ceph/src/boost/libs/python/include/boost/python/detail/referent_storage.hpp

   1 // Copyright David Abrahams 2002.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5 #ifndef REFERENT_STORAGE_DWA200278_HPP
   6 # define REFERENT_STORAGE_DWA200278_HPP
   7 # include <boost/mpl/if.hpp>
   8 # include <cstddef>
   9
  10 namespace boost { namespace python { namespace detail {
  11
  12 struct alignment_dummy;
  13 typedef void (*function_ptr)();
  14 typedef int (alignment_dummy::*member_ptr);
  15 typedef int (alignment_dummy::*member_function_ptr)();
  16
  17 # define BOOST_PYTHON_ALIGNER(T, n)                     \
  18         typename mpl::if_c<                             \
  19            sizeof(T) <= size, T, char>::type t##n
  20
  21 // Storage for size bytes, aligned to all fundamental types no larger than size
  22 template <std::size_t size>
  23 union aligned_storage
  24 {
  25     BOOST_PYTHON_ALIGNER(char, 0);
  26     BOOST_PYTHON_ALIGNER(short, 1);
  27     BOOST_PYTHON_ALIGNER(int, 2);
  28     BOOST_PYTHON_ALIGNER(long, 3);
  29     BOOST_PYTHON_ALIGNER(float, 4);
  30     BOOST_PYTHON_ALIGNER(double, 5);
  31     BOOST_PYTHON_ALIGNER(long double, 6);
  32     BOOST_PYTHON_ALIGNER(void*, 7);
  33     BOOST_PYTHON_ALIGNER(function_ptr, 8);
  34     BOOST_PYTHON_ALIGNER(member_ptr, 9);
  35     BOOST_PYTHON_ALIGNER(member_function_ptr, 10);
  36     char bytes[size];
  37 };
  38
  39 # undef BOOST_PYTHON_ALIGNER
  40
  41   // Compute the size of T's referent. We wouldn't need this at all,
  42   // but sizeof() is broken in CodeWarriors <= 8.0
  43   template <class T> struct referent_size;
  44
  45
  46   template <class T>
  47   struct referent_size<T&>
  48   {
  49       BOOST_STATIC_CONSTANT(
  50           std::size_t, value = sizeof(T));
  51   };
  52
  53
  54 // A metafunction returning a POD type which can store U, where T ==
  55 // U&. If T is not a reference type, returns a POD which can store T.
  56 template <class T>
  57 struct referent_storage
  58 {
  59     typedef aligned_storage<
  60         ::boost::python::detail::referent_size<T>::value
  61     > type;
  62 };
  63
  64 }}} // namespace boost::python::detail
  65
  66 #endif // REFERENT_STORAGE_DWA200278_HPP