| /*============================================================================= |
| Copyright (c) 2001-2006 Joel de Guzman |
| |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| ==============================================================================*/ |
| #if !defined(FUSION_DISTANCE_09172005_0730) |
| #define FUSION_DISTANCE_09172005_0730 |
| |
| #include <boost/mpl/int.hpp> |
| #include <boost/mpl/if.hpp> |
| #include <boost/mpl/eval_if.hpp> |
| #include <boost/mpl/next.hpp> |
| #include <boost/mpl/identity.hpp> |
| #include <boost/fusion/iterator/next.hpp> |
| #include <boost/fusion/iterator/equal_to.hpp> |
| |
| namespace boost { namespace fusion { namespace distance_detail |
| { |
| // Default distance implementation, linear |
| // search for the Last iterator. |
| |
| template <typename First, typename Last> |
| struct linear_distance; |
| |
| template <typename First, typename Last> |
| struct next_distance |
| { |
| typedef typename |
| mpl::next< |
| typename linear_distance< |
| typename result_of::next<First>::type |
| , Last |
| >::type |
| >::type |
| type; |
| }; |
| |
| template <typename First, typename Last> |
| struct linear_distance |
| : mpl::eval_if< |
| result_of::equal_to<First, Last> |
| , mpl::identity<mpl::int_<0> > |
| , next_distance<First, Last> |
| >::type |
| { |
| typedef typename |
| mpl::eval_if< |
| result_of::equal_to<First, Last> |
| , mpl::identity<mpl::int_<0> > |
| , next_distance<First, Last> |
| >::type |
| type; |
| |
| static type |
| call(First const&, Last const&) |
| { |
| return type(); |
| } |
| }; |
| |
| }}} |
| |
| #endif |