You should tried looking at error correction text book to gain a better understanding. For a reed solomon, you could easily implement a small code using a meggitt decoder technique. For the longing code, you would have to use some search algorithm i.e. chien or some other(search the internet). The encoder is just LFSR with some XOR logic.
I guess you haven't tried hard enough. I just type golay decoder and encoder in google and I found an implementation using wavelet transform. I am quite suprise you can't find Reed Solomon in the internet. You should look at 4i2i website , it gives a
good introduction on RS.
I buy book of "ECC programming". It contain a good description of Golay & Reed-solomon encoder-decoder.
C-code source you can find from official sute this book: http://www.the-art-of-ecc.com/topics.html