mapnik/include/mapnik/feature_kv_iterator.hpp

94 lines
2.7 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2012 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_FEATURE_KV_ITERATOR_HPP
#define MAPNIK_FEATURE_KV_ITERATOR_HPP
// mapnik
#include <mapnik/config.hpp>
#include <mapnik/value.hpp>
// boost
#include <boost/tuple/tuple.hpp>
#include <boost/iterator/iterator_traits.hpp>
#include <boost/iterator/iterator_facade.hpp>
#include <boost/iterator/filter_iterator.hpp>
#include <boost/variant.hpp>
// stl
#include <map>
namespace mapnik {
class feature_impl;
class MAPNIK_DECL feature_kv_iterator :
public boost::iterator_facade<feature_kv_iterator,
boost::tuple<std::string , value> const,
boost::forward_traversal_tag>
{
public:
typedef boost::tuple<std::string,value> value_type;
feature_kv_iterator (feature_impl const& f, bool begin = false);
private:
friend class boost::iterator_core_access;
void increment();
void decrement();
void advance(boost::iterator_difference<feature_kv_iterator>::type);
bool equal( feature_kv_iterator const& other) const;
value_type const& dereference() const;
feature_impl const& f_;
std::map<std::string,std::size_t>::const_iterator itr_;
mutable value_type kv_;
};
struct is_null : public boost::static_visitor<bool>
{
bool operator() (value_null const& val) const
{
return true;
}
template <typename T>
bool operator() (T val) const
{
return false;
}
};
struct value_not_null
{
bool operator() (feature_kv_iterator::value_type const& kv) const
{
return !boost::apply_visitor(is_null(),boost::get<1>(kv).base());
}
};
typedef boost::filter_iterator<value_not_null, feature_kv_iterator> feature_kv_iterator2;
}
#endif // MAPNIK_FEATURE_KV_ITERATOR_HPP