mapnik/include/math_expr.hpp

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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
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* 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
* 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
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
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//$Id$
#ifndef MATH_EXPR_HPP
#define MATH_EXPR_HPP
#include "expression.hpp"
namespace mapnik
{
template <typename T>
struct add
{
T operator () (T const& left, T const& right)
{
return left + right;
}
static std::string to_string()
{
return "+";
}
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};
template <typename T>
struct sub
{
T operator () (T const& left, T const& right)
{
return left - right;
}
static std::string to_string()
{
return "-";
}
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};
template <typename T>
struct mult
{
T operator () (T const& left, T const& right)
{
return left * right;
}
static std::string to_string()
{
return "*";
}
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};
template <typename T>
struct div
{
T operator () (T const& left, T const& right)
{
return left / right;
}
static std::string to_string()
{
return "/";
}
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};
template <typename FeatureT,typename Op>
struct math_expr_b : public expression<FeatureT>
{
math_expr_b(expression<FeatureT> const& left,
expression<FeatureT> const& right)
: expression<FeatureT>(),
left_(left.clone()),
right_(right.clone()) {}
math_expr_b(math_expr_b const& other)
: expression<FeatureT>(),
left_(other.left_->clone()),
right_(other.right_->clone()) {}
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value get_value(FeatureT const& feature) const
{
return Op ()(left_->get_value(feature),right_->get_value(feature));
}
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void accept(filter_visitor<FeatureT>& v)
{
left_->accept(v);
right_->accept(v);
v.visit(*this);
}
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expression<FeatureT>* clone() const
{
return new math_expr_b<FeatureT,Op>(*this);
}
std::string to_string() const
{
return "("+left_->to_string() + Op::to_string() + right_->to_string()+")";
}
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~math_expr_b()
{
delete left_;
delete right_;
}
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private:
expression<FeatureT>* left_;
expression<FeatureT>* right_;
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};
}
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#endif //