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import time
from pypy.interpreter.error import oefmt
from pypy.interpreter.typedef import TypeDef
from pypy.interpreter.gateway import interp2app, unwrap_spec
from pypy.interpreter.baseobjspace import W_Root
from rpython.rlib.rarithmetic import r_uint, intmask, widen
from rpython.rlib import rbigint, rrandom, rstring
def descr_new__(space, w_subtype, __args__):
w_anything = __args__.firstarg()
x = space.allocate_instance(W_Random, w_subtype)
x = space.interp_w(W_Random, x)
W_Random.__init__(x, space, w_anything)
return x
class W_Random(W_Root):
def __init__(self, space, w_anything):
self._rnd = rrandom.Random()
self.seed(space, w_anything)
def random(self, space):
return space.newfloat(self._rnd.random())
def seed(self, space, w_n=None):
if w_n is None:
w_n = space.newint(int(time.time()))
else:
if space.isinstance_w(w_n, space.w_int):
w_n = space.abs(w_n)
else:
n = space.hash_w(w_n)
w_n = space.newint(r_uint(n))
key = []
w_one = space.newint(1)
w_two = space.newint(2)
w_thirtytwo = space.newint(32)
# 0xffffffff
w_masklower = space.sub(space.pow(w_two, w_thirtytwo, space.w_None),
w_one)
while space.is_true(w_n):
w_chunk = space.and_(w_n, w_masklower)
chunk = space.uint_w(w_chunk)
key.append(chunk)
w_n = space.rshift(w_n, w_thirtytwo)
if not key:
key = [r_uint(0)]
self._rnd.init_by_array(key)
def getstate(self, space):
state = [None] * (rrandom.N + 1)
for i in range(rrandom.N):
state[i] = space.newint(widen(self._rnd.state[i]))
state[rrandom.N] = space.newlong(self._rnd.index)
return space.newtuple(state)
def setstate(self, space, w_state):
if not space.isinstance_w(w_state, space.w_tuple):
raise oefmt(space.w_TypeError, "state vector must be tuple")
if space.len_w(w_state) != rrandom.N + 1:
raise oefmt(space.w_ValueError, "state vector is the wrong size")
w_zero = space.newint(0)
# independent of platfrom, since the below condition is only
# true on 32 bit platforms anyway
w_add = space.pow(space.newint(2), space.newint(32), space.w_None)
for i in range(rrandom.N):
w_item = space.getitem(w_state, space.newint(i))
if space.is_true(space.lt(w_item, w_zero)):
w_item = space.add(w_item, w_add)
self._rnd.state[i] = space.uint_w(w_item)
w_item = space.getitem(w_state, space.newint(rrandom.N))
index = space.int_w(w_item)
if index < 0 or index > rrandom.N:
raise oefmt(space.w_ValueError, "invalid state")
self._rnd.index = index
@unwrap_spec(k=int)
def getrandbits(self, space, k):
if k <= 0:
raise oefmt(space.w_ValueError,
"number of bits must be greater than zero")
bytes = ((k - 1) // 32 + 1) * 4
bytesarray = rstring.StringBuilder(bytes)
for i in range(0, bytes, 4):
r = self._rnd.genrand32()
if k < 32:
r >>= (32 - k)
bytesarray.append(chr(r & r_uint(0xff)))
bytesarray.append(chr((r >> 8) & r_uint(0xff)))
bytesarray.append(chr((r >> 16) & r_uint(0xff)))
bytesarray.append(chr((r >> 24) & r_uint(0xff)))
k -= 32
# little endian order to match bytearray assignment order
result = rbigint.rbigint.frombytes(
bytesarray.build(), 'little', signed=False)
return space.newlong_from_rbigint(result)
W_Random.typedef = TypeDef("Random",
__new__ = interp2app(descr_new__),
random = interp2app(W_Random.random),
seed = interp2app(W_Random.seed),
getstate = interp2app(W_Random.getstate),
setstate = interp2app(W_Random.setstate),
getrandbits = interp2app(W_Random.getrandbits),
)
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