = __off != 0 && __width <= 0;
	      if (this->is_open() && !__testfail)
		{
		  // tellg and tellp queries do not affect any state, unless
		  // ! always_noconv and the put sequence is not empty.
		  // In that case, determining the position requires converting the
		  // put sequence. That doesn't use ext_buf, so requires a flush.
		  bool __no_movement = __way == ios_base::cur && __off == 0
		    && (!_M_writing || _M_codecvt->always_noconv());
	
		  // Ditch any pback buffers to avoid confusion.
		  if (!__no_movement)
		    _M_destroy_pback();
	
		  // Correct state at destination. Note that this is the correct
		  // state for the current position during output, because
		  // codecvt::unshift() returns the state to the initial state.
		  // This is also the correct state at the end of the file because
		  // an unshift sequence should have been written at the end.
		  __state_type __state = _M_state_beg;
		  off_type __computed_off = __off * __width;
		  if (_M_reading && __way == ios_base::cur)
		    {
		      __state = _M_state_last;
		      __computed_off += _M_get_ext_pos(__state);
		    }
		  if (!__no_movement)
		    __ret = _M_seek(__computed_off, __way, __state);
		  else
		    {
		      if (_M_writing)
			__computed_off = this->pptr() - this->pbase();
		      
	 	      off_type __file_off = _M_file.seekoff(0, ios_base::cur);
	 	      if (__file_off != off_type(-1))
			{
			  __ret = __file_off + __computed_off;
			  __ret.state(__state);
			}
		    }
		}
	      return __ret;
	    }
	
	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
	  // 171. Strange seekpos() semantics due to joint position
	  // According to the resolution of DR 171, seekpos should ignore the last
	  // argument (of type openmode).
	  template<typename _CharT, typename _Traits>
	    typename basic_filebuf<_CharT, _Traits>::pos_type
	    basic_filebuf<_CharT, _Traits>::
	    seekpos(pos_type __pos, ios_base::openmode)
	    {
	      pos_type __ret =  pos_type(off_type(-1));
	      if (this->is_open())
		{
		  // Ditch any pback buffers to avoid confusion.
		  _M_destroy_pback();
		  __ret = _M_seek(off_type(__pos), ios_base::beg, __pos.state());
		}
	      return __ret;
	    }
	
	  template<typename _CharT, typename _Traits>
	    typename basic_filebuf<_CharT, _Traits>::pos_type
	    basic_filebuf<_CharT, _Traits>::
	    _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state)
	    {
	      pos_type __ret = pos_type(off_type(-1));
	      if (_M_terminate_output())
		{
		  off_type __file_off = _M_file.seekoff(__off, __way);
		  if (__file_off != off_type(-1))
		    {
		      _M_reading = false;
		      _M_writing = false;
		      _M_ext_next = _M_ext_end = _M_ext_buf;
		      _M_set_buffer(-1);
		      _M_state_cur = __state;
		      __ret = __file_off;
		      __ret.state(_M_state_cur);
		    }
		}
	      return __ret;
	    }
	
	  // Returns the distance from the end of the ext buffer to the point
	  // corresponding to gptr(). This is a negative value. Updates __state
	  // from eback() correspondence to gptr().
	  template<typename _CharT, typename _Traits>
	    int basic_filebuf<_CharT, _Traits>::
	    _M_get_ext_pos(__state_type& __state)
	    {
	      if (_M_codecvt->always_noconv())
	        return this->gptr() - this->egptr();
	      else
	        {
	          // Calculate offset from _M_ext_buf that corresponds to
	          // gptr(). Precondition: __state == _M_state_last, which
	          // corresponds to eback().
	          const int __gptr_off =
	            _M_codecvt->length(__state, _M_ext_buf, _M_ext_next,
	                               this->gptr() - this->eback());
	          return _M_ext_buf + __gptr_off - _M_ext_end;
	        }
	    }
	    
	  template<typename _CharT, typename _Traits>
	    bool
	    basic_filebuf<_CharT, _Traits>::
	    _M_terminate_output()
	    {
	      // Part one: update the output sequence.
	      bool __testvalid = true;
	      if (this->pbase() < this->pptr())
		{
		  const int_type __tmp = this->overflow();
		  if (traits_type::eq_int_type(__tmp, traits_type::eof()))
		    __testvalid = false;
		}
	
	      // Part two: output unshift sequence.
	      if (_M_writing && !__check_facet(_M_codecvt).always_noconv()
		  && __testvalid)
		{
		  // Note: this value is arbitrary, since there is no way to
		  // get the length of the unshift sequence from codecvt,
		  // without calling unshift.
		  const size_t __blen = 128;
		  char __buf[__blen];
		  codecvt_base::result __r;
		  streamsize __ilen = 0;
	
		  do
		    {
		      char* __next;
		      __r = _M_codecvt->unshift(_M_state_cur, __buf,
						__buf + __blen, __next);
		      if (__r == codecvt_base::error)
			__testvalid = false;
		      else if (__r == codecvt_base::ok ||
			       __r == codecvt_base::partial)
			{
			  __ilen = __next - __buf;
			  if (__ilen > 0)
			    {
			      const streamsize __elen = _M_file.xsputn(__buf, __ilen);
			      if (__elen != __ilen)
				__testvalid = false;
			    }
			}
		    }
		  while (__r == codecvt_base::partial && __ilen > 0 && __testvalid);
	
		  if (__testvalid)
		    {
		      // This second call to overflow() is required by the standard,
		      // but it's not clear why it's needed, since the output buffer
		      // should be empty by this point (it should have been emptied
		      // in the first call to overflow()).
		      const int_type __tmp = this->overflow();
		      if (traits_type::eq_int_type(__tmp, traits_type::eof()))
			__testvalid = false;
		    }
		}
	      return __testvalid;
	    }
	
	  template<typename _CharT, typename _Traits>
	    int
	    basic_filebuf<_CharT, _Traits>::
	    sync()
	    {
	      // Make sure that the internal buffer resyncs its idea of
	      // the file position with the external file.
	      int __ret = 0;
	      if (this->pbase() < this->pptr())
		{
		  const int_type __tmp = this->overflow();
		  if (traits_type::eq_int_type(__tmp, traits_type::eof()))
		    __ret = -1;
		}
	      return __ret;
	    }
	
	  template<typename _CharT, typename _Traits>
	    void
	    basic_filebuf<_CharT, _Traits>::
	    imbue(const locale& __loc)
	    {
	      bool __testvalid = true;
	
	      const __codecvt_type* _M_codecvt_tmp = 0;
	      if (__builtin_expect(has_facet<__codecvt_type>(__loc), true))
		_M_codecvt_tmp = &use_facet<__codecvt_type>(__loc);
	
	      if (this->is_open())
		{
		  // encoding() == -1 is ok only at the beginning.
		  if ((_M_reading || _M_writing)
		      && __check_facet(_M_codecvt).encoding() == -1)
		    __testvalid = false;
		  else
		    {
		      if (_M_reading)
			{
			  if (__check_facet(_M_codecvt).always_noconv())
			    {
			      if (_M_codecvt_tmp
				  && !__check_facet(_M_codecvt_tmp).always_noconv())
				__testvalid = this->seekoff(0, ios_base::cur, _M_mode)
				              != pos_type(off_type(-1));
			    }
			  else
			    {
			      // External position corresponding to gptr().
			      _M_ext_next = _M_ext_buf
				+ _M_codecvt->length(_M_state_last, _M_ext_buf,
						     _M_ext_next,
						     this->gptr() - this->eback());
			      const streamsize __remainder = _M_ext_end - _M_ext_next;
			      if (__remainder)
				__builtin_memmove(_M_ext_buf, _M_ext_next, __remainder);
	
			      _M_ext_next = _M_ext_buf;
			      _M_ext_end = _M_ext_buf + __remainder;
			      _M_set_buffer(-1);
			      _M_state_last = _M_state_cur = _M_state_beg;
			    }
			}
		      else if (_M_writing && (__testvalid = _M_terminate_output()))
			_M_set_buffer(-1);
		    }
		}
	
	      if (__testvalid)
		_M_codecvt = _M_codecvt_tmp;
	      else
		_M_codecvt = 0;
	    }
	
	  // Inhibit implicit instantiations for required instantiations,
	  // which are defined via explicit instantiations elsewhere.
	#if _GLIBCXX_EXTERN_TEMPLATE
	  extern template class basic_filebuf<char>;
	  extern template class basic_ifstream<char>;
	  extern template class basic_ofstream<char>;
	  extern template class basic_fstream<char>;
	
	#ifdef _GLIBCXX_USE_WCHAR_T
	  extern template class basic_filebuf<wchar_t>;
	  extern template class basic_ifstream<wchar_t>;
	  extern template class basic_ofstream<wchar_t>;
	  extern template class basic_fstream<wchar_t>;
	#endif
	#endif
	
	_GLIBCXX_END_NAMESPACE_VERSION
	} // namespace std
	
	#endif