ceph/src/boost/libs/property_map/include/boost/property_map/transform_value_property_map.hpp

   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
  42   transform_value_property_map(Func f, PM pm) : f(f), pm(pm) {}
  43
  44   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>
  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>
  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 */