/*
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Helper class used by variadic implementation of variadic boost::signals2::signal.
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Author: Frank Mori Hess <fmhess@users.sourceforge.net>
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Begin: 2009-05-27
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*/
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// Copyright Frank Mori Hess 2009
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// Use, modification and
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// distribution is subject to the Boost Software License, Version
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// 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// For more information, see http://www.boost.org
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#ifndef BOOST_SIGNALS2_DETAIL_VARIADIC_SLOT_INVOKER_HPP
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#define BOOST_SIGNALS2_DETAIL_VARIADIC_SLOT_INVOKER_HPP
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#include <boost/mpl/size_t.hpp>
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#include <boost/signals2/detail/variadic_arg_type.hpp>
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// if compiler has std::tuple use it instead of boost::tuple
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// because boost::tuple does not have variadic template support at present.
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#ifdef BOOST_NO_CXX11_HDR_TUPLE
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#include <boost/tuple/tuple.hpp>
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#define BOOST_SIGNALS2_TUPLE boost::tuple
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#define BOOST_SIGNALS2_GET boost::get
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#else
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#include <tuple>
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#define BOOST_SIGNALS2_TUPLE std::tuple
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#define BOOST_SIGNALS2_GET std::get
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#endif
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// vc12 seems to erroneously report formal parameters as unreferenced (warning C4100)
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// if parameters of variadic template functions are only referenced by calling
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// other varadic template functions. silence these warnings:
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#if defined(BOOST_MSVC)
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#pragma warning(push)
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#if BOOST_MSVC >= 1800
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#pragma warning(disable:4100)
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#endif
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#endif
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namespace boost
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{
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namespace signals2
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{
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namespace detail
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{
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template<unsigned ... values> class unsigned_meta_array {};
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template<typename UnsignedMetaArray, unsigned n> class unsigned_meta_array_appender;
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template<unsigned n, unsigned ... Args>
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class unsigned_meta_array_appender<unsigned_meta_array<Args...>, n>
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{
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public:
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typedef unsigned_meta_array<Args..., n> type;
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};
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template<unsigned n> class make_unsigned_meta_array;
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template<> class make_unsigned_meta_array<0>
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{
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public:
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typedef unsigned_meta_array<> type;
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};
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template<> class make_unsigned_meta_array<1>
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{
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public:
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typedef unsigned_meta_array<0> type;
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};
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template<unsigned n> class make_unsigned_meta_array
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{
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public:
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typedef typename unsigned_meta_array_appender<typename make_unsigned_meta_array<n-1>::type, n - 1>::type type;
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};
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template<typename R>
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class call_with_tuple_args
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{
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public:
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typedef R result_type;
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template<typename Func, typename ... Args, std::size_t N>
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R operator()(Func &func, const BOOST_SIGNALS2_TUPLE<Args...> & args, mpl::size_t<N>) const
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{
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typedef typename make_unsigned_meta_array<N>::type indices_type;
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return m_invoke<Func>(func, indices_type(), args);
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}
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private:
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template<typename Func, unsigned ... indices, typename ... Args>
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R m_invoke(Func &func, unsigned_meta_array<indices...>, const BOOST_SIGNALS2_TUPLE<Args...> & args,
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typename boost::disable_if<boost::is_void<typename Func::result_type> >::type * = 0
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) const
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{
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return func(BOOST_SIGNALS2_GET<indices>(args)...);
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}
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template<typename Func, unsigned ... indices, typename ... Args>
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R m_invoke(Func &func, unsigned_meta_array<indices...>, const BOOST_SIGNALS2_TUPLE<Args...> & args,
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typename boost::enable_if<boost::is_void<typename Func::result_type> >::type * = 0
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) const
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{
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func(BOOST_SIGNALS2_GET<indices>(args)...);
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return R();
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}
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// This overload is redundant, as it is the same as the previous variadic method when
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// it has zero "indices" or "Args" variadic template parameters. This overload
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// only exists to quiet some unused parameter warnings
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// on certain compilers (some versions of gcc and msvc)
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template<typename Func>
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R m_invoke(Func &func, unsigned_meta_array<>, const BOOST_SIGNALS2_TUPLE<> &,
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typename boost::enable_if<boost::is_void<typename Func::result_type> >::type * = 0
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) const
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{
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func();
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return R();
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}
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};
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template<typename R, typename ... Args>
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class variadic_slot_invoker
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{
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public:
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typedef R result_type;
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variadic_slot_invoker(Args & ... args): _args(args...)
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{}
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template<typename ConnectionBodyType>
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result_type operator ()(const ConnectionBodyType &connectionBody) const
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{
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return call_with_tuple_args<result_type>()(connectionBody->slot().slot_function(),
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_args, mpl::size_t<sizeof...(Args)>());
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}
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private:
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BOOST_SIGNALS2_TUPLE<Args& ...> _args;
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};
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} // namespace detail
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} // namespace signals2
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} // namespace boost
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#if defined(BOOST_MSVC)
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#pragma warning(pop)
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#endif
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#endif // BOOST_SIGNALS2_DETAIL_VARIADIC_SLOT_INVOKER_HPP
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