RFR: 8316190: Improve MemorySegment::toString

[Claes Redestad]

On Thu, 14 Sep 2023 13:44:59 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> src/java.base/share/classes/jdk/internal/foreign/Utils.java line 277:
>> 
>>> 275:     }
>>> 276: 
>>> 277:     public static String toHexString(long value) {
>> 
>> We intend to use this utility method in coming PRs.
>
> The String concat code is really good at optimizing, but this will require a new string be created.
> $0.02,Roger

Why not `HexFormat.of().withPrefix("0x").formatHexString(long)` I thought, then realized there's no such method, only `toHexDigits` which ignores the `HexFormat.prefix`. Having a format method that adds the prefix (and any suffix + delimiters) means creating this string could be done in a single step without concatenation, and we'd consolidate all manners of usage to a single place. Seems there might be room for improvement here.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/15740#discussion_r1326032912