boost/type_erasure/detail/vtable.hpp
// 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)
//
// $Id$
#if !defined(BOOST_PP_IS_ITERATING)
#ifndef BOOST_TYPE_ERASURE_DETAIL_VTABLE_HPP_INCLUDED
#define BOOST_TYPE_ERASURE_DETAIL_VTABLE_HPP_INCLUDED
#include <boost/config.hpp>
#include <boost/mpl/at.hpp>
#include <boost/mpl/size.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/expr_if.hpp>
#include <boost/preprocessor/iteration/iterate.hpp>
#include <boost/preprocessor/repetition/enum.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/repetition/enum_trailing.hpp>
#include <boost/preprocessor/repetition/enum_trailing_params.hpp>
#include <boost/preprocessor/repetition/repeat.hpp>
#include <boost/type_erasure/detail/rebind_placeholders.hpp>
#include <boost/type_erasure/config.hpp>
namespace boost {
namespace type_erasure {
namespace detail {
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_CONSTEXPR) && !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)
template<class... T>
struct stored_arg_pack;
template<class It, class End, class... T>
struct make_arg_pack_impl
{
typedef typename make_arg_pack_impl<
typename ::boost::mpl::next<It>::type,
End,
T...,
typename ::boost::mpl::deref<It>::type
>::type type;
};
template<class End, class... T>
struct make_arg_pack_impl<End, End, T...>
{
typedef stored_arg_pack<T...> type;
};
template<class Seq>
struct make_arg_pack
{
typedef typename make_arg_pack_impl<
typename ::boost::mpl::begin<Seq>::type,
typename ::boost::mpl::end<Seq>::type
>::type type;
};
template<class Args>
struct make_vtable_impl;
template<class Seq>
struct make_vtable
{
typedef typename ::boost::type_erasure::detail::make_vtable_impl<
typename ::boost::type_erasure::detail::make_arg_pack<Seq>::type
>::type type;
};
template<class Table, class Args>
struct make_vtable_init_impl;
template<class Seq, class Table>
struct make_vtable_init
{
typedef typename make_vtable_init_impl<
Table,
typename ::boost::type_erasure::detail::make_arg_pack<Seq>::type
>::type type;
};
template<class T>
struct vtable_entry
{
typename T::type value;
vtable_entry() = default;
constexpr vtable_entry(typename T::type arg) : value(arg) {}
};
template<class... T>
struct compare_vtable;
template<>
struct compare_vtable<> {
template<class S>
static bool apply(const S& /*s1*/, const S& /*s2*/)
{
return true;
}
};
template<class T0, class... T>
struct compare_vtable<T0, T...> {
template<class S>
static bool apply(const S& s1, const S& s2)
{
return static_cast<const vtable_entry<T0>&>(s1).value ==
static_cast<const vtable_entry<T0>&>(s2).value &&
compare_vtable<T...>::apply(s1, s2);
}
};
template<class... T>
struct vtable_storage : vtable_entry<T>...
{
vtable_storage() = default;
constexpr vtable_storage(typename T::type... arg)
: vtable_entry<T>(arg)... {}
template<class Bindings, class Src>
void convert_from(const Src& src)
{
*this = vtable_storage(
src.lookup(
(typename ::boost::type_erasure::detail::rebind_placeholders<
T, Bindings
>::type*)0)...);
}
bool operator==(const vtable_storage& other) const
{ return compare_vtable<T...>::apply(*this, other); }
template<class U>
typename U::type lookup(U*) const
{
return static_cast<const vtable_entry<U>*>(this)->value;
}
};
// Provide this specialization manually.
// gcc 4.7.2 fails to instantiate the primary template.
template<>
struct vtable_storage<>
{
vtable_storage() = default;
template<class Bindings, class Src>
void convert_from(const Src& /*src*/) {}
bool operator==(const vtable_storage& /*other*/) const
{ return true; }
};
template<class... T>
struct make_vtable_impl<stored_arg_pack<T...> >
{
typedef vtable_storage<T...> type;
};
template<class Table, class... T>
struct vtable_init
{
static constexpr Table value = Table(T::value...);
};
template<class Table, class... T>
constexpr Table vtable_init<Table, T...>::value;
template<class Table, class... T>
struct make_vtable_init_impl<Table, stored_arg_pack<T...> >
{
typedef vtable_init<Table, T...> type;
};
#else
template<int N>
struct make_vtable_impl;
template<class Seq>
struct make_vtable
{
typedef typename make_vtable_impl<
(::boost::mpl::size<Seq>::value)>::template apply<Seq>::type type;
};
template<int N>
struct make_vtable_init_impl;
template<class Seq, class Table>
struct make_vtable_init
{
typedef typename make_vtable_init_impl<
(::boost::mpl::size<Seq>::value)>::template apply<Seq, Table>::type type;
};
#define BOOST_PP_FILENAME_1 <boost/type_erasure/detail/vtable.hpp>
#define BOOST_PP_ITERATION_LIMITS (0, BOOST_TYPE_ERASURE_MAX_FUNCTIONS)
#include BOOST_PP_ITERATE()
#endif
}
}
}
#endif
#else
#define N BOOST_PP_ITERATION()
#define BOOST_TYPE_ERASURE_VTABLE_ENTRY(z, n, data) \
typename BOOST_PP_CAT(T, n)::type BOOST_PP_CAT(t, n); \
typename BOOST_PP_CAT(T, n)::type lookup(BOOST_PP_CAT(T, n)*) const \
{ \
return BOOST_PP_CAT(t, n); \
}
#define BOOST_TYPE_ERASURE_VTABLE_COMPARE(z, n, data) \
&& BOOST_PP_CAT(t, n) == other.BOOST_PP_CAT(t, n)
#define BOOST_TYPE_ERASURE_VTABLE_INIT(z, n, data) \
BOOST_PP_CAT(data, n)::value
#define BOOST_TYPE_ERASURE_AT(z, n, data) \
typename ::boost::mpl::at_c<data, n>::type
#define BOOST_TYPE_ERASURE_CONVERT_ELEMENT(z, n, data) \
BOOST_PP_CAT(t, n) = src.lookup( \
(typename ::boost::type_erasure::detail::rebind_placeholders< \
BOOST_PP_CAT(T, n), Bindings \
>::type*)0 \
);
#if N != 0
template<BOOST_PP_ENUM_PARAMS(N, class T)>
#else
template<class D = void>
#endif
struct BOOST_PP_CAT(vtable_storage, N)
{
BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_VTABLE_ENTRY, ~)
template<class Bindings, class Src>
void convert_from(const Src& BOOST_PP_EXPR_IF(N, src))
{
BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_CONVERT_ELEMENT, ~)
}
bool operator==(const BOOST_PP_CAT(vtable_storage, N)& BOOST_PP_EXPR_IF(N, other)) const
{ return true BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_VTABLE_COMPARE, ~); }
};
template<>
struct make_vtable_impl<N>
{
template<class Seq>
struct apply
{
typedef ::boost::type_erasure::detail::BOOST_PP_CAT(vtable_storage, N)<
BOOST_PP_ENUM(N, BOOST_TYPE_ERASURE_AT, Seq)
> type;
};
};
template<class Table BOOST_PP_ENUM_TRAILING_PARAMS(N, class T)>
struct BOOST_PP_CAT(vtable_init, N)
{
static const Table value;
};
template<class Table BOOST_PP_ENUM_TRAILING_PARAMS(N, class T)>
const Table BOOST_PP_CAT(vtable_init, N)<
Table BOOST_PP_ENUM_TRAILING_PARAMS(N, T)>::value =
{
BOOST_PP_ENUM(N, BOOST_TYPE_ERASURE_VTABLE_INIT, T)
};
template<>
struct make_vtable_init_impl<N>
{
template<class Seq, class Table>
struct apply
{
typedef ::boost::type_erasure::detail::BOOST_PP_CAT(vtable_init, N)<
Table
BOOST_PP_ENUM_TRAILING(N, BOOST_TYPE_ERASURE_AT, Seq)
> type;
};
};
#undef BOOST_TYPE_ERASURE_CONVERT_ELEMENT
#undef BOOST_TYPE_ERASURE_AT
#undef BOOST_TYPE_ERASURE_VTABLE_INIT
#undef BOOST_TYPE_ERASURE_VTABLE_COMPARE
#undef BOOST_TYPE_ERASURE_VTABLE_ENTRY
#undef N
#endif