lbcd/claimtrie/node/hashfunc.go

package node

import "github.com/btcsuite/btcd/chaincfg/chainhash"

func HashMerkleBranches(left *chainhash.Hash, right *chainhash.Hash) *chainhash.Hash {
	// Concatenate the left and right nodes.
	var hash [chainhash.HashSize * 2]byte
	copy(hash[:chainhash.HashSize], left[:])
	copy(hash[chainhash.HashSize:], right[:])

	newHash := chainhash.DoubleHashH(hash[:])
	return &newHash
}

func ComputeMerkleRoot(hashes []*chainhash.Hash) *chainhash.Hash {
	if len(hashes) <= 0 {
		return nil
	}
	for len(hashes) > 1 {
		if (len(hashes) & 1) > 0 { // odd count
			hashes = append(hashes, hashes[len(hashes)-1])
		}
		for i := 0; i < len(hashes); i += 2 { // TODO: parallelize this loop (or use a lib that does it)
			hashes[i>>1] = HashMerkleBranches(hashes[i], hashes[i+1])
		}
		hashes = hashes[:len(hashes)>>1]
	}
	return hashes[0]
}