Beispiel #1
0
        private static void ParseTlv(byte[] rawTlv, ICollection <Tlv> result)
        {
            for (int i = 0, start = 0; i < rawTlv.Length; start = i)
            {
                // 0x00 and 0xFF can be used as padding before, between, and after tags
                if (rawTlv[i] == 0x00)
                {
                    i++;
                    continue;
                }

                // bit6 being 1 indicates that the tag is 'constructed' (contains more tags within it)
                bool constructedTlv = (rawTlv[i] & 0x20) != 0;

                // bit1 through 5 being 1 indicates that the tag is more than one byte long
                // recognize this and keep looking until we find the last byte of the tag, indicated by bit8 being 0
                bool multiByteTag = (rawTlv[i] & 0x1F) == 0x1F;
                while (multiByteTag && (rawTlv[++i] & 0x80) != 0)
                {
                    ;
                }

                // i is on the last byte of the tag, so move it forward one and
                // retreve the tag value from the raw tlv
                i++;
                int tag = GetInt(rawTlv, start, i - start);

                // bit8 being 1 indicates that the length is multiple bytes long
                bool multiByteLength = (rawTlv[i] & 0x80) != 0;

                int length = multiByteLength ? GetInt(rawTlv, i + 1, rawTlv[i] & 0x1F) : rawTlv[i];
                i = multiByteLength ? i + (rawTlv[i] & 0x1F) + 1 : i + 1;

                // i is on the last byte of the length, so move it forward by the length we found
                i += length;

                // now that we know the start position and length of the data, retrieve it
                // then create the Tlv object and add it to the list
                byte[] rawData = new byte[i - start];
                Array.Copy(rawTlv, start, rawData, 0, i - start);
                var tlv = new Tlv(tag, length, rawData.Length - length, rawData);
                result.Add(tlv);

                // if this was a constructed tag, parse its value into individual Tlv children as well
                if (constructedTlv)
                {
                    ParseTlv(tlv.Value, tlv.Children);
                }
            }
        }
Beispiel #2
0
        private static void ParseTlv(byte[] rawTlv, ICollection<Tlv> result)
        {
            for(int i = 0, start = 0; i < rawTlv.Length; start = i)
            {
                // parse Tag
                bool constructedTlv = (rawTlv[i] & 0x20) != 0;
                bool moreBytes = (rawTlv[i] & 0x1F) == 0x1F;
                while(moreBytes && (rawTlv[++i] & 0x80) != 0) ;
                i++;

                int tag = GetInt(rawTlv, start, i - start);

                // parse Length
                bool multiByteLength = (rawTlv[i] & 0x80) != 0;

                int length = multiByteLength ? GetInt(rawTlv, i + 1, rawTlv[i] & 0x1F) : rawTlv[i];
                i = multiByteLength ? i + (rawTlv[i] & 0x1F) + 1 : i + 1;

                i += length;

                byte[] rawData = new byte[i - start];
                Array.Copy(rawTlv, start, rawData, 0, i - start);
                var tlv = new Tlv(tag, length, rawData.Length - length, rawData);
                result.Add(tlv);

                if(constructedTlv)
                {
                    ParseTlv(tlv.Value, tlv.Children);
                }
            }
        }