rlp: support for uint256

rlp/decode.go

@@ -904,8 +904,7 @@ func (s *Stream) decodeUint256(dst *uint256.Int) error {
 		// Avoid zero-length read.
 		s.kind = -1
 	case size <= uint64(len(s.uintbuf)):
-		// For integers smaller than s.uintbuf, allocating a buffer
-		// can be avoided.
+		// All possible uint256 values fit into s.uintbuf.
 		buffer = s.uintbuf[:size]
 		if err := s.readFull(buffer); err != nil {
 			return err

rlp/encbuffer.go

@@ -172,8 +172,8 @@ func (w *encBuffer) writeBigInt(i *big.Int) {
 	}
 }
 
-// writeU256Int writes i as a uint256.Int.
-func (w *encBuffer) writeU256Int(z *uint256.Int) {
+// writeUint256 writes z as an integer.
+func (w *encBuffer) writeUint256(z *uint256.Int) {
 	bitlen := z.BitLen()
 	if bitlen <= 64 {
 		w.writeUint64(z.Uint64())
@@ -396,6 +396,11 @@ func (w EncoderBuffer) WriteBigInt(i *big.Int) {
 	w.buf.writeBigInt(i)
 }
 
+// WriteUint256 encodes uint256.Int as an RLP string.
+func (w EncoderBuffer) WriteUint256(i *big.Int) {
+	w.buf.writeUint256(i)
+}
+
 // WriteBytes encodes b as an RLP string.
 func (w EncoderBuffer) WriteBytes(b []byte) {
 	w.buf.writeBytes(b)

rlp/encode.go

@@ -217,13 +217,13 @@ func writeU256IntPtr(val reflect.Value, w *encBuffer) error {
 		w.str = append(w.str, 0x80)
 		return nil
 	}
-	w.writeU256Int(ptr)
+	w.writeUint256(ptr)
 	return nil
 }
 
 func writeU256IntNoPtr(val reflect.Value, w *encBuffer) error {
 	i := val.Interface().(uint256.Int)
-	w.writeU256Int(&i)
+	w.writeUint256(&i)
 	return nil
 }