RFR: 8374644: Regression in GZIPInputStream performance after JDK-7036144 [v2]

[Jaikiran Pai]

On Wed, 7 Jan 2026 13:47:24 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> Jaikiran Pai has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   use -1 to represent absence of a GZIP header, from readHeader() method
>
> src/java.base/share/classes/java/util/zip/GZIPInputStream.java line 195:
> 
>> 193:      * If failOnEOF is false and if the given InputStream has already
>> 194:      * reached EOF when this method was invoked, then this method returns
>> 195:      * 0 (indicating that there's no GZIP member header).
> 
> Have you tried using -1 for EOF instead of 0? I think would make it easier to understand at the use sites.

I had very briefly considered it, but there was a call site (within this class) which was doing:

m += readHeader(in);

so I decided to use `0` to prevent accidental additions of negative value. 

Having said that, that is no longer a concern with the current changes in this PR and there are only 2 call sites to this (private) method in this class. So your suggestion of using `-1` as a return value sounds good to me. I've updated the PR accordingly.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29092#discussion_r2668587977