function parseUTF8()

in content/lib/paho-mqtt.js [640:686]
45 lines of code
10 McCabe index (conditional complexity)

	function parseUTF8(input, offset, length) {
		var output = "";
		var utf16;
		var pos = offset;

		while (pos < offset+length)
		{
			var byte1 = input[pos++];
			if (byte1 < 128)
				utf16 = byte1;
			else
			{
				var byte2 = input[pos++]-128;
				if (byte2 < 0)
					throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16),""]));
				if (byte1 < 0xE0)             // 2 byte character
					utf16 = 64*(byte1-0xC0) + byte2;
				else
				{
					var byte3 = input[pos++]-128;
					if (byte3 < 0)
						throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16)]));
					if (byte1 < 0xF0)        // 3 byte character
						utf16 = 4096*(byte1-0xE0) + 64*byte2 + byte3;
								else
								{
								   var byte4 = input[pos++]-128;
								   if (byte4 < 0)
						throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16), byte4.toString(16)]));
								   if (byte1 < 0xF8)        // 4 byte character
										   utf16 = 262144*(byte1-0xF0) + 4096*byte2 + 64*byte3 + byte4;
					   else                     // longer encodings are not supported
						throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16), byte4.toString(16)]));
								}
				}
			}

				if (utf16 > 0xFFFF)   // 4 byte character - express as a surrogate pair
				  {
					 utf16 -= 0x10000;
					 output += String.fromCharCode(0xD800 + (utf16 >> 10)); // lead character
					 utf16 = 0xDC00 + (utf16 & 0x3FF);  // trail character
				  }
			output += String.fromCharCode(utf16);
		}
		return output;
	}