bitvec.py 文件源码

def _compute_len(param):
    mant, l = math.frexp(float(param))
    bitmask = 1L << l
    if bitmask <= param:
        raise RuntimeError('(param, l) = %r' % ((param, l),))
    while l:
        bitmask = bitmask >> 1
        if param & bitmask:
            break
        l = l - 1
    return l