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- /* Copyright 2006-2008 Joaquin M Lopez Munoz.
- * 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)
- *
- * See http://www.boost.org/libs/flyweight for library home page.
- */
- #ifndef BOOST_FLYWEIGHT_FACTORY_TAG_HPP
- #define BOOST_FLYWEIGHT_FACTORY_TAG_HPP
- #if defined(_MSC_VER)
- #pragma once
- #endif
- #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
- #include <boost/parameter/parameters.hpp>
- #include <boost/type_traits/is_base_and_derived.hpp>
- namespace boost{
- namespace flyweights{
- /* Three ways to indicate that a given class T is a factory specifier:
- * 1. Make it derived from factory_marker.
- * 2. Specialize is_factory to evaluate to boost::mpl::true_.
- * 3. Pass it as factory<T> when defining a flyweight type.
- */
- struct factory_marker{};
- template<typename T>
- struct is_factory:is_base_and_derived<factory_marker,T>
- {};
- template<typename T=parameter::void_>
- struct factory:parameter::template_keyword<factory<>,T>
- {};
- } /* namespace flyweights */
- } /* namespace boost */
- #endif
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