commons-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Dawid Weiss (JIRA)" <>
Subject [jira] [Commented] (COMPRESS-380) Support for ENHANCED_DEFLATED (Deflate64) in ZIP files
Date Mon, 08 Jan 2018 08:17:00 GMT


Dawid Weiss commented on COMPRESS-380:

I'll check again once I get back home, thanks Stefan. I did look at the changes and they look
good. I can't decide whether those extensive sanity checks should be in there at all times
(and shouldn't be just in assertion-enabled mode); I think it'll slow down decompression by
a large factor. Whether this is of practical importance, I've no idea. 

I also looked at the bit reader yesterday and wondered if it'd be a better idea to make a
bit reader factory depending on byte order, then the returned implementation could be optimized
for a particular byte order and not do so many conditionals. While this would mean virtual
method calls, in practice these would be predominantly homogeneous and would inline fairly

Maybe worth taking a look at - if you agree and file an issue, I may take a look in a spare
moment. I am fond of bit-fiddling.

> Support for ENHANCED_DEFLATED (Deflate64) in ZIP files
> ------------------------------------------------------
>                 Key: COMPRESS-380
>                 URL:
>             Project: Commons Compress
>          Issue Type: New Feature
>            Reporter: Dawid Weiss
>             Fix For: 1.16
>         Attachments:,,,,
compress-380.diff,, input2
> Some of the (large) ZIP files we try to process currently will throw this:
> {code}
> UnsupportedZipFeatureException: unsupported feature method 'ENHANCED_DEFLATED' 
> {code}
> which is a bummer since JDK's implementation also doesn't support Deflate64. This seems
to be PKWare's extensions, although code to decrypt it exists in zlib (and is appropriately
licensed, I believe).

This message was sent by Atlassian JIRA

View raw message