/*============================================================================= | |
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 |