Chris@102: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@102: 
Chris@102: // Copyright (c) 2014-2015 Samuel Debionne, Grenoble, France.
Chris@102: 
Chris@102: // This file was modified by Oracle on 2015.
Chris@102: // Modifications copyright (c) 2015, Oracle and/or its affiliates.
Chris@102: 
Chris@102: // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
Chris@102: 
Chris@102: // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
Chris@102: // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
Chris@102: 
Chris@102: // Use, modification and distribution is subject to the Boost Software License,
Chris@102: // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@102: // http://www.boost.org/LICENSE_1_0.txt)
Chris@102: 
Chris@102: #ifndef BOOST_GEOMETRY_UTIL_COMBINE_IF_HPP
Chris@102: #define BOOST_GEOMETRY_UTIL_COMBINE_IF_HPP
Chris@102: 
Chris@102: #include <boost/mpl/fold.hpp>
Chris@102: #include <boost/mpl/if.hpp>
Chris@102: #include <boost/mpl/bind.hpp>
Chris@102: #include <boost/mpl/set.hpp>
Chris@102: #include <boost/mpl/insert.hpp>
Chris@102: #include <boost/mpl/placeholders.hpp>
Chris@102: 
Chris@102: #include <boost/type_traits.hpp>
Chris@102: 
Chris@102: 
Chris@102: namespace boost { namespace geometry
Chris@102: {
Chris@102: 
Chris@102: namespace util
Chris@102: {
Chris@102: 
Chris@102: 
Chris@102: /*!
Chris@102:     \brief Meta-function to generate all the combination of pairs of types
Chris@102:         from a given sequence Sequence except those that does not satisfy the
Chris@102:         predicate Pred
Chris@102:     \ingroup utility
Chris@102:     \par Example
Chris@102:     \code
Chris@102:         typedef boost::mpl::vector<boost::mpl::int_<0>, boost::mpl::int_<1> > types;
Chris@102:         typedef combine_if<types, types, always<true_> >::type combinations;
Chris@102:         typedef boost::mpl::vector<
Chris@102:             pair<boost::mpl::int_<1>, boost::mpl::int_<1> >,
Chris@102:             pair<boost::mpl::int_<1>, boost::mpl::int_<0> >,
Chris@102:             pair<boost::mpl::int_<0>, boost::mpl::int_<1> >,
Chris@102:             pair<boost::mpl::int_<0>, boost::mpl::int_<0> >        
Chris@102:         > result_types;
Chris@102:         
Chris@102:         BOOST_MPL_ASSERT(( boost::mpl::equal<combinations, result_types> ));
Chris@102:     \endcode
Chris@102: */
Chris@102: template <typename Sequence1, typename Sequence2, typename Pred>
Chris@102: struct combine_if
Chris@102: {
Chris@102:     struct combine
Chris@102:     {
Chris@102:         template <typename Result, typename T>
Chris@102:         struct apply
Chris@102:         {
Chris@102:             typedef typename boost::mpl::fold<Sequence2, Result,
Chris@102:                 boost::mpl::if_
Chris@102:                 <
Chris@102:                     boost::mpl::bind
Chris@102:                         <
Chris@102:                             typename boost::mpl::lambda<Pred>::type,
Chris@102:                             T,
Chris@102:                             boost::mpl::_2
Chris@102:                         >,
Chris@102:                     boost::mpl::insert
Chris@102:                         <
Chris@102:                             boost::mpl::_1, boost::mpl::pair<T, boost::mpl::_2>
Chris@102:                         >,
Chris@102:                     boost::mpl::_1
Chris@102:                 >
Chris@102:             >::type type;
Chris@102:         };
Chris@102:     };
Chris@102: 
Chris@102:     typedef typename boost::mpl::fold
Chris@102:         <
Chris@102:             Sequence1, boost::mpl::set0<>, combine
Chris@102:         >::type type;
Chris@102: };
Chris@102: 
Chris@102: 
Chris@102: } // namespace util
Chris@102: 
Chris@102: }} // namespace boost::geometry
Chris@102: 
Chris@102: #endif // BOOST_GEOMETRY_UTIL_COMBINE_IF_HPP