S03C21.py

# Imports
import time

def get_lowest_bits(n: int, number_of_bits: int) -> int:
    """
    Returns the lowest "number_of_bits" bits of n.
    """
    mask = (1 << number_of_bits) - 1
    return n & mask

class MT19937:
    """
    This implementation resembles the one of the Wikipedia pseudo-code.
    """

    W, N, M, R = 32, 624, 397, 31
    A = 0x9908B0DF
    U, D = 11, 0xFFFFFFFF
    S, B = 7, 0x9D2C5680
    T, C = 15, 0xEFC60000
    L = 18
    F = 1812433253
    LOWER_MASK = (1 << R) - 1
    UPPER_MASK = get_lowest_bits(not LOWER_MASK, W)
    
    def __init__(self: object, seed: int):
        self.mt = []

        self.index = self.N
        self.mt.append(seed)
        for i in range(1, self.index):
            self.mt.append(get_lowest_bits(self.F * (self.mt[i - 1] ^ (self.mt[i - 1] >> (self.W - 2))) + i, self.W))
            
    def extract_number(self: object) -> int:
        """
        Extracts the new random number.
        """
        if self.index >= self.N:
            self.twist()

        y = self.mt[self.index]
        y ^= (y >> self.U) & self.D
        y ^= (y << self.S) & self.B
        y ^= (y << self.T) & self.C
        y ^= (y >> self.L)

        self.index += 1
        return get_lowest_bits(y, self.W)

    def twist(self: object):
        """
        Performs the twisting part of the encryption.
        """
        for i in range(self.N):
            x = (self.mt[i] & self.UPPER_MASK) + (self.mt[(i + 1) % self.N] & self.LOWER_MASK)
            x_a = x >> 1
            if x % 2 != 0:
                x_a ^= self.A

            self.mt[i] = self.mt[(i + self.M) % self.N] ^ x_a

        self.index = 0
        
def main():
	
	# Check if the numbers look random
	for i in range(10):
		print(MT19937(i).extract_number())
		
	return
	
if __name__=="__main__":
	main()