ceph/src/boost/boost/fusion/view/single_view/detail/distance_impl.hpp

   1 /*=============================================================================
   2     Copyright (c) 2011 Eric Niebler
   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
   8 #if !defined(BOOST_FUSION_SINGLE_VIEW_DISTANCE_IMPL_JUL_07_2011_1348PM)
   9 #define BOOST_FUSION_SINGLE_VIEW_DISTANCE_IMPL_JUL_07_2011_1348PM
  10
  11 #include <boost/fusion/support/config.hpp>
  12 #include <boost/mpl/minus.hpp>
  13
  14 namespace boost { namespace fusion
  15 {
  16     struct single_view_iterator_tag;
  17
  18     namespace extension
  19     {
  20         template<typename Tag>
  21         struct distance_impl;
  22
  23         template<>
  24         struct distance_impl<single_view_iterator_tag>
  25         {
  26             template<typename First, typename Last>
  27             struct apply
  28               : mpl::minus<typename Last::position, typename First::position>
  29             {
  30                 typedef typename mpl::minus<typename Last::position,
  31                     typename First::position>::type type;
  32
  33                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  34                 static type
  35                 call(First const& /*first*/, Last const& /*last*/)
  36                 {
  37                     return type();
  38                 }
  39             };
  40         };
  41     }
  42
  43 }}
  44
  45 #endif