BarcodeGenerator::qr_encode_alphanumeric

private function qr_encode_alphanumeric($data, $version_group) {
	$alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:';
	$code = array(0, 0, 1, 0);
	$length = strlen($data);
	switch ($version_group) {
		case 2:  /* 27 - 40 */
			$code[] = $length & 0x1000;
			$code[] = $length & 0x0800;
		case 1:  /* 10 - 26 */
			$code[] = $length & 0x0400;
			$code[] = $length & 0x0200;
		case 0:  /* 1 - 9 */
			$code[] = $length & 0x0100;
			$code[] = $length & 0x0080;
			$code[] = $length & 0x0040;
			$code[] = $length & 0x0020;
			$code[] = $length & 0x0010;
			$code[] = $length & 0x0008;
			$code[] = $length & 0x0004;
			$code[] = $length & 0x0002;
			$code[] = $length & 0x0001;
	}
	for ($i = 0; $i < $length; $i += 2) {
		$group = substr($data, $i, 2);
		if (strlen($group) > 1) {
			$c1 = strpos($alphabet, substr($group, 0, 1));
			$c2 = strpos($alphabet, substr($group, 1, 1));
			$ch = $c1 * 45 + $c2;
			$code[] = $ch & 0x400;
			$code[] = $ch & 0x200;
			$code[] = $ch & 0x100;
			$code[] = $ch & 0x080;
			$code[] = $ch & 0x040;
			$code[] = $ch & 0x020;
			$code[] = $ch & 0x010;
			$code[] = $ch & 0x008;
			$code[] = $ch & 0x004;
			$code[] = $ch & 0x002;
			$code[] = $ch & 0x001;
		} else {
			$ch = strpos($alphabet, $group);
			$code[] = $ch & 0x020;
			$code[] = $ch & 0x010;
			$code[] = $ch & 0x008;
			$code[] = $ch & 0x004;
			$code[] = $ch & 0x002;
			$code[] = $ch & 0x001;
		}
	}
	return $code;
}