Binary delta encoding in Python 3.6+ and C.
Based on http://www.daemonology.net/bsdiff/ and HDiffPatch, with the following features:
bsdiff, hdiffpatch and match-blocks algorithms.
sequential, hdiffpatch or in-place (resumable) patch types.
BZ2, LZ4, LZMA, Zstandard, heatshrink or CRLE compression.
Sequential patches allow streaming.
Maximum file size is 2 GB for the bsdiff algorithm. There is practically no limit for the hdiffpatch and match-blocks algorithms.
Incremental apply patch implemented in C, suitable for memory constrained embedded devices. Only the sequential patch type is supported.
SA-IS or divsufsort instead of qsufsort for bsdiff.
Optional experimental data format aware algorithm for potentially smaller patches. I don't recommend anyone to use this functionality as the gain is small in relation to memory usage and code complexity!
There is a risk this functionality uses patent https://patents.google.com/patent/EP1988455B1/en. Anyway, this patent expires in August 2019 as I understand it.
Supported data formats:
- ARM Cortex-M4
- AArch64
Project homepage: https://github.com/eerimoq/detools
Documentation: http://detools.readthedocs.org/en/latest
pip install detoolsPatch sizes, memory usage (RSS) and elapsed times when creating a patch from Python-3.7.3.tar (79M) to Python-3.8.1.tar (84M) for various algorithm, patch type and compression combinations.
See tests/benchmark.sh for details on how the data was collected.
| Algorithm | Patch type | Compr. | Patch size | RSS | Time |
|---|---|---|---|---|---|
| bsdiff | sequential | lzma | 3,5M | 662M | 0:24.29 |
| bsdiff | sequential | none | 86M | 646M | 0:15.20 |
| hdiffpatch | hdiffpatch | lzma | 2,4M | 523M | 0:13.74 |
| hdiffpatch | hdiffpatch | none | 7,2M | 523M | 0:10.24 |
| match-blocks | sequential | lzma | 2,9M | 273M | 0:08.57 |
| match-blocks | sequential | none | 84M | 273M | 0:01.72 |
| match-blocks | hdiffpatch | lzma | 2,6M | 212M | 0:06.07 |
| match-blocks | hdiffpatch | none | 9,7M | 212M | 0:01.30 |
Same as above, but for MicroPython ESP8266 binary releases (from 604k to 615k).
| Algorithm | Patch type | Compr. | Patch size | RSS | Time |
|---|---|---|---|---|---|
| bsdiff | sequential | lzma | 71K | 46M | 0:00.64 |
| bsdiff | sequential | none | 609K | 27M | 0:00.33 |
| hdiffpatch | hdiffpatch | lzma | 65K | 42M | 0:00.37 |
| hdiffpatch | hdiffpatch | none | 123K | 25M | 0:00.32 |
| match-blocks | sequential | lzma | 194K | 46M | 0:00.44 |
| match-blocks | sequential | none | 606K | 25M | 0:00.22 |
| match-blocks | hdiffpatch | lzma | 189K | 43M | 0:00.38 |
| match-blocks | hdiffpatch | none | 313K | 24M | 0:00.19 |
Examples in C are found in c.
Create a patch foo.patch from tests/files/foo/old to
tests/files/foo/new.
$ detools create_patch tests/files/foo/old tests/files/foo/new foo.patch
Successfully created 'foo.patch' in 0.01 seconds!
$ ls -l foo.patch
-rw-rw-r-- 1 erik erik 127 feb 2 10:35 foo.patch
Create the same patch as above, but without compression.
$ detools create_patch --compression none \
tests/files/foo/old tests/files/foo/new foo-no-compression.patch
Successfully created 'foo-no-compression.patch' in 0 seconds!
$ ls -l foo-no-compression.patch
-rw-rw-r-- 1 erik erik 2792 feb 2 10:35 foo-no-compression.patch
Create a hdiffpatch patch foo-hdiffpatch.patch.
$ detools create_patch --algorithm hdiffpatch --patch-type hdiffpatch \
tests/files/foo/old tests/files/foo/new foo-hdiffpatch.patch
Successfully created patch 'foo-hdiffpatch.patch' in 0.01 seconds!
$ ls -l foo-hdiffpatch.patch
-rw-rw-r-- 1 erik erik 146 feb 2 10:37 foo-hdiffpatch.patch
Lower memory usage with --algorithm match-blocks algorithm. Mainly
useful for big files. Creates slightly bigger patches than bsdiff
and hdiffpatch.
$ detools create_patch --algorithm match-blocks \
tests/files/foo/old tests/files/foo/new foo-hdiffpatch-64.patch
Successfully created patch 'foo-hdiffpatch-64.patch' in 0.01 seconds!
$ ls -l foo-hdiffpatch-64.patch
-rw-rw-r-- 1 erik erik 404 feb 8 11:03 foo-hdiffpatch-64.patch
Non-sequential but smaller patch with --patch-type hdiffpatch.
$ detools create_patch \
--algorithm match-blocks --patch-type hdiffpatch \
tests/files/foo/old tests/files/foo/new foo-hdiffpatch-sequential.patch
Successfully created 'foo-hdiffpatch-sequential.patch' in 0.01 seconds!
$ ls -l foo-hdiffpatch-sequential.patch
-rw-rw-r-- 1 erik erik 389 feb 8 11:05 foo-hdiffpatch-sequential.patch
Create an in-place patch foo-in-place.patch.
$ detools create_patch_in_place --memory-size 3000 --segment-size 500 \
tests/files/foo/old tests/files/foo/new foo-in-place.patch
Successfully created 'foo-in-place.patch' in 0.01 seconds!
$ ls -l foo-in-place.patch
-rw-rw-r-- 1 erik erik 672 feb 2 10:36 foo-in-place.patch
Create a bsdiff patch foo-bsdiff.patch, compatible with the
original bsdiff program.
$ detools create_patch_bsdiff \
tests/files/foo/old tests/files/foo/new foo-bsdiff.patch
Successfully created 'foo-bsdiff.patch' in 0 seconds!
$ ls -l foo-bsdiff.patch
-rw-rw-r-- 1 erik erik 261 feb 2 10:36 foo-bsdiff.patch
Apply the patch foo.patch to tests/files/foo/old to create
foo.new.
$ detools apply_patch tests/files/foo/old foo.patch foo.new
Successfully created 'foo.new' in 0 seconds!
$ ls -l foo.new
-rw-rw-r-- 1 erik erik 2780 feb 2 10:38 foo.new
Apply the in-place patch foo-in-place.patch to foo.mem.
$ cp tests/files/foo/in-place-3000-500.mem foo.mem
$ detools apply_patch_in_place foo.mem foo-in-place.patch
Successfully created 'foo.mem' in 0 seconds!
$ ls -l foo.mem
-rw-rw-r-- 1 erik erik 3000 feb 2 10:40 foo.mem
Apply the patch foo-bsdiff.patch to tests/files/foo/old to
create foo.new.
$ detools apply_patch_bsdiff tests/files/foo/old foo-bsdiff.patch foo.new
Successfully created 'foo.new' in 0 seconds!
$ ls -l foo.new
-rw-rw-r-- 1 erik erik 2780 feb 2 10:41 foo.new
Print information about the patch foo.patch.
$ detools patch_info foo.patch
Type: sequential
Patch size: 127 bytes
To size: 2.71 KiB
Patch/to ratio: 4.6 % (lower is better)
Diff/extra ratio: 9828.6 % (higher is better)
Size/data ratio: 0.3 % (lower is better)
Compression: lzma
Number of diffs: 2
Total diff size: 2.69 KiB
Average diff size: 1.34 KiB
Median diff size: 1.34 KiB
Number of extras: 2
Total extra size: 28 bytes
Average extra size: 14 bytes
Median extra size: 14 bytes
Fork the repository.
Install prerequisites.
pip install -r requirements.txt
Implement the new feature or bug fix.
Implement test case(s) to ensure that future changes do not break legacy.
Run the tests.
make test
Create a pull request.