Error Correction Libraries?

Question

I'm interested in using a Reed-Solomon error correction [http://en.wikipedia.org/wiki/Reed%E2%80%93Solomon_error_correction as a reference] to try to rebuild files from partial bits of a file. I'm doing this as a personal interest.

I recently read about WuaLa [http://www.wua.la/] and I'm interested in how they leverage Reed-Solomon to reconstruct files from partial files.

Does anyone know of libraries that are already built that support Reed-Solomon? Could anyone point me to the math involved in doing this type of thing (keep in mind I'm a software guy not a math guy so if you can point to something more accessible that would be great). I've checked out part of the video [http://www.youtube.com/watch?v=3xKZ4KGkQY8] on this tool but I'm still trying to wrap my head around the math involved.

Answer 1

http://parchive.sourceforge.net/ is an open-source implementation. So you can at least read the code. I believe they also have docs on the math http://parchive.sourceforge.net/docs/specifications/parity-volume-spec/article-spec.html, and so does Wikipedia http://en.wikipedia.org/wiki/Reed-Solomon_error_correction.

Answer 2

There is ZFEC package for python http://pypi.python.org/pypi/zfec that implements Reed Solomon algorithm for creating and restoring files from parts and does exactly what you want. You can use it without coding - as a command line utility. Its core is a single .c file. I've actually used it for as erasure code for transferring real time video.