Too Busy For Words - the PaulWay Blog

Wed 15th Jan, 2014

Ignorable compression

On the way home from LCA, and on a whim, in Perth I started adding support for LZO compression to Cfile.

This turned out to have unexpected complications: while liblzo supports the wide variety of compression methods all grouped together as "LZO", it does not actually created '.lzo' files. This is because '.lzo' files also have a special header, added checksums, and file contents lists a bit like a tar file. All of this is added within the 'lzop' program - there is no external library for reading or writing lzo files in the same way that zlib handles gz files.

Now, I see three options here:

Yeah, I'm going for option one there.

LZO is a special case: it does a reasonable job of compression - not quite as much as standard gzip - but its memory requirements for compression can be miniscule and its decompression speed is very fast. It might work well for compression inside the file system, and is commonly used in consoles and embedded computers when reading compressed data. But for most common situations, even on mobile phones, I imagine gzip is still reasonably quick and produces smaller compressed output.

Now to put all the LZO work in a separate git branch and leave it as a warning to others.

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