Building an Auto-Patcher

[USC]

Hello everyone. I'm in the process of editing a PC game that would have benefited from another round of proof-reading (E.g. Line overflows and typos in the main story-line, tutorial graphics that contradict the text, clear copy & paste mishaps, etc). This consists of using janky, Japanese-only tools to unpack files, convert the extracted files into editable formats using more black-box tools, make the changes and then do everything in reverse. Not difficult, but also not the most user-friendly workflow.

Ideally, I'd like to release my work as an executable auto-patcher, so that even casual Windows users can easily install and use it. However, I've never built one before, and I fear my initial idea of writing a wrapper that applies a byte-to-byte patch to 1.5GB package files is not the best solution.

Any conceptual advice on how to go about this would be appreciated. Thanks!

[mziab]

Such a patcher can be made using NSIS and the wpatch plugin. This setup basically allows you to make a delta patch for an entire directory and package it as a nice installer. Granted, you'd have to write your own .nsi script, which takes some trial and error, and the reference patch generator for wpatch can be a bit weird at times (especially with large files), but I've used it to great success with some old PC adventure games. Moreover, once you get it right once, you have a working installer template for future projects. And if you're clever enough with the script, you can even make an uninstaller which reverses your patch, though I haven't done so myself yet. If you aren't afraid of a little tinkering and the command-line, this could be a good option.

[USC]

Ah, and here I was about to reinvent the wheel and create my own patching program.
Thanks for letting me know about this, mziab!