RLP { public static byte[] encodeListHeader(int size) { if (size == 0) { return new byte[]{(byte) OFFSET_SHORT_LIST}; } int totalLength = size; byte[] header; if (totalLength < SIZE_THRESHOLD) { header = new byte[1]; header[0] = (byte) (OFFSET_SHORT_LIST + totalLength); } else { int tmpLength = totalLength; byte byteNum = 0; while (tmpLength != 0) { ++byteNum; tmpLength = tmpLength >> 8; } tmpLength = totalLength; byte[] lenBytes = new byte[byteNum]; for (int i = 0; i < byteNum; ++i) { lenBytes[byteNum - 1 - i] = (byte) ((tmpLength >> (8 * i)) & 0xFF); } header = new byte[1 + lenBytes.length]; header[0] = (byte) (OFFSET_LONG_LIST + byteNum); System.arraycopy(lenBytes, 0, header, 1, lenBytes.length); } return header; }  static int decodeInt(byte[] data, int index); static BigInteger decodeBigInteger(byte[] data, int index); static byte[] decodeIP4Bytes(byte[] data, int index); static int getFirstListElement(byte[] payload, int pos); static int getNextElementIndex(byte[] payload, int pos); static void fullTraverse(byte[] msgData, int level, int startPos,
                                    int endPos, int levelToIndex, Queue<Integer> index); static byte getCommandCode(byte[] data); static RLPList decode2(byte[] msgData); static DecodeResult decode(byte[] data, int pos); static byte[] encode(Object input); static byte[] encodeLength(int length, int offset); static byte[] encodeByte(byte singleByte); static byte[] encodeShort(short singleShort); static byte[] encodeInt(int singleInt); static byte[] encodeString(String srcString); static byte[] encodeBigInteger(BigInteger srcBigInteger); static byte[] encodeElement(byte[] srcData); static int calcElementPrefixSize(byte[] srcData); static byte[] encodeListHeader(int size); static byte[] encodeLongElementHeader(int length); static byte[] encodeSet(Set<ByteArrayWrapper> data); static byte[] encodeList(byte[]... elements);  }
@Test public void testEncodeListHeader(){ byte[] header = RLP.encodeListHeader(10); String expected_1 = "ca"; assertEquals(expected_1, Hex.toHexString(header)); header = RLP.encodeListHeader(1000); String expected_2 = "f903e8"; assertEquals(expected_2, Hex.toHexString(header)); header = RLP.encodeListHeader(1000000000); String expected_3 = "fb3b9aca00"; assertEquals(expected_3, Hex.toHexString(header)); }