On Thu, 24 Jul 2025 13:18:03 GMT, Raffaello Giulietti <rgiulie...@openjdk.org> wrote:
>> Shaojin Wen has updated the pull request incrementally with one additional >> commit since the last revision: >> >> Update src/java.base/share/classes/java/lang/StringUTF16.java >> >> Co-authored-by: Chen Liang <li...@openjdk.org> > > src/java.base/share/classes/java/lang/StringUTF16.java line 1490: > >> 1488: val, >> 1489: Unsafe.ARRAY_BYTE_BASE_OFFSET + ((long) index << 1), >> 1490: (long) (end - off) << 1); > > The documentation of `copyMemory()` is not super-clear about endianness. > But it seems to imply that in this case it behaves as if it were to copy > `short`s, so endianness seems to be preserved. > > The invocation of `copyMemory()` here implicitly assumes that > `ARRAY_CHAR_INDEX_SCALE` and `ARRAY_BYTE_INDEX_SCALE` are 2 and 1, resp., > which seems quite reasonable but not written in the stone. I recall runtime requires UTF16 byte array and char array have exactly the same layout - would be nice if we keep this in the design notes for the string implementation classes, such as on the class header. (Useful notes could include that indices are char-based, UTF16 byte[] and char[] has identical layout, etc.) ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/24773#discussion_r2228671899
