flyweight/detail/default_value_policy.hpp

0001 /* Copyright 2006-2019 Joaquin M Lopez Munoz.
0002  * Distributed under the Boost Software License, Version 1.0.
0003  * (See accompanying file LICENSE_1_0.txt or copy at
0004  * http://www.boost.org/LICENSE_1_0.txt)
0005  *
0006  * See http://www.boost.org/libs/flyweight for library home page.
0007  */
0008
0009 #ifndef BOOST_FLYWEIGHT_DETAIL_DEFAULT_VALUE_POLICY_HPP
0010 #define BOOST_FLYWEIGHT_DETAIL_DEFAULT_VALUE_POLICY_HPP
0011
0012 #if defined(_MSC_VER)
0013 #pragma once
0014 #endif
0015
0016 #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
0017 #include <boost/detail/workaround.hpp>
0018 #include <boost/flyweight/detail/perfect_fwd.hpp>
0019 #include <boost/flyweight/detail/value_tag.hpp>
0020
0021 /* Default value policy: the key is the same as the value.
0022  */
0023
0024 namespace boost{
0025
0026 namespace flyweights{
0027
0028 namespace detail{
0029
0030 template<typename Value>
0031 struct default_value_policy:value_marker
0032 {
0033   typedef Value key_type;
0034   typedef Value value_type;
0035
0036   struct rep_type
0037   {
0038   /* template ctors */
0039
0040 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)&&\
0041     !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)&&\
0042     BOOST_WORKAROUND(BOOST_GCC,<=40603)
0043 /* GCC bug: the default ctor generated by the variadic template ctor below
0044  * fails to value-initialize x.
0045  */
0046
0047     rep_type():x(){}
0048 #endif
0049
0050 #define BOOST_FLYWEIGHT_PERFECT_FWD_CTR_BODY(args) \
0051   :x(BOOST_FLYWEIGHT_FORWARD(args)){}
0052
0053   BOOST_FLYWEIGHT_PERFECT_FWD(
0054     explicit rep_type,
0055     BOOST_FLYWEIGHT_PERFECT_FWD_CTR_BODY)
0056
0057 #undef BOOST_FLYWEIGHT_PERFECT_FWD_CTR_BODY
0058
0059     rep_type(const rep_type& r):x(r.x){}
0060
0061 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
0062     rep_type(rep_type&& r):x(std::move(r.x)){}
0063 #endif
0064
0065     operator const value_type&()const{return x;}
0066
0067     value_type x;
0068   };
0069
0070   static void construct_value(const rep_type&){}
0071   static void copy_value(const rep_type&){}
0072
0073 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
0074   static void move_value(const rep_type&){}
0075 #endif
0076 };
0077
0078 } /* namespace flyweights::detail */
0079
0080 } /* namespace flyweights */
0081
0082 } /* namespace boost */
0083
0084 #endif