Fulfill Martin's request to use try/except rather than a "look before
you leap" approach. Makes the early call to os.urandom() unnecessary.
diff --git a/Lib/random.py b/Lib/random.py
index e6f6e4b..46a1b1f 100644
--- a/Lib/random.py
+++ b/Lib/random.py
@@ -44,6 +44,8 @@
from math import log as _log, exp as _exp, pi as _pi, e as _e
from math import sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin
from math import floor as _floor
+from os import urandom as _urandom
+from binascii import hexlify as _hexlify
__all__ = ["Random","seed","random","uniform","randint","choice","sample",
"randrange","shuffle","normalvariate","lognormvariate",
@@ -59,13 +61,6 @@
BPF = 53 # Number of bits in a float
RECIP_BPF = 2**-BPF
-try:
- from os import urandom as _urandom
- from binascii import hexlify as _hexlify
- _urandom(1) # verify that urandom is implemented
-except (ImportError, NotImplementedError):
- _urandom = None
-
# Translated by Guido van Rossum from C source provided by
# Adrian Baddeley. Adapted by Raymond Hettinger for use with
@@ -111,11 +106,11 @@
"""
if a is None:
- if _urandom is None:
+ try:
+ a = long(_hexlify(_urandom(16)), 16)
+ except NotImplementedError:
import time
a = long(time.time() * 256) # use fractional seconds
- else:
- a = long(_hexlify(_urandom(16)), 16)
super(Random, self).seed(a)
self.gauss_next = None
@@ -620,11 +615,11 @@
"""
if a is None:
- if _urandom is None:
+ try:
+ a = long(_hexlify(_urandom(16)), 16)
+ except NotImplementedError:
import time
a = long(time.time() * 256) # use fractional seconds
- else:
- a = long(_hexlify(_urandom(16)), 16)
if not isinstance(a, (int, long)):
a = hash(a)
@@ -759,14 +754,10 @@
def random(self):
"""Get the next random number in the range [0.0, 1.0)."""
- if _urandom is None:
- raise NotImplementedError('Cannot find hardware entropy source')
return (long(_hexlify(_urandom(7)), 16) >> 3) * RECIP_BPF
def getrandbits(self, k):
"""getrandbits(k) -> x. Generates a long int with k random bits."""
- if _urandom is None:
- raise NotImplementedError('Cannot find hardware entropy source')
if k <= 0:
raise ValueError('number of bits must be greater than zero')
if k != int(k):