mapnik/plugins/input/shape/shp_index.cpp

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2005-06-14 17:06:59 +02:00
/* This file is part of Mapnik (c++ mapping toolkit)
* Copyright (C) 2005 Artem Pavlenko
*
* Mapnik is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "shp_index.hpp"
#include "geom_util.hpp"
2005-06-14 17:06:59 +02:00
template <typename filterT>
void shp_index<filterT>::query(const filterT& filter,std::ifstream& file,std::set<int>& pos)
{
file.seekg(16,std::ios::beg);
query_node(filter,file,pos);
}
template <typename filterT>
void shp_index<filterT>::query_node(const filterT& filter,std::ifstream& file,std::set<int>& ids)
{
int offset=read_ndr_integer(file);
Envelope<double> node_ext;
read_envelope(file,node_ext);
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)
{
int id=read_ndr_integer(file);
ids.insert(id);
}
int children=read_ndr_integer(file);
for (int j=0;j<children;++j)
{
query_node(filter,file,ids);
}
}
template <typename filterT>
int shp_index<filterT>::read_ndr_integer(std::ifstream& 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>
void shp_index<filterT>::read_envelope(std::ifstream& file,Envelope<double>& envelope)
{
file.read(reinterpret_cast<char*>(&envelope),sizeof(envelope));
}
template class shp_index<filter_in_box>;
template class shp_index<filter_at_point>;