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