feat&perf: reversed bit of key when persisting zktrie (#410)

* bit reverse when persisting zktrie

* fix according to review

* Update version.go

---------

Co-authored-by: HAOYUatHZ <37070449+HAOYUatHZ@users.noreply.github.com>

params/version.go

@@ -23,8 +23,8 @@ import (
 
 const (
 	VersionMajor = 4         // Major version component of the current release
-	VersionMinor = 2         // Minor version component of the current release
+	VersionMinor = 3         // Minor version component of the current release
-	VersionPatch = 11        // Patch version component of the current release
+	VersionPatch = 0         // Patch version component of the current release
 	VersionMeta  = "sepolia" // Version metadata to append to the version string
 )
 

trie/zk_trie_database.go

@@ -11,7 +11,13 @@ import (
 	"github.com/scroll-tech/go-ethereum/ethdb"
 )
 
-// ZktrieDatabase Database adaptor imple zktrie.ZktrieDatbase
+// ZktrieDatabase Database adaptor implements zktrie.ZktrieDatbase
+// It also reverses the bit order of the key being persisted.
+// This ensures that the adjacent leaf in zktrie maintains minimal
+// distance when persisted with dictionary order in LevelDB.
+// Consequently, this optimizes the snapshot operation, allowing it
+// to iterate through adjacent leaves at a reduced cost.
+
 type ZktrieDatabase struct {
 	db     *Database
 	prefix []byte
@@ -29,6 +35,7 @@ func NewZktrieDatabaseFromTriedb(db *Database) *ZktrieDatabase {
 
 // Put saves a key:value into the Storage
 func (l *ZktrieDatabase) Put(k, v []byte) error {
+	k = bitReverse(k)
 	l.db.lock.Lock()
 	l.db.rawDirties.Put(Concat(l.prefix, k[:]), v)
 	l.db.lock.Unlock()
@@ -37,6 +44,7 @@ func (l *ZktrieDatabase) Put(k, v []byte) error {
 
 // Get retrieves a value from a key in the Storage
 func (l *ZktrieDatabase) Get(key []byte) ([]byte, error) {
+	key = bitReverse(key)
 	concatKey := Concat(l.prefix, key[:])
 	l.db.lock.RLock()
 	value, ok := l.db.rawDirties.Get(concatKey)
@@ -78,7 +86,7 @@ func (l *ZktrieDatabase) Iterate(f func([]byte, []byte) (bool, error)) error {
 	iter := l.db.diskdb.NewIterator(l.prefix, nil)
 	defer iter.Release()
 	for iter.Next() {
-		localKey := iter.Key()[len(l.prefix):]
+		localKey := bitReverse(iter.Key()[len(l.prefix):])
 		if cont, err := f(localKey, iter.Value()); err != nil {
 			return err
 		} else if !cont {
@@ -109,3 +117,54 @@ func (l *ZktrieDatabase) List(limit int) ([]KV, error) {
 	})
 	return ret, err
 }
+
+func bitReverseForNibble(b byte) byte {
+	switch b {
+	case 0:
+		return 0
+	case 1:
+		return 8
+	case 2:
+		return 4
+	case 3:
+		return 12
+	case 4:
+		return 2
+	case 5:
+		return 10
+	case 6:
+		return 6
+	case 7:
+		return 14
+	case 8:
+		return 1
+	case 9:
+		return 9
+	case 10:
+		return 5
+	case 11:
+		return 13
+	case 12:
+		return 3
+	case 13:
+		return 11
+	case 14:
+		return 7
+	case 15:
+		return 15
+	default:
+		panic("unexpected input")
+	}
+}
+
+func bitReverse(inp []byte) (out []byte) {
+
+	l := len(inp)
+	out = make([]byte, l)
+
+	for i, b := range inp {
+		out[l-i-1] = bitReverseForNibble(b&15)<<4 + bitReverseForNibble(b>>4)
+	}
+
+	return
+}

trie/zk_trie_database_test.go

@@ -0,0 +1,69 @@
+package trie
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/scroll-tech/go-ethereum/common"
+)
+
+// grep from `feat/snap`
+func reverseBitInPlace(b []byte) {
+	var v [8]uint8
+	for i := 0; i < len(b); i++ {
+		for j := 0; j < 8; j++ {
+			v[j] = (b[i] >> j) & 1
+		}
+		var tmp uint8 = 0
+		for j := 0; j < 8; j++ {
+			tmp |= v[8-j-1] << j
+		}
+		b[i] = tmp
+	}
+}
+
+func reverseBytesInPlace(b []byte) {
+	for i, j := 0, len(b)-1; i < j; i, j = i+1, j-1 {
+		b[i], b[j] = b[j], b[i]
+	}
+}
+
+func TestBitReverse(t *testing.T) {
+
+	for _, testBytes := range [][]byte{
+		common.FromHex("7b908cce3bc16abb3eac5dff6c136856526f15225f74ce860a2bec47912a5492"),
+		common.FromHex("fac65cd2ad5e301083d0310dd701b5faaff1364cbe01cdbfaf4ec3609bb4149e"),
+		common.FromHex("55791f6ec2f83fee512a2d3d4b505784fdefaea89974e10440d01d62a18a298a"),
+		common.FromHex("5ab775b64d86a8058bb71c3c765d0f2158c14bbeb9cb32a65eda793a7e95e30f"),
+		common.FromHex("ccb464abf67804538908c62431b3a6788e8dc6dee62aff9bfe6b10136acfceac"),
+		common.FromHex("b908adff17a5aa9d6787324c39014a74b04cef7fba6a92aeb730f48da1ca665d"),
+	} {
+
+		b1 := bitReverse(testBytes)
+		reverseBitInPlace(testBytes)
+		reverseBytesInPlace(testBytes)
+		if !bytes.Equal(b1, testBytes) {
+			t.Errorf("unexpected bit reversed %x vs %x", b1, testBytes)
+		}
+	}
+
+}
+
+func TestBitDoubleReverse(t *testing.T) {
+
+	for _, testBytes := range [][]byte{
+		common.FromHex("7b908cce3bc16abb3eac5dff6c136856526f15225f74ce860a2bec47912a5492"),
+		common.FromHex("fac65cd2ad5e301083d0310dd701b5faaff1364cbe01cdbfaf4ec3609bb4149e"),
+		common.FromHex("55791f6ec2f83fee512a2d3d4b505784fdefaea89974e10440d01d62a18a298a"),
+		common.FromHex("5ab775b64d86a8058bb71c3c765d0f2158c14bbeb9cb32a65eda793a7e95e30f"),
+		common.FromHex("ccb464abf67804538908c62431b3a6788e8dc6dee62aff9bfe6b10136acfceac"),
+		common.FromHex("b908adff17a5aa9d6787324c39014a74b04cef7fba6a92aeb730f48da1ca665d"),
+	} {
+
+		b := bitReverse(bitReverse(testBytes))
+		if !bytes.Equal(b, testBytes) {
+			t.Errorf("unexpected double bit reversed %x vs %x", b, testBytes)
+		}
+	}
+
+}