irrlicht/include/heapsort.h
cutealien bff1a50c34 Minor code cleanup
Mostly const fixes in headers to make it easier for users to have more warnings enabled in static code analysis
Also updating our own rules a bit (kicking some out we won't need yet).

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6583 dfc29bdd-3216-0410-991c-e03cc46cb475
2024-01-01 15:29:28 +00:00

70 lines
1.5 KiB
C++

// Copyright (C) 2002-2012 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 pretend 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;
const s32 virtualSize = size + 2;
// build heap
for (s32 i=((size-1)/2); i>=0; --i)
heapsink(virtualArray, i+1, virtualSize-1);
// sort array, leave out the last element (0)
for (s32 i=size-1; i>0; --i)
{
const T t = array_[0];
array_[0] = array_[i];
array_[i] = t;
heapsink(virtualArray, 1, i + 1);
}
}
} // end namespace core
} // end namespace irr
#endif