fstream.tcc

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

// Copyright (C) 1997, 1998, 1999, 2000, 2001 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

namespace std
{
  template<typename _CharT, typename _Traits>
    void
    basic_filebuf<_CharT, _Traits>::
    _M_allocate_file()
    {
      if (!_M_file)
	{
	  _M_buf_unified = true; // Tie input to output for basic_filebuf.
	  try 
	    { _M_file = new __file_type(&_M_lock); }
	  catch(...) 
	    {
	      delete _M_file;
	      __throw_exception_again;
	    }
	}
    }

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

	  // Allocate internal buffer.
	  try { _M_buf = new char_type[_M_buf_size]; }
	  catch(...) 
	    {
	      delete [] _M_buf;
	      __throw_exception_again;
	    }
	  _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 [] _M_buf;
	  _M_buf = NULL;
	  _M_buf_allocated = false;
	  this->setg(NULL, NULL, NULL);
	  this->setp(NULL, NULL);
	}
    }

 template<typename _CharT, typename _Traits>
    void
    basic_filebuf<_CharT, _Traits>::
    _M_allocate_pback_buffer()
    {
      if (!_M_pback && _M_pback_size)
	{
	  // Allocate pback buffer.
	  try 
	    { _M_pback = new char_type[_M_pback_size]; }
	  catch(...) 
	    {
	      delete [] _M_pback;
	      __throw_exception_again;
	    }
	}
    }

  template<typename _CharT, typename _Traits>
    basic_filebuf<_CharT, _Traits>::
    basic_filebuf() 
    : __streambuf_type(), _M_file(NULL), _M_state_cur(__state_type()), 
    _M_state_beg(__state_type()), _M_buf_allocated(false), 
    _M_last_overflowed(false)
    { }

  template<typename _CharT, typename _Traits>
    basic_filebuf<_CharT, _Traits>::
    basic_filebuf(__c_file_type* __f, ios_base::openmode __mode, int_type __s)
    : __streambuf_type(),  _M_file(NULL), _M_state_cur(__state_type()), 
    _M_state_beg(__state_type()), _M_buf_allocated(false), 
    _M_last_overflowed(false)
    {
      _M_allocate_file();
      _M_file->sys_open(__f, __mode);
      if (this->is_open())
	{
	  _M_mode = __mode;
	  if (__s)
	    {
	      _M_buf_size_opt = __s;
	      _M_allocate_internal_buffer();
	      _M_set_indeterminate();
	    }
	  _M_allocate_pback_buffer();
	}
    }

  template<typename _CharT, typename _Traits>
    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_allocate_file();
	  _M_file->open(__s, __mode);
	  if (this->is_open())
	    {
	      _M_allocate_internal_buffer();
	      _M_allocate_pback_buffer();
	      _M_mode = __mode;
	      
	      // For time being, set both (in/out) sets  of pointers.
	      _M_set_indeterminate();
	      if (__mode & ios_base::ate
		  && this->seekoff(0, ios_base::end, __mode) < 0)
		this->close();
	      __ret = this;
	    }
	}
      return __ret;
    }

  template<typename _CharT, typename _Traits>
    basic_filebuf<_CharT, _Traits>::__filebuf_type* 
    basic_filebuf<_CharT, _Traits>::
    close()
    {
      __filebuf_type *__ret = NULL;
      if (this->is_open())
	{
	  bool __testput = _M_out_cur && _M_out_beg < _M_out_end;
	  if (__testput)
	    _M_really_overflow(traits_type::eof());

	  // NB: Do this here so that re-opened filebufs will be cool...
	  _M_pback_destroy();

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

	  _M_mode = ios_base::openmode(0);
	  _M_destroy_internal_buffer();

	  if (_M_pback)
	    {
	      delete [] _M_pback;
	      _M_pback = NULL;
	    }
	  __ret = this;
	}

      // Can actually allocate this file as part of an open and never
      // have it be opened.....
      if (_M_file)
	{
	  delete _M_file;
	  _M_file = NULL;
	}
      _M_last_overflowed = false;	
      return __ret;
    }

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

      if (__testin)
	{
	  bool __testeof = false;
	  if (_M_in_cur >= _M_in_end)
	    __testeof = this->underflow() == traits_type::eof();
	  if (!__testeof)
	    __ret = _M_in_end - _M_in_cur;
	}
      _M_last_overflowed = false;	
      return __ret;
    }

  template<typename _CharT, typename _Traits>
    basic_filebuf<_CharT, _Traits>::int_type 
    basic_filebuf<_CharT, _Traits>::
    underflow()
    {
      int_type __ret = traits_type::eof();
      bool __testin = _M_mode & ios_base::in;
      bool __testout = _M_mode & ios_base::out;

      // XXX Should re-enable codecvt bits disabled after 2.90.8.
      if (__testin)
	{
	  // Check for pback madness, and if so swich back to the
	  // normal buffers and jet outta here before expensive
	  // fileops happen...
	  if (_M_pback_init)
	    {
	      _M_pback_destroy();
	      if (_M_in_cur < _M_in_end)
		return traits_type::to_int_type(*_M_in_cur);
	    }

	  bool __testget = _M_in_cur && _M_in_beg < _M_in_cur;
	  bool __testinit = _M_is_indeterminate();
	  // Sync internal and external buffers.
	  // NB: __testget -> __testput as _M_buf_unified here.
	  if (__testget)
	    {
	      if (__testout)
		_M_really_overflow();
#if _GLIBCPP_AVOID_FSEEK
	      else if ((_M_in_cur - _M_in_beg) == 1)
		_M_file->sys_getc();
#endif
	      else 
		_M_file->seekoff(_M_in_cur - _M_in_beg, 
				 ios_base::cur, ios_base::in);
	    }

	  if (__testinit || __testget)
	    {
	      // Assume buffered case, need to refill internal buffers.
	      streamsize __size = _M_file->xsgetn(_M_in_beg, _M_buf_size);
	      if (0 < __size)
		{
		  _M_set_determinate(__size);
		  if (__testout)
		    _M_out_cur = _M_in_cur;
		  __ret = traits_type::to_int_type(*_M_in_cur);
#if _GLIBCPP_AVOID_FSEEK
		  if (__size == 1)
		    _M_file->sys_ungetc(*_M_in_cur);
		  else
		    {
#endif
		  streamoff __p = _M_file->seekoff(0 - __size, ios_base::cur, 
						   ios_base::in);
		  if (__p == -1)
		    {
		      // XXX Something is wrong, do error checking.
		    }
#if _GLIBCPP_AVOID_FSEEK
		    }
#endif
		}	   
	    }
	}
      _M_last_overflowed = false;	
      return __ret;
    }