streambuf_iterator.h   [plain text]

// Streambuf iterators

// 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.

// XXX Should specialize copy, find algorithms for streambuf iterators.

/** @file streambuf_iterator.h
 *  This is an internal header file, included by other library headers.
 *  You should not attempt to use it directly.
 */

#ifndef _CPP_BITS_STREAMBUF_ITERATOR_H
#define _CPP_BITS_STREAMBUF_ITERATOR_H 1

#pragma GCC system_header

namespace std
{
  template<typename _CharT, typename _Traits>
    class ostreambuf_iterator
    : public iterator<output_iterator_tag, void, void, void, void>
    {
    public:
      // Types:
      typedef _CharT                           char_type;
      typedef _Traits                          traits_type;
      typedef basic_streambuf<_CharT, _Traits> streambuf_type;
      typedef basic_ostream<_CharT, _Traits>   ostream_type;

    private:
      streambuf_type* 	_M_sbuf;
      bool 		_M_failed;

    public:
      inline 
      ostreambuf_iterator(ostream_type& __s) throw ()
      : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { }
      
      ostreambuf_iterator(streambuf_type* __s) throw ()
      : _M_sbuf(__s), _M_failed(!_M_sbuf) { }

      ostreambuf_iterator& 
      operator=(_CharT __c);

      ostreambuf_iterator& 
      operator*() throw()
      { return *this; }

      ostreambuf_iterator& 
      operator++(int) throw()
      { return *this; }

      ostreambuf_iterator& 
      operator++() throw()
      { return *this; }

      bool 
      failed() const throw()
      { return _M_failed; }
    };

  template<typename _CharT, typename _Traits>
    inline ostreambuf_iterator<_CharT, _Traits>&
    ostreambuf_iterator<_CharT, _Traits>::operator=(_CharT __c)
    {
      if (!_M_failed && 
          _Traits::eq_int_type(_M_sbuf->sputc(__c),_Traits::eof()))
      _M_failed = true;
      return *this;
    }


  // 24.5.3 Template class istreambuf_iterator
  template<typename _CharT, typename _Traits>
    class istreambuf_iterator
    : public iterator<input_iterator_tag, _CharT, typename _Traits::off_type,
    		      _CharT*, _CharT&>
    {
    public:
      // Types:
      typedef _CharT                         		char_type;
      typedef _Traits                        		traits_type;
      typedef typename _Traits::int_type     		int_type;
      typedef basic_streambuf<_CharT, _Traits> 		streambuf_type;
      typedef basic_istream<_CharT, _Traits>         	istream_type;

    private:
      // 24.5.3 istreambuf_iterator 
      // p 1 
      // If the end of stream is reached (streambuf_type::sgetc()
      // returns traits_type::eof()), the iterator becomes equal to
      // the "end of stream" iterator value.
      // NB: This implementation assumes the "end of stream" value
      // is EOF, or -1.
      streambuf_type* 		_M_sbuf;  
      int_type 			_M_c;

    public:
      istreambuf_iterator() throw() 
      : _M_sbuf(NULL), _M_c(-2) { }
      
      istreambuf_iterator(istream_type& __s) throw()
      : _M_sbuf(__s.rdbuf()), _M_c(-2) { }

      istreambuf_iterator(streambuf_type* __s) throw()
      : _M_sbuf(__s), _M_c(-2) { }
       
      // NB: This should really have an int_type return
      // value, so "end of stream" postion can be checked without
      // hacking.
      char_type 
      operator*() const
      { 
	// The result of operator*() on an end of stream is undefined.
	char_type __ret;
	if (_M_sbuf && _M_c != static_cast<int_type>(-2))
	  __ret = _M_c;
	else if (_M_sbuf)
	  __ret = traits_type::to_char_type(_M_sbuf->sgetc()); 
	else
	  __ret = static_cast<char_type>(traits_type::eof());
	return __ret;
      }
	
      istreambuf_iterator& 
      operator++()
      { 
	if (_M_sbuf)
	  _M_sbuf->sbumpc();
	_M_c = -2;
	return *this; 
      }

      istreambuf_iterator
      operator++(int)
      {
	istreambuf_iterator __old = *this;
	if (_M_sbuf)
	  __old._M_c = _M_sbuf->sbumpc();
	_M_c = -2;
	return __old; 
      }

      bool 
      equal(const istreambuf_iterator& __b)
      { 
	int_type __eof = traits_type::eof();
	bool __thiseof = !_M_sbuf || _M_sbuf->sgetc() == __eof;
	bool __beof = !__b._M_sbuf || __b._M_sbuf->sgetc() == __eof;
	return (__thiseof && __beof || (!__thiseof && !__beof));
      }

#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
      // 110 istreambuf_iterator::equal not const
      // NB: there is also number 111 (NAD, Future) pending on this function.
      bool 
      equal(const istreambuf_iterator& __b) const
      {
	int_type __eof = traits_type::eof();
	bool __thiseof = !_M_sbuf || _M_sbuf->sgetc() == __eof;
	bool __beof = !__b._M_sbuf || __b._M_sbuf->sgetc() == __eof;
	return (__thiseof && __beof || (!__thiseof && !__beof));
      }
#endif
    };

  template<typename _CharT, typename _Traits>
    inline bool 
    operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
	       const istreambuf_iterator<_CharT, _Traits>& __b)
    { return __a.equal(__b); }

  template<typename _CharT, typename _Traits>
    inline bool 
    operator!=(const istreambuf_iterator<_CharT, _Traits>& __a,
	       const istreambuf_iterator<_CharT, _Traits>& __b)
    { return !__a.equal(__b); }
} // namespace std
#endif