[gcc.git] / libstdc++-v3 / include / bits / fstream.tcc

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

// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003
// 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 2, 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.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING.  If not, write to the Free
// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

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

#ifndef _CPP_BITS_FSTREAM_TCC
#define _CPP_BITS_FSTREAM_TCC 1

#pragma GCC system_header

namespace std
{
  template<typename _CharT, typename _Traits>
    void
    basic_filebuf<_CharT, _Traits>::
    _M_allocate_internal_buffer()
    {
      if (!this->_M_buf && this->_M_buf_size_opt)
	{
	  this->_M_buf_size = this->_M_buf_size_opt;

	  // Allocate internal buffer...
	  this->_M_buf = new char_type[this->_M_buf_size];
	  // ... and consistently set the end of buffer pointer.
	  this->_M_out_end = this->_M_buf + this->_M_buf_size;
	  _M_buf_allocated = true;
	}
    }

  // Both close and setbuf need to deallocate internal buffers, if it exists.
  template<typename _CharT, typename _Traits>
    void
    basic_filebuf<_CharT, _Traits>::
    _M_destroy_internal_buffer()
    {
      if (_M_buf_allocated)
	{
	  delete [] this->_M_buf;
	  this->_M_buf = NULL;
	  _M_buf_allocated = false;
	  this->setg(NULL, NULL, NULL);
	  this->setp(NULL, NULL);
	}
    }

  template<typename _CharT, typename _Traits>
    basic_filebuf<_CharT, _Traits>::
    basic_filebuf() : __streambuf_type(), _M_file(&_M_lock), 
    _M_state_cur(__state_type()), _M_state_beg(__state_type()), 
    _M_buf_allocated(false), _M_last_overflowed(false)
    { this->_M_buf_unified = true; }

  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 = NULL;
      if (!this->is_open())
	{
	  _M_file.open(__s, __mode);
	  if (this->is_open())
	    {
	      _M_allocate_internal_buffer();
	      this->_M_mode = __mode;

	      // Setup initial position of buffer.
	      _M_set_indeterminate();

	      // Set input buffer to something real.
	      // NB: Must open in non-blocking way to do this, or must
	      // set the initial position in a different manner than
	      // using underflow.
 	      if (__mode & ios_base::in && _M_buf_allocated)
 		this->underflow();

	      if ((__mode & ios_base::ate)
		  && this->seekoff(0, ios_base::end, __mode) < 0)
		{
		  // 27.8.1.3,4
		  this->close();
		  return __ret;
		}

	      __ret = this;
	    }
	}
      return __ret;
    }

  template<typename _CharT, typename _Traits>
    typename basic_filebuf<_CharT, _Traits>::__filebuf_type* 
    basic_filebuf<_CharT, _Traits>::
    close()
    {
      __filebuf_type* __ret = NULL;
      if (this->is_open())
	{
	  bool __testfail = false;
	  const int_type __eof = traits_type::eof();
	  bool __testput = this->_M_out_cur
	                   && this->_M_out_beg < this->_M_out_lim;
	  if (__testput 
	      && traits_type::eq_int_type(_M_really_overflow(__eof), __eof))
	    __testfail = true;

#if 0
	  // XXX not done
	  if (_M_last_overflowed)
	    {
	      _M_output_unshift();
	      _M_really_overflow(__eof);
	    }
#endif

	  // NB: Do this here so that re-opened filebufs will be cool...
	  this->_M_mode = ios_base::openmode(0);
	  _M_destroy_internal_buffer();
	  _M_pback_destroy();

	  if (!_M_file.close())
	    __testfail = true;

	  if (!__testfail)
	    __ret = this;
	}
      _M_last_overflowed = false;	
      return __ret;
    }

  template<typename _CharT, typename _Traits>
    streamsize 
    basic_filebuf<_CharT, _Traits>::
    showmanyc()
    {
      streamsize __ret = -1;
      bool __testin = this->_M_mode & ios_base::in;

      if (__testin && this->is_open())
	__ret = this->_M_in_end - this->_M_in_cur;
      _M_last_overflowed = false;	
      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();
      bool __testin = this->_M_mode & ios_base::in;

      if (__testin)
	{
	  bool __testpb = this->_M_in_beg < this->_M_in_cur;
	  char_type __c = traits_type::to_char_type(__i);
	  bool __testeof = traits_type::eq_int_type(__i, __ret);

	  if (__testpb)
	    {
	      bool __testout = this->_M_mode & ios_base::out;
	      bool __testeq = traits_type::eq(__c, this->gptr()[-1]);

	      // Try to put back __c into input sequence in one of three ways.
	      // Order these tests done in is unspecified by the standard.
	      if (!__testeof && __testeq)
		{
		  --this->_M_in_cur;
		  if (__testout)
		    --this->_M_out_cur;
		  __ret = __i;
		}
	      else if (__testeof)
		{
		  --this->_M_in_cur;
		  if (__testout)
		    --this->_M_out_cur;
		  __ret = traits_type::not_eof(__i);
		}
	      else if (!__testeof)
		{
		  --this->_M_in_cur;
		  if (__testout)
		    --this->_M_out_cur;
		  _M_pback_create();
		  *this->_M_in_cur = __c; 
		  __ret = __i;
		}
	    }
	  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()
	      if (this->seekoff(-1, ios_base::cur) >= 0)
		{
		  this->underflow();
		  if (!__testeof)
		    {
		      if (!traits_type::eq(__c, *this->_M_in_cur))
			{
			  _M_pback_create();
			  *this->_M_in_cur = __c;
			}
		      __ret = __i;
		    }
		  else
		    __ret = traits_type::not_eof(__i);
		}
 	    }
	}
      _M_last_overflowed = false;	
      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();
      bool __testput = _M_out_buf_size();
      bool __testout = this->_M_mode & ios_base::out;
      
      if (__testout)
	{
	  if (traits_type::eq_int_type(__c, traits_type::eof()))
	    __ret = traits_type::not_eof(__c);
	  else if (__testput)
	    {
	      *this->_M_out_cur = traits_type::to_char_type(__c);
	      _M_out_cur_move(1);
	      __ret = traits_type::not_eof(__c);
	    }
	  else 
	    __ret = this->_M_really_overflow(__c);
	}

      _M_last_overflowed = false;    // Set in _M_really_overflow, below.
      return __ret;
    }
  
  template<typename _CharT, typename _Traits>
    void
    basic_filebuf<_CharT, _Traits>::
    _M_convert_to_external(_CharT* __ibuf, streamsize __ilen,
			   streamsize& __elen, streamsize& __plen)
    {
      const locale __loc = this->getloc();
      const __codecvt_type& __cvt = use_facet<__codecvt_type>(__loc);
      // Sync with stdio.
      bool __sync = this->_M_buf_size == 1;

      if (__cvt.always_noconv() && __ilen)
	{
	  __elen +=
	    _M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen, __sync);
	  __plen += __ilen;
	}
      else
	{
	  // Worst-case number of external bytes needed.
	  int __ext_multiplier = __cvt.encoding();
	  if (__ext_multiplier ==  -1 || __ext_multiplier == 0)
	    __ext_multiplier = sizeof(char_type);
	  streamsize __blen = __ilen * __ext_multiplier;
	  char* __buf = static_cast<char*>(__builtin_alloca(__blen));
	  char* __bend;
	  const char_type* __iend;
	  __res_type __r = __cvt.out(_M_state_cur, __ibuf, __ibuf + __ilen, 
		 		     __iend, __buf, __buf + __blen, __bend);

	  if (__r == codecvt_base::ok || __r == codecvt_base::partial)
	    __blen = __bend - __buf;
	  // Similarly to the always_noconv case above.
	  else if (__r == codecvt_base::noconv)
	    {
	      __buf = reinterpret_cast<char*>(__ibuf);
	      __blen = __ilen;
	    }
	  // Result == error
	  else 
	    __blen = 0;
	  
	  if (__blen)
	    {
	      __elen += _M_file.xsputn(__buf, __blen, __sync);
	      __plen += __blen;
	    }

	  // Try once more for partial conversions.
	  if (__r == codecvt_base::partial)
	    {
	      const char_type* __iresume = __iend;
	      streamsize __rlen = this->_M_out_lim - __iend;
	      __r = __cvt.out(_M_state_cur, __iresume, __iresume + __rlen, 
			      __iend, __buf, __buf + __blen, __bend);
	      if (__r != codecvt_base::error)
		__rlen = __bend - __buf;
	      else
		{
		  __rlen = 0;
		  // Signal to the caller (_M_really_overflow) that
		  // codecvt::out eventually failed.
		  __elen = 0;		  
		}
	      if (__rlen)
		{
		  __elen += _M_file.xsputn(__buf, __rlen, __sync);
		  __plen += __rlen;
		}
	    }
	}
    }

  template<typename _CharT, typename _Traits>
    typename basic_filebuf<_CharT, _Traits>::int_type 
    basic_filebuf<_CharT, _Traits>::
    _M_really_overflow(int_type __c)
    {
      int_type __ret = traits_type::eof();
      bool __testput = this->_M_out_cur && this->_M_out_beg < this->_M_out_lim;
      bool __testunbuffered = _M_file.is_open() && !this->_M_buf_size_opt;
      // Sync with stdio.
      bool __sync = this->_M_buf_size == 1;

      if (__testput || __testunbuffered)
	{
	  // Sizes of external and pending output.
	  streamsize __elen = 0;
	  streamsize __plen = 0;

	  // Need to restore current position. The position of the external
	  // byte sequence (_M_file) corresponds to _M_filepos, and we need
	  // to move it to _M_out_beg for the write.
	  if (_M_filepos && _M_filepos != this->_M_out_beg)
	    {
	      off_type __off = this->_M_out_beg - _M_filepos;
	      _M_file.seekoff(__off, ios_base::cur, __sync);
	    }

	  // Convert internal buffer to external representation, output.
	  // NB: In the unbuffered case, no internal buffer exists. 
	  if (!__testunbuffered)
	    _M_convert_to_external(this->_M_out_beg,
				   this->_M_out_lim - this->_M_out_beg, 
				   __elen, __plen);

	  // Checks for codecvt.out failures and _M_file.xsputn failures,
	  // respectively, inside _M_convert_to_external.
	  if (__testunbuffered || (__elen && __elen == __plen))
	    {
	      // Convert pending sequence to external representation, output.
	      // If eof, then just attempt sync.
	      if (!traits_type::eq_int_type(__c, traits_type::eof()))
		{
		  char_type __pending = traits_type::to_char_type(__c);
		  _M_convert_to_external(&__pending, 1, __elen, __plen);

		  // User code must flush when switching modes (thus don't sync).
		  if (__elen == __plen && __elen)
		    {
		      _M_set_indeterminate();
		      __ret = traits_type::not_eof(__c);
		    }
		}
	      else if (!_M_file.sync())
		{
		  _M_set_indeterminate();
		  __ret = traits_type::not_eof(__c);
		}
	    }
	}
      _M_last_overflowed = true;	
      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() && __s == 0 && __n == 0)
	this->_M_buf_size_opt = 0;
      else if (__s && __n)
	{
	  // This is implementation-defined behavior, and assumes
	  // that an external char_type array of length (__s + __n)
	  // exists and has been pre-allocated. If this is not the
	  // case, things will quickly blow up.

	  // Step 1: Destroy the current internal array.
	  _M_destroy_internal_buffer();
	  
	  // Step 2: Use the external array.
	  this->_M_buf = __s;
	  this->_M_buf_size_opt = this->_M_buf_size = __n;
	  // Consistently set the end of buffer pointer.
	  this->_M_out_end = this->_M_buf + this->_M_buf_size;
	  _M_set_indeterminate();
	}
      _M_last_overflowed = false;	
      return this; 
    }
  
  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 __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;
      // Sync with stdio.
      bool __sync = this->_M_buf_size == 1;
      
      // Should probably do has_facet checks here.
      int __width = use_facet<__codecvt_type>(this->_M_buf_locale).encoding();
      if (__width < 0)
	__width = 0;
      bool __testfail = __off != 0 && __width <= 0;
      
      if (this->is_open() && !__testfail && (__testin || __testout)) 
	{
	  // Ditch any pback buffers to avoid confusion.
	  _M_pback_destroy();

	  if (__way != ios_base::cur || __off != 0)
	    { 
	      off_type __computed_off = __width * __off;
	      
	      bool __testget = this->_M_in_cur
		&& this->_M_in_beg < this->_M_in_end;
	      bool __testput = this->_M_out_cur
		&& this->_M_out_beg < this->_M_out_lim;
	      // Sync the internal and external streams.
	      // out
	      if (__testput || _M_last_overflowed)
		{
		  // Part one: update the output sequence.
		  this->sync();
		  // Part two: output unshift sequence.
		  _M_output_unshift();
		}
	      //in
	      else if (__testget && __way == ios_base::cur)
		__computed_off += this->_M_in_cur - _M_filepos;

	      // Return pos_type(off_type(-1)) in case of failure.
	      __ret = _M_file.seekoff(__computed_off, __way, __sync, __mode);
	      _M_set_indeterminate();
	    }
	  // NB: Need to do this in case _M_file in indeterminate
	  // state, ie _M_file._offset == -1
	  else
	    {
	      pos_type __tmp =
		_M_file.seekoff(__off, ios_base::cur,
				__sync, __mode);
	      if (__tmp >= 0)
		{
		  // Seek successful.
		  __ret = __tmp;
		  __ret +=
		    std::max(this->_M_out_cur, this->_M_in_cur) - _M_filepos;
		}
	    }
	}
      _M_last_overflowed = false;	
      return __ret;
    }

  template<typename _CharT, typename _Traits>
    typename basic_filebuf<_CharT, _Traits>::pos_type
    basic_filebuf<_CharT, _Traits>::
    seekpos(pos_type __pos, ios_base::openmode __mode)
    {
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
// 171. Strange seekpos() semantics due to joint position
      return this->seekoff(off_type(__pos), ios_base::beg, __mode);
#endif
    }

  template<typename _CharT, typename _Traits>
    void 
    basic_filebuf<_CharT, _Traits>::
    _M_output_unshift()
    { }

  template<typename _CharT, typename _Traits>
    void
    basic_filebuf<_CharT, _Traits>::
    imbue(const locale& __loc)
    {
      bool __testbeg = gptr() == eback() && pptr() == pbase();

      if (__testbeg && this->_M_buf_locale != __loc)
	this->_M_buf_locale = __loc;

      // NB this may require the reconversion of previously
      // converted chars. This in turn may cause the reconstruction
      // of the original file. YIKES!!
      // XXX The part in the above comment is not done.
      _M_last_overflowed = false;	
    }

  // Inhibit implicit instantiations for required instantiations,
  // which are defined via explicit instantiations elsewhere.  
  // NB:  This syntax is a GNU extension.
#if _GLIBCPP_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 _GLIBCPP_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
} // namespace std

#endif
Commit	Line	Data
	1	// File based streams -- C++ --
	2
	3	// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003
	4	// Free Software Foundation, Inc.
	5	//
	6	// This file is part of the GNU ISO C++ Library. This library is free
	7	// software; you can redistribute it and/or modify it under the
	8	// terms of the GNU General Public License as published by the
	9	// Free Software Foundation; either version 2, or (at your option)
	10	// any later version.
	11
	12	// This library is distributed in the hope that it will be useful,
	13	// but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	// GNU General Public License for more details.
	16
	17	// You should have received a copy of the GNU General Public License along
	18	// with this library; see the file COPYING. If not, write to the Free
	19	// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
	20	// USA.
	21
	22	// As a special exception, you may use this file as part of a free software
	23	// library without restriction. Specifically, if other files instantiate
	24	// templates or use macros or inline functions from this file, or you compile
	25	// this file and link it with other files to produce an executable, this
	26	// file does not by itself cause the resulting executable to be covered by
	27	// the GNU General Public License. This exception does not however
	28	// invalidate any other reasons why the executable file might be covered by
	29	// the GNU General Public License.
	30
	31	//
	32	// ISO C++ 14882: 27.8 File-based streams
	33	//
	34
	35	#ifndef _CPP_BITS_FSTREAM_TCC
	36	#define _CPP_BITS_FSTREAM_TCC 1
	37
	38	#pragma GCC system_header
	39
	40	namespace std
	41	{
	42	template<typename _CharT, typename _Traits>
	43	void
	44	basic_filebuf<_CharT, _Traits>::
	45	_M_allocate_internal_buffer()
	46	{
	47	if (!this->_M_buf && this->_M_buf_size_opt)
	48	{
	49	this->_M_buf_size = this->_M_buf_size_opt;
	50
	51	// Allocate internal buffer...
	52	this->_M_buf = new char_type[this->_M_buf_size];
	53	// ... and consistently set the end of buffer pointer.
	54	this->_M_out_end = this->_M_buf + this->_M_buf_size;
	55	_M_buf_allocated = true;
	56	}
	57	}
	58
	59	// Both close and setbuf need to deallocate internal buffers, if it exists.
	60	template<typename _CharT, typename _Traits>
	61	void
	62	basic_filebuf<_CharT, _Traits>::
	63	_M_destroy_internal_buffer()
	64	{
	65	if (_M_buf_allocated)
	66	{
	67	delete [] this->_M_buf;
	68	this->_M_buf = NULL;
	69	_M_buf_allocated = false;
	70	this->setg(NULL, NULL, NULL);
	71	this->setp(NULL, NULL);
	72	}
	73	}
	74
	75	template<typename _CharT, typename _Traits>
	76	basic_filebuf<_CharT, _Traits>::
	77	basic_filebuf() : __streambuf_type(), _M_file(&_M_lock),
	78	_M_state_cur(__state_type()), _M_state_beg(__state_type()),
	79	_M_buf_allocated(false), _M_last_overflowed(false)
	80	{ this->_M_buf_unified = true; }
	81
	82	template<typename _CharT, typename _Traits>
	83	typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
	84	basic_filebuf<_CharT, _Traits>::
	85	open(const char* __s, ios_base::openmode __mode)
	86	{
	87	__filebuf_type *__ret = NULL;
	88	if (!this->is_open())
	89	{
	90	_M_file.open(__s, __mode);
	91	if (this->is_open())
	92	{
	93	_M_allocate_internal_buffer();
	94	this->_M_mode = __mode;
	95
	96	// Setup initial position of buffer.
	97	_M_set_indeterminate();
	98
	99	// Set input buffer to something real.
	100	// NB: Must open in non-blocking way to do this, or must
	101	// set the initial position in a different manner than
	102	// using underflow.
	103	if (__mode & ios_base::in && _M_buf_allocated)
	104	this->underflow();
	105
	106	if ((__mode & ios_base::ate)
	107	&& this->seekoff(0, ios_base::end, __mode) < 0)
	108	{
	109	// 27.8.1.3,4
	110	this->close();
	111	return __ret;
	112	}
	113
	114	__ret = this;
	115	}
	116	}
	117	return __ret;
	118	}
	119
	120	template<typename _CharT, typename _Traits>
	121	typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
	122	basic_filebuf<_CharT, _Traits>::
	123	close()
	124	{
	125	__filebuf_type* __ret = NULL;
	126	if (this->is_open())
	127	{
	128	bool __testfail = false;
	129	const int_type __eof = traits_type::eof();
	130	bool __testput = this->_M_out_cur
	131	&& this->_M_out_beg < this->_M_out_lim;
	132	if (__testput
	133	&& traits_type::eq_int_type(_M_really_overflow(__eof), __eof))
	134	__testfail = true;
	135
	136	#if 0
	137	// XXX not done
	138	if (_M_last_overflowed)
	139	{
	140	_M_output_unshift();
	141	_M_really_overflow(__eof);
	142	}
	143	#endif
	144
	145	// NB: Do this here so that re-opened filebufs will be cool...
	146	this->_M_mode = ios_base::openmode(0);
	147	_M_destroy_internal_buffer();
	148	_M_pback_destroy();
	149
	150	if (!_M_file.close())
	151	__testfail = true;
	152
	153	if (!__testfail)
	154	__ret = this;
	155	}
	156	_M_last_overflowed = false;
	157	return __ret;
	158	}
	159
	160	template<typename _CharT, typename _Traits>
	161	streamsize
	162	basic_filebuf<_CharT, _Traits>::
	163	showmanyc()
	164	{
	165	streamsize __ret = -1;
	166	bool __testin = this->_M_mode & ios_base::in;
	167
	168	if (__testin && this->is_open())
	169	__ret = this->_M_in_end - this->_M_in_cur;
	170	_M_last_overflowed = false;
	171	return __ret;
	172	}
	173
	174	template<typename _CharT, typename _Traits>
	175	typename basic_filebuf<_CharT, _Traits>::int_type
	176	basic_filebuf<_CharT, _Traits>::
	177	pbackfail(int_type __i)
	178	{
	179	int_type __ret = traits_type::eof();
	180	bool __testin = this->_M_mode & ios_base::in;
	181
	182	if (__testin)
	183	{
	184	bool __testpb = this->_M_in_beg < this->_M_in_cur;
	185	char_type __c = traits_type::to_char_type(__i);
	186	bool __testeof = traits_type::eq_int_type(__i, __ret);
	187
	188	if (__testpb)
	189	{
	190	bool __testout = this->_M_mode & ios_base::out;
	191	bool __testeq = traits_type::eq(__c, this->gptr()[-1]);
	192
	193	// Try to put back __c into input sequence in one of three ways.
	194	// Order these tests done in is unspecified by the standard.
	195	if (!__testeof && __testeq)
	196	{
	197	--this->_M_in_cur;
	198	if (__testout)
	199	--this->_M_out_cur;
	200	__ret = __i;
	201	}
	202	else if (__testeof)
	203	{
	204	--this->_M_in_cur;
	205	if (__testout)
	206	--this->_M_out_cur;
	207	__ret = traits_type::not_eof(__i);
	208	}
	209	else if (!__testeof)
	210	{
	211	--this->_M_in_cur;
	212	if (__testout)
	213	--this->_M_out_cur;
	214	_M_pback_create();
	215	*this->_M_in_cur = __c;
	216	__ret = __i;
	217	}
	218	}
	219	else
	220	{
	221	// At the beginning of the buffer, need to make a
	222	// putback position available.
	223	// But the seek may fail (f.i., at the beginning of
	224	// a file, see libstdc++/9439) and in that case
	225	// we return traits_type::eof()
	226	if (this->seekoff(-1, ios_base::cur) >= 0)
	227	{
	228	this->underflow();
	229	if (!__testeof)
	230	{
	231	if (!traits_type::eq(__c, *this->_M_in_cur))
	232	{
	233	_M_pback_create();
	234	*this->_M_in_cur = __c;
	235	}
	236	__ret = __i;
	237	}
	238	else
	239	__ret = traits_type::not_eof(__i);
	240	}
	241	}
	242	}
	243	_M_last_overflowed = false;
	244	return __ret;
	245	}
	246
	247	template<typename _CharT, typename _Traits>
	248	typename basic_filebuf<_CharT, _Traits>::int_type
	249	basic_filebuf<_CharT, _Traits>::
	250	overflow(int_type __c)
	251	{
	252	int_type __ret = traits_type::eof();
	253	bool __testput = _M_out_buf_size();
	254	bool __testout = this->_M_mode & ios_base::out;
	255
	256	if (__testout)
	257	{
	258	if (traits_type::eq_int_type(__c, traits_type::eof()))
	259	__ret = traits_type::not_eof(__c);
	260	else if (__testput)
	261	{
	262	*this->_M_out_cur = traits_type::to_char_type(__c);
	263	_M_out_cur_move(1);
	264	__ret = traits_type::not_eof(__c);
	265	}
	266	else
	267	__ret = this->_M_really_overflow(__c);
	268	}
	269
	270	_M_last_overflowed = false; // Set in _M_really_overflow, below.
	271	return __ret;
	272	}
	273
	274	template<typename _CharT, typename _Traits>
	275	void
	276	basic_filebuf<_CharT, _Traits>::
	277	_M_convert_to_external(_CharT* __ibuf, streamsize __ilen,
	278	streamsize& __elen, streamsize& __plen)
	279	{
	280	const locale __loc = this->getloc();
	281	const __codecvt_type& __cvt = use_facet<__codecvt_type>(__loc);
	282	// Sync with stdio.
	283	bool __sync = this->_M_buf_size == 1;
	284
	285	if (__cvt.always_noconv() && __ilen)
	286	{
	287	__elen +=
	288	_M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen, __sync);
	289	__plen += __ilen;
	290	}
	291	else
	292	{
	293	// Worst-case number of external bytes needed.
	294	int __ext_multiplier = __cvt.encoding();
	295	if (__ext_multiplier == -1 \|\| __ext_multiplier == 0)
	296	__ext_multiplier = sizeof(char_type);
	297	streamsize __blen = __ilen * __ext_multiplier;
	298	char* __buf = static_cast<char*>(__builtin_alloca(__blen));
	299	char* __bend;
	300	const char_type* __iend;
	301	__res_type __r = __cvt.out(_M_state_cur, __ibuf, __ibuf + __ilen,
	302	__iend, __buf, __buf + __blen, __bend);
	303
	304	if (__r == codecvt_base::ok \|\| __r == codecvt_base::partial)
	305	__blen = __bend - __buf;
	306	// Similarly to the always_noconv case above.
	307	else if (__r == codecvt_base::noconv)
	308	{
	309	__buf = reinterpret_cast<char*>(__ibuf);
	310	__blen = __ilen;
	311	}
	312	// Result == error
	313	else
	314	__blen = 0;
	315
	316	if (__blen)
	317	{
	318	__elen += _M_file.xsputn(__buf, __blen, __sync);
	319	__plen += __blen;
	320	}
	321
	322	// Try once more for partial conversions.
	323	if (__r == codecvt_base::partial)
	324	{
	325	const char_type* __iresume = __iend;
	326	streamsize __rlen = this->_M_out_lim - __iend;
	327	__r = __cvt.out(_M_state_cur, __iresume, __iresume + __rlen,
	328	__iend, __buf, __buf + __blen, __bend);
	329	if (__r != codecvt_base::error)
	330	__rlen = __bend - __buf;
	331	else
	332	{
	333	__rlen = 0;
	334	// Signal to the caller (_M_really_overflow) that
	335	// codecvt::out eventually failed.
	336	__elen = 0;
	337	}
	338	if (__rlen)
	339	{
	340	__elen += _M_file.xsputn(__buf, __rlen, __sync);
	341	__plen += __rlen;
	342	}
	343	}
	344	}
	345	}
	346
	347	template<typename _CharT, typename _Traits>
	348	typename basic_filebuf<_CharT, _Traits>::int_type
	349	basic_filebuf<_CharT, _Traits>::
	350	_M_really_overflow(int_type __c)
	351	{
	352	int_type __ret = traits_type::eof();
	353	bool __testput = this->_M_out_cur && this->_M_out_beg < this->_M_out_lim;
	354	bool __testunbuffered = _M_file.is_open() && !this->_M_buf_size_opt;
	355	// Sync with stdio.
	356	bool __sync = this->_M_buf_size == 1;
	357
	358	if (__testput \|\| __testunbuffered)
	359	{
	360	// Sizes of external and pending output.
	361	streamsize __elen = 0;
	362	streamsize __plen = 0;
	363
	364	// Need to restore current position. The position of the external
	365	// byte sequence (_M_file) corresponds to _M_filepos, and we need
	366	// to move it to _M_out_beg for the write.
	367	if (_M_filepos && _M_filepos != this->_M_out_beg)
	368	{
	369	off_type __off = this->_M_out_beg - _M_filepos;
	370	_M_file.seekoff(__off, ios_base::cur, __sync);
	371	}
	372
	373	// Convert internal buffer to external representation, output.
	374	// NB: In the unbuffered case, no internal buffer exists.
	375	if (!__testunbuffered)
	376	_M_convert_to_external(this->_M_out_beg,
	377	this->_M_out_lim - this->_M_out_beg,
	378	__elen, __plen);
	379
	380	// Checks for codecvt.out failures and _M_file.xsputn failures,
	381	// respectively, inside _M_convert_to_external.
	382	if (__testunbuffered \|\| (__elen && __elen == __plen))
	383	{
	384	// Convert pending sequence to external representation, output.
	385	// If eof, then just attempt sync.
	386	if (!traits_type::eq_int_type(__c, traits_type::eof()))
	387	{
	388	char_type __pending = traits_type::to_char_type(__c);
	389	_M_convert_to_external(&__pending, 1, __elen, __plen);
	390
	391	// User code must flush when switching modes (thus don't sync).
	392	if (__elen == __plen && __elen)
	393	{
	394	_M_set_indeterminate();
	395	__ret = traits_type::not_eof(__c);
	396	}
	397	}
	398	else if (!_M_file.sync())
	399	{
	400	_M_set_indeterminate();
	401	__ret = traits_type::not_eof(__c);
	402	}
	403	}
	404	}
	405	_M_last_overflowed = true;
	406	return __ret;
	407	}
	408
	409	template<typename _CharT, typename _Traits>
	410	typename basic_filebuf<_CharT, _Traits>::__streambuf_type*
	411	basic_filebuf<_CharT, _Traits>::
	412	setbuf(char_type* __s, streamsize __n)
	413	{
	414	if (!this->is_open() && __s == 0 && __n == 0)
	415	this->_M_buf_size_opt = 0;
	416	else if (__s && __n)
	417	{
	418	// This is implementation-defined behavior, and assumes
	419	// that an external char_type array of length (__s + __n)
	420	// exists and has been pre-allocated. If this is not the
	421	// case, things will quickly blow up.
	422
	423	// Step 1: Destroy the current internal array.
	424	_M_destroy_internal_buffer();
	425
	426	// Step 2: Use the external array.
	427	this->_M_buf = __s;
	428	this->_M_buf_size_opt = this->_M_buf_size = __n;
	429	// Consistently set the end of buffer pointer.
	430	this->_M_out_end = this->_M_buf + this->_M_buf_size;
	431	_M_set_indeterminate();
	432	}
	433	_M_last_overflowed = false;
	434	return this;
	435	}
	436
	437	template<typename _CharT, typename _Traits>
	438	typename basic_filebuf<_CharT, _Traits>::pos_type
	439	basic_filebuf<_CharT, _Traits>::
	440	seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode)
	441	{
	442	pos_type __ret = pos_type(off_type(-1));
	443	bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
	444	bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
	445	// Sync with stdio.
	446	bool __sync = this->_M_buf_size == 1;
	447
	448	// Should probably do has_facet checks here.
	449	int __width = use_facet<__codecvt_type>(this->_M_buf_locale).encoding();
	450	if (__width < 0)
	451	__width = 0;
	452	bool __testfail = __off != 0 && __width <= 0;
	453
	454	if (this->is_open() && !__testfail && (__testin \|\| __testout))
	455	{
	456	// Ditch any pback buffers to avoid confusion.
	457	_M_pback_destroy();
	458
	459	if (__way != ios_base::cur \|\| __off != 0)
	460	{
	461	off_type __computed_off = __width * __off;
	462
	463	bool __testget = this->_M_in_cur
	464	&& this->_M_in_beg < this->_M_in_end;
	465	bool __testput = this->_M_out_cur
	466	&& this->_M_out_beg < this->_M_out_lim;
	467	// Sync the internal and external streams.
	468	// out
	469	if (__testput \|\| _M_last_overflowed)
	470	{
	471	// Part one: update the output sequence.
	472	this->sync();
	473	// Part two: output unshift sequence.
	474	_M_output_unshift();
	475	}
	476	//in
	477	else if (__testget && __way == ios_base::cur)
	478	__computed_off += this->_M_in_cur - _M_filepos;
	479
	480	// Return pos_type(off_type(-1)) in case of failure.
	481	__ret = _M_file.seekoff(__computed_off, __way, __sync, __mode);
	482	_M_set_indeterminate();
	483	}
	484	// NB: Need to do this in case _M_file in indeterminate
	485	// state, ie _M_file._offset == -1
	486	else
	487	{
	488	pos_type __tmp =
	489	_M_file.seekoff(__off, ios_base::cur,
	490	__sync, __mode);
	491	if (__tmp >= 0)
	492	{
	493	// Seek successful.
	494	__ret = __tmp;
	495	__ret +=
	496	std::max(this->_M_out_cur, this->_M_in_cur) - _M_filepos;
	497	}
	498	}
	499	}
	500	_M_last_overflowed = false;
	501	return __ret;
	502	}
	503
	504	template<typename _CharT, typename _Traits>
	505	typename basic_filebuf<_CharT, _Traits>::pos_type
	506	basic_filebuf<_CharT, _Traits>::
	507	seekpos(pos_type __pos, ios_base::openmode __mode)
	508	{
	509	#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
	510	// 171. Strange seekpos() semantics due to joint position
	511	return this->seekoff(off_type(__pos), ios_base::beg, __mode);
	512	#endif
	513	}
	514
	515	template<typename _CharT, typename _Traits>
	516	void
	517	basic_filebuf<_CharT, _Traits>::
	518	_M_output_unshift()
	519	{ }
	520
	521	template<typename _CharT, typename _Traits>
	522	void
	523	basic_filebuf<_CharT, _Traits>::
	524	imbue(const locale& __loc)
	525	{
	526	bool __testbeg = gptr() == eback() && pptr() == pbase();
	527
	528	if (__testbeg && this->_M_buf_locale != __loc)
	529	this->_M_buf_locale = __loc;
	530
	531	// NB this may require the reconversion of previously
	532	// converted chars. This in turn may cause the reconstruction
	533	// of the original file. YIKES!!
	534	// XXX The part in the above comment is not done.
	535	_M_last_overflowed = false;
	536	}
	537
	538	// Inhibit implicit instantiations for required instantiations,
	539	// which are defined via explicit instantiations elsewhere.
	540	// NB: This syntax is a GNU extension.
	541	#if _GLIBCPP_EXTERN_TEMPLATE
	542	extern template class basic_filebuf<char>;
	543	extern template class basic_ifstream<char>;
	544	extern template class basic_ofstream<char>;
	545	extern template class basic_fstream<char>;
	546
	547	#ifdef _GLIBCPP_USE_WCHAR_T
	548	extern template class basic_filebuf<wchar_t>;
	549	extern template class basic_ifstream<wchar_t>;
	550	extern template class basic_ofstream<wchar_t>;
	551	extern template class basic_fstream<wchar_t>;
	552	#endif
	553	#endif
	554	} // namespace std
	555
	556	#endif