Kernel log时间转换

https://www.cnblogs.com/atlas2016/p/7235095.html
对上面网页的转换做了修改，增加每次读到行android time就刷新基础计算时间的功能，保证以上次最近的android time时间为基础。

import time
import datetime
import sys
import getopt
import os

a_time = None
s_second = None
s_microsecond = None
abs_time = 0.0
inputfile = None
outputfile = None

def usage():
    print('''Help Information:
             -h, --help:        Show help information
             -i, --inputfile:   input file  to parse
             -o, --outputfile:  output file parsed
                        ''')

def calc_delta(stream):
    global s_second
    global s_microsecond
    global a_time
    global outfile
    begin_index = None
    end_index = None
    delta_second = 0
    delta_mircosecond = 0
    delta_time = 0
    d_time = None
    new_line = None
    for line in stream:
        if line:
            if 'android time' in line:
                update_time_reference(line)
            try:
                begin_index =  line.index('[')
                end_index = line[begin_index+1:].index(']')+begin_index+1
                time_string = line[begin_index + 1