119 lines
2.7 KiB
C++
119 lines
2.7 KiB
C++
/* 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 COMPARISON_HH
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#define COMPARISON_HH
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#include "filter.hh"
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#include "expression.hh"
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#include "attribute.hh"
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namespace mapnik
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{
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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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};
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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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};
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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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};
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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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};
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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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};
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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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};
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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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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_HH
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