if (aliasToComparatorMapping.inverse().containsKey(comparator)) {
byte a = aliasToComparatorMapping.inverse().get(comparator);
if (desc) {
a = (byte) Character.toUpperCase((char) a);
}
out.writeShort((short) (0x8000 | a));
}
else {
out.writeShort((short) comparator.length());
out.write(ByteBufferUtil.bytes(comparator));
}