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# test concurrent mutating access to a shared bytearray object
#
# MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
import _thread
# the shared bytearray
ba = bytearray()
# main thread function
def th(n, lo, hi):
for repeat in range(n):
for i in range(lo, hi):
l = len(ba)
ba.append(i)
assert len(ba) >= l + 1
l = len(ba)
ba.extend(bytearray([i]))
assert len(ba) >= l + 1
with lock:
global n_finished
n_finished += 1
lock = _thread.allocate_lock()
n_thread = 4
n_finished = 0
n_repeat = 4 # use 40 for more stressful test (uses more heap)
# spawn threads
for i in range(n_thread):
_thread.start_new_thread(th, (n_repeat, i * 256 // n_thread, (i + 1) * 256 // n_thread))
# busy wait for threads to finish
while n_finished < n_thread:
pass
# check bytearray has correct contents
print(len(ba))
count = [0 for _ in range(256)]
for b in ba:
count[b] += 1
print(count)
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