[FEATURE]: Better progress for compressed archives

[bryceschober]

Is your feature request related to a problem? Please describe.

The progress output when writing compressed images files quickly progresses to 99% and then pauses there while the rest of the disk is being written.

Describe the solution you would like to see implemented

I've seen this issue comment noting that this is expected behavior for compressed archives. On the other hand, I get the correct uncompressed size from the output of both gzip -l my_os.img.gz and zstd -vl my_os.img.zstd, and it seems that rpi imager could use the equivalent functionality...

Yeah, I know, I'm a programmer too. It's easy to say in one sentence of english. Implementing is another thing entirely. 😄

Describe alternatives you've considered

Live with uninformative progress display, or decompress it first. 😒

Additional context

None

Version

1.9.0

[lurch]

I get the correct uncompressed size from the output of both gzip -l my_os.img.gz

Unfortunately gzip only stores the uncompressed filesize modulo 4GB; so if you have a 5GB disk-image compressed with gzip, gzip -l would report it as 1GB 🙁