296 lines
7.8 KiB
C++
296 lines
7.8 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) 2006 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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//$Id: quadtree.hh 17 2005-03-08 23:58:43Z pavlenko $
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#ifndef QUADTREE_HH
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#define QUADTREE_HH
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#include "envelope.hpp"
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#include <vector>
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#include <fstream>
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using namespace mapnik;
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template <typename T>
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struct quadtree_node
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{
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Envelope<double> ext_;
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std::vector<T> data_;
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quadtree_node<T>* children_[4];
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quadtree_node(const Envelope<double>& ext)
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: ext_(ext),data_()
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{
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memset(children_,0,sizeof(quadtree_node<T>*)*4);
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}
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~quadtree_node()
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{
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for (int i=0;i<4;++i)
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{
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if (children_[i])
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{
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delete children_[i],children_[i]=0;
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}
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}
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}
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int num_subnodes() const
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{
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int count=0;
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for (int i=0;i<4;++i)
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{
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if (children_[i])
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{
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++count;
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}
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}
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return count;
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}
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};
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template <typename T>
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class quadtree
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{
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private:
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quadtree_node<T>* root_;
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const int maxdepth_;
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const double ratio_;
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public:
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quadtree(const Envelope<double>& extent,int maxdepth,double ratio)
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: root_(new quadtree_node<T>(extent)),
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maxdepth_(maxdepth),
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ratio_(ratio) {}
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~quadtree()
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{
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if (root_) delete root_;
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}
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void insert(const T& data,const Envelope<double>& item_ext)
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{
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insert(data,item_ext,root_,maxdepth_);
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}
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int count() const
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{
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return count_nodes(root_);
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}
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int count_items() const
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{
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int count=0;
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count_items(root_,count);
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return count;
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}
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void print() const
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{
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print(root_);
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}
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void trim()
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{
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trim_tree(root_);
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}
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void write(std::ostream& out)
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{
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char header[16];
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memset(header,0,16);
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header[0]='m';
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header[1]='a';
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header[2]='p';
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header[4]='n';
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header[5]='i';
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header[6]='k';
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out.write(header,16);
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write_node(out,root_);
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}
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private:
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void trim_tree(quadtree_node<T>*& node)
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{
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if (node)
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{
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for (int i=0;i<4;++i)
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{
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trim_tree(node->children_[i]);
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}
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if (node->num_subnodes()==1 && node->data_.size()==0)
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{
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for (int i=0;i<4;++i)
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{
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if (node->children_[i])
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{
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node=node->children_[i];
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break;
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}
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}
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}
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}
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}
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int count_nodes(const quadtree_node<T>* node) const
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{
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if (!node)
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{
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return 0;
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}
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else
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{
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int count = 1;
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for (int i=0;i<4;++i)
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{
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count += count_nodes(node->children_[i]);
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}
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return count;
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}
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}
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void count_items(const quadtree_node<T>* node,int& count) const
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{
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if (node)
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{
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count += node->data_.size();
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for (int i=0;i<4;++i)
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{
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count_items(node->children_[i],count);
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}
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}
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}
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int subnode_offset(const quadtree_node<T>* node) const
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{
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int offset=0;
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for (int i=0;i<4;i++)
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{
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if (node->children_[i])
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{
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offset +=sizeof(Envelope<double>)+(node->children_[i]->data_.size()*sizeof(T))+3*sizeof(int);
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offset +=subnode_offset(node->children_[i]);
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}
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}
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return offset;
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}
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void write_node(std::ostream& out,const quadtree_node<T>* node) const
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{
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if (node)
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{
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int offset=subnode_offset(node);
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int shape_count=node->data_.size();
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int recsize=sizeof(Envelope<double>) + 3 * sizeof(int) + shape_count * sizeof(T);
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char* node_record=new char[recsize];
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memset(node_record,0,recsize);
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memcpy(node_record,&offset,4);
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memcpy(node_record+4,&node->ext_,sizeof(Envelope<double>));
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memcpy(node_record+36,&shape_count,4);
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for (int i=0;i<shape_count;++i)
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{
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memcpy(node_record + 40 + i * sizeof(T),&(node->data_[i]),sizeof(T));
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}
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int num_subnodes=0;
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for (int i=0;i<4;++i)
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{
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if (node->children_[i])
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{
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++num_subnodes;
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}
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}
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memcpy(node_record + 40 + shape_count * sizeof(T),&num_subnodes,4);
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out.write(node_record,recsize);
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delete [] node_record;
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for (int i=0;i<4;++i)
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{
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write_node(out,node->children_[i]);
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}
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}
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}
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void print(const quadtree_node<T>* node,int level=0) const
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{
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if (node)
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{
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typename std::vector<T>::const_iterator itr=node->data_.begin();
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std::string pad;
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for (int i=0;i<level;++i)
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{
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pad+=" ";
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}
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std::clog<<pad<<"node "<<node<<" extent:"<<node->ext_<<std::endl;
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std::clog<<pad;
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while(itr!=node->data_.end())
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{
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std::clog<<*itr<<" ";
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++itr;
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}
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std::clog<<std::endl;
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for (int i=0;i<4;++i)
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{
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print(node->children_[i],level+4);
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}
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}
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}
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void insert(const T& data,const Envelope<double>& item_ext,quadtree_node<T>* node,int maxdepth)
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{
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if (node && node->ext_.contains(item_ext))
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{
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coord2d c=node->ext_.center();
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double width=node->ext_.width();
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double height=node->ext_.height();
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double lox=node->ext_.minx();
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double loy=node->ext_.miny();
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double hix=node->ext_.maxx();
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double hiy=node->ext_.maxy();
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Envelope<double> ext[4];
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ext[0]=Envelope<double>(lox,loy,lox + width * ratio_,loy + height * ratio_);
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ext[1]=Envelope<double>(hix - width * ratio_,loy,hix,loy + height * ratio_);
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ext[2]=Envelope<double>(lox,hiy - height*ratio_,lox + width * ratio_,hiy);
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ext[3]=Envelope<double>(hix - width * ratio_,hiy - height*ratio_,hix,hiy);
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if (maxdepth > 1)
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{
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for (int i=0;i<4;++i)
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{
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if (ext[i].contains(item_ext))
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{
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if (!node->children_[i])
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{
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node->children_[i]=new quadtree_node<T>(ext[i]);
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}
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insert(data,item_ext,node->children_[i],maxdepth-1);
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return;
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}
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}
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}
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node->data_.push_back(data);
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}
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}
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};
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#endif //QUADTREE_HH
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