mapnik/include/mapnik/expression_evaluator.hpp
2013-05-06 12:38:41 -07:00

125 lines
4.1 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2011 Artem Pavlenko
*
* 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,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* 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
*
*****************************************************************************/
#ifndef MAPNIK_EXPRESSION_EVALUATOR_HPP
#define MAPNIK_EXPRESSION_EVALUATOR_HPP
// mapnik
#include <mapnik/attribute.hpp>
#include <mapnik/unicode.hpp>
#include <mapnik/expression_node.hpp>
// boost
#include <boost/variant/static_visitor.hpp>
#include <boost/variant/apply_visitor.hpp>
#include <boost/regex.hpp>
#if defined(BOOST_REGEX_HAS_ICU)
#include <boost/regex/icu.hpp>
#endif
namespace mapnik
{
template <typename T0, typename T1>
struct evaluate : boost::static_visitor<T1>
{
typedef T0 feature_type;
typedef T1 value_type;
explicit evaluate(feature_type const& f)
: feature_(f) {}
value_type operator() (value_type x) const
{
return x;
}
value_type operator() (attribute const& attr) const
{
return attr.value<value_type,feature_type>(feature_);
}
value_type operator() (geometry_type_attribute const& geom) const
{
return geom.value<value_type,feature_type>(feature_);
}
value_type operator() (binary_node<tags::logical_and> const & x) const
{
return (boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.left).to_bool())
&& (boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.right).to_bool());
}
value_type operator() (binary_node<tags::logical_or> const & x) const
{
return (boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.left).to_bool())
|| (boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.right).to_bool());
}
template <typename Tag>
value_type operator() (binary_node<Tag> const& x) const
{
typename make_op<Tag>::type operation;
return operation(boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.left),
boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.right));
}
template <typename Tag>
value_type operator() (unary_node<Tag> const& x) const
{
typename make_op<Tag>::type func;
return func(boost::apply_visitor(*this, x.expr));
}
value_type operator() (unary_node<tags::logical_not> const& x) const
{
return ! (boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.expr).to_bool());
}
value_type operator() (regex_match_node const& x) const
{
value_type v = boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.expr);
#if defined(BOOST_REGEX_HAS_ICU)
return boost::u32regex_match(v.to_unicode(),x.pattern);
#else
return boost::regex_match(v.to_string(),x.pattern);
#endif
}
value_type operator() (regex_replace_node const& x) const
{
value_type v = boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.expr);
#if defined(BOOST_REGEX_HAS_ICU)
return boost::u32regex_replace(v.to_unicode(),x.pattern,x.format);
#else
std::string repl = boost::regex_replace(v.to_string(),x.pattern,x.format);
mapnik::transcoder tr_("utf8");
return tr_.transcode(repl.c_str());
#endif
}
feature_type const& feature_;
};
}
#endif // MAPNIK_EXPRESSION_EVALUATOR_HPP