os作业３：银行家算法

银行家算法就是避免死锁。每次分配资源后检查是否存在能够存在一个平稳结束的序列。　不会引起死锁。　　思想就是这么简单。。代码写的一般。。忽略～～～

#coding=utf-8import random,timedef generateName():    global name    t=name    name=chr(ord(name)+1)    return tclass Resource:    def __init__(self,tname,tnumber):        self.name=tname        self.number=tnumberdef init():    global n,name,p    ############################################################    n=raw_input('how many Resource ? (2~4 suggested):')    n=int(n,10)    print 'n=',n    ###############    name='a'    ############################################################    p=raw_input('how many process ?(1~3 suggested):')    p=int(p,10)    print 'p=',pdef initDS():    global n,p,Available,Max,Allocation,Need,Finish    #produce Available matrix    Available=[]    for i in xrange(n):        Available.append(Resource(tname=generateName(),tnumber=random.randint(10,20)))        print 'Generate Resource: name=%s,resource=%d'%(Available[i].name,Available[i].number)    #produce Max matrix    Max=[]    #a process need a resource  <= 6    print '-------------------------------------'    print 'Max matrix:'    for i in range(p):        temp=[]        for j in range(n):            temp.append(random.randint(0,6))        Max.append(temp)        print 'process %d need resource '%i,temp        del temp    #produce Allocation    print '-------------------------------------'    print 'Allocation matrix'    Allocation=[]    for i in range(p):        temp=[]        for j in range(n):            temp.append(0)        Allocation.append(temp)        print 'process %d get resource '%i,temp        del temp    #produce Need matrix    print '-------------------------------------'    print 'Need matrix:'    Need=[]    for i in range(p):        temp=[]        for j in range(n):            temp.append(Max[i][j]-Allocation[i][j])        Need.append(temp)        print 'process %d need resource '%i,temp        del temp    print '-------------------------------------'    Finish=[]    for i in range(p):        Finish.append(False)def safeCheck(targetProcess,targetResource):    #    global n,p,Available,Max,Allocation,Need,Finish    #print 'in the safe Checking!'    #print 'work:'    work=[]    #copy Available to work    for i in range(n):        work.append(Available[i].number)    #print work    finish=[]    for i in range(p):        finish.append(Finish[i])    #print finish    #print 'need:'    need=[]    for i in range(p):        temp=[]        for j in range(n):            temp.append(Need[i][j])        need.append(temp)        #print temp        del temp    #---------------------------------    #---------------------------------    s=0 # s from 0 --- p-1    count=0    while True:        #print '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>'        #print '>>>>>>count=%d>>s=%d>>>>>>'%(count,s)        alldone=1        for i in range(p):            if finish[i]==False:                alldone=0                break        if alldone==1:            #print 'alldone'            return True        if(count>p):            print '[-] Dead Lock !'            return False            break        if finish[s]==True:            count+=1            s=(s+1)%p            continue        tflag=1        for i in range(n):            if need[s][i]>work[i]:                tflag=0        if tflag==1:#have enough resource            #do the job and release the resource            #release            #print 'doing s=%d'%s            for i in range(n):                work[i]+=Allocation[s][i]            finish[s]=True            '''            print 'test in the safe checking !'            print s,'Done!'            print 'work',work            print 'finish',finish            '''            count=0            #print 'finish %d and count=%d -------------------'%(s,count)        else:            #don nothing            count+=1            #print 'can\'t do the %d and count =%d'%(s,count)        s=(s+1)%p#------------------------------------------------------------------------------def query():    global n,p,Available,Max,Allocation,Need,Finish    #Resource    print '-------------------------------------'    for i in xrange(n):        print 'Available Resource %s,resource=%d'%(Available[i].name,Available[i].number)    print '-------------------------------------'    print 'Max matrix:'    for i in range(p):        print 'process %d need resource '%i,Max[i]    #produce Allocation    print '-------------------------------------'    print 'Allocation matrix:'    for i in range(p):        print 'process %d get resource '%i,Allocation[i]    #produce Need matrix    print '-------------------------------------'    print 'Need matrix:'    for i in range(p):        print 'process %d need resource '%i,Need[i],        if Finish[i]==True:            print 'Done !'        else:            print ''    print '-------------------------------------'    for i in range(p):        print '%d\t'%i,    print      for i in range(p):        print Finish[i],'\t',    print     print '-------------------------------------'if __name__=='__main__':    init();    initDS();    global n,p,Available,Max,Allocation,Need,Finish    while True:        print '-------------------------------------'        print         print         print         print '-------------------------------------'        c=raw_input('Query(q)/Allocate(a)/Exit(e)?\n>')        #c=lower(c)        print 'you input ',c        #print process        if c=='q':            query()        elif c=='a':            #Allocate            flag=1            print "There are %d process : (0~%d)"%(p,p-1)            tn=raw_input('Allocate resource for which process:  ')            #raw_input            tn=int(tn,10)            if tn>p or tn==p:                print 'no processs!'                continue            print 'there are %d resources:'%n            ta=[]            for i in range(n):                t=raw_input('Allocate Resource %s (need %d , access %d): '%(Available[i].name,Need[tn][i],Available[i].number))                t=int(t,10)                if t>Available[i].number:                    print 'we can\'t get so much resources,we use %d instead of %d'%(Available[i].number,t)                    t=Available[i].number                if t>Need[tn][i]:                    print 'you input too much resource and we use %d instead of %d'%(Need[tn][i],t)                    t=Need[tn][i]                ta.append(t)                del t            print 'You requests to allocate process',tn,'Resource',ta            print 'Checking!-----------'            for i in range(n):                Available[i].number-=ta[i]                Allocation[tn][i]+=ta[i]                Need[tn][i]-=ta[i]            print 'Safe Checking!---------------------'            if(safeCheck(tn,ta)):                print 'succeed allocate the resource'                tndone=1                for i in range(n):                    if Need[tn][i]>0:                        tndone=0                        break                if tndone==1:                    Finish[tn]=True                    #for i in range(n):print Available[i].number,                    #print                     for i in range(n):                        Available[i].number+=ta[i]                        Allocation[tn][i]=0                        Need[tn][i]=0                    #for i in range(n):print Available[i].number,                    #print                 alldone=1                for i in range(p):                    if Finish[i]==False:                        alldone=0                        break                if alldone==1:                    print '-------------------------------------'                    print 'Need matrix:'                    for i in range(p):                        print 'process %d need resource '%i,Need[i],                        if Finish[i]==True:                            print 'Done !'                        else:                            print ''                    print '-------------------------------------'                    print 'ALL DONE!'                    break            else:                print 'it\'s dangerous! we have cancel it'                #and release the error resoruces                for i in range(n):                    Available[i].number+=ta[i]                    Allocation[tn][i]-=ta[i]                    Need[tn][i]+=ta[i]            print '-------------------------------------'            for i in xrange(n):                print 'Available Resource %s,resource=%d'%(Available[i].name,Available[i].number)            print '-------------------------------------'            print 'Need matrix:'            for i in range(p):                print 'process %d need resource '%i,Need[i],                if Finish[i]==True:                    print 'Done !'                else:                    print ''            print '-------------------------------------'        elif c=='e':            break        else:            print '[-]Input Error !'        #print Resource    print 'All Done and Exit succeed!'

基本没有什么大问题。运行结果太长。就不贴上来了。。。