williamr@2: /* Copyright 2003-2006 Joaquín M López Muñoz.
williamr@2:  * Distributed under the Boost Software License, Version 1.0.
williamr@2:  * (See accompanying file LICENSE_1_0.txt or copy at
williamr@2:  * http://www.boost.org/LICENSE_1_0.txt)
williamr@2:  *
williamr@2:  * See http://www.boost.org/libs/multi_index for library home page.
williamr@2:  */
williamr@2: 
williamr@2: #ifndef BOOST_MULTI_INDEX_MEMBER_HPP
williamr@2: #define BOOST_MULTI_INDEX_MEMBER_HPP
williamr@2: 
williamr@2: #if defined(_MSC_VER)&&(_MSC_VER>=1200)
williamr@2: #pragma once
williamr@2: #endif
williamr@2: 
williamr@2: #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
williamr@2: #include <boost/mpl/if.hpp>
williamr@2: #include <boost/type_traits/is_const.hpp>
williamr@2: #include <boost/utility/enable_if.hpp>
williamr@2: #include <cstddef>
williamr@2: 
williamr@2: #if !defined(BOOST_NO_SFINAE)
williamr@2: #include <boost/type_traits/is_convertible.hpp>
williamr@2: #endif
williamr@2: 
williamr@2: namespace boost{
williamr@2: 
williamr@2: template<class T> class reference_wrapper; /* fwd decl. */
williamr@2: 
williamr@2: namespace multi_index{
williamr@2: 
williamr@2: namespace detail{
williamr@2: 
williamr@2: /* member is a read/write key extractor for accessing a given
williamr@2:  * member of a class.
williamr@2:  * Additionally, member is overloaded to support referece_wrappers
williamr@2:  * of T and "chained pointers" to T's. By chained pointer to T we mean
williamr@2:  * a type P  such that, given a p of Type P
williamr@2:  *   *...n...*x is convertible to T&, for some n>=1.
williamr@2:  * Examples of chained pointers are raw and smart pointers, iterators and
williamr@2:  * arbitrary combinations of these (vg. T** or auto_ptr<T*>.)
williamr@2:  */
williamr@2: 
williamr@2: /* NB. Some overloads of operator() have an extra dummy parameter int=0.
williamr@2:  * This disambiguator serves several purposes:
williamr@2:  *  - Without it, MSVC++ 6.0 incorrectly regards some overloads as
williamr@2:  *    specializations of a previous member function template.
williamr@2:  *  - MSVC++ 6.0/7.0 seem to incorrectly treat some different memfuns
williamr@2:  *    as if they have the same signature.
williamr@2:  *  - If remove_const is broken due to lack of PTS, int=0 avoids the
williamr@2:  *    declaration of memfuns with identical signature.
williamr@2:  */
williamr@2: 
williamr@2: template<class Class,typename Type,Type Class::*PtrToMember>
williamr@2: struct const_member_base
williamr@2: {
williamr@2:   typedef Type result_type;
williamr@2: 
williamr@2:   template<typename ChainedPtr>
williamr@2: 
williamr@2: #if !defined(BOOST_NO_SFINAE)
williamr@2:   typename disable_if<
williamr@2:     is_convertible<const ChainedPtr&,const Class&>,Type&>::type
williamr@2: #else
williamr@2:   Type&
williamr@2: #endif
williamr@2:   
williamr@2:   operator()(const ChainedPtr& x)const
williamr@2:   {
williamr@2:     return operator()(*x);
williamr@2:   }
williamr@2: 
williamr@2:   Type& operator()(const Class& x)const
williamr@2:   {
williamr@2:     return x.*PtrToMember;
williamr@2:   }
williamr@2: 
williamr@2:   Type& operator()(const reference_wrapper<const Class>& x)const
williamr@2:   {
williamr@2:     return operator()(x.get());
williamr@2:   }
williamr@2: 
williamr@2:   Type& operator()(const reference_wrapper<Class>& x,int=0)const
williamr@2:   { 
williamr@2:     return operator()(x.get());
williamr@2:   }
williamr@2: };
williamr@2: 
williamr@2: template<class Class,typename Type,Type Class::*PtrToMember>
williamr@2: struct non_const_member_base
williamr@2: {
williamr@2:   typedef Type result_type;
williamr@2: 
williamr@2:   template<typename ChainedPtr>
williamr@2: 
williamr@2: #if !defined(BOOST_NO_SFINAE)
williamr@2:   typename disable_if<
williamr@2:     is_convertible<const ChainedPtr&,const Class&>,Type&>::type
williamr@2: #else
williamr@2:   Type&
williamr@2: #endif
williamr@2: 
williamr@2:   operator()(const ChainedPtr& x)const
williamr@2:   {
williamr@2:     return operator()(*x);
williamr@2:   }
williamr@2: 
williamr@2:   const Type& operator()(const Class& x,int=0)const
williamr@2:   {
williamr@2:     return x.*PtrToMember;
williamr@2:   }
williamr@2: 
williamr@2:   Type& operator()(Class& x)const
williamr@2:   { 
williamr@2:     return x.*PtrToMember;
williamr@2:   }
williamr@2: 
williamr@2:   const Type& operator()(const reference_wrapper<const Class>& x,int=0)const
williamr@2:   {
williamr@2:     return operator()(x.get());
williamr@2:   }
williamr@2: 
williamr@2:   Type& operator()(const reference_wrapper<Class>& x)const
williamr@2:   { 
williamr@2:     return operator()(x.get());
williamr@2:   }
williamr@2: };
williamr@2: 
williamr@2: } /* namespace multi_index::detail */
williamr@2: 
williamr@2: template<class Class,typename Type,Type Class::*PtrToMember>
williamr@2: struct member:
williamr@2:   mpl::if_c<
williamr@2:     is_const<Type>::value,
williamr@2:     detail::const_member_base<Class,Type,PtrToMember>,
williamr@2:     detail::non_const_member_base<Class,Type,PtrToMember>
williamr@2:   >::type
williamr@2: {
williamr@2: };
williamr@2: 
williamr@2: namespace detail{
williamr@2: 
williamr@2: /* MSVC++ 6.0 does not support properly pointers to members as
williamr@2:  * non-type template arguments, as reported in
williamr@2:  *   http://support.microsoft.com/default.aspx?scid=kb;EN-US;249045
williamr@2:  * A similar problem (though not identical) is shown by MSVC++ 7.0.
williamr@2:  * We provide an alternative to member<> accepting offsets instead
williamr@2:  * of pointers to members. This happens to work even for non-POD
williamr@2:  * types (although the standard forbids use of offsetof on these),
williamr@2:  * so it serves as a workaround in this compiler for all practical
williamr@2:  * purposes.
williamr@2:  * Surprisingly enough, other compilers, like Intel C++ 7.0/7.1 and
williamr@2:  * Visual Age 6.0, have similar bugs. This replacement of member<>
williamr@2:  * can be used for them too.
williamr@2:  */
williamr@2: 
williamr@2: template<class Class,typename Type,std::size_t OffsetOfMember>
williamr@2: struct const_member_offset_base
williamr@2: {
williamr@2:   typedef Type result_type;
williamr@2: 
williamr@2:   template<typename ChainedPtr>
williamr@2: 
williamr@2: #if !defined(BOOST_NO_SFINAE)
williamr@2:   typename disable_if<
williamr@2:     is_convertible<const ChainedPtr&,const Class&>,Type&>::type
williamr@2: #else
williamr@2:   Type&
williamr@2: #endif 
williamr@2:     
williamr@2:   operator()(const ChainedPtr& x)const
williamr@2:   {
williamr@2:     return operator()(*x);
williamr@2:   }
williamr@2: 
williamr@2:   Type& operator()(const Class& x)const
williamr@2:   {
williamr@2:     return *static_cast<const Type*>(
williamr@2:       static_cast<const void*>(
williamr@2:         static_cast<const char*>(
williamr@2:           static_cast<const void *>(&x))+OffsetOfMember));
williamr@2:   }
williamr@2: 
williamr@2:   Type& operator()(const reference_wrapper<const Class>& x)const
williamr@2:   {
williamr@2:     return operator()(x.get());
williamr@2:   }
williamr@2: 
williamr@2:   Type& operator()(const reference_wrapper<Class>& x,int=0)const
williamr@2:   {
williamr@2:     return operator()(x.get());
williamr@2:   }
williamr@2: };
williamr@2: 
williamr@2: template<class Class,typename Type,std::size_t OffsetOfMember>
williamr@2: struct non_const_member_offset_base
williamr@2: {
williamr@2:   typedef Type result_type;
williamr@2: 
williamr@2:   template<typename ChainedPtr>
williamr@2: 
williamr@2: #if !defined(BOOST_NO_SFINAE)
williamr@2:   typename disable_if<
williamr@2:     is_convertible<const ChainedPtr&,const Class&>,Type&>::type
williamr@2: #else
williamr@2:   Type&
williamr@2: #endif 
williamr@2:   
williamr@2:   operator()(const ChainedPtr& x)const
williamr@2:   {
williamr@2:     return operator()(*x);
williamr@2:   }
williamr@2: 
williamr@2:   const Type& operator()(const Class& x,int=0)const
williamr@2:   {
williamr@2:     return *static_cast<const Type*>(
williamr@2:       static_cast<const void*>(
williamr@2:         static_cast<const char*>(
williamr@2:           static_cast<const void *>(&x))+OffsetOfMember));
williamr@2:   }
williamr@2: 
williamr@2:   Type& operator()(Class& x)const
williamr@2:   { 
williamr@2:     return *static_cast<Type*>(
williamr@2:       static_cast<void*>(
williamr@2:         static_cast<char*>(static_cast<void *>(&x))+OffsetOfMember));
williamr@2:   }
williamr@2: 
williamr@2:   const Type& operator()(const reference_wrapper<const Class>& x,int=0)const
williamr@2:   {
williamr@2:     return operator()(x.get());
williamr@2:   }
williamr@2: 
williamr@2:   Type& operator()(const reference_wrapper<Class>& x)const
williamr@2:   {
williamr@2:     return operator()(x.get());
williamr@2:   }
williamr@2: };
williamr@2: 
williamr@2: } /* namespace multi_index::detail */
williamr@2: 
williamr@2: template<class Class,typename Type,std::size_t OffsetOfMember>
williamr@2: struct member_offset:
williamr@2:   mpl::if_c<
williamr@2:     is_const<Type>::value,
williamr@2:     detail::const_member_offset_base<Class,Type,OffsetOfMember>,
williamr@2:     detail::non_const_member_offset_base<Class,Type,OffsetOfMember>
williamr@2:   >::type
williamr@2: {
williamr@2: };
williamr@2: 
williamr@2: /* BOOST_MULTI_INDEX_MEMBER resolves to member in the normal cases,
williamr@2:  * and to member_offset as a workaround in those defective compilers for
williamr@2:  * which BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS is defined.
williamr@2:  */
williamr@2: 
williamr@2: #if defined(BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS)
williamr@2: #define BOOST_MULTI_INDEX_MEMBER(Class,Type,MemberName) \
williamr@2: ::boost::multi_index::member_offset< Class,Type,offsetof(Class,MemberName) >
williamr@2: #else
williamr@2: #define BOOST_MULTI_INDEX_MEMBER(Class,Type,MemberName) \
williamr@2: ::boost::multi_index::member< Class,Type,&Class::MemberName >
williamr@2: #endif
williamr@2: 
williamr@2: } /* namespace multi_index */
williamr@2: 
williamr@2: } /* namespace boost */
williamr@2: 
williamr@2: #endif