Implementation of rolling hash signature and delta calculation by spec.
Adler-32 is used as rolling hash algorithm, SHA1 is used as a strong hash to validate chunks equality. The original file is being split into 4Kb chunks, for each of them both hashes are calculated. The last chunk may be of a smaller size.
When the delta is generated a Adler-32 hash is being calculated in a rolling window. In case of a match to a signature SHA1 is used for verification. The current algorithm just checks if last incomplete chunk directly matches it's position in the original file which may not cover some situations. However on large files this shouldn't be critical.
Prerequisites:
- C++ compiler with C++17 support
- CMake v3.8+
Building project:
mkdir build
cd build
make
Running tests:
make run_tests
Following the instructions above should result in having rh_diff and rh_tests executables in the build/bin folder.
rh_tests executes project unit tests.
rh_diff is a command-line utility for signature amd delta generation from files. Use rh_diff --help to see usage details.