#!/usr/bin/python3.3
import os, threading
try:
    from cPickle import Pickler, Unpickler
except ImportError:
    from pickle import Pickler, Unpickler

def unpickler(load, ack):
    while 1:
        try:
            load() # C implementation hangs on Python 3
                   # when it processes a message of 4096*n+1 bytes
        except EOFError:
            break
        ack()

lock = threading.Lock()
lock.acquire()
r, w = os.pipe()
stdout = os.fdopen(w, 'wb')
pickler = Pickler(stdout, 2)
load = Unpickler(os.fdopen(r, 'rb')).load
t = threading.Thread(target=unpickler, args=(load, lock.release))
t.daemon = 1
t.start()
for i in 4085, 4086, 4088, 4087:
    os.write(2, (u"dump(%u)\n" % i).encode())
    pickler.dump(' ' * i)
    stdout.flush()
    pickler.clear_memo()
    lock.acquire()
stdout.close()
t.join()