private final function sortIntervals( $a, $b )
    {
        if( 0 !== $lowerCompare = $this->sort( $a[0], $b[0], self::NULL_IS_LOW ) ) {
            return $lowerCompare;
        }
        return -$this->sort( $a[1], $b[1], self::NULL_IS_HIGH );
    }
private final function sortIntervals( $a, $b )
    {
        if( 0 !== $lowerCompare = $this->sort( $a[0], $b[0], self::NULL_IS_LOW ) ) {
            return $lowerCompare;
        }
        return -$this->sort( $a[1], $b[1], self::NULL_IS_HIGH );
    }
private final function sortIntervals ( $ a , $ b ) { if ( 0 !== $ lowerCompare = $ this -> sort ( $ a [ 0 ] , $ b [ 0 ] , self :: NULL_IS_LOW ) ) { return $ lowerCompare ; } return - $ this -> sort ( $ a [ 1 ] , $ b [ 1 ] , self :: NULL_IS_HIGH ) ; }
Sort two intervals
@param array $a
@param array $b
@return -1,0,1
Sort two intervals