The asn1c compiles ASN.1 (Abstract Syntax Notation One) specifications into
the C source code. This compiler supports automatic constraints checking code
generation, parametrization, basic support for Information Object Classes.
The produced C code contains the codecs for BER/DER/CER/PER/XER encoding rules.

See asn1c-usage.pdf and asn1c(1) manual page for details.