how to use odp contents files "contents.rdf.u8" and "structure.rdf.u8"

hi
I am parsing ODP data usign rss parser.I don't know how can i use these files.because these files are too large.and I do not know what is the prupose of "structure.rdf.u8" and "content.rdf.u8" plz some body also tell me this and also how to use these files to parse.I have checked my parser for some small fiel that is working correctly.
thanks
Usman

Structure contains the ODP category structure - all 600 000 categories of it.

Content contains all the sites listed in the ODP - all 6 000 000 of them.