128 lines
3.3 KiB
C++
128 lines
3.3 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 MATH_EXPR_HPP
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#define MATH_EXPR_HPP
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#include <mapnik/expression.hpp>
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namespace mapnik
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{
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template <typename T>
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struct add
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{
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T operator () (T const& left, T const& right)
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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 sub
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{
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T operator () (T const& left, T const& right)
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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 mult
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{
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T operator () (T const& left, T const& right)
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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 div
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{
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T operator () (T const& left, T const& right)
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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 math_expr_b : public expression<FeatureT>
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{
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math_expr_b(expression<FeatureT> const& left,
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expression<FeatureT> const& right)
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: expression<FeatureT>(),
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left_(left.clone()),
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right_(right.clone()) {}
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math_expr_b(math_expr_b const& other)
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: expression<FeatureT>(),
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left_(other.left_->clone()),
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right_(other.right_->clone()) {}
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value get_value(FeatureT const& 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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expression<FeatureT>* clone() const
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{
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return new math_expr_b<FeatureT,Op>(*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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~math_expr_b()
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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 //
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