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https://issues.apache.org/jira/browse/COMPRESS-428?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16245327#comment-16245327
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Stefan Bodewig commented on COMPRESS-428:
-----------------------------------------
In most cases you don't know the compressed size upfront. In order to implement
this functionality you'd have to compress the entry's data and keep in memory
(or a temporary file) together with the original data (also in memory or a
temporary file). The "in memory" part means you'd keep more than twice the size
of the original data there, something the docs should better state clearly.
> Adding option to auto-select final method(DEFLATED or STORED) for
> ZipArchiveOutputStream
> ----------------------------------------------------------------------------------------
>
> Key: COMPRESS-428
> URL: https://issues.apache.org/jira/browse/COMPRESS-428
> Project: Commons Compress
> Issue Type: Improvement
> Components: Compressors
> Affects Versions: 1.13
> Environment: commons-compress 1.13
> Reporter: Fuwei Chin
> Priority: Minor
> Labels: compress, deflated, stored
> Fix For: 1.16
>
>
> Before writing "deflated" data to output stream, check if the compressed size
> of a zip archive entry is bigger than or equal to its original size, if so
> then use method "stored" instead, just like what 7-Zip does when creating a
> zip file.
> The optimization above can be done by
> 1. adding a new option "DEFLATED_IF_NECESSARY" for
> ZipArchiveOutputStream#method.
> 2. auto-selecting final method(DEFLATED or STORED) if DEFLATED_IF_NECESSARY
> specified.
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