//======================================================================= // Copyright 1997, 1998, 1999, 2000 University of Notre Dame. // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek // // 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_GRAPH_NAMED_FUNCTION_PARAMS_HPP #define BOOST_GRAPH_NAMED_FUNCTION_PARAMS_HPP #include #include #include #include #include #include #include #include #include #include #include #include #include namespace boost { struct parity_map_t { }; struct vertex_assignment_map_t { }; struct distance_compare_t { }; struct distance_combine_t { }; struct distance_inf_t { }; struct distance_zero_t { }; struct buffer_param_t { }; struct edge_copy_t { }; struct vertex_copy_t { }; struct vertex_isomorphism_t { }; struct vertex_invariant_t { }; struct vertex_invariant1_t { }; struct vertex_invariant2_t { }; struct edge_compare_t { }; struct vertex_max_invariant_t { }; struct orig_to_copy_t { }; struct root_vertex_t { }; struct polling_t { }; struct lookahead_t { }; struct in_parallel_t { }; struct attractive_force_t { }; struct repulsive_force_t { }; struct force_pairs_t { }; struct cooling_t { }; struct vertex_displacement_t { }; struct iterations_t { }; struct diameter_range_t { }; struct learning_constant_range_t { }; struct vertices_equivalent_t { }; struct edges_equivalent_t { }; struct index_in_heap_map_t { }; struct max_priority_queue_t { }; #define BOOST_BGL_DECLARE_NAMED_PARAMS \ BOOST_BGL_ONE_PARAM_CREF(weight_map, edge_weight) \ BOOST_BGL_ONE_PARAM_CREF(weight_map2, edge_weight2) \ BOOST_BGL_ONE_PARAM_CREF(distance_map, vertex_distance) \ BOOST_BGL_ONE_PARAM_CREF(predecessor_map, vertex_predecessor) \ BOOST_BGL_ONE_PARAM_CREF(rank_map, vertex_rank) \ BOOST_BGL_ONE_PARAM_CREF(root_map, vertex_root) \ BOOST_BGL_ONE_PARAM_CREF(root_vertex, root_vertex) \ BOOST_BGL_ONE_PARAM_CREF(edge_centrality_map, edge_centrality) \ BOOST_BGL_ONE_PARAM_CREF(centrality_map, vertex_centrality) \ BOOST_BGL_ONE_PARAM_CREF(parity_map, parity_map) \ BOOST_BGL_ONE_PARAM_CREF(color_map, vertex_color) \ BOOST_BGL_ONE_PARAM_CREF(edge_color_map, edge_color) \ BOOST_BGL_ONE_PARAM_CREF(capacity_map, edge_capacity) \ BOOST_BGL_ONE_PARAM_CREF(residual_capacity_map, edge_residual_capacity) \ BOOST_BGL_ONE_PARAM_CREF(reverse_edge_map, edge_reverse) \ BOOST_BGL_ONE_PARAM_CREF(discover_time_map, vertex_discover_time) \ BOOST_BGL_ONE_PARAM_CREF(lowpoint_map, vertex_lowpoint) \ BOOST_BGL_ONE_PARAM_CREF(vertex_index_map, vertex_index) \ BOOST_BGL_ONE_PARAM_CREF(vertex_index1_map, vertex_index1) \ BOOST_BGL_ONE_PARAM_CREF(vertex_index2_map, vertex_index2) \ BOOST_BGL_ONE_PARAM_CREF(vertex_assignment_map, vertex_assignment_map) \ BOOST_BGL_ONE_PARAM_CREF(visitor, graph_visitor) \ BOOST_BGL_ONE_PARAM_CREF(distance_compare, distance_compare) \ BOOST_BGL_ONE_PARAM_CREF(distance_combine, distance_combine) \ BOOST_BGL_ONE_PARAM_CREF(distance_inf, distance_inf) \ BOOST_BGL_ONE_PARAM_CREF(distance_zero, distance_zero) \ BOOST_BGL_ONE_PARAM_CREF(edge_copy, edge_copy) \ BOOST_BGL_ONE_PARAM_CREF(vertex_copy, vertex_copy) \ BOOST_BGL_ONE_PARAM_REF(buffer, buffer_param) \ BOOST_BGL_ONE_PARAM_CREF(orig_to_copy, orig_to_copy) \ BOOST_BGL_ONE_PARAM_CREF(isomorphism_map, vertex_isomorphism) \ BOOST_BGL_ONE_PARAM_CREF(vertex_invariant, vertex_invariant) \ BOOST_BGL_ONE_PARAM_CREF(vertex_invariant1, vertex_invariant1) \ BOOST_BGL_ONE_PARAM_CREF(vertex_invariant2, vertex_invariant2) \ BOOST_BGL_ONE_PARAM_CREF(vertex_max_invariant, vertex_max_invariant) \ BOOST_BGL_ONE_PARAM_CREF(polling, polling) \ BOOST_BGL_ONE_PARAM_CREF(lookahead, lookahead) \ BOOST_BGL_ONE_PARAM_CREF(in_parallel, in_parallel) \ BOOST_BGL_ONE_PARAM_CREF(displacement_map, vertex_displacement) \ BOOST_BGL_ONE_PARAM_CREF(attractive_force, attractive_force) \ BOOST_BGL_ONE_PARAM_CREF(repulsive_force, repulsive_force) \ BOOST_BGL_ONE_PARAM_CREF(force_pairs, force_pairs) \ BOOST_BGL_ONE_PARAM_CREF(cooling, cooling) \ BOOST_BGL_ONE_PARAM_CREF(iterations, iterations) \ BOOST_BGL_ONE_PARAM_CREF(diameter_range, diameter_range) \ BOOST_BGL_ONE_PARAM_CREF(learning_constant_range, learning_constant_range) \ BOOST_BGL_ONE_PARAM_CREF(vertices_equivalent, vertices_equivalent) \ BOOST_BGL_ONE_PARAM_CREF(edges_equivalent, edges_equivalent) \ BOOST_BGL_ONE_PARAM_CREF(index_in_heap_map, index_in_heap_map) \ BOOST_BGL_ONE_PARAM_REF(max_priority_queue, max_priority_queue) template struct bgl_named_params { typedef bgl_named_params self; typedef Base next_type; typedef Tag tag_type; typedef T value_type; bgl_named_params(T v = T()) : m_value(v) { } bgl_named_params(T v, const Base& b) : m_value(v), m_base(b) { } T m_value; Base m_base; #define BOOST_BGL_ONE_PARAM_REF(name, key) \ template \ bgl_named_params, BOOST_PP_CAT(key, _t), self> \ name(PType& p) const { \ typedef bgl_named_params, BOOST_PP_CAT(key, _t), self> Params; \ return Params(boost::ref(p), *this); \ } \ #define BOOST_BGL_ONE_PARAM_CREF(name, key) \ template \ bgl_named_params \ name(const PType& p) const { \ typedef bgl_named_params Params; \ return Params(p, *this); \ } \ BOOST_BGL_DECLARE_NAMED_PARAMS #undef BOOST_BGL_ONE_PARAM_REF #undef BOOST_BGL_ONE_PARAM_CREF // Duplicate template bgl_named_params vertex_color_map(const PType& p) const {return this->color_map(p);} }; #define BOOST_BGL_ONE_PARAM_REF(name, key) \ template \ bgl_named_params, BOOST_PP_CAT(key, _t)> \ name(PType& p) { \ typedef bgl_named_params, BOOST_PP_CAT(key, _t)> Params; \ return Params(boost::ref(p)); \ } \ #define BOOST_BGL_ONE_PARAM_CREF(name, key) \ template \ bgl_named_params \ name(const PType& p) { \ typedef bgl_named_params Params; \ return Params(p); \ } \ BOOST_BGL_DECLARE_NAMED_PARAMS #undef BOOST_BGL_ONE_PARAM_REF #undef BOOST_BGL_ONE_PARAM_CREF // Duplicate template bgl_named_params vertex_color_map(const PType& p) {return color_map(p);} namespace detail { struct unused_tag_type {}; } typedef bgl_named_params no_named_parameters; //=========================================================================== // Functions for extracting parameters from bgl_named_params template struct lookup_named_param {}; template struct lookup_named_param > { typedef T type; static const T& get(const bgl_named_params& p) { return p.m_value; } }; template struct lookup_named_param > { typedef typename lookup_named_param::type type; static const type& get(const bgl_named_params& p) { return lookup_named_param::get(p.m_base); } }; template struct lookup_named_param_def { typedef Def type; static const Def& get(const Args&, const Def& def) {return def;} }; template struct lookup_named_param_def, Def> { typedef T type; static const type& get(const bgl_named_params& p, const Def&) { return p.m_value; } }; template struct lookup_named_param_def, Def> { typedef typename lookup_named_param_def::type type; static const type& get(const bgl_named_params& p, const Def& def) { return lookup_named_param_def::get(p.m_base, def); } }; struct param_not_found {}; template struct get_param_type: lookup_named_param_def {}; template inline const typename lookup_named_param_def::type& get_param(const Args& p, Tag) { return lookup_named_param_def::get(p, param_not_found()); } template const P& choose_param(const P& param, const Default&) { return param; } template Default choose_param(const param_not_found&, const Default& d) { return d; } template inline bool is_default_param(const T&) { return false; } inline bool is_default_param(const param_not_found&) { return true; } namespace detail { template struct const_type_as_type {typedef typename T::const_type type;}; } // namespace detail // Use this function instead of choose_param() when you want // to avoid requiring get(tag, g) when it is not used. namespace detail { template struct choose_impl_result: boost::mpl::eval_if< boost::is_same, boost::mpl::eval_if< GraphIsConst, detail::const_type_as_type >, property_map >, boost::mpl::identity > {}; // Parameters of f are (GraphIsConst, Graph, Param, Tag) template struct choose_impl_helper; template <> struct choose_impl_helper { template static typename property_map::const_type f(boost::mpl::true_, const Graph& g, const Param&, PropertyTag tag) { return get(tag, g); } template static typename property_map::type f(boost::mpl::false_, Graph& g, const Param&, PropertyTag tag) { return get(tag, g); } }; template <> struct choose_impl_helper { template static Param f(GraphIsConst, const Graph&, const Param& p, PropertyTag) { return p; } }; } template typename detail::choose_impl_result::type choose_const_pmap(const Param& p, const Graph& g, PropertyTag tag) { return detail::choose_impl_helper::value> ::f(boost::mpl::true_(), g, p, tag); } template typename detail::choose_impl_result::type choose_pmap(const Param& p, Graph& g, PropertyTag tag) { return detail::choose_impl_helper::value> ::f(boost::mpl::false_(), g, p, tag); } namespace detail { // used in the max-flow algorithms template struct edge_capacity_value { typedef bgl_named_params Params; typedef typename detail::choose_impl_result::type, edge_capacity_t>::type CapacityEdgeMap; typedef typename property_traits::value_type type; }; } // Declare all new tags namespace graph { namespace keywords { #define BOOST_BGL_ONE_PARAM_REF(name, key) BOOST_PARAMETER_NAME(name) #define BOOST_BGL_ONE_PARAM_CREF(name, key) BOOST_PARAMETER_NAME(name) BOOST_BGL_DECLARE_NAMED_PARAMS #undef BOOST_BGL_ONE_PARAM_REF #undef BOOST_BGL_ONE_PARAM_CREF } } namespace detail { template struct convert_one_keyword {}; #define BOOST_BGL_ONE_PARAM_REF(name, key) \ template <> \ struct convert_one_keyword { \ typedef boost::graph::keywords::tag::name type; \ }; #define BOOST_BGL_ONE_PARAM_CREF(name, key) BOOST_BGL_ONE_PARAM_REF(name, key) BOOST_BGL_DECLARE_NAMED_PARAMS #undef BOOST_BGL_ONE_PARAM_REF #undef BOOST_BGL_ONE_PARAM_CREF template struct convert_bgl_params_to_boost_parameter { typedef typename convert_one_keyword::type new_kw; typedef boost::parameter::aux::tagged_argument tagged_arg_type; typedef convert_bgl_params_to_boost_parameter rest_conv; typedef boost::parameter::aux::arg_list type; static type conv(const T& x) { return type(tagged_arg_type(x.m_value), rest_conv::conv(x.m_base)); } }; template struct convert_bgl_params_to_boost_parameter > { typedef convert_bgl_params_to_boost_parameter rest_conv; typedef typename rest_conv::type type; static type conv(const bgl_named_params& x) { return rest_conv::conv(x.m_base); } }; template <> struct convert_bgl_params_to_boost_parameter { typedef boost::parameter::aux::empty_arg_list type; static type conv(const boost::no_property&) {return type();} }; template <> struct convert_bgl_params_to_boost_parameter { typedef boost::parameter::aux::empty_arg_list type; static type conv(const boost::no_named_parameters&) {return type();} }; struct bgl_parameter_not_found_type {}; template struct parameter_exists : boost::mpl::not_::type, bgl_parameter_not_found_type> > {}; } #define BOOST_GRAPH_DECLARE_CONVERTED_PARAMETERS(old_type, old_var) \ typedef typename boost::detail::convert_bgl_params_to_boost_parameter::type arg_pack_type; \ arg_pack_type arg_pack = boost::detail::convert_bgl_params_to_boost_parameter::conv(old_var); namespace detail { template struct override_const_property_t { typedef typename boost::remove_const::type result_type; result_type operator()(const Graph&, const ArgType& a) const {return a;} }; template struct override_const_property_t { typedef typename boost::property_map::const_type result_type; result_type operator()(const Graph& g, const ArgType&) const {return get(Prop(), g);} }; template struct override_const_property_result { typedef typename override_const_property_t< typename boost::parameter::value_type::type, Prop, Graph, boost::detail::parameter_exists::value >::result_type type; }; template typename override_const_property_result::type override_const_property(const ArgPack& ap, const boost::parameter::keyword& t, const Graph& g, Prop) { return override_const_property_t< typename boost::parameter::value_type::type, Prop, Graph, boost::detail::parameter_exists::value >()(g, ap[t | 0]); } template struct override_property_t { typedef ArgType result_type; result_type operator()(const Graph& g, const typename boost::add_reference::type a) const {return a;} }; template struct override_property_t { typedef typename boost::property_map::type result_type; result_type operator()(const Graph& g, const ArgType& a) const {return get(Prop(), g);} }; template struct override_property_result { typedef typename override_property_t< typename boost::parameter::value_type::type, Prop, Graph, boost::detail::parameter_exists::value >::result_type type; }; template typename override_property_result::type override_property(const ArgPack& ap, const boost::parameter::keyword& t, const Graph& g, Prop prop) { return override_property_t< typename boost::parameter::value_type::type, Prop, Graph, boost::detail::parameter_exists::value >()(g, ap[t | 0]); } template struct make_arg_pack_type; template <> struct make_arg_pack_type {typedef boost::parameter::aux::empty_arg_list type;}; template struct make_arg_pack_type { typedef boost::parameter::aux::tagged_argument type; }; #define BOOST_GRAPH_OPENING_PART_OF_PAIR(z, i, n) boost::parameter::aux::arg_list, #define BOOST_GRAPH_MAKE_PAIR_PARAM(z, i, _) const boost::parameter::aux::tagged_argument& BOOST_PP_CAT(kw, i) #define BOOST_GRAPH_MAKE_AP_TYPE_SPECIALIZATION(z, i, _) \ template \ struct make_arg_pack_type { \ typedef \ BOOST_PP_REPEAT(i, BOOST_GRAPH_OPENING_PART_OF_PAIR, BOOST_PP_DEC(i)) boost::parameter::aux::empty_arg_list BOOST_PP_REPEAT(i, > BOOST_PP_TUPLE_EAT(3), ~) \ type; \ }; BOOST_PP_REPEAT_FROM_TO(2, 11, BOOST_GRAPH_MAKE_AP_TYPE_SPECIALIZATION, ~) #undef BOOST_GRAPH_MAKE_AP_TYPE_SPECIALIZATION #define BOOST_GRAPH_MAKE_FORWARDING_FUNCTION(name, nfixed, nnamed_max) \ /* Entry point for conversion from BGL-style named parameters */ \ template \ typename boost::result_of< \ detail::BOOST_PP_CAT(name, _impl)(BOOST_PP_ENUM_PARAMS(nfixed, Param) BOOST_PP_COMMA_IF(nfixed) const ArgPack&) \ >::type \ BOOST_PP_CAT(name, _with_named_params)(BOOST_PP_ENUM_BINARY_PARAMS(nfixed, const Param, & param) BOOST_PP_COMMA_IF(nfixed) const ArgPack& arg_pack) { \ return detail::BOOST_PP_CAT(name, _impl)()(BOOST_PP_ENUM_PARAMS(nfixed, param) BOOST_PP_COMMA_IF(nfixed) arg_pack); \ } \ /* Individual functions taking Boost.Parameter-style keyword arguments */ \ BOOST_PP_REPEAT(BOOST_PP_INC(nnamed_max), BOOST_GRAPH_MAKE_FORWARDING_FUNCTION_ONE, (name)(nfixed)) #define BOOST_GRAPH_MAKE_FORWARDING_FUNCTION_ONE(z, nnamed, seq) \ BOOST_GRAPH_MAKE_FORWARDING_FUNCTION_ONEX(z, nnamed, BOOST_PP_SEQ_ELEM(0, seq), BOOST_PP_SEQ_ELEM(1, seq)) #define BOOST_GRAPH_MAKE_FORWARDING_FUNCTION_ONEX(z, nnamed, name, nfixed) \ template \ typename boost::result_of< \ detail::BOOST_PP_CAT(name, _impl) \ (BOOST_PP_ENUM_PARAMS(nfixed, Param) BOOST_PP_COMMA_IF(nfixed) \ const typename boost::detail::make_arg_pack_type::type&) \ >::type \ name(BOOST_PP_ENUM_BINARY_PARAMS(nfixed, const Param, & param) \ BOOST_PP_ENUM_TRAILING(nnamed, BOOST_GRAPH_MAKE_PAIR_PARAM, ~)) { \ return detail::BOOST_PP_CAT(name, _impl)() \ (BOOST_PP_ENUM_PARAMS(nfixed, param), \ (boost::parameter::aux::empty_arg_list() BOOST_PP_ENUM_TRAILING_PARAMS(nnamed, kw))); \ } #define BOOST_GRAPH_MAKE_OLD_STYLE_PARAMETER_FUNCTION(name, nfixed) \ template \ typename boost::result_of< \ ::boost::graph::detail::BOOST_PP_CAT(name, _impl) BOOST_PP_EXPR_IF(nfixed, <) BOOST_PP_ENUM_PARAMS(nfixed, Param) BOOST_PP_EXPR_IF(nfixed, >) \ (BOOST_PP_ENUM_PARAMS(nfixed, Param) BOOST_PP_COMMA_IF(nfixed) \ const typename boost::detail::convert_bgl_params_to_boost_parameter >::type &) \ >::type \ name(BOOST_PP_ENUM_BINARY_PARAMS(nfixed, const Param, & param) BOOST_PP_COMMA_IF(nfixed) const boost::bgl_named_params& old_style_params) { \ typedef boost::bgl_named_params old_style_params_type; \ BOOST_GRAPH_DECLARE_CONVERTED_PARAMETERS(old_style_params_type, old_style_params) \ return ::boost::graph::BOOST_PP_CAT(name, _with_named_params)(BOOST_PP_ENUM_PARAMS(nfixed, param) BOOST_PP_COMMA_IF(nfixed) arg_pack); \ } \ \ BOOST_PP_EXPR_IF(nfixed, template <) BOOST_PP_ENUM_PARAMS(nfixed, typename Param) BOOST_PP_EXPR_IF(nfixed, >) \ BOOST_PP_EXPR_IF(nfixed, typename) boost::result_of< \ ::boost::graph::detail::BOOST_PP_CAT(name, _impl) BOOST_PP_EXPR_IF(nfixed, <) BOOST_PP_ENUM_PARAMS(nfixed, Param) BOOST_PP_EXPR_IF(nfixed, >) \ (BOOST_PP_ENUM_PARAMS(nfixed, Param) BOOST_PP_COMMA_IF(nfixed) const boost::parameter::aux::empty_arg_list &) \ >::type \ name(BOOST_PP_ENUM_BINARY_PARAMS(nfixed, const Param, & param)) { \ BOOST_GRAPH_DECLARE_CONVERTED_PARAMETERS(boost::no_named_parameters, boost::no_named_parameters()) \ return ::boost::graph::BOOST_PP_CAT(name, _with_named_params)(BOOST_PP_ENUM_PARAMS(nfixed, param) BOOST_PP_COMMA_IF(nfixed) arg_pack); \ } } namespace detail { template struct map_maker_helper { typedef PM map_type; static PM make_map(const Graph&, Value, const PM& pm, const ArgPack&) { return pm; } }; template struct map_maker_helper { typedef typename boost::remove_const< typename override_const_property_t< typename boost::parameter::value_type< ArgPack, boost::graph::keywords::tag::vertex_index_map, int>::type, boost::vertex_index_t, Graph, boost::detail::parameter_exists< ArgPack, boost::graph::keywords::tag::vertex_index_map>::value >::result_type>::type vi_map_type; typedef boost::shared_array_property_map map_type; static map_type make_map(const Graph& g, Value v, const PM&, const ArgPack& ap) { return make_shared_array_property_map( num_vertices(g), v, override_const_property( ap, boost::graph::keywords::_vertex_index_map, g, vertex_index)); } }; template struct map_maker { BOOST_STATIC_CONSTANT( bool, has_map = (parameter_exists ::value)); typedef map_maker_helper::type >::type> helper; typedef typename helper::map_type map_type; static map_type make_map(const Graph& g, const ArgPack& ap, ValueType default_value) { return helper::make_map(g, default_value, ap[::boost::parameter::keyword::instance | 0], ap); } }; template class make_property_map_from_arg_pack_gen { ValueType default_value; public: make_property_map_from_arg_pack_gen(ValueType default_value) : default_value(default_value) {} template typename map_maker::map_type operator()(const Graph& g, const ArgPack& ap) const { return map_maker::make_map(g, ap, default_value); } }; template class make_property_map_from_arg_pack_gen { public: template typename map_maker::map_type operator()(const Graph& g, const ArgPack& ap, ValueType default_value) const { return map_maker::make_map(g, ap, default_value); } }; static const make_property_map_from_arg_pack_gen< boost::graph::keywords::tag::color_map, default_color_type> make_color_map_from_arg_pack(white_color); template struct priority_queue_maker_helper { typedef Q priority_queue_type; static priority_queue_type make_queue(const Graph& g, const ArgPack& ap, KeyT defaultKey, const Q& q) { return q; } }; template struct priority_queue_maker_helper { typedef typename std::vector::size_type default_index_in_heap_type; typedef typename map_maker::helper::map_type index_in_heap_map; typedef boost::d_ary_heap_indirect::helper::map_type, Compare> priority_queue_type; static priority_queue_type make_queue(const Graph& g, const ArgPack& ap, KeyT defaultKey, const Q& q) { return priority_queue_type( map_maker::make_map(g, ap, defaultKey), map_maker::make_map(g, ap, typename boost::property_traits::value_type(-1)) ); } }; template struct priority_queue_maker { BOOST_STATIC_CONSTANT( bool, g_hasQ = (parameter_exists ::value)); typedef boost::reference_wrapper int_refw; typedef typename boost::parameter::value_type< ArgPack, PriorityQueueTag, int_refw >::type param_value_type_wrapper; typedef typename param_value_type_wrapper::type param_value_type; typedef typename boost::remove_const::type param_value_type_no_const; typedef priority_queue_maker_helper helper; typedef typename helper::priority_queue_type priority_queue_type; static priority_queue_type make_queue(const Graph& g, const ArgPack& ap, KeyT defaultKey) { return helper::make_queue(g, ap, defaultKey, ap[::boost::parameter::keyword::instance | 0]); } }; template , class KeyMapTag = boost::graph::keywords::tag::distance_map, class IndexInHeapMapTag = boost::graph::keywords::tag::index_in_heap_map> struct make_priority_queue_from_arg_pack_gen { KeyT defaultKey; make_priority_queue_from_arg_pack_gen(KeyT defaultKey_) : defaultKey(defaultKey_) { } template struct result { typedef typename remove_const::arg1_type>::type>::type graph_type; typedef typename remove_const::arg2_type>::type>::type arg_pack_type; typedef typename priority_queue_maker::priority_queue_type type; }; template typename priority_queue_maker::priority_queue_type operator()(const Graph& g, const ArgPack& ap) const { return priority_queue_maker::make_queue(g, ap, defaultKey); } }; template typename boost::graph_traits::vertex_descriptor get_null_vertex(const G&) {return boost::graph_traits::null_vertex();} template typename boost::graph_traits::vertex_descriptor get_default_starting_vertex(const G& g) { std::pair::vertex_iterator, typename boost::graph_traits::vertex_iterator> iters = vertices(g); return (iters.first == iters.second) ? boost::graph_traits::null_vertex() : *iters.first; } template struct get_default_starting_vertex_t { typedef typename boost::graph_traits::vertex_descriptor result_type; const G& g; get_default_starting_vertex_t(const G& g): g(g) {} result_type operator()() const {return get_default_starting_vertex(g);} }; } // namespace detail } // namespace boost #undef BOOST_BGL_DECLARE_NAMED_PARAMS #endif // BOOST_GRAPH_NAMED_FUNCTION_PARAMS_HPP