williamr@2: 
williamr@2: #ifndef BOOST_MPL_ADVANCE_HPP_INCLUDED
williamr@2: #define BOOST_MPL_ADVANCE_HPP_INCLUDED
williamr@2: 
williamr@2: // Copyright Aleksey Gurtovoy 2000-2004
williamr@2: //
williamr@2: // Distributed under the Boost Software License, Version 1.0. 
williamr@2: // (See accompanying file LICENSE_1_0.txt or copy at 
williamr@2: // http://www.boost.org/LICENSE_1_0.txt)
williamr@2: //
williamr@2: // See http://www.boost.org/libs/mpl for documentation.
williamr@2: 
williamr@2: // $Source: /cvsroot/boost/boost/boost/mpl/advance.hpp,v $
williamr@2: // $Date: 2004/09/02 15:40:41 $
williamr@2: // $Revision: 1.9 $
williamr@2: 
williamr@2: #include <boost/mpl/advance_fwd.hpp>
williamr@2: #include <boost/mpl/less.hpp>
williamr@2: #include <boost/mpl/negate.hpp>
williamr@2: #include <boost/mpl/long.hpp>
williamr@2: #include <boost/mpl/if.hpp>
williamr@2: #include <boost/mpl/tag.hpp>
williamr@2: #include <boost/mpl/apply_wrap.hpp>
williamr@2: #include <boost/mpl/aux_/advance_forward.hpp>
williamr@2: #include <boost/mpl/aux_/advance_backward.hpp>
williamr@2: #include <boost/mpl/aux_/value_wknd.hpp>
williamr@2: #include <boost/mpl/aux_/na_spec.hpp>
williamr@2: #include <boost/mpl/aux_/nttp_decl.hpp>
williamr@2: 
williamr@2: namespace boost { namespace mpl {
williamr@2: 
williamr@2: // default implementation for forward/bidirectional iterators
williamr@2: template< typename Tag >
williamr@2: struct advance_impl
williamr@2: {
williamr@2:     template< typename Iterator, typename N > struct apply
williamr@2:     {
williamr@2:         typedef typename less< N,long_<0> >::type backward_;
williamr@2:         typedef typename if_< backward_, negate<N>, N >::type offset_;
williamr@2: 
williamr@2:         typedef typename if_<
williamr@2:               backward_
williamr@2:             , aux::advance_backward< BOOST_MPL_AUX_VALUE_WKND(offset_)::value >
williamr@2:             , aux::advance_forward< BOOST_MPL_AUX_VALUE_WKND(offset_)::value >
williamr@2:             >::type f_;
williamr@2: 
williamr@2:         typedef typename apply_wrap1<f_,Iterator>::type type;
williamr@2:     };
williamr@2: };
williamr@2: 
williamr@2: 
williamr@2: template<
williamr@2:       typename BOOST_MPL_AUX_NA_PARAM(Iterator)
williamr@2:     , typename BOOST_MPL_AUX_NA_PARAM(N)
williamr@2:     >
williamr@2: struct advance
williamr@2:     : advance_impl< typename tag<Iterator>::type >
williamr@2:         ::template apply<Iterator,N>
williamr@2: {
williamr@2: };
williamr@2: 
williamr@2: template<
williamr@2:       typename Iterator
williamr@2:     , BOOST_MPL_AUX_NTTP_DECL(long, N)
williamr@2:     >
williamr@2: struct advance_c
williamr@2:     : advance_impl< typename tag<Iterator>::type >
williamr@2:         ::template apply<Iterator,long_<N> >
williamr@2: {
williamr@2: };
williamr@2: 
williamr@2: BOOST_MPL_AUX_NA_SPEC(2, advance)
williamr@2: 
williamr@2: }}
williamr@2: 
williamr@2: #endif // BOOST_MPL_ADVANCE_HPP_INCLUDED