Re: compressor
Le vendredi 24 août 2012 à 10:10 +0100, Jon Dowland a écrit :
>
> Most compressors work on a block-cipher model in order to support stream
> operation and so the compressor doesn't have a global view of the data being
> compressed.
At least with 7zip and xz, you can tweak the block size directly and at
least LZMA, Deflate, PPMd are able to do multiple pass.
> That's why subsequent manual passes can (sometimes) have a good
> effect, especially with e.g. enormous log files with a lot of repetition: local
> areas of the file being compressed are treated in isolation, but the resulting
> compressed blocks have a lot of (compressed!) repetition. In practise it's
> almost certainly very rarely worth bothering.
That makes sense. AFAIK, you can't manually set the block size with gzip
which is a shame for non-streamed files.
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