[Users] parsing P-Asserted-Identity

Hi! I wonder how I can parse the body of the P-Asserted-Identity: header. This header allows several syntax, e.g: P-Asserted-Identity: "Klaus Darilion" <tel:+43123> P-Asserted-Identity: tel:+43123;context P-Asserted-Identity: tel:201-555-0123;phone-context=+1 P-Asserted-Identity: "nice guy" <sip:ng;abc=def@nicedomain;foo=bar> In my case I want to: 1. check if it is a tel URI or not 2. Get the phone number from the addr-spec 3. Get the parameters (phone-context, ...) Are there generic functions available to parse name-addr, addr-spec, SIP-URIs and tel URIs? Or do I have to use avp_check and avp_subst with some complicated regexps? Thanks Klaus