boost/typeof/msvc/typeof_impl.hpp

   1
   2 // Copyright (C) 2005 Igor Chesnokov, mailto:ichesnokov@gmail.com (VC 6.5,VC 7.1 + counter code)
   3 // Copyright (C) 2005-2007 Peder Holt (VC 7.0 + framework)
   4 // Copyright (C) 2006 Steven Watanabe (VC 8.0)
   5
   6 // Use, modification and distribution is subject to the Boost Software
   7 // License, Version 1.0. (http://www.boost.org/LICENSE_1_0.txt)
   8
   9 #ifndef BOOST_TYPEOF_MSVC_TYPEOF_IMPL_HPP_INCLUDED
  10 # define BOOST_TYPEOF_MSVC_TYPEOF_IMPL_HPP_INCLUDED
  11
  12 # include <boost/config.hpp>
  13 # include <boost/detail/workaround.hpp>
  14 # include <boost/mpl/int.hpp>
  15 # include <boost/type_traits/is_function.hpp>
  16 # include <boost/utility/enable_if.hpp>
  17
  18 # if BOOST_WORKAROUND(BOOST_MSVC,>=1310)
  19 #  include <typeinfo>
  20 # endif
  21
  22 namespace boost
  23 {
  24     namespace type_of
  25     {
  26
  27         //Compile time constant code
  28 # if BOOST_WORKAROUND(BOOST_MSVC,>=1300) && defined(_MSC_EXTENSIONS)
  29         template<int N> struct the_counter;
  30
  31         template<typename T,int N = 5/*for similarity*/>
  32         struct encode_counter
  33         {
  34             __if_exists(the_counter<N + 256>)
  35             {
  36                 BOOST_STATIC_CONSTANT(unsigned,count=(encode_counter<T,N + 257>::count));
  37             }
  38             __if_not_exists(the_counter<N + 256>)
  39             {
  40                 __if_exists(the_counter<N + 64>)
  41                 {
  42                     BOOST_STATIC_CONSTANT(unsigned,count=(encode_counter<T,N + 65>::count));
  43                 }
  44                 __if_not_exists(the_counter<N + 64>)
  45                 {
  46                     __if_exists(the_counter<N + 16>)
  47                     {
  48                         BOOST_STATIC_CONSTANT(unsigned,count=(encode_counter<T,N + 17>::count));
  49                     }
  50                     __if_not_exists(the_counter<N + 16>)
  51                     {
  52                         __if_exists(the_counter<N + 4>)
  53                         {
  54                             BOOST_STATIC_CONSTANT(unsigned,count=(encode_counter<T,N + 5>::count));
  55                         }
  56                         __if_not_exists(the_counter<N + 4>)
  57                         {
  58                             __if_exists(the_counter<N>)
  59                             {
  60                                 BOOST_STATIC_CONSTANT(unsigned,count=(encode_counter<T,N + 1>::count));
  61                             }
  62                             __if_not_exists(the_counter<N>)
  63                             {
  64                                 BOOST_STATIC_CONSTANT(unsigned,count=N);
  65                                 typedef the_counter<N> type;
  66                             }
  67                         }
  68                     }
  69                 }
  70             }
  71         };
  72
  73 # define BOOST_TYPEOF_INDEX(T) (encode_counter<T>::count)
  74 # define BOOST_TYPEOF_NEXT_INDEX(next)
  75 # else
  76         template<int N> struct encode_counter : encode_counter<N - 1> {};
  77         template<> struct encode_counter<0> {};
  78
  79         //Need to default to a larger value than 4, as due to MSVC's ETI errors. (sizeof(int)==4)
  80         char (*encode_index(...))[5];
  81
  82 # define BOOST_TYPEOF_INDEX(T) (sizeof(*boost::type_of::encode_index((boost::type_of::encode_counter<1005>*)0)))
  83 # define BOOST_TYPEOF_NEXT_INDEX(next) friend char (*encode_index(encode_counter<next>*))[next];
  84 # endif
  85
  86         //Typeof code
  87
  88 # if BOOST_WORKAROUND(BOOST_MSVC,==1300)
  89         template<typename ID>
  90         struct msvc_extract_type
  91         {
  92             template<bool>
  93             struct id2type_impl;
  94
  95             typedef id2type_impl<true> id2type;
  96         };
  97
  98         template<typename T, typename ID>
  99         struct msvc_register_type : msvc_extract_type<ID>
 100         {
 101             template<>
 102             struct id2type_impl<true>  //VC7.0 specific bugfeature
 103             {
 104                 typedef T type;
 105             };
 106         };
 107 #elif BOOST_WORKAROUND(BOOST_MSVC,>=1400)
 108         struct msvc_extract_type_default_param {};
 109
 110         template<typename ID, typename T = msvc_extract_type_default_param>
 111         struct msvc_extract_type;
 112
 113         template<typename ID>
 114         struct msvc_extract_type<ID, msvc_extract_type_default_param> {
 115             template<bool>
 116             struct id2type_impl;
 117
 118             typedef id2type_impl<true> id2type;
 119         };
 120
 121         template<typename ID, typename T>
 122         struct msvc_extract_type : msvc_extract_type<ID,msvc_extract_type_default_param>
 123         {
 124             template<>
 125             struct id2type_impl<true>  //VC8.0 specific bugfeature
 126             {
 127                 typedef T type;
 128             };
 129             template<bool>
 130             struct id2type_impl;
 131
 132             typedef id2type_impl<true> id2type;
 133         };
 134
 135         template<typename T, typename ID>
 136         struct msvc_register_type : msvc_extract_type<ID, T>
 137         {
 138         };
 139 # else
 140         template<typename ID>
 141         struct msvc_extract_type
 142         {
 143             struct id2type;
 144         };
 145
 146         template<typename T, typename ID>
 147         struct msvc_register_type : msvc_extract_type<ID>
 148         {
 149             typedef msvc_extract_type<ID> base_type;
 150             struct base_type::id2type // This uses nice VC6.5 and VC7.1 bugfeature
 151             {
 152                 typedef T type;
 153             };
 154         };
 155 # endif
 156 // EAN: preprocess this block out on advice of Peder Holt
 157 // to eliminate errors in type_traits/common_type.hpp
 158 # if 0 //BOOST_WORKAROUND(BOOST_MSVC,==1310)
 159         template<const std::type_info& ref_type_info>
 160         struct msvc_typeid_wrapper {
 161             typedef typename msvc_extract_type<msvc_typeid_wrapper>::id2type id2type;
 162             typedef typename id2type::type wrapped_type;
 163             typedef typename wrapped_type::type type;
 164         };
 165         //This class is used for registering the type T. encode_type<T> is mapped against typeid(encode_type<T>).
 166         //msvc_typeid_wrapper<typeid(encode_type<T>)> will now have a type typedef that equals encode_type<T>.
 167         template<typename T>
 168         struct encode_type
 169         {
 170             typedef encode_type<T> input_type;
 171             //Invoke registration of encode_type<T>. typeid(encode_type<T>) is now mapped to encode_type<T>. Do not use registered_type for anything.
 172             //The reason for registering encode_type<T> rather than T, is that VC handles typeid(function reference) poorly. By adding another
 173             //level of indirection, we solve this problem.
 174             typedef typename msvc_register_type<input_type,msvc_typeid_wrapper<typeid(input_type)> >::id2type registered_type;
 175             typedef T type;
 176         };
 177
 178         template<typename T> typename disable_if<
 179             typename is_function<T>::type,
 180             typename encode_type<T>::input_type>::type encode_start(T const&);
 181
 182         template<typename T> typename enable_if<
 183             typename is_function<T>::type,
 184             typename encode_type<T>::input_type>::type encode_start(T&);
 185
 186         template<typename Organizer, typename T>
 187         msvc_register_type<T,Organizer> typeof_register_type(const T&);
 188
 189
 190 # define BOOST_TYPEOF(expr) \
 191     boost::type_of::msvc_typeid_wrapper<typeid(boost::type_of::encode_start(expr))>::type
 192
 193 # define BOOST_TYPEOF_TPL(expr) typename BOOST_TYPEOF(expr)
 194
 195 # define BOOST_TYPEOF_NESTED_TYPEDEF_TPL(name,expr) \
 196 struct name {\
 197     enum {_typeof_register_value=sizeof(typeid(boost::type_of::typeof_register_type<name>(expr)))};\
 198     typedef typename boost::type_of::msvc_extract_type<name>::id2type id2type;\
 199     typedef typename id2type::type type;\
 200 };
 201
 202 # define BOOST_TYPEOF_NESTED_TYPEDEF(name,expr) \
 203 struct name {\
 204     enum {_typeof_register_value=sizeof(typeid(boost::type_of::typeof_register_type<name>(expr)))};\
 205     typedef boost::type_of::msvc_extract_type<name>::id2type id2type;\
 206     typedef id2type::type type;\
 207 };
 208
 209 # else
 210         template<int ID>
 211         struct msvc_typeid_wrapper {
 212             typedef typename msvc_extract_type<mpl::int_<ID> >::id2type id2type;
 213             typedef typename id2type::type type;
 214         };
 215         //Workaround for ETI-bug for VC6 and VC7
 216         template<>
 217         struct msvc_typeid_wrapper<1> {
 218             typedef msvc_typeid_wrapper<1> type;
 219         };
 220         //Workaround for ETI-bug for VC7.1
 221         template<>
 222         struct msvc_typeid_wrapper<4> {
 223             typedef msvc_typeid_wrapper<4> type;
 224         };
 225
 226         //Tie it all together
 227         template<typename T>
 228         struct encode_type
 229         {
 230             //Get the next available compile time constants index
 231             BOOST_STATIC_CONSTANT(unsigned,value=BOOST_TYPEOF_INDEX(T));
 232             //Instantiate the template
 233             typedef typename msvc_register_type<T,mpl::int_<value> >::id2type type;
 234             //Set the next compile time constants index
 235             BOOST_STATIC_CONSTANT(unsigned,next=value+1);
 236             //Increment the compile time constant (only needed when extensions are not active
 237             BOOST_TYPEOF_NEXT_INDEX(next);
 238         };
 239
 240         template<class T>
 241         struct sizer
 242         {
 243             typedef char(*type)[encode_type<T>::value];
 244         };
 245 # if BOOST_WORKAROUND(BOOST_MSVC,>=1310)
 246         template<typename T> typename disable_if<
 247             typename is_function<T>::type,
 248             typename sizer<T>::type>::type encode_start(T const&);
 249
 250         template<typename T> typename enable_if<
 251             typename is_function<T>::type,
 252             typename sizer<T>::type>::type encode_start(T&);
 253 # else
 254         template<typename T>
 255             typename sizer<T>::type encode_start(T const&);
 256 # endif
 257         template<typename Organizer, typename T>
 258         msvc_register_type<T,Organizer> typeof_register_type(const T&,Organizer* =0);
 259
 260 # define BOOST_TYPEOF(expr) \
 261     boost::type_of::msvc_typeid_wrapper<sizeof(*boost::type_of::encode_start(expr))>::type
 262
 263 # define BOOST_TYPEOF_TPL(expr) typename BOOST_TYPEOF(expr)
 264
 265 # define BOOST_TYPEOF_NESTED_TYPEDEF_TPL(name,expr) \
 266     struct name {\
 267         BOOST_STATIC_CONSTANT(int,_typeof_register_value=sizeof(boost::type_of::typeof_register_type<name>(expr)));\
 268         typedef typename boost::type_of::msvc_extract_type<name>::id2type id2type;\
 269         typedef typename id2type::type type;\
 270     };
 271
 272 # define BOOST_TYPEOF_NESTED_TYPEDEF(name,expr) \
 273     struct name {\
 274         BOOST_STATIC_CONSTANT(int,_typeof_register_value=sizeof(boost::type_of::typeof_register_type<name>(expr)));\
 275         typedef boost::type_of::msvc_extract_type<name>::id2type id2type;\
 276         typedef id2type::type type;\
 277     };
 278
 279 #endif
 280     }
 281 }
 282
 283 #endif//BOOST_TYPEOF_MSVC_TYPEOF_IMPL_HPP_INCLUDED