/*
 * Title  -> JavaScript Base64 Encoder Decoder
 * Author -> Paul Gration
 * URL    -> http://www.i-labs.org
 * Email  -> pmgration(at)i-labs.org
 */

function JavaScriptBase64()
{
    var string;
    var base64;

    this.JavaScriptBase64 = function(string)
    {
        this.string = new String(string);
        this.base64 = 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','*','/');
    }
    
    this.encode = function()
    {
        var binary = new String();
        var result = new String();
        for(i = 0; i < this.string.length; i++)
        {
            binary += String("00000000" + this.string.charCodeAt(i).toString(2)).substring(this.string.charCodeAt(i).toString(2).length);
        }
        for(i = 0; i < binary.length; i+=6)
        {
            var number = new Number();
            var counter = new Number();
            for(j = 0; j < binary.substring(i, i+6).length; j++)
            {
                for(k = 32; k >= 1; k-=(k/2))
                {
                    if(binary.substring(i, i+6).charAt(counter++) == "1")
                    {
                        number += k;
                    }
                }
            }
            result += this.base64[number];
        }
        return result;
    }

    this.decode = function()
    {
        var binary = new String();
        var result = new String();
        for(i = 0; i < this.string.length; i++)
        {
            for(j = 0; j < this.base64.length; j++)
            {
                if(this.string.charAt(i) == this.base64[j])
                {
                    binary += String("000000" + j.toString(2)).substring(j.toString(2).length);
                }
            }
        }
        for(i = 0; i < binary.length; i+=8)
        {
            var number = new Number();
            var counter = new Number();
            for(j = 0; j < binary.substring(i, i+8).length; j++)
            {
                for(k = 128; k >= 1; k-=(k/2))
                {
                    if(binary.substring(i, i+8).charAt(counter++) == "1")
                    {
                        number += k;
                    }
                }
            }
            result += String.fromCharCode(number);
        }
        return result;
    }
}

var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

function encode64(input) {
   var output = "";
   var chr1, chr2, chr3;
   var enc1, enc2, enc3, enc4;
   var i = 0;

   do {
      chr1 = input.charCodeAt(i++);
      chr2 = input.charCodeAt(i++);
      chr3 = input.charCodeAt(i++);

      enc1 = chr1 >> 2;
      enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
      enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
      enc4 = chr3 & 63;

      if (isNaN(chr2)) {
         enc3 = enc4 = 64;
      } else if (isNaN(chr3)) {
         enc4 = 64;
      }

      output = output + keyStr.charAt(enc1) + keyStr.charAt(enc2) + 
         keyStr.charAt(enc3) + keyStr.charAt(enc4);
   } while (i < input.length);
   
   return output;
}

function decode64(input) {
   var output = "";
   var chr1, chr2, chr3;
   var enc1, enc2, enc3, enc4;
   var i = 0;

   // remove all characters that are not A-Z, a-z, 0-9, +, /, or =
   input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

   do {
      enc1 = keyStr.indexOf(input.charAt(i++));
      enc2 = keyStr.indexOf(input.charAt(i++));
      enc3 = keyStr.indexOf(input.charAt(i++));
      enc4 = keyStr.indexOf(input.charAt(i++));

      chr1 = (enc1 << 2) | (enc2 >> 4);
      chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
      chr3 = ((enc3 & 3) << 6) | enc4;

      output = output + String.fromCharCode(chr1);

      if (enc3 != 64) {
         output = output + String.fromCharCode(chr2);
      }
      if (enc4 != 64) {
         output = output + String.fromCharCode(chr3);
      }
   } while (i < input.length);

   return output;
}