/// <summary>
/// Search a specific TLC in a buffer
/// </summary>
/// <param name="tag">The TLV tag to find</param>
/// <param name="buffer">The buffer to loolk the TLV inside</param>
/// <returns>A CTLV object</returns>
public static CTLV SearchTLV(string tag, byte[] buffer)
{
CTLV tlv = null;
int offset = 0;
bool fFound = false, fOK = true;
do
{
int start = offset;
try
{
// extract the current PI
tlv = ExtractTLV(buffer, start, out offset);
}
catch (Exception ex)
{
CLog.AddException(MethodBase.GetCurrentMethod().Name, ex);
fOK = false;
tlv = null;
}
if (null != tlv)
{
// a PI was found, is it the one we're looking for ?
fFound = tlv.T == tag;
if (!fFound)
{
tlv = null;
}
}
}while (!fFound && buffer.Length > offset && fOK);
return(tlv);
}
/// <summary>
/// Remove a TLV record from the field
/// </summary>
/// <param name="tlv">The fully formatted TLV record</param>
/// <returns></returns>
public bool RemoveTLV(CTLV tlv)
{
try
{
_tlv.Remove(tlv.T);
return(true);
}
catch (Exception ex)
{
CLog.AddException(MethodBase.GetCurrentMethod().Name, ex, "TLV: " + tlv.ToString());
return(false);
}
}
/// <summary>
/// Get the content of a TLV value part
/// </summary>
/// <param name="buffer">Buffer to extract the TLV from.
/// This buffer must contain ONLY TLV fields as it will rely on the available siez to stop searching TLVs.
/// If the buffer contains something else than TLV fields, the function won't notice it.</param>
/// <param name="start">Start position inside the buffer to retrieve the TLV</param>
/// <param name="offset">Offset after the TLV</param>
public static CTLV ExtractTLV(byte[] buffer, int start, out int offset)
{
CTLV tlv = null;
offset = start;
if (buffer.Length - offset > CTLV.TLV_SIZE_T + CTLV.TLV_SIZE_L + 1)
{
byte[] rawdata;
int mystart = start;
CEncoderAN encoderAN = new CEncoderAN();
// enough room for T+L+V (1 byte at least)
//get T
string T = (encoderAN.Decode(buffer, offset, CTLV.TLV_SIZE_T, CTLV.TLV_SIZE_T, out offset, out rawdata)).ToString();
// get L
short L = (short)CMisc.StrToLong(encoderAN.ToString(encoderAN.Decode(buffer, offset, CTLV.TLV_SIZE_L, CTLV.TLV_SIZE_L, out offset, out rawdata)));
if (0 != tlv.L)
{
if (buffer.Length - offset >= L)
{
byte[] V = new byte[L];
// get V
Buffer.BlockCopy(buffer, offset, V, 0, L);
offset += tlv.L;
tlv = new CTLV(T, L, FieldType.NONE);
tlv.SetV(V);
return(tlv);
}
else
{
throw new CInvalidDataSizeException("TAG " + T, L, buffer.Length - offset);
}
}
else
{
throw new CInvalidValueException("TAG " + T, L.ToString());
}
}
else
{
throw new CInvalidDataSizeException("TLV", CTLV.TLV_SIZE_T + CTLV.TLV_SIZE_L + 1, buffer.Length - offset);
}
}