Imported existing code

libraries/include/boost/pending/ct_if.hpp

@@ -0,0 +1,43 @@
+// (C) Copyright Jeremy Siek 2000.
+// Distributed under 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)
+
+// This header replaces the implementation of ct_if that preceded the
+// introduction of Boost.MPL with a facade that defers to that reviewed and
+// accepted library.
+
+// Author: Ronald Garcia
+// Date: 20 October, 2006
+
+
+#ifndef BOOST_CT_IF_HPP
+#define BOOST_CT_IF_HPP
+
+
+// A stub implementation in terms of Boost.MPL
+
+#include <boost/mpl/if.hpp>
+#include <boost/mpl/not.hpp>
+#include <boost/mpl/and.hpp>
+// true_type and false_type are used by applications of ct_if
+#include <boost/type_traits/integral_constant.hpp> 
+
+namespace boost {
+
+  template <class A, class B>
+  struct ct_and : boost::mpl::and_<A,B> {};
+
+  template <class A>
+  struct ct_not : mpl::not_<A> {};
+
+  template <bool cond, class A, class B>
+  struct ct_if : mpl::if_c<cond,A,B> {};
+
+  template <class cond, class A, class B>
+  struct ct_if_t : mpl::if_<cond,A,B> {};
+
+} // namespace boost
+
+#endif // BOOST_CT_IF_HPP
+