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_IMPL_09172005_0751)
8 #define FUSION_DISTANCE_IMPL_09172005_0751
9 
10 #include <boost/fusion/support/config.hpp>
11 #include <boost/mpl/minus.hpp>
12 
13 namespace boost { namespace fusion
14 {
15     struct vector_iterator_tag;
16 
17     namespace extension
18     {
19         template <typename Tag>
20         struct distance_impl;
21 
22         template <>
23         struct distance_impl<vector_iterator_tag>
24         {
25             template <typename First, typename Last>
26             struct apply : mpl::minus<typename Last::index, typename First::index>
27             {
28                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
29                 static typename mpl::minus<
30                     typename Last::index, typename First::index>::type
callboost::fusion::extension::distance_impl::apply31                 call(First const&, Last const&)
32                 {
33                     typedef typename mpl::minus<
34                         typename Last::index, typename First::index>::type
35                     result;
36                     return result();
37                 }
38             };
39         };
40     }
41 }}
42 
43 #endif
44