Simple Binary Patch is a pair of functions that can create a diff between two binary files of the same length and and later patch the original file to become the new one.
I was working on patching firmware on an embedded device. My code would load the original firmware from memory and then attempt to patch it with modified code I had written elsewhere. The binary images were sparsely different, and I needed an easy way to patch the original firmware since copying the whole modified firmware file was impractical. Since this was on an embedded device, I couldn't use the features of other binary diffs since they used compression, malloc, and other complications. I made this to be as simple as possible so it would work on pretty much everything.
Simple Binary Patch requires fixed width data types. It includes stdint.h, but if that's not available on your platform you'll need to typedef your own.
Please see bin_patch.h for the documentation. It is not here to reduce redundancy.
This algorithm works best on sparsely different files, or with files that have long chunks of similarity. There is overhead of 2x the size of what len_t is configured as.
I also included command line tools that allow you to generate and apply diffs to binary files. I also wrote a short example file that I use to test the algorithm, although it's not very thorough.
Build with:
make # makes generate_patch and apply_patch
make example # makes the example code
make clean # deletes the binaries
- Better compression
- Automated tests.
- Checksum checking, so we don't clobber a target with data we know to be corrupted.
SimpleBinaryPatch is the brainchild of Tucker Osman, but Wesley Van Pelt raised that child into a respectable program that's far more structured and efficient. The repo is maintained by Tucker.