rollhash

Rolling hash based file diffing tool

An rdiff like tool that can produce 'deltas' between the original and the new file. To compare the two files not necessary to have the original file. rollhash can create a 'signature' file from the original file. This can be used to create the 'deltas'.

Usage

rollhash has the same API as rdiff

Usage:
  rollhash signature [BASIS [SIGNATURE]]
  rollhash delta SIGNATURE [NEWFILE [DELTA]]

Signature

signature generates a signature from the base file. Signature describes the hash of the chunks in map[string][]int format, where the key is the hash and value is the list of the chunks. This map also contains the chunk size used during the generation. The chunk size depends on the input data length, between the min and max limit value.

parameters:
  * BASIS - input file path, mandatory parameter
  * SIGNATURE - output file path, optional parameter, if not provided then it prints out to the standard out.

Delta

delta generates the diff between the original file and the new file. The 'deltas' shows which chunk has been changed in a map[int][]byte format. Where the key is the chunk index and the value the new data. This delta can be used to apply on the original file to get the new file.

parameters:
  * SIGNATURE - signature file path, mandatory parameter
  * NEWFILE - input file path, mandatory parameter
  * DELTA - output file path, optional parameter, if not provided then it prints out to the standard out.

How to build

You can build rollhash with the standard go build command.

go build -o rollhash cmd/rollhash/*.go