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 
get_valueboost::property_tree::id_translator29         boost::optional<T> get_value(const T &v) { return v; }
put_valueboost::property_tree::id_translator30         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
52