source: NonGTP/Boost/boost/mpl/advance.hpp @ 857

Revision 857, 2.1 KB checked in by igarcia, 19 years ago (diff)
RevLine 
[857]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// $Source: /cvsroot/boost/boost/boost/mpl/advance.hpp,v $
14// $Date: 2004/09/02 15:40:41 $
15// $Revision: 1.9 $
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
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