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(BOOST_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
77