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From "Stefan Bodewig (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (COMPRESS-263) Add DEFLATE support
Date Tue, 17 Jun 2014 04:35:01 GMT

    [ https://issues.apache.org/jira/browse/COMPRESS-263?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14033426#comment-14033426
] 

Stefan Bodewig commented on COMPRESS-263:
-----------------------------------------

Well, that's only four bits of the first byte, this is bound to cause a lot of false positives
so we better don't go that route IMHO.  Thanks for your investigation.

Counting on the output side should be easy, but interestingly the other compression format
don't seem to do this either (only the archivers do).  So let's skip that for deflate.  I
also only now realized  XZCompressorInputStream's count is doing just what you have implemented
as well, I'll look into it myself.  There is org.apache.commons.compress.utils.CountingInputStream
that used to be wrapped around the original input for some formats but no longer seems to
be used.

Re: withZlibHeader - see svn revision 1603054

> Add DEFLATE support
> -------------------
>
>                 Key: COMPRESS-263
>                 URL: https://issues.apache.org/jira/browse/COMPRESS-263
>             Project: Commons Compress
>          Issue Type: New Feature
>          Components: Compressors
>            Reporter: Matthias Stevens
>              Labels: features
>             Fix For: 1.9
>
>         Attachments: COMPRESS-263_DeflateSupport.patch, COMPRESS-263_DeflateSupport_v1.1.patch,
bla.tar.deflate, bla.tar.deflatez
>
>
> GZIP is not a compression algorithm "as such". The de facto (and currently the only supported)
compression algorithm it uses is DEFLATE.
> GZIP adds a header of minimum 10 bytes and a footer of 8 bytes to a "deflated" data stream.
Find out more here: http://en.wikipedia.org/wiki/Gzip#File_format
> I have no problem with the current GZIP support, but it would be nice if CommonsCompress
would also have compression and decompression support for "raw" DEFLATE streams and DEFLATE
streams with the zlib header.
> Similarly to the GZIP support in CommonsCompress these functionality can be implemented
very easily using the standard java.util.zip package, as done in the provided patch.



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