68 lines
1.3 KiB
Go
68 lines
1.3 KiB
Go
package bc
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import (
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"crypto/sha256"
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)
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// MerkleTree represent a Merkle tree
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type MerkleTree struct {
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RootNode *MerkleNode
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}
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// MerkleNode represent a Merkle tree node
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type MerkleNode struct {
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Left *MerkleNode
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Right *MerkleNode
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Data []byte
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}
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// NewMerkleTree creates a new Merkle tree from a sequence of data
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func NewMerkleTree(data [][]byte) *MerkleTree {
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var nodes []MerkleNode
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// append node until number is power of 2
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for (len(data) & (len(data) - 1)) != 0 {
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data = append(data, data[len(data)-1])
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}
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for _, datum := range data {
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node := NewMerkleNode(nil, nil, datum)
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nodes = append(nodes, *node)
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}
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// up level until there is only 1 node
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for len(nodes) > 1 {
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var newLevel []MerkleNode
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for j := 0; j < len(nodes); j += 2 {
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node := NewMerkleNode(&nodes[j], &nodes[j+1], nil)
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newLevel = append(newLevel, *node)
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}
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nodes = newLevel
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}
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mTree := MerkleTree{&nodes[0]}
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return &mTree
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}
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// NewMerkleNode creates a new Merkle tree node
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func NewMerkleNode(left, right *MerkleNode, data []byte) *MerkleNode {
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mNode := MerkleNode{}
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if left == nil && right == nil {
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hash := sha256.Sum256(data)
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mNode.Data = hash[:]
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} else {
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prevHashes := append(left.Data, right.Data...)
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hash := sha256.Sum256(prevHashes)
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mNode.Data = hash[:]
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}
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mNode.Left = left
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mNode.Right = right
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return &mNode
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}
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