virtualx-engine/core/set.h
Rémi Verschelde 16f6a5b139
One Copyright Update to rule them all
As many open source projects have started doing it, we're removing the
current year from the copyright notice, so that we don't need to bump
it every year.

It seems like only the first year of publication is technically
relevant for copyright notices, and even that seems to be something
that many companies stopped listing altogether (in a version controlled
codebase, the commits are a much better source of date of publication
than a hardcoded copyright statement).

We also now list Godot Engine contributors first as we're collectively
the current maintainers of the project, and we clarify that the
"exclusive" copyright of the co-founders covers the timespan before
opensourcing (their further contributions are included as part of Godot
Engine contributors).

Also fixed "cf." Frenchism - it's meant as "refer to / see".

Backported from #70885.
2023-01-10 15:32:59 +01:00

632 lines
14 KiB
C++

/**************************************************************************/
/* set.h */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* 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 SET_H
#define 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/http://web.mit.edu/~emin/www/source_code/red_black_tree/index.html
template <class T, class C = Comparator<T>, class A = DefaultAllocator>
class Set {
enum Color {
RED,
BLACK
};
struct _Data;
public:
class Element {
private:
friend class Set<T, C, A>;
int color;
Element *right;
Element *left;
Element *parent;
Element *_next;
Element *_prev;
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;
}
const T &get() const {
return value;
};
Element() {
color = RED;
right = nullptr;
left = nullptr;
parent = nullptr;
_next = nullptr;
_prev = nullptr;
};
};
private:
struct _Data {
Element *_root;
Element *_nil;
int size_cache;
_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
_root = nullptr;
size_cache = 0;
}
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;
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;
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 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 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