nmaier / nmaier.serialization

A (somewhat more) efficient binary formatter

A (somewhat more) efficient binary formatter

Because serialization is hard

Goals

• Be compatible enough with built-in C# Serialization, while still being efficient enough in the CPU, memory and storage size departments
  • Serialize most things incl. ISerializable
  • Omit feature I do not need, in particular, surrugates, events
• Provide an efficient (enough) binary representation that is still reliable (for persistence)
  • Use basic tags (ElementType) to mark in a stream what comes next
  • Provide specialized tags for things like null, PODs (including DateTime), enums, different arrays (empty, byte, 1-item, rank-1, PODs, generic objects), etc.
  • Allow cycles and copies by writing an object only once and writing references to that afterwards
  • Avoid duplicate strings
  • Tune writing of (unsigend) lengths (inspired by websocket frames)
    • < 254 will use one byte
    • <= ushort.MAXVALUE will use three bytes (16-bit + one byte for the tag (0xfe)
    • Otherwise use 5 bytes (32-bit + one byte for the tag (0xff))
    • Since most lengths written will be shortish, most will only use 1 byte instead of 4 bytes for an int.
  • Optimize assembly/type storage a bit (See also EfficientSerializationBinder.RegisterKnown)
• Thread-safe, reusable IFormatter (allowing to specify the StreamingContext per Serialize/Deserialize call)
  • Make use of Concurrent for global caches
• Be somewhat hackable (e.g. to add new optimized representations without breaking existing serialized representations)

Non-Goals

• Be entirely compatible
• Be secure (especially against tempering)
• Be error-resilient/use advanced error detection (against stream errors)
• Be memory efficient in the face of serializing tons of different object types (the caches are unlimited in growth by design)

State

Very alpha! You have been warned!

Good enough for caching stuff to disk (that is, you can regenerate things at any time)

Do not use this over the network unless you bolt message authentication on top. Or else an attacker will literally delete all your stuff!

Probably not a great idea to use this inter-application, either.

TODO

• Optimize list types
• Optimize dict types