From NSIS Wiki
|Author: joost (talk, contrib)|
It calculates the difference between two (or more) similar files: a new version and several old versions. When you release a new version, you might want to offer a patch update to the users, instead of including the entire file again. So you include the small patch file generated by VPatch in your installation, together with the VPatch runtime DLL for NSIS (which is 8 KB), and you save your users a lot of downloading.
VPatch is a NSIS plugin written by Koen van de Sande.
The nsisPatchGen utility recursively compares two directory structures looking for changes to the files and subdirectories. It produces an NSIS include file containing functions that will perform a patch upgrade from the original structure to the new.
nsisPatchGen uses the VPatch genpat.exe utility to generate patch files, and calls VPatch plugin function calls from the generated NSIS file.
nsisPatchGen can be downloaded from: