Access to a Zip archive from multiple threads

[Markus Pöpping <markus%precipoint.de@localhost>]

Dear LibZip community,

I am trying to write code that handles zip archives with lots of
entries, in the range of 100k to 1 million. It's read-only access. So
far, it works pretty well.
Now, the big issue is, I would like to have parallel access from
multiple threads to the same archive. Obviously, zip_fopen cannot handle
this, unless I implement waiting locks.
One possible solution would be to open several instances with zip_open,
but that solution obviously costs too much time and resources: A few
seconds for each zip_open and >60 MB heap space for the directory.
The other one I perceive is to get a new handle to the archive with
fopen(), and somehow ask LibZip for the stream offset and call the
necessary decompression functions by hand. Apparently, such operations
are not really desirable, as I see *struct zip_dirent* and others are
completely private.

Is there a possible workaround that doesn't rely too much on private
implementation details, or is there any feature planned that does
facilitate this sort of operation ?

Thanks in advance,

Markus