/// <summary>
/// Apply segmentation over a message possibly splitting it on multiple SMPP PDUs.
/// </summary>
/// <remarks>
/// Method may return the passed pdu (modified as needed) as result in case no splitting is required.
/// </remarks>
/// <param name="pdu">The base pdu to use.</param>
/// <param name="method">The segmentation & reasembly method tu use when splitting the message.</param>
/// <param name="correlationId">The correlation id to set to each message part.</param>
/// <returns>The list of sequence numbers of PDUs sent</returns>
public static IEnumerable<SmppSubmitSm> SplitLongMessage(SmppSubmitSm pdu, SmppSarMethod method, byte correlationId)
{
if (pdu == null) throw new ArgumentNullException("pdu");
var result = new List<SmppSubmitSm>();
var data = pdu.MessagePayload != null ? pdu.MessagePayload : pdu.ShortMessage;
if (data != null && !(data is string || data is byte[]))
throw new ArgumentException("Short Message must be a string or byte array.");
var bytes = data is string ? PduUtil.GetEncodedText(pdu.DataCoding, data as string) : data as byte[];
var maxSegmentLen = GetMaxSegmentLength(pdu.DataCoding, bytes.Length);
// Remove/Reset data from PDU..
pdu.ShortMessage = pdu.MessagePayload = null;
// Remove sequenceNumber.
pdu.SequenceNumber = 0;
// Remove UDH header (if set).
pdu.EsmClass &= ((byte)~NetworkFeatures.UDHI);
// Remove SMPP segmentation properties..
pdu.MoreMessagesToSend = null;
pdu.NumberOfMessages = null;
pdu.SarTotalSegments = null;
pdu.SarMsgRefNumber = null;
// Sending as payload means avoiding all the data splitting logic.. (which is great ;))
if (method == SmppSarMethod.SendAsPayload)
{
pdu.MessagePayload = data;
return new[] { pdu };
}
// Else.. let's do segmentation and the other crappy stuff..
var udhref = method == SmppSarMethod.UserDataHeader ? new Nullable<byte>(correlationId) : null;
var segments = SplitMessage(bytes, maxSegmentLen, udhref);
var totalSegments = segments.Count();
var segno = 0;
// If just one segment, send it w/o SAR parameters..
if (totalSegments < 2)
{
pdu.ShortMessage = data;
return new[] { pdu };
}
// Ok, se we need segmentation, let's go ahead an use input PDU as template.
var template = pdu.GetEncodedPdu();
// Well save results here..
var results = new List<SmppSubmitSm>();
foreach (var segment in segments)
{
var packet = new SmppSubmitSm(template);
segno++; // Increase sequence number.
packet.SequenceNumber = 0; // Remove sequenceNumber.
packet.ShortMessage = segment; // Set current segment bytes as short message..
switch (method)
{
case SmppSarMethod.UserDataHeader:
packet.EsmClass |= (byte)NetworkFeatures.UDHI; // Set UDH flag..
break;
case SmppSarMethod.UseSmppSegmentation:
packet.EsmClass &= ((byte)~NetworkFeatures.UDHI); // Remove UDH header (if set).
// Fill-in SMPP segmentation fields..
packet.MoreMessagesToSend = segno != totalSegments;
packet.NumberOfMessages = (byte)totalSegments;
packet.SarTotalSegments = (byte)totalSegments;
packet.SarMsgRefNumber = correlationId;
packet.SarSegmentSeqnum = (byte)segno;
break;
}
result.Add(packet);
}
return result;
}
