ceph/src/boost/boost/geometry/util/combine_if.hpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2014-2015 Samuel Debionne, Grenoble, France.
   4
   5 // This file was modified by Oracle on 2015-2020.
   6 // Modifications copyright (c) 2015-2020, Oracle and/or its affiliates.
   7
   8 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
   9 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
  10
  11 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
  12 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
  13
  14 // Use, modification and distribution is subject to the Boost Software License,
  15 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  16 // http://www.boost.org/LICENSE_1_0.txt)
  17
  18 #ifndef BOOST_GEOMETRY_UTIL_COMBINE_IF_HPP
  19 #define BOOST_GEOMETRY_UTIL_COMBINE_IF_HPP
  20
  21 #include <boost/config/pragma_message.hpp>
  22 #if !defined(BOOST_ALLOW_DEPRECATED_HEADERS)
  23 BOOST_PRAGMA_MESSAGE("This header is deprecated.")
  24 #endif
  25
  26 #include <boost/mpl/bind.hpp>
  27 #include <boost/mpl/fold.hpp>
  28 #include <boost/mpl/if.hpp>
  29 #include <boost/mpl/insert.hpp>
  30 #include <boost/mpl/pair.hpp>
  31 #include <boost/mpl/placeholders.hpp>
  32 #include <boost/mpl/set.hpp>
  33
  34 namespace boost { namespace geometry
  35 {
  36
  37 namespace util
  38 {
  39
  40
  41 /*!
  42     \brief Meta-function to generate all the combination of pairs of types
  43         from a given sequence Sequence except those that does not satisfy the
  44         predicate Pred
  45     \ingroup utility
  46     \par Example
  47     \code
  48         typedef boost::mpl::vector<boost::mpl::int_<0>, boost::mpl::int_<1> > types;
  49         typedef combine_if<types, types, always<true_> >::type combinations;
  50         typedef boost::mpl::vector<
  51             pair<boost::mpl::int_<1>, boost::mpl::int_<1> >,
  52             pair<boost::mpl::int_<1>, boost::mpl::int_<0> >,
  53             pair<boost::mpl::int_<0>, boost::mpl::int_<1> >,
  54             pair<boost::mpl::int_<0>, boost::mpl::int_<0> >
  55         > result_types;
  56
  57         BOOST_MPL_ASSERT(( boost::mpl::equal<combinations, result_types> ));
  58     \endcode
  59 */
  60 template <typename Sequence1, typename Sequence2, typename Pred>
  61 struct combine_if
  62 {
  63     struct combine
  64     {
  65         template <typename Result, typename T>
  66         struct apply
  67         {
  68             typedef typename boost::mpl::fold<Sequence2, Result,
  69                 boost::mpl::if_
  70                 <
  71                     boost::mpl::bind
  72                         <
  73                             typename boost::mpl::lambda<Pred>::type,
  74                             T,
  75                             boost::mpl::_2
  76                         >,
  77                     boost::mpl::insert
  78                         <
  79                             boost::mpl::_1, boost::mpl::pair<T, boost::mpl::_2>
  80                         >,
  81                     boost::mpl::_1
  82                 >
  83             >::type type;
  84         };
  85     };
  86
  87     typedef typename boost::mpl::fold
  88         <
  89             Sequence1, boost::mpl::set0<>, combine
  90         >::type type;
  91 };
  92
  93
  94 } // namespace util
  95
  96 }} // namespace boost::geometry
  97
  98 #endif // BOOST_GEOMETRY_UTIL_COMBINE_IF_HPP