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/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2021 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
*
*****************************************************************************/
// mapnik
#include "geojson_index_featureset.hpp"
#include <mapnik/feature.hpp>
#include <mapnik/feature_factory.hpp>
#include <mapnik/json/feature_grammar.hpp>
#include <mapnik/util/utf_conv_win.hpp>
#include <mapnik/util/spatial_index.hpp>
#include <mapnik/geometry_is_empty.hpp>
// stl
#include <string>
#include <vector>
#include <fstream>
geojson_index_featureset::geojson_index_featureset(std::string const& filename, mapnik::filter_in_box const& filter)
:
#if defined(MAPNIK_MEMORY_MAPPED_FILE)
//
#elif defined _WINDOWS
file_(_wfopen(mapnik::utf8_to_utf16(filename).c_str(), L"rb"), std::fclose),
#else
file_(std::fopen(filename.c_str(),"rb"), std::fclose),
#endif
ctx_(std::make_shared<mapnik::context_type>())
{
#if defined (MAPNIK_MEMORY_MAPPED_FILE)
boost::optional<mapnik::mapped_region_ptr> memory =
mapnik::mapped_memory_cache::instance().find(filename, true);
if (memory)
{
mapped_region_ = *memory;
}
else
{
throw std::runtime_error("could not create file mapping for " + filename);
}
#else
if (!file_) throw std::runtime_error("Can't open " + filename);
#endif
std::string indexname = filename + ".index";
std::ifstream index(indexname.c_str(), std::ios::binary);
if (!index) throw mapnik::datasource_exception("GeoJSON Plugin: can't open index file " + indexname);
mapnik::util::spatial_index<value_type,
mapnik::filter_in_box,
std::ifstream>::query(filter, index, positions_);
std::sort(positions_.begin(), positions_.end(),
[](value_type const& lhs, value_type const& rhs) { return lhs.first < rhs.first;});
itr_ = positions_.begin();
}
geojson_index_featureset::~geojson_index_featureset() {}
mapnik::feature_ptr geojson_index_featureset::next()
{
while( itr_ != positions_.end())
{
auto pos = *itr_++;
#if defined(MAPNIK_MEMORY_MAPPED_FILE)
char const* start = (char const*)mapped_region_->get_address() + pos.first;
char const* end = start + pos.second;
#else
std::fseek(file_.get(), pos.first, SEEK_SET);
std::vector<char> record;
record.resize(pos.second);
std::fread(record.data(), pos.second, 1, file_.get());
auto const* start = record.data();
auto const* end = start + record.size();
#endif
static const mapnik::transcoder tr("utf8");
static const mapnik::json::feature_grammar<char const*, mapnik::feature_impl> grammar(tr);
using namespace boost::spirit;
standard::space_type space;
mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx_, feature_id_++));
if (!qi::phrase_parse(start, end, (grammar)(boost::phoenix::ref(*feature)), space) || start != end)
{
throw std::runtime_error("Failed to parse GeoJSON feature");
}
// skip empty geometries
if (mapnik::geometry::is_empty(feature->get_geometry()))
continue;
return feature;
}
return mapnik::feature_ptr();
}
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