ceph/src/boost/libs/dll/include/boost/dll/detail/import_mangled_helpers.hpp

   1 // Copyright 2015-2016 Klemens D. Morgenstern
   2 //
   3 // Distributed under the Boost Software License, Version 1.0.
   4 // (See accompanying file LICENSE_1_0.txt
   5 // or copy at http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #ifndef BOOST_DLL_DETAIL_IMPORT_MANGLED_HELPERS_HPP_
   8 #define BOOST_DLL_DETAIL_IMPORT_MANGLED_HELPERS_HPP_
   9
  10
  11 #include <boost/type_traits/conditional.hpp>
  12 #include <boost/type_traits/is_same.hpp>
  13 #include <boost/type_traits/is_class.hpp>
  14 #include <boost/type_traits/is_function.hpp>
  15 #include <boost/type_traits/remove_cv.hpp>
  16
  17
  18 #ifdef BOOST_HAS_PRAGMA_ONCE
  19 # pragma once
  20 #endif
  21
  22 namespace boost { namespace dll { namespace experimental { namespace detail {
  23
  24 //the following could be done by fusion, though it's simple enough to just declare it here.
  25 template<class ...Args>
  26 struct sequence {};
  27
  28 template<class Value, class Seq> struct push_front;
  29 template<class Value, class ...Args>
  30 struct push_front<Value, sequence<Args...>>
  31 {
  32     typedef sequence<Value, Args...> type;
  33 };
  34
  35 template<class Lhs, class Rhs>
  36 struct unqalified_is_same :
  37         boost::is_same<
  38             typename boost::remove_cv<Lhs>::type,
  39             typename boost::remove_cv<Rhs>::type
  40         >
  41 {
  42 };
  43
  44 /* ********************************** function sequence type traits ******************************/
  45
  46 //determine if it's a sequence of functions.
  47 template<class T> struct is_function_seq;
  48
  49 //type-trait for function overloads
  50 template<class Class, class...Args> struct is_function_seq<sequence<Class, Args...>>
  51             : boost::conditional<
  52                 boost::is_function<Class>::value,
  53                 is_function_seq<sequence<Args...>>,
  54                 boost::false_type>::type
  55 {};
  56
  57 template<class Class>
  58 struct is_function_seq<sequence<Class>> : boost::is_function<Class>
  59 {
  60 };
  61
  62 template<>
  63 struct is_function_seq<sequence<>> : boost::false_type
  64 {
  65 };
  66
  67 /* ********************************* Function Tuple ***************************  */
  68
  69 //a tuple of plain functions.
  70 template <class ...Ts>
  71 struct function_tuple;
  72
  73 template <class Return, class...Args, class T2, class ...Ts>
  74 struct function_tuple<Return(Args...), T2, Ts...> : function_tuple<T2, Ts...>
  75 {
  76     constexpr function_tuple(Return(* t)(Args...), T2* t2, Ts* ... ts) : function_tuple<T2, Ts...>(t2, ts...), _f(t) {};
  77     Return(*_f)(Args...);
  78
  79     Return operator()(Args...args)
  80     {
  81         return (*_f)(static_cast<Args>(args)...);
  82     }
  83     using function_tuple<T2, Ts...>::operator();
  84
  85 };
  86
  87 template <class Return, class...Args>
  88 struct function_tuple<Return(Args...)>
  89 {
  90     constexpr function_tuple(Return(* t)(Args...)) : _f(t) {};
  91     Return(*_f)(Args...);
  92
  93     Return operator()(Args...args)
  94     {
  95         return (*_f)(static_cast<Args>(args)...);
  96     }
  97 };
  98
  99
 100 /* ********************************** MemFn sequence type traits ******************************/
 101
 102 template<class Class, class Func>
 103 struct mem_fn_def
 104 {
 105     typedef Class class_type;
 106     typedef Func  func_type;
 107     typedef typename boost::dll::detail::get_mem_fn_type<Class, Func>::mem_fn mem_fn;
 108 };
 109
 110 template<class ...Args>
 111 struct make_mem_fn_seq;
 112
 113 // B: is T1 another version of T0?
 114 template<bool, class T0, class T1, class T2>
 115 struct make_mem_fn_seq_getter;
 116
 117 template<class T0, class T1, class T2>
 118 struct make_mem_fn_seq_getter<true, T0, T1, T2>
 119 {
 120     typedef mem_fn_def<T1, T2> type;
 121 };
 122
 123 template<class T0, class T1, class T2>
 124 struct make_mem_fn_seq_getter<false, T0, T1, T2>
 125 {
 126     typedef mem_fn_def<T0, T1> type;
 127 };
 128
 129 template<class Class, class Signature>
 130 struct make_mem_fn_seq<Class, Signature>
 131 {
 132     typedef mem_fn_def<Class, Signature> mem_fn;
 133     typedef sequence<mem_fn>   type;
 134 };
 135
 136 template<class Class>
 137 struct make_mem_fn_seq<Class>
 138 {
 139     typedef sequence<>   type;
 140 };
 141
 142 template<class T0, class T1, class T2, class ... Args>
 143 struct make_mem_fn_seq<T0, T1, T2, Args...>
 144 {
 145     /* Since we might have ovls, it might be :
 146      * Class, void(int), void(int, int) //--> just us class for both
 147      * Class, const Class, void(int)//--> ovl class.
 148      *
 149      */
 150     static_assert(boost::is_object<T0>::value, "");
 151     typedef typename make_mem_fn_seq_getter<
 152            unqalified_is_same<T0, T1>::value, T0, T1, T2>::type mem_fn_type;
 153
 154     typedef typename boost::conditional<
 155         unqalified_is_same<T0, T1>::value,
 156         make_mem_fn_seq<T1, Args...>,
 157         make_mem_fn_seq<T0, T2, Args...>> ::type next;
 158
 159     typedef typename push_front<mem_fn_type, typename next::type>::type type;
 160 };
 161
 162
 163
 164
 165 /* Ok, this needs to be documented, so here's some pseudo-code:
 166  *
 167  * @code
 168  *
 169  * bool unqalified_is_same(lhs, rhs)
 170  * {
 171  *    return remove_cv(lhs) == remove_cv(rhs);
 172  * }
 173  *
 174  * mem_fn make_mem_fn_seq_getter(b, cl, T2, T3)
 175  * {
 176  *    if (b) //b means, that T2 is another version of cl, i.e. qualified
 177  *       return get_mem_fn_type(T2, T3);
 178  *    else //means that T2 is a function.
 179  *       return get_mem_fn_type(cl, T2);
 180  * }
 181  *
 182  * sequence make_mem_fn_seq(type cl, type T2, type T3, types...)
 183  * {
 184  *     mem_fn = make_mem_fn_seq_getter(
 185  *               unqalified_is_same(cl, T2), cl, T2, T3);
 186  *
 187  *     next = unqalified_is_same(cl, T2) ?
 188  *              make_mem_fn_seq(T2, types...) //because: T2 is another version of cl, hence i use this. T3 was already consumed.
 189  *              :
 190  *              make_mem_fn_seq(Class, T3, types...) //because: T2 was a function, hence it is consumed and class remains unchanged.
 191  *              ;
 192  *     return push_front(mem_fn, next) ;
 193  * };
 194  * @endcode
 195  */
 196
 197
 198
 199 template<class T, class U, class ...Args>
 200 struct is_mem_fn_seq_impl
 201 {
 202     typedef typename boost::conditional<
 203                  boost::is_function<U>::value || boost::dll::experimental::detail::unqalified_is_same<T, U>::value,
 204                  typename is_mem_fn_seq_impl<T, Args...>::type,
 205                  boost::false_type>::type type;
 206 };
 207
 208 template<class T, class U>
 209 struct is_mem_fn_seq_impl<T, U>
 210 {
 211     typedef typename boost::conditional<
 212                  boost::is_function<U>::value && boost::is_object<T>::value,
 213                  boost::true_type, boost::false_type>::type type;
 214 };
 215
 216 template<class T, class U, class Last>
 217 struct is_mem_fn_seq_impl<T, U, Last>
 218 {
 219     typedef typename boost::conditional<
 220                  (boost::is_function<U>::value || boost::dll::experimental::detail::unqalified_is_same<T, U>::value)
 221                  && boost::is_function<Last>::value,
 222                  boost::true_type, boost::false_type>::type type;
 223 };
 224
 225 template<class T> struct is_mem_fn_seq : boost::false_type {};
 226
 227 //If only two arguments are provided at all.
 228 template<class T, class U>
 229 struct is_mem_fn_seq<sequence<T, U>> : boost::conditional<
 230                  boost::is_object<T>::value && boost::is_function<U>::value,
 231                  boost::true_type, boost::false_type>::type
 232 {
 233 };
 234
 235
 236 template<class T, class Func, class ...Args>
 237 struct is_mem_fn_seq<sequence<T, Func, Args...>> :
 238         boost::conditional<
 239             boost::is_class<T>::value && boost::is_function<Func>::value,
 240             typename is_mem_fn_seq_impl<T, Args...>::type,
 241             boost::false_type>::type {};
 242
 243
 244 /* ********************************** mem fn sequence tuple ******************************/
 245
 246 /* A tuple of member functions
 247  * Unlike for plain functions a sequence here might contain classes as well as functions.
 248  */
 249 template <class ...Ts>
 250 struct mem_fn_tuple;
 251
 252 template <class Class, class Return, class...Args, class T2, class ...Ts>
 253 struct mem_fn_tuple<mem_fn_def<Class, Return(Args...)>, T2, Ts...> : mem_fn_tuple<T2, Ts...>
 254 {
 255     typedef typename boost::dll::detail::get_mem_fn_type<Class, Return(Args...)>::mem_fn mem_fn;
 256
 257     constexpr mem_fn_tuple(mem_fn f, typename T2::mem_fn t2, typename Ts::mem_fn ... ts)
 258                             : mem_fn_tuple<T2, Ts...>(t2, ts...), _f(f) {};
 259     mem_fn _f;
 260
 261     Return operator()(Class* const cl, Args...args)
 262     {
 263         return (cl->*_f)(static_cast<Args>(args)...);
 264     }
 265     using mem_fn_tuple<T2, Ts...>::operator();
 266
 267 };
 268
 269 template <class Class, class Return, class...Args>
 270 struct mem_fn_tuple<mem_fn_def<Class, Return(Args...)>>
 271 {
 272     typedef typename boost::dll::detail::get_mem_fn_type<Class, Return(Args...)>::mem_fn mem_fn;
 273
 274     constexpr mem_fn_tuple(mem_fn f) : _f(f) {};
 275     mem_fn _f;
 276
 277     Return operator()(Class * const cl, Args...args)
 278     {
 279         return (cl->*_f)(static_cast<Args>(args)...);
 280     }
 281 };
 282
 283 }}}}
 284 #endif /* BOOST_DLL_DETAIL_IMPORT_MANGLED_HELPERS_HPP_ */