package org.ethereum.util;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Queue;
import static java.util.Arrays.copyOfRange;
import static org.ethereum.util.ByteUtil.byteArrayToInt;
import static org.spongycastle.util.Arrays.concatenate;
import static org.spongycastle.util.BigIntegers.asUnsignedByteArray;
import java.util.List;
import org.ethereum.util.RLP;
import org.ethereum.util.RLPItem;
import org.ethereum.util.RLPList;
/**
* Recursive Length Prefix (RLP) encoding.
*
* The purpose of RLP is to encode arbitrarily nested arrays of binary data, and
* RLP is the main encoding method used to serialize objects in Ethereum. The
* only purpose of RLP is to encode structure; encoding specific atomic data
* types (eg. strings, ints, floats) is left up to higher-order protocols; in
* Ethereum the standard is that integers are represented in big endian binary
* form. If one wishes to use RLP to encode a dictionary, the two suggested
* canonical forms are to either use [[k1,v1],[k2,v2]...] with keys in
* lexicographic order or to use the higher-level Patricia Tree encoding as
* Ethereum does.
*
* The RLP encoding function takes in an item. An item is defined as follows:
*
* - A string (ie. byte array) is an item - A list of items is an item
*
* For example, an empty string is an item, as is the string containing the word
* "cat", a list containing any number of strings, as well as more complex data
* structures like ["cat",["puppy","cow"],"horse",[[]],"pig",[""],"sheep"]. Note
* that in the context of the rest of this article, "string" will be used as a
* synonym for "a certain number of bytes of binary data"; no special encodings
* are used and no knowledge about the content of the strings is implied.
*
* See: https://github.com/ethereum/wiki/wiki/%5BEnglish%5D-RLP
*
* www.ethereumJ.com
* @author: Roman Mandeleil
* Created on: 01/04/2014 10:45
*
*/
public class RLP {
/** Allow for content up to size of 2^64 bytes **/
private static double MAX_ITEM_LENGTH = Math.pow(256, 8);
/**
* Reason for threshold according to Vitalik Buterin:
* - 56 bytes maximizes the benefit of both options
* - if we went with 60 then we would have only had 4 slots for long strings
* so RLP would not have been able to store objects above 4gb
* - if we went with 48 then RLP would be fine for 2^128 space, but that's way too much
* - so 56 and 2^64 space seems like the right place to put the cutoff
* - also, that's where Bitcoin's varint does the cutof
**/
private static int SIZE_THRESHOLD = 56;
/** RLP encoding rules are defined as follows: */
/*
* For a single byte whose value is in the [0x00, 0x7f] range, that byte is
* its own RLP encoding.
*/
/**
* [0x80]
* If a string is 0-55 bytes long, the RLP encoding consists of a single
* byte with value 0x80 plus the length of the string followed by the
* string. The range of the first byte is thus [0x80, 0xb7].
*/
private static int OFFSET_SHORT_ITEM = 0x80;
/**
* [0xb7]
* If a string is more than 55 bytes long, the RLP encoding consists of a
* single byte with value 0xb7 plus the length of the length of the string
* in binary form, followed by the length of the string, followed by the
* string. For example, a length-1024 string would be encoded as
* \xb9\x04\x00 followed by the string. The range of the first byte is thus
* [0xb8, 0xbf].
*/
private static int OFFSET_LONG_ITEM = 0xb7;
/**
* [0xc0]
* If the total payload of a list (i.e. the combined length of all its
* items) is 0-55 bytes long, the RLP encoding consists of a single byte
* with value 0xc0 plus the length of the list followed by the concatenation
* of the RLP encodings of the items. The range of the first byte is thus
* [0xc0, 0xf7].
*/
private static int OFFSET_SHORT_LIST = 0xc0;
/**
* [0xf7]
* If the total payload of a list is more than 55 bytes long, the RLP
* encoding consists of a single byte with value 0xf7 plus the length of the
* length of the list in binary form, followed by the length of the list,
* followed by the concatenation of the RLP encodings of the items. The
* range of the first byte is thus [0xf8, 0xff].
*/
private static int OFFSET_LONG_LIST = 0xf7;
/* ******************************************************
* DECODING *
* ******************************************************/
private static byte decodeOneByteItem(byte[] data, int index) {
// null item
if ((data[index] & 0xFF) == OFFSET_SHORT_ITEM) {
return (byte) (data[index] - OFFSET_SHORT_ITEM);
}
// single byte item
if ((data[index] & 0xFF) < OFFSET_SHORT_ITEM) {
return (byte) (data[index]);
}
// single byte item
if ((data[index] & 0xFF) == OFFSET_SHORT_ITEM + 1) {
return (byte) (data[index + 1]);
}
return 0;
}
public static int decodeInt(byte[] data, int index) {
int value = 0;
if ((data[index] & 0xFF) > OFFSET_SHORT_ITEM
&& (data[index] & 0xFF) < OFFSET_LONG_ITEM) {
byte length = (byte) (data[index] - OFFSET_SHORT_ITEM);
byte pow = (byte) (length - 1);
for (int i = 1; i <= length; ++i) {
value += data[index + i] << (8 * pow);
pow--;
}
} else {
throw new RuntimeException("wrong decode attempt");
}
return value;
}
private static short decodeShort(byte[] data, int index) {
short value = 0;
if ((data[index] & 0xFF) > OFFSET_SHORT_ITEM
&& (data[index] & 0xFF) < OFFSET_LONG_ITEM) {
byte length = (byte) (data[index] - OFFSET_SHORT_ITEM);
value = ByteBuffer.wrap(data, index, length).getShort();
} else {
value = data[index];
}
return value;
}
private static long decodeLong(byte[] data, int index) {
long value = 0;
if ((data[index] & 0xFF) > OFFSET_SHORT_ITEM
&& (data[index] & 0xFF) < OFFSET_LONG_ITEM) {
byte length = (byte) (data[index] - OFFSET_SHORT_ITEM);
byte pow = (byte) (length - 1);
for (int i = 1; i <= length; ++i) {
value += data[index + i] << (8 * pow);
pow--;
}
} else {
throw new RuntimeException("wrong decode attempt");
}
return value;
}
private static String decodeStringItem(byte[] data, int index) {
String value = null;
if ((data[index] & 0xFF) >= OFFSET_LONG_ITEM
&& (data[index] & 0xFF) < OFFSET_SHORT_LIST) {
byte lengthOfLength = (byte) (data[index] - OFFSET_LONG_ITEM);
int length = calcLengthRaw(lengthOfLength, data, index);
value = new String(data, index + lengthOfLength + 1, length);
} else if ((data[index] & 0xFF) > OFFSET_SHORT_ITEM
&& (data[index] & 0xFF) < OFFSET_LONG_ITEM) {
byte length = (byte) ((data[index] & 0xFF) - OFFSET_SHORT_ITEM);
value = new String(data, index + 1, length);
} else {
throw new RuntimeException("wrong decode attempt");
}
return value;
}
private static byte[] decodeItemBytes(byte[] data, int index) {
byte[] value = null;
int length = 0;
if ((data[index] & 0xFF) >= OFFSET_LONG_ITEM
&& (data[index] & 0xFF) < OFFSET_SHORT_LIST) {
byte lengthOfLength = (byte) (data[index] - OFFSET_LONG_ITEM);
length = calcLengthRaw(lengthOfLength, data, index);
} else if ((data[index] & 0xFF) > OFFSET_SHORT_ITEM
&& (data[index] & 0xFF) < OFFSET_LONG_ITEM) {
length = (byte) (data[index] - OFFSET_SHORT_ITEM);
} else {
throw new RuntimeException("wrong decode attempt");
}
byte[] valueBytes = new byte[length];
System.arraycopy(data, index, valueBytes, 0, length);
value = valueBytes;
return value;
}
public static BigInteger decodeBigInteger(byte[] data, int index) {
BigInteger value = null;
int length = 0;
if ((data[index] & 0xFF) >= OFFSET_LONG_ITEM
&& (data[index] & 0xFF) < OFFSET_SHORT_LIST) {
byte lengthOfLength = (byte) (data[index] - OFFSET_LONG_ITEM);
length = calcLengthRaw(lengthOfLength, data, index);
} else if ((data[index] & 0xFF) > OFFSET_SHORT_ITEM
&& (data[index] & 0xFF) < OFFSET_LONG_ITEM) {
length = (byte) (data[index] - OFFSET_SHORT_ITEM);
} else {
throw new RuntimeException("wrong decode attempt");
}
byte[] valueBytes = new byte[length];
System.arraycopy(data, index, valueBytes, 0, length);
value = new BigInteger(1, valueBytes);
return value;
}
private static byte[] decodeByteArray(byte[] data, int index) {
byte[] value = null;
int length = 0;
if ((data[index] & 0xFF) >= OFFSET_LONG_ITEM
&& (data[index] & 0xFF) < OFFSET_SHORT_LIST) {
byte lengthOfLength = (byte) (data[index] - OFFSET_LONG_ITEM);
length = calcLengthRaw(lengthOfLength, data, index);
} else if ((data[index] & 0xFF) > OFFSET_SHORT_ITEM
&& (data[index] & 0xFF) < OFFSET_LONG_ITEM) {
length = (byte) (data[index] - OFFSET_SHORT_ITEM);
} else {
throw new RuntimeException("wrong decode attempt");
}
byte[] valueBytes = new byte[length];
System.arraycopy(data, index, valueBytes, 0, length);
value = valueBytes;
return value;
}
private static int nextItemLength(byte[] data, int index) {
if (index >= data.length)
return -1;
if ((data[index] & 0xFF) >= OFFSET_LONG_LIST) {
byte lengthOfLength = (byte) (data[index] - OFFSET_LONG_LIST);
int length = calcLength(lengthOfLength, data, index);
return length;
}
if ((data[index] & 0xFF) >= OFFSET_SHORT_LIST
&& (data[index] & 0xFF) < OFFSET_LONG_LIST) {
byte length = (byte) ((data[index] & 0xFF) - OFFSET_SHORT_LIST);
return length;
}
if ((data[index] & 0xFF) > OFFSET_LONG_ITEM
&& (data[index] & 0xFF) < OFFSET_SHORT_LIST) {
byte lengthOfLength = (byte) (data[index] - OFFSET_LONG_ITEM);
int length = calcLength(lengthOfLength, data, index);
return length;
}
if ((data[index] & 0xFF) > OFFSET_SHORT_ITEM
&& (data[index] & 0xFF) <= OFFSET_LONG_ITEM) {
byte length = (byte) ((data[index] & 0xFF) - OFFSET_SHORT_ITEM);
return length;
}
if ((data[index] & 0xFF) == OFFSET_SHORT_ITEM) {
return 1;
}
if ((data[index] & 0xFF) < OFFSET_SHORT_ITEM) {
return 1;
}
return -1;
}
public static byte[] decodeIP4Bytes(byte[] data, int index) {
int length = (data[index] & 0xFF) - OFFSET_SHORT_LIST;
int offset = 1;
byte aByte = decodeOneByteItem(data, index + offset);
if ((data[index + offset] & 0xFF) > OFFSET_SHORT_ITEM)
offset = offset + 2;
else
offset = offset + 1;
byte bByte = decodeOneByteItem(data, index + offset);
if ((data[index + offset] & 0xFF) > OFFSET_SHORT_ITEM)
offset = offset + 2;
else
offset = offset + 1;
byte cByte = decodeOneByteItem(data, index + offset);
if ((data[index + offset] & 0xFF) > OFFSET_SHORT_ITEM)
offset = offset + 2;
else
offset = offset + 1;
byte dByte = decodeOneByteItem(data, index + offset);
// return IP address
return new byte[] { aByte, bByte, cByte, dByte };
}
public static int getFirstListElement(byte[] payload, int pos) {
if (pos >= payload.length)
return -1;
if ((payload[pos] & 0xFF) >= OFFSET_LONG_LIST) {
byte lengthOfLength = (byte) (payload[pos] - OFFSET_LONG_LIST);
return pos + lengthOfLength + 1;
}
if ((payload[pos] & 0xFF) >= OFFSET_SHORT_LIST
&& (payload[pos] & 0xFF) < OFFSET_LONG_LIST) {
return pos + 1;
}
if ((payload[pos] & 0xFF) >= OFFSET_LONG_ITEM
&& (payload[pos] & 0xFF) < OFFSET_SHORT_LIST) {
byte lengthOfLength = (byte) (payload[pos] - OFFSET_LONG_ITEM);
return pos + lengthOfLength + 1;
}
return -1;
}
public static int getNextElementIndex(byte[] payload, int pos) {
if (pos >= payload.length)
return -1;
if ((payload[pos] & 0xFF) >= OFFSET_LONG_LIST) {
byte lengthOfLength = (byte) (payload[pos] - OFFSET_LONG_LIST);
int length = calcLength(lengthOfLength, payload, pos);
return pos + lengthOfLength + length + 1;
}
if ((payload[pos] & 0xFF) >= OFFSET_SHORT_LIST
&& (payload[pos] & 0xFF) < OFFSET_LONG_LIST) {
byte length = (byte) ((payload[pos] & 0xFF) - OFFSET_SHORT_LIST);
return pos + 1 + length;
}
if ((payload[pos] & 0xFF) >= OFFSET_LONG_ITEM
&& (payload[pos] & 0xFF) < OFFSET_SHORT_LIST) {
byte lengthOfLength = (byte) (payload[pos] - OFFSET_LONG_ITEM);
int length = calcLength(lengthOfLength, payload, pos);
return pos + lengthOfLength + length + 1;
}
if ((payload[pos] & 0xFF) > OFFSET_SHORT_ITEM
&& (payload[pos] & 0xFF) < OFFSET_LONG_ITEM) {
byte length = (byte) ((payload[pos] & 0xFF) - OFFSET_SHORT_ITEM);
return pos + 1 + length;
}
if ((payload[pos] & 0xFF) == OFFSET_SHORT_ITEM) {
return pos + 1;
}
if ((payload[pos] & 0xFF) < OFFSET_SHORT_ITEM) {
return pos + 1;
}
return -1;
}
/**
* Get exactly one message payload
*/
public static void fullTraverse(byte[] msgData, int level, int startPos,
int endPos, int levelToIndex, Queue<Integer> index) {
try {
if (msgData == null || msgData.length == 0)
return;
int pos = startPos;
while (pos < endPos) {
if (level == levelToIndex)
index.add(new Integer(pos));
// It's a list with a payload more than 55 bytes
// data[0] - 0xF7 = how many next bytes allocated
// for the length of the list
if ((msgData[pos] & 0xFF) >= OFFSET_LONG_LIST) {
byte lengthOfLength = (byte) (msgData[pos] - OFFSET_LONG_LIST);
int length = calcLength(lengthOfLength, msgData, pos);
// now we can parse an item for data[1]..data[length]
System.out.println("-- level: [" + level
+ "] Found big list length: " + length);
fullTraverse(msgData, level + 1, pos + lengthOfLength + 1,
pos + lengthOfLength + length, levelToIndex, index);
pos += lengthOfLength + length + 1;
continue;
}
// It's a list with a payload less than 55 bytes
if ((msgData[pos] & 0xFF) >= OFFSET_SHORT_LIST
&& (msgData[pos] & 0xFF) < OFFSET_LONG_LIST) {
byte length = (byte) ((msgData[pos] & 0xFF) - OFFSET_SHORT_LIST);
System.out.println("-- level: [" + level
+ "] Found small list length: " + length);
fullTraverse(msgData, level + 1, pos + 1, pos + length + 1,
levelToIndex, index);
pos += 1 + length;
continue;
}
// It's an item with a payload more than 55 bytes
// data[0] - 0xB7 = how much next bytes allocated for
// the length of the string
if ((msgData[pos] & 0xFF) >= OFFSET_LONG_ITEM
&& (msgData[pos] & 0xFF) < OFFSET_SHORT_LIST) {
byte lengthOfLength = (byte) (msgData[pos] - OFFSET_LONG_ITEM);
int length = calcLength(lengthOfLength, msgData, pos);
// now we can parse an item for data[1]..data[length]
System.out.println("-- level: [" + level
+ "] Found big item length: " + length);
pos += lengthOfLength + length + 1;
continue;
}
// It's an item less than 55 bytes long,
// data[0] - 0x80 == length of the item
if ((msgData[pos] & 0xFF) > OFFSET_SHORT_ITEM
&& (msgData[pos] & 0xFF) < OFFSET_LONG_ITEM) {
byte length = (byte) ((msgData[pos] & 0xFF) - OFFSET_SHORT_ITEM);
System.out.println("-- level: [" + level
+ "] Found small item length: " + length);
pos += 1 + length;
continue;
}
// null item
if ((msgData[pos] & 0xFF) == OFFSET_SHORT_ITEM) {
System.out.println("-- level: [" + level
+ "] Found null item: ");
pos += 1;
continue;
}
// single byte item
if ((msgData[pos] & 0xFF) < OFFSET_SHORT_ITEM) {
System.out.println("-- level: [" + level
+ "] Found single item: ");
pos += 1;
continue;
}
}
} catch (Throwable th) {
throw new RuntimeException("RLP wrong encoding",
th.fillInStackTrace());
}
}
private static int calcLength(int lengthOfLength, byte[] msgData, int pos) {
byte pow = (byte) (lengthOfLength - 1);
int length = 0;
for (int i = 1; i <= lengthOfLength; ++i) {
length += (msgData[pos + i] & 0xFF) << (8 * pow);
pow--;
}
return length;
}
private static int calcLengthRaw(int lengthOfLength, byte[] msgData, int index) {
byte pow = (byte) (lengthOfLength - 1);
int length = 0;
for (int i = 1; i <= lengthOfLength; ++i) {
length += msgData[index + i] << (8 * pow);
pow--;
}
return length;
}
public static byte getCommandCode(byte[] data) {
byte command = 0;
int index = getFirstListElement(data, 0);
command = data[index];
command = ((int) (command & 0xFF) == OFFSET_SHORT_ITEM) ? 0 : command;
return command;
}
/**
* Parse wire byte[] message into RLP elements
*
* @param msgData
* - raw RLP data
* @return rlpList
* - outcome of recursive RLP structure
*/
public static RLPList decode2(byte[] msgData) {
RLPList rlpList = new RLPList();
fullTraverse(msgData, 0, 0, msgData.length, 1, rlpList);
return rlpList;
}
/**
* Get exactly one message payload
*/
private static void fullTraverse(byte[] msgData, int level, int startPos,
int endPos, int levelToIndex, RLPList rlpList) {
try {
if (msgData == null || msgData.length == 0)
return;
int pos = startPos;
while (pos < endPos) {
// It's a list with a payload more than 55 bytes
// data[0] - 0xF7 = how many next bytes allocated
// for the length of the list
if ((msgData[pos] & 0xFF) > OFFSET_LONG_LIST) {
byte lengthOfLength = (byte) (msgData[pos] - OFFSET_LONG_LIST);
int length = calcLength(lengthOfLength, msgData, pos);
byte[] rlpData = new byte[lengthOfLength + length + 1];
System.arraycopy(msgData, pos, rlpData, 0, lengthOfLength
+ length + 1);
RLPList newLevelList = new RLPList();
newLevelList.setRLPData(rlpData);
fullTraverse(msgData, level + 1, pos + lengthOfLength + 1,
pos + lengthOfLength + length + 1, levelToIndex,
newLevelList);
rlpList.add(newLevelList);
pos += lengthOfLength + length + 1;
continue;
}
// It's a list with a payload less than 55 bytes
if ((msgData[pos] & 0xFF) >= OFFSET_SHORT_LIST
&& (msgData[pos] & 0xFF) <= OFFSET_LONG_LIST) {
byte length = (byte) ((msgData[pos] & 0xFF) - OFFSET_SHORT_LIST);
byte[] rlpData = new byte[length + 1];
System.arraycopy(msgData, pos, rlpData, 0, length + 1);
RLPList newLevelList = new RLPList();
newLevelList.setRLPData(rlpData);
if (length > 0)
fullTraverse(msgData, level + 1, pos + 1, pos + length
+ 1, levelToIndex, newLevelList);
rlpList.add(newLevelList);
pos += 1 + length;
continue;
}
// It's an item with a payload more than 55 bytes
// data[0] - 0xB7 = how much next bytes allocated for
// the length of the string
if ((msgData[pos] & 0xFF) > OFFSET_LONG_ITEM
&& (msgData[pos] & 0xFF) < OFFSET_SHORT_LIST) {
byte lengthOfLength = (byte) (msgData[pos] - OFFSET_LONG_ITEM);
int length = calcLength(lengthOfLength, msgData, pos);
// now we can parse an item for data[1]..data[length]
byte[] item = new byte[length];
System.arraycopy(msgData, pos + lengthOfLength + 1, item,
0, length);
byte[] rlpPrefix = new byte[lengthOfLength + 1];
System.arraycopy(msgData, pos, rlpPrefix, 0,
lengthOfLength + 1);
RLPItem rlpItem = new RLPItem(item);
rlpList.add(rlpItem);
pos += lengthOfLength + length + 1;
continue;
}
// It's an item less than 55 bytes long,
// data[0] - 0x80 == length of the item
if ((msgData[pos] & 0xFF) > OFFSET_SHORT_ITEM
&& (msgData[pos] & 0xFF) <= OFFSET_LONG_ITEM) {
byte length = (byte) ((msgData[pos] & 0xFF) - OFFSET_SHORT_ITEM);
byte[] item = new byte[length];
System.arraycopy(msgData, pos + 1, item, 0, length);
byte[] rlpPrefix = new byte[2];
System.arraycopy(msgData, pos, rlpPrefix, 0, 2);
RLPItem rlpItem = new RLPItem(item);
rlpList.add(rlpItem);
pos += 1 + length;
continue;
}
// null item
if ((msgData[pos] & 0xFF) == OFFSET_SHORT_ITEM) {
byte[] item = ByteUtil.EMPTY_BYTE_ARRAY;
RLPItem rlpItem = new RLPItem(item);
rlpList.add(rlpItem);
pos += 1;
continue;
}
// single byte item
if ((msgData[pos] & 0xFF) < OFFSET_SHORT_ITEM) {
byte[] item = { (byte) (msgData[pos] & 0xFF) };
RLPItem rlpItem = new RLPItem(item);
rlpList.add(rlpItem);
pos += 1;
continue;
}
}
} catch (Exception e) {
throw new RuntimeException("RLP wrong encoding", e);
}
}
/**
* Reads any RLP encoded byte-array and returns all objects as byte-array or list of byte-arrays
*
* @param data RLP encoded byte-array
* @param pos position in the array to start reading
* @return DecodeResult encapsulates the decoded items as a single Object and the final read position
*/
public static DecodeResult decode(byte[] data, int pos) {
if (data == null || data.length < 1) {
return null;
}
int prefix = data[pos] & 0xFF;
if (prefix == OFFSET_SHORT_ITEM) {
return new DecodeResult(pos+1, ""); // means no length or 0
} else if (prefix < OFFSET_SHORT_ITEM) {
return new DecodeResult(pos+1, new byte[] { data[pos] }); // byte is its own RLP encoding
} else if (prefix < OFFSET_LONG_ITEM) {
int len = prefix - OFFSET_SHORT_ITEM; // length of the encoded bytes
return new DecodeResult(pos+1+len, copyOfRange(data, pos+1, pos+1+len));
} else if (prefix < OFFSET_SHORT_LIST) {
int lenlen = prefix - OFFSET_LONG_ITEM; // length of length the encoded bytes
int lenbytes = byteArrayToInt(copyOfRange(data, pos+1, pos+1+lenlen)); // length of encoded bytes
return new DecodeResult(pos+1+lenlen+lenbytes, copyOfRange(data, pos+1+lenlen, pos+1+lenlen+lenbytes));
} else if (prefix <= OFFSET_LONG_LIST) {
int len = prefix - OFFSET_SHORT_LIST; // length of the encoded list
int prevPos = pos; pos++;
return decodeList(data, pos, prevPos, len);
} else if (prefix < 0xFF) {
int lenlen = prefix - OFFSET_LONG_LIST; // length of length the encoded list
int lenlist = byteArrayToInt(copyOfRange(data, pos+1, pos+1+lenlen)); // length of encoded bytes
pos = pos + lenlen + 1; // start at position of first element in list
int prevPos = lenlist;
return decodeList(data, pos, prevPos, lenlist);
} else {
throw new RuntimeException("Only byte values between 0x00 and 0xFF are supported, but got: " + prefix);
}
}
private static DecodeResult decodeList(byte[] data, int pos, int prevPos, int len) {
List<Object> slice = new ArrayList<>();
for (int i = 0; i < len;) {
// Get the next item in the data list and append it
DecodeResult result = decode(data, pos);
slice.add(result.getDecoded());
// Increment pos by the amount bytes in the previous read
prevPos = result.getPos();
i += (prevPos - pos);
pos = prevPos;
}
return new DecodeResult(pos, slice.toArray());
}
/* ******************************************************
* ENCODING *
* ******************************************************/
/**
* Turn Object into its RLP encoded equivalent of a byte-array
* Support for String, Integer, BigInteger and Lists of any of these types.
*
* @param input as object or List of objects
* @return byte[] RLP encoded
*/
public static byte[] encode(Object input) {
Value val = new Value(input);
if (val.isList()) {
List<Object> inputArray = val.asList();
if (inputArray.size() == 0) {
return encodeLength(inputArray.size(), OFFSET_SHORT_LIST);
}
byte[] output = ByteUtil.EMPTY_BYTE_ARRAY;
for (Object object : inputArray) {
output = concatenate(output, encode(object));
}
byte[] prefix = encodeLength(output.length, OFFSET_SHORT_LIST);
return concatenate(prefix, output);
} else {
byte[] inputAsBytes = toBytes(input);
if (inputAsBytes.length == 1) {
return inputAsBytes;
} else {
byte[] firstByte = encodeLength(inputAsBytes.length, OFFSET_SHORT_ITEM);
return concatenate(firstByte, inputAsBytes);
}
}
}
/** Integer limitation goes up to 2^31-1 so length can never be bigger than MAX_ITEM_LENGTH */
public static byte[] encodeLength(int length, int offset) {
if (length < SIZE_THRESHOLD) {
byte firstByte = (byte) (length + offset);
return new byte[] { firstByte };
} else if (length < MAX_ITEM_LENGTH) {
byte[] binaryLength;
if (length > 0xFF)
binaryLength = BigInteger.valueOf(length).toByteArray();
else
binaryLength = new byte[] { (byte) length };
byte firstByte = (byte) (binaryLength.length + offset + SIZE_THRESHOLD - 1);
return concatenate(new byte[] { firstByte }, binaryLength);
} else {
throw new RuntimeException("Input too long");
}
}
public static byte[] encodeByte(byte singleByte) {
if ((singleByte & 0xFF) == 0) {
return new byte[] { (byte) OFFSET_SHORT_ITEM };
} else if ((singleByte & 0xFF) < 0x7F) {
return new byte[] { singleByte };
} else {
return new byte[] { (byte) (OFFSET_SHORT_ITEM + 1), singleByte };
}
}
public static byte[] encodeShort(short singleShort) {
if (singleShort <= 0xFF)
return encodeByte((byte) singleShort);
else {
return new byte[] { (byte) (OFFSET_SHORT_ITEM + 2),
(byte) (singleShort >> 8 & 0xFF),
(byte) (singleShort >> 0 & 0xFF) };
}
}
public static byte[] encodeInt(int singleInt) {
if (singleInt <= 0xFF)
return encodeByte((byte) singleInt);
else if (singleInt <= 0xFFFF)
return encodeShort((short) singleInt);
else if (singleInt <= 0xFFFFFF)
return new byte[] { (byte) (OFFSET_SHORT_ITEM + 3),
(byte) (singleInt >>> 16),
(byte) (singleInt >>> 8),
(byte) singleInt};
else {
return new byte[] { (byte) (OFFSET_SHORT_ITEM + 4),
(byte) (singleInt >>> 24),
(byte) (singleInt >>> 16),
(byte) (singleInt >>> 8),
(byte) singleInt};
}
}
public static byte[] encodeString(String srcString) {
return encodeElement(srcString.getBytes());
}
public static byte[] encodeBigInteger(BigInteger srcBigInteger) {
if(srcBigInteger == BigInteger.ZERO)
return encodeByte((byte)0);
else
return encodeElement(asUnsignedByteArray(srcBigInteger));
}
public static byte[] encodeElement(byte[] srcData) {
if (srcData == null)
return new byte[]{(byte) OFFSET_SHORT_ITEM};
else if (srcData.length == 1 && (srcData[0] & 0xFF) < 0x80) {
return srcData;
} else if (srcData.length < SIZE_THRESHOLD) {
// length = 8X
byte length = (byte) (OFFSET_SHORT_ITEM + srcData.length);
byte[] data = Arrays.copyOf(srcData, srcData.length + 1);
System.arraycopy(data, 0, data, 1, srcData.length);
data[0] = length;
return data;
} else {
// length of length = BX
// prefix = [BX, [length]]
int tmpLength = srcData.length;
byte byteNum = 0;
while (tmpLength != 0) {
++byteNum;
tmpLength = tmpLength >> 8;
}
byte[] lenBytes = new byte[byteNum];
for (int i = 0; i < byteNum; ++i) {
lenBytes[byteNum - 1 - i] = (byte) ((srcData.length >> (8 * i)) & 0xFF);
}
// first byte = F7 + bytes.length
byte[] data = Arrays.copyOf(srcData, srcData.length + 1 + byteNum);
System.arraycopy(data, 0, data, 1 + byteNum, srcData.length);
data[0] = (byte) (OFFSET_LONG_ITEM + byteNum);
System.arraycopy(lenBytes, 0, data, 1, lenBytes.length);
return data;
}
}
public static byte[] encodeList(byte[]... elements) {
int totalLength = 0;
for (int i = 0; i < elements.length; ++i) {
totalLength += elements[i].length;
}
byte[] data;
int copyPos = 0;
if (totalLength < SIZE_THRESHOLD) {
data = new byte[1 + totalLength];
data[0] = (byte) (OFFSET_SHORT_LIST + totalLength);
copyPos = 1;
} else {
// length of length = BX
// prefix = [BX, [length]]
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);
}
// first byte = F7 + bytes.length
data = new byte[1 + lenBytes.length + totalLength];
data[0] = (byte) (OFFSET_LONG_LIST + byteNum);
System.arraycopy(lenBytes, 0, data, 1, lenBytes.length);
copyPos = lenBytes.length + 1;
}
for (int i = 0; i < elements.length; ++i) {
System.arraycopy(elements[i], 0, data, copyPos, elements[i].length);
copyPos += elements[i].length;
}
return data;
}
/*
* Utility function to convert Objects into byte arrays
*/
private static byte[] toBytes(Object input) {
if (input instanceof byte[]) {
return (byte[]) input;
} else if (input instanceof String) {
String inputString = (String) input;
return inputString.getBytes();
} else if(input instanceof Long) {
Long inputLong = (Long) input;
return (inputLong == 0) ? ByteUtil.EMPTY_BYTE_ARRAY : asUnsignedByteArray(BigInteger.valueOf(inputLong));
} else if(input instanceof Integer) {
Integer inputInt = (Integer) input;
return (inputInt == 0) ? ByteUtil.EMPTY_BYTE_ARRAY : asUnsignedByteArray(BigInteger.valueOf(inputInt.intValue()));
} else if(input instanceof BigInteger) {
BigInteger inputBigInt = (BigInteger) input;
return (inputBigInt == BigInteger.ZERO) ? ByteUtil.EMPTY_BYTE_ARRAY : asUnsignedByteArray(inputBigInt);
} else if (input instanceof Value) {
Value val = (Value) input;
return toBytes(val.asObj());
}
throw new RuntimeException("Unsupported type: Only accepting String, Integer and BigInteger for now");
}
}