mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-23 21:11:08 +00:00
bc8df6de31
* [pre-commit.ci] pre-commit autoupdate updates: - [github.com/astral-sh/ruff-pre-commit: v0.2.2 → v0.3.2](https://github.com/astral-sh/ruff-pre-commit/compare/v0.2.2...v0.3.2) - [github.com/pre-commit/mirrors-mypy: v1.8.0 → v1.9.0](https://github.com/pre-commit/mirrors-mypy/compare/v1.8.0...v1.9.0) * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
51 lines
1.7 KiB
Python
51 lines
1.7 KiB
Python
"""
|
|
In a multi-threaded download, this algorithm could be used to provide
|
|
each worker thread with a block of non-overlapping bytes to download.
|
|
For example:
|
|
for i in allocation_list:
|
|
requests.get(url,headers={'Range':f'bytes={i}'})
|
|
"""
|
|
|
|
from __future__ import annotations
|
|
|
|
|
|
def allocation_num(number_of_bytes: int, partitions: int) -> list[str]:
|
|
"""
|
|
Divide a number of bytes into x partitions.
|
|
:param number_of_bytes: the total of bytes.
|
|
:param partitions: the number of partition need to be allocated.
|
|
:return: list of bytes to be assigned to each worker thread
|
|
|
|
>>> allocation_num(16647, 4)
|
|
['1-4161', '4162-8322', '8323-12483', '12484-16647']
|
|
>>> allocation_num(50000, 5)
|
|
['1-10000', '10001-20000', '20001-30000', '30001-40000', '40001-50000']
|
|
>>> allocation_num(888, 999)
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: partitions can not > number_of_bytes!
|
|
>>> allocation_num(888, -4)
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: partitions must be a positive number!
|
|
"""
|
|
if partitions <= 0:
|
|
raise ValueError("partitions must be a positive number!")
|
|
if partitions > number_of_bytes:
|
|
raise ValueError("partitions can not > number_of_bytes!")
|
|
bytes_per_partition = number_of_bytes // partitions
|
|
allocation_list = []
|
|
for i in range(partitions):
|
|
start_bytes = i * bytes_per_partition + 1
|
|
end_bytes = (
|
|
number_of_bytes if i == partitions - 1 else (i + 1) * bytes_per_partition
|
|
)
|
|
allocation_list.append(f"{start_bytes}-{end_bytes}")
|
|
return allocation_list
|
|
|
|
|
|
if __name__ == "__main__":
|
|
import doctest
|
|
|
|
doctest.testmod()
|