[thristian]

That's interesting. So far as I know, the only documentation of the RAR compression algorithm is the official UnRAR tool¹, which (among other things) restricts you from using it to create a RAR-writer. There's also the GPL'd "unrar" based on UnRAR 2 (which doesn't handle modern RAR 3.x archives), and the GPL'd "unar"². Given that this is under the MIT licence, it can't be derived from any of those other tool, so I guess it must be a from-scratch reimplementation.

Well done!

¹: http://www.rarlab.com/rar/unrarsrc-5.0.12.tar.gz ²: http://unarchiver.c3.cx/commandline

[anonymous]

A more likely explanation is that the author frankly doesn't give a damn about such restriction.

[_delirium]

This doesn't look like it actually does decompression, which makes the amount of reverse-engineering it needs to do considerably less.

[justincormack]

The GPL is a copyright license and does not apply to a reimplementation.