mapnik/include/comparison.hpp
2005-06-14 15:06:59 +00:00

150 lines
3.2 KiB
C++

/* This file is part of Mapnik (c++ mapping toolkit)
* Copyright (C) 2005 Artem Pavlenko
*
* Mapnik is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
//$Id$
#ifndef COMPARISON_HPP
#define COMPARISON_HPP
#include "filter.hpp"
#include "expression.hpp"
#include "attribute.hpp"
#include <iostream>
namespace mapnik
{
template <typename T>
struct greater_than
{
bool operator() (T const& left, T const& right) const
{
return left > right;
}
static std::string to_string()
{
return ">";
}
};
template <typename T>
struct greater_than_or_equal
{
bool operator() (T const& left, T const& right) const
{
return left >= right;
}
static std::string to_string()
{
return ">=";
}
};
template <typename T>
struct less_than
{
bool operator() (T const& left, T const& right) const
{
return left < right;
}
static std::string to_string()
{
return "<";
}
};
template <typename T>
struct less_than_or_equal
{
bool operator() (T const& left, T const& right) const
{
return left <= right;
}
static std::string to_string()
{
return "<=";
}
};
template <typename T>
struct equals
{
bool operator() (T const& left, T const& right) const
{
return left == right;
}
static std::string to_string()
{
return "=";
}
};
template <typename T>
struct not_equals
{
bool operator() (T const& left, T const& right) const
{
return left != right;
}
static std::string to_string()
{
return "<>";
}
};
template <typename FeatureT,typename Op>
struct compare_filter : public filter<FeatureT>
{
compare_filter(expression<FeatureT> const& left,
expression<FeatureT> const& right)
: filter<FeatureT>(),
left_(left.clone()), right_(right.clone()) {}
compare_filter(compare_filter const& other)
: filter<FeatureT>(),
left_(other.left_->clone()),right_(other.right_->clone()) {}
bool pass(const FeatureT& feature) const
{
return Op()(left_->get_value(feature),right_->get_value(feature));
}
void accept(filter_visitor<FeatureT>& v)
{
left_->accept(v);
right_->accept(v);
v.visit(*this);
}
std::string to_string() const
{
return "("+left_->to_string()+Op::to_string()+right_->to_string()+")";
}
filter<FeatureT>* clone() const
{
return new compare_filter<FeatureT,Op>(*this);
}
virtual ~compare_filter()
{
delete left_;
delete right_;
}
private:
expression<FeatureT>* left_;
expression<FeatureT>* right_;
};
}
#endif //COMPARISON_HPP