Looking for MCP2515 files

Hi,
planning to use the Sparkfun CAN-shield for some tryout projects. Have found some interesting code for logging/sniffing from a J1939 network, but lack the c and h files named "MCP2515".

Can find some threads here and there on the net but no available files for download. Anyone understanding what I'm looking for that can advise?

Thanks',
_/) P-L