| 799 | |
| 800 | |
| 801 | class NullBitmap(Bitmap): |
| 802 | |
| 803 | def __getitem__(self, index): |
| 804 | self._check_index(index) |
| 805 | if self.view is None: |
| 806 | return True |
| 807 | return super().__getitem__(index) |
| 808 | |
| 809 | @classmethod |
| 810 | def from_buffer(cls, buf, offset, length): |
| 811 | """ |
| 812 | Create a null bitmap from a Buffer (or None if missing, |
| 813 | in which case all values are True). |
| 814 | """ |
| 815 | if buf is None: |
| 816 | return cls(buf, offset, length) |
| 817 | return super().from_buffer(buf, offset, length) |
| 818 | |
| 819 | |
| 820 | KeyValue = namedtuple('KeyValue', ('key', 'value')) |