tmp.py

#!/usr/bin/env python3
# -*- coding: UTF-8 -*-
# Copyright (c) 2015 Netpas Tech-Development Co. Ltd.

import shlex
import ipaddress


DIFF = 10  # 毫秒
DEFAULT_NETMASK = ipaddress.IPv4Address('255.255.255.0')


def parse_line(line):
    """分析一行

    有效的行形如： 219.141.136.101 (89.1 ms)
    分析后返回 (IPv4Address, int) 2-tuple
    """
    segs = shlex.shlex(line)
    segs.wordchars += '.'
    segs.whitespace += '()'
    result = list(segs)
    if len(result)!=3 and result[-1]=='ms':
        return None
    ipaddr = ipaddress.IPv4Address(result[0])
    delay = int(result[1])
    return ipaddr, delay


def _get_network(ipaddr):
    network = ipaddress.IPv4Address(int(ipaddr) & int(DEFAULT_NETMASK))
    network = ipaddress.IPv4Network(str(network) + '/' + str(DEFAULT_NETMASK))
    return network


def compare(last, current):
    """如果 last 的 IP 地址与 current 的 IP 地址在同一网段，
    且延时相差不超过 DIFF 毫秒，"""
    if not last:
        return [current]
    network = _get_network(last[0])
    if current[0] not in network:
        return [last, current]
    if abs(current[1]-last[1]) < DIFF:
        return [current]
    return [last, current]


def parse_file(filename):
    last = None
    with open(filename, "r", encoding="utf8") as f:
        line = f.readline(256)
        current = parse_line(line)
        if current:
            items = compare(last, current)