[Patches] [ python-Patches-576327 ] zipfile when sizeof(long) == 8

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Patches item #576327, was opened at 2002-07-02 07:11
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Category: Library (Lib)
Group: Python 2.2.x
Status: Open
Resolution: None
Priority: 5
Submitted By: The Written Word (Albert Chin) (tww-china)
Assigned to: Nobody/Anonymous (nobody)
Summary: zipfile when sizeof(long) == 8

Initial Comment:
This bug also applies to Python 2.0.x and 2.1.x (most
likely every version).

When sizeof (long) == 8, like on Tru64 UNIX,
zipfile.testzip () fails due to a CRC error. The
problem is that in Lib/zipfile.py:
  crc = binascii.crc32(bytes)
converts the 32-bit binascii.crc32() return value to a
64-bit value (crc). We need to force crc to remain a
32-bit value. Attached is a patch though maybe someone
else can think of something better.


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>Comment By: Tim Peters (tim_one)
Date: 2002-07-02 10:44

Message:
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I believe you're having a problem, but I can't tell what it is.  
Exactly how does zipfile.testzip() fail?  What did it get and 
what did it expect?

It's not possible to "force crc to remain a 32-bit value" on a 64-
bit box with sizeof(long)==8 -- Python doesn't have any 32-bit 
type on such a box.  So it seems most likely that some 32-
bit value either is or isn't getting sign-extended when this 
fails, but I can't tell from the report which of the disagreeing 
values that may be, or which it *should* be.

IOW, we need more info about how this fails.  If you're 
hacking the result of binascii.crc32() and calling that "a fix", 
chances seem high that the correct fix lies in changing what 
crc32() returns.  But not yet enough info here to say.

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