/***************************************************************************** * * 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 * *****************************************************************************/ #ifndef OGR_INDEX_HPP #define OGR_INDEX_HPP // stl #include <fstream> #include <vector> // mapnik #include <mapnik/geometry/box2d.hpp> #include <mapnik/query.hpp> using mapnik::box2d; using mapnik::query; template<typename filterT, typename IStream = std::ifstream> class ogr_index { public: static void query(const filterT& filter, IStream& file, std::vector<int>& pos); private: ogr_index(); ~ogr_index(); ogr_index(const ogr_index&); ogr_index& operator=(const ogr_index&); static int read_ndr_integer(IStream& in); static void read_envelope(IStream& in, box2d<double>& envelope); static void query_node(const filterT& filter, IStream& in, std::vector<int>& pos); }; template<typename filterT, typename IStream> void ogr_index<filterT, IStream>::query(const filterT& filter, IStream& file, std::vector<int>& pos) { file.seekg(16, std::ios::beg); query_node(filter, file, pos); } template<typename filterT, typename IStream> void ogr_index<filterT, IStream>::query_node(const filterT& filter, IStream& file, std::vector<int>& ids) { const int offset = read_ndr_integer(file); box2d<double> node_ext; read_envelope(file, node_ext); const int num_shapes = read_ndr_integer(file); if (!filter.pass(node_ext)) { file.seekg(offset + num_shapes * 4 + 4, std::ios::cur); return; } for (int i = 0; i < num_shapes; ++i) { const int id = read_ndr_integer(file); ids.push_back(id); } const int children = read_ndr_integer(file); for (int j = 0; j < children; ++j) { query_node(filter, file, ids); } } template<typename filterT, typename IStream> int ogr_index<filterT, IStream>::read_ndr_integer(IStream& file) { char b[4]; file.read(b, 4); return (b[0] & 0xff) | (b[1] & 0xff) << 8 | (b[2] & 0xff) << 16 | (b[3] & 0xff) << 24; } template<typename filterT, typename IStream> void ogr_index<filterT, IStream>::read_envelope(IStream& file, box2d<double>& envelope) { file.read(reinterpret_cast<char*>(&envelope), sizeof(envelope)); } #endif // OGR_INDEX_HPP