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# Written by Ross Cohen
# See LICENSE.txt for license information.
import sys
try:
from os import urandom as random_string
except ImportError:
if sys.platform == 'win32':
from winrandom import winrandom as random_string
else:
dev = None
def random_string(bytes):
"""Generate a random string with the given length."""
global dev
if dev is None:
dev = open('/dev/urandom', 'r')
return dev.read(bytes)
def random_long(bits):
"""Generate a random long integer with the given number of bits."""
return string_to_long(random_string((bits+7)/8)) % (1L<<bits)
def string_to_long(s):
"""Convert a string of bytes into a long integer."""
r = 0L
for c in s:
r = (r << 8) + ord(c)
return r
def long_to_string(i, length=0):
"""Convert a long integer into a string of bytes."""
s = ''
while i > 0:
s = chr(i & 255) + s
i = i >> 8
s = '\x00' * (length - len(s)) + s
return s
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