Return prefix length from the bitwise netmask. Args: ip_int: An integer, the netmask in expanded bitwise format Returns: An integer, the prefix length. Raises: ValueError: If the input intermingles zeroes & ones
(cls, ip_int)
| 438 | |
| 439 | @classmethod |
| 440 | def _prefix_from_ip_int(cls, ip_int): |
| 441 | """Return prefix length from the bitwise netmask. |
| 442 | |
| 443 | Args: |
| 444 | ip_int: An integer, the netmask in expanded bitwise format |
| 445 | |
| 446 | Returns: |
| 447 | An integer, the prefix length. |
| 448 | |
| 449 | Raises: |
| 450 | ValueError: If the input intermingles zeroes & ones |
| 451 | """ |
| 452 | trailing_zeroes = _count_righthand_zero_bits(ip_int, |
| 453 | cls.max_prefixlen) |
| 454 | prefixlen = cls.max_prefixlen - trailing_zeroes |
| 455 | leading_ones = ip_int >> trailing_zeroes |
| 456 | all_ones = (1 << prefixlen) - 1 |
| 457 | if leading_ones != all_ones: |
| 458 | byteslen = cls.max_prefixlen // 8 |
| 459 | details = ip_int.to_bytes(byteslen, 'big') |
| 460 | msg = 'Netmask pattern %r mixes zeroes & ones' |
| 461 | raise ValueError(msg % details) |
| 462 | return prefixlen |
| 463 | |
| 464 | @classmethod |
| 465 | def _report_invalid_netmask(cls, netmask_str): |
no test coverage detected