// Base64 encoder/decoder - pulled from http://ostermiller.org/calc/encode.html. Licensed under the GPL.

var END_OF_INPUT = -1;

var base64Chars = new Array(

    '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','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','6','7','8','9','+','/'

);

var reverseBase64Chars = new Array();

for (var i=0; i < base64Chars.length; i++){

    reverseBase64Chars[base64Chars[i]] = i;

}

var base64Str;

var base64Count;

function setBase64Str(str){

    base64Str = str;

    base64Count = 0;

}

function readBase64(){    

    if (!base64Str) return END_OF_INPUT;

    if (base64Count >= base64Str.length) return END_OF_INPUT;

    var c = base64Str.charCodeAt(base64Count) & 0xff;

    base64Count++;

    return c;

}

function encodeBase64(str){

    setBase64Str(str);

    var result = '';

    var inBuffer = new Array(3);

    var lineCount = 0;

    var done = false;

    while (!done && (inBuffer[0] = readBase64()) != END_OF_INPUT){

        inBuffer[1] = readBase64();

        inBuffer[2] = readBase64();

        result += (base64Chars[ inBuffer[0] >> 2 ]);

        if (inBuffer[1] != END_OF_INPUT){

            result += (base64Chars [(( inBuffer[0] << 4 ) & 0x30) | (inBuffer[1] >> 4) ]);

            if (inBuffer[2] != END_OF_INPUT){

                result += (base64Chars [((inBuffer[1] << 2) & 0x3c) | (inBuffer[2] >> 6) ]);

                result += (base64Chars [inBuffer[2] & 0x3F]);

            } else {

                result += (base64Chars [((inBuffer[1] << 2) & 0x3c)]);

                result += ('=');

                done = true;

            }

        } else {

            result += (base64Chars [(( inBuffer[0] << 4 ) & 0x30)]);

            result += ('=');

            result += ('=');

            done = true;

        }

        lineCount += 4;

        if (lineCount >= 76){

            result += ('\n');

            lineCount = 0;

        }

    }

    return result;

}

function readReverseBase64(){   

    if (!base64Str) return END_OF_INPUT;

    while (true){      

        if (base64Count >= base64Str.length) return END_OF_INPUT;

        var nextCharacter = base64Str.charAt(base64Count);

        base64Count++;

        if (reverseBase64Chars[nextCharacter]){

            return reverseBase64Chars[nextCharacter];

        }

        if (nextCharacter == 'A') return 0;

    }

    return END_OF_INPUT;

}

function ntos(n){

    n=n.toString(16);

    if (n.length == 1) n="0"+n;

    n="%"+n;

    return unescape(n);

}

function decodeBase64(str){

    setBase64Str(str);

    var result = "";

    var inBuffer = new Array(4);

    var done = false;

    while (!done && (inBuffer[0] = readReverseBase64()) != END_OF_INPUT

        && (inBuffer[1] = readReverseBase64()) != END_OF_INPUT){

        inBuffer[2] = readReverseBase64();

        inBuffer[3] = readReverseBase64();

        result += ntos((((inBuffer[0] << 2) & 0xff)| inBuffer[1] >> 4));

        if (inBuffer[2] != END_OF_INPUT){

            result +=  ntos((((inBuffer[1] << 4) & 0xff)| inBuffer[2] >> 2));

            if (inBuffer[3] != END_OF_INPUT){

                result +=  ntos((((inBuffer[2] << 6)  & 0xff) | inBuffer[3]));

            } else {

                done = true;

            }

        } else {

            done = true;

        }

    }

    return result;

}