On Tue, 19 Sep 2023 10:26:50 GMT, 温绍锦 <d...@openjdk.org> wrote:
>> If we changed DIGITS to be encoded with the uppercase digits then the >> expression could be simplified to >> ```return ucase ? v : (short) (v | 0b0010_0000_0010_0000); // or 0x2020``` > > Some performance-focused scenarios, such as UUID.toString, use lowercase, so > I think DIGITS should be lowercase. > I think this logic is somewhat complicated that explaining directly is > better: `0b0100_0000_0100_0000` is a selector that selects letters (1 << 6), > uppercase or not, and shifting it right by 1 bit incidentally becomes a bit > offset between cases (1 << 5). > > I think you can keep the original `& ~` which is clearer (as `-` will not > work had the differences not be aligned bit-wise). But you should explain > what `>> 1` does which is a major hurdle to understanding this function. I have added your explanation and it is very well written. I changed it to "-" because there is one less operation and it is easier to explain. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/15768#discussion_r1329923039
