std_fstream.h

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

// Copyright (C) 1997-1999 Cygnus Solutions
//
// 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_FSTREAM
#define _CPP_FSTREAM	1

#include <bits/std_istream.h>
#include <bits/std_ostream.h>
#include <bits/basic_file.h>
#include <bits/std_locale.h>	// For codecvt

namespace std {

  template<typename _CharT, typename _Traits>
    class basic_filebuf : public basic_streambuf<_CharT, _Traits>
    {
      // Types:
      typedef _CharT                     	       	  char_type;
      typedef typename _Traits::int_type 		  int_type;
      typedef typename _Traits::pos_type 		  pos_type;
      typedef typename _Traits::off_type 		  off_type;
      typedef _Traits                    		  traits_type;

      // Non-standard Types:
      typedef basic_streambuf<_CharT, _Traits> 		  __streambuf_type;
      typedef basic_filebuf<_CharT, _Traits>		  __filebuf_type;
      typedef __basic_file				  __file_type;
      typedef typename _Traits::state_type                __state_type;
      typedef codecvt<_CharT, char, __state_type>         __codecvt_type;
      typedef codecvt<_CharT, char, __state_type>::result __res_type;
      
      // Data Members:
      __file_type* 		_M_file;
      bool			_M_last_overflowed;  // XXX Needed?
      __state_type		_M_state_cur;// Current state type for codecvt.
      __state_type 		_M_state_beg; 	
      const __codecvt_type*	_M_fcvt;       // Cached value from use_facet.

    public:
      // Constructors/destructor:
      basic_filebuf();

      // Non-standard ctor:
      basic_filebuf(int __fd, const char* __name = "unknown", 
		    ios_base::openmode __mode = ios_base::in | ios_base::out);

      virtual 
      ~basic_filebuf() 
      { 
	this->close();
	_M_fcvt = NULL;
	delete _M_file;
	_M_file = NULL;
	_M_last_overflowed = false;
      }

      // Members:
      bool 
      is_open() const { return _M_file->is_open(); }
    
      __filebuf_type* 
      open(const char* __s, ios_base::openmode __mode);
    
      __filebuf_type* 
      close();

    protected:

      // Common initialization code for both ctors goes here.
      void
      _M_init_filebuf(void);

      // Overridden virtual functions:
      virtual streamsize 
      showmanyc();
   
      // Stroustrup, 1998, p. 628 
      // underflow() and uflow() functions are called to get the next
      // charater 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());

      // NB: For what the standard expects of the overflow function,
      // see _M_really_overflow(), below. Because basic_streambuf's
      // sputc/sputn call overflow directly, and the complications of
      // this implementation's setting of the initial pointers all
      // equal to _M_buf when initializing, it seems essential to have
      // this in actuality be a helper function that checks for the
      // eccentricities of this implementation, and then call
      // overflow() if indeed the buffer is full.
      virtual int_type 
      overflow(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.
      int_type 
      _M_really_overflow(int_type __c = _Traits::eof());
    
      virtual __streambuf_type* 
      setbuf(char_type* __s, streamsize __n)
      {
	if (!this->is_open() && __s == 0 && __n == 0)
	  _M_buf_size = 0;
	_M_last_overflowed = false;	
	return this; 
      }
    
      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)
      {
	pos_type __retval =  this->seekoff(__pos, ios_base::beg, __mode); 
	_M_last_overflowed = false;	
	return __retval;
      }

      virtual int 
      sync()
      {
	// Don't do anything about input sequences.
	bool __testput = _M_out_cur && _M_out_beg < _M_out_cur;
	if (__testput)
	  {
	    // Iff _M_mode is ios_base::out only, then need to set out
	    // pointers to the end of the current put sequence before
	    // we call _M_really_overflow, or else the stream will not be
	    // flushed. Back up, so overflow doesn't append extra characters.
	    this->_M_really_overflow();
	  }
	_M_file->sync();
	_M_last_overflowed = false;	
	return 0;
      }
      
      virtual void 
      imbue(const locale& __loc);

      void
      _M_output_unshift();
    };

  typedef basic_filebuf<char> filebuf;
  typedef basic_filebuf<wchar_t> wfilebuf;

  // 27.8.1.5  Template class basic_ifstream
  template<typename _CharT, typename _Traits>
    class basic_ifstream : public basic_istream<_CharT, _Traits>
    {
      // Types:
      typedef _CharT 				char_type;
      typedef typename _Traits::int_type 	int_type;
      typedef typename _Traits::pos_type 	pos_type;
      typedef typename _Traits::off_type 	off_type;
      typedef _Traits 				traits_type;

      // Non-standard types:
      typedef basic_filebuf<_CharT, _Traits> 	__filebuf_type;
      typedef basic_istream<_CharT, _Traits>	__istream_type;
    
    public:
      // Constructors/Destructors:
      basic_ifstream()
      : __istream_type(new __filebuf_type())
      { }

      explicit 
      basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in)
      : __istream_type(new __filebuf_type())
      { this->open(__s, __mode); }
    
      ~basic_ifstream()
      { 
	delete _M_streambuf; 
	_M_streambuf = NULL;
      }

      // Members:
      __filebuf_type* 
      rdbuf() const 
      { return static_cast<__filebuf_type*>(_M_streambuf); }

      bool 
      is_open() { return rdbuf()->is_open(); }

      void 
      open(const char* __s, ios_base::openmode __mode = ios_base::in)
      { 
	if (!rdbuf()->open(__s, __mode))
	  this->setstate(ios_base::failbit); 
      }

      void 
      close()
      { 
	if (!rdbuf()->close())
	  this->setstate(ios_base::failbit);	
      }
    };
  
  // 27.8.1.8  Template class basic_ofstream
  template<typename _CharT, typename _Traits>
    class basic_ofstream : public basic_ostream<_CharT,_Traits>
    {
       // Types:
      typedef _CharT 				char_type;
      typedef typename _Traits::int_type 	int_type;
      typedef typename _Traits::pos_type 	pos_type;
      typedef typename _Traits::off_type 	off_type;
      typedef _Traits 				traits_type;

      // Non-standard types:
      typedef basic_filebuf<_CharT, _Traits> 	__filebuf_type;
      typedef basic_ostream<_CharT, _Traits>	__ostream_type;
     
    public:
      // Constructors:
      basic_ofstream()
      : __ostream_type(new __filebuf_type())
      { }
      
      explicit 
      basic_ofstream(const char* __s, 
		     ios_base::openmode __mode = ios_base::out|ios_base::trunc)
      : __ostream_type(new __filebuf_type())
      { this->open(__s, __mode); }

      ~basic_ofstream()
      { 
	delete _M_streambuf; 
	_M_streambuf = NULL;
      }

      // Members:
      __filebuf_type* 
      rdbuf() const
      { return static_cast<__filebuf_type*>(_M_streambuf); }
 
      bool 
      is_open() { return rdbuf()->is_open(); }

      void 
      open(const char* __s, 
	   ios_base::openmode __mode = ios_base::out | ios_base::trunc)
      { 
	if (!rdbuf()->open(__s, __mode))
	  this->setstate (ios_base::failbit); 
      }

      void 
      close()
      { 
	if (!rdbuf()->close())
	  setstate (ios_base::failbit); 
      }
    };

  typedef basic_ofstream<char> ofstream;
  typedef basic_ofstream<wchar_t> wofstream;
  

  // 27.8.1.11  Template class basic_fstream
  template<typename _CharT, typename _Traits>
    class basic_fstream : public basic_iostream<_CharT, _Traits>
    {
       // Types:
      typedef _CharT 				char_type;
      typedef typename _Traits::int_type 	int_type;
      typedef typename _Traits::pos_type 	pos_type;
      typedef typename _Traits::off_type 	off_type;
      typedef _Traits 				traits_type;

      // Non-standard types:
      typedef basic_filebuf<_CharT, _Traits> 	__filebuf_type;
      typedef basic_ios<_CharT, _Traits>	__ios_type;
      typedef basic_iostream<_CharT, _Traits>	__iostream_type;

    public:
      // Constructors/destructor:
      basic_fstream()
      : __iostream_type(new __filebuf_type())
      { }

      explicit 
      basic_fstream(const char* __s,
		    ios_base::openmode __mode = ios_base::in | ios_base::out)
      : __iostream_type(new __filebuf_type())
      { this->open(__s, __mode); }

      ~basic_fstream()
      { 
	delete _M_streambuf; 
	_M_streambuf = NULL;
      }
    
      // Members:
      __filebuf_type* 
      rdbuf() const 
      { return static_cast<__filebuf_type*>(_M_streambuf); }

      bool 
      is_open() { return rdbuf()->is_open(); }

      void 
      open(const char* __s, 
	   ios_base::openmode __mode = ios_base::in | ios_base::out)
      { 
	if (!rdbuf()->open(__s, __mode))
	  setstate (ios_base::failbit); 
      }

      void 
      close()
      { 
	if (!rdbuf()->close())
	  setstate (ios_base::failbit); 
      }
    };

  typedef basic_fstream<char> fstream;
  typedef basic_fstream<wchar_t> wfstream;

} // namespace std


#ifdef _GLIBCPP_NO_TEMPLATE_EXPORT
# define export
# include <bits/fstream.tcc>
#endif

#endif	/* _CPP_FSTREAM */