asar VS tarindexer

The game is using @electron/asar which isn't anything special.

Since Hop doesn't do compression, the most appropriate comparison would be to asar

https://github.com/electron/asar

It's not hard being faster than zip if you are not compressing/uncompressing.

$ npm install --engine-strict asar https://github.com/electron/asar

We just had a look at Twitch Studio for the first time. We've been using OBS so far. It looks like Twitch Studio is closed source and Twitch doesn't have a way for the community to release plugins for it. Twitch Studio is an Electron app, so I was able to reverse-engineer the source code by using asar, but unfortunately Twitch obfuscated all the code which makes it very hard to understand what's going on. Looks like we'd have to wait until Twitch Studio brings official support for developer plugins... (I hope our analysis is right, please correct us if not.)

Asar is a simple extensive archive format, it works like tar that concatenates all files together without compression, while having random access support. ~ https://github.com/electron/asar/blob/master/README.md

The bioinformatics community uses block based gzip compression (bgzip) [0]. The gzip standard allows for blocks so, using an additional index file, you can use it to seek to arbitrary locations and uncompress the block.

gzip compression is maybe not optimal now and the block segmentation reduces the efficiency even further.

Though not very standard, there is also a tar indexer program [1] that allows you to create an index on tar files to do the same.

My information is at least a couple years old so things may have changed.

[0] http://www.htslib.org/doc/bgzip.html

[1] https://github.com/devsnd/tarindexer

The pieces are there. https://github.com/devsnd/tarindexer/blob/master/tarindexer.py is a prototype of indexing and seeking a tar file in python. https://github.com/pauldmccarthy/indexed_gzip allows indexing and seeking a gzip file. If those pieces of code were combined it could give you efficient targeted file extraction, but you'd need to find a coder with enough time and motivation to fuss with it.

There exists a utility called tarindexer [0] that can be used for random access to tar files. An index text file is created (one time) that is used to record the position of the files in the tar archive. Random reads are done by loading the index file and then seeking to the location of the file in question.

For random access to gzip'd files, bgzip [1] can be used. bgzip also uses an index file (one time creation) that is used to record key points for random access.

[0] https://github.com/devsnd/tarindexer

[1] http://www.htslib.org/doc/bgzip.html