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/* Copyright 2006-2014 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_DETAIL_PERFECT_FWD_HPP
#define BOOST_FLYWEIGHT_DETAIL_PERFECT_FWD_HPP
#if defined(_MSC_VER)
#pragma once
#endif
/* C++03-compatible implementation of perfect forwarding.
* Usage:
*
* # define NAME ...
* # define BODY(args) {...BOOST_FLYWEIGHT_FORWARD(args)...}
* BOOST_FLYWEIGHT_PERFECT_FWD(name,body)
*
* where NAME includes the return type and qualifiers (if any) and BODY(args)
* is expected to fo the forwarding through BOOST_FLYWEIGHT_FORWARD(args).
*
* In compilers capable of perfect forwarding, the real thing is provided
* (just one variadic args overload is generated). Otherwise the machinery
* generates n+1 overloads, if rvalue refs are supported, or else 2^(n+1)-1
* overloads accepting any combination of lvalue refs and const lvalue refs,
* up to BOOST_FLYWEIGHT_LIMIT_PERFECT_FWD_ARGS args.
*
* BOOST_FLYWEIGHT_PERFECT_FWD_WITH_ARGS(name,body) is a variation omitting the
* overloads with zero args --when perfect forwarding is available, this second
* macro is exactly the same as the original.
*/
#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/repetition/enum.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/seq/seq.hpp>
#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
#include <utility>
#endif
#define BOOST_FLYWEIGHT_FORWARD_FORWARD_AUX(z,n,_) \
std::forward<BOOST_PP_CAT(T,n)>(BOOST_PP_CAT(t,n))
#define BOOST_FLYWEIGHT_FORWARD_FORWARD(n) \
BOOST_PP_ENUM(n,BOOST_FLYWEIGHT_FORWARD_FORWARD_AUX,~)
#define BOOST_FLYWEIGHT_FORWARD_ENUM(n) BOOST_PP_ENUM_PARAMS(n,t)
#define BOOST_FLYWEIGHT_FORWARD_PASS(arg) arg
#define BOOST_FLYWEIGHT_FORWARD(args)\
BOOST_PP_CAT(BOOST_FLYWEIGHT_FORWARD_,BOOST_PP_SEQ_HEAD(args))( \
BOOST_PP_SEQ_HEAD(BOOST_PP_SEQ_TAIL(args)))
#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)||\
defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
#if !defined(BOOST_FLYWEIGHT_LIMIT_PERFECT_FWD_ARGS)
#define BOOST_FLYWEIGHT_LIMIT_PERFECT_FWD_ARGS 5
#endif
#if BOOST_FLYWEIGHT_LIMIT_PERFECT_FWD_ARGS<0
#error BOOST_FLYWEIGHT_LIMIT_PERFECT_FWD_ARGS must be >=0
#endif
#if BOOST_FLYWEIGHT_LIMIT_PERFECT_FWD_ARGS<=5
#include <boost/flyweight/detail/pp_perfect_fwd.hpp>
#else
#include <boost/flyweight/detail/dyn_perfect_fwd.hpp>
#endif
#else
/* real perfect forwarding */
#define BOOST_FLYWEIGHT_PERFECT_FWD(name,body) \
template<typename... Args>name(Args&&... args) \
body((PASS)(std::forward<Args>(args)...))
#define BOOST_FLYWEIGHT_PERFECT_FWD_WITH_ARGS \
BOOST_FLYWEIGHT_PERFECT_FWD
#endif
#endif
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