Bit identical HFS0 recreation

[msdos]

I've been playing with nsp-nsz converstion from some time and, although nsz offers a validation method, I always keep md5 checksum of original nsp, decompress the nsz to a temp folder and check the checksums again. They match perfectly.

But I have tried 4 different xci and the decompressed xci has a different checksum. These xci were all prior validated using https://github.com/garoxas/NX_Game_Info with the latest prod.keys and title.keys.

[nicoboss]

The current state of XCI/XCZ is like NSP/NSZ was prior to NSZ 4.3.0 which implemented bit-identical PFS0 recreation to comply with the no-intro standard. While all the files are bit identically recreated there is no such guarantee for the HFS0 file system itself. While no data is lost things like the amount of empty space between files might differ.

Bit identical HFS0 recreation is currently work in progress as part of #147. A lot of progress towards this goal was already made with the major XCI rewrite that was part of NSZ 4.6.0. Since NSZ 4.6.0 --keep can be used to keep all the HFS0 partitions including their content. With this all the difficult ground work for bit identical HFS0 recreation got laid and it's just a matter spending a few days investigating and fixing the HFS0 recreation issues. I’m more than happy to accept any pull requests contributing towards this goal.