function decode(str) {
	  var decoded = 0;
	
	  for (i = 0; i < str.length; i++) {
	    decoded = decoded * length + map[str.charAt(i)];
	  }
	
	  return decoded;
	}
Return the integer value specified by the given string.

@param {String} str The string to convert.
@returns {Number} The integer value represented by the string.
@api public