godot/core/sort.h
2017-07-08 22:24:56 +07:00

307 lines
8.5 KiB
C++

/*************************************************************************/
/* sort.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* http://www.godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2017 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_H
#define SORT_H
#include "typedefs.h"
/**
@author ,,, <red@lunatea>
*/
template <class T>
struct _DefaultComparator {
inline bool operator()(const T &a, const T &b) const { return (a < b); }
};
template <class T, class Comparator = _DefaultComparator<T> >
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 {
while (true) {
while (compare(p_array[p_first], p_pivot))
p_first++;
p_last--;
while (compare(p_pivot, p_array[p_last]))
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])) {
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