Question

I’ve got an quite simple class that contains some primitive types and some collections with mostly enums. Now I need to serialize this object to the smallest possible size that is UTF8 compatible.

This is the class I need to serialize

public class Context
{
    public Hashtable UserModuleRoles { get; set; }
    public Dictionary<string, object> CustomSettings { get; set; }
    public int Uid { get; set; }
    public int Id { get; set; }
    public int ActiveId { get; set; }
    public byte Default { get; set; }
    public SetEnum Ident { get; set; }
    public string Name { get; set; }
    public sbyte State { get; set; }
    public DateTime Date { get; set; }
}

.

This is how I serialize the object

public string Serialize(object serializeObject)
{
    MemoryStream stream = new MemoryStream();
    BinaryFormatter b = new BinaryFormatter();

    b.Serialize(stream, serializeObject);

    byte[] data = stream.ToArray();

    stream.Dispose();
    stream = new MemoryStream();

    using (ZipFile zip = new ZipFile())
    {
        zip.AddEntry("data", data);
        zip.Save(stream);
    }

    data = stream.ToArray();
    stream.Dispose();

    return Convert.ToBase64String(data);
}

In my first attempt I serialize the object, zip that content (about 1/3 smaller) and convert it to a base64 string. But base64 has a quite big overhead of 1/3 and I know there is base128 but I don’t know how to start and my search for base128 encoding was unsuccessful.

• Or is there any other way to do this?

• And if not how is the best way to
  this as base128?

Edit:

I tested the ObjectStateFormatter Class with the whole “Context” object which results in 8byte more and slower serialization/deserialization. Maybe I had to use it just on the properties instead of the whole class?

Answer 1

Well, base128 is not that hard, if you know how base64 is done. The dutch wikipedia describes the process well (translated it for you):

1. Convert the data to binary.
2. Keep taking chunks of 7 bits (2^7 = 128)
3. Convert those 7 bits to an integer.
4. Look up that integer in a translation table that you defined and append the character found to the base128 string.

That translation table contains 128 compatible UTF8 characters, for example:

0: a
1: b
..
25: z
26: 0

The only requirement is that translation table is the same at both sender and reciever.