| /* 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 |