1 //
2 //=======================================================================
3 // Author: Philipp Moeller
4 //
5 // Copyright 2012, Philipp Moeller
6 //
7 // Distributed under the Boost Software License, Version 1.0. (See
8 // accompanying file LICENSE_1_0.txt or copy at
9 // http://www.boost.org/LICENSE_1_0.txt)
10 //=======================================================================
11 //
12
13 #ifndef BOOST_PROPERTY_MAP_TRANSFORM_VALUE_PROPERTY_MAP_HPP
14 #define BOOST_PROPERTY_MAP_TRANSFORM_VALUE_PROPERTY_MAP_HPP
15
16 #include <boost/config.hpp>
17 #include <boost/property_map/property_map.hpp>
18 #include <boost/type_traits.hpp>
19 #include <boost/utility/result_of.hpp>
20 #include <boost/mpl/and.hpp>
21 #include <boost/mpl/not.hpp>
22 #include <utility>
23
24 namespace boost {
25
26 template<typename Func, typename PM, typename Ret = typename boost::result_of<const Func(typename property_traits<PM>::reference)>::type>
27 class transform_value_property_map: public put_get_helper<Ret, transform_value_property_map<Func, PM, Ret> > {
28 public:
29 typedef typename property_traits<PM>::key_type key_type;
30 typedef Ret reference;
31 typedef typename boost::remove_cv<typename boost::remove_reference<Ret>::type>::type value_type;
32
33 typedef typename boost::mpl::if_<
34 boost::mpl::and_<
35 boost::is_reference<Ret>,
36 boost::mpl::not_<boost::is_const<Ret> >
37 >,
38 boost::lvalue_property_map_tag,
39 boost::readable_property_map_tag>::type
40 category;
41
transform_value_property_map(Func f,PM pm)42 transform_value_property_map(Func f, PM pm) : f(f), pm(pm) {}
43
operator [](const key_type & k) const44 reference operator[](const key_type& k) const {
45 return f(get(pm, k));
46 }
47
48 private:
49 Func f;
50 PM pm;
51 };
52
53 template<typename PM, typename Func>
54 transform_value_property_map<Func, PM>
make_transform_value_property_map(const Func & f,const PM & pm)55 make_transform_value_property_map(const Func& f, const PM& pm) {
56 return transform_value_property_map<Func, PM>(f, pm);
57 }
58
59 template<typename Ret, typename PM, typename Func>
60 transform_value_property_map<Func, PM, Ret>
make_transform_value_property_map(const Func & f,const PM & pm)61 make_transform_value_property_map(const Func& f, const PM& pm) {
62 return transform_value_property_map<Func, PM, Ret>(f, pm);
63 }
64
65 } // boost
66
67 #endif /* BOOST_PROPERTY_MAP_TRANSFORM_VALUE_PROPERTY_MAP_HPP */
68