blob: 6f3c872a27ba7d7d484e1c8c3db53a5f5ff56182 [file] [log] [blame]
// (C) Copyright David Abrahams 2002.
// (C) Copyright Jeremy Siek 2002.
// (C) Copyright Thomas Witt 2002.
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_INTEROPERABLE_23022003THW_HPP
# define BOOST_INTEROPERABLE_23022003THW_HPP
# include <boost/mpl/bool.hpp>
# include <boost/mpl/or.hpp>
# include <boost/type_traits/is_convertible.hpp>
# include <boost/iterator/detail/config_def.hpp> // must appear last
namespace boost {
namespace iterators {
//
// Meta function that determines whether two
// iterator types are considered interoperable.
//
// Two iterator types A,B are considered interoperable if either
// A is convertible to B or vice versa.
// This interoperability definition is in sync with the
// standards requirements on constant/mutable container
// iterators (23.1 [lib.container.requirements]).
//
// For compilers that don't support is_convertible
// is_interoperable gives false positives. See comments
// on operator implementation for consequences.
//
template <typename A, typename B>
struct is_interoperable
# ifdef BOOST_NO_STRICT_ITERATOR_INTEROPERABILITY
: mpl::true_
# else
: mpl::or_<
is_convertible< A, B >
, is_convertible< B, A > >
# endif
{
};
} // namespace iterators
using iterators::is_interoperable;
} // namespace boost
# include <boost/iterator/detail/config_undef.hpp>
#endif // BOOST_INTEROPERABLE_23022003THW_HPP