105 lines
3 KiB
C++
105 lines
3 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) 2017 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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#ifndef OGR_INDEX_HPP
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#define OGR_INDEX_HPP
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// stl
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#include <fstream>
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#include <vector>
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// mapnik
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#include <mapnik/geometry/box2d.hpp>
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#include <mapnik/query.hpp>
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using mapnik::box2d;
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using mapnik::query;
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template <typename filterT, typename IStream = std::ifstream>
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class ogr_index
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{
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public:
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static void query(const filterT& filter, IStream& file, std::vector<int>& pos);
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private:
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ogr_index();
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~ogr_index();
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ogr_index(const ogr_index&);
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ogr_index& operator=(const ogr_index&);
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static int read_ndr_integer(IStream& in);
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static void read_envelope(IStream& in, box2d<double>& envelope);
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static void query_node(const filterT& filter, IStream& in, std::vector<int>& pos);
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};
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template <typename filterT, typename IStream>
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void ogr_index<filterT, IStream>::query(const filterT& filter,IStream & file,std::vector<int>& pos)
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{
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file.seekg(16,std::ios::beg);
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query_node(filter,file,pos);
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}
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template <typename filterT, typename IStream>
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void ogr_index<filterT,IStream>::query_node(const filterT& filter, IStream& file, std::vector<int>& ids)
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{
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const int offset = read_ndr_integer(file);
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box2d<double> node_ext;
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read_envelope(file, node_ext);
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const int num_shapes = read_ndr_integer(file);
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if (! filter.pass(node_ext))
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{
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file.seekg(offset + num_shapes * 4 + 4, std::ios::cur);
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return;
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}
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for (int i = 0; i < num_shapes; ++i)
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{
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const int id = read_ndr_integer(file);
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ids.push_back(id);
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}
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const int children = read_ndr_integer(file);
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for (int j = 0; j < children; ++j)
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{
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query_node(filter, file, ids);
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}
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}
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template <typename filterT, typename IStream>
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int ogr_index<filterT,IStream>::read_ndr_integer(IStream& file)
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{
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char b[4];
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file.read(b, 4);
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return (b[0] & 0xff) | (b[1] & 0xff) << 8 | (b[2] & 0xff) << 16 | (b[3] & 0xff) << 24;
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}
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template <typename filterT, typename IStream>
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void ogr_index<filterT, IStream>::read_envelope(IStream& file, box2d<double>& envelope)
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{
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file.read(reinterpret_cast<char*>(&envelope), sizeof(envelope));
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}
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#endif // OGR_INDEX_HPP
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