Split a byte array at a delimiter

Question

I\'m having a bit of an issue and, the other questions here didn\'t help me much.

I am a security student and I am trying to write a crypter for a project. For those

Answer 1

I know I'm really, really late to the party, but... You can of course modify this to return a List easily if preferred. I left comments/writelines in case it would be helpful... This may not be the most optimal/optimized code but works well for my specific use case and I thought I would share.

    public static byte[][] SplitBytesByDelimiter(byte[] data, byte delimiter)
    {
        if (data == null) throw new ArgumentNullException(nameof(data));
        if (data.Length < 1) return null;

        List retList = new List();

        int start = 0;
        int pos = 0;
        byte[] remainder = null; // in case data found at end without terminating delimiter

        while (true)
        {
            // Console.WriteLine("pos " + pos + " start " + start);
            if (pos >= data.Length) break;

            if (data[pos] == delimiter)
            {
                // Console.WriteLine("delimiter found at pos " + pos + " start " + start);

                // separator found
                if (pos == start)
                {
                    // Console.WriteLine("first char is delimiter, skipping");
                    // skip if first character is delimiter
                    pos++;
                    start++;
                    if (pos >= data.Length)
                    {
                        // last character is a delimiter, yay!
                        remainder = null;
                        break;
                    }
                    else
                    {
                        // remainder exists
                        remainder = new byte[data.Length - start];
                        Buffer.BlockCopy(data, start, remainder, 0, (data.Length - start));
                        continue;
                    }
                }
                else
                {
                    // Console.WriteLine("creating new byte[] at pos " + pos + " start " + start);
                    byte[] ba = new byte[(pos - start)];
                    Buffer.BlockCopy(data, start, ba, 0, (pos - start));
                    retList.Add(ba);

                    start = pos + 1;
                    pos = start;

                    if (pos >= data.Length)
                    {
                        // last character is a delimiter, yay!
                        remainder = null;
                        break;
                    }
                    else
                    {
                        // remainder exists
                        remainder = new byte[data.Length - start];
                        Buffer.BlockCopy(data, start, remainder, 0, (data.Length - start));
                    }
                }
            }
            else
            {
                // payload character, continue;
                pos++;
            }
        }

        if (remainder != null)
        {
            // Console.WriteLine("adding remainder");
            retList.Add(remainder);
        }

        return retList.ToArray();
    }