README.md

BigObjectSerializer

This library attempts to provide a serializer that can handle very large objects efficiently. This includes objects that take up well over 1GB+ in memory. As of now the NewtonSoft JSON.NET serializer typically performs at the same serialization speed while having a file size of roughly double compared to BigObjectSerializer. This is still an early work in progress, with the end goal of exceeding NewtonSoft's serialization speed.

Comparisons

NewtonSoft's JSON.NET serialization is used as the benchmark because it is the fastest available reflection-based serializer. Other serializers were examined, including Protobuf (which does not support very large objects and does not have a reflection-based serializer), Flatbuffers (which requires the entire serialized object to be in memory prior to writing to the stream, and for C# has a 2GB limit), MessagePack (which has a significantly slower reflection-based serializer than NewtonSoft), and BinaryFormatter (which is also significantly slower than NewtonSoft's reflection-based serializer).

Implementation

BigObjectSerializer is implemented as a queue (FIFO). This allows us to make assumptions about how the values are stored.

Examples

Reflection based

Serialization:

using (var stream = File.Open("test.bin", FileMode.Create))
using (var serializer = new BigObjectSerializer(stream))
{
    serializer.PushObject(myObject);
    serializer.Flush();
}

Deserialization:

using (var stream = File.Open("test.bin", FileMode.Open))
using (var deserializer = new BigObjectDeserializer(stream))
{
    var myObject = deserializer.PopObject<MyClass>();
}

Manual

Serialization:

using (var stream = File.Open("test.bin", FileMode.Create))
using (var serializer = new BigObjectSerializer(stream))
{
    serializer.PushInt(1234);
    serializer.PushString("Test String");
    serializer.PushGuid(Guid.NewGuid());
    serializer.PushDouble(123.456);
    serializer.PushObject(new List<string>() { "one", "two", "three" });

    serializer.Flush();
}

Deserialization:

using (var stream = File.Open("test.bin", FileMode.Open))
using (var deserializer = new BigObjectDeserializer(stream))
{
    var myInt = deserializer.PopInt();
    var myString = deserializer.PopString();
    var myGuid = deserializer.PopGuid();
    var myDouble = deserializer.PopDouble();
    var myList = deserializer.PopObject<IList<string>>();
}

Supported types

The following are types supported in addition to the reflection-based object serializer, which supports serialization of a class instance's properties that have getter/setters.

• int
• uint
• short
• long
• ulong
• byte
• bool
• float
• double
• string
• Guid

Additionally, the serializer supports types that implement the following interfaces. For now, these types must be used when deserializing (so use PopObject<IList< string >>() instead of PopObject<List< string >>()). The same goes for any nested properties within a class object to be serialized.

• ISet<>
• IDictionary<,>
• IList<>
• IEnumerable<>

In the future more types will be added. Additionally, all types can be pushed and popped using the "PushObject/PopObject", it's just better performance to directly call PushInt/PopInt for example.

TODO

• Unit tests. I am sure there are many bugs and edge cases to cover (I believe one is Dictionaries with null value entries) that need to be tested.
• As of now only 255 properties per class object are supported. Probably should update from using a byte to a ushort to increase this to a 65k property limit with minimal performance impact.
• Add proper benchmarking results.