package merkle
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import (
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"github.com/tendermint/go-wire"
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cmn "github.com/tendermint/tmlibs/common"
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"golang.org/x/crypto/ripemd160"
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)
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type SimpleMap struct {
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kvs cmn.KVPairs
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sorted bool
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}
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func NewSimpleMap() *SimpleMap {
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return &SimpleMap{
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kvs: nil,
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sorted: false,
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}
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}
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func (sm *SimpleMap) Set(key string, value Hasher) {
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sm.sorted = false
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// Hash the key to blind it... why not?
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khash := SimpleHashFromBytes([]byte(key))
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// And the value is hashed too, so you can
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// check for equality with a cached value (say)
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// and make a determination to fetch or not.
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vhash := value.Hash()
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sm.kvs = append(sm.kvs, cmn.KVPair{
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Key: khash,
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Value: vhash,
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})
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}
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// Merkle root hash of items sorted by key
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// (UNSTABLE: and by value too if duplicate key).
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func (sm *SimpleMap) Hash() []byte {
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sm.Sort()
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return hashKVPairs(sm.kvs)
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}
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func (sm *SimpleMap) Sort() {
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if sm.sorted {
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return
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}
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sm.kvs.Sort()
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sm.sorted = true
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}
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// Returns a copy of sorted KVPairs.
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func (sm *SimpleMap) KVPairs() cmn.KVPairs {
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sm.Sort()
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kvs := make(cmn.KVPairs, len(sm.kvs))
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copy(kvs, sm.kvs)
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return kvs
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}
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//----------------------------------------
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// A local extension to KVPair that can be hashed.
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type kvPair cmn.KVPair
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func (kv kvPair) Hash() []byte {
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hasher := ripemd160.New()
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err := wire.EncodeByteSlice(hasher, kv.Key)
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if err != nil {
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panic(err)
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}
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err = wire.EncodeByteSlice(hasher, kv.Value)
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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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func hashKVPairs(kvs cmn.KVPairs) []byte {
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kvsH := make([]Hasher, 0, len(kvs))
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for _, kvp := range kvs {
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kvsH = append(kvsH, kvPair(kvp))
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}
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return SimpleHashFromHashers(kvsH)
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}
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