/**
 *
 *  Base64 encode / decode
 *  http://www.webtoolkit.info/
 *
 **/
define([], function () {
  var Base64 = {

    // private property
    _keyStr: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",

    // public method for encoding
    encode: function (input) {
      var output = "";
      var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
      var i = 0;
      input = Base64._utf8_encode(input);
      while (i < input.length) {
        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 +
          this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
          this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);

      }

      return output;
    },

    // public method for decoding
    decode: function (input) {
      var output = "";
      var chr1, chr2, chr3;
      var enc1, enc2, enc3, enc4;
      var i = 0;

      input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

      while (i < input.length) {

        enc1 = this._keyStr.indexOf(input.charAt(i++));
        enc2 = this._keyStr.indexOf(input.charAt(i++));
        enc3 = this._keyStr.indexOf(input.charAt(i++));
        enc4 = this._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);
        }

      }
      output = Base64._utf8_decode(output);
      return output;
    },

    // private method for UTF-8 encoding
    _utf8_encode: function (string) {
      string = string.replace(/\r\n/g, "\n");
      var utftext = "";

      for (var n = 0; n < string.length; n++) {

        var c = string.charCodeAt(n);

        if (c < 128) {
          utftext += String.fromCharCode(c);
        } else if ((c > 127) && (c < 2048)) {
          utftext += String.fromCharCode((c >> 6) | 192);
          utftext += String.fromCharCode((c & 63) | 128);
        } else {
          utftext += String.fromCharCode((c >> 12) | 224);
          utftext += String.fromCharCode(((c >> 6) & 63) | 128);
          utftext += String.fromCharCode((c & 63) | 128);
        }

      }

      return utftext;
    },

    // private method for UTF-8 decoding
    _utf8_decode: function (utftext) {
      var string = "";
      var i = 0;
      var c = c1 = c2 = 0;

      while (i < utftext.length) {

        c = utftext.charCodeAt(i);

        if (c < 128) {
          string += String.fromCharCode(c);
          i++;
        } else if ((c > 191) && (c < 224)) {
          c2 = utftext.charCodeAt(i + 1);
          string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
          i += 2;
        } else {
          c2 = utftext.charCodeAt(i + 1);
          c3 = utftext.charCodeAt(i + 2);
          string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
          i += 3;
        }

      }

      return string;
    }

  }
  return Base64;
});
