sixBitEncode

Anybody could convert the encode function to Python?

It comes from mPlayer - Flash MP3 Player with URL encryption

Code:

// sixBitEncode
// released 10.10.03 10a
// by zeh @ PROTOTYPE (http://proto.layer51.com/)
// License: Copyleft (http://www.gnu.org/copyleft/copyleft.html)


String.prototype.sixBitEncode = function () {
var ntexto = "";
var nntexto = "";
var codeKey = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-"
var charCode, charCodeBin, charChar;
for (i=0; i< this.length; i++) {
charCode = this.charCodeAt(i) & 255; // char code
charCodeBin = ("00000000" + charCode.toString(2)).substr(-8,8); // char code in binary
ntexto += charCodeBin;
}
for (i=0; i< ntexto.length; i+=6) {
charCodeBin = ntexto.substr(i, 6); // char code in binary, 6 bits
if (charCodeBin.length < 6) charCodeBin = (charCodeBin+"000000").substr(0,6);
charCode = parseInt(charCodeBin, 2);
nntexto += codeKey.substr(charCode, 1);
}
return (nntexto);
}

String.prototype.sixBitDecode = function () {
var ntexto = "";
var nntexto = "";
var codeKey = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-"
var charCode, charCodeBin;
for (i=0; i<this.length; i++) {
charCode = codeKey.indexOf(this.substr(i,1)); // char index
charCodeBin = ("000000" + charCode.toString(2)).substr(-6,6); // char index in binary, 6 bits
ntexto += charCodeBin;
}
for (i=0; i< ntexto.length; i+=8) {
charCodeBin = ntexto.substr(i, 8); // char code in binary
charCode = parseInt(charCodeBin, 2);
charChar = String.fromCharCode(charCode);
nntexto += charChar;
}
return (nntexto);
}

Decode function (while not very elegant, but working) is available from here

Code:

def int2bin(n):
    assert n >= 0, "Number must be positive"
    res = ""
    if n == 0: return "0"
    while True:
        if n == 0:
            return res
        elif n % 2 == 0:
            res = "0" + res
        else:
            res = "1" + res
            n -= 1
        n /= 2

def decode(source):
    key = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-"
    binary = ""

    for char in source:
        code = key.find(char) # look up each char in the code key
        binary += int2bin(code).rjust(6, "0") # append char index as a six bit binary string
    
    chunks = [] 
    # split string into segments of length 8
    while len(binary) > 0:
        chunks.append(binary[:8]) 
        binary = binary[8:]

    chars = [chr(int(x, 2)) for x in chunks] # convert the segments to chars
    return "".join(chars)

# http://www.mabd.se/?p=682
test = "aHR0cDovL3N0cmVhbTAuZWFyLmR1b21pLmNvbS9SeWx5bm4ubXAzA"
print(test, decode(test))

The player is used in various places ie ILoveMusic

Original Actionscript is here

Thanks

sebus