遍历目录下的所有文件，计算文件的md5并输出

#encoding=utf-8
#author: skybug
#date: 2014-04-23
#function: 遍历目录所有文件，计算每个文件的md5 输出到md5.txt
import os,sys,getopt,hashlib
logfile='md5.txt'
limt=8388608  #(8M)
def listdir(dir):
    global  logfile
    logfile = dir + os.path.sep + logfile
    for files in os.listdir(dir) :
        path=os.path.join(dir,files)
        if os.path.isdir(path):
            continue
        else:
            filepath = dir + os.path.sep + files
            line = getfilemd5(filepath)
            w_log(logfile,line)
def getfilemd5(filepath):
    global limt
    size = os.path.getsize(filepath)
    f=open(filepath,'rb')
    if size < int(limt)+1:
        m1=hashlib.md5()
        m1.update(f.read(limt))
        myhash = m1.hexdigest().upper()
        line = filepath + ';' + myhash
        f.close()
        return line
        #print 'if' + '**'+ line
    else:
        m1=hashlib.md5()
        while True:
            block=f.read(limt)
            if not block:
                break
            m1.update(block)
        myhash = m1.hexdigest().upper()
        line = filepath + ';' + myhash
        f.close()
        return line
def w_log(log_file_name, line):
    try:
        log_file = open(log_file_name, 'a')
        line=line+'\n'
        log_file.write(line)
    except IOError as err:
        print('File error: ' + str(err))
    finally:
        if 'file' in locals():
            log_file.close()
dir = raw_input('please input dir:\n')
listdir(dir)