source: NonGTP/Boost/boost/iterator/interoperable.hpp @ 857

Revision 857, 1.5 KB checked in by igarcia, 19 years ago (diff)
Line 
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
18{
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 boost
47
48# include <boost/iterator/detail/config_undef.hpp>
49
50#endif // BOOST_INTEROPERABLE_23022003THW_HPP
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