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/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2024 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/util/utf_conv_win.hpp>
#include <mapnik/util/conversions.hpp>
#include <mapnik/geometry/is_empty.hpp>
#include <mapnik/json/parse_feature.hpp>
#include <mapnik/json/json_grammar_config.hpp>
// stl
#include <string>
#include <vector>
#include <fstream>
#include <algorithm>
geojson_index_featureset::geojson_index_featureset(std::string const& filename,
mapnik::bounding_box_filter<float> const& filter)
:
#if defined(MAPNIK_MEMORY_MAPPED_FILE)
//
#elif defined(_WIN32)
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)
const auto memory = mapnik::mapped_memory_cache::instance().find(filename, true);
if (memory.has_value())
{
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::bounding_box_filter<float>, std::ifstream, mapnik::box2d<float>>::
query(filter, index, positions_);
positions_.erase(std::remove_if(positions_.begin(),
positions_.end(),
[&](value_type const& pos) { return !pos.box.intersects(filter.box_); }),
positions_.end());
std::sort(positions_.begin(), positions_.end(), [](value_type const& lhs, value_type const& rhs) {
return lhs.off < rhs.off;
});
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 = static_cast<char const*>(mapped_region_->get_address()) + pos.off;
char const* end = start + pos.size;
#else
std::fseek(file_.get(), pos.off, SEEK_SET);
std::vector<char> record;
record.resize(pos.size);
auto count = std::fread(record.data(), pos.size, 1, file_.get());
auto const* start = record.data();
auto const* end = (count == 1) ? start + record.size() : start;
#endif
static const mapnik::transcoder tr("utf8");
mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx_, feature_id_++));
using mapnik::json::grammar::iterator_type;
mapnik::json::parse_feature(start, end, *feature, tr); // throw on failure
// skip empty geometries
if (mapnik::geometry::is_empty(feature->get_geometry()))
continue;
return feature;
}
return mapnik::feature_ptr();
}
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