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Reference Encoding

There are Ref, Refs and Dynamic references. Where

• Ref points to single obejct
• Refs is like slice of objects
• Dynamic is like interface{}, e.g. schema of the reference described by the reference, not tag

Basis of every reference is SHA256 hash of encoded value.

Ref

The Ref is structure that contains SHA256 hash. Encoded value represents the hash only, and can be decoded to the hash, or encoded from the hash.

Refs

The Refs represented as Merkle-tree with some degree. E.g. every node of the tree contains 'degree' child nodes. By default the degree is 16 and can be configured. The Refs itself is SHA256 hash that points to some encoded value (see image below). If the hash is blank (zero bytes only), then the Refs represents empty slice.

If the Depth is 0, then the encoded Refs point directly to elements, otherwise it points to encoded Refs nodes. The Length is amount of non-zero elements in subtree. Thus, a node can contains empty (zero) elements that doesn't count. This way, we can delete an element without tree reconstructing. If tree is full, and we need to insert another element, then we need to increase the depth of the tree (actually, depth is height of the tree). The Depth is depth - 1. Max number of elements that tree can contain is power(Degree, Depth+1). If many elements removed, then we can reduce the depth, removing empty (zero) elements

So, encoding:

• Refs - SHA256 hash
• encoded Refs

  Depth  uint32
  Degree uint32
  Length uint32
  Nested []cipher.SHA256
  

• encoded Refs node

  Length uint32
  Nested []cipher.SHA256
  

Dynamic

A Dynamic contains reference to object and reference to schema of the object. Schema is first. Both are SHA256 hash.

Schema SHA256
Object SHA256