Re: Java text compression

From:
Robert Klemme <shortcutter@googlemail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 21 Nov 2007 21:57:11 +0100
Message-ID:
<5qjkd8F10anglU1@mid.individual.net>
On 18.11.2007 23:28, Chris wrote:

Eric Sosman wrote:

Chris wrote:

What's the fastest way to compress/decompress text?


    If you're really interested in "the fastest way" to the
exclusion of all other concerns, then don't compress at all.
Bingo! Problem solved!


Um, actually no. When you're dealing with really large datasets it's
generally faster to compress than not to compress. The reason is that
compressed data requires less disk I/O.

Not always, of course; really processor-intensive compression schemes
can make you processor-bound. But in general, that's the case.

Yup, we've benchmarked it.

    You might be happier with a compression scheme that did
a little better at reducing the size of the data, but now you
can't get a sensible answer until you describe the trade-offs
you're willing to make. For example, if you were offered a
compression scheme that ran ten percent faster than your current
method but emitted fifteen percent more data, would you take it
or reject it?


Yes, but I don't think that knowing that is essential to answering the
question. The question is really about finding better tradeoffs than we
can get with char conversion + zip conversion.


If you have strings already then serialization is one form to convert
them into binary data (which can be compressed with Java's standard
lib). If you can get rid of UTF-8 compression this might be an alternative.

    robert

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