chess-info

#!/usr/bin/python3
class Coder:
    def __init__(self, log2_squarec):
        self.log2_squarec = log2_squarec
        self.squarec = 2**log2_squarec
        self.masks = self._make_masks()
    def _make_masks(self):
        result = []
        for i in reversed(range(self.log2_squarec)):
            result.append(2**2**i * (2**self.squarec-1) // (2**2**i+1))
        return result
    def encode(self, board, value):
        assert 0 <= value < self.squarec
        yuck = self.decode(board)
        spice = yuck ^ value
        return board ^ (2 ** spice)
    def decode(self, board):
        cooked = 0
        for i in self.masks:
            cooked *= 2
            cooked += pop(board & i) % 2
        return cooked
def pop(x):
    count = 0
    while x:
        if x % 2 == 1:
            count += 1
        x //= 2
    return count
def assert_working(coder):
    from random import choice, randrange
    original = randrange(coder.squarec)
    board = int(''.join(choice(['0', '1']) for _ in range(coder.squarec)), 2)
    encoded = coder.encode(board, original)
    decoded = coder.decode(encoded)
    assert pop(encoded ^ board) == 1
    assert original == decoded
def test(coder, timec=1000):
    for i in range(timec):
        assert_working(coder)
    print(timec, "random tests completed successfully!")
coder = Coder(log2_squarec=6)
test(coder)