Class DeltaTree

java.lang.Object

io.crums.util.mrkl.Tree

io.crums.util.mrkl.DeltaTree

public class DeltaTree
extends Tree

A Merkle tree constructed from another with more leaves appended. The "delta" in the name refers not to deletions, but to the fact the data added and computed is incremental even when the base tree is arbitrarily large.

See Also:

• DeltaBuilder

Field Summary

Fields inherited from class io.crums.util.mrkl.Tree

BRANCH_PAD, LEAF_PAD

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DeltaTree(DeltaTree copy)	Copy constructor.
	DeltaTree(Tree base, byte[] deltaNodes)	Creates a new instance.

Method Summary

Modifier and Type	Method	Description
static int	computeNewLeafCount(Tree base, byte[] deltaNodes)	Infers and returns the number of leaves in the new tree given an array of deltas (additions) from a base tree.
byte[]	data(int level, int index)	Returns [a copy of] the data for the node at the specified coordinates.
int	leafWidth()	Returns the leaf width in bytes if fixed; -1, otherwise (variable).

Methods inherited from class io.crums.util.mrkl.Tree

appendToStringDetail, getHashAlgo, hash, hashAlgoWidth, hashInternals, hashInternals, hashLeaves, hashLeaves, hashUncommon, hashUncommon, idx, isLeafWidthFixed, isOmniWidth, proof, root, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

DeltaTree

public DeltaTree(Tree base,
 byte[] deltaNodes)

Creates a new instance.

Parameters:

base - the base tree

deltaNodes - new nodes of the tree. (Careful you don't create garbage.)

See Also:

• computeNewLeafCount(Tree, byte[])
• DeltaBuilder

DeltaTree

protected DeltaTree(DeltaTree copy)

Copy constructor.

Method Details

computeNewLeafCount

public static int computeNewLeafCount(Tree base,
 byte[] deltaNodes)
                               throws IllegalArgumentException

Infers and returns the number of leaves in the new tree given an array of deltas (additions) from a base tree.

Parameters:

base - an omni-width base tree (expected to be large)

deltaNodes - data array of length that is a multiple of Tree.hashAlgoWidth()

Returns:

the new number of leaves

Throws:

IllegalArgumentException

data

public byte[] data(int level,
 int index)

Description copied from class: Tree

Returns [a copy of] the data for the node at the specified coordinates. For internal nodes, this is just the node's hash, which is computed from the hash of its child nodes; for leaf nodes, the node's data may generally be anything, but more often than not it's the hash of a source object.

Specified by:

data in class Tree

See Also:

• Node.data()

leafWidth

public int leafWidth()

Description copied from class: Tree

Returns the leaf width in bytes if fixed; -1, otherwise (variable).

Specified by:

leafWidth in class Tree