godot/core/templates/sort_array.h
Rémi Verschelde b5334d14f7
Update copyright statements to 2021
Happy new year to the wonderful Godot community!

2020 has been a tough year for most of us personally, but a good year for
Godot development nonetheless with a huge amount of work done towards Godot
4.0 and great improvements backported to the long-lived 3.2 branch.

We've had close to 400 contributors to engine code this year, authoring near
7,000 commit! (And that's only for the `master` branch and for the engine code,
there's a lot more when counting docs, demos and other first-party repos.)

Here's to a great year 2021 for all Godot users 🎆
2021-01-01 20:19:21 +01:00

321 lines
9.4 KiB
C++

/*************************************************************************/
/* sort_array.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2021 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 SORT_ARRAY_H
#define SORT_ARRAY_H
#include "core/error/error_macros.h"
#include "core/typedefs.h"
#define ERR_BAD_COMPARE(cond) \
if (unlikely(cond)) { \
ERR_PRINT("bad comparison function; sorting will be broken"); \
break; \
}
template <class T>
struct _DefaultComparator {
_FORCE_INLINE_ bool operator()(const T &a, const T &b) const { return (a < b); }
};
#ifdef DEBUG_ENABLED
#define SORT_ARRAY_VALIDATE_ENABLED true
#else
#define SORT_ARRAY_VALIDATE_ENABLED false
#endif
template <class T, class Comparator = _DefaultComparator<T>, bool Validate = SORT_ARRAY_VALIDATE_ENABLED>
class SortArray {
enum {
INTROSORT_THRESHOLD = 16
};
public:
Comparator compare;
inline const T &median_of_3(const T &a, const T &b, const T &c) const {
if (compare(a, b)) {
if (compare(b, c)) {
return b;
} else if (compare(a, c)) {
return c;
} else {
return a;
}
} else if (compare(a, c)) {
return a;
} else if (compare(b, c)) {
return c;
} else {
return b;
}
}
inline int bitlog(int n) const {
int k;
for (k = 0; n != 1; n >>= 1) {
++k;
}
return k;
}
/* Heap / Heapsort functions */
inline void push_heap(int p_first, int p_hole_idx, int p_top_index, T p_value, T *p_array) const {
int parent = (p_hole_idx - 1) / 2;
while (p_hole_idx > p_top_index && compare(p_array[p_first + parent], p_value)) {
p_array[p_first + p_hole_idx] = p_array[p_first + parent];
p_hole_idx = parent;
parent = (p_hole_idx - 1) / 2;
}
p_array[p_first + p_hole_idx] = p_value;
}
inline void pop_heap(int p_first, int p_last, int p_result, T p_value, T *p_array) const {
p_array[p_result] = p_array[p_first];
adjust_heap(p_first, 0, p_last - p_first, p_value, p_array);
}
inline void pop_heap(int p_first, int p_last, T *p_array) const {
pop_heap(p_first, p_last - 1, p_last - 1, p_array[p_last - 1], p_array);
}
inline void adjust_heap(int p_first, int p_hole_idx, int p_len, T p_value, T *p_array) const {
int top_index = p_hole_idx;
int second_child = 2 * p_hole_idx + 2;
while (second_child < p_len) {
if (compare(p_array[p_first + second_child], p_array[p_first + (second_child - 1)])) {
second_child--;
}
p_array[p_first + p_hole_idx] = p_array[p_first + second_child];
p_hole_idx = second_child;
second_child = 2 * (second_child + 1);
}
if (second_child == p_len) {
p_array[p_first + p_hole_idx] = p_array[p_first + (second_child - 1)];
p_hole_idx = second_child - 1;
}
push_heap(p_first, p_hole_idx, top_index, p_value, p_array);
}
inline void sort_heap(int p_first, int p_last, T *p_array) const {
while (p_last - p_first > 1) {
pop_heap(p_first, p_last--, p_array);
}
}
inline void make_heap(int p_first, int p_last, T *p_array) const {
if (p_last - p_first < 2) {
return;
}
int len = p_last - p_first;
int parent = (len - 2) / 2;
while (true) {
adjust_heap(p_first, parent, len, p_array[p_first + parent], p_array);
if (parent == 0) {
return;
}
parent--;
}
}
inline void partial_sort(int p_first, int p_last, int p_middle, T *p_array) const {
make_heap(p_first, p_middle, p_array);
for (int i = p_middle; i < p_last; i++) {
if (compare(p_array[i], p_array[p_first])) {
pop_heap(p_first, p_middle, i, p_array[i], p_array);
}
}
sort_heap(p_first, p_middle, p_array);
}
inline void partial_select(int p_first, int p_last, int p_middle, T *p_array) const {
make_heap(p_first, p_middle, p_array);
for (int i = p_middle; i < p_last; i++) {
if (compare(p_array[i], p_array[p_first])) {
pop_heap(p_first, p_middle, i, p_array[i], p_array);
}
}
}
inline int partitioner(int p_first, int p_last, T p_pivot, T *p_array) const {
const int unmodified_first = p_first;
const int unmodified_last = p_last;
while (true) {
while (compare(p_array[p_first], p_pivot)) {
if (Validate) {
ERR_BAD_COMPARE(p_first == unmodified_last - 1);
}
p_first++;
}
p_last--;
while (compare(p_pivot, p_array[p_last])) {
if (Validate) {
ERR_BAD_COMPARE(p_last == unmodified_first);
}
p_last--;
}
if (!(p_first < p_last)) {
return p_first;
}
SWAP(p_array[p_first], p_array[p_last]);
p_first++;
}
}
inline void introsort(int p_first, int p_last, T *p_array, int p_max_depth) const {
while (p_last - p_first > INTROSORT_THRESHOLD) {
if (p_max_depth == 0) {
partial_sort(p_first, p_last, p_last, p_array);
return;
}
p_max_depth--;
int cut = partitioner(
p_first,
p_last,
median_of_3(
p_array[p_first],
p_array[p_first + (p_last - p_first) / 2],
p_array[p_last - 1]),
p_array);
introsort(cut, p_last, p_array, p_max_depth);
p_last = cut;
}
}
inline void introselect(int p_first, int p_nth, int p_last, T *p_array, int p_max_depth) const {
while (p_last - p_first > 3) {
if (p_max_depth == 0) {
partial_select(p_first, p_nth + 1, p_last, p_array);
SWAP(p_first, p_nth);
return;
}
p_max_depth--;
int cut = partitioner(
p_first,
p_last,
median_of_3(
p_array[p_first],
p_array[p_first + (p_last - p_first) / 2],
p_array[p_last - 1]),
p_array);
if (cut <= p_nth) {
p_first = cut;
} else {
p_last = cut;
}
}
insertion_sort(p_first, p_last, p_array);
}
inline void unguarded_linear_insert(int p_last, T p_value, T *p_array) const {
int next = p_last - 1;
while (compare(p_value, p_array[next])) {
if (Validate) {
ERR_BAD_COMPARE(next == 0);
}
p_array[p_last] = p_array[next];
p_last = next;
next--;
}
p_array[p_last] = p_value;
}
inline void linear_insert(int p_first, int p_last, T *p_array) const {
T val = p_array[p_last];
if (compare(val, p_array[p_first])) {
for (int i = p_last; i > p_first; i--) {
p_array[i] = p_array[i - 1];
}
p_array[p_first] = val;
} else {
unguarded_linear_insert(p_last, val, p_array);
}
}
inline void insertion_sort(int p_first, int p_last, T *p_array) const {
if (p_first == p_last) {
return;
}
for (int i = p_first + 1; i != p_last; i++) {
linear_insert(p_first, i, p_array);
}
}
inline void unguarded_insertion_sort(int p_first, int p_last, T *p_array) const {
for (int i = p_first; i != p_last; i++) {
unguarded_linear_insert(i, p_array[i], p_array);
}
}
inline void final_insertion_sort(int p_first, int p_last, T *p_array) const {
if (p_last - p_first > INTROSORT_THRESHOLD) {
insertion_sort(p_first, p_first + INTROSORT_THRESHOLD, p_array);
unguarded_insertion_sort(p_first + INTROSORT_THRESHOLD, p_last, p_array);
} else {
insertion_sort(p_first, p_last, p_array);
}
}
inline void sort_range(int p_first, int p_last, T *p_array) const {
if (p_first != p_last) {
introsort(p_first, p_last, p_array, bitlog(p_last - p_first) * 2);
final_insertion_sort(p_first, p_last, p_array);
}
}
inline void sort(T *p_array, int p_len) const {
sort_range(0, p_len, p_array);
}
inline void nth_element(int p_first, int p_last, int p_nth, T *p_array) const {
if (p_first == p_last || p_nth == p_last) {
return;
}
introselect(p_first, p_nth, p_last, p_array, bitlog(p_last - p_first) * 2);
}
};
#endif // SORT_ARRAY_H