public function toRegex(Range $range)
{
$min = $range->getMin();
$max = $range->getMax();
if ($min === $max) {
return $min;
}
if ($min > $max) {
return sprintf('%d|%d', $min, $max);
}
$positives = [];
$negatives = [];
if ($min < 0) {
$newMin = 1;
if ($max < 0) {
$newMin = abs($max);
}
$newMax = abs($min);
$negatives = $this->splitToPatterns($newMin, $newMax);
$min = 0;
}
if ($max >= 0) {
$positives = $this->splitToPatterns($min, $max);
}
return $this->siftPatterns($negatives, $positives);
}
private function getKey(Range $range)
{
return sprintf('%d:%d', $range->getMin(), $range->getMax());
}
/**
* Searches a range
*
* @param Range $range
*
* @return RangeIterator
*/
public function searchRange(Range $range)
{
$iterator = $this->getIterator();
// find start
$start = null;
$binarySearch = new BinarySearch($this);
$startHint = $binarySearch->search($range->getMin());
if ($startHint == null) {
return new RangeIterator($iterator, Range::getEmptyRange());
}
$iterator->setOffset($startHint->getOffset(), Parser::HINT_RESULT_BOUNDARY);
if (!$range->contains($startHint->getKey()) && $startHint->getKey() <= $range->getMin()) {
// shift $startHint higher
foreach ($iterator as $result) {
if ($range->contains($result->getKey())) {
$start = $result;
break;
}
}
} else {
// shift $startHint lower
if ($range->contains($startHint->getKey())) {
$start = $startHint;
}
$iterator->setDirection(KeyReader::DIRECTION_BACKWARD);
foreach ($iterator as $result) {
// Skip everything which is too big
if (!$range->contains($result->getKey() && $result->getKey() >= $range->getMax())) {
continue;
}
// shift the start left until no more key is included
if ($range->contains($result->getKey())) {
$start = $result;
} else {
break;
}
}
}
if (is_null($start)) {
return new RangeIterator($iterator, Range::getEmptyRange());
}
$iterator = $this->getIterator();
$iterator->setOffset($start->getOffset(), Parser::HINT_RESULT_BOUNDARY);
return new RangeIterator($iterator, $range);
}