void quicksort(int leftIn, int rightIn, IntComparator compare, RandomSeed seed) {
if (leftIn >= rightIn) return;
int left = leftIn;
int right = rightIn;
while (true) // tail recursion loop
{
if (right - left < 9) {
insertionsort(left, right + 1, compare);
return;
}
// Select random index for the pivot
seed.random = NumberUtils.nextRand(seed.random);
long nom = ((long) (right - left)) * seed.random;
int pivotIndex = (int) (nom / NumberUtils.intMax()) + left;
// Get the pivot value
int pivotValue = m_buffer[pivotIndex];
// Start partition
// Move pivot to the right
swap(pivotIndex, right);
int storeIndex = left;
for (int i = left; i < right; i++) {
int elm = m_buffer[i];
if (compare.compare(elm, pivotValue) <= 0) {
swap(storeIndex, i);
storeIndex = storeIndex + 1;
}
}
// Move pivot to its final place
swap(storeIndex, right);
// End partition
// Shorter part is regular recursion
// Longer part is tail recursion
if (storeIndex - left < right - storeIndex) {
quicksort(left, storeIndex - 1, compare, seed);
left = storeIndex + 1;
} else {
quicksort(storeIndex + 1, right, compare, seed);
right = storeIndex - 1;
}
}
}
