We're currently creating a device for a customer that will get a block of data (like, say, 5-10KB) from a PC application. This is a bit simplified, so assume that the data must be passed and uncompressed a lot, not just once a year. The communication channel is really, really slow, so we'd like to compress the data beforehand, pass to the device and let it uncompress the data to its internal flash. The device itself, however, runs on a micro controller that is not really fast and does not have a lot of memory. It has enough flash memory to store the result, and can uncompress the data block as it is received, but it may not have enough RAM to store the entire compressed or uncompressed (or even both!) data blocks. And of course, it doesn't have an operating system or other luxury.
This means we need a sufficiently fast uncompression algorithm that does not use a lot of memory. The compression can be slow and ugly, since we're doing it on the PC side. C or .NET code preferred though for compression, to make things easier. The uncompression code should be in C, since it's unlikely that someone has an ASM optimized version for our controller.
We found LZO, which would be almost perfect for us, but it has a so-called "free" license (GPL) by default, which makes it totally unusable for our customer. The author says that commercial licenses are available on request, but unfortunately he's currently unreachable (for non-technical reasons, like the news on his site say).
I found a few other libraries, including the puff.c from zlib, and we're still investigating, but I thought I'd ask for your experience:
Which compression algorithm and/or library do you recommend for embedded purposes, given that the decompression device has really limited resources and source code and a commercial license are required?
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