From: Junio C Hamano Date: Thu, 07 Sep 2006 01:11:20 GMT Subject: Re: A look at some alternative PACK file encodings Message-ID: <7v1wqo5vlz.fsf@assigned-by-dhcp.cox.net> In-Reply-To: Nicolas Pitre writes: > On Wed, 6 Sep 2006, Jon Smirl wrote: > >> Shawn is doing some prototype work on true dictionary based >> compression. I don't know how far along he is but it has potential for >> taking 30% off the Mozilla pack. > > BTW I'm half-way done with support for deltas which base object is > referenced with an offset in the pack instead of a hash. It is quite > messy though since it touches pretty core code all over the place when > it comes to fetching objects out of a pack. I wonder how you made unpack-objects to work with it. Do you store an extra bit in the packed stream to say "this object will be used as a delta base for later objects so remember its offset and resulting SHA1", or do you just remember every entry as you unpack?