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godot/core/sort.h
Rémi Verschelde d8223ffa75 Welcome in 2017, dear changelog reader! 
That year should bring the long-awaited OpenGL ES 3.0 compatible renderer
with state-of-the-art rendering techniques tuned to work as low as middle
end handheld devices - without compromising with the possibilities given
for higher end desktop games of course. Great times ahead for the Godot
community and the gamers that will play our games!

(cherry picked from commit c7bc44d5ad)
2017-01-12 19:15:30 +01:00

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8.3 KiB
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/*************************************************************************/
/* sort.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* http://www.godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 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 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_TRESHOLD=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_TRESHOLD ) {
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_TRESHOLD) {
insertion_sort(p_first,p_first+INTROSORT_TRESHOLD,p_array);
unguarded_insertion_sort(p_first+INTROSORT_TRESHOLD,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
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