src/thirdparty/boost_1_47_0/boost/multi_index/member.hpp

   1 /* Copyright 2003-2008 Joaquin M Lopez Munoz.
   2  * Distributed under the Boost Software License, Version 1.0.
   3  * (See accompanying file LICENSE_1_0.txt or copy at
   4  * http://www.boost.org/LICENSE_1_0.txt)
   5  *
   6  * See http://www.boost.org/libs/multi_index for library home page.
   7  */
   8
   9 #ifndef BOOST_MULTI_INDEX_MEMBER_HPP
  10 #define BOOST_MULTI_INDEX_MEMBER_HPP
  11
  12 #if defined(_MSC_VER)&&(_MSC_VER>=1200)
  13 #pragma once
  14 #endif
  15
  16 #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
  17 #include <boost/mpl/if.hpp>
  18 #include <boost/type_traits/is_const.hpp>
  19 #include <boost/utility/enable_if.hpp>
  20 #include <cstddef>
  21
  22 #if !defined(BOOST_NO_SFINAE)
  23 #include <boost/type_traits/is_convertible.hpp>
  24 #endif
  25
  26 namespace boost{
  27
  28 template<class T> class reference_wrapper; /* fwd decl. */
  29
  30 namespace multi_index{
  31
  32 namespace detail{
  33
  34 /* member is a read/write key extractor for accessing a given
  35  * member of a class.
  36  * Additionally, member is overloaded to support referece_wrappers
  37  * of T and "chained pointers" to T's. By chained pointer to T we mean
  38  * a type P  such that, given a p of Type P
  39  *   *...n...*x is convertible to T&, for some n>=1.
  40  * Examples of chained pointers are raw and smart pointers, iterators and
  41  * arbitrary combinations of these (vg. T** or auto_ptr<T*>.)
  42  */
  43
  44 /* NB. Some overloads of operator() have an extra dummy parameter int=0.
  45  * This disambiguator serves several purposes:
  46  *  - Without it, MSVC++ 6.0 incorrectly regards some overloads as
  47  *    specializations of a previous member function template.
  48  *  - MSVC++ 6.0/7.0 seem to incorrectly treat some different memfuns
  49  *    as if they have the same signature.
  50  *  - If remove_const is broken due to lack of PTS, int=0 avoids the
  51  *    declaration of memfuns with identical signature.
  52  */
  53
  54 template<class Class,typename Type,Type Class::*PtrToMember>
  55 struct const_member_base
  56 {
  57   typedef Type result_type;
  58
  59   template<typename ChainedPtr>
  60
  61 #if !defined(BOOST_NO_SFINAE)
  62   typename disable_if<
  63     is_convertible<const ChainedPtr&,const Class&>,Type&>::type
  64 #else
  65   Type&
  66 #endif
  67
  68   operator()(const ChainedPtr& x)const
  69   {
  70     return operator()(*x);
  71   }
  72
  73   Type& operator()(const Class& x)const
  74   {
  75     return x.*PtrToMember;
  76   }
  77
  78   Type& operator()(const reference_wrapper<const Class>& x)const
  79   {
  80     return operator()(x.get());
  81   }
  82
  83   Type& operator()(const reference_wrapper<Class>& x,int=0)const
  84   {
  85     return operator()(x.get());
  86   }
  87 };
  88
  89 template<class Class,typename Type,Type Class::*PtrToMember>
  90 struct non_const_member_base
  91 {
  92   typedef Type result_type;
  93
  94   template<typename ChainedPtr>
  95
  96 #if !defined(BOOST_NO_SFINAE)
  97   typename disable_if<
  98     is_convertible<const ChainedPtr&,const Class&>,Type&>::type
  99 #else
 100   Type&
 101 #endif
 102
 103   operator()(const ChainedPtr& x)const
 104   {
 105     return operator()(*x);
 106   }
 107
 108   const Type& operator()(const Class& x,int=0)const
 109   {
 110     return x.*PtrToMember;
 111   }
 112
 113   Type& operator()(Class& x)const
 114   {
 115     return x.*PtrToMember;
 116   }
 117
 118   const Type& operator()(const reference_wrapper<const Class>& x,int=0)const
 119   {
 120     return operator()(x.get());
 121   }
 122
 123   Type& operator()(const reference_wrapper<Class>& x)const
 124   {
 125     return operator()(x.get());
 126   }
 127 };
 128
 129 } /* namespace multi_index::detail */
 130
 131 template<class Class,typename Type,Type Class::*PtrToMember>
 132 struct member:
 133   mpl::if_c<
 134     is_const<Type>::value,
 135     detail::const_member_base<Class,Type,PtrToMember>,
 136     detail::non_const_member_base<Class,Type,PtrToMember>
 137   >::type
 138 {
 139 };
 140
 141 namespace detail{
 142
 143 /* MSVC++ 6.0 does not support properly pointers to members as
 144  * non-type template arguments, as reported in
 145  *   http://support.microsoft.com/default.aspx?scid=kb;EN-US;249045
 146  * A similar problem (though not identical) is shown by MSVC++ 7.0.
 147  * We provide an alternative to member<> accepting offsets instead
 148  * of pointers to members. This happens to work even for non-POD
 149  * types (although the standard forbids use of offsetof on these),
 150  * so it serves as a workaround in this compiler for all practical
 151  * purposes.
 152  * Surprisingly enough, other compilers, like Intel C++ 7.0/7.1 and
 153  * Visual Age 6.0, have similar bugs. This replacement of member<>
 154  * can be used for them too.
 155  */
 156
 157 template<class Class,typename Type,std::size_t OffsetOfMember>
 158 struct const_member_offset_base
 159 {
 160   typedef Type result_type;
 161
 162   template<typename ChainedPtr>
 163
 164 #if !defined(BOOST_NO_SFINAE)
 165   typename disable_if<
 166     is_convertible<const ChainedPtr&,const Class&>,Type&>::type
 167 #else
 168   Type&
 169 #endif
 170
 171   operator()(const ChainedPtr& x)const
 172   {
 173     return operator()(*x);
 174   }
 175
 176   Type& operator()(const Class& x)const
 177   {
 178     return *static_cast<const Type*>(
 179       static_cast<const void*>(
 180         static_cast<const char*>(
 181           static_cast<const void *>(&x))+OffsetOfMember));
 182   }
 183
 184   Type& operator()(const reference_wrapper<const Class>& x)const
 185   {
 186     return operator()(x.get());
 187   }
 188
 189   Type& operator()(const reference_wrapper<Class>& x,int=0)const
 190   {
 191     return operator()(x.get());
 192   }
 193 };
 194
 195 template<class Class,typename Type,std::size_t OffsetOfMember>
 196 struct non_const_member_offset_base
 197 {
 198   typedef Type result_type;
 199
 200   template<typename ChainedPtr>
 201
 202 #if !defined(BOOST_NO_SFINAE)
 203   typename disable_if<
 204     is_convertible<const ChainedPtr&,const Class&>,Type&>::type
 205 #else
 206   Type&
 207 #endif
 208
 209   operator()(const ChainedPtr& x)const
 210   {
 211     return operator()(*x);
 212   }
 213
 214   const Type& operator()(const Class& x,int=0)const
 215   {
 216     return *static_cast<const Type*>(
 217       static_cast<const void*>(
 218         static_cast<const char*>(
 219           static_cast<const void *>(&x))+OffsetOfMember));
 220   }
 221
 222   Type& operator()(Class& x)const
 223   {
 224     return *static_cast<Type*>(
 225       static_cast<void*>(
 226         static_cast<char*>(static_cast<void *>(&x))+OffsetOfMember));
 227   }
 228
 229   const Type& operator()(const reference_wrapper<const Class>& x,int=0)const
 230   {
 231     return operator()(x.get());
 232   }
 233
 234   Type& operator()(const reference_wrapper<Class>& x)const
 235   {
 236     return operator()(x.get());
 237   }
 238 };
 239
 240 } /* namespace multi_index::detail */
 241
 242 template<class Class,typename Type,std::size_t OffsetOfMember>
 243 struct member_offset:
 244   mpl::if_c<
 245     is_const<Type>::value,
 246     detail::const_member_offset_base<Class,Type,OffsetOfMember>,
 247     detail::non_const_member_offset_base<Class,Type,OffsetOfMember>
 248   >::type
 249 {
 250 };
 251
 252 /* BOOST_MULTI_INDEX_MEMBER resolves to member in the normal cases,
 253  * and to member_offset as a workaround in those defective compilers for
 254  * which BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS is defined.
 255  */
 256
 257 #if defined(BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS)
 258 #define BOOST_MULTI_INDEX_MEMBER(Class,Type,MemberName) \
 259 ::boost::multi_index::member_offset< Class,Type,offsetof(Class,MemberName) >
 260 #else
 261 #define BOOST_MULTI_INDEX_MEMBER(Class,Type,MemberName) \
 262 ::boost::multi_index::member< Class,Type,&Class::MemberName >
 263 #endif
 264
 265 } /* namespace multi_index */
 266
 267 } /* namespace boost */
 268
 269 #endif