ceph/src/boost/libs/mpl/include/boost/mpl/advance.hpp

   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
  30 namespace boost { namespace mpl {
  31
  32 // default implementation for forward/bidirectional iterators
  33 template< typename Tag >
  34 struct 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
  52 template<
  53       typename BOOST_MPL_AUX_NA_PARAM(Iterator)
  54     , typename BOOST_MPL_AUX_NA_PARAM(N)
  55     >
  56 struct advance
  57     : advance_impl< typename tag<Iterator>::type >
  58         ::template apply<Iterator,N>
  59 {
  60 };
  61
  62 template<
  63       typename Iterator
  64     , BOOST_MPL_AUX_NTTP_DECL(long, N)
  65     >
  66 struct advance_c
  67     : advance_impl< typename tag<Iterator>::type >
  68         ::template apply<Iterator,long_<N> >
  69 {
  70 };
  71
  72 BOOST_MPL_AUX_NA_SPEC(2, advance)
  73
  74 }}
  75
  76 #endif // BOOST_MPL_ADVANCE_HPP_INCLUDED