Pruned branches

Pruned branch cells are cells that represent deleted subtrees of the tree of cells.

May have any level between 1 and 3, which is equal to the level of a root of the pruned subtree plus one. Each of pruned branch cells get serialized as follows.

• The 1-byte tag that always equals 1.
• The byte that contains the pruned branch level mask, 1 <= mask <= 7. The number of hashes stored in the pruned branch cell is equal to the number of 1-bits in the mask.
• Next, h * 32 bytes store representations hashes of roots of the pruned subtrees starting from the last one. For example, if the mask equals 3 (binary 011), then the pruned tree cell contains representation hashes of the second and the first pruned subtrees in sequential order, but not the third one.
• Finally, h * 2 bytes store the depths of the pruned subtrees starting from the last one.