<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">#  Copyright 2011 Sybren A. StГјvel &lt;sybren@stuvel.eu&gt;
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      https://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

"""Functions for parallel computation on multiple cores.

Introduced in Python-RSA 3.1.

.. note::

    Requires Python 2.6 or newer.

"""

import multiprocessing as mp
from multiprocessing.connection import Connection

import rsa.prime
import rsa.randnum


def _find_prime(nbits: int, pipe: Connection) -&gt; None:
    while True:
        integer = rsa.randnum.read_random_odd_int(nbits)

        # Test for primeness
        if rsa.prime.is_prime(integer):
            pipe.send(integer)
            return


def getprime(nbits: int, poolsize: int) -&gt; int:
    """Returns a prime number that can be stored in 'nbits' bits.

    Works in multiple threads at the same time.

    &gt;&gt;&gt; p = getprime(128, 3)
    &gt;&gt;&gt; rsa.prime.is_prime(p-1)
    False
    &gt;&gt;&gt; rsa.prime.is_prime(p)
    True
    &gt;&gt;&gt; rsa.prime.is_prime(p+1)
    False

    &gt;&gt;&gt; from rsa import common
    &gt;&gt;&gt; common.bit_size(p) == 128
    True

    """

    (pipe_recv, pipe_send) = mp.Pipe(duplex=False)

    # Create processes
    try:
        procs = [mp.Process(target=_find_prime, args=(nbits, pipe_send)) for _ in range(poolsize)]
        # Start processes
        for p in procs:
            p.start()

        result = pipe_recv.recv()
    finally:
        pipe_recv.close()
        pipe_send.close()

    # Terminate processes
    for p in procs:
        p.terminate()

    return result


__all__ = ["getprime"]

if __name__ == "__main__":
    print("Running doctests 1000x or until failure")
    import doctest

    for count in range(100):
        (failures, tests) = doctest.testmod()
        if failures:
            break

        if count % 10 == 0 and count:
            print("%i times" % count)

    print("Doctests done")
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