On 14.03.2013 01:03, Daniel Shahaf wrote:

*> 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)?
*

I believe it can be more efficient in terms of the cost for producing

the inverse delta in some cases, but I never researched that in detail

because its clear that the /size/ of such a delta would not be optimal.

-- Brane

--
Branko Čibej
Director of Subversion | WANdisco | www.wandisco.com

Received on 2013-03-14 01:21:18 CET