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 | namespace boost { |
24 | |
25 | namespace detail |
26 | { |
27 | template <class P> |
28 | struct smart_ptr_pointee |
29 | { |
30 | typedef typename P::element_type type; |
31 | }; |
32 | |
33 | template <class Iterator> |
34 | struct iterator_pointee |
35 | { |
36 | typedef typename iterator_traits<Iterator>::value_type value_type; |
37 | |
38 | struct impl |
39 | { |
40 | template <class T> |
41 | static char test(T const&); |
42 | |
43 | static char (& test(value_type&) )[2]; |
44 | |
45 | static Iterator& x; |
46 | }; |
47 | |
48 | BOOST_STATIC_CONSTANT(bool, is_constant = sizeof(impl::test(*impl::x)) == 1); |
49 | |
50 | typedef typename mpl::if_c< |
51 | # if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551)) |
52 | ::boost::detail::iterator_pointee<Iterator>::is_constant |
53 | # else |
54 | is_constant |
55 | # endif |
56 | , typename add_const<value_type>::type |
57 | , value_type |
58 | >::type type; |
59 | }; |
60 | } |
61 | |
62 | template <class P> |
63 | struct pointee |
64 | : mpl::eval_if< |
65 | detail::is_incrementable<P> |
66 | , detail::iterator_pointee<P> |
67 | , detail::smart_ptr_pointee<P> |
68 | > |
69 | { |
70 | }; |
71 | |
72 | } // namespace boost |
73 | |
74 | #endif // POINTEE_DWA200415_HPP |
75 |