环形缓冲区模拟模型

#!/usr/bin/env python
#encoding: utf8
#
#

import threading
from time import ctime
import time


class MyThread(threading.Thread):
    def __init__(self, func, args, name=''):
        threading.Thread.__init__(self)
        self.name = name
        self.func = func
        self.args = args

    def run(self):
        print 'create %s'%self.name
        self.res = self.func(*self.args)


class CQueue():
    def __init__(self, len):
        self.cque = []      #circle queue
        self.ppos = 0       #put position
        self.gpos = 0       #get position
        self.clen = 0       #current position
        self.tlen = len     #total length

        #init circle queue
        for i in range(len):
            self.cque.append(0)

    def get_item(self, n):
        return self.cque[n]

    def set_item(self, n, v):
        self.cque[n] = v

    def is_empty(self):
        return (self.clen == 0)

    def is_full(self):
        return (self.clen == self.tlen)

    def printst(self):
        print 'totalen=%d, clen=%d, ppos=%d, gpos=%d' % \
            (self.tlen, self.clen, self.ppos, self.gpos)
        print str(self.cque)


class Worker():
    def __init__(self, qlen):
        self.cq = CQueue(qlen)
        self.qlock = threading.Lock()
        self.cv = threading.Condition(self.qlock)

    def writer(self):
        ''' writer: who writing item to queue. '''
        while True:
            self.cv.acquire()
            print 'writer locked'
            self.cq.set_item(self.cq.ppos, 1)
            self.cq.ppos += 1
            if self.cq.ppos == self.cq.tlen:    #q is full, roll
                self.cq.ppos = 0
            self.cq.clen += 1

            self.cv.notify()
            self.cq.printst()
            self.cv.release()
            time.sleep(1)

    def reader(self):
        ''' reader who get item from queue. '''
        while True:
            self.cv.acquire()
            print 'read locked'
            while self.cq.is_empty():
                self.cv.wait()
            #read one
            print 'read one : %d' % self.cq.get_item(self.cq.gpos)
            self.cq.set_item(self.cq.gpos, 0)

            self.cq.gpos += 1
            if self.cq.gpos == self.cq.tlen: #roll
                self.cq.gpos = 0
            self.cq.clen -= 1

            #self.cq.printst()
            self.cv.release()
            time.sleep(1)

def do_work():
    ''' do my job '''
    w = Worker(10)
    w.cq.printst()
    threads = []

    #create writer
    for i in range(1):
        t = MyThread(w.writer, (), 'writer')
        threads.append(t)

    #create reader
    for i in range(2):
        t = MyThread(w.reader, (), 'reader')
        threads.append(t)

    nth = len(threads)
    for i in range(nth):
        threads[i].start()

    for i in range(nth):
        threads[i].join()

#main
if __name__ == '__main__':
    do_work()