binbase64[GhostFromHeaven]

# -*- coding: utf-8 -*- #@File name : binbase64.py #@Auther : GhostFromHeaven[csdn] #@date : 2012-07-19 from filehelper import * #For more information about Base64 please read: http://zh.wikipedia.org/wiki/Base64 _CODE_CHAR = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" def binbase64(data): """ Convert binary data to Base64 format string. """ base64str = "" for i in range(len(data)/3): datavalue = ((data[3*i] << 16) | (data[3*i+1] << 8) | data[3*i+2]) for j in range(4): base64str += _CODE_CHAR[(datavalue >> 6*(3-j)) & 0x3F] dataremain = len(data) % 3 if dataremain == 1: datavalue = data[-1] << 16; base64str += _CODE_CHAR[(datavalue >> 18) & 0x3F] base64str += _CODE_CHAR[(datavalue >> 12) & 0x3F] base64str += "==" elif dataremain == 2: datavalue = (data[-2] << 16) | (data[-1] << 8); base64str += _CODE_CHAR[(datavalue >> 18) & 0x3F] base64str += _CODE_CHAR[(datavalue >> 12) & 0x3F] base64str += _CODE_CHAR[(datavalue >> 6) & 0x3F] base64str += "=" return base64str def strbase64(astr): """ Convert a string to Base64 format string. """ return binbase64(map(ord, astr)) class Base64Error(Exception): """ Exception for Base64 error. """ pass def base64bin(encodedstr): """ Convert Base64 format string to binary data. """ if len(encodedstr) % 4: raise Base64Error("The length of input 'base64str' MUST be multiple of 4.") rawbase64str = encodedstr.rstrip("=") if (len(rawbase64str) % 4) == 1: raise Base64Error("Too many '=' characters, MUST NOT be more than 2.") for x in rawbase64str: if x not in _CODE_CHAR: raise Base64Error("Unexpected character %s.", x) data=[] for i in range(len(rawbase64str)/4): datavalue = (_CODE_CHAR.find(rawbase64str[4*i]) << 18) \ | (_CODE_CHAR.find(rawbase64str[4*i+1]) << 12) \ | (_CODE_CHAR.find(rawbase64str[4*i+2]) << 6) \ | (_CODE_CHAR.find(rawbase64str[4*i+3])) data.append((datavalue >> 16) & 0xFF) data.append((datavalue >> 8) & 0xFF) data.append((datavalue) & 0xFF) strremain = len(rawbase64str) % 4 if strremain == 2: datavalue = (_CODE_CHAR.find(rawbase64str[-2]) << 18) \ | (_CODE_CHAR.find(rawbase64str[-1]) << 12) data.append((datavalue >> 16) & 0xFF) elif strremain == 3: datavalue = (_CODE_CHAR.find(rawbase64str[-3]) << 18) \ | (_CODE_CHAR.find(rawbase64str[-2]) << 12) \ | (_CODE_CHAR.find(rawbase64str[-1]) << 6) data.append((datavalue >> 16) & 0xFF) data.append((datavalue >> 8) & 0xFF) return data def base64str(encodedstr): """ Convert Base64 format string to a string. """ return "".join(map(chr,base64bin(encodedstr))) def binfiletobase64(inp, out): """ Convert binary file to Base64 format text file. """ blocksize = 76 / 4 * 3 def _binfiletobase64(fin, fout): while True: chunk = fin.read(blocksize) if chunk: fout.write(strbase64(chunk)) fout.write("\n") else: break fileinoutpattern(inp, out, _binfiletobase64, inmode="rb", outmode="w") def base64filetobin(inp, out): """ Convert Base64 format text file to binary file. """ def _base64filetobin(fin, fout): for line in fin: fout.write(base64str(line.rstrip())) fileinoutpattern(inp, out, _base64filetobin, inmode="r", outmode="wb") def test(): """ Self testing. """ rawstr = "Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, that by a perseverance of delight in the continued and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure." encodedstr = binbase64(map(ord, rawstr)) for x in range(0, len(encodedstr), 76): print encodedstr[x:x+76] encodedstr = strbase64(rawstr) for x in range(0, len(encodedstr), 76): print encodedstr[x:x+76] data = base64bin(encodedstr) decodedstr = "".join(map(chr,data)) print decodedstr assert decodedstr == rawstr decodedstr = base64str(encodedstr) print decodedstr assert decodedstr == rawstr #base64str(encodedstr[:-1]);#Not multiple of 4 #base64str(encodedstr[:-3]+"==");#Too many '=' #base64str(encodedstr[:-2]+"()");#Invaild characters '(' and ')' binfiletobase64(r"D:\2.zip", r"D:\2.txt") base64filetobin(r"D:\2.txt", r"D:\2.1.zip") print "OK" if __name__ == "__main__": test()