Python 3.5 support

[aigarius]

Hi, a new bug came in to Ubuntu recently - https://bugs.launchpad.net/ubuntu/+source/python-zipstream/+bug/1480548

It seems to me that Python 3.5 slightly changed the expected symantics on file-liek objects. It looks to me that simply removing the seek() function from the zipstream.PointerIO calss could do the trick. I have not investigated if there are any other problems yet as I don't have Python 3.5 yet.

[allanlei]

Yes, it seems with 3.5 ZipFile does a check to see if the fp provided is seekable by calling fp.seek() and catches AttributeError and OSError. Since there is a non-implemented PointerIO.seek(), then the AttributeError never raises and instead raises argument error about whence.

[allanlei]

There were 2 solutions I could see

• Implement seek(offset, [whence])
• Remove seek()

Chose to go with removal since PointerIO doesn't hold data so seek() doesn't seem to fit.