base64编码-Python

# base64解码 class Decoder(object): tables = None def __init__(self): self.__generateCodeTable() def __generateCodeTable(self): """ 解码的码表 """ codeTable = {} # ord(ss) 输出字符的ascii # chr(num) 输出数值对应的字符 init_char = ord('A') - 1 for i in range(26): init_char = chr(init_char + 1) codeTable[init_char] = i init_char = ord('a') - 1 for j in range(26,52): init_char = chr(init_char + 1) codeTable[init_char] = j init_char = ord('0') -1 for k in range(52,62): init_char = chr(init_char + 1) codeTable[init_char] = k codeTable['+'] = 62 codeTable['/'] = 63 self.tables = codeTable def __characterTo6Bin(self,msg): """ 将每个字符串转化为6位的二进制 """ result = '' for i in range(len(msg)): tep_str = '' tmp = bin(self.tables.get(msg[i]))[2:] if len(tmp) < 6 : num = 6 - len(tmp) for j in range(num): tep_str += '0' tep_str += tmp result += tep_str return result def decode(self,msg): """ 解码base64编码的字符 """ index = msg.find('=') if index != -1: msg = msg[0:index] result = [] str_bin = self.__characterTo6Bin(msg) length = len(str_bin) index = 0 while index < length: if int(str_bin[index:index+8],2) > 127: tmp = str_bin[index:index+24] hex_str = str(hex(int(tmp,2))) hex_str = hex_str.replace('0x','') result.append(str(bytes.fromhex(hex_str),encoding='utf-8')) index += 24 else: sub = str_bin[index:index+8] result.append(chr(int(sub,2))) index += 8 if result[-1] == 0: result = result[0:-1] origin = "" for key in result: origin += key return origin.replace('\x00','') decode = Decoder() decode.decode('5Lit5Zu9')