/**
* Parse wire byte[] message into RLP elements.
*
* @param rlpEncoded - RLP encoded byte-array
* @return recursive RLP structure
*/
public static RlpList Decode(byte[] rlpEncoded)
{
var rlpList = new RlpList();
Traverse(rlpEncoded, 0, rlpEncoded.Length, rlpList);
return(rlpList);
}
private static byte[] EncodeList(RlpList values)
{
if (values == null || values.Count < 1)
{
return(Encode(new byte[] { }, OFFSET_SHORT_LIST));
}
byte[] result = new byte[0];
foreach (IRlpType entry in values)
{
result = result.Concat(Encode(entry));
}
return(Encode(result, OFFSET_SHORT_LIST));
}
private static void Traverse(byte[] data, int startPos, int endPos, RlpList rlpList)
{
try
{
if (data == null || data.Length == 0)
{
return;
}
while (startPos < endPos)
{
var prefix = data[startPos] & 0xff;
if (prefix < OFFSET_SHORT_STRING)
{
// 1. the data is a string if the range of the
// first byte(i.e. prefix) is [0x00, 0x7f],
// and the string is the first byte itself exactly;
byte[] rlpData = { (byte)prefix };
rlpList.Add(RlpString.Create(rlpData));
startPos += 1;
}
else if (prefix == OFFSET_SHORT_STRING)
{
// null
rlpList.Add(RlpString.Create(new byte[0]));
startPos += 1;
}
else if (prefix > OFFSET_SHORT_STRING && prefix <= OFFSET_LONG_STRING)
{
// 2. the data is a string if the range of the
// first byte is [0x80, 0xb7], and the string
// which length is equal to the first byte minus 0x80
// follows the first byte;
byte strLen = (byte)(prefix - OFFSET_SHORT_STRING);
byte[] rlpData = new byte[strLen];
Unsafe.CopyBlock(ref rlpData[0], ref data[startPos + 1], (uint)strLen);
// Array.Copy(data, startPos + 1, rlpData, 0, strLen);
rlpList.Add(RlpString.Create(rlpData));
startPos += 1 + strLen;
}
else if (prefix > OFFSET_LONG_STRING && prefix < OFFSET_SHORT_LIST)
{
// 3. the data is a string if the range of the
// first byte is [0xb8, 0xbf], and the length of the
// string which length in bytes is equal to the
// first byte minus 0xb7 follows the first byte,
// and the string follows the length of the string;
byte lenOfStrLen = (byte)(prefix - OFFSET_LONG_STRING);
int strLen = CalcLength(lenOfStrLen, data, startPos);
// now we can parse an item for data[1]..data[length]
byte[] rlpData = new byte[strLen];
Unsafe.CopyBlock(ref rlpData[0], ref data[startPos + lenOfStrLen + 1], (uint)strLen);
// Array.Copy(data, startPos + lenOfStrLen + 1, rlpData, 0, strLen);
rlpList.Add(RlpString.Create(rlpData));
startPos += lenOfStrLen + strLen + 1;
}
else if (prefix >= OFFSET_SHORT_LIST && prefix <= OFFSET_LONG_LIST)
{
// 4. the data is a list if the range of the
// first byte is [0xc0, 0xf7], and the concatenation of
// the RLP encodings of all items of the list which the
// total payload is equal to the first byte minus 0xc0 follows the first byte;
byte listLen = (byte)(prefix - OFFSET_SHORT_LIST);
RlpList newLevelList = new RlpList();
Traverse(data, startPos + 1, startPos + listLen + 1, newLevelList);
rlpList.Add(newLevelList);
startPos += 1 + listLen;
}
else if (prefix > OFFSET_LONG_LIST)
{
// 5. the data is a list if the range of the
// first byte is [0xf8, 0xff], and the total payload of the
// list which length is equal to the
// first byte minus 0xf7 follows the first byte,
// and the concatenation of the RLP encodings of all items of
// the list follows the total payload of the list;
byte lenOfListLen = (byte)(prefix - OFFSET_LONG_LIST);
int listLen = CalcLength(lenOfListLen, data, startPos);
RlpList newLevelList = new RlpList();
Traverse(data, startPos + lenOfListLen + 1,
startPos + lenOfListLen + listLen + 1, newLevelList);
rlpList.Add(newLevelList);
startPos += lenOfListLen + listLen + 1;
}
}
}
catch (Exception e)
{
throw new FormatException("RLP wrong encoding", e);
}
}
