[foreign-memaccess] [Rev 02] RFR: Add MemorySegment::mismatch

[Paul Sandoz]

On Wed, 20 May 2020 18:18:49 GMT, Chris Hegarty <chegar at openjdk.org> wrote:

>> Hi,
>> 
>> As part of feedback on the Foreign Memory API (when experimenting with its usage internally in the JDK), a small number
>> of potential usability enhancements could be made to the API. This is the fourth such, and last on my current todo
>> list.  This change proposes to add a new method:
>> MemorySegment::mismatch
>> 
>> The mismatch semantic is very useful for building equality and comparison logic on top of segments. I found that I
>> needed such when modeling and comparing native socket address in the JDK implementation. It is possible to write your
>> own, but requires a non-trivial amount of not-trivial code - to do it right! I also think that we can provide a more
>> efficient implementation building on top of the JDK's internal mismatch support.  I still need to do some perf testing
>> and add a micro-benchmake ( Maurizio suggested possibly amending TestBulkOps ). There is also the question about
>> possibly improving the JDK's internal implementation to work on long sizes (which could be done separately). For now, I
>> just want to share the idea, along with the proposed specification and initial implementation.  Comments welcome.
>
> Chris Hegarty has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev
> excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since
> the last revision:
>  - Integrate Paul's review comment
>  - Merge remote-tracking branch 'origin/foreign-memaccess' into mismatch
>  - Move implementation into vectorizedMismatchLarge, and address other review comments.
>  - Initial mismatch implementation

Marked as reviewed by psandoz (Committer).

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PR: https://git.openjdk.java.net/panama-foreign/pull/180