mirror of
https://github.com/nspcc-dev/neo-go.git
synced 2024-11-23 13:38:35 +00:00
ddad9ac9a3
buildMerkleTree() is internal to the hash package and if anyone calls it with `len(leaves) == 0` he deserves a panic. As it's the only error case in it, we can remove error value return from this function and simplify NewMerkleTree().
85 lines
1.9 KiB
Go
85 lines
1.9 KiB
Go
package hash
|
|
|
|
import (
|
|
"errors"
|
|
|
|
"github.com/CityOfZion/neo-go/pkg/util"
|
|
)
|
|
|
|
// MerkleTree implementation.
|
|
type MerkleTree struct {
|
|
root *MerkleTreeNode
|
|
depth int
|
|
}
|
|
|
|
// NewMerkleTree returns new MerkleTree object.
|
|
func NewMerkleTree(hashes []util.Uint256) (*MerkleTree, error) {
|
|
if len(hashes) == 0 {
|
|
return nil, errors.New("length of the hashes cannot be zero")
|
|
}
|
|
|
|
nodes := make([]*MerkleTreeNode, len(hashes))
|
|
for i := 0; i < len(hashes); i++ {
|
|
nodes[i] = &MerkleTreeNode{
|
|
hash: hashes[i],
|
|
}
|
|
}
|
|
|
|
return &MerkleTree{
|
|
root: buildMerkleTree(nodes),
|
|
depth: 1,
|
|
}, nil
|
|
}
|
|
|
|
// Root returns the computed root hash of the MerkleTree.
|
|
func (t *MerkleTree) Root() util.Uint256 {
|
|
return t.root.hash
|
|
}
|
|
|
|
func buildMerkleTree(leaves []*MerkleTreeNode) *MerkleTreeNode {
|
|
if len(leaves) == 0 {
|
|
panic("length of leaves cannot be zero")
|
|
}
|
|
if len(leaves) == 1 {
|
|
return leaves[0]
|
|
}
|
|
|
|
parents := make([]*MerkleTreeNode, (len(leaves)+1)/2)
|
|
for i := 0; i < len(parents); i++ {
|
|
parents[i] = &MerkleTreeNode{}
|
|
parents[i].leftChild = leaves[i*2]
|
|
leaves[i*2].parent = parents[i]
|
|
|
|
if i*2+1 == len(leaves) {
|
|
parents[i].rightChild = parents[i].leftChild
|
|
} else {
|
|
parents[i].rightChild = leaves[i*2+1]
|
|
leaves[i*2+1].parent = parents[i]
|
|
}
|
|
|
|
b1 := parents[i].leftChild.hash.BytesBE()
|
|
b2 := parents[i].rightChild.hash.BytesBE()
|
|
b1 = append(b1, b2...)
|
|
parents[i].hash = DoubleSha256(b1)
|
|
}
|
|
|
|
return buildMerkleTree(parents)
|
|
}
|
|
|
|
// MerkleTreeNode represents a node in the MerkleTree.
|
|
type MerkleTreeNode struct {
|
|
hash util.Uint256
|
|
parent *MerkleTreeNode
|
|
leftChild *MerkleTreeNode
|
|
rightChild *MerkleTreeNode
|
|
}
|
|
|
|
// IsLeaf returns whether this node is a leaf node or not.
|
|
func (n *MerkleTreeNode) IsLeaf() bool {
|
|
return n.leftChild == nil && n.rightChild == nil
|
|
}
|
|
|
|
// IsRoot returns whether this node is a root node or not.
|
|
func (n *MerkleTreeNode) IsRoot() bool {
|
|
return n.parent == nil
|
|
}
|