Json.NET crashes when serializing unsigned integer (ulong) array

Question

Getting a parser error when trying to serialize a ulong array, looks like the Json.NET library isnt checking if the integer is signed or unsigned; any one know of a workaround for this? or any other .NET Json library that can handle unsigned int's?

*EDIT: code below; * It serializes fine, but when its deserializing it throws an error; Looks like it doesnt cater for the unsigned int from looking at the stack trace;

NewTonsoft.Json.JsonReaderException : {"JSON integer 18446744073709551615 is too large or small for an Int64."}

Value was either too large or too small for an Int64.
   at System.Number.ParseInt64(String value, NumberStyles options, NumberFormatInfo numfmt)
   at System.Convert.ToInt64(String value, IFormatProvider provider)
   at Newtonsoft.Json.JsonTextReader.ParseNumber() in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\JsonTextReader.cs:line 1360

   class Program
        {
            static void Main(string[] args)
            {
                string output = JsonConvert.SerializeObject(new ulong[] {ulong.MinValue, 20, 21, 22, ulong.MaxValue});
                Console.WriteLine(output);

                ulong[] array = JsonConvert.DeserializeObject<ulong[]>(output);
                Console.WriteLine(array);

                Console.ReadLine();
            }
        }

Answer 1

ECMA-262, the standard on which JSON is based, specifies in section 4.3.19 that number values are IEEE double-precision floating point values, commonly seen as the "double" type in C-like languages. This encoding is not sufficiently precise to represent all possible values of 64 bit integers.

Therefore, encoding 64 bit integers (signed or otherwise) in JSON may lead to a loss in precision if it passes through any code which processes it in keeping with the standard. As seen in JSON.net, it might also break code which does not correctly implement the standard, but rather assumes that people won't try to do failure-prone things.