quadtree.H

Go to the documentation of this file.

 
/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
 
 
# ifndef QUADTREE_H
# define QUADTREE_H
 
# include <quadnode.H>
 
class QuadTree 
{
public:
  using Node = QuadNode;
 
private:
  Node * root;  
 
  size_t max_num_points_per_node;
 
  void split(Node * node)
  {
    assert(node->is_leaf()); // Only applies to leaf nodes
 
    size_t next_level = LEVEL(node) + 1;
 
    NW_CHILD(node) =
      new QuadNode(node->get_min_x(), node->get_mid_x(),
                    node->get_min_y(), node->get_mid_y(), node);
    LEVEL(NW_CHILD(node)) = next_level; 
 
    NE_CHILD(node) =
      new QuadNode(node->get_mid_x(), node->get_max_x(),
                    node->get_min_y(), node->get_mid_y(), node);
    LEVEL(NE_CHILD(node)) = next_level;
 
    SW_CHILD(node) =
      new QuadNode(node->get_min_x(), node->get_mid_x(),
                    node->get_mid_y(), node->get_max_y(), node);
    LEVEL(SW_CHILD(node)) = next_level;
 
    SE_CHILD(node) =
      new QuadNode(node->get_mid_x(), node->get_max_x(),
                    node->get_mid_y(), node->get_max_y(), node);
    LEVEL(SE_CHILD(node)) = next_level;
 
    COLOR(node) = Node::Color::Gray;
 
    DynList<Point> & points = node->get_points_set();
    
    while (not points.is_empty())
      {
        Point point = points.remove_first();
 
        QuadNode * child = node->get_child_to(point);
 
        child->add_point(point);
      }
  }
 
  void join(Node * node)
  {
    assert(not node->is_leaf()); // node is not a leaf
    // All four children of node must be leaves
    assert(NW_CHILD(node)->is_leaf());
    assert(NE_CHILD(node)->is_leaf());
    assert(SW_CHILD(node)->is_leaf());
    assert(SE_CHILD(node)->is_leaf());
 
    DynList<Point> & points = node->get_points_set();
 
    DynList<Point> & nw_points = NW_CHILD(node)->get_points_set();
 
    while(not nw_points.is_empty())
      points.append(nw_points.remove_first());
 
    auto & ne_points = NE_CHILD(node)->get_points_set();
 
    while(not ne_points.is_empty())
      points.append(ne_points.remove_first());
 
    auto & sw_points = SW_CHILD(node)->get_points_set();
 
    while(not sw_points.is_empty())
      points.append(sw_points.remove_first());
 
    auto & se_points = SE_CHILD(node)->get_points_set();
 
    while(not se_points.is_empty())
      points.append(se_points.remove_first());
 
    delete NW_CHILD(node);
    NW_CHILD(node) = nullptr;
  
    delete NE_CHILD(node);
    NE_CHILD(node) = nullptr;
 
    delete SW_CHILD(node);
    SW_CHILD(node) = nullptr;
 
    delete SE_CHILD(node);
    SE_CHILD(node) = nullptr;
 
    COLOR(node) = points.is_empty() ? Node::Color::White : Node::Color::Black;
  }
 
  Point * insert(Node *& r, const Point & p)
  {
    assert(r->contains(p));
 
    if (r->is_leaf())
      {
        if (r->get_num_points() < max_num_points_per_node)
          return &r->add_point(p);
        else
          split(r);
      }
  
    Node * node = r->get_child_to(p);
 
    return insert(node, p);
  }
 
  void empty(Node *& r) noexcept
  {
    if (r == nullptr)
      return;
 
    empty(NW_CHILD(r));
    empty(NE_CHILD(r));
    empty(SW_CHILD(r));
    empty(SE_CHILD(r));
 
    delete r;
    r = nullptr;
  }
 
  template <class Op>
  void operate_on_nodes(Node * r, Op & op)
  {
    if (r == nullptr)
      return;
 
    op(r);
 
    operate_on_nodes<Op> (NW_CHILD(r), op);
    operate_on_nodes<Op> (NE_CHILD(r), op);
    operate_on_nodes<Op> (SW_CHILD(r), op);
    operate_on_nodes<Op> (SE_CHILD(r), op);
  }
 
  void copy_tree(QuadNode * src, QuadNode *& tgt,
                 QuadNode * tgt_parent = nullptr)
  {
    if (src == nullptr)
      return;
 
    tgt = new QuadNode(src->get_min_x(), src->get_max_x(),
                        src->get_min_y(), src->get_max_y(), tgt_parent);
 
    tgt->get_points_set() = src->get_points_set();
 
    COLOR(tgt) = COLOR(src);
    LEVEL(tgt) = LEVEL(src);
 
    copy_tree(NW_CHILD(src), NW_CHILD(tgt), tgt);
    copy_tree(NE_CHILD(src), NE_CHILD(tgt), tgt);
    copy_tree(SW_CHILD(src), SW_CHILD(tgt), tgt);
    copy_tree(SE_CHILD(src), SE_CHILD(tgt), tgt);
  }
 
public:
 
  QuadTree()
    : root(new Node), max_num_points_per_node(1)
  {
    // Empty
  }
  
  QuadTree(const Geom_Number & min_x, const Geom_Number & max_x,
     const Geom_Number & min_y, const Geom_Number & max_y,
     const size_t & _max_num_points_per_node = 1)
    : root(new Node(min_x, max_x, min_y, max_y)),
      max_num_points_per_node(_max_num_points_per_node)
  {
    // Empty
  }
  
  QuadTree(const QuadTree & tree)
    : root(nullptr), max_num_points_per_node(tree.max_num_points_per_node)
  {
    copy_tree(tree.root, root);
  }
 
  QuadTree(QuadTree && tree) noexcept
    : root(tree.root), max_num_points_per_node(tree.max_num_points_per_node)
  {
    tree.root = nullptr;
  }
 
  QuadTree & operator = (const QuadTree & tree)
  {
    if (this == &tree)
      return *this;
 
    empty(root);
    max_num_points_per_node = tree.max_num_points_per_node;
    copy_tree(tree.root, root);
 
    return *this;
  }
 
  QuadTree & operator = (QuadTree && tree) noexcept
  {
    if (this != &tree)
      {
        empty(root);
        root = tree.root;
        max_num_points_per_node = tree.max_num_points_per_node;
        tree.root = nullptr;
      }
    return *this;
  }
 
  ~QuadTree()
  {
    empty(root);
  }
 
  [[nodiscard]] Node * get_root() noexcept
  {
    return root;
  }
 
  [[nodiscard]] const Node * get_root() const noexcept
  {
    return root;
  }
 
  void set_max_num_points_per_node(const size_t & _max_num_points_per_node) noexcept
  {
    max_num_points_per_node = _max_num_points_per_node;
  }
 
  [[nodiscard]] size_t get_max_num_points_per_node() const noexcept
  {
    return max_num_points_per_node;
  }
 
  [[nodiscard]] bool contains(const Point & p) const noexcept
  {
    return root->contains(p);
  }
 
  Point * insert(const Point & p)
  {
    if (not root->contains(p))
      return nullptr;
 
    return insert(root, p);
  }
 
  Point * insert(const Geom_Number & x, const Geom_Number & y)
  {
    return insert(Point(x, y));
  }
  
  [[nodiscard]] Point * search(const Point & p) noexcept
  {
    if (not root->contains(p))
      return nullptr;
 
    Node * aux = root;
 
    while (not aux->is_leaf())
      aux = aux->get_child_to(p);
 
    return aux->search_point(p);
  }
 
  [[nodiscard]] Node * search_container_node(const Point & p) noexcept
  {
    if (not root->contains(p))
      return nullptr;
 
    Node * aux = root;
 
    while (not aux->is_leaf())
      aux = aux->get_child_to(p);
 
    if (aux->search_point(p) == nullptr)
      return nullptr;
 
    return aux;
  }
 
  void remove(const Point & p)
  {
    Node * aux = root;
 
    while (not aux->is_leaf())
      aux = aux->get_child_to(p);
 
    if (not aux->remove_point(p))
      return;
 
    Node * parent = PARENT(aux);
 
    if (parent == nullptr)
      return;
 
    if (NW_CHILD(parent)->get_num_points() +
        NE_CHILD(parent)->get_num_points() +
        SW_CHILD(parent)->get_num_points() +
        SE_CHILD(parent)->get_num_points() <= max_num_points_per_node)
      join(parent);
  }
 
  void empty()
  {
    empty(NW_CHILD(root));
    empty(NE_CHILD(root));
    empty(SW_CHILD(root));
    empty(SE_CHILD(root));
    root->empty();
  }
 
  template <class Op>
  void for_each(Op & op)
  {
    operate_on_nodes <Op> (root, op);
  }
 
  template <class Op>
  void for_each(Op && op = Op())
  { 
    operate_on_nodes <Op> (root, op);
  }
};
 
# endif // QUADTREE_H