ceph/src/boost/libs/property_tree/include/boost/property_tree/id_translator.hpp

   1 // ----------------------------------------------------------------------------
   2 // Copyright (C) 2009 Sebastian Redl
   3 //
   4 // Distributed under the Boost Software License, Version 1.0.
   5 // (See accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt)
   7 //
   8 // For more information, see www.boost.org
   9 // ----------------------------------------------------------------------------
  10
  11 #ifndef BOOST_PROPERTY_TREE_ID_TRANSLATOR_HPP_INCLUDED
  12 #define BOOST_PROPERTY_TREE_ID_TRANSLATOR_HPP_INCLUDED
  13
  14 #include <boost/property_tree/ptree_fwd.hpp>
  15
  16 #include <boost/optional.hpp>
  17 #include <string>
  18
  19 namespace boost { namespace property_tree
  20 {
  21
  22     /// Simple implementation of the Translator concept. It does no translation.
  23     template <typename T>
  24     struct id_translator
  25     {
  26         typedef T internal_type;
  27         typedef T external_type;
  28
  29         boost::optional<T> get_value(const T &v) { return v; }
  30         boost::optional<T> put_value(const T &v) { return v; }
  31     };
  32
  33     // This is the default translator whenever you get two equal types.
  34     template <typename T>
  35     struct translator_between<T, T>
  36     {
  37         typedef id_translator<T> type;
  38     };
  39
  40     // A more specific specialization for std::basic_string. Otherwise,
  41     // stream_translator's specialization wins.
  42     template <typename Ch, typename Traits, typename Alloc>
  43     struct translator_between< std::basic_string<Ch, Traits, Alloc>,
  44                                std::basic_string<Ch, Traits, Alloc> >
  45     {
  46         typedef id_translator< std::basic_string<Ch, Traits, Alloc> > type;
  47     };
  48
  49 }}
  50
  51 #endif