149 lines
4 KiB
C++
149 lines
4 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2006 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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//$Id$
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#ifndef COMPARISON_HPP
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#define COMPARISON_HPP
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#include <mapnik/filter.hpp>
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#include <mapnik/expression.hpp>
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#include <mapnik/attribute.hpp>
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namespace mapnik {
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template <typename T>
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struct greater_than
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{
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bool operator() (T const& left, T const& right) const
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{
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return left > right;
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}
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static std::string to_string()
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{
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return ">";
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}
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};
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template <typename T>
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struct greater_than_or_equal
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{
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bool operator() (T const& left, T const& right) const
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{
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return left >= right;
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}
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static std::string to_string()
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{
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return ">=";
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}
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};
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template <typename T>
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struct less_than
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{
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bool operator() (T const& left, T const& right) const
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{
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return left < right;
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}
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static std::string to_string()
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{
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return "<";
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}
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};
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template <typename T>
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struct less_than_or_equal
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{
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bool operator() (T const& left, T const& right) const
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{
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return left <= right;
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}
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static std::string to_string()
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{
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return "<=";
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}
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};
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template <typename T>
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struct equals
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{
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bool operator() (T const& left, T const& right) const
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{
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return left == right;
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}
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static std::string to_string()
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{
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return "=";
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}
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};
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template <typename T>
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struct not_equals
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{
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bool operator() (T const& left, T const& right) const
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{
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return left != right;
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}
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static std::string to_string()
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{
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return "<>";
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}
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};
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template <typename FeatureT,typename Op>
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struct compare_filter : public filter<FeatureT>
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{
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compare_filter(expression<FeatureT> const& left,
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expression<FeatureT> const& right)
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: filter<FeatureT>(),
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left_(left.clone()), right_(right.clone()) {}
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compare_filter(compare_filter const& other)
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: filter<FeatureT>(),
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left_(other.left_->clone()),right_(other.right_->clone()) {}
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bool pass(const FeatureT& feature) const
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{
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return Op()(left_->get_value(feature),right_->get_value(feature));
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}
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void accept(filter_visitor<FeatureT>& v)
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{
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left_->accept(v);
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right_->accept(v);
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v.visit(*this);
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}
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std::string to_string() const
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{
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return "("+left_->to_string()+Op::to_string()+right_->to_string()+")";
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}
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filter<FeatureT>* clone() const
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{
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return new compare_filter<FeatureT,Op>(*this);
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}
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virtual ~compare_filter()
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{
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delete left_;
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delete right_;
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}
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private:
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expression<FeatureT>* left_;
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expression<FeatureT>* right_;
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};
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}
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#endif //COMPARISON_HPP
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