Fixed rlp encoding extra leading zeros on uint64

When a uint64 fits perfectly in a multiple 8 bits, a leading zero was being added to the encoded value, for example 233 was encoded (prefix elided) as `00 e9` while it should have been `e9` Simply changed the way the amount of byte required is computed so the right amount of leading zeros is correctly removed after encoding. For uint64 value <= 255, this will even save an allocation since we will more often enter the `encodeUint8` case which is faster (theorically). Signed-off-by: Matthieu Vachon <[email protected]>
hyperledger-archives · May 19, 2021 · 9b4113e · 9b4113e
1 parent 97c7eda
commit 9b4113e
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Showing 2 changed files with 10 additions and 9 deletions.
diff --git a/encoding/rlp/rlp.go b/encoding/rlp/rlp.go
@@ -126,13 +126,14 @@ func encodeUint8(input uint8) ([]byte, error) {
 }
 
 func encodeUint64(i uint64) ([]byte, error) {
-	size := bits.Len64(i)/8 + 1
-	if size == 1 {
+	// Byte-wise ceiling
+	byteCount := (bits.Len64(i) + 7) / 8
+	if byteCount == 1 {
 		return encodeUint8(uint8(i))
 	}
 	b := make([]byte, 8)
 	binary.BigEndian.PutUint64(b, uint64(i))
-	return encodeString(b[8-size:])
+	return encodeString(b[8-byteCount:])
 }
 
 func encodeBigInt(b *big.Int) ([]byte, error) {

diff --git a/encoding/rlp/rlp_test.go b/encoding/rlp/rlp_test.go
@@ -129,14 +129,14 @@ func TestEncoding(t *testing.T) {
 	t.Run("Integers", func(t *testing.T) {
 		var tests = []testCase{
 			{
-				[]uint64{23, 30400},
-				[]byte{0xc4, 0x17, 0x82, 0x76, 0xc0},
-				[][]byte{{23}, {0x76, 0xc0}},
+				[]uint64{23, 233, 30400},
+				[]byte{0xc6, 0x17, 0x81, 0xe9, 0x82, 0x76, 0xc0},
+				[][]byte{{23}, {233}, {0x76, 0xc0}},
 			},
 			{
-				[]*big.Int{big.NewInt(23), big.NewInt(30400)},
-				[]byte{0xc4, 0x17, 0x82, 0x76, 0xc0},
-				[][]byte{{23}, {0x76, 0xc0}},
+				[]*big.Int{big.NewInt(23), big.NewInt(233), big.NewInt(30400)},
+				[]byte{0xc6, 0x17, 0x81, 0xe9, 0x82, 0x76, 0xc0},
+				[][]byte{{23}, {233}, {0x76, 0xc0}},
 			},
 		}