RFR: 8369564: Provide a MemorySegment API to read strings with known lengths [v7]

[Maurizio Cimadamore]

On Thu, 20 Nov 2025 08:31:12 GMT, Liam Miller-Cushon <cushon at openjdk.org> wrote:

>> src/java.base/share/classes/java/lang/foreign/MemorySegment.java line 2649:
>> 
>>> 2647:      *
>>> 2648:      * @param src      the Java string to be written into this segment
>>> 2649:      * @param dstEncoding the charset used to {@linkplain Charset#newEncoder() encode}
>> 
>> I'm not sure we have a dependency on the charset being standard?
>
> We do not, thanks, fixed.
> 
> Although I think the existing `allocateFrom(String, Charset)` method does have an undocumented dependency, because it uses `CharsetKind` to get the terminator char length, which only supports standard Charsets. If we add a fast path for UTF-16 that may need a dependency on a standard Charset (or a standard way to get the code unit size of a charset, if it has one).

Note sure I follow -- the method you mention says this:

    * @throws IllegalArgumentException if {@code charset} is not a
     *         {@linkplain StandardCharsets standard charset}


What do you mean by "undocumented dependency"?

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PR Review Comment: https://git.openjdk.org/jdk/pull/28043#discussion_r2549932198