Content-Encoding, Content-Range

Hi!

If I'd like to combine Content-Encoding gzip with Content-Range. Which 
offsets do I have to use in the request and response messages. Is the 
offset then pointing to a position in the original content or to a 
position in the encoded content? And what about the instance-length? Is 
it the length of the compressed or original resource?

Thank you!

Martin Thelian