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