Chris@101: /* Copyright 2003-2013 Joaquin M Lopez Munoz.
Chris@16:  * Distributed under the Boost Software License, Version 1.0.
Chris@16:  * (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:  * http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  *
Chris@16:  * See http://www.boost.org/libs/multi_index for library home page.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_MULTI_INDEX_GLOBAL_FUN_HPP
Chris@16: #define BOOST_MULTI_INDEX_GLOBAL_FUN_HPP
Chris@16: 
Chris@101: #if defined(_MSC_VER)
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/type_traits/is_const.hpp>
Chris@16: #include <boost/type_traits/is_reference.hpp>
Chris@16: #include <boost/type_traits/remove_const.hpp>
Chris@16: #include <boost/type_traits/remove_reference.hpp>
Chris@16: #include <boost/utility/enable_if.hpp>
Chris@16: 
Chris@16: #if !defined(BOOST_NO_SFINAE)
Chris@16: #include <boost/type_traits/is_convertible.hpp>
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost{
Chris@16: 
Chris@16: template<class T> class reference_wrapper; /* fwd decl. */
Chris@16: 
Chris@16: namespace multi_index{
Chris@16: 
Chris@16: namespace detail{
Chris@16: 
Chris@16: /* global_fun is a read-only key extractor from Value based on a given global
Chris@16:  * (or static member) function with signature:
Chris@16:  *
Chris@16:  *   Type f([const] Value [&]);
Chris@16:  *
Chris@16:  * Additionally, global_fun  and const_global_fun are overloaded to support
Chris@16:  * referece_wrappers of Value and "chained pointers" to Value's. By chained
Chris@16:  * pointer to T we  mean a type P such that, given a p of Type P
Chris@16:  *   *...n...*x is convertible to T&, for some n>=1.
Chris@16:  * Examples of chained pointers are raw and smart pointers, iterators and
Chris@16:  * arbitrary combinations of these (vg. T** or auto_ptr<T*>.)
Chris@16:  */
Chris@16: 
Chris@16: template<class Value,typename Type,Type (*PtrToFunction)(Value)>
Chris@16: struct const_ref_global_fun_base
Chris@16: {
Chris@16:   typedef typename remove_reference<Type>::type result_type;
Chris@16: 
Chris@16:   template<typename ChainedPtr>
Chris@16: 
Chris@16: #if !defined(BOOST_NO_SFINAE)
Chris@16:   typename disable_if<
Chris@16:     is_convertible<const ChainedPtr&,Value>,Type>::type
Chris@16: #else
Chris@16:   Type
Chris@16: #endif
Chris@16: 
Chris@16:   operator()(const ChainedPtr& x)const
Chris@16:   {
Chris@16:     return operator()(*x);
Chris@16:   }
Chris@16: 
Chris@16:   Type operator()(Value x)const
Chris@16:   {
Chris@16:     return PtrToFunction(x);
Chris@16:   }
Chris@16: 
Chris@16:   Type operator()(
Chris@16:     const reference_wrapper<
Chris@16:       typename remove_reference<Value>::type>& x)const
Chris@16:   { 
Chris@16:     return operator()(x.get());
Chris@16:   }
Chris@16: 
Chris@16:   Type operator()(
Chris@16:     const reference_wrapper<
Chris@16:       typename remove_const<
Chris@101:         typename remove_reference<Value>::type>::type>& x)const
Chris@16:   { 
Chris@16:     return operator()(x.get());
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: template<class Value,typename Type,Type (*PtrToFunction)(Value)>
Chris@16: struct non_const_ref_global_fun_base
Chris@16: {
Chris@16:   typedef typename remove_reference<Type>::type result_type;
Chris@16: 
Chris@16:   template<typename ChainedPtr>
Chris@16: 
Chris@16: #if !defined(BOOST_NO_SFINAE)
Chris@16:   typename disable_if<
Chris@16:     is_convertible<ChainedPtr&,Value>,Type>::type
Chris@16: #else
Chris@16:   Type
Chris@16: #endif
Chris@16: 
Chris@16:   operator()(const ChainedPtr& x)const
Chris@16:   {
Chris@16:     return operator()(*x);
Chris@16:   }
Chris@16: 
Chris@16:   Type operator()(Value x)const
Chris@16:   {
Chris@16:     return PtrToFunction(x);
Chris@16:   }
Chris@16: 
Chris@16:   Type operator()(
Chris@16:     const reference_wrapper<
Chris@16:       typename remove_reference<Value>::type>& x)const
Chris@16:   { 
Chris@16:     return operator()(x.get());
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: template<class Value,typename Type,Type (*PtrToFunction)(Value)>
Chris@16: struct non_ref_global_fun_base
Chris@16: {
Chris@16:   typedef typename remove_reference<Type>::type result_type;
Chris@16: 
Chris@16:   template<typename ChainedPtr>
Chris@16: 
Chris@16: #if !defined(BOOST_NO_SFINAE)
Chris@16:   typename disable_if<
Chris@16:     is_convertible<const ChainedPtr&,const Value&>,Type>::type
Chris@16: #else
Chris@16:   Type
Chris@16: #endif
Chris@16: 
Chris@16:   operator()(const ChainedPtr& x)const
Chris@16:   {
Chris@16:     return operator()(*x);
Chris@16:   }
Chris@16: 
Chris@16:   Type operator()(const Value& x)const
Chris@16:   {
Chris@16:     return PtrToFunction(x);
Chris@16:   }
Chris@16: 
Chris@16:   Type operator()(const reference_wrapper<const Value>& x)const
Chris@16:   { 
Chris@16:     return operator()(x.get());
Chris@16:   }
Chris@16: 
Chris@16:   Type operator()(
Chris@101:     const reference_wrapper<typename remove_const<Value>::type>& x)const
Chris@16:   { 
Chris@16:     return operator()(x.get());
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: } /* namespace multi_index::detail */
Chris@16: 
Chris@16: template<class Value,typename Type,Type (*PtrToFunction)(Value)>
Chris@16: struct global_fun:
Chris@16:   mpl::if_c<
Chris@16:     is_reference<Value>::value,
Chris@16:     typename mpl::if_c<
Chris@16:       is_const<typename remove_reference<Value>::type>::value,
Chris@16:       detail::const_ref_global_fun_base<Value,Type,PtrToFunction>,
Chris@16:       detail::non_const_ref_global_fun_base<Value,Type,PtrToFunction>
Chris@16:     >::type,
Chris@16:     detail::non_ref_global_fun_base<Value,Type,PtrToFunction>
Chris@16:   >::type
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: } /* namespace multi_index */
Chris@16: 
Chris@16: } /* namespace boost */
Chris@16: 
Chris@16: #endif