GEOS  3.11.0beta2
TemplateSTRtree.h
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4  * http://geos.osgeo.org
5  *
6  * Copyright (C) 2020-2021 Daniel Baston
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14 
15 #pragma once
16 
17 #include <geos/geom/Geometry.h>
18 #include <geos/index/SpatialIndex.h> // for inheritance
19 #include <geos/index/chain/MonotoneChain.h>
20 #include <geos/index/ItemVisitor.h>
21 #include <geos/util.h>
22 
23 #include <geos/index/strtree/TemplateSTRNode.h>
24 #include <geos/index/strtree/TemplateSTRNodePair.h>
25 #include <geos/index/strtree/TemplateSTRtreeDistance.h>
26 #include <geos/index/strtree/Interval.h>
27 
28 #include <vector>
29 #include <queue>
30 #include <mutex>
31 
32 namespace geos {
33 namespace index {
34 namespace strtree {
35 
56 template<typename ItemType, typename BoundsTraits>
58 public:
59  using Node = TemplateSTRNode<ItemType, BoundsTraits>;
60  using NodeList = std::vector<Node>;
61  using NodeListIterator = typename NodeList::iterator;
62  using BoundsType = typename BoundsTraits::BoundsType;
63 
64  class Iterator {
65  public:
66  using iterator_category = std::forward_iterator_tag;
67  using value_type = ItemType;
68  using difference_type = typename NodeList::const_iterator::difference_type;
69  using pointer = ItemType*;
70  using reference = ItemType&;
71 
72  Iterator(typename NodeList::const_iterator&& iter,
73  typename NodeList::const_iterator&& end) : m_iter(iter), m_end(end) {
74  skipDeleted();
75  }
76 
77  const ItemType& operator*() const {
78  return m_iter->getItem();
79  }
80 
81  Iterator& operator++() {
82  m_iter++;
83  skipDeleted();
84  return *this;
85  }
86 
87  friend bool operator==(const Iterator& a, const Iterator& b) {
88  return a.m_iter == b.m_iter;
89  }
90 
91  friend bool operator!=(const Iterator& a, const Iterator& b) {
92  return a.m_iter != b.m_iter;
93  }
94 
95  private:
96  void skipDeleted() {
97  while(m_iter != m_end && m_iter->isDeleted()) {
98  m_iter++;
99  }
100  }
101 
102  typename NodeList::const_iterator m_iter;
103  typename NodeList::const_iterator m_end;
104  };
105 
106  class Items {
107  public:
108  explicit Items(TemplateSTRtreeImpl& tree) : m_tree(tree) {}
109 
110  Iterator begin() {
111  return Iterator(m_tree.nodes.cbegin(),
112  std::next(m_tree.nodes.cbegin(), static_cast<long>(m_tree.numItems)));
113  }
114 
115  Iterator end() {
116  return Iterator(std::next(m_tree.nodes.cbegin(), static_cast<long>(m_tree.numItems)),
117  std::next(m_tree.nodes.cbegin(), static_cast<long>(m_tree.numItems)));
118  }
119  private:
120  TemplateSTRtreeImpl& m_tree;
121  };
122 
125 
130  explicit TemplateSTRtreeImpl(size_t p_nodeCapacity = 10) :
131  root(nullptr),
132  nodeCapacity(p_nodeCapacity),
133  numItems(0)
134  {}
135 
141  TemplateSTRtreeImpl(size_t p_nodeCapacity, size_t itemCapacity) :
142  root(nullptr),
143  nodeCapacity(p_nodeCapacity),
144  numItems(0) {
145  auto finalSize = treeSize(itemCapacity);
146  nodes.reserve(finalSize);
147  }
148 
153  root(other.root),
154  nodeCapacity(other.nodeCapacity),
155  numItems(other.numItems) {
156  nodes = other.nodes;
157  }
158 
159  TemplateSTRtreeImpl& operator=(TemplateSTRtreeImpl other)
160  {
161  root = other.root;
162  nodeCapacity = other.nodeCapacity;
163  numItems = other.numItems;
164  nodes = other.nodes;
165  return *this;
166  }
167 
171 
173  void insert(ItemType&& item) {
174  insert(BoundsTraits::fromItem(item), std::forward<ItemType>(item));
175  }
176 
178  void insert(const ItemType& item) {
179  insert(BoundsTraits::fromItem(item), item);
180  }
181 
183  void insert(const BoundsType& itemEnv, ItemType&& item) {
184  if (!BoundsTraits::isNull(itemEnv)) {
185  createLeafNode(std::forward<ItemType>(item), itemEnv);
186  }
187  }
188 
190  void insert(const BoundsType& itemEnv, const ItemType& item) {
191  if (!BoundsTraits::isNull(itemEnv)) {
192  createLeafNode(item, itemEnv);
193  }
194  }
195 
199 
201  template<typename ItemDistance>
202  std::pair<ItemType, ItemType> nearestNeighbour(ItemDistance& distance) {
203  return nearestNeighbour(*this, distance);
204  }
205 
207  template<typename ItemDistance>
208  std::pair<ItemType, ItemType> nearestNeighbour() {
209  ItemDistance id;
210  return nearestNeighbour(*this);
211  }
212 
214  template<typename ItemDistance>
215  std::pair<ItemType, ItemType> nearestNeighbour(TemplateSTRtreeImpl<ItemType, BoundsTraits> & other,
216  ItemDistance & distance) {
217  if (!getRoot() || !other.getRoot()) {
218  return { nullptr, nullptr };
219  }
220 
221  TemplateSTRtreeDistance<ItemType, BoundsTraits, ItemDistance> td(distance);
222  return td.nearestNeighbour(*root, *other.root);
223  }
224 
226  template<typename ItemDistance>
227  std::pair<ItemType, ItemType> nearestNeighbour(TemplateSTRtreeImpl<ItemType, BoundsTraits>& other) {
228  ItemDistance id;
229  return nearestNeighbour(other, id);
230  }
231 
232  template<typename ItemDistance>
233  ItemType nearestNeighbour(const BoundsType& env, const ItemType& item, ItemDistance& itemDist) {
234  build();
235 
236  if (getRoot() == nullptr) {
237  return nullptr;
238  }
239 
240  TemplateSTRNode<ItemType, BoundsTraits> bnd(item, env);
241  TemplateSTRNodePair<ItemType, BoundsTraits, ItemDistance> pair(*getRoot(), bnd, itemDist);
242 
243  TemplateSTRtreeDistance<ItemType, BoundsTraits, ItemDistance> td(itemDist);
244  return td.nearestNeighbour(pair).first;
245  }
246 
247  template<typename ItemDistance>
248  ItemType nearestNeighbour(const BoundsType& env, const ItemType& item) {
249  ItemDistance id;
250  return nearestNeighbour(env, item, id);
251  }
252 
256 
257  // Query the tree using the specified visitor. The visitor must be callable
258  // either with a single argument of `const ItemType&` or with the
259  // arguments `(const BoundsType&, const ItemType&).
260  // The visitor need not return a value, but if it does return a value,
261  // false values will be taken as a signal to stop the query.
262  template<typename Visitor>
263  void query(const BoundsType& queryEnv, Visitor &&visitor) {
264  if (!built()) {
265  build();
266  }
267 
268  if (root && root->boundsIntersect(queryEnv)) {
269  if (root->isLeaf()) {
270  visitLeaf(visitor, *root);
271  } else {
272  query(queryEnv, *root, visitor);
273  }
274  }
275  }
276 
277  // Query the tree and collect items in the provided vector.
278  void query(const BoundsType& queryEnv, std::vector<ItemType>& results) {
279  query(queryEnv, [&results](const ItemType& x) {
280  results.push_back(x);
281  });
282  }
283 
287  Items items() {
288  build();
289  return Items(*this);
290  }
291 
296  template<typename F>
297  void iterate(F&& func) {
298  auto n = built() ? numItems : nodes.size();
299  for (size_t i = 0; i < n; i++) {
300  func(nodes[i].getItem());
301  }
302  }
303 
307 
308  bool remove(const BoundsType& itemEnv, const ItemType& item) {
309  build();
310 
311  if (root == nullptr) {
312  return false;
313  }
314 
315  if (root->isLeaf()) {
316  if (!root->isDeleted() && root->getItem() == item) {
317  root->removeItem();
318  return true;
319  }
320  return false;
321  }
322 
323  return remove(itemEnv, *root, item);
324  }
325 
329 
331  bool built() const {
332  return root != nullptr;
333  }
334 
336  const Node* getRoot() {
337  build();
338  return root;
339  }
340 
342 
344  void build() {
345  std::lock_guard<std::mutex> lock(lock_);
346 
347  if (built()) {
348  return;
349  }
350 
351  if (nodes.empty()) {
352  return;
353  }
354 
355  numItems = nodes.size();
356 
357  // compute final size of tree and set it aside in a single
358  // block of memory
359  auto finalSize = treeSize(numItems);
360  nodes.reserve(finalSize);
361 
362  // begin and end define a range of nodes needing parents
363  auto begin = nodes.begin();
364  auto number = static_cast<size_t>(std::distance(begin, nodes.end()));
365 
366  while (number > 1) {
367  createParentNodes(begin, number);
368  std::advance(begin, static_cast<long>(number)); // parents just added become children in the next round
369  number = static_cast<size_t>(std::distance(begin, nodes.end()));
370  }
371 
372  assert(finalSize == nodes.size());
373 
374  root = &nodes.back();
375  }
376 
377 protected:
378  std::mutex lock_;
379  NodeList nodes; //**< a list of all leaf and branch nodes in the tree. */
380  Node* root; //**< a pointer to the root node, if the tree has been built. */
381  size_t nodeCapacity; //*< maximum number of children of each node */
382  size_t numItems; //*< total number of items in the tree, if it has been built. */
383 
384  // Prevent instantiation of base class.
385  // ~TemplateSTRtreeImpl() = default;
386 
387  void createLeafNode(ItemType&& item, const BoundsType& env) {
388  nodes.emplace_back(std::forward<ItemType>(item), env);
389  }
390 
391  void createLeafNode(const ItemType& item, const BoundsType& env) {
392  nodes.emplace_back(item, env);
393  }
394 
395  void createBranchNode(const Node *begin, const Node *end) {
396  assert(nodes.size() < nodes.capacity());
397  nodes.emplace_back(begin, end);
398  }
399 
400  // calculate what the tree size will be when it is build. This is simply
401  // a version of createParentNodes that doesn't actually create anything.
402  size_t treeSize(size_t numLeafNodes) {
403  size_t nodesInTree = numLeafNodes;
404 
405  size_t nodesWithoutParents = numLeafNodes;
406  while (nodesWithoutParents > 1) {
407  auto numSlices = sliceCount(nodesWithoutParents);
408  auto nodesPerSlice = sliceCapacity(nodesWithoutParents, numSlices);
409 
410  size_t parentNodesAdded = 0;
411  for (size_t j = 0; j < numSlices; j++) {
412  auto nodesInSlice = std::min(nodesWithoutParents, nodesPerSlice);
413  nodesWithoutParents -= nodesInSlice;
414 
415  parentNodesAdded += static_cast<size_t>(std::ceil(
416  static_cast<double>(nodesInSlice) / static_cast<double>(nodeCapacity)));
417  }
418 
419  nodesInTree += parentNodesAdded;
420  nodesWithoutParents = parentNodesAdded;
421  }
422 
423  return nodesInTree;
424  }
425 
426  void createParentNodes(const NodeListIterator& begin, size_t number) {
427  // Arrange child nodes in two dimensions.
428  // First, divide them into vertical slices of a given size (left-to-right)
429  // Then create nodes within those slices (bottom-to-top)
430  auto numSlices = sliceCount(number);
431  std::size_t nodesPerSlice = sliceCapacity(number, numSlices);
432 
433  // We could sort all of the nodes here, but we don't actually need them to be
434  // completely sorted. They need to be sorted enough for each node to end up
435  // in the right vertical slice, but their relative position within the slice
436  // doesn't matter. So we do a partial sort for each slice below instead.
437  auto end = begin + static_cast<long>(number);
438  sortNodesX(begin, end);
439 
440  auto startOfSlice = begin;
441  for (decltype(numSlices) j = 0; j < numSlices; j++) {
442  // end iterator is being invalidated at each iteration
443  end = begin + static_cast<long>(number);
444  auto nodesRemaining = static_cast<size_t>(std::distance(startOfSlice, end));
445  auto nodesInSlice = std::min(nodesRemaining, nodesPerSlice);
446  auto endOfSlice = std::next(startOfSlice, static_cast<long>(nodesInSlice));
447 
448  // Make sure that every node that should be in this slice ends up somewhere
449  // between startOfSlice and endOfSlice. We don't require any ordering among
450  // nodes between startOfSlice and endOfSlice.
451  //partialSortNodes(startOfSlice, endOfSlice, end);
452 
453  addParentNodesFromVerticalSlice(startOfSlice, endOfSlice);
454 
455  startOfSlice = endOfSlice;
456  }
457  }
458 
459  void addParentNodesFromVerticalSlice(const NodeListIterator& begin, const NodeListIterator& end) {
460  if (BoundsTraits::TwoDimensional::value) {
461  sortNodesY(begin, end);
462  }
463 
464  // Arrange the nodes vertically and full up parent nodes sequentially until they're full.
465  // A possible improvement would be to rework this such so that if we have 81 nodes we
466  // put 9 into each parent instead of 10 or 1.
467  auto firstChild = begin;
468  while (firstChild != end) {
469  auto childrenRemaining = static_cast<size_t>(std::distance(firstChild, end));
470  auto childrenForNode = std::min(nodeCapacity, childrenRemaining);
471  auto lastChild = std::next(firstChild, static_cast<long>(childrenForNode));
472 
473  //partialSortNodes(firstChild, lastChild, end);
474 
475  // Ideally we would be able to store firstChild and lastChild instead of
476  // having to convert them to pointers, but I wasn't sure how to access
477  // the NodeListIterator type from within Node without creating some weird
478  // circular dependency.
479  const Node *ptr_first = &*firstChild;
480  const Node *ptr_end = ptr_first + childrenForNode;
481 
482  createBranchNode(ptr_first, ptr_end);
483  firstChild = lastChild;
484  }
485  }
486 
487  void sortNodesX(const NodeListIterator& begin, const NodeListIterator& end) {
488  std::sort(begin, end, [](const Node &a, const Node &b) {
489  return BoundsTraits::getX(a.getBounds()) < BoundsTraits::getX(b.getBounds());
490  });
491  }
492 
493  void sortNodesY(const NodeListIterator& begin, const NodeListIterator& end) {
494  std::sort(begin, end, [](const Node &a, const Node &b) {
495  return BoundsTraits::getY(a.getBounds()) < BoundsTraits::getY(b.getBounds());
496  });
497  }
498 
499  // Helper function to visit an item using a visitor that has no return value.
500  // In this case, we will always return true, indicating that querying should
501  // continue.
502  template<typename Visitor,
503  typename std::enable_if<std::is_void<decltype(std::declval<Visitor>()(std::declval<ItemType>()))>::value, std::nullptr_t>::type = nullptr >
504  bool visitLeaf(Visitor&& visitor, const Node& node)
505  {
506  visitor(node.getItem());
507  return true;
508  }
509 
510  // MSVC 2015 does not implement C++11 expression SFINAE and considers this a
511  // redefinition of a previous method
512 #if !defined(_MSC_VER) || _MSC_VER >= 1910
513  template<typename Visitor,
514  typename std::enable_if<std::is_void<decltype(std::declval<Visitor>()(std::declval<BoundsType>(), std::declval<ItemType>()))>::value, std::nullptr_t>::type = nullptr >
515  bool visitLeaf(Visitor&& visitor, const Node& node)
516  {
517  visitor(node.getBounds(), node.getItem());
518  return true;
519  }
520 #endif
521 
522  // If the visitor function does return a value, we will use this to indicate
523  // that querying should continue.
524  template<typename Visitor,
525  typename std::enable_if<!std::is_void<decltype(std::declval<Visitor>()(std::declval<ItemType>()))>::value, std::nullptr_t>::type = nullptr>
526  bool visitLeaf(Visitor&& visitor, const Node& node)
527  {
528  return visitor(node.getItem());
529  }
530 
531  // MSVC 2015 does not implement C++11 expression SFINAE and considers this a
532  // redefinition of a previous method
533 #if !defined(_MSC_VER) || _MSC_VER >= 1910
534  template<typename Visitor,
535  typename std::enable_if<!std::is_void<decltype(std::declval<Visitor>()(std::declval<BoundsType>(), std::declval<ItemType>()))>::value, std::nullptr_t>::type = nullptr>
536  bool visitLeaf(Visitor&& visitor, const Node& node)
537  {
538  return visitor(node.getBounds(), node.getItem());
539  }
540 #endif
541 
542  template<typename Visitor>
543  bool query(const BoundsType& queryEnv,
544  const Node& node,
545  Visitor&& visitor) {
546 
547  assert(!node.isLeaf());
548 
549  for (auto *child = node.beginChildren(); child < node.endChildren(); ++child) {
550  if (child->boundsIntersect(queryEnv)) {
551  if (child->isLeaf()) {
552  if (!child->isDeleted()) {
553  if (!visitLeaf(visitor, *child)) {
554  return false; // abort query
555  }
556  }
557  } else {
558  if (!query(queryEnv, *child, visitor)) {
559  return false; // abort query
560  }
561  }
562  }
563  }
564  return true; // continue searching
565  }
566 
567  bool remove(const BoundsType& queryEnv,
568  const Node& node,
569  const ItemType& item) {
570 
571  assert(!node.isLeaf());
572 
573  for (auto *child = node.beginChildren(); child < node.endChildren(); ++child) {
574  if (child->boundsIntersect(queryEnv)) {
575  if (child->isLeaf()) {
576  if (!child->isDeleted() && child->getItem() == item) {
577  // const cast is ugly, but alternative seems to be to remove all
578  // const qualifiers in Node and open up mutability everywhere?
579  auto mutableChild = const_cast<Node*>(child);
580  mutableChild->removeItem();
581  return true;
582  }
583  } else {
584  bool removed = remove(queryEnv, *child, item);
585  if (removed) {
586  return true;
587  }
588  }
589  }
590  }
591 
592  return false;
593  }
594 
595  size_t sliceCount(size_t numNodes) const {
596  double minLeafCount = std::ceil(static_cast<double>(numNodes) / static_cast<double>(nodeCapacity));
597 
598  return static_cast<size_t>(std::ceil(std::sqrt(minLeafCount)));
599  }
600 
601  static size_t sliceCapacity(size_t numNodes, size_t numSlices) {
602  return static_cast<size_t>(std::ceil(static_cast<double>(numNodes) / static_cast<double>(numSlices)));
603  }
604 };
605 
606 struct EnvelopeTraits {
607  using BoundsType = geom::Envelope;
608  using TwoDimensional = std::true_type;
609 
610  static bool intersects(const BoundsType& a, const BoundsType& b) {
611  return a.intersects(b);
612  }
613 
614  static double size(const BoundsType& a) {
615  return a.getArea();
616  }
617 
618  static double distance(const BoundsType& a, const BoundsType& b) {
619  return a.distance(b);
620  }
621 
622  static BoundsType empty() {
623  return {};
624  }
625 
626  template<typename ItemType>
627  static const BoundsType& fromItem(const ItemType& i) {
628  return *(i->getEnvelopeInternal());
629  }
630 
631  template<typename ItemType>
632  static const BoundsType& fromItem(ItemType&& i) {
633  return *(i->getEnvelopeInternal());
634  }
635 
636  static double getX(const BoundsType& a) {
637  return a.getMinX() + a.getMaxX();
638  }
639 
640  static double getY(const BoundsType& a) {
641  return a.getMinY() + a.getMaxY();
642  }
643 
644  static void expandToInclude(BoundsType& a, const BoundsType& b) {
645  a.expandToInclude(b);
646  }
647 
648  static bool isNull(const BoundsType& a) {
649  return a.isNull();
650  }
651 };
652 
653 struct IntervalTraits {
654  using BoundsType = Interval;
655  using TwoDimensional = std::false_type;
656 
657  static bool intersects(const BoundsType& a, const BoundsType& b) {
658  return a.intersects(&b);
659  }
660 
661  static double size(const BoundsType& a) {
662  return a.getWidth();
663  }
664 
665  static double getX(const BoundsType& a) {
666  return a.getMin() + a.getMax();
667  }
668 
669  static double getY(const BoundsType& a) {
670  return a.getMin() + a.getMax();
671  }
672 
673  static void expandToInclude(BoundsType& a, const BoundsType& b) {
674  a.expandToInclude(&b);
675  }
676 
677  static bool isNull(const BoundsType& a) {
678  (void) a;
679  return false;
680  }
681 };
682 
683 
684 template<typename ItemType, typename BoundsTraits = EnvelopeTraits>
685 class TemplateSTRtree : public TemplateSTRtreeImpl<ItemType, BoundsTraits> {
686 public:
688 };
689 
690 // When ItemType is a pointer and our bounds are geom::Envelope, adopt
691 // the SpatialIndex interface which requires queries via an envelope
692 // and items to be representable as void*.
693 template<typename ItemType>
694 class TemplateSTRtree<ItemType*, EnvelopeTraits> : public TemplateSTRtreeImpl<ItemType*, EnvelopeTraits>, public SpatialIndex {
695 public:
698  using TemplateSTRtreeImpl<ItemType*, EnvelopeTraits>::query;
699  using TemplateSTRtreeImpl<ItemType*, EnvelopeTraits>::remove;
700 
701  // The SpatialIndex methods only work when we are storing a pointer type.
702  void query(const geom::Envelope* queryEnv, std::vector<void*>& results) override {
703  query(*queryEnv, [&results](const ItemType* x) {
704  results.push_back(const_cast<void*>(static_cast<const void*>(x)));
705  });
706  }
707 
708  void query(const geom::Envelope* queryEnv, ItemVisitor& visitor) override {
709  query(*queryEnv, [&visitor](const ItemType* x) {
710  visitor.visitItem(const_cast<void*>(static_cast<const void*>(x)));
711  });
712  }
713 
714  bool remove(const geom::Envelope* itemEnv, void* item) override {
715  return remove(*itemEnv, static_cast<ItemType*>(item));
716  }
717 
718  void insert(const geom::Envelope* itemEnv, void* item) override {
719  insert(*itemEnv, std::move(static_cast<ItemType*>(item)));
720  }
721 };
722 
723 
724 }
725 }
726 }
A function method which computes the distance between two ItemBoundables in an STRtree....
Definition: ItemDistance.h:33
A query-only R-tree created using the Sort-Tile-Recursive (STR) algorithm. For one- or two-dimensiona...
Definition: TemplateSTRtree.h:57
void build()
Definition: TemplateSTRtree.h:344
std::pair< ItemType, ItemType > nearestNeighbour(TemplateSTRtreeImpl< ItemType, BoundsTraits > &other)
Definition: TemplateSTRtree.h:227
std::pair< ItemType, ItemType > nearestNeighbour(ItemDistance &distance)
Definition: TemplateSTRtree.h:202
std::pair< ItemType, ItemType > nearestNeighbour(TemplateSTRtreeImpl< ItemType, BoundsTraits > &other, ItemDistance &distance)
Definition: TemplateSTRtree.h:215
std::pair< ItemType, ItemType > nearestNeighbour()
Definition: TemplateSTRtree.h:208
TemplateSTRtreeImpl(size_t p_nodeCapacity=10)
Definition: TemplateSTRtree.h:130
TemplateSTRtreeImpl(size_t p_nodeCapacity, size_t itemCapacity)
Definition: TemplateSTRtree.h:141
TemplateSTRtreeImpl(const TemplateSTRtreeImpl &other)
Definition: TemplateSTRtree.h:152
void insert(const BoundsType &itemEnv, const ItemType &item)
Definition: TemplateSTRtree.h:190
void insert(const ItemType &item)
Definition: TemplateSTRtree.h:178
void insert(ItemType &&item)
Definition: TemplateSTRtree.h:173
void insert(const BoundsType &itemEnv, ItemType &&item)
Definition: TemplateSTRtree.h:183
const Node * getRoot()
Definition: TemplateSTRtree.h:336
bool built() const
Definition: TemplateSTRtree.h:331
void iterate(F &&func)
Definition: TemplateSTRtree.h:297
Items items()
Definition: TemplateSTRtree.h:287
Basic namespace for all GEOS functionalities.
Definition: Angle.h:25