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https://issues.apache.org/jira/browse/COMPRESS-391?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16004285#comment-16004285
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Stefan Bodewig commented on COMPRESS-391:
-----------------------------------------
I've pushed additional commits on the COMPRESS-391 branch. Feel free to ignore
what I've done. Really.
Reading is implemented as well ({{parseFromLocalFileData}} reads the padding
length).
I've installed zipalign and it always aligns at 4 byte boundaries (and does so
for all stored entries). I wonder whether alignment should be a property of
{{ZipArchiveOutputStream}} in addition to {{ZipArchiveEntry}} in order to apply
it to all stored entries as well. You are correct, zipalign simply adds zeros
which ends up in an {{UnparseableExtraField}} when we read it.
As for proposing the extra field, it won't hurt, I'm just not sure how quick
the response will be (and {{l}} is not a valid hex character ;-) 0xa11e?). Hmm,
take a look at "4.6.10 -Microsoft Open Packaging Growth Hint (0xa220)" this
looks as if we could use it, I couldn't find any information what its real
purpose would be. Of course it doesn't store the alignment value you propose.
> Zip entries alignment
> ---------------------
>
> Key: COMPRESS-391
> URL: https://issues.apache.org/jira/browse/COMPRESS-391
> Project: Commons Compress
> Issue Type: New Feature
> Components: Archivers
> Affects Versions: 1.13
> Reporter: Zbynek Vyskovsky
> Labels: features, github-import, patch
> Fix For: 1.14
>
>
> Similarly to COMPRESS-390, there are requirements of the zip content to be
> mapped directly into memory and therefore may require special alignment on
> the embedded files. E.g. libraries may be aligned to page (4096-bytes)
> boundary, images on 4-bytes boundary etc. By alignment it's meant the offset
> from the beginning of file where the actual data stream starts, not the
> header.
> One of the cases was (still is?) Android APK for which zipalign utility was
> created.
> It would be useful if commons-compress ZipArchiveOutputStream supports
> something similar directly in its API.
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