RFR: 8242842: Avoid reallocating name when checking for trailing slash in ZipFile.getEntryPos

[Lance Andersen]

Hi Claes,

I think this looks good overall.

Vwar
LNXW

> On Apr 15, 2020, at 8:58 AM, Claes Redestad <claes.redestad at oracle.com> wrote:
> 
> Hi,
> 
> a trivial optimization to ZipFile.getEntryPos extracted from some
> experiments conducted mostly by Eirik Bjørsnøs.
> 
> Webrev: http://cr.openjdk.java.net/~redestad/8242842/open.00/
> Bug:    https://bugs.openjdk.java.net/browse/JDK-8242842
> 
> This removes an extra array copy on every miss, and the patch means a
> small speed-up on a few startup applications I've tested (Spring
> Petclinic: ~50ms faster).
> 
> This is an optimization which was lost in translation when porting from
> native to Java[1] in JDK 9. The native implementation allocates an
> array that can fit the extra '/' if needed, and updates the array in
> place for the follow-up check.
> 
> Thanks!
> 
> /Claes
> 
> [1] https://bugs.openjdk.java.net/browse/JDK-8145260

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 <http://oracle.com/us/design/oracle-email-sig-198324.gif>Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
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