Author: Amaury Forgeot d'Arc <amaur...@gmail.com>
Branch: py3k
Changeset: r49347:7ea6a7e448e0
Date: 2011-11-11 21:48 +0100
http://bitbucket.org/pypy/pypy/changeset/7ea6a7e448e0/
Log: Fix _random.get_randbits()
diff --git a/pypy/module/_random/interp_random.py
b/pypy/module/_random/interp_random.py
--- a/pypy/module/_random/interp_random.py
+++ b/pypy/module/_random/interp_random.py
@@ -91,11 +91,11 @@
raise OperationError(space.w_ValueError, strerror)
needed = (k - 1) // rbigint.SHIFT + 1
result = rbigint.rbigint([rbigint.NULLDIGIT] * needed, 1)
- for i in range(needed - 1):
- # This loses some random digits, but not too many since SHIFT=31
- value = self._rnd.genrand32()
+ for i in range(needed):
+ # This wastes some random digits, but not too many since SHIFT=31
+ value = self._rnd.genrand32() & rbigint.MASK
if i < needed - 1:
- result.setdigit(i, value & rbigint.MASK)
+ result.setdigit(i, value)
else:
result.setdigit(i, value >> ((needed * rbigint.SHIFT) - k))
return space.newlong_from_rbigint(result)
diff --git a/pypy/module/_random/test/test_random.py
b/pypy/module/_random/test/test_random.py
--- a/pypy/module/_random/test/test_random.py
+++ b/pypy/module/_random/test/test_random.py
@@ -98,6 +98,7 @@
for n in range(10, 1000, 15):
k = rnd.getrandbits(n)
assert 0 <= k < 2 ** n
+ assert rnd.getrandbits(30) != 0 # Fails every 1e10 runs
def test_subclass(self):
import _random
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