ceph/src/boost/libs/msm/include/boost/msm/mpl_graph/mpl_utils.hpp

   1 // Copyright 2008-2010 Gordon Woodhull
   2 // Distributed under the Boost Software License, Version 1.0.
   3 // (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   4
   5 #ifndef BOOST_MSM_MPL_GRAPH_MPL_UTILS_HPP_INCLUDED
   6 #define BOOST_MSM_MPL_GRAPH_MPL_UTILS_HPP_INCLUDED
   7
   8 #include <boost/mpl/fold.hpp>
   9 #include <boost/mpl/map.hpp>
  10 #include <boost/mpl/set.hpp>
  11 #include <boost/mpl/insert.hpp>
  12 #include <boost/mpl/if.hpp>
  13 #include <boost/mpl/has_key.hpp>
  14 #include <boost/mpl/at.hpp>
  15 #include <boost/mpl/and.hpp>
  16
  17 namespace boost {
  18 namespace msm {
  19 namespace mpl_graph {
  20 namespace mpl_utils {
  21
  22 // This is a grab bag of little metafunctions I expect already
  23 // exist under some name I haven't looked for
  24
  25 // I figure there are probably better ways to do all of these things,
  26 // but for now I'll just write some utilities to isolate my ignorance
  27
  28 template<typename Seq>
  29 struct as_map :
  30     mpl::fold<Seq,
  31               mpl::map<>,
  32               mpl::insert<mpl::_1, mpl::_2> >
  33 {};
  34 template<typename Seq>
  35 struct as_set :
  36     mpl::fold<Seq,
  37               mpl::set<>,
  38               mpl::insert<mpl::_1, mpl::_2> >
  39 {};
  40
  41 template<typename AssocSeq, typename Key, typename Default>
  42 struct at_or_default :
  43     mpl::if_<typename mpl::has_key<AssocSeq, Key>::type,
  44              typename mpl::at<AssocSeq, Key>::type,
  45              Default>
  46 {};
  47
  48 template<typename Seq1, typename Seq2>
  49 struct set_equal :
  50     mpl::fold<Seq2,
  51               mpl::true_,
  52               mpl::and_<mpl::_1,
  53                         mpl::has_key<typename as_set<Seq1>::type,
  54                                      mpl::_2 > > >
  55 {};
  56
  57 }
  58 }
  59 }
  60 }
  61
  62 #endif // BOOST_MSM_MPL_GRAPH_MPL_UTILS_HPP_INCLUDED