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  • Hacker News
  • Worth noting ASIF's compression tradeoff also affects Spotlight indexing — since the content is opaque until mounted, you lose searchability on unmounted disk images that you'd get with a regular folder structure.
    by ARTKILL
  • I have to admit that using C syntax as a string to parse something from Python is definitely a choice. I'm not even sure I would use C structs to lay things out in C…
    by saagarjha
  • in video/image space most code we deal with day to day is still C, lots more rust plugins in gstreamer ecosystem, but 90%+ still C
    by goeiedaggoeie
  • I asked an LLM to rewrite it for me using the Python built-in struct module, and it gave me this:

       import sys
   import struct
   from collections import namedtuple
   
   # Bake the layout once into a reusable, precompiled object.
   HEADER = struct.Struct(">4sIIIQQ16sQQIIII")
   
   # struct only knows positions, not names — pair it with a namedtuple
   # to recover the named-field access that cstruct gives you for free.
   Header = namedtuple("Header", [
       "magic", "field4", "field8", "fieldC",
       "field10", "field18", "field20",
       "field30", "field38",
       "field40", "field44", "field48", "field4C",
   ])
   
   with open(sys.argv[1], "rb") as fh:
       header = Header._make(HEADER.unpack(fh.read(HEADER.size)))
   
   print(header)
    To me, this seems significantly less readable... less Pythonic, even. The printed output is also less readable.
    by quietbritishjim
  • Small self-advertisement: as an alternative to dissect.cstruct, a fun side-project of mine (C parser + C interpreter in Python) can do a very similar thing:

    https://github.com/albertz/PyCParser/blob/master/demos/disse...

    by albertzeyer
  • Image as in “filesystem snapshot” not as in “media file”.
    by ComputerGuru
  • Speaking of images (media file), I found out that iCloud double-counts storage space for rotated photos, so I need to subscribe to a higher tier just because the iPhone often can't get orientation right, especially for food photos.

    Would be nice if they moved to storing diff sidecars.

    by ValentineC
  • I like a good jaunt with IDApro as much as the next RE, but my question is what does ASIF do that Qcow2 doesn't?

    My other question is why does it take so long to copy an app out of a dmg and into /Applications. Like, just change some pointers to pointers to data on disk and shit.

    by fragmede
  • > what does ASIF do that Qcow2 doesn't

    Mount natively in macOS

    > why does it take so long to copy [...] out of a dmg

    Compression mostly. DMG contents can optionally be compressed using zlib, lzfse, or slow as molasses bzip2.

    Also Gatekeeper.

    by donatj
  • More info on how ASIF differs from the decades-old sparseimage format: https://news.ycombinator.com/item?id=44259132
    by dcrazy