rrdiff - Ruby bindings to librsync/rdiff.
Lets say you have two files oldfile and newfile where newfile is a modified version of oldfile. We want to be able to apply the change to oldfile such that it becomes newfile.
The first process is to create a signature for the oldfile. The parameters are the original file and where you want to store the signature file.
RRDiff.signature("oldfile", "sigfile")
Then from the newfile and the sigfile generate a delta. Deltafile is where the delta is stored.
RRDiff.delta("newfile", "sigfile", "deltafile")
Finally, apply the deltafile to the oldfile to create the patchedfile which should be equivalent to newfile.
RRDiff.patch("oldfile", "deltafile", "patchedfile")
There is also a File interface, that you can pass File instances. It will return Tempfiles.
RRDiff::File.signature(oldfile) #=> <File>
RRDiff::File.delta(sigfile, newfile) #=> <File>
RRDiff::File.diff(oldfile, newfile) #=> <File>
RRDiff::File.patch(oldfile, deltafile) #=> <File>