/**
* Returns an invalid cell id guaranteed to be larger than any valid cell id.
* Useful for creating indexes.
*#/
* public static S2CellId sentinel() {
* return new S2CellId(MAX_UNSIGNED); // -1
* }
*
* /**
* Return a cell given its face (range 0..5), 61-bit Hilbert curve position
* within that face, and level (range 0..MAX_LEVEL). The given position will
* be modified to correspond to the Hilbert curve position at the center of
* the returned cell. This is a static function rather than a constructor in
* order to give names to the arguments.
*/
public static function fromFacePosLevel($face, $pos, $level)
{
$s2cell = new S2CellId(($face << self::POS_BITS) + ($pos | 1));
return $s2cell->parent($level);
}
