boost/fusion/functional/invocation/invoke.hpp

   1 /*=============================================================================
   2     Copyright (c) 2005-2006 Joao Abecasis
   3     Copyright (c) 2006-2007 Tobias Schwinger
   4
   5     Use modification and distribution are subject to the Boost Software
   6     License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   7     http://www.boost.org/LICENSE_1_0.txt).
   8 ==============================================================================*/
   9
  10 #if !defined(BOOST_FUSION_FUNCTIONAL_INVOCATION_INVOKE_HPP_INCLUDED)
  11 #if !defined(BOOST_PP_IS_ITERATING)
  12
  13 #include <boost/preprocessor/cat.hpp>
  14 #include <boost/preprocessor/iteration/iterate.hpp>
  15 #include <boost/preprocessor/arithmetic/dec.hpp>
  16 #include <boost/preprocessor/repetition/repeat_from_to.hpp>
  17 #include <boost/preprocessor/repetition/enum.hpp>
  18 #include <boost/preprocessor/repetition/enum_shifted.hpp>
  19 #include <boost/preprocessor/repetition/enum_params.hpp>
  20 #include <boost/preprocessor/repetition/enum_shifted_params.hpp>
  21
  22 #include <boost/mpl/if.hpp>
  23 #include <boost/mpl/eval_if.hpp>
  24 #include <boost/mpl/or.hpp>
  25 #include <boost/mpl/front.hpp>
  26 #include <boost/mpl/identity.hpp>
  27
  28 #include <boost/type_traits/add_const.hpp>
  29 #include <boost/type_traits/remove_cv.hpp>
  30 #include <boost/type_traits/add_reference.hpp>
  31 #include <boost/type_traits/remove_reference.hpp>
  32 #include <boost/type_traits/is_convertible.hpp>
  33
  34 #include <boost/function_types/is_function.hpp>
  35 #include <boost/function_types/is_callable_builtin.hpp>
  36 #include <boost/function_types/is_member_pointer.hpp>
  37 #include <boost/function_types/is_member_function_pointer.hpp>
  38 #include <boost/function_types/result_type.hpp>
  39 #include <boost/function_types/parameter_types.hpp>
  40
  41 #include <boost/utility/result_of.hpp>
  42
  43 #include <boost/fusion/support/category_of.hpp>
  44 #include <boost/fusion/sequence/intrinsic/at.hpp>
  45 #include <boost/fusion/sequence/intrinsic/size.hpp>
  46 #include <boost/fusion/sequence/intrinsic/front.hpp>
  47 #include <boost/fusion/sequence/intrinsic/begin.hpp>
  48 #include <boost/fusion/iterator/next.hpp>
  49 #include <boost/fusion/iterator/deref.hpp>
  50 #include <boost/fusion/functional/invocation/limits.hpp>
  51 #include <boost/fusion/functional/invocation/detail/that_ptr.hpp>
  52
  53 namespace boost { namespace fusion
  54 {
  55     namespace result_of
  56     {
  57         template <typename Function, class Sequence> struct invoke;
  58     }
  59
  60     template <typename Function, class Sequence>
  61     inline typename result_of::invoke<Function, Sequence>::type
  62     invoke(Function, Sequence &);
  63
  64     template <typename Function, class Sequence>
  65     inline typename result_of::invoke<Function, Sequence const>::type
  66     invoke(Function, Sequence const &);
  67
  68     //----- ---- --- -- - -  -   -
  69
  70     namespace detail
  71     {
  72         namespace ft = function_types;
  73
  74         template<
  75             typename Function, class Sequence,
  76             int N = result_of::size<Sequence>::value,
  77             bool CBI = ft::is_callable_builtin<Function>::value,
  78             bool RandomAccess = traits::is_random_access<Sequence>::value
  79             >
  80         struct invoke_impl;
  81
  82         template <class Sequence, int N>
  83         struct invoke_param_types;
  84
  85         template <typename T, class Sequence>
  86         struct invoke_data_member;
  87
  88         template <typename Function, class Sequence, int N, bool RandomAccess>
  89         struct invoke_mem_fn;
  90
  91         #define  BOOST_PP_FILENAME_1 <boost/fusion/functional/invocation/invoke.hpp>
  92         #define  BOOST_PP_ITERATION_LIMITS (0, BOOST_FUSION_INVOKE_MAX_ARITY)
  93         #include BOOST_PP_ITERATE()
  94
  95         template <typename F, class Sequence, int N, bool RandomAccess>
  96         struct invoke_nonmember_builtin
  97         // use same implementation as for function objects but...
  98             : invoke_impl< // ...work around boost::result_of bugs
  99                 typename mpl::eval_if< ft::is_function<F>,
 100                     boost::add_reference<F>, boost::remove_cv<F> >::type,
 101                 Sequence, N, false, RandomAccess >
 102         { };
 103
 104         template <typename Function, class Sequence, int N, bool RandomAccess>
 105         struct invoke_impl<Function,Sequence,N,true,RandomAccess>
 106             : mpl::if_< ft::is_member_function_pointer<Function>,
 107                 invoke_mem_fn<Function,Sequence,N,RandomAccess>,
 108                 invoke_nonmember_builtin<Function,Sequence,N,RandomAccess>
 109             >::type
 110         { };
 111
 112         template <typename Function, class Sequence, bool RandomAccess>
 113         struct invoke_impl<Function,Sequence,1,true,RandomAccess>
 114             : mpl::eval_if< ft::is_member_pointer<Function>,
 115                 mpl::if_< ft::is_member_function_pointer<Function>,
 116                     invoke_mem_fn<Function,Sequence,1,RandomAccess>,
 117                     invoke_data_member<Function, Sequence> >,
 118                 mpl::identity< invoke_nonmember_builtin<
 119                     Function,Sequence,1,RandomAccess> >
 120             >::type
 121         { };
 122
 123         template <typename T, class C, class Sequence>
 124         struct invoke_data_member< T C::*, Sequence >
 125         {
 126         private:
 127
 128             typedef typename result_of::front<Sequence>::type that;
 129
 130             typedef mpl::or_< boost::is_convertible<that,C*>,
 131                               boost::is_convertible<that,C&>,
 132                               non_const_pointee<that> > non_const_cond;
 133
 134             typedef typename mpl::eval_if< non_const_cond,
 135                 mpl::identity<C>, add_const<C> >::type qualified_class;
 136
 137             typedef typename mpl::eval_if< non_const_cond,
 138                 mpl::identity<T>, add_const<T> >::type qualified_type;
 139
 140         public:
 141
 142             typedef typename boost::add_reference<qualified_type>::type
 143                 result_type;
 144
 145             static inline result_type call(T C::* f, Sequence & s)
 146             {
 147                 typename result_of::front<Sequence>::type c = fusion::front(s);
 148                 return that_ptr<qualified_class>::get(c)->*f;
 149             }
 150         };
 151     }
 152
 153     namespace result_of
 154     {
 155         template <typename Function, class Sequence> struct invoke
 156         {
 157             typedef typename detail::invoke_impl<
 158                 typename boost::remove_reference<Function>::type, Sequence
 159               >::result_type type;
 160         };
 161     }
 162
 163     template <typename Function, class Sequence>
 164     inline typename result_of::invoke<Function,Sequence>::type
 165     invoke(Function f, Sequence & s)
 166     {
 167         return detail::invoke_impl<
 168                 typename boost::remove_reference<Function>::type,Sequence
 169             >::call(f,s);
 170     }
 171
 172     template <typename Function, class Sequence>
 173     inline typename result_of::invoke<Function,Sequence const>::type
 174     invoke(Function f, Sequence const & s)
 175     {
 176         return detail::invoke_impl<
 177                 typename boost::remove_reference<Function>::type,Sequence const
 178             >::call(f,s);
 179     }
 180
 181 }}
 182
 183 #define BOOST_FUSION_FUNCTIONAL_INVOCATION_INVOKE_HPP_INCLUDED
 184 #else // defined(BOOST_PP_IS_ITERATING)
 185 ///////////////////////////////////////////////////////////////////////////////
 186 //
 187 //  Preprocessor vertical repetition code
 188 //
 189 ///////////////////////////////////////////////////////////////////////////////
 190 #define N BOOST_PP_ITERATION()
 191
 192         template <typename Function, class Sequence>
 193         struct invoke_impl<Function,Sequence,N,false,true>
 194         {
 195         public:
 196
 197             typedef typename boost::result_of<
 198 #define M(z,j,data) typename result_of::at_c<Sequence,j>::type
 199                     Function(BOOST_PP_ENUM(N,M,~)) >::type result_type;
 200 #undef M
 201
 202 #if N > 0
 203
 204             template <typename F>
 205             static inline result_type
 206             call(F & f, Sequence & s)
 207             {
 208 #define M(z,j,data) fusion::at_c<j>(s)
 209                 return f( BOOST_PP_ENUM(N,M,~) );
 210             }
 211
 212 #else
 213             template <typename F>
 214             static inline result_type
 215             call(F & f, Sequence & /*s*/)
 216             {
 217                 return f();
 218             }
 219
 220 #endif
 221
 222         };
 223
 224
 225 #if N > 0
 226         template <typename Function, class Sequence>
 227         struct invoke_mem_fn<Function,Sequence,N,true>
 228         {
 229         public:
 230
 231             typedef typename ft::result_type<Function>::type result_type;
 232
 233             template <typename F>
 234             static inline result_type
 235             call(F & f, Sequence & s)
 236             {
 237                 return (that_ptr<typename mpl::front<
 238                                 ft::parameter_types<Function> >::type
 239                     >::get(fusion::at_c<0>(s))->*f)(BOOST_PP_ENUM_SHIFTED(N,M,~));
 240             }
 241         };
 242 #endif
 243
 244 #undef M
 245
 246 #define M(z,j,data)                                                             \
 247             typename seq::I##j i##j =                                          \
 248                 fusion::next(BOOST_PP_CAT(i,BOOST_PP_DEC(j)));
 249
 250         template <typename Function, class Sequence>
 251         struct invoke_impl<Function,Sequence,N,false,false>
 252         {
 253         private:
 254             typedef invoke_param_types<Sequence,N> seq;
 255         public:
 256
 257             typedef typename boost::result_of<
 258                 Function(BOOST_PP_ENUM_PARAMS(N,typename seq::T))
 259                 >::type result_type;
 260
 261 #if N > 0
 262
 263             template <typename F>
 264             static inline result_type
 265             call(F & f, Sequence & s)
 266             {
 267                 typename seq::I0 i0 = fusion::begin(s);
 268                 BOOST_PP_REPEAT_FROM_TO(1,N,M,~)
 269                 return f( BOOST_PP_ENUM_PARAMS(N,*i) );
 270             }
 271
 272 #else
 273
 274             template <typename F>
 275             static inline result_type
 276             call(F & f, Sequence & /*s*/)
 277             {
 278                 return f();
 279             }
 280
 281 #endif
 282
 283         };
 284
 285 #if N > 0
 286         template <typename Function, class Sequence>
 287         struct invoke_mem_fn<Function,Sequence,N,false>
 288         {
 289         private:
 290             typedef invoke_param_types<Sequence,N> seq;
 291         public:
 292
 293             typedef typename ft::result_type<Function>::type result_type;
 294
 295             template <typename F>
 296             static inline result_type
 297             call(F & f, Sequence & s)
 298             {
 299                 typename seq::I0 i0 = fusion::begin(s);
 300                 BOOST_PP_REPEAT_FROM_TO(1,N,M,~)
 301
 302                 return (that_ptr< typename mpl::front<
 303                                       ft::parameter_types<Function> >::type
 304                     >::get(*i0)->*f)(BOOST_PP_ENUM_SHIFTED_PARAMS(N,*i));
 305             }
 306         };
 307 #endif
 308
 309 #undef M
 310
 311         template <class Sequence> struct invoke_param_types<Sequence,N>
 312         {
 313 #if N > 0
 314             typedef typename result_of::begin<Sequence>::type I0;
 315             typedef typename result_of::deref<I0>::type T0;
 316
 317 #define M(z,i,data)                                                             \
 318             typedef typename result_of::next<                                  \
 319                 BOOST_PP_CAT(I,BOOST_PP_DEC(i))>::type I##i;                   \
 320             typedef typename result_of::deref<I##i>::type T##i;
 321
 322             BOOST_PP_REPEAT_FROM_TO(1,N,M,~)
 323 #undef M
 324 #endif
 325         };
 326
 327
 328 #undef N
 329 #endif // defined(BOOST_PP_IS_ITERATING)
 330 #endif
 331