public static IRLPElement DecodeFirstElement(byte[] msgData, int startPos)
{
var rlpCollection = new RLPCollection();
Decode(msgData, 0, startPos, startPos + 1, 1, rlpCollection);
return(rlpCollection[0]);
}
private static int ProcessListLessThan55Bytes(byte[] msgData, int level, int levelToIndex,
RLPCollection rlpCollection, int currentPosition)
{
var length = msgData[currentPosition] - OFFSET_SHORT_LIST;
var rlpDataLength = length + 1;
var rlpData = new byte[length + 1];
Array.Copy(msgData, currentPosition, rlpData, 0, rlpDataLength);
var newLevelCollection = new RLPCollection {
RLPData = rlpData
};
if (length > 0)
{
Decode(msgData, level + 1, currentPosition + 1, currentPosition + rlpDataLength,
levelToIndex,
newLevelCollection);
}
rlpCollection.Add(newLevelCollection);
currentPosition += rlpDataLength;
return(currentPosition);
}
/// <summary>
/// Parses byte[] message into RLP items
/// </summary>
/// <param name="msgData">raw RLP data </param>
/// <returns> RlpList: outcome of recursive RLP structure </returns>
public static RLPCollection Decode(byte[] msgData)
{
var rlpCollection = new RLPCollection();
Decode(msgData, 0, 0, msgData.Length, 1, rlpCollection);
return(rlpCollection);
}
private static int ProcessNullItem(RLPCollection rlpCollection, int currentPosition)
{
var item = EMPTY_BYTE_ARRAY;
var rlpItem = new RLPItem(item);
rlpCollection.Add(rlpItem);
currentPosition += 1;
return currentPosition;
}
private static int ProcessSingleByteItem(byte[] msgData, RLPCollection rlpCollection, int currentPosition)
{
byte[] item = { msgData[currentPosition] };
var rlpItem = new RLPItem(item);
rlpCollection.Add(rlpItem);
currentPosition += 1;
return currentPosition;
}
private static int ProcessItemLessThan55Bytes(byte[] msgData, RLPCollection rlpCollection, int currentPosition)
{
var length = (byte)(msgData[currentPosition] - OFFSET_SHORT_ITEM);
var item = new byte[length];
Array.Copy(msgData, currentPosition + 1, item, 0, length);
var rlpPrefix = new byte[2];
Array.Copy(msgData, currentPosition, rlpPrefix, 0, 2);
var rlpItem = new RLPItem(item);
rlpCollection.Add(rlpItem);
currentPosition += 1 + length;
return currentPosition;
}
/// \\
/// Decodes a message from a starting point to an end point
/// \\
public static void Decode(byte[] msgData, int level, int startPosition,
int endPosition, int levelToIndex, RLPCollection rlpCollection)
{
if (msgData == null || msgData.Length == 0)
return;
var currentData = new byte[endPosition - startPosition];
Array.Copy(msgData, startPosition, currentData, 0, currentData.Length);
try
{
var currentPosition = startPosition;
while (currentPosition \ {
if (IsListBiggerThan55Bytes(msgData, currentPosition))
{
currentPosition = ProcessListBiggerThan55Bytes(msgData, level, levelToIndex, rlpCollection,
currentPosition);
continue;
}
if (IsListLessThan55Bytes(msgData, currentPosition))
{
currentPosition = ProcessListLessThan55Bytes(msgData, level, levelToIndex, rlpCollection,
currentPosition);
continue;
}
if (IsItemBiggerThan55Bytes(msgData, currentPosition))
{
currentPosition = ProcessItemBiggerThan55Bytes(msgData, rlpCollection, currentPosition);
continue;
}
if (IsItemLessThan55Bytes(msgData, currentPosition))
{
currentPosition = ProcessItemLessThan55Bytes(msgData, rlpCollection, currentPosition);
continue;
}
if (IsNullItem(msgData, currentPosition))
{
currentPosition = ProcessNullItem(rlpCollection, currentPosition);
continue;
}
if (IsSigleByteItem(msgData, currentPosition))
currentPosition = ProcessSingleByteItem(msgData, rlpCollection, currentPosition);
}
}
catch (Exception ex)
{
throw new Exception(
"Invalid RLP " + currentData.ToHex(), ex);
}
}
private static int ProcessListBiggerThan55Bytes(byte[] msgData, int level, int levelToIndex,
RLPCollection rlpCollection, int currentPosition)
{
var lengthOfLength = (byte)(msgData[currentPosition] - OFFSET_LONG_LIST);
var length = CalculateLength(lengthOfLength, msgData, currentPosition);
var rlpDataLength = lengthOfLength + length + 1;
var rlpData = new byte[rlpDataLength];
Array.Copy(msgData, currentPosition, rlpData, 0, rlpDataLength);
var newLevelCollection = new RLPCollection { RLPData = rlpData };
Decode(msgData, level + 1, currentPosition + lengthOfLength + 1,
currentPosition + rlpDataLength, levelToIndex,
newLevelCollection);
rlpCollection.Add(newLevelCollection);
currentPosition += rlpDataLength;
return currentPosition;
}
private static int ProcessItemBiggerThan55Bytes(byte[] msgData, RLPCollection rlpCollection,
int currentPosition)
{
var lengthOfLength = (byte)(msgData[currentPosition] - OFFSET_LONG_ITEM);
var length = CalculateLength(lengthOfLength, msgData, currentPosition);
// now we can parse an item for data[1]..data[length]
var item = new byte[length];
Array.Copy(msgData, currentPosition + lengthOfLength + 1, item,
0, length);
var rlpPrefix = new byte[lengthOfLength + 1];
Array.Copy(msgData, currentPosition, rlpPrefix, 0,
lengthOfLength + 1);
var rlpItem = new RLPItem(item);
rlpCollection.Add(rlpItem);
currentPosition += lengthOfLength + length + 1;
return currentPosition;
}
