Looking for a CSN.1 library

Hi all, Does anyone know a good C/C++ library for CSN.1 bitstream reading/writing? We're working on a GPRS implementation for OpenBTS and we don't want to code all those RLC/MAC messages by hands when we can do this automatically. Right now we think that the easiest way is to re-purpose csn1 "library" from Wireshark - adopt it to OpenBTS bitstream operations and add support for writing to bitstream. Then we can even re-use those RLC/MAC messages already converted to macros' for Wireshark's rlcmac dissector. But we would appreciate if someone points us to a better way of doing this. -- Regards, Alexander Chemeris.