Bumping the minor version of the file format to '2'.
The "ino" field is only interesting for hardlinks, so we can save space
by not exporting it for other entries.
The hlink count will be interesting later on when I implement tracking
of shared data between directories. It's currently ignored on import.
The "nlink" field makes the "hlnkc" field redundant, but let's keep
including that field anyway for backwards compatibility.
Unfortunately, there wasn't a single bit free in struct dir.flags, so I
had to increase its size to 16 bit. This commit is just the initial
preparation, there's still a few things to do:
- Add "extended information" cli flag to enable/disable this
functionality.
- Export and import extended information when requested
- Do something with the data.
I also did a few memory measurements on a file list with 12769842 items:
before this commit: 1.239 GiB
without extended info: 1.318 GiB
with extended info: 1.698 GiB
It's surprising what adding a single byte to a struct can do to the
memory usage. :(
!WARNING! The export option is experimental, and the file format is not
final. I make no promise that a future version of ncdu will be able to
read the current format. There's also quite a few TODO's left.
