boost_ext/boost/bimap/relation/support/data_extractor.hpp

   1 // Boost.Bimap
   2 //
   3 // Copyright (c) 2006-2007 Matias Capeletto
   4 //
   5 // Distributed under the Boost Software License, Version 1.0.
   6 // (See accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt)
   8
   9 /// \file relation/support/data_extractor.hpp
  10 /// \brief Data extraction functor.
  11
  12 #ifndef BOOST_BIMAP_RELATION_SUPPORT_DATA_EXTRACTOR_HPP
  13 #define BOOST_BIMAP_RELATION_SUPPORT_DATA_EXTRACTOR_HPP
  14
  15 #if defined(_MSC_VER) && (_MSC_VER>=1200)
  16 #pragma once
  17 #endif
  18
  19 #include <boost/config.hpp>
  20
  21 #include <boost/bimap/relation/detail/metadata_access_builder.hpp>
  22
  23 /** \struct boost::bimaps::relation::support::data_extractor
  24
  25 \brief Data extraction functor.
  26
  27 \ingroup relation_group
  28                                                                     **/
  29
  30 #ifndef BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES
  31
  32 namespace boost {
  33 namespace bimaps {
  34 namespace relation {
  35 namespace support {
  36
  37 template< class Tag, class Relation >
  38 struct data_extractor_implementation;
  39
  40 template< class Relation >
  41 struct data_extractor_implementation< member_at::left, Relation > :
  42     public std::unary_function<Relation,BOOST_DEDUCED_TYPENAME Relation::left_value_type>
  43 {
  44     BOOST_DEDUCED_TYPENAME Relation::left_value_type const &
  45         operator()(Relation const & rel) const
  46     {
  47         return rel.left;
  48     }
  49
  50     BOOST_DEDUCED_TYPENAME Relation::left_value_type &
  51         operator()(Relation       & rel) const
  52     {
  53         return rel.left;
  54     }
  55 };
  56
  57 template< class Relation >
  58 struct data_extractor_implementation< member_at::right, Relation > :
  59     public std::unary_function<Relation,BOOST_DEDUCED_TYPENAME Relation::right_value_type>
  60 {
  61     BOOST_DEDUCED_TYPENAME Relation::right_value_type const &
  62         operator()(Relation const & rel) const
  63     {
  64         return rel.right;
  65     }
  66
  67     BOOST_DEDUCED_TYPENAME Relation::right_value_type &
  68         operator()(Relation       & rel) const
  69     {
  70         return rel.right;
  71     }
  72 };
  73
  74 template< class Tag, class Relation >
  75 struct data_extractor
  76 {
  77     typedef data_extractor_implementation
  78     <
  79         BOOST_DEDUCED_TYPENAME member_with_tag<Tag,Relation>::type,
  80         Relation
  81
  82     > type;
  83 };
  84
  85 template< class Relation >
  86 struct both_keys_extractor
  87 {
  88     typedef BOOST_DEDUCED_TYPENAME Relation::storage_base result_type;
  89
  90      const result_type & operator()(const Relation & rel) const
  91     {
  92         return rel;
  93     }
  94
  95     result_type & operator()( Relation & rel) const
  96     {
  97         return rel;
  98     }
  99 };
 100
 101 } // namespace support
 102 } // namespace relation
 103 } // namespace bimaps
 104 } // namespace boost
 105
 106 #endif // BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES
 107
 108 #endif // BOOST_BIMAP_RELATION_SUPPORT_DATA_EXTRACTOR_HPP
 109