fstream

symbian上STL模板库的实现

      // [documentation is inherited]
      virtual streamsize
      xsputn(const char_type* __s, streamsize __n);

      // Flushes output buffer, then writes unshift sequence.
      /**
       *  @if maint
       *  @doctodo
       *  @endif
      */
      bool
      _M_terminate_output();

      /**
       *  @if maint 
       *  This function sets the pointers of the internal buffer, both get
       *  and put areas. Typically:
       *
       *   __off == egptr() - eback() upon underflow/uflow ('read' mode);
       *   __off == 0 upon overflow ('write' mode);
       *   __off == -1 upon open, setbuf, seekoff/pos ('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.
       *  @endif
      */
      void
      _M_set_buffer(streamsize __off)
      {
 	const bool __testin = this->_M_mode & ios_base::in;
 	const bool __testout = this->_M_mode & ios_base::out;
	
	if (__testin && __off > 0)
	  this->setg(this->_M_buf, this->_M_buf, this->_M_buf + __off);
	else
	  this->setg(this->_M_buf, this->_M_buf, this->_M_buf);

	if (__testout && __off == 0 && this->_M_buf_size > 1 )
	  this->setp(this->_M_buf, this->_M_buf + this->_M_buf_size - 1);
	else
	  this->setp(NULL, NULL);
      }
    };

  // [27.8.1.5] Template class basic_ifstream
  /**
   *  @brief  Controlling input for files.
   *
   *  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<typename _CharT, typename _Traits>
    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<char_type, traits_type> 	__filebuf_type;
      typedef basic_istream<char_type, traits_type>	__istream_type;

    private:
      /**
       *  @if maint
       *  @doctodo
       *  @endif
      */
      __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);
      }

      /**
       *  @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(); }

      /**
       *  @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);
      }

      /**
       *  @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.
   *
   *  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<typename _CharT, typename _Traits>
    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<char_type, traits_type> 	__filebuf_type;
      typedef basic_ostream<char_type, traits_type>	__ostream_type;

    private:
      /**
       *  @if maint
       *  @doctodo
       *  @endif
      */
      __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|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);
      }

      /**
       *  @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(); }

      /**
       *  @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);
      }

      /**
       *  @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 intput and output for files.
   *
   *  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<typename _CharT, typename _Traits>
    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<char_type, traits_type> 	__filebuf_type;
      typedef basic_ios<char_type, traits_type>		__ios_type;
      typedef basic_iostream<char_type, traits_type>	__iostream_type;

    private:
      /**
       *  @if maint
       *  @doctodo
       *  @endif
      */
      __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(NULL), _M_filebuf()
      {
	this->init(&_M_filebuf);
	this->open(__s, __mode);
      }

      /**
       *  @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(); }

      /**
       *  @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);
      }

      /**
       *  @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);
      }
    };
} // namespace std

#ifndef _GLIBCXX_EXPORT_TEMPLATE
# include <bits/fstream.tcc>
#endif

#endif /* _GLIBCXX_FSTREAM */