private static void checkSequenceError(byte[] bytes, string start, string expected)
{
if (BinaryAscii.hexFromBinary(bytes).Substring(0, start.Length) != start)
{
throw new ArgumentException(
"wanted sequence " +
expected.Substring(0, 2) +
", got " +
extractFirstInt(bytes).ToString("X")
);
}
}
public static Tuple <BigInteger, byte[]> removeInteger(byte[] bytes)
{
checkSequenceError(bytes, hexB, "02");
Tuple <int, int> readLengthResult = readLength(Bytes.sliceByteArray(bytes, 1));
int length = readLengthResult.Item1;
int lengthLen = readLengthResult.Item2;
byte[] numberBytes = Bytes.sliceByteArray(bytes, 1 + lengthLen, length);
byte[] rest = Bytes.sliceByteArray(bytes, 1 + lengthLen + length);
int nBytes = numberBytes[0];
if (nBytes >= hex128)
{
throw new ArgumentException("first byte of integer must be < 128");
}
return(new Tuple <BigInteger, byte[]> (
BinaryAscii.numberFromHex(BinaryAscii.hexFromBinary(numberBytes)),
rest
));
}
private static Tuple <int, int> readLength(byte[] bytes)
{
int num = extractFirstInt(bytes);
if ((num & hex128) == 0)
{
return(new Tuple <int, int>(num & hex127, 1));
}
int lengthLen = num & hex127;
if (lengthLen > bytes.Length - 1)
{
throw new ArgumentException("ran out of length bytes");
}
return(new Tuple <int, int>(
int.Parse(
BinaryAscii.hexFromBinary(Bytes.sliceByteArray(bytes, 1, lengthLen)),
System.Globalization.NumberStyles.HexNumber
),
1 + lengthLen
));
}
