view roundup/anypy/random_.py @ 8264:09e8d1a4c796

docs: clarify wording, fix index, add superseder link Make superseder, messages etc. properties index entries point to the right place. Link to description of using Superseder in the original overview. fix bad wording on boolean properties.
author John Rouillard <rouilj@ieee.org>
date Wed, 08 Jan 2025 11:39:54 -0500
parents f002747b6773
children
line wrap: on
line source

# ruff: noqa: ARG001
try:
    from secrets import choice, randbelow, token_bytes

    def seed(v=None):
        pass

    is_weak = False
except ImportError:
    import os as _os
    import random as _random

    # prefer to use SystemRandom if it is available
    if hasattr(_random, 'SystemRandom'):
        def seed(v=None):
            pass

        _r = _random.SystemRandom()
        is_weak = False
    else:
        # don't completely throw away the existing state, but add some
        # more random state to the existing state
        def seed(v=None):
            # ruff: noqa: PLC0415
            import os
            import time
            _r.seed((_r.getstate(),
                     v,
                     hasattr(os, 'getpid') and os.getpid(),
                     time.time()))

        # create our own instance so we don't mess with the global
        # random number generator
        _r = _random.Random()
        seed()
        is_weak = True

    choice = _r.choice

    def randbelow(i):
        return _r.randint(0, i - 1)

    if hasattr(_os, 'urandom'):
        def token_bytes(size):
            return _os.urandom(size)
    else:
        def token_bytes(size):
            _bchr = chr if str is bytes else lambda x: bytes((x,))
            return b''.join([_bchr(_r.getrandbits(8)) for i in range(size)])

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