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Python - map_file error for large file sizes #730

Closed GoogleCodeExporter closed 8 years ago

GoogleCodeExporter commented 8 years ago 
What steps will reproduce the problem?
1.Python bindings
2. call torrent_info.map_file(idx,0,size)
3. if size is > 2GB then error :
OverflowError: bad numeric conversion: positive overflow

What is the expected output? What do you see instead?
Should work for any file size,
works without problem for sizes < 2 GB

What version of the product are you using? On what operating system?
1.0.4.0
but same error for 0.16... (in Ubuntu 14.04 repos)

Please provide any additional information below.
Platform: Ubuntu 14.04 64-bits

Original issue reported on code.google.com by ivan.zde...@gmail.com on 8 Apr 2015 at 8:48

GoogleCodeExporter commented 8 years ago 
the map_file() function was intended to map to peer_requests (as the return 
type indicates). A peer request may not be larger than 16 kiB. The reason to 
not trivially extend the width of the return types is that the peer_requests 
type is actually used internally as well, and widening would use more memory 
and be less efficient (in fact, it should probably be shrunk).

I'm actually surprised python gave such a good error message. I imagine in c++ 
you would just get a wrapped signed integer.

The way examples/dump_torrent gets around this (really though, it isn't trying 
to do the same thing as you do), is to call map_file() twice, once for the 
first byte and once for the last. It's just looking to see which pieces they 
fall into.

I'm inclined to improve the documentation and close this ticket, unless you 
have some compelling argument for introducing a new type, different from 
peer_request, with wider byte counters in it, as the return type for map_file().

Original comment by arvid.no...@gmail.com on 8 Apr 2015 at 11:41

GoogleCodeExporter commented 8 years ago 
Thanks for quick response and explanation.
I agree - it was misunderstanding of map_file function, from my side,  in fact 
piece index and offset is enough for me,  because size I already know.
So please if you can close this issue,  

Ivan

Original comment by ivan.zde...@gmail.com on 9 Apr 2015 at 8:35

GoogleCodeExporter commented 8 years ago

Original comment by arvid.no...@gmail.com on 10 Apr 2015 at 3:27