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Use int64 in memory merkle tree
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@gdbelvin
gdbelvin committed Jan 25, 2017
1 parent a7e8e00 commit b84f1e9
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Showing 2 changed files with 54 additions and 39 deletions.
25 changes: 25 additions & 0 deletions merkle/common.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,25 @@
// Copyright 2016 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package merkle

// parent returns the index of the parent node in the parent level of the tree.
func parent(leafIndex int64) int64 {
return leafIndex >> 1
}

// isRightChild returns true if the node is a right child.
func isRightChild(leafIndex int64) bool {
return leafIndex&1 == 1
}
68 changes: 29 additions & 39 deletions merkle/memory_merkle_tree.go
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Original file line number Diff line number Diff line change
Expand Up @@ -59,8 +59,8 @@ func (t TreeEntry) HashInto(dest []byte) []byte {
// access to when testing the code and examining how it works
type TreeEntryDescriptor struct {
Value TreeEntry
XCoord int // The horizontal node coordinate
YCoord int // The vertical node coordinate
XCoord int64 // The horizontal node coordinate
YCoord int64 // The vertical node coordinate
}

// InMemoryMerkleTree holds a Merkle Tree in memory as a 2D node array
Expand Down Expand Up @@ -97,13 +97,13 @@ type InMemoryMerkleTree struct {
// at each level, all nodes computed so far, except possibly the last node,
// are fixed and will no longer change.
tree [][]TreeEntry
leavesProcessed int
levelCount int
leavesProcessed int64
levelCount int64
hasher TreeHasher
}

// isPowerOfTwoPlusOne tests whether a number is (2^x)-1 for some x. From MerkleTreeMath in C++
func isPowerOfTwoPlusOne(leafCount int) bool {
func isPowerOfTwoPlusOne(leafCount int64) bool {
if leafCount == 0 {
return false
}
Expand All @@ -116,18 +116,8 @@ func isPowerOfTwoPlusOne(leafCount int) bool {
return (((leafCount - 1) & (leafCount - 2)) == 0)
}

// parent returns the index of the parent node in the parent level of the tree.
func parent(leaf int) int {
return leaf >> 1
}

// isRightChild returns true if the node is a right child; false if it is the left (or only) child.
func isRightChild(leaf int) bool {
return (leaf & 1) != 0
}

// sibling returns the index of the node's (left or right) sibling in the same level.
func sibling(leaf int) int {
func sibling(leaf int64) int64 {
if isRightChild(leaf) {
return leaf - 1
}
Expand All @@ -145,7 +135,7 @@ func NewInMemoryMerkleTree(hasher TreeHasher) *InMemoryMerkleTree {
return &mt
}

func (mt *InMemoryMerkleTree) leafHash(leaf int) []byte {
func (mt *InMemoryMerkleTree) leafHash(leaf int64) []byte {
if leaf == 0 || leaf > mt.LeafCount() {
return nil
}
Expand All @@ -156,26 +146,26 @@ func (mt *InMemoryMerkleTree) leafHash(leaf int) []byte {
// NodeCount gets the current node count (of the lazily evaluated tree).
// Caller is responsible for keeping track of the lazy evaluation status. This will not
// update the tree.
func (mt *InMemoryMerkleTree) NodeCount(level int) int {
func (mt *InMemoryMerkleTree) NodeCount(level int64) int64 {
if mt.lazyLevelCount() <= level {
panic(fmt.Errorf("lazyLevelCount <= level in nodeCount: %d", mt.lazyLevelCount()))
}

return len(mt.tree[level])
return int64(len(mt.tree[level]))
}

// LevelCount returns the number of levels in the current Merkle tree
func (mt *InMemoryMerkleTree) LevelCount() int {
func (mt *InMemoryMerkleTree) LevelCount() int64 {
return mt.levelCount
}

// lazyLevelCount is the current level count of the lazily evaluated tree.
func (mt *InMemoryMerkleTree) lazyLevelCount() int {
return len(mt.tree)
func (mt *InMemoryMerkleTree) lazyLevelCount() int64 {
return int64(len(mt.tree))
}

// LeafCount returns the number of leaves in the tree.
func (mt *InMemoryMerkleTree) LeafCount() int {
func (mt *InMemoryMerkleTree) LeafCount() int64 {
if len(mt.tree) == 0 {
return 0
}
Expand All @@ -195,7 +185,7 @@ func (mt *InMemoryMerkleTree) root() TreeEntry {
}

// lastNode returns the last node of the given level in the tree.
func (mt *InMemoryMerkleTree) lastNode(level int) TreeEntry {
func (mt *InMemoryMerkleTree) lastNode(level int64) TreeEntry {
levelNodes := mt.NodeCount(level)

if levelNodes < 1 {
Expand All @@ -211,7 +201,7 @@ func (mt *InMemoryMerkleTree) addLevel() {
}

// pushBack appends a node to the level.
func (mt *InMemoryMerkleTree) pushBack(level int, treeEntry TreeEntry) {
func (mt *InMemoryMerkleTree) pushBack(level int64, treeEntry TreeEntry) {
if mt.lazyLevelCount() <= level {
panic(fmt.Errorf("lazyLevelCount <= level in pushBack: %d", mt.lazyLevelCount()))
}
Expand All @@ -220,7 +210,7 @@ func (mt *InMemoryMerkleTree) pushBack(level int, treeEntry TreeEntry) {
}

// popBack pops (removes and returns) the last node of the level.
func (mt *InMemoryMerkleTree) popBack(level int) {
func (mt *InMemoryMerkleTree) popBack(level int64) {
if len(mt.tree[level]) < 1 {
panic(errors.New("no nodes to pop in popBack"))
}
Expand All @@ -235,11 +225,11 @@ func (mt *InMemoryMerkleTree) popBack(level int) {
//
// Returns the position of the leaf in the tree. Indexing starts at 1,
// so position = number of leaves in the tree after this update.
func (mt *InMemoryMerkleTree) AddLeaf(leafData []byte) (int, TreeEntry) {
func (mt *InMemoryMerkleTree) AddLeaf(leafData []byte) (int64, TreeEntry) {
return mt.addLeafHash(mt.hasher.HashLeaf(leafData))
}

func (mt *InMemoryMerkleTree) addLeafHash(leafData []byte) (int, TreeEntry) {
func (mt *InMemoryMerkleTree) addLeafHash(leafData []byte) (int64, TreeEntry) {
treeEntry := TreeEntry{}
treeEntry.hash = leafData

Expand Down Expand Up @@ -277,7 +267,7 @@ func (mt *InMemoryMerkleTree) CurrentRoot() TreeEntry {
//
// Returns an empty string if the snapshot requested is in the future
// (i.e., the tree is not large enough).
func (mt *InMemoryMerkleTree) RootAtSnapshot(snapshot int) TreeEntry {
func (mt *InMemoryMerkleTree) RootAtSnapshot(snapshot int64) TreeEntry {
if snapshot == 0 {
return TreeEntry{mt.hasher.HashEmpty()}
}
Expand All @@ -296,7 +286,7 @@ func (mt *InMemoryMerkleTree) RootAtSnapshot(snapshot int) TreeEntry {
}

// updateToSnapshot updates the tree to a given snapshot (if necessary), returns the root.
func (mt *InMemoryMerkleTree) updateToSnapshot(snapshot int) TreeEntry {
func (mt *InMemoryMerkleTree) updateToSnapshot(snapshot int64) TreeEntry {
if snapshot == 0 {
return TreeEntry{mt.hasher.HashEmpty()}
}
Expand All @@ -318,7 +308,7 @@ func (mt *InMemoryMerkleTree) updateToSnapshot(snapshot int) TreeEntry {
}

// Update tree, moving up level-by-level.
level := 0
level := int64(0)
// Index of the first node to be processed at the current level.
firstNode := mt.leavesProcessed
// Index of the last node.
Expand Down Expand Up @@ -359,8 +349,8 @@ func (mt *InMemoryMerkleTree) updateToSnapshot(snapshot int) TreeEntry {

// recomputePastSnapshot returns the root of the tree as it was for a past snapshot.
// If node is not nil, additionally records the rightmost node for the given snapshot and node_level.
func (mt *InMemoryMerkleTree) recomputePastSnapshot(snapshot int, nodeLevel int, node *TreeEntry) TreeEntry {
level := 0
func (mt *InMemoryMerkleTree) recomputePastSnapshot(snapshot int64, nodeLevel int64, node *TreeEntry) TreeEntry {
level := int64(0)
// Index of the rightmost node at the current level for this snapshot.
lastNode := snapshot - 1

Expand Down Expand Up @@ -426,7 +416,7 @@ func (mt *InMemoryMerkleTree) recomputePastSnapshot(snapshot int, nodeLevel int,
// is one below the root.
// Returns an empty slice if the tree is not large enough
// or the leaf index is 0.
func (mt *InMemoryMerkleTree) PathToCurrentRoot(leaf int) []TreeEntryDescriptor {
func (mt *InMemoryMerkleTree) PathToCurrentRoot(leaf int64) []TreeEntryDescriptor {
return mt.PathToRootAtSnapshot(leaf, mt.LeafCount())
}

Expand All @@ -437,7 +427,7 @@ func (mt *InMemoryMerkleTree) PathToCurrentRoot(leaf int) []TreeEntryDescriptor
// last element is one below the root. Returns an empty slice if
// the leaf index is 0, the snapshot requested is in the future or
// the snapshot tree is not large enough.
func (mt *InMemoryMerkleTree) PathToRootAtSnapshot(leaf int, snapshot int) []TreeEntryDescriptor {
func (mt *InMemoryMerkleTree) PathToRootAtSnapshot(leaf int64, snapshot int64) []TreeEntryDescriptor {
if leaf > snapshot || snapshot > mt.LeafCount() || leaf == 0 {
return []TreeEntryDescriptor{}
}
Expand All @@ -447,15 +437,15 @@ func (mt *InMemoryMerkleTree) PathToRootAtSnapshot(leaf int, snapshot int) []Tre

// pathFromNodeToRootAtSnapshot returns the path from a node at a given level
// (both indexed starting with 0) to the root at a given snapshot.
func (mt *InMemoryMerkleTree) pathFromNodeToRootAtSnapshot(node int, level int, snapshot int) []TreeEntryDescriptor {
func (mt *InMemoryMerkleTree) pathFromNodeToRootAtSnapshot(node int64, level int64, snapshot int64) []TreeEntryDescriptor {
var path []TreeEntryDescriptor

if snapshot == 0 {
return path
}

// Index of the last node.
lastNode := (snapshot - 1) >> uint(level)
lastNode := (snapshot - 1) >> uint64(level)

if level >= mt.levelCount || node > lastNode || snapshot > mt.LeafCount() {
return path
Expand Down Expand Up @@ -496,14 +486,14 @@ func (mt *InMemoryMerkleTree) pathFromNodeToRootAtSnapshot(node int, level int,
// Returns a slice of node hashes, ordered according to levels.
// Returns an empty slice if snapshot1 is 0, snapshot 1 >= snapshot2,
// or one of the snapshots requested is in the future.
func (mt *InMemoryMerkleTree) SnapshotConsistency(snapshot1 int, snapshot2 int) []TreeEntryDescriptor {
func (mt *InMemoryMerkleTree) SnapshotConsistency(snapshot1 int64, snapshot2 int64) []TreeEntryDescriptor {
var proof []TreeEntryDescriptor

if snapshot1 == 0 || snapshot1 >= snapshot2 || snapshot2 > mt.LeafCount() {
return proof
}

level := 0
level := int64(0)
// Rightmost node in snapshot1.
node := snapshot1 - 1

Expand Down

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