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/*=============================================================================
Copyright (c) 2007 Tobias Schwinger
Use modification and distribution are subject to 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).
==============================================================================*/
#ifndef BOOST_FUNCTIONAL_LIGHTWEIGHT_FORWARD_ADAPTER_HPP_INCLUDED
# ifndef BOOST_PP_IS_ITERATING
# include <boost/config.hpp>
# include <boost/detail/workaround.hpp>
# include <boost/preprocessor/cat.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_binary_params.hpp>
# include <boost/preprocessor/facilities/intercept.hpp>
# include <boost/utility/result_of.hpp>
# include <boost/ref.hpp>
# ifndef BOOST_FUNCTIONAL_LIGHTWEIGHT_FORWARD_ADAPTER_MAX_ARITY
# define BOOST_FUNCTIONAL_LIGHTWEIGHT_FORWARD_ADAPTER_MAX_ARITY 10
# elif BOOST_FUNCTIONAL_FORDWARD_ADAPTER_MAX_ARITY < 3
# undef BOOST_FUNCTIONAL_LIGHTWEIGHT_FORWARD_ADAPTER_MAX_ARITY
# define BOOST_FUNCTIONAL_LIGHTWEIGHT_FORWARD_ADAPTER_MAX_ARITY 3
# endif
namespace boost
{
template< typename Function, int Arity_Or_MinArity = -1, int MaxArity = -1 >
class lightweight_forward_adapter;
//----- ---- --- -- - - - -
namespace detail
{
template< class MostDerived, typename Function, typename FunctionConst,
int Arity, int MinArity >
struct lightweight_forward_adapter_impl;
struct lightweight_forward_adapter_result
{
template< typename Sig > struct apply;
// Utility metafunction for argument transform
template< typename T > struct x { typedef T const& t; };
template< typename T > struct x< boost::reference_wrapper<T> >
{ typedef T& t; };
template< typename T > struct x<T&> : x<T> { };
template< typename T > struct x<T const&> : x<T> { };
template< typename T > struct x<T const> : x<T> { };
// Utility metafunction to choose target function qualification
template< typename T > struct c
{ typedef typename T::target_function_t t; };
template< typename T > struct c<T& >
{ typedef typename T::target_function_t t; };
template< typename T > struct c<T const >
{ typedef typename T::target_function_const_t t; };
template< typename T > struct c<T const&>
{ typedef typename T::target_function_const_t t; };
};
}
# define BOOST_TMP_MACRO(f,fn,fc) \
boost::detail::lightweight_forward_adapter_impl< \
lightweight_forward_adapter<f,Arity_Or_MinArity,MaxArity>, fn, fc, \
(MaxArity!=-1? MaxArity :Arity_Or_MinArity!=-1? Arity_Or_MinArity \
:BOOST_FUNCTIONAL_LIGHTWEIGHT_FORWARD_ADAPTER_MAX_ARITY), \
(Arity_Or_MinArity!=-1? Arity_Or_MinArity : 0) >
template< typename Function, int Arity_Or_MinArity, int MaxArity >
class lightweight_forward_adapter
: public BOOST_TMP_MACRO(Function,Function,Function const)
, private Function
{
public:
lightweight_forward_adapter(Function const& f = Function())
: Function(f)
{ }
typedef Function target_function_t;
typedef Function const target_function_const_t;
Function & target_function() { return *this; }
Function const & target_function() const { return *this; }
template< typename Sig > struct result
: detail::lightweight_forward_adapter_result::template apply<Sig>
{ };
using BOOST_TMP_MACRO(Function,Function, Function const)::operator();
};
template< typename Function, int Arity_Or_MinArity, int MaxArity >
class lightweight_forward_adapter< Function const, Arity_Or_MinArity,
MaxArity >
: public BOOST_TMP_MACRO(Function const, Function const, Function const)
, private Function
{
public:
lightweight_forward_adapter(Function const& f = Function())
: Function(f)
{ }
typedef Function const target_function_t;
typedef Function const target_function_const_t;
Function const & target_function() const { return *this; }
template< typename Sig > struct result
: detail::lightweight_forward_adapter_result::template apply<Sig>
{ };
using BOOST_TMP_MACRO(Function const,Function const, Function const)
::operator();
};
template< typename Function, int Arity_Or_MinArity, int MaxArity >
class lightweight_forward_adapter< Function &, Arity_Or_MinArity, MaxArity >
: public BOOST_TMP_MACRO(Function&, Function, Function)
{
Function& ref_function;
public:
lightweight_forward_adapter(Function& f)
: ref_function(f)
{ }
typedef Function target_function_t;
typedef Function target_function_const_t;
Function & target_function() const { return this->ref_function; }
template< typename Sig > struct result
: detail::lightweight_forward_adapter_result::template apply<Sig>
{ };
using BOOST_TMP_MACRO(Function&, Function, Function)::operator();
};
#undef BOOST_TMP_MACRO
namespace detail
{
template< class Self >
struct lightweight_forward_adapter_result::apply< Self() >
: boost::result_of< BOOST_DEDUCED_TYPENAME c<Self>::t() >
{ };
// When operator() doesn't have any parameters, it can't
// be templatized and can't use SFINAE, so intead use class
// template parameter SFINAE to decide whether to instantiate it.
template <typename T, typename R = void>
struct lightweight_forward_adapter_sfinae
{
typedef T type;
};
// This is the fallback for when there isn't an operator()(),
// need to create an operator() that will never instantiate
// so that using parent::operator() will work okay.
template< class MD, class F, class FC, class Enable = void>
struct lightweight_forward_adapter_impl_zero
: lightweight_forward_adapter_result
{
template <typename T> struct never_instantiate {};
template <typename T>
typename never_instantiate<T>::type operator()(T) const {}
};
template< class MD, class F, class FC>
struct lightweight_forward_adapter_impl_zero<MD, F, FC,
typename lightweight_forward_adapter_sfinae<typename boost::result_of< FC() >::type>::type>
: lightweight_forward_adapter_result
{
inline typename boost::result_of< FC() >::type
operator()() const
{
return static_cast<MD const*>(this)->target_function()();
}
inline typename boost::result_of< F() >::type
operator()()
{
return static_cast<MD*>(this)->target_function()();
}
};
template< class MD, class F, class FC >
struct lightweight_forward_adapter_impl<MD,F,FC,0,0>
: lightweight_forward_adapter_impl_zero<MD,F,FC>
{
};
# define BOOST_PP_FILENAME_1 \
<boost/functional/lightweight_forward_adapter.hpp>
# define BOOST_PP_ITERATION_LIMITS \
(1,BOOST_FUNCTIONAL_LIGHTWEIGHT_FORWARD_ADAPTER_MAX_ARITY)
# include BOOST_PP_ITERATE()
} // namespace detail
template<class F, int A0, int A1>
struct result_of<boost::lightweight_forward_adapter<F,A0,A1> const ()>
: boost::detail::lightweight_forward_adapter_result::template apply<
boost::lightweight_forward_adapter<F,A0,A1> const () >
{ };
template<class F, int A0, int A1>
struct result_of<boost::lightweight_forward_adapter<F,A0,A1>()>
: boost::detail::lightweight_forward_adapter_result::template apply<
boost::lightweight_forward_adapter<F,A0,A1>() >
{ };
template<class F, int A0, int A1>
struct result_of<boost::lightweight_forward_adapter<F,A0,A1> const& ()>
: boost::detail::lightweight_forward_adapter_result::template apply<
boost::lightweight_forward_adapter<F,A0,A1> const () >
{ };
template<class F, int A0, int A1>
struct result_of<boost::lightweight_forward_adapter<F,A0,A1>& ()>
: boost::detail::lightweight_forward_adapter_result::template apply<
boost::lightweight_forward_adapter<F,A0,A1>() >
{ };
}
# define BOOST_FUNCTIONAL_LIGHTWEIGHT_FORWARD_ADAPTER_HPP_INCLUDED
# else // defined(BOOST_PP_IS_ITERATING)
# define N BOOST_PP_ITERATION()
template< class Self, BOOST_PP_ENUM_PARAMS(N,typename T) >
struct lightweight_forward_adapter_result::apply<
Self (BOOST_PP_ENUM_PARAMS(N,T)) >
: boost::result_of<
BOOST_DEDUCED_TYPENAME c<Self>::t (BOOST_PP_ENUM_BINARY_PARAMS(N,
typename x<T,>::t BOOST_PP_INTERCEPT)) >
{ };
template< class MD, class F, class FC >
struct lightweight_forward_adapter_impl<MD,F,FC,BOOST_PP_DEC(N),N>
: lightweight_forward_adapter_result
{
template< BOOST_PP_ENUM_PARAMS(N,typename T) >
inline typename boost::result_of< F(BOOST_PP_ENUM_BINARY_PARAMS(N,
T,const& BOOST_PP_INTERCEPT)) >::type
operator()(BOOST_PP_ENUM_BINARY_PARAMS(N,T,& BOOST_PP_INTERCEPT));
};
template< class MD, class F, class FC, int MinArity >
struct lightweight_forward_adapter_impl<MD,F,FC,N,MinArity>
: lightweight_forward_adapter_impl<MD,F,FC,BOOST_PP_DEC(N),MinArity>
{
using lightweight_forward_adapter_impl<MD,F,FC,BOOST_PP_DEC(N),
MinArity>::operator();
# define M(z,i,d) \
static_cast<typename d::template x<T##i>::t>(a##i)
template< BOOST_PP_ENUM_PARAMS(N,typename T) >
inline typename lightweight_forward_adapter_result::template apply<
MD const (BOOST_PP_ENUM_BINARY_PARAMS(N,
T,const& BOOST_PP_INTERCEPT)) >::type
operator()(BOOST_PP_ENUM_BINARY_PARAMS(N,T,const& a)) const
{
typedef lightweight_forward_adapter_result _;
return static_cast<MD const*>(this)->target_function()(
BOOST_PP_ENUM(N,M,_));
}
template< BOOST_PP_ENUM_PARAMS(N,typename T) >
inline typename lightweight_forward_adapter_result::template apply<
MD (BOOST_PP_ENUM_BINARY_PARAMS(N,
T,const& BOOST_PP_INTERCEPT)) >::type
operator()(BOOST_PP_ENUM_BINARY_PARAMS(N,T,const& a))
{
typedef lightweight_forward_adapter_result _;
return static_cast<MD*>(this)->target_function()(
BOOST_PP_ENUM(N,M,_));
}
# undef M
};
# undef N
# endif // defined(BOOST_PP_IS_ITERATING)
#endif // include guard
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