1
2#ifndef BOOST_MPL_ADVANCE_HPP_INCLUDED
3#define BOOST_MPL_ADVANCE_HPP_INCLUDED
4
5// Copyright Aleksey Gurtovoy 2000-2004
6//
7// Distributed under the Boost Software License, Version 1.0.
8// (See accompanying file LICENSE_1_0.txt or copy at
9// http://www.boost.org/LICENSE_1_0.txt)
10//
11// See http://www.boost.org/libs/mpl for documentation.
12
13// $Id$
14// $Date$
15// $Revision$
16
17#include <boost/mpl/advance_fwd.hpp>
18#include <boost/mpl/less.hpp>
19#include <boost/mpl/negate.hpp>
20#include <boost/mpl/long.hpp>
21#include <boost/mpl/if.hpp>
22#include <boost/mpl/tag.hpp>
23#include <boost/mpl/apply_wrap.hpp>
24#include <boost/mpl/aux_/advance_forward.hpp>
25#include <boost/mpl/aux_/advance_backward.hpp>
26#include <boost/mpl/aux_/value_wknd.hpp>
27#include <boost/mpl/aux_/na_spec.hpp>
28#include <boost/mpl/aux_/nttp_decl.hpp>
29
30namespace boost { namespace mpl {
31
32// default implementation for forward/bidirectional iterators
33template< typename Tag >
34struct advance_impl
35{
36 template< typename Iterator, typename N > struct apply
37 {
38 typedef typename less< N,long_<0> >::type backward_;
39 typedef typename if_< backward_, negate<N>, N >::type offset_;
40
41 typedef typename if_<
42 backward_
43 , aux::advance_backward< BOOST_MPL_AUX_VALUE_WKND(offset_)::value >
44 , aux::advance_forward< BOOST_MPL_AUX_VALUE_WKND(offset_)::value >
45 >::type f_;
46
47 typedef typename apply_wrap1<f_,Iterator>::type type;
48 };
49};
50
51
52template<
53 typename BOOST_MPL_AUX_NA_PARAM(Iterator)
54 , typename BOOST_MPL_AUX_NA_PARAM(N)
55 >
56struct advance
57 : advance_impl< typename tag<Iterator>::type >
58 ::template apply<Iterator,N>
59{
60};
61
62template<
63 typename Iterator
64 , BOOST_MPL_AUX_NTTP_DECL(long, N)
65 >
66struct advance_c
67 : advance_impl< typename tag<Iterator>::type >
68 ::template apply<Iterator,long_<N> >
69{
70};
71
72BOOST_MPL_AUX_NA_SPEC(2, advance)
73
74}}
75
76#endif // BOOST_MPL_ADVANCE_HPP_INCLUDED
77

source code of include/boost/mpl/advance.hpp