Patches using Delta Compression

[Matthiee]

Patching system with delta compression

To create smaller updates and reduce the time, UpdateLib should start using patches. These patches will be created using the VCDIFF/RFC3284 algorithm. All the patches for a version will be bundled together with metadata into a single compressed zip archive.

Existing software

• For VCDiff we can use the XDelta3 project.
• For the compressed zip we can use the SharpZipLib project.

Current zip idea/layout

• patch.zip/
  • delta/
  • delta files
  • new/
  • newly added files
  • metdata file

Metdata file

Metdata file contains pointers more information. This should also contain information about deleted files etc.

Other

The highest compression settings are currently used, might change to find a better compression/time ratio.

xdelta3 -e -f -9 -S -s original.exe updated.exe original.exe.delta For the zip inflate/deflate using level 9 will be used.

[Matthiee]

Edit we will probably use our own managed VCDiff library running on .NET Standard 2.0