number.py 文件源码

def getRandomInteger(N, randfunc=None):
    """getRandomInteger(N:int, randfunc:callable):long
    Return a random number with at most N bits.

    If randfunc is omitted, then Random.new().read is used.

    This function is for internal use only and may be renamed or removed in
    the future.
    """
    if randfunc is None:
        _import_Random()
        randfunc = Random.new().read

    S = randfunc(N>>3)
    odd_bits = N % 8
    if odd_bits != 0:
        char = ord(randfunc(1)) >> (8-odd_bits)
        S = bchr(char) + S
    value = bytes_to_long(S)
    return value