Packer.pack_uhyper(): Fixes needed to properly pack unsigned 64 bit

warsaw · warsaw · commit 1d0fe31d7e4d · 1997-05-29T21:01:35.000Z
longs where the top bit is set.  First, change the masks so that they
are `L' longs, otherwise the sign bits will get propagated to the
result.  Next, do not coerce to int before sending to pack_uint()
otherwise Python will generate an OverflowError.  Here is a test
program that fails without the patch, but now succeeds:

import xdrlib

addr = (132, 151, 1, 71)
uint = 0L
for a in addr:
    uint = (uint &lt;&lt; 8) | a

ulong64 = uint &lt;&lt; 32

p = xdrlib.Packer()
p.pack_uhyper(ulong64)
buf = p.get_buffer()
u = xdrlib.Unpacker(buf)
ulong64prime = u.unpack_uhyper()

if ulong64 == ulong64prime:
    print 'okay'
else:
    print 'bogus'

print ulong64, ulong64prime
diff --git a/Lib/xdrlib.py b/Lib/xdrlib.py
@@ -55,8 +55,8 @@ def pack_bool(self, x):
 	else: self.__buf = self.__buf + '\0\0\0\0'
 
     def pack_uhyper(self, x):
-	self.pack_uint(int(x>>32 & 0xffffffff))
-	self.pack_uint(int(x & 0xffffffff))
+	self.pack_uint(x>>32 & 0xffffffffL)
+	self.pack_uint(x & 0xffffffffL)
 
     pack_hyper = pack_uhyper
 
