#!/usr/bin/env python

# -*- coding: utf-8 -*-

import re,time 

def _read_cpu_usage():

        """Read the current system cpu usage from /proc/stat"""

        statfile = "/proc/stat"

        cpulist = []

        try:

                f = open(statfile, 'r')

                lines = f.readlines()

        except:

                print "ERROR: Can not open %s,The system cannot continue to run" % (statfile)

                return []

        for line in lines:

            tmplist = line.split()

            if len(tmplist) < 5:

                continue

            for b in tmplist:

                 m = re.search(r'cpu\d+',b)

                 if m is not None:

                    cpulist.append(tmplist)

        f.close()

        return cpulist

def get_cpu_usage():

        cpuusage = {}

        cpustart = {}

        cpuend = {}

        linestart = _read_cpu_usage()

        if not linestart:

                return 0

        for cpustr in linestart:

                usni=long(cpustr[1])+long(cpustr[2])+long(cpustr[3])+long(cpustr[5])+long(cpustr[6])+long(cpustr[7])+long(cpustr[4])

                usn=long(cpustr[1])+long(cpustr[2])+long(cpustr[3])

                cpustart[cpustr[0]] = str(usni)+":"+str(usn)

        sleep = 2

        time.sleep(sleep)

        lineend = _read_cpu_usage()

        if not lineend:

                return 0

        for cpustr in lineend:

                usni=long(cpustr[1])+long(cpustr[2])+long(cpustr[3])+long(cpustr[5])+long(cpustr[6])+long(cpustr[7])+long(cpustr[4])

                usn=long(cpustr[1])+long(cpustr[2])+long(cpustr[3])

                cpuend[cpustr[0]] = str(usni)+":"+str(usn)

        for line in cpustart:

                start = cpustart[line].split(':')

                usni1,usn1 = float(start[0]),float(start[1])

                end = cpuend[line].split(':')

                usni2,usn2 = float(end[0]),float(end[1])

                cpuper=(usn2-usn1)/(usni2-usni1)

                cpuusage[line] = int(100*cpuper) 

        return cpuusage 

if __name__ == '__main__':

        a = get_cpu_usage()

        print a