streambuf_iterator.h

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00001 // Streambuf iterators
00002 
00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002
00004 // Free Software Foundation, Inc.
00005 //
00006 // This file is part of the GNU ISO C++ Library.  This library is free
00007 // software; you can redistribute it and/or modify it under the
00008 // terms of the GNU General Public License as published by the
00009 // Free Software Foundation; either version 2, or (at your option)
00010 // any later version.
00011 
00012 // This library is distributed in the hope that it will be useful,
00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015 // GNU General Public License for more details.
00016 
00017 // You should have received a copy of the GNU General Public License along
00018 // with this library; see the file COPYING.  If not, write to the Free
00019 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
00020 // USA.
00021 
00022 // As a special exception, you may use this file as part of a free software
00023 // library without restriction.  Specifically, if other files instantiate
00024 // templates or use macros or inline functions from this file, or you compile
00025 // this file and link it with other files to produce an executable, this
00026 // file does not by itself cause the resulting executable to be covered by
00027 // the GNU General Public License.  This exception does not however
00028 // invalidate any other reasons why the executable file might be covered by
00029 // the GNU General Public License.
00030 
00031 // XXX Should specialize copy, find algorithms for streambuf iterators.
00032 
00038 #ifndef _CPP_BITS_STREAMBUF_ITERATOR_H
00039 #define _CPP_BITS_STREAMBUF_ITERATOR_H 1
00040 
00041 #pragma GCC system_header
00042 
00043 namespace std
00044 {
00045   // 24.5.3 Template class istreambuf_iterator
00046   template<typename _CharT, typename _Traits>
00047     class istreambuf_iterator
00048     : public iterator<input_iterator_tag, _CharT, typename _Traits::off_type,
00049                   _CharT*, _CharT&>
00050     {
00051     public:
00052       // Types:
00053       typedef _CharT                                char_type;
00054       typedef _Traits                               traits_type;
00055       typedef typename _Traits::int_type            int_type;
00056       typedef basic_streambuf<_CharT, _Traits>      streambuf_type;
00057       typedef basic_istream<_CharT, _Traits>            istream_type;
00058 
00059     private:
00060       // 24.5.3 istreambuf_iterator 
00061       // p 1 
00062       // If the end of stream is reached (streambuf_type::sgetc()
00063       // returns traits_type::eof()), the iterator becomes equal to
00064       // the "end of stream" iterator value.
00065       // NB: This implementation assumes the "end of stream" value
00066       // is EOF, or -1.
00067       mutable streambuf_type*   _M_sbuf;  
00068       int_type          _M_c;
00069 
00070     public:
00071       istreambuf_iterator() throw() 
00072       : _M_sbuf(0), _M_c(traits_type::eof()) { }
00073       
00074       istreambuf_iterator(istream_type& __s) throw()
00075       : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { }
00076 
00077       istreambuf_iterator(streambuf_type* __s) throw()
00078       : _M_sbuf(__s), _M_c(traits_type::eof()) { }
00079        
00080       // NB: The result of operator*() on an end of stream is undefined.
00081       char_type 
00082       operator*() const
00083       { return traits_type::to_char_type(_M_get()); }
00084     
00085       istreambuf_iterator& 
00086       operator++()
00087       { 
00088     const int_type __eof = traits_type::eof();
00089     if (_M_sbuf && traits_type::eq_int_type(_M_sbuf->sbumpc(), __eof))
00090       _M_sbuf = 0;
00091     else
00092       _M_c = __eof;
00093     return *this; 
00094       }
00095 
00096       istreambuf_iterator
00097       operator++(int)
00098       {
00099     const int_type __eof = traits_type::eof();
00100     istreambuf_iterator __old = *this;
00101     if (_M_sbuf
00102         && traits_type::eq_int_type((__old._M_c = _M_sbuf->sbumpc()), 
00103                     __eof))
00104       _M_sbuf = 0;
00105     else
00106       _M_c = __eof;
00107     return __old; 
00108       }
00109 
00110 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
00111       // 110 istreambuf_iterator::equal not const
00112       // NB: there is also number 111 (NAD, Future) pending on this function.
00113       bool 
00114       equal(const istreambuf_iterator& __b) const
00115       {
00116     const int_type __eof = traits_type::eof();
00117     bool __thiseof = traits_type::eq_int_type(_M_get(), __eof);
00118     bool __beof = traits_type::eq_int_type(__b._M_get(), __eof);
00119     return (__thiseof && __beof || (!__thiseof && !__beof));
00120       }
00121 #endif
00122 
00123     private:
00124       int_type 
00125       _M_get() const
00126       { 
00127     const int_type __eof = traits_type::eof();
00128     int_type __ret = __eof;
00129     if (_M_sbuf)
00130       { 
00131         if (!traits_type::eq_int_type(_M_c, __eof))
00132           __ret = _M_c;
00133         else 
00134           if (traits_type::eq_int_type((__ret = _M_sbuf->sgetc()), __eof))
00135         _M_sbuf = 0;
00136       }
00137     return __ret;
00138       }
00139     };
00140 
00141   template<typename _CharT, typename _Traits>
00142     inline bool 
00143     operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
00144            const istreambuf_iterator<_CharT, _Traits>& __b)
00145     { return __a.equal(__b); }
00146 
00147   template<typename _CharT, typename _Traits>
00148     inline bool 
00149     operator!=(const istreambuf_iterator<_CharT, _Traits>& __a,
00150            const istreambuf_iterator<_CharT, _Traits>& __b)
00151     { return !__a.equal(__b); }
00152 
00153   template<typename _CharT, typename _Traits>
00154     class ostreambuf_iterator
00155     : public iterator<output_iterator_tag, void, void, void, void>
00156     {
00157     public:
00158       // Types:
00159       typedef _CharT                           char_type;
00160       typedef _Traits                          traits_type;
00161       typedef basic_streambuf<_CharT, _Traits> streambuf_type;
00162       typedef basic_ostream<_CharT, _Traits>   ostream_type;
00163 
00164     private:
00165       streambuf_type*   _M_sbuf;
00166       bool      _M_failed;
00167 
00168     public:
00169       inline 
00170       ostreambuf_iterator(ostream_type& __s) throw ()
00171       : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { }
00172       
00173       ostreambuf_iterator(streambuf_type* __s) throw ()
00174       : _M_sbuf(__s), _M_failed(!_M_sbuf) { }
00175 
00176       ostreambuf_iterator& 
00177       operator=(_CharT __c);
00178 
00179       ostreambuf_iterator& 
00180       operator*() throw()
00181       { return *this; }
00182 
00183       ostreambuf_iterator& 
00184       operator++(int) throw()
00185       { return *this; }
00186 
00187       ostreambuf_iterator& 
00188       operator++() throw()
00189       { return *this; }
00190 
00191       bool 
00192       failed() const throw()
00193       { return _M_failed; }
00194     };
00195 
00196   template<typename _CharT, typename _Traits>
00197     inline ostreambuf_iterator<_CharT, _Traits>&
00198     ostreambuf_iterator<_CharT, _Traits>::operator=(_CharT __c)
00199     {
00200       if (!_M_failed && 
00201           _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof()))
00202     _M_failed = true;
00203       return *this;
00204     }
00205 } // namespace std
00206 #endif

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