[Bug 1022287] Re: negative compression ratio if list a big gzip file

[Gert van den Berg]

See page 7 of https://www.ietf.org/rfc/rfc1952.txt (ISIZE is the
relevant field)

It is an limitation of the gzip file format...

It is also documented in the gzip man page under "BUGS", with a (slow)
workaround...

One way to fix it might be to define an "extra field" with a larger
original file size... The extra fields go into the header though,
instead of the trailer, which means that it can't be correctly populated
for data piped through gzip, since the size is not known when the header
is written... (This also seems to be the suggestion here:
https://lists.gnu.org/archive/html/bug-gzip/2010-08/msg00009.html )

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Title:
  negative compression ratio if list a big gzip file

Status in gzip package in Ubuntu:
  Confirmed

Bug description:
  Please notice the uncompressed part and ratio, there should be wrong.
  uncompressed size should be more than 200GiB actually. it should be a
  overflow of integer.

  tommy at tommy-ubuntu-1110:/media/PartBackup/sdb3$ gzip -l sdb3.ntfsclone.img.gz 
           compressed        uncompressed  ratio uncompressed_name
         185808678561          4242664346 -4279.5% sdb3.ntfsclone.img
  tommy at tommy-ubuntu-1110:/media/PartBackup/sdb3$ ls -l sdb3.ntfsclone.img.gz 
  -rw-rw-r-- 1 tommy tommy 185808678561  7月  8 17:04 sdb3.ntfsclone.img.gz

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