293 lines
9.1 KiB
C++
293 lines
9.1 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2024 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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#include "topojson_datasource.hpp"
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#include "topojson_featureset.hpp"
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// boost
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#include <boost/algorithm/string.hpp>
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// mapnik
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#include <mapnik/unicode.hpp>
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#include <mapnik/value/types.hpp>
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#include <mapnik/geometry/box2d.hpp>
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#include <mapnik/geometry/boost_adapters.hpp>
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#include <mapnik/json/topojson_grammar_x3.hpp>
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#include <mapnik/json/topojson_utils.hpp>
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#include <mapnik/util/variant.hpp>
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#include <mapnik/util/file_io.hpp>
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using mapnik::datasource;
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using mapnik::parameters;
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DATASOURCE_PLUGIN_IMPL(topojson_datasource_plugin, topojson_datasource);
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DATASOURCE_PLUGIN_EXPORT(topojson_datasource_plugin);
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DATASOURCE_PLUGIN_EMPTY_AFTER_LOAD(topojson_datasource_plugin);
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DATASOURCE_PLUGIN_EMPTY_BEFORE_UNLOAD(topojson_datasource_plugin);
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struct attr_value_converter
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{
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mapnik::eAttributeType operator()(mapnik::value_integer /*val*/) const { return mapnik::Integer; }
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mapnik::eAttributeType operator()(double /*val*/) const { return mapnik::Double; }
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mapnik::eAttributeType operator()(float /*val*/) const { return mapnik::Double; }
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mapnik::eAttributeType operator()(bool /*val*/) const { return mapnik::Boolean; }
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// string, object, array
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template<typename T>
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mapnik::eAttributeType operator()(T const& /*val*/) const
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{
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return mapnik::String;
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}
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};
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struct geometry_type_visitor
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{
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int operator()(mapnik::topojson::point const&) const
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{
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return static_cast<int>(mapnik::datasource_geometry_t::Point);
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}
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int operator()(mapnik::topojson::multi_point const&) const
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{
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return static_cast<int>(mapnik::datasource_geometry_t::Point);
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}
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int operator()(mapnik::topojson::linestring const&) const
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{
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return static_cast<int>(mapnik::datasource_geometry_t::LineString);
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}
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int operator()(mapnik::topojson::multi_linestring const&) const
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{
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return static_cast<int>(mapnik::datasource_geometry_t::LineString);
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}
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int operator()(mapnik::topojson::polygon const&) const
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{
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return static_cast<int>(mapnik::datasource_geometry_t::Polygon);
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}
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int operator()(mapnik::topojson::multi_polygon const&) const
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{
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return static_cast<int>(mapnik::datasource_geometry_t::Polygon);
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}
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template<typename T>
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int operator()(T const&) const
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{
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return 0;
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}
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};
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struct collect_attributes_visitor
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{
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mapnik::layer_descriptor& desc_;
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collect_attributes_visitor(mapnik::layer_descriptor& desc)
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: desc_(desc)
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{}
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// no-op
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void operator()(mapnik::topojson::empty) {}
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//
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template<typename GeomType>
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void operator()(GeomType const& g)
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{
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if (g.props)
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{
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for (auto const& p : *g.props)
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{
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desc_.add_descriptor(
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mapnik::attribute_descriptor(std::get<0>(p),
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mapnik::util::apply_visitor(attr_value_converter(), std::get<1>(p))));
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}
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}
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}
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};
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topojson_datasource::topojson_datasource(parameters const& params)
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: datasource(params)
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, type_(datasource::Vector)
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, desc_(topojson_datasource::name(), *params.get<std::string>("encoding", "utf-8"))
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, filename_()
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, inline_string_()
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, extent_()
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, tr_(new mapnik::transcoder(*params.get<std::string>("encoding", "utf-8")))
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, tree_(nullptr)
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{
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const auto inline_string = params.get<std::string>("inline");
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if (inline_string)
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{
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inline_string_ = *inline_string;
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}
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else
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{
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const auto file = params.get<std::string>("file");
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if (!file)
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throw mapnik::datasource_exception("TopoJSON Plugin: missing <file> parameter");
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const auto base = params.get<std::string>("base");
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if (base)
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filename_ = *base + "/" + *file;
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else
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filename_ = *file;
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}
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if (!inline_string_.empty())
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{
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parse_topojson(inline_string_.c_str());
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}
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else
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{
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mapnik::util::file file(filename_);
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if (!file)
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{
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throw mapnik::datasource_exception("TopoJSON Plugin: could not open: '" + filename_ + "'");
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}
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std::string file_buffer;
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file_buffer.resize(file.size());
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auto count = std::fread(&file_buffer[0], file.size(), 1, file.get());
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if (count == 1)
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parse_topojson(file_buffer.c_str());
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}
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}
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template<typename T>
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void topojson_datasource::parse_topojson(T const& buffer)
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{
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auto itr = buffer;
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auto end = buffer + std::strlen(buffer);
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using space_type = boost::spirit::x3::standard::space_type;
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try
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{
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boost::spirit::x3::phrase_parse(itr, end, mapnik::json::grammar::topology, space_type(), topo_);
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}
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catch (boost::spirit::x3::expectation_failure<char const*> const& ex)
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{
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std::clog << "failed to parse TopoJSON..." << std::endl;
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std::clog << ex.what() << std::endl;
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std::clog << "Expected: " << ex.which();
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std::clog << " Got: \"" << std::string(ex.where(), ex.where() + 200) << "...\"" << std::endl;
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throw mapnik::datasource_exception("topojson_datasource: Failed parse TopoJSON file '" + filename_ + "'");
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}
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using values_container = std::vector<std::pair<box_type, std::size_t>>;
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values_container values;
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values.reserve(topo_.geometries.size());
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std::size_t geometry_index = 0;
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bool first = true;
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for (auto const& geom : topo_.geometries)
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{
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mapnik::box2d<double> box = mapnik::util::apply_visitor(mapnik::topojson::bounding_box_visitor(topo_), geom);
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if (box.valid())
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{
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if (first)
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{
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first = false;
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extent_ = box;
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collect_attributes_visitor assessor(desc_);
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mapnik::util::apply_visitor(std::ref(assessor), geom);
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}
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else
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{
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extent_.expand_to_include(box);
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}
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values.emplace_back(box, geometry_index);
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}
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++geometry_index;
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}
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// packing algorithm
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tree_ = std::make_unique<spatial_index_type>(values);
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}
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topojson_datasource::~topojson_datasource() {}
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const char* topojson_datasource::name()
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{
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return "topojson";
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}
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std::optional<mapnik::datasource_geometry_t> topojson_datasource::get_geometry_type() const
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{
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std::optional<mapnik::datasource_geometry_t> result;
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int multi_type = 0;
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std::size_t num_features = topo_.geometries.size();
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for (std::size_t i = 0; i < num_features && i < 5; ++i)
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{
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mapnik::topojson::geometry const& geom = topo_.geometries[i];
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int type = mapnik::util::apply_visitor(geometry_type_visitor(), geom);
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if (type > 0)
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{
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if (multi_type > 0 && multi_type != type)
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{
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result = mapnik::datasource_geometry_t::Collection;
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return result;
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}
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else
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{
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result = static_cast<mapnik::datasource_geometry_t>(type);
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}
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multi_type = type;
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}
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}
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return result;
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}
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mapnik::datasource::datasource_t topojson_datasource::type() const
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{
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return type_;
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}
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mapnik::box2d<double> topojson_datasource::envelope() const
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{
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return extent_;
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}
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mapnik::layer_descriptor topojson_datasource::get_descriptor() const
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{
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return desc_;
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}
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mapnik::featureset_ptr topojson_datasource::features(mapnik::query const& q) const
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{
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// if the query box intersects our world extent then query for features
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mapnik::box2d<double> const& box = q.get_bbox();
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if (extent_.intersects(box))
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{
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topojson_featureset::array_type index_array;
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if (tree_)
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{
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tree_->query(boost::geometry::index::intersects(box), std::back_inserter(index_array));
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return std::make_shared<topojson_featureset>(topo_, *tr_, std::move(index_array));
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}
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}
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// otherwise return an empty featureset pointer
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return mapnik::make_empty_featureset();
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}
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mapnik::featureset_ptr topojson_datasource::features_at_point(mapnik::coord2d const& pt, double tol) const
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{
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mapnik::box2d<double> query_bbox(pt, pt);
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query_bbox.pad(tol);
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mapnik::query q(query_bbox);
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for (auto const& attr_info : desc_.get_descriptors())
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{
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q.add_property_name(attr_info.get_name());
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}
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return features(q);
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}
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