1 files changed, 78 insertions, 0 deletions
diff --git a/boost/geometry/util/combine_if.hpp b/boost/geometry/util/combine_if.hpp
new file mode 100644
index 0000000000..6d8d932a1c
--- /dev/null
+++ b/boost/geometry/util/combine_if.hpp
@@ -0,0 +1,78 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+
+// Copyright (c) 2014 Samuel Debionne, Grenoble, France.
+
+// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
+// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_GEOMETRY_UTIL_COMBINE_IF_HPP
+#define BOOST_GEOMETRY_UTIL_COMBINE_IF_HPP
+
+#include <boost/mpl/fold.hpp>
+#include <boost/mpl/if.hpp>
+#include <boost/mpl/bind.hpp>
+#include <boost/mpl/set.hpp>
+#include <boost/mpl/insert.hpp>
+#include <boost/mpl/placeholders.hpp>
+
+#include <boost/type_traits.hpp>
+
+
+namespace boost { namespace geometry
+{
+
+namespace util
+{
+
+
+/*!
+    \brief Meta-function to generate all the combination of pairs of types
+        from a given sequence Sequence except those that does not satisfy the
+        predicate Pred
+    \ingroup utility
+    \par Example
+    \code
+        typedef mpl::vector<mpl::int_<0>, mpl::int_<1> > types;
+        typedef combine_if<types, types, always<true_> >::type combinations;
+        typedef mpl::vector<
+            pair<mpl::int_<1>, mpl::int_<1> >,
+            pair<mpl::int_<1>, mpl::int_<0> >,
+            pair<mpl::int_<0>, mpl::int_<1> >,
+            pair<mpl::int_<0>, mpl::int_<0> >        
+        > result_types;
+        
+        BOOST_MPL_ASSERT(( mpl::equal<combinations, result_types> ));
+    \endcode
+*/
+template <typename Sequence1, typename Sequence2, typename Pred>
+struct combine_if
+{
+    struct combine
+    {
+        template <typename Result, typename T>
+        struct apply
+        {
+            typedef typename mpl::fold<Sequence2, Result,
+                mpl::if_
+                <
+                    mpl::bind<typename mpl::lambda<Pred>::type, T, mpl::_2>,
+                    mpl::insert<mpl::_1, mpl::pair<T, mpl::_2> >,
+                    mpl::_1
+                >
+            >::type type;
+        };
+    };
+
+    typedef typename mpl::fold<Sequence1, mpl::set0<>, combine>::type type;
+};
+
+
+} // namespace util
+
+}} // namespace boost::geometry
+
+#endif // BOOST_GEOMETRY_UTIL_COMBINE_IF_HPP