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

   1 // filebuf with __enc_traits state type -*- C++ -*-
   2
   3 // Copyright (C) 2002, 2003, 2004 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 /** @file ext/enc_filebuf.h
  31  *  This file is a GNU extension to the Standard C++ Library.
  32  */
  33
  34 #include <fstream>
  35 #include <locale>
  36
  37 namespace __gnu_cxx
  38 {
  39   // Custom traits type with __enc_traits for the state type, and the
  40   // associated fpos<__enc_traits> for the position type, all other
  41   // bits equivalent to the required char_traits instantiations.
  42   /// @brief  class enc_char_traits.
  43   template<typename _CharT>
  44     struct enc_char_traits: public std::char_traits<_CharT>
  45     {
  46       typedef std::__enc_traits                 state_type;
  47       typedef typename std::fpos<state_type>    pos_type;
  48     };
  49
  50   /// @brief  class enc_filebuf.
  51   template<typename _CharT>
  52     class enc_filebuf
  53     : public std::basic_filebuf<_CharT, enc_char_traits<_CharT> >
  54     {
  55     public:
  56       typedef enc_char_traits<_CharT>           traits_type;
  57       typedef typename traits_type::state_type  state_type;
  58       typedef typename traits_type::pos_type    pos_type;
  59
  60       enc_filebuf(state_type& __state)
  61       : std::basic_filebuf<_CharT, enc_char_traits<_CharT> >()
  62       {
  63         this->_M_state_beg = __state;
  64         this->_M_state_beg._M_init();
  65       }
  66
  67     private:
  68       // concept requirements:
  69       // Set state type to something useful.
  70       // Something more than copyconstructible is needed here, so
  71       // require default and copy constructible + assignment operator.
  72       __glibcxx_class_requires(state_type, _SGIAssignableConcept)
  73     };
  74 } // namespace __gnu_cxx