| Rachit Shrivastava | 8e435b4 | 2017-08-08 23:15:26 -0400 | [diff] [blame] | 1 | from bitstring import BitArray |
| 2 | import structlog |
| 3 | |
| 4 | log = structlog.get_logger() |
| 5 | |
| 6 | class IndexPool(object): |
| 7 | def __init__(self, max_entries, offset): |
| 8 | self.max_entries = max_entries |
| 9 | self.offset = offset |
| 10 | self.indices = BitArray(self.max_entries) |
| 11 | |
| 12 | def get_next(self): |
| 13 | try: |
| 14 | _pos = self.indices.find('0b0') |
| 15 | self.indices.set(1, _pos) |
| 16 | return self.offset + _pos[0] |
| 17 | except IndexError: |
| 18 | log.info("exception-fail-to-allocate-id-all-bits-in-use") |
| 19 | return None |
| 20 | |
| 21 | def release(self, index): |
| 22 | index -= self.offset |
| 23 | _pos = (index,) |
| 24 | try: |
| 25 | self.indices.set(0, _pos) |
| 26 | except IndexError: |
| 27 | log.info("bit-position-{}-out-of-range".format(index)) |
| 28 | |
| 29 | #index or multiple indices to set all of them to 1 - need to be a tuple |
| 30 | def pre_allocate(self, index): |
| 31 | if(isinstance(index, tuple)): |
| 32 | _lst = list(index) |
| 33 | for i in range(len(_lst)): |
| 34 | _lst[i] -= self.offset |
| 35 | index = tuple(_lst) |
| 36 | self.indices.set(1, index) |