RFR: 8253821: Improve ByteBuffer performance with GCM [v4]

[Anthony Scarpino]

On Mon, 16 Nov 2020 19:23:20 GMT, Valerie Peng <valeriep at openjdk.org> wrote:

>> You don't know what 'len', which includes ibuffer data, until this point in the code.
>
> Well, didn't you already calcuate the 'len' value in the beginning of the copied-from-GCTR RuntimeException check?

I'm removing the runtime check in the next update, it was duplicate of the ShortBufferException.  Calculating 'len' through the if() above line 818 while it is prepares the bytebuffers is good enough.

>> I thought so too, but that isn't what GCTR returns.  All the GCTR checks are RuntimeExceptions.  This check was original inside of GCTR, but I had to bring it out because of the ibuffer lengths.  I don't mind changing, it's just a strange inconsistency.
>
> GaloisCounterMode is the caller class of GCTR and this API is meant to throw ShortBufferException I think (based on the check at lines below at 820-822)...

Yes.. this check is not necessary given the ShortBufferException was already checked.  I am removing this as part of the next update

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PR: https://git.openjdk.java.net/jdk/pull/411