279 lines
12 KiB
C++
279 lines
12 KiB
C++
/*
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Copyright 2008 Intel Corporation
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Use, modification and distribution are subject to the Boost Software License,
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Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt).
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*/
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#ifndef BOOST_POLYGON_MAX_COVER_HPP
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#define BOOST_POLYGON_MAX_COVER_HPP
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namespace boost { namespace polygon{
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template <typename Unit>
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struct MaxCover {
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typedef interval_data<Unit> Interval;
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typedef rectangle_data<Unit> Rectangle;
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class Node {
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private:
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std::vector<Node*> children_;
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std::set<Interval> tracedPaths_;
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public:
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Rectangle rect;
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Node() : children_(), tracedPaths_(), rect() {}
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Node(const Rectangle rectIn) : children_(), tracedPaths_(), rect(rectIn) {}
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typedef typename std::vector<Node*>::iterator iterator;
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inline iterator begin() { return children_.begin(); }
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inline iterator end() { return children_.end(); }
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inline void add(Node* child) { children_.push_back(child); }
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inline bool tracedPath(const Interval& ivl) const {
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return tracedPaths_.find(ivl) != tracedPaths_.end();
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}
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inline void addPath(const Interval& ivl) {
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tracedPaths_.insert(tracedPaths_.end(), ivl);
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}
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};
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typedef std::pair<std::pair<Unit, Interval>, Node* > EdgeAssociation;
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class lessEdgeAssociation : public std::binary_function<const EdgeAssociation&, const EdgeAssociation&, bool> {
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public:
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inline lessEdgeAssociation() {}
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inline bool operator () (const EdgeAssociation& elem1, const EdgeAssociation& elem2) const {
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if(elem1.first.first < elem2.first.first) return true;
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if(elem1.first.first > elem2.first.first) return false;
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return elem1.first.second < elem2.first.second;
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}
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};
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template <class cT>
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static inline void getMaxCover(cT& outputContainer, Node* node, orientation_2d orient) {
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Interval rectIvl = node->rect.get(orient);
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if(node->tracedPath(rectIvl)) {
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return;
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}
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node->addPath(rectIvl);
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if(node->begin() == node->end()) {
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//std::cout << "WRITE OUT 3: " << node->rect << std::endl;
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outputContainer.push_back(copy_construct<typename cT::value_type, Rectangle>(node->rect));
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return;
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}
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bool writeOut = true;
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for(typename Node::iterator itr = node->begin(); itr != node->end(); ++itr) {
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getMaxCover(outputContainer, *itr, orient, node->rect); //get rectangles down path
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Interval nodeIvl = (*itr)->rect.get(orient);
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if(contains(nodeIvl, rectIvl, true)) writeOut = false;
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}
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if(writeOut) {
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//std::cout << "WRITE OUT 2: " << node->rect << std::endl;
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outputContainer.push_back(copy_construct<typename cT::value_type, Rectangle>(node->rect));
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}
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}
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struct stack_element {
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inline stack_element() :
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node(), rect(), itr() {}
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inline stack_element(Node* n,
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const Rectangle& r,
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typename Node::iterator i) :
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node(n), rect(r), itr(i) {}
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Node* node;
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Rectangle rect;
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typename Node::iterator itr;
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};
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template <class cT>
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static inline void getMaxCover(cT& outputContainer, Node* node, orientation_2d orient,
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Rectangle rect) {
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//std::cout << "New Root\n";
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std::vector<stack_element> stack;
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typename Node::iterator itr = node->begin();
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do {
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//std::cout << "LOOP\n";
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//std::cout << node->rect << std::endl;
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Interval rectIvl = rect.get(orient);
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Interval nodeIvl = node->rect.get(orient);
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bool iresult = intersect(rectIvl, nodeIvl, false);
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bool tresult = !node->tracedPath(rectIvl);
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//std::cout << (itr != node->end()) << " " << iresult << " " << tresult << std::endl;
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Rectangle nextRect1 = Rectangle(rectIvl, rectIvl);
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Unit low = rect.get(orient.get_perpendicular()).low();
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Unit high = node->rect.get(orient.get_perpendicular()).high();
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nextRect1.set(orient.get_perpendicular(), Interval(low, high));
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if(iresult && tresult) {
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node->addPath(rectIvl);
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bool writeOut = true;
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//check further visibility beyond this node
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for(typename Node::iterator itr2 = node->begin(); itr2 != node->end(); ++itr2) {
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Interval nodeIvl3 = (*itr2)->rect.get(orient);
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//if a child of this node can contain the interval then we can extend through
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if(contains(nodeIvl3, rectIvl, true)) writeOut = false;
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//std::cout << "child " << (*itr2)->rect << std::endl;
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}
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Rectangle nextRect2 = Rectangle(rectIvl, rectIvl);
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Unit low2 = rect.get(orient.get_perpendicular()).low();
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Unit high2 = node->rect.get(orient.get_perpendicular()).high();
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nextRect2.set(orient.get_perpendicular(), Interval(low2, high2));
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if(writeOut) {
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//std::cout << "write out " << nextRect << std::endl;
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outputContainer.push_back(copy_construct<typename cT::value_type, Rectangle>(nextRect2));
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} else {
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//std::cout << "supress " << nextRect << std::endl;
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}
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}
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if(itr != node->end() && iresult && tresult) {
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//std::cout << "recurse into child\n";
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stack.push_back(stack_element(node, rect, itr));
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rect = nextRect1;
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node = *itr;
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itr = node->begin();
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} else {
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if(!stack.empty()) {
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//std::cout << "recurse out of child\n";
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node = stack.back().node;
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rect = stack.back().rect;
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itr = stack.back().itr;
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stack.pop_back();
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} else {
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//std::cout << "empty stack\n";
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//if there were no children of the root node
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// Rectangle nextRect = Rectangle(rectIvl, rectIvl);
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// Unit low = rect.get(orient.get_perpendicular()).low();
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// Unit high = node->rect.get(orient.get_perpendicular()).high();
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// nextRect.set(orient.get_perpendicular(), Interval(low, high));
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// outputContainer.push_back(copy_construct<typename cT::value_type, Rectangle>(nextRect));
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}
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//std::cout << "increment " << (itr != node->end()) << std::endl;
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if(itr != node->end()) {
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++itr;
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if(itr != node->end()) {
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//std::cout << "recurse into next child.\n";
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stack.push_back(stack_element(node, rect, itr));
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Interval rectIvl2 = rect.get(orient);
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Interval nodeIvl2 = node->rect.get(orient);
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/*bool iresult =*/ intersect(rectIvl2, nodeIvl2, false);
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Rectangle nextRect2 = Rectangle(rectIvl2, rectIvl2);
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Unit low2 = rect.get(orient.get_perpendicular()).low();
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Unit high2 = node->rect.get(orient.get_perpendicular()).high();
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nextRect2.set(orient.get_perpendicular(), Interval(low2, high2));
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rect = nextRect2;
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//std::cout << "rect for next child" << rect << std::endl;
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node = *itr;
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itr = node->begin();
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}
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}
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}
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} while(!stack.empty() || itr != node->end());
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}
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/* Function recursive version of getMaxCover
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Because the code is so much simpler than the loop algorithm I retain it for clarity
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template <class cT>
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static inline void getMaxCover(cT& outputContainer, Node* node, orientation_2d orient,
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const Rectangle& rect) {
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Interval rectIvl = rect.get(orient);
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Interval nodeIvl = node->rect.get(orient);
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if(!intersect(rectIvl, nodeIvl, false)) {
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return;
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}
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if(node->tracedPath(rectIvl)) {
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return;
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}
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node->addPath(rectIvl);
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Rectangle nextRect(rectIvl, rectIvl);
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Unit low = rect.get(orient.get_perpendicular()).low();
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Unit high = node->rect.get(orient.get_perpendicular()).high();
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nextRect.set(orient.get_perpendicular(), Interval(low, high));
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bool writeOut = true;
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rectIvl = nextRect.get(orient);
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for(typename Node::iterator itr = node->begin(); itr != node->end(); ++itr) {
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nodeIvl = (*itr)->rect.get(orient);
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if(contains(nodeIvl, rectIvl, true)) writeOut = false;
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}
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if(writeOut) {
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outputContainer.push_back(copy_construct<typename cT::value_type, Rectangle>(nextRect));
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}
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for(typename Node::iterator itr = node->begin(); itr != node->end(); ++itr) {
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getMaxCover(outputContainer, *itr, orient, nextRect);
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}
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}
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*/
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//iterator range is assummed to be in topological order meaning all node's trailing
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//edges are in sorted order
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template <class iT>
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static inline void computeDag(iT beginNode, iT endNode, orientation_2d orient,
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std::size_t size) {
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std::vector<EdgeAssociation> leadingEdges;
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leadingEdges.reserve(size);
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for(iT iter = beginNode; iter != endNode; ++iter) {
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Node* nodep = &(*iter);
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Unit leading = nodep->rect.get(orient.get_perpendicular()).low();
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Interval rectIvl = nodep->rect.get(orient);
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leadingEdges.push_back(EdgeAssociation(std::pair<Unit, Interval>(leading, rectIvl), nodep));
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}
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std::sort(leadingEdges.begin(), leadingEdges.end(), lessEdgeAssociation());
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typename std::vector<EdgeAssociation>::iterator leadingBegin = leadingEdges.begin();
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iT trailingBegin = beginNode;
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while(leadingBegin != leadingEdges.end()) {
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EdgeAssociation& leadingSegment = (*leadingBegin);
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Unit trailing = (*trailingBegin).rect.get(orient.get_perpendicular()).high();
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Interval ivl = (*trailingBegin).rect.get(orient);
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std::pair<Unit, Interval> trailingSegment(trailing, ivl);
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if(leadingSegment.first.first < trailingSegment.first) {
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++leadingBegin;
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continue;
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}
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if(leadingSegment.first.first > trailingSegment.first) {
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++trailingBegin;
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continue;
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}
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if(leadingSegment.first.second.high() <= trailingSegment.second.low()) {
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++leadingBegin;
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continue;
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}
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if(trailingSegment.second.high() <= leadingSegment.first.second.low()) {
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++trailingBegin;
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continue;
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}
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//leading segment intersects trailing segment
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(*trailingBegin).add((*leadingBegin).second);
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if(leadingSegment.first.second.high() > trailingSegment.second.high()) {
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++trailingBegin;
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continue;
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}
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if(trailingSegment.second.high() > leadingSegment.first.second.high()) {
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++leadingBegin;
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continue;
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}
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++leadingBegin;
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++trailingBegin;
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}
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}
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template <class cT>
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static inline void getMaxCover(cT& outputContainer,
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const std::vector<Rectangle>& rects, orientation_2d orient) {
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if(rects.empty()) return;
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std::vector<Node> nodes;
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{
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if(rects.size() == 1) {
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outputContainer.push_back(copy_construct<typename cT::value_type, Rectangle>(rects[0]));
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return;
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}
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nodes.reserve(rects.size());
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for(std::size_t i = 0; i < rects.size(); ++i) { nodes.push_back(Node(rects[i])); }
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}
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computeDag(nodes.begin(), nodes.end(), orient, nodes.size());
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for(std::size_t i = 0; i < nodes.size(); ++i) {
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getMaxCover(outputContainer, &(nodes[i]), orient);
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}
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}
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};
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}
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}
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#endif
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