[op25-dev] hamming decoder

Hey, I am interested in writing the shortened hamming decoder and rs decoder for the LC information. Is there any sort of reference manuals that describe how the shortened hamming code is implemented? From looking at the op25 lib; op25_hamming.h in particular, it looks like its being done bitwise in hamming_15_decode function. i just really don't know what that giant encoding array & the small decoding array are and how those relate to the generator matrices in the tia pdf? i think i kind of have to know what those are about before i can proceed to write a decoder of the LCWs. But thereafter i suspect it shouldn't be to hard. the matrix algebra approach is how i understand how to decode hamming codes and that approach is not used in op25. furthermore I am not sure if implementing an algebraic approach would be appropriate (ie. fast enough) for our use here? so it would be a big help if I knew how exactly the hamming_15_decode function works, and in particular what those to arrays (encoding & decoding) are, and where they come from, and how the generator and parity matrices (or functions) are utilized? Thanks! -- ------ Matt D ------------