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js/base64.js 3.63 KB
a0daba42   Jean Wasilewski   Partial base64 an...
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  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;
      }
   
  }