f8ab79e68a
This prevents the pitfall of UB when checking if they have been assigned something valid by comparing to nullptr.
704 lines
16 KiB
C++
704 lines
16 KiB
C++
/*************************************************************************/
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/* set.h */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md). */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#ifndef SET_H
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#define SET_H
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#include "core/os/memory.h"
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#include "core/typedefs.h"
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// based on the very nice implementation of rb-trees by:
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// https://web.archive.org/web/20120507164830/https://web.mit.edu/~emin/www/source_code/red_black_tree/index.html
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template <class T, class C = Comparator<T>, class A = DefaultAllocator>
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class Set {
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enum Color {
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RED,
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BLACK
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};
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struct _Data;
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public:
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class Element {
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private:
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friend class Set<T, C, A>;
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int color = RED;
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Element *right = nullptr;
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Element *left = nullptr;
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Element *parent = nullptr;
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Element *_next = nullptr;
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Element *_prev = nullptr;
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T value;
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//_Data *data;
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public:
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const Element *next() const {
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return _next;
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}
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Element *next() {
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return _next;
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}
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const Element *prev() const {
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return _prev;
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}
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Element *prev() {
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return _prev;
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}
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T &get() {
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return value;
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}
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const T &get() const {
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return value;
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};
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Element() {}
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};
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typedef T ValueType;
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struct Iterator {
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_FORCE_INLINE_ T &operator*() const {
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return E->get();
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}
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_FORCE_INLINE_ T *operator->() const { return &E->get(); }
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_FORCE_INLINE_ Iterator &operator++() {
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E = E->next();
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return *this;
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}
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_FORCE_INLINE_ Iterator &operator--() {
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E = E->prev();
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return *this;
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}
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_FORCE_INLINE_ bool operator==(const Iterator &b) const { return E == b.E; }
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_FORCE_INLINE_ bool operator!=(const Iterator &b) const { return E != b.E; }
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Iterator(Element *p_E) { E = p_E; }
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Iterator() {}
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Iterator(const Iterator &p_it) { E = p_it.E; }
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private:
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Element *E = nullptr;
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};
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struct ConstIterator {
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_FORCE_INLINE_ const T &operator*() const {
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return E->get();
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}
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_FORCE_INLINE_ const T *operator->() const { return &E->get(); }
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_FORCE_INLINE_ ConstIterator &operator++() {
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E = E->next();
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return *this;
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}
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_FORCE_INLINE_ ConstIterator &operator--() {
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E = E->prev();
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return *this;
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}
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_FORCE_INLINE_ bool operator==(const ConstIterator &b) const { return E == b.E; }
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_FORCE_INLINE_ bool operator!=(const ConstIterator &b) const { return E != b.E; }
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_FORCE_INLINE_ ConstIterator(const Element *p_E) { E = p_E; }
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_FORCE_INLINE_ ConstIterator() {}
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_FORCE_INLINE_ ConstIterator(const ConstIterator &p_it) { E = p_it.E; }
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private:
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const Element *E = nullptr;
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};
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_FORCE_INLINE_ Iterator begin() {
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return Iterator(front());
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}
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_FORCE_INLINE_ Iterator end() {
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return Iterator(nullptr);
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}
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#if 0
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//to use when replacing find()
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_FORCE_INLINE_ Iterator find(const K &p_key) {
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return Iterator(find(p_key));
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}
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#endif
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_FORCE_INLINE_ ConstIterator begin() const {
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return ConstIterator(front());
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}
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_FORCE_INLINE_ ConstIterator end() const {
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return ConstIterator(nullptr);
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}
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#if 0
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//to use when replacing find()
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_FORCE_INLINE_ ConstIterator find(const K &p_key) const {
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return ConstIterator(find(p_key));
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}
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#endif
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private:
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struct _Data {
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Element *_root = nullptr;
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Element *_nil = nullptr;
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int size_cache = 0;
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_FORCE_INLINE_ _Data() {
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#ifdef GLOBALNIL_DISABLED
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_nil = memnew_allocator(Element, A);
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_nil->parent = _nil->left = _nil->right = _nil;
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_nil->color = BLACK;
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#else
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_nil = (Element *)&_GlobalNilClass::_nil;
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#endif
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}
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void _create_root() {
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_root = memnew_allocator(Element, A);
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_root->parent = _root->left = _root->right = _nil;
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_root->color = BLACK;
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}
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void _free_root() {
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if (_root) {
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memdelete_allocator<Element, A>(_root);
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_root = nullptr;
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}
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}
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~_Data() {
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_free_root();
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#ifdef GLOBALNIL_DISABLED
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memdelete_allocator<Element, A>(_nil);
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#endif
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}
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};
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_Data _data;
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inline void _set_color(Element *p_node, int p_color) {
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ERR_FAIL_COND(p_node == _data._nil && p_color == RED);
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p_node->color = p_color;
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}
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inline void _rotate_left(Element *p_node) {
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Element *r = p_node->right;
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p_node->right = r->left;
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if (r->left != _data._nil) {
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r->left->parent = p_node;
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}
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r->parent = p_node->parent;
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if (p_node == p_node->parent->left) {
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p_node->parent->left = r;
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} else {
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p_node->parent->right = r;
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}
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r->left = p_node;
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p_node->parent = r;
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}
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inline void _rotate_right(Element *p_node) {
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Element *l = p_node->left;
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p_node->left = l->right;
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if (l->right != _data._nil) {
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l->right->parent = p_node;
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}
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l->parent = p_node->parent;
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if (p_node == p_node->parent->right) {
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p_node->parent->right = l;
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} else {
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p_node->parent->left = l;
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}
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l->right = p_node;
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p_node->parent = l;
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}
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inline Element *_successor(Element *p_node) const {
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Element *node = p_node;
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if (node->right != _data._nil) {
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node = node->right;
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while (node->left != _data._nil) { /* returns the minimum of the right subtree of node */
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node = node->left;
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}
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return node;
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} else {
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while (node == node->parent->right) {
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node = node->parent;
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}
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if (node->parent == _data._root) {
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return nullptr; // No successor, as p_node = last node
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}
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return node->parent;
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}
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}
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inline Element *_predecessor(Element *p_node) const {
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Element *node = p_node;
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if (node->left != _data._nil) {
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node = node->left;
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while (node->right != _data._nil) { /* returns the minimum of the left subtree of node */
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node = node->right;
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}
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return node;
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} else {
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while (node == node->parent->left) {
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node = node->parent;
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}
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if (node == _data._root) {
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return nullptr; // No predecessor, as p_node = first node.
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}
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return node->parent;
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}
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}
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Element *_find(const T &p_value) const {
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Element *node = _data._root->left;
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C less;
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while (node != _data._nil) {
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if (less(p_value, node->value)) {
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node = node->left;
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} else if (less(node->value, p_value)) {
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node = node->right;
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} else {
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return node; // found
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}
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}
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return nullptr;
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}
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Element *_lower_bound(const T &p_value) const {
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Element *node = _data._root->left;
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Element *prev = nullptr;
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C less;
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while (node != _data._nil) {
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prev = node;
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if (less(p_value, node->value)) {
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node = node->left;
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} else if (less(node->value, p_value)) {
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node = node->right;
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} else {
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return node; // found
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}
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}
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if (prev == nullptr) {
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return nullptr; // tree empty
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}
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if (less(prev->value, p_value)) {
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prev = prev->_next;
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}
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return prev;
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}
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void _insert_rb_fix(Element *p_new_node) {
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Element *node = p_new_node;
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Element *nparent = node->parent;
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Element *ngrand_parent = nullptr;
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while (nparent->color == RED) {
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ngrand_parent = nparent->parent;
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if (nparent == ngrand_parent->left) {
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if (ngrand_parent->right->color == RED) {
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_set_color(nparent, BLACK);
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_set_color(ngrand_parent->right, BLACK);
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_set_color(ngrand_parent, RED);
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node = ngrand_parent;
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nparent = node->parent;
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} else {
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if (node == nparent->right) {
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_rotate_left(nparent);
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node = nparent;
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nparent = node->parent;
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}
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_set_color(nparent, BLACK);
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_set_color(ngrand_parent, RED);
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_rotate_right(ngrand_parent);
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}
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} else {
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if (ngrand_parent->left->color == RED) {
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_set_color(nparent, BLACK);
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_set_color(ngrand_parent->left, BLACK);
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_set_color(ngrand_parent, RED);
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node = ngrand_parent;
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nparent = node->parent;
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} else {
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if (node == nparent->left) {
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_rotate_right(nparent);
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node = nparent;
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nparent = node->parent;
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}
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_set_color(nparent, BLACK);
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_set_color(ngrand_parent, RED);
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_rotate_left(ngrand_parent);
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}
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}
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}
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_set_color(_data._root->left, BLACK);
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}
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Element *_insert(const T &p_value) {
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Element *new_parent = _data._root;
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Element *node = _data._root->left;
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C less;
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while (node != _data._nil) {
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new_parent = node;
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if (less(p_value, node->value)) {
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node = node->left;
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} else if (less(node->value, p_value)) {
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node = node->right;
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} else {
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return node; // Return existing node
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}
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}
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Element *new_node = memnew_allocator(Element, A);
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new_node->parent = new_parent;
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new_node->right = _data._nil;
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new_node->left = _data._nil;
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new_node->value = p_value;
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//new_node->data=_data;
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if (new_parent == _data._root || less(p_value, new_parent->value)) {
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new_parent->left = new_node;
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} else {
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new_parent->right = new_node;
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}
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new_node->_next = _successor(new_node);
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new_node->_prev = _predecessor(new_node);
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if (new_node->_next) {
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new_node->_next->_prev = new_node;
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}
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if (new_node->_prev) {
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new_node->_prev->_next = new_node;
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}
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_data.size_cache++;
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_insert_rb_fix(new_node);
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return new_node;
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}
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void _erase_fix_rb(Element *p_node) {
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Element *root = _data._root->left;
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Element *node = _data._nil;
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Element *sibling = p_node;
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Element *parent = sibling->parent;
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while (node != root) { // If red node found, will exit at a break
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if (sibling->color == RED) {
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_set_color(sibling, BLACK);
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_set_color(parent, RED);
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if (sibling == parent->right) {
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sibling = sibling->left;
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_rotate_left(parent);
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} else {
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sibling = sibling->right;
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_rotate_right(parent);
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}
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}
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if ((sibling->left->color == BLACK) && (sibling->right->color == BLACK)) {
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_set_color(sibling, RED);
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if (parent->color == RED) {
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_set_color(parent, BLACK);
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break;
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} else { // loop: haven't found any red nodes yet
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node = parent;
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parent = node->parent;
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sibling = (node == parent->left) ? parent->right : parent->left;
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}
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} else {
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if (sibling == parent->right) {
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if (sibling->right->color == BLACK) {
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_set_color(sibling->left, BLACK);
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_set_color(sibling, RED);
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_rotate_right(sibling);
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sibling = sibling->parent;
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}
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_set_color(sibling, parent->color);
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_set_color(parent, BLACK);
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_set_color(sibling->right, BLACK);
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_rotate_left(parent);
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break;
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} else {
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if (sibling->left->color == BLACK) {
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_set_color(sibling->right, BLACK);
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_set_color(sibling, RED);
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_rotate_left(sibling);
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sibling = sibling->parent;
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}
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_set_color(sibling, parent->color);
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_set_color(parent, BLACK);
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_set_color(sibling->left, BLACK);
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_rotate_right(parent);
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break;
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}
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}
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}
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ERR_FAIL_COND(_data._nil->color != BLACK);
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}
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void _erase(Element *p_node) {
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Element *rp = ((p_node->left == _data._nil) || (p_node->right == _data._nil)) ? p_node : p_node->_next;
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Element *node = (rp->left == _data._nil) ? rp->right : rp->left;
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Element *sibling = nullptr;
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if (rp == rp->parent->left) {
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rp->parent->left = node;
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sibling = rp->parent->right;
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} else {
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rp->parent->right = node;
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sibling = rp->parent->left;
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}
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if (node->color == RED) {
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node->parent = rp->parent;
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_set_color(node, BLACK);
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} else if (rp->color == BLACK && rp->parent != _data._root) {
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_erase_fix_rb(sibling);
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}
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if (rp != p_node) {
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ERR_FAIL_COND(rp == _data._nil);
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rp->left = p_node->left;
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rp->right = p_node->right;
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rp->parent = p_node->parent;
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rp->color = p_node->color;
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if (p_node->left != _data._nil) {
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p_node->left->parent = rp;
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}
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if (p_node->right != _data._nil) {
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p_node->right->parent = rp;
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}
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if (p_node == p_node->parent->left) {
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p_node->parent->left = rp;
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} else {
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p_node->parent->right = rp;
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}
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}
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if (p_node->_next) {
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p_node->_next->_prev = p_node->_prev;
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}
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if (p_node->_prev) {
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p_node->_prev->_next = p_node->_next;
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}
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memdelete_allocator<Element, A>(p_node);
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_data.size_cache--;
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ERR_FAIL_COND(_data._nil->color == RED);
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}
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void _calculate_depth(Element *p_element, int &max_d, int d) const {
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if (p_element == _data._nil) {
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return;
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}
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_calculate_depth(p_element->left, max_d, d + 1);
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_calculate_depth(p_element->right, max_d, d + 1);
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if (d > max_d) {
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max_d = d;
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}
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}
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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 Set &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 Set &p_set) {
|
|
_copy_from(p_set);
|
|
}
|
|
|
|
Set(const Set &p_set) {
|
|
_copy_from(p_set);
|
|
}
|
|
|
|
_FORCE_INLINE_ Set() {}
|
|
|
|
~Set() {
|
|
clear();
|
|
}
|
|
};
|
|
|
|
#endif // SET_H
|