jka-compr: Conditional mode?

[Marcus Harnisch]

Hi all

I have to deal with files generated by a tool, which stores them as 
either compressed or uncompressed, depending on some configuration. The 
file extension is the same in both cases.

Data stored in ‘jka-compr-compression-info-list’ already supports an 
entry ‘file-magic-chars’. Could that be used to determine whether to 
treat a file as (un)compressed?

Thanks,
Marcus