protected function getWebpSize($data, $format)
	{
		switch ($format)
		{
			case self::WEBP_FORMAT_SIMPLE:
				$this->size = unpack('vwidth/vheight', substr($data, 10, 4));
			break;

			case self::WEBP_FORMAT_LOSSLESS:
				// Lossless uses 14-bit values so we'll have to use bitwise shifting
				$this->size = array(
					'width'		=> ord($data[5]) + ((ord($data[6]) & 0x3F) << 8) + 1,
					'height'	=> (ord($data[6]) >> 6) + (ord($data[7]) << 2) + ((ord($data[8]) & 0xF) << 10) + 1,
				);
			break;

			case self::WEBP_FORMAT_EXTENDED:
				// Extended uses 24-bit values cause 14-bit for lossless wasn't weird enough
				$this->size = array(
					'width'		=> ord($data[8]) + (ord($data[9]) << 8) + (ord($data[10]) << 16) + 1,
					'height'	=> ord($data[11]) + (ord($data[12]) << 8) + (ord($data[13]) << 16) + 1,
				);
			break;
		}
	}