ceph/src/boost/boost/pointee.hpp

   1 #ifndef POINTEE_DWA200415_HPP
   2 # define POINTEE_DWA200415_HPP
   3
   4 //
   5 // Copyright David Abrahams 2004. Use, modification and distribution is
   6 // subject to the Boost Software License, Version 1.0. (See accompanying
   7 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8 //
   9 // typename pointee<P>::type provides the pointee type of P.
  10 //
  11 // For example, it is T for T* and X for shared_ptr<X>.
  12 //
  13 // http://www.boost.org/libs/iterator/doc/pointee.html
  14 //
  15
  16 # include <boost/detail/is_incrementable.hpp>
  17 # include <boost/iterator/iterator_traits.hpp>
  18 # include <boost/type_traits/add_const.hpp>
  19 # include <boost/type_traits/remove_cv.hpp>
  20 # include <boost/mpl/if.hpp>
  21 # include <boost/mpl/eval_if.hpp>
  22
  23 #include <iterator>
  24
  25 namespace boost {
  26
  27 namespace detail
  28 {
  29   template <class P>
  30   struct smart_ptr_pointee
  31   {
  32       typedef typename P::element_type type;
  33   };
  34
  35   template <class Iterator>
  36   struct iterator_pointee
  37   {
  38       typedef typename std::iterator_traits<Iterator>::value_type value_type;
  39
  40       struct impl
  41       {
  42           template <class T>
  43           static char test(T const&);
  44
  45           static char (& test(value_type&) )[2];
  46
  47           static Iterator& x;
  48       };
  49
  50       BOOST_STATIC_CONSTANT(bool, is_constant = sizeof(impl::test(*impl::x)) == 1);
  51
  52       typedef typename mpl::if_c<
  53 #  if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
  54           ::boost::detail::iterator_pointee<Iterator>::is_constant
  55 #  else
  56           is_constant
  57 #  endif
  58         , typename add_const<value_type>::type
  59         , value_type
  60       >::type type;
  61   };
  62 }
  63
  64 template <class P>
  65 struct pointee
  66   : mpl::eval_if<
  67         detail::is_incrementable<P>
  68       , detail::iterator_pointee<P>
  69       , detail::smart_ptr_pointee<P>
  70     >
  71 {
  72 };
  73
  74 } // namespace boost
  75
  76 #endif // POINTEE_DWA200415_HPP