diff options
Diffstat (limited to 'boost/flyweight/factory_tag.hpp')
-rw-r--r-- | boost/flyweight/factory_tag.hpp | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/boost/flyweight/factory_tag.hpp b/boost/flyweight/factory_tag.hpp new file mode 100644 index 0000000000..ddb747304e --- /dev/null +++ b/boost/flyweight/factory_tag.hpp @@ -0,0 +1,44 @@ +/* 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)&&(_MSC_VER>=1200) +#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 |