You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

94 lines
2.0 KiB

package merkle
import (
"bytes"
amino "github.com/tendermint/go-amino"
"github.com/tendermint/tendermint/crypto/tmhash"
cmn "github.com/tendermint/tendermint/libs/common"
)
// Merkle tree from a map.
// Leaves are `hash(key) | hash(value)`.
// Leaves are sorted before Merkle hashing.
type simpleMap struct {
kvs cmn.KVPairs
sorted bool
}
func newSimpleMap() *simpleMap {
return &simpleMap{
kvs: nil,
sorted: false,
}
}
// Set creates a kv pair of the key and the hash of the value,
// and then appends it to simpleMap's kv pairs.
func (sm *simpleMap) Set(key string, value []byte) {
sm.sorted = false
// The value is hashed, so you can
// check for equality with a cached value (say)
// and make a determination to fetch or not.
vhash := tmhash.Sum(value)
sm.kvs = append(sm.kvs, cmn.KVPair{
Key: []byte(key),
Value: vhash,
})
}
// Hash Merkle root hash of items sorted by key
// (UNSTABLE: and by value too if duplicate key).
func (sm *simpleMap) Hash() []byte {
sm.Sort()
return hashKVPairs(sm.kvs)
}
func (sm *simpleMap) Sort() {
if sm.sorted {
return
}
sm.kvs.Sort()
sm.sorted = true
}
// Returns a copy of sorted KVPairs.
// NOTE these contain the hashed key and value.
func (sm *simpleMap) KVPairs() cmn.KVPairs {
sm.Sort()
kvs := make(cmn.KVPairs, len(sm.kvs))
copy(kvs, sm.kvs)
return kvs
}
//----------------------------------------
// A local extension to KVPair that can be hashed.
// Key and value are length prefixed and concatenated,
// then hashed.
type KVPair cmn.KVPair
// Bytes returns key || value, with both the
// key and value length prefixed.
func (kv KVPair) Bytes() []byte {
var b bytes.Buffer
err := amino.EncodeByteSlice(&b, kv.Key)
if err != nil {
panic(err)
}
err = amino.EncodeByteSlice(&b, kv.Value)
if err != nil {
panic(err)
}
return b.Bytes()
}
func hashKVPairs(kvs cmn.KVPairs) []byte {
kvsH := make([][]byte, len(kvs))
for i, kvp := range kvs {
kvsH[i] = KVPair(kvp).Bytes()
}
return SimpleHashFromByteSlices(kvsH)
}