blob: d0db319d07505849066aa35896c8a6d0fbed75b6 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
|
// Copyright (C) 2002-2005 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h
#ifndef __IRR_HEAPSORT_H_INCLUDED__
#define __IRR_HEAPSORT_H_INCLUDED__
#include "irrTypes.h"
namespace irr
{
namespace core
{
//! Sinks an element into the heap.
template<class T>
inline void heapsink(T*array, s32 element, s32 max)
{
while ((element<<1) < max) // there is a left child
{
s32 j = (element<<1);
if (j+1 < max && array[j] < array[j+1])
j = j+1; // take right child
if (array[element] < array[j])
{
T t = array[j]; // swap elements
array[j] = array[element];
array[element] = t;
element = j;
}
else
return;
}
}
//! Sorts an array with size 'size' using heapsort.
template<class T>
inline void heapsort(T* array_, s32 size)
{
// for heapsink we pretent this is not c++, where
// arrays start with index 0. So we decrease the array pointer,
// the maximum always +2 and the element always +1
T* virtualArray = array_ - 1;
s32 virtualSize = size + 2;
s32 i;
// build heap
for (i=((size-1)/2); i>=0; --i)
heapsink(virtualArray, i+1, virtualSize-1);
// sort array
for (i=size-1; i>=0; --i)
{
T t = array_[0];
array_[0] = array_[i];
array_[i] = t;
heapsink(virtualArray, 1, i + 1);
}
}
} // end namespace core
} // end namespace irr
#endif
|
