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48 lines
969 B

package merkle
import (
"hash"
"github.com/tendermint/tendermint/crypto/tmhash"
)
// TODO: make these have a large predefined capacity
var (
leafPrefix = []byte{0}
innerPrefix = []byte{1}
)
// returns tmhash(<empty>)
func emptyHash() []byte {
return tmhash.Sum([]byte{})
}
// returns tmhash(0x00 || leaf)
func leafHash(leaf []byte) []byte {
return tmhash.Sum(append(leafPrefix, leaf...))
}
// returns tmhash(0x00 || leaf)
func leafHashOpt(s hash.Hash, leaf []byte) []byte {
s.Reset()
s.Write(leafPrefix)
s.Write(leaf)
return s.Sum(nil)
}
// returns tmhash(0x01 || left || right)
func innerHash(left []byte, right []byte) []byte {
data := make([]byte, len(innerPrefix)+len(left)+len(right))
n := copy(data, innerPrefix)
n += copy(data[n:], left)
copy(data[n:], right)
return tmhash.Sum(data)
}
func innerHashOpt(s hash.Hash, left []byte, right []byte) []byte {
s.Reset()
s.Write(innerPrefix)
s.Write(left)
s.Write(right)
return s.Sum(nil)
}