63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
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/* This file is part of Mapnik (c++ mapping toolkit)
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* Copyright (C) 2005 Artem Pavlenko
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*
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* Mapnik is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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//$Id$
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#ifndef ATTRIBUTE_COLLECTOR
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#define ATTROBUTE_COLLECTOR
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#include "filter.hpp"
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#include "expression.hpp"
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#include "feature_layer_desc.hpp"
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#include <set>
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namespace mapnik
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{
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template <typename FeatureT>
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class attribute_collector : public filter_visitor<FeatureT>
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{
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public:
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attribute_collector(std::set<std::string>& names)
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: names_(names) {}
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void visit(filter<FeatureT>& /*filter*/)
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{
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//not interested
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}
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void visit(expression<FeatureT>& exp)
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{
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property<FeatureT>* pf;
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if ((pf = dynamic_cast<property<FeatureT>*>(&exp)))
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{
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names_.insert(pf->name());
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}
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}
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virtual ~attribute_collector() {}
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private:
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// no copying
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attribute_collector(attribute_collector const&);
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attribute_collector& operator=(attribute_collector const&);
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private:
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std::set<std::string>& names_;
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};
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}
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#endif //ATTRIBUTE_COLLECTOR_HPP
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