libstdc++-v3/include/ext/enc_filebuf.h

   1 // filebuf with __enc_traits state type -*- C++ -*-
   2
   3 // Copyright (C) 2002, 2003 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 2, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 #include <fstream>
  31 #include <locale>
  32
  33 namespace __gnu_cxx
  34 {
  35   // Custom traits type with __enc_traits for the state type, and the
  36   // associated fpos<__enc_traits> for the position type, all other
  37   // bits equivalent to the required char_traits instantiations.
  38   template<typename _CharT>
  39     struct enc_char_traits: public std::char_traits<_CharT>
  40     {
  41       typedef std::__enc_traits                 state_type;
  42       typedef typename std::fpos<state_type>    pos_type;
  43     };
  44
  45   template<typename _CharT>
  46     class enc_filebuf
  47     : public std::basic_filebuf<_CharT, enc_char_traits<_CharT> >
  48     {
  49     public:
  50       typedef enc_char_traits<_CharT>           traits_type;
  51       typedef typename traits_type::state_type  state_type;
  52       typedef typename traits_type::pos_type    pos_type;
  53
  54       enc_filebuf(state_type& __state)
  55       : std::basic_filebuf<_CharT, enc_char_traits<_CharT> >()
  56       {
  57         this->_M_state_beg = __state;
  58         this->_M_state_beg._M_init();
  59       }
  60
  61     private:
  62       // concept requirements:
  63       // Set state type to something useful.
  64       // Something more than copyconstructible is needed here, so
  65       // require default and copy constructible + assignment operator.
  66       __glibcxx_class_requires(state_type, _SGIAssignableConcept)
  67     };
  68 } // namespace __gnu_cxx