Chris@16: 
Chris@16: #ifndef BOOST_MPL_ADVANCE_HPP_INCLUDED
Chris@16: #define BOOST_MPL_ADVANCE_HPP_INCLUDED
Chris@16: 
Chris@16: // Copyright Aleksey Gurtovoy 2000-2004
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. 
Chris@16: // (See accompanying file LICENSE_1_0.txt or copy at 
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/mpl for documentation.
Chris@16: 
Chris@101: // $Id$
Chris@101: // $Date$
Chris@101: // $Revision$
Chris@16: 
Chris@16: #include <boost/mpl/advance_fwd.hpp>
Chris@16: #include <boost/mpl/less.hpp>
Chris@16: #include <boost/mpl/negate.hpp>
Chris@16: #include <boost/mpl/long.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/mpl/tag.hpp>
Chris@16: #include <boost/mpl/apply_wrap.hpp>
Chris@16: #include <boost/mpl/aux_/advance_forward.hpp>
Chris@16: #include <boost/mpl/aux_/advance_backward.hpp>
Chris@16: #include <boost/mpl/aux_/value_wknd.hpp>
Chris@16: #include <boost/mpl/aux_/na_spec.hpp>
Chris@16: #include <boost/mpl/aux_/nttp_decl.hpp>
Chris@16: 
Chris@16: namespace boost { namespace mpl {
Chris@16: 
Chris@16: // default implementation for forward/bidirectional iterators
Chris@16: template< typename Tag >
Chris@16: struct advance_impl
Chris@16: {
Chris@16:     template< typename Iterator, typename N > struct apply
Chris@16:     {
Chris@16:         typedef typename less< N,long_<0> >::type backward_;
Chris@16:         typedef typename if_< backward_, negate<N>, N >::type offset_;
Chris@16: 
Chris@16:         typedef typename if_<
Chris@16:               backward_
Chris@16:             , aux::advance_backward< BOOST_MPL_AUX_VALUE_WKND(offset_)::value >
Chris@16:             , aux::advance_forward< BOOST_MPL_AUX_VALUE_WKND(offset_)::value >
Chris@16:             >::type f_;
Chris@16: 
Chris@16:         typedef typename apply_wrap1<f_,Iterator>::type type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template<
Chris@16:       typename BOOST_MPL_AUX_NA_PARAM(Iterator)
Chris@16:     , typename BOOST_MPL_AUX_NA_PARAM(N)
Chris@16:     >
Chris@16: struct advance
Chris@16:     : advance_impl< typename tag<Iterator>::type >
Chris@16:         ::template apply<Iterator,N>
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template<
Chris@16:       typename Iterator
Chris@16:     , BOOST_MPL_AUX_NTTP_DECL(long, N)
Chris@16:     >
Chris@16: struct advance_c
Chris@16:     : advance_impl< typename tag<Iterator>::type >
Chris@16:         ::template apply<Iterator,long_<N> >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: BOOST_MPL_AUX_NA_SPEC(2, advance)
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif // BOOST_MPL_ADVANCE_HPP_INCLUDED