| 1 | // Copyright 2004 The Trustees of Indiana University. |
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| 2 | |
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| 3 | // Use, modification and distribution is subject to the Boost Software |
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| 4 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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| 5 | // http://www.boost.org/LICENSE_1_0.txt) |
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| 6 | |
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| 7 | // Authors: Douglas Gregor |
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| 8 | // Andrew Lumsdaine |
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| 9 | |
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| 10 | // |
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| 11 | // This file contains helps that enable concept-based overloading |
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| 12 | // within the Boost Graph Library. |
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| 13 | // |
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| 14 | #ifndef BOOST_GRAPH_OVERLOADING_HPP |
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| 15 | #define BOOST_GRAPH_OVERLOADING_HPP |
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| 16 | |
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| 17 | #include <boost/type_traits/is_base_and_derived.hpp> |
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| 18 | #include <boost/utility/enable_if.hpp> |
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| 19 | |
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| 20 | namespace boost { namespace graph { namespace detail { |
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| 21 | |
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| 22 | struct no_parameter {}; |
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| 23 | |
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| 24 | } } } // end namespace boost::graph::detail |
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| 25 | |
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| 26 | #ifndef BOOST_NO_SFINAE |
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| 27 | |
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| 28 | #define BOOST_GRAPH_ENABLE_IF_MODELS(Graph, Tag, Type) \ |
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| 29 | typename enable_if_c<(is_base_and_derived< \ |
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| 30 | Tag, \ |
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| 31 | typename graph_traits<Graph>::traversal_category>::value), \ |
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| 32 | Type>::type |
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| 33 | |
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| 34 | #define BOOST_GRAPH_ENABLE_IF_MODELS_PARM(Graph, Tag) \ |
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| 35 | , BOOST_GRAPH_ENABLE_IF_MODELS(Graph, Tag, \ |
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| 36 | ::boost::graph::detail::no_parameter) \ |
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| 37 | = ::boost::graph::detail::no_parameter() |
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| 38 | |
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| 39 | #else |
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| 40 | |
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| 41 | #define BOOST_GRAPH_ENABLE_IF_MODELS(Graph, Tag, Type) Type |
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| 42 | #define BOOST_GRAPH_ENABLE_IF_MODELS_PARM(Graph, Tag) |
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| 43 | |
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| 44 | #endif // no SFINAE support |
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| 45 | |
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| 46 | #endif // BOOST_GRAPH_OVERLOADING_HPP |
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| 47 | |
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