Re: [Trisquel-users] Need help modifying this program to make it free

[legimet . calc]

The nonfree code is in src/egtb, and it's just an implementation of LZW, a  
standard algorithm used in GIF files. It actually used to be covered by  
software patents, but those expired a decade ago. There are 2 choices: either  
get some LZW implementation from somewhere else (you might have to make the  
API compatible) or write your own.

I actually replaced a nonfree implementation of RIPEMD in a debian package  
with my own a few weeks ago, and learned about hashing algorithms in the  
process. So writing your own can be quite fun, although there's no reason to  
do that if there's an existing API compatible implementation of LZW.