reverse xdelta patch

Is there way to make reversing x开发者_Go百科delta patch?

For example:

A - version 1 of file.

B - version 2 of file.

P - patch.

File B we can renew by appliing patch P to file A.

Is there way to renew file A if I have file B and patch P ?

---

It's a requested feature, but currently you have to generate two patches:

xdelta3 -e -s A B P1
xdelta3 -e -s B A P2