core/state: optimize some internals during encoding (ethereum#20038)

common/bytes.go

@@ -132,3 +132,14 @@ func LeftPadBytes(slice []byte, l int) []byte {
 
 	return padded
 }
+
+// TrimLeftZeroes returns a subslice of s without leading zeroes
+func TrimLeftZeroes(s []byte) []byte {
+	idx := 0
+	for ; idx < len(s); idx++ {
+		if s[idx] != 0 {
+			break
+		}
+	}
+	return s[idx:]
+}

core/state/state_object.go

@@ -282,7 +282,7 @@ func (s *stateObject) updateTrie(db Database) Trie {
 			continue
 		}
 		// Encoding []byte cannot fail, ok to ignore the error.
-		v, _ := rlp.EncodeToBytes(bytes.TrimLeft(value[:], "\x00"))
+		v, _ := rlp.EncodeToBytes(common.TrimLeftZeroes(value[:]))
 		s.setError(tr.TryUpdate(key[:], v))
 	}
 	return tr

core/state/state_object_test.go

@@ -0,0 +1,48 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package state
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/XinFinOrg/XDPoSChain/common"
+)
+
+func BenchmarkCutOriginal(b *testing.B) {
+	value := common.HexToHash("0x01")
+	for i := 0; i < b.N; i++ {
+		bytes.TrimLeft(value[:], "\x00")
+	}
+}
+
+func BenchmarkCutsetterFn(b *testing.B) {
+	value := common.HexToHash("0x01")
+	cutSetFn := func(r rune) bool {
+		return int32(r) == int32(0)
+	}
+	for i := 0; i < b.N; i++ {
+		bytes.TrimLeftFunc(value[:], cutSetFn)
+	}
+}
+
+func BenchmarkCutCustomTrim(b *testing.B) {
+	value := common.HexToHash("0x01")
+	for i := 0; i < b.N; i++ {
+		common.TrimLeftZeroes(value[:])
+	}
+}