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

   1 // __enc_traits layer for filebuf -*- C++ -*-
   2
   3 // Copyright (C) 2002 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 state type, all other bits
  36   // equivalent to the required char_traits instantiations.
  37   template<typename _CharT>
  38     struct enc_char_traits: public std::char_traits<_CharT>
  39     {
  40       typedef std::__enc_traits state_type;
  41     };
  42
  43   template<typename _CharT>
  44     class enc_filebuf
  45     : public std::basic_filebuf<_CharT, enc_char_traits<_CharT> >
  46     {
  47     public:
  48       typedef typename enc_char_traits<_CharT>::state_type state_type;
  49
  50       enc_filebuf(state_type& __state)
  51       : std::basic_filebuf<_CharT, enc_char_traits<_CharT> >()
  52       {
  53         // Set state type to something useful.
  54         // Something more than copyconstructible is needed here, so
  55         // require copyconstructible + assignment operator.
  56         __glibcxx_class_requires(state_type, _SGIAssignableConcept);
  57         _M_state_cur = __state;
  58         _M_state_cur._M_init();
  59       };
  60     };
  61 } // namespace __gnu_cxx