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package blockchain |
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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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if len(data)%2 != 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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for i := 0; i < len(data)/2; i++ { |
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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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