> On 5 May 2016, at 13:13, Stephen J. Butler <stephen.but...@gmail.com> wrote: > > Those files are compressed by the filesystem. In HFS+/MacOS Extended that > means that the data fork is empty and the file contents are stored in the > resource fork or extended attributes structure. > > http://wiki.sleuthkit.org/index.php?title=HFS#HFS.2B_File_Compression > > If it's in the extended attributes, then it's part of the file metadata (like > name, timestamps, etc), whereas Finder is probably using the size of the > datafork to arrive at 0 bytes. If you get the afsctool (from MacPorts for > example) then you can get all sorts of detailed info:
/Applications/Xcode.app/Contents/Developer/Documentation/DocSets/com.apple.adc.documentation.watchOS.docset/Contents/Resources/Tokens/C/tag/-/objc_cache.xml has indeed 2 extended attributes: com.apple.quarantine and com.apple.decmpfs. The problem: xattr refuses to show com.apple.decmpfs - even shamelessly lies: “No such xattr: com.apple.decmpfs”. Good news: listxattr,getxattr do not lie (with XATTR_SHOWCOMPRESSION). My own tool shows: com.apple.decmpfs = 895 bytes inline starting with: ‘cmpf’, 3, 0x7d5 = 2005 = uncompressed size, … (small endian ints). The sum of all decmpfs in the folder is 4057 bytes - still no idea how Finder gets its: “29 KB on disk” . Kind regards, Gerriet. _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
