ceph/src/boost/libs/fusion/include/boost/fusion/iterator/distance.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2011 Joel de Guzman
   3
   4     Distributed under the Boost Software License, Version 1.0. (See accompanying
   5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 ==============================================================================*/
   7 #if !defined(FUSION_DISTANCE_09172005_0721)
   8 #define FUSION_DISTANCE_09172005_0721
   9
  10 #include <boost/fusion/support/config.hpp>
  11 #include <boost/fusion/iterator/detail/distance.hpp>
  12 #include <boost/fusion/support/category_of.hpp>
  13
  14 #include <boost/mpl/int.hpp>
  15 #include <boost/mpl/assert.hpp>
  16 #include <boost/type_traits/is_same.hpp>
  17
  18 #include <boost/fusion/support/tag_of.hpp>
  19
  20 namespace boost { namespace fusion
  21 {
  22     struct random_access_traversal_tag;
  23
  24     // Special tags:
  25     struct iterator_facade_tag; // iterator facade tag
  26     struct boost_array_iterator_tag; // boost::array iterator tag
  27     struct mpl_iterator_tag; // mpl sequence iterator tag
  28     struct std_pair_iterator_tag; // std::pair iterator tag
  29
  30     namespace extension
  31     {
  32         template <typename Tag>
  33         struct distance_impl
  34         {
  35             // default implementation
  36             template <typename First, typename Last>
  37             struct apply : distance_detail::linear_distance<First, Last>
  38             {};
  39         };
  40
  41         template <>
  42         struct distance_impl<iterator_facade_tag>
  43         {
  44             template <typename First, typename Last>
  45             struct apply : First::template distance<First, Last> {};
  46         };
  47
  48         template <>
  49         struct distance_impl<boost_array_iterator_tag>;
  50
  51         template <>
  52         struct distance_impl<mpl_iterator_tag>;
  53
  54         template <>
  55         struct distance_impl<std_pair_iterator_tag>;
  56     }
  57
  58     namespace result_of
  59     {
  60         template <typename First, typename Last>
  61         struct distance
  62           : extension::distance_impl<typename detail::tag_of<First>::type>::
  63                 template apply<First, Last>
  64         {
  65             typedef typename extension::distance_impl<typename detail::tag_of<First>::type>::
  66             template apply<First, Last>::type distance_application;
  67             BOOST_STATIC_CONSTANT(int, value = distance_application::value);
  68         };
  69     }
  70
  71     template <typename First, typename Last>
  72     BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  73     inline typename result_of::distance<First, Last>::type
  74     distance(First const& a, Last const& b)
  75     {
  76         return result_of::distance<First, Last>::call(a,b);
  77     }
  78 }}
  79
  80 #endif