short url的一个python实现

import hashlib
def shorturl(url):
        base32 = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
    'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p',
    'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
    'y', 'z', '0', '1', '2', '3', '4', '5']

        m = hashlib.md5()
        m.update(url)
        hexStr = m.hexdigest()
        hexStrLen = len(hexStr)
        subHexLen = hexStrLen / 8


        output = []
        for i in range(0,subHexLen):
                subHex = '0x'+hexStr[i*8:(i+1)*8]
                res = 0x3FFFFFFF & int(subHex,16)

                out = ''
                for j in range(6):
                        val = 0x0000001F & res
                        out += (base32[val])
                        res = res >> 5
                output.append(out)
        return output