bitmap.py

def cast(v):
    if isinstance(v, bitmap):
        return v.i
    else:
        return v

class bitmap(object):
    __slots__ = ("i",)

    def __init__(self, i = 0):
        self.i = i

    @property
    def bits(self):
        i = self.i
        while i:
            yield i & 1
            i >>= 1

    def __iter__(self):
        for i, bit in enumerate(self.bits):
            if bit:
                yield i

    def __setitem__(self, n, bit):
        if bit:
            self.i |= 1 << n
        else:
            low_mask = (1 << n) - 1
            i = self.i
            n += 1
            high = i >> n << n
            self.i = high | i & low_mask

    def __str__(self):
        res = ""
        for b in self.bits:
            res = ("1" if b else "0") + res
        if not res:
            res = "0"
        return res

    def __and__(self, v):
        return bitmap(self.i & cast(v))

b = bitmap(0xAA)

def p():
    global b
    print(list(b))
    print(b)


p()

b[20] = 1

p()

b[6] = 1

p()

b[8] = 1

p()

b[7] = 0

p()

b[80] = 1

p()

b[200] = 1

p()

b = b & 3

p()

b = b & bitmap(3)

p()