Python生成文件的MD5和sha1

#coding=UTF-8
 
def fil_changefileext(filename,extname=''):
 # FIL ChangeFileExt 改变文件扩展名
 # filename 输入的文件路径名
 # extname='' 要更改分扩展名，如 .txt
 import os
 try:
 if extname[0]<>'.':
 extname='.'+extname
 except:
 extname=''
 if os.path.splitext(filename)[1]=='':
 uouttxt=filename+'.'+extname
 elif os.path.splitext(filename)[1]=='.':
 uouttxt=filename+extname 
 else:
 uouttxt=filename[:0-len(os.path.splitext(filename)[1])]+extname
 return uouttxt
 
def fil_str2file(fstr,filename):
 # FIL STR2File 把字符串保存到文件 
 try:
 outfile=open(filename,'w')
 outfile.writelines(fstr)
 outfile.close()
 return True 
 except:
 return False
 
#系统主程序开始
#-------------------------------------------------------
if __name__ == '__main__': 
 import os,sys,math
 # if len(sys.argv)==1:sys.argv.append(r'c:FreeNAS-8.0.4-RELEASE-x.iso')
 if len(sys.argv)>1:
 filepathname=sys.argv[1]
 if os.path.isfile(filepathname) :
 fmaxs = os.path.getsize(filepathname)+0.00
 fpos = 0.00
 ppos=0 
 pmax=50
 pjy=0 
 fmd5=fil_changefileext(filepathname,'.md5')
 fsha1=fil_changefileext(filepathname,'.sha')
 ffm=os.path.basename(filepathname) 
 #开始处理
 print 'Program Runing "'+filepathname+'" ...'
 import hashlib
 try:
 umd5str = hashlib.md5()
 usha1str = hashlib.sha1()
 xfilepathname=unicode(filepathname,'utf8')
 #需要使用二进制格式读取文件内容
 ufile = file(xfilepathname,'rb')
 while True:
 datas = ufile.read(1024*512)
 if not datas: break
 umd5str.update( datas )
 usha1str.update( datas )
 fpos=fpos+1024*512
 ppos=int(math.floor(fpos / fmaxs * 50))
 pposbfh=int(math.floor(fpos / fmaxs * 100))
 #打印进度条
 if pjy<>ppos: print '['+'*'*ppos +'='*(pmax-ppos)+'] '+str(pposbfh) +'%'
 #打印进度问题未解决，不知道print函数怎么退回到行首覆盖