blob: bc3dc1ea07c2bb388edf926ebb2b544635e009e3 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
|
# Return a next value in a reasonably MT-safe manner
import random
random.seed()
class Integer:
def __init__(self, maximum, increment=256):
self.__maximum = maximum
if increment >= maximum:
increment = maximum
self.__increment = increment
self.__threshold = increment//2
e = random.randrange(self.__maximum - self.__increment)
self.__bank = list(range(e, e+self.__increment))
def __repr__(self):
return '%s(%d, %d)' % (
self.__class__.__name__,
self.__maximum,
self.__increment
)
def __call__(self):
v = self.__bank.pop(0)
if v % self.__threshold:
return v
else:
# this is MT-safe unless too many (~ increment/2) threads
# bump into this code simultaneously
e = self.__bank[-1]+1
if e > self.__maximum:
e = 0
self.__bank.extend(range(e, e+self.__threshold))
return v
|
