Branko Čibej wrote on Thu, Mar 14, 2013 at 00:43:24 +0100: > On 14.03.2013 00:07, Bo Chen wrote: > > Can anyone help me make clear this question? In SVN, if I have two > > versions A and B. I compute a delta of B against A, i.e., I can > > recover B by A and this delta. My question is, can I recover A by > > using B and the same delta? > > No. It's theoretically possible to reverse a delta, but to do that, you > must have both A and B available.
If you have A and B, you can just do (A-B) to get a reversed delta. Or maybe you mean that (A-B) can be computed more efficiently given (A,B,B-A) than given (A,B)? > This is because the representation of > the delta between A and B does not show content that was removed, only > content that was copied from a and new content added to B. > > -- Brane > > > -- > Branko Čibej > Director of Subversion | WANdisco | www.wandisco.com >
