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58 lines
1.4 KiB
58 lines
1.4 KiB
package merkle
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import (
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"github.com/tendermint/go-crypto/tmhash"
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)
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// SimpleHashFromTwoHashes is the basic operation of the Merkle tree: Hash(left | right).
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func SimpleHashFromTwoHashes(left, right []byte) []byte {
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var hasher = tmhash.New()
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err := encodeByteSlice(hasher, left)
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if err != nil {
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panic(err)
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}
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err = encodeByteSlice(hasher, right)
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if err != nil {
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panic(err)
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}
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return hasher.Sum(nil)
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}
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// SimpleHashFromHashers computes a Merkle tree from items that can be hashed.
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func SimpleHashFromHashers(items []Hasher) []byte {
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hashes := make([][]byte, len(items))
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for i, item := range items {
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hash := item.Hash()
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hashes[i] = hash
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}
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return simpleHashFromHashes(hashes)
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}
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// SimpleHashFromMap computes a Merkle tree from sorted map.
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// Like calling SimpleHashFromHashers with
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// `item = []byte(Hash(key) | Hash(value))`,
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// sorted by `item`.
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func SimpleHashFromMap(m map[string]Hasher) []byte {
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sm := newSimpleMap()
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for k, v := range m {
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sm.Set(k, v)
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}
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return sm.Hash()
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}
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//----------------------------------------------------------------
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// Expects hashes!
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func simpleHashFromHashes(hashes [][]byte) []byte {
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// Recursive impl.
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switch len(hashes) {
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case 0:
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return nil
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case 1:
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return hashes[0]
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default:
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left := simpleHashFromHashes(hashes[:(len(hashes)+1)/2])
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right := simpleHashFromHashes(hashes[(len(hashes)+1)/2:])
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return SimpleHashFromTwoHashes(left, right)
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}
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}
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