/*************************************************************************/ /* rb_set.h */ /*************************************************************************/ /* This file is part of: */ /* GODOT ENGINE */ /* https://godotengine.org */ /*************************************************************************/ /* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur. */ /* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md). */ /* */ /* 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 RB_SET_H #define RB_SET_H #include "core/os/memory.h" #include "core/typedefs.h" // based on the very nice implementation of rb-trees by: // https://web.archive.org/web/20120507164830/https://web.mit.edu/~emin/www/source_code/red_black_tree/index.html template <class T, class C = Comparator<T>, class A = DefaultAllocator> class RBSet { enum Color { RED, BLACK }; struct _Data; public: class Element { private: friend class RBSet<T, C, A>; int color = RED; Element *right = nullptr; Element *left = nullptr; Element *parent = nullptr; Element *_next = nullptr; Element *_prev = nullptr; T value; //_Data *data; public: const Element *next() const { return _next; } Element *next() { return _next; } const Element *prev() const { return _prev; } Element *prev() { return _prev; } T &get() { return value; } const T &get() const { return value; }; Element() {} }; typedef T ValueType; struct Iterator { _FORCE_INLINE_ T &operator*() const { return E->get(); } _FORCE_INLINE_ T *operator->() const { return &E->get(); } _FORCE_INLINE_ Iterator &operator++() { E = E->next(); return *this; } _FORCE_INLINE_ Iterator &operator--() { E = E->prev(); return *this; } _FORCE_INLINE_ bool operator==(const Iterator &b) const { return E == b.E; } _FORCE_INLINE_ bool operator!=(const Iterator &b) const { return E != b.E; } explicit operator bool() const { return E != nullptr; } Iterator(Element *p_E) { E = p_E; } Iterator() {} Iterator(const Iterator &p_it) { E = p_it.E; } private: Element *E = nullptr; }; struct ConstIterator { _FORCE_INLINE_ const T &operator*() const { return E->get(); } _FORCE_INLINE_ const T *operator->() const { return &E->get(); } _FORCE_INLINE_ ConstIterator &operator++() { E = E->next(); return *this; } _FORCE_INLINE_ ConstIterator &operator--() { E = E->prev(); return *this; } _FORCE_INLINE_ bool operator==(const ConstIterator &b) const { return E == b.E; } _FORCE_INLINE_ bool operator!=(const ConstIterator &b) const { return E != b.E; } _FORCE_INLINE_ ConstIterator(const Element *p_E) { E = p_E; } _FORCE_INLINE_ ConstIterator() {} _FORCE_INLINE_ ConstIterator(const ConstIterator &p_it) { E = p_it.E; } explicit operator bool() const { return E != nullptr; } private: const Element *E = nullptr; }; _FORCE_INLINE_ Iterator begin() { return Iterator(front()); } _FORCE_INLINE_ Iterator end() { return Iterator(nullptr); } #if 0 //to use when replacing find() _FORCE_INLINE_ Iterator find(const K &p_key) { return Iterator(find(p_key)); } #endif _FORCE_INLINE_ ConstIterator begin() const { return ConstIterator(front()); } _FORCE_INLINE_ ConstIterator end() const { return ConstIterator(nullptr); } #if 0 //to use when replacing find() _FORCE_INLINE_ ConstIterator find(const K &p_key) const { return ConstIterator(find(p_key)); } #endif private: struct _Data { Element *_root = nullptr; Element *_nil = nullptr; int size_cache = 0; _FORCE_INLINE_ _Data() { #ifdef GLOBALNIL_DISABLED _nil = memnew_allocator(Element, A); _nil->parent = _nil->left = _nil->right = _nil; _nil->color = BLACK; #else _nil = (Element *)&_GlobalNilClass::_nil; #endif } void _create_root() { _root = memnew_allocator(Element, A); _root->parent = _root->left = _root->right = _nil; _root->color = BLACK; } void _free_root() { if (_root) { memdelete_allocator<Element, A>(_root); _root = nullptr; } } ~_Data() { _free_root(); #ifdef GLOBALNIL_DISABLED memdelete_allocator<Element, A>(_nil); #endif } }; _Data _data; inline void _set_color(Element *p_node, int p_color) { ERR_FAIL_COND(p_node == _data._nil && p_color == RED); p_node->color = p_color; } inline void _rotate_left(Element *p_node) { Element *r = p_node->right; p_node->right = r->left; if (r->left != _data._nil) { r->left->parent = p_node; } r->parent = p_node->parent; if (p_node == p_node->parent->left) { p_node->parent->left = r; } else { p_node->parent->right = r; } r->left = p_node; p_node->parent = r; } inline void _rotate_right(Element *p_node) { Element *l = p_node->left; p_node->left = l->right; if (l->right != _data._nil) { l->right->parent = p_node; } l->parent = p_node->parent; if (p_node == p_node->parent->right) { p_node->parent->right = l; } else { p_node->parent->left = l; } l->right = p_node; p_node->parent = l; } inline Element *_successor(Element *p_node) const { Element *node = p_node; if (node->right != _data._nil) { node = node->right; while (node->left != _data._nil) { /* returns the minimum of the right subtree of node */ node = node->left; } return node; } else { while (node == node->parent->right) { node = node->parent; } if (node->parent == _data._root) { return nullptr; // No successor, as p_node = last node } return node->parent; } } inline Element *_predecessor(Element *p_node) const { Element *node = p_node; if (node->left != _data._nil) { node = node->left; while (node->right != _data._nil) { /* returns the minimum of the left subtree of node */ node = node->right; } return node; } else { while (node == node->parent->left) { node = node->parent; } if (node == _data._root) { return nullptr; // No predecessor, as p_node = first node. } return node->parent; } } Element *_find(const T &p_value) const { Element *node = _data._root->left; C less; while (node != _data._nil) { if (less(p_value, node->value)) { node = node->left; } else if (less(node->value, p_value)) { node = node->right; } else { return node; // found } } return nullptr; } Element *_lower_bound(const T &p_value) const { Element *node = _data._root->left; Element *prev = nullptr; C less; while (node != _data._nil) { prev = node; if (less(p_value, node->value)) { node = node->left; } else if (less(node->value, p_value)) { node = node->right; } else { return node; // found } } if (prev == nullptr) { return nullptr; // tree empty } if (less(prev->value, p_value)) { prev = prev->_next; } return prev; } void _insert_rb_fix(Element *p_new_node) { Element *node = p_new_node; Element *nparent = node->parent; Element *ngrand_parent = nullptr; while (nparent->color == RED) { ngrand_parent = nparent->parent; if (nparent == ngrand_parent->left) { if (ngrand_parent->right->color == RED) { _set_color(nparent, BLACK); _set_color(ngrand_parent->right, BLACK); _set_color(ngrand_parent, RED); node = ngrand_parent; nparent = node->parent; } else { if (node == nparent->right) { _rotate_left(nparent); node = nparent; nparent = node->parent; } _set_color(nparent, BLACK); _set_color(ngrand_parent, RED); _rotate_right(ngrand_parent); } } else { if (ngrand_parent->left->color == RED) { _set_color(nparent, BLACK); _set_color(ngrand_parent->left, BLACK); _set_color(ngrand_parent, RED); node = ngrand_parent; nparent = node->parent; } else { if (node == nparent->left) { _rotate_right(nparent); node = nparent; nparent = node->parent; } _set_color(nparent, BLACK); _set_color(ngrand_parent, RED); _rotate_left(ngrand_parent); } } } _set_color(_data._root->left, BLACK); } Element *_insert(const T &p_value) { Element *new_parent = _data._root; Element *node = _data._root->left; C less; while (node != _data._nil) { new_parent = node; if (less(p_value, node->value)) { node = node->left; } else if (less(node->value, p_value)) { node = node->right; } else { return node; // Return existing node } } Element *new_node = memnew_allocator(Element, A); new_node->parent = new_parent; new_node->right = _data._nil; new_node->left = _data._nil; new_node->value = p_value; //new_node->data=_data; if (new_parent == _data._root || less(p_value, new_parent->value)) { new_parent->left = new_node; } else { new_parent->right = new_node; } new_node->_next = _successor(new_node); new_node->_prev = _predecessor(new_node); if (new_node->_next) { new_node->_next->_prev = new_node; } if (new_node->_prev) { new_node->_prev->_next = new_node; } _data.size_cache++; _insert_rb_fix(new_node); return new_node; } void _erase_fix_rb(Element *p_node) { Element *root = _data._root->left; Element *node = _data._nil; Element *sibling = p_node; Element *parent = sibling->parent; while (node != root) { // If red node found, will exit at a break if (sibling->color == RED) { _set_color(sibling, BLACK); _set_color(parent, RED); if (sibling == parent->right) { sibling = sibling->left; _rotate_left(parent); } else { sibling = sibling->right; _rotate_right(parent); } } if ((sibling->left->color == BLACK) && (sibling->right->color == BLACK)) { _set_color(sibling, RED); if (parent->color == RED) { _set_color(parent, BLACK); break; } else { // loop: haven't found any red nodes yet node = parent; parent = node->parent; sibling = (node == parent->left) ? parent->right : parent->left; } } else { if (sibling == parent->right) { if (sibling->right->color == BLACK) { _set_color(sibling->left, BLACK); _set_color(sibling, RED); _rotate_right(sibling); sibling = sibling->parent; } _set_color(sibling, parent->color); _set_color(parent, BLACK); _set_color(sibling->right, BLACK); _rotate_left(parent); break; } else { if (sibling->left->color == BLACK) { _set_color(sibling->right, BLACK); _set_color(sibling, RED); _rotate_left(sibling); sibling = sibling->parent; } _set_color(sibling, parent->color); _set_color(parent, BLACK); _set_color(sibling->left, BLACK); _rotate_right(parent); break; } } } ERR_FAIL_COND(_data._nil->color != BLACK); } void _erase(Element *p_node) { Element *rp = ((p_node->left == _data._nil) || (p_node->right == _data._nil)) ? p_node : p_node->_next; Element *node = (rp->left == _data._nil) ? rp->right : rp->left; Element *sibling = nullptr; if (rp == rp->parent->left) { rp->parent->left = node; sibling = rp->parent->right; } else { rp->parent->right = node; sibling = rp->parent->left; } if (node->color == RED) { node->parent = rp->parent; _set_color(node, BLACK); } else if (rp->color == BLACK && rp->parent != _data._root) { _erase_fix_rb(sibling); } if (rp != p_node) { ERR_FAIL_COND(rp == _data._nil); rp->left = p_node->left; rp->right = p_node->right; rp->parent = p_node->parent; rp->color = p_node->color; if (p_node->left != _data._nil) { p_node->left->parent = rp; } if (p_node->right != _data._nil) { p_node->right->parent = rp; } if (p_node == p_node->parent->left) { p_node->parent->left = rp; } else { p_node->parent->right = rp; } } if (p_node->_next) { p_node->_next->_prev = p_node->_prev; } if (p_node->_prev) { p_node->_prev->_next = p_node->_next; } memdelete_allocator<Element, A>(p_node); _data.size_cache--; ERR_FAIL_COND(_data._nil->color == RED); } void _calculate_depth(Element *p_element, int &max_d, int d) const { if (p_element == _data._nil) { return; } _calculate_depth(p_element->left, max_d, d + 1); _calculate_depth(p_element->right, max_d, d + 1); if (d > max_d) { max_d = d; } } void _cleanup_tree(Element *p_element) { if (p_element == _data._nil) { return; } _cleanup_tree(p_element->left); _cleanup_tree(p_element->right); memdelete_allocator<Element, A>(p_element); } void _copy_from(const RBSet &p_set) { clear(); // not the fastest way, but safeset to write. for (Element *I = p_set.front(); I; I = I->next()) { insert(I->get()); } } public: const Element *find(const T &p_value) const { if (!_data._root) { return nullptr; } const Element *res = _find(p_value); return res; } Element *find(const T &p_value) { if (!_data._root) { return nullptr; } Element *res = _find(p_value); return res; } Element *lower_bound(const T &p_value) const { if (!_data._root) { return nullptr; } return _lower_bound(p_value); } bool has(const T &p_value) const { return find(p_value) != nullptr; } Element *insert(const T &p_value) { if (!_data._root) { _data._create_root(); } return _insert(p_value); } void erase(Element *p_element) { if (!_data._root || !p_element) { return; } _erase(p_element); if (_data.size_cache == 0 && _data._root) { _data._free_root(); } } bool erase(const T &p_value) { if (!_data._root) { return false; } Element *e = find(p_value); if (!e) { return false; } _erase(e); if (_data.size_cache == 0 && _data._root) { _data._free_root(); } return true; } Element *front() const { if (!_data._root) { return nullptr; } Element *e = _data._root->left; if (e == _data._nil) { return nullptr; } while (e->left != _data._nil) { e = e->left; } return e; } Element *back() const { if (!_data._root) { return nullptr; } Element *e = _data._root->left; if (e == _data._nil) { return nullptr; } while (e->right != _data._nil) { e = e->right; } return e; } inline bool is_empty() const { return _data.size_cache == 0; } inline int size() const { return _data.size_cache; } int calculate_depth() const { // used for debug mostly if (!_data._root) { return 0; } int max_d = 0; _calculate_depth(_data._root->left, max_d, 0); return max_d; } void clear() { if (!_data._root) { return; } _cleanup_tree(_data._root->left); _data._root->left = _data._nil; _data.size_cache = 0; _data._free_root(); } void operator=(const RBSet &p_set) { _copy_from(p_set); } RBSet(const RBSet &p_set) { _copy_from(p_set); } _FORCE_INLINE_ RBSet() {} ~RBSet() { clear(); } }; #endif // RB_SET_H