Better exclude_address function in ipaddress.py

Commencez dans ipaddress.py, au niveau de address_exclude, et examinez les chemins existants de subnets() et summarize_address_range(). Comparez l’approche proposée fondée sur des plages d’entiers avec le comportement actuel, en préservant les résultats réseau démontrés tout en corrigeant le problème de performances signalé.

Feature or enhancement

Increase the speed of exclude_address by treating IPs as integer ranges making exclude_address O(1).

Pitch

Currently exclude_address will take a subnet and split it by calling subnets()

import ipaddress
>>> ip = ipaddress.IPv4Network('10.0.0.0/8')
>>> [i for i in ip.subnets()]
[IPv4Network('10.0.0.0/9'), IPv4Network('10.128.0.0/9')]

each time it is split, it checks which one contains the subnet being excluded and splits again.
This ends up being a lot of work.

Instead I propose we can use the fact that IPs are represented as integers behind the scene

For a given subnet, it can be thought of as an integer range between its network and broadcast address

>>> ip.network_address._ip
167772160
>>> ip.broadcast_address._ip
184549375

Given these can be treated as an integer range, excluding is just removing the range integers you wish to exclude

>>> [i for i in ipaddress.summarize_address_range(
    ipaddress.IPv4Address(
        ip.network_address._ip),
        ipaddress.IPv4Address(exclude_ip.network_address._ip-1
))]
[IPv4Network('10.0.0.0/22')]

>>> [i for i in ipaddress.summarize_address_range(
    ipaddress.IPv4Address(
        exclude_ip.broadcast_address._ip)+1,
        ipaddress.IPv4Address(ip.broadcast_address._ip
))]
[IPv4Network('10.0.5.0/24'), IPv4Network('10.0.6.0/23'), IPv4Network('10.0.8.0/21'), IPv4Network('10.0.16.0/20'), IPv4Network('10.0.32.0/19'), IPv4Network('10.0.64.0/18'), IPv4Network('10.0.128.0/17'), IPv4Network('10.1.0.0/16'), IPv4Network('10.2.0.0/15'), IPv4Network('10.4.0.0/14'), IPv4Network('10.8.0.0/13'), IPv4Network('10.16.0.0/12'), IPv4Network('10.32.0.0/11'), IPv4Network('10.64.0.0/10'), IPv4Network('10.128.0.0/9')]

>>> sorted([i for i in ip.address_exclude(
    ipaddress.IPv4Network('10.0.4.0/24'
))])
[IPv4Network('10.0.0.0/22'), IPv4Network('10.0.5.0/24'), IPv4Network('10.0.6.0/23'), IPv4Network('10.0.8.0/21'), IPv4Network('10.0.16.0/20'), IPv4Network('10.0.32.0/19'), IPv4Network('10.0.64.0/18'), IPv4Network('10.0.128.0/17'), IPv4Network('10.1.0.0/16'), IPv4Network('10.2.0.0/15'), IPv4Network('10.4.0.0/14'), IPv4Network('10.8.0.0/13'), IPv4Network('10.16.0.0/12'), IPv4Network('10.32.0.0/11'), IPv4Network('10.64.0.0/10'), IPv4Network('10.128.0.0/9')]

Previous discussion

https://discuss.python.org/t/ipaddress-py-exclude-address-speed-up/19445