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Diffstat (limited to 'boost/type_erasure/binding.hpp')
| -rw-r--r-- | boost/type_erasure/binding.hpp | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/boost/type_erasure/binding.hpp b/boost/type_erasure/binding.hpp new file mode 100644 index 0000000000..a5023a59eb --- /dev/null +++ b/boost/type_erasure/binding.hpp @@ -0,0 +1,250 @@ +// Boost.TypeErasure library +// +// Copyright 2011 Steven Watanabe +// +// 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) +// +// $Id$ + +#ifndef BOOST_TYPE_ERASURE_BINDING_HPP_INCLUDED +#define BOOST_TYPE_ERASURE_BINDING_HPP_INCLUDED + +#include <boost/config.hpp> +#include <boost/shared_ptr.hpp> +#include <boost/make_shared.hpp> +#include <boost/utility/enable_if.hpp> +#include <boost/mpl/transform.hpp> +#include <boost/mpl/find_if.hpp> +#include <boost/mpl/and.hpp> +#include <boost/mpl/not.hpp> +#include <boost/mpl/end.hpp> +#include <boost/mpl/bool.hpp> +#include <boost/mpl/pair.hpp> +#include <boost/type_traits/is_same.hpp> +#include <boost/type_erasure/static_binding.hpp> +#include <boost/type_erasure/is_subconcept.hpp> +#include <boost/type_erasure/detail/adapt_to_vtable.hpp> +#include <boost/type_erasure/detail/null.hpp> +#include <boost/type_erasure/detail/rebind_placeholders.hpp> +#include <boost/type_erasure/detail/vtable.hpp> +#include <boost/type_erasure/detail/normalize.hpp> +#include <boost/type_erasure/detail/instantiate.hpp> +#include <boost/type_erasure/detail/check_map.hpp> + +namespace boost { +namespace type_erasure { + +namespace detail { + +template<class Source, class Dest, class Map> +struct can_optimize_conversion : ::boost::mpl::and_< + ::boost::is_same<Source, Dest>, + ::boost::is_same< + typename ::boost::mpl::find_if< + Map, + ::boost::mpl::not_< + ::boost::is_same< + ::boost::mpl::first< ::boost::mpl::_1>, + ::boost::mpl::second< ::boost::mpl::_1> + > + > + >::type, + typename ::boost::mpl::end<Map>::type + > + >::type +{}; + +} + +/** + * Stores the binding of a @c Concept to a set of actual types. + * @c Concept is interpreted in the same way as with @ref any. + */ +template<class Concept> +class binding +{ + typedef typename ::boost::type_erasure::detail::normalize_concept< + Concept>::type normalized; + typedef typename ::boost::mpl::transform<normalized, + ::boost::type_erasure::detail::maybe_adapt_to_vtable< ::boost::mpl::_1> + >::type actual_concept; + typedef typename ::boost::type_erasure::detail::make_vtable< + actual_concept>::type table_type; + typedef typename ::boost::type_erasure::detail::get_placeholder_normalization_map< + Concept + >::type placeholder_subs; +public: + + /** + * \pre @ref relaxed must be in @c Concept. + * + * \throws Nothing. + */ + binding() { BOOST_MPL_ASSERT((::boost::type_erasure::is_relaxed<Concept>)); } + + /** + * \pre @c Map must be an MPL map with an entry for each placeholder + * referred to by @c Concept. + * + * \throws Nothing. + */ + template<class Map> + explicit binding(const Map&) + : impl(( + BOOST_TYPE_ERASURE_INSTANTIATE(Concept, Map), + static_binding<Map>() + )) + {} + + /** + * \pre @c Map must be an MPL map with an entry for each placeholder + * referred to by @c Concept. + * + * \throws Nothing. + */ + template<class Map> + binding(const static_binding<Map>&) + : impl(( + BOOST_TYPE_ERASURE_INSTANTIATE(Concept, Map), + static_binding<Map>() + )) + {} + + /** + * Converts from another set of bindings. + * + * \pre Map must be an MPL map with an entry for each placeholder + * referred to by @c Concept. The mapped type should be the + * corresponding placeholder in Concept2. + * + * \throws std::bad_alloc + */ + template<class Concept2, class Map> + binding(const binding<Concept2>& other, const Map& +#ifndef BOOST_TYPE_ERASURE_DOXYGEN + , typename ::boost::enable_if< + ::boost::mpl::and_< + ::boost::type_erasure::detail::check_map<Concept, Map>, + ::boost::type_erasure::is_subconcept<Concept, Concept2, Map> + > + >::type* = 0 +#endif + ) + : impl( + other, + static_binding<Map>(), + ::boost::type_erasure::detail::can_optimize_conversion<Concept2, Concept, Map>() + ) + {} + + /** + * Converts from another set of bindings. + * + * \pre Map must be an MPL map with an entry for each placeholder + * referred to by @c Concept. The mapped type should be the + * corresponding placeholder in Concept2. + * + * \throws std::bad_alloc + */ + template<class Concept2, class Map> + binding(const binding<Concept2>& other, const static_binding<Map>& +#ifndef BOOST_TYPE_ERASURE_DOXYGEN + , typename ::boost::enable_if< + ::boost::mpl::and_< + ::boost::type_erasure::detail::check_map<Concept, Map>, + ::boost::type_erasure::is_subconcept<Concept, Concept2, Map> + > + >::type* = 0 +#endif + ) + : impl( + other, + static_binding<Map>(), + ::boost::type_erasure::detail::can_optimize_conversion<Concept2, Concept, Map>() + ) + {} + + /** + * \return true iff the sets of types that the placeholders + * bind to are the same for both arguments. + * + * \throws Nothing. + */ + friend bool operator==(const binding& lhs, const binding& rhs) + { return *lhs.impl.table == *rhs.impl.table; } + + /** + * \return true iff the arguments do not map to identical + * sets of types. + * + * \throws Nothing. + */ + friend bool operator!=(const binding& lhs, const binding& rhs) + { return !(lhs == rhs); } + + /** INTERNAL ONLY */ + template<class T> + typename T::type find() const { return impl.table->lookup((T*)0); } +private: + template<class C2> + friend class binding; + /** INTERNAL ONLY */ + struct impl_type + { + impl_type() { + table = &::boost::type_erasure::detail::make_vtable_init< + typename ::boost::mpl::transform< + actual_concept, + ::boost::type_erasure::detail::get_null_vtable_entry< + ::boost::mpl::_1 + > + >::type, + table_type + >::type::value; + } + template<class Map> + impl_type(const static_binding<Map>&) + { + table = &::boost::type_erasure::detail::make_vtable_init< + typename ::boost::mpl::transform< + actual_concept, + ::boost::type_erasure::detail::rebind_placeholders< + ::boost::mpl::_1, + typename ::boost::type_erasure::detail::add_deductions< + Map, + placeholder_subs + >::type + > + >::type, + table_type + >::type::value; + } + template<class Concept2, class Map> + impl_type(const binding<Concept2>& other, const static_binding<Map>&, boost::mpl::false_) + : manager(new table_type) + { + manager->template convert_from< + typename ::boost::type_erasure::detail::convert_deductions< + Map, + placeholder_subs, + typename binding<Concept2>::placeholder_subs + >::type + >(*other.impl.table); + table = manager.get(); + } + template<class Concept2, class Map> + impl_type(const binding<Concept2>& other, const static_binding<Map>&, boost::mpl::true_) + : table(other.impl.table), + manager(other.impl.manager) + {} + const table_type* table; + ::boost::shared_ptr<table_type> manager; + } impl; +}; + +} +} + +#endif |