1// (C) Copyright David Abrahams 2002.
2// (C) Copyright Jeremy Siek 2002.
3// (C) Copyright Thomas Witt 2002.
4// Distributed under the Boost Software License, Version 1.0. (See
5// accompanying file LICENSE_1_0.txt or copy at
6// http://www.boost.org/LICENSE_1_0.txt)
7#ifndef BOOST_INTEROPERABLE_23022003THW_HPP
8# define BOOST_INTEROPERABLE_23022003THW_HPP
9
10# include <boost/mpl/bool.hpp>
11# include <boost/mpl/or.hpp>
12
13# include <boost/type_traits/is_convertible.hpp>
14
15# include <boost/iterator/detail/config_def.hpp> // must appear last
16
17namespace boost {
18namespace iterators {
19
20 //
21 // Meta function that determines whether two
22 // iterator types are considered interoperable.
23 //
24 // Two iterator types A,B are considered interoperable if either
25 // A is convertible to B or vice versa.
26 // This interoperability definition is in sync with the
27 // standards requirements on constant/mutable container
28 // iterators (23.1 [lib.container.requirements]).
29 //
30 // For compilers that don't support is_convertible
31 // is_interoperable gives false positives. See comments
32 // on operator implementation for consequences.
33 //
34 template <typename A, typename B>
35 struct is_interoperable
36# ifdef BOOST_NO_STRICT_ITERATOR_INTEROPERABILITY
37 : mpl::true_
38# else
39 : mpl::or_<
40 is_convertible< A, B >
41 , is_convertible< B, A > >
42# endif
43 {
44 };
45
46} // namespace iterators
47
48using iterators::is_interoperable;
49
50} // namespace boost
51
52# include <boost/iterator/detail/config_undef.hpp>
53
54#endif // BOOST_INTEROPERABLE_23022003THW_HPP
55