Open decoded range options against an unknown size, producing a
negative offset for suffix ranges (eg the last N bytes) and sending
syntactically invalid Range headers which the server ignored. A
suffix range then returned the whole file instead of the requested
tail.
Decode the options against the known object size so the offset is
always absolute, only send a Range header when one was requested, and
honour the requested count when the server ignores the Range header.
Nick Craig-Wood
846f571eb7