implement logic to encode and transmit AMBTs;

p25/lc/TSBK.cpp

@@ -334,13 +334,10 @@ bool TSBK::decodeMBT(const data::DataHeader dataHeader, const data::DataBlock* b
 /// Encode a alternate trunking signalling block.
 /// </summary>
 /// <param name="dataHeader"></param>
-/// <param name="blocks"></param>
+/// <param name="pduUserData"></param>
-void TSBK::encodeMBT(data::DataHeader& dataHeader, data::DataBlock* blocks)
+void TSBK::encodeMBT(data::DataHeader& dataHeader, uint8_t* pduUserData)
 {
-    assert(blocks != NULL);
+    assert(pduUserData != NULL);
-
-    uint8_t pduUserData[P25_PDU_UNCONFIRMED_LENGTH_BYTES * 2U];
-    ::memset(pduUserData, 0x00U, P25_PDU_UNCONFIRMED_LENGTH_BYTES * 2U);
 
     dataHeader.setFormat(PDU_FMT_UNCONFIRMED);
     dataHeader.setMFId(m_mfId);
@@ -394,15 +391,8 @@ void TSBK::encodeMBT(data::DataHeader& dataHeader, data::DataBlock* blocks)
     // generate packet CRC-32 and set data blocks
     if (dataHeader.getBlocksToFollow() > 1U) {
         edac::CRC::addCRC32(pduUserData, P25_PDU_UNCONFIRMED_LENGTH_BYTES * dataHeader.getBlocksToFollow());
-
-        uint8_t offs = 0U;
-        for (uint8_t i = 0; i < dataHeader.getBlocksToFollow(); i++) {
-            blocks[i].setData(pduUserData + offs);
-            offs += P25_PDU_UNCONFIRMED_LENGTH_BYTES;
-        }
     } else {
         edac::CRC::addCRC32(pduUserData, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
-        blocks[0U].setData(pduUserData);
     }
 }
 

p25/lc/TSBK.h

@@ -84,7 +84,7 @@ namespace p25
             /// <summary>Decode a alternate trunking signalling block.</summary>
             bool decodeMBT(const data::DataHeader dataHeader, const data::DataBlock* blocks);
             /// <summary>Encode a alternate trunking signalling block.</summary>
-            void encodeMBT(data::DataHeader& dataHeader, data::DataBlock* blocks);
+            void encodeMBT(data::DataHeader& dataHeader, uint8_t* pduUserData);
 
             /// <summary>Decode a trunking signalling block.</summary>
             bool decode(const uint8_t* data, bool rawTSBK = false);

p25/packet/Data.h

@@ -51,6 +51,7 @@ namespace p25
     // ---------------------------------------------------------------------------
     
     class HOST_SW_API Control;
+    namespace packet { class HOST_SW_API Trunk; }
 
     namespace packet
     {
@@ -78,6 +79,7 @@ namespace p25
         private:
             friend class p25::Control;
             Control* m_p25;
+            friend class p25::packet::Trunk;
 
             network::BaseNetwork* m_network;
 

p25/packet/Trunk.cpp

@@ -1666,6 +1666,67 @@ void Trunk::writeRF_TSDU_MBF(bool clearBeforeWrite)
     m_mbfCnt++;
 }
 
+/// <summary>
+/// Helper to write a alternate multi-block trunking PDU packet.
+/// </summary>
+/// <param name="clearBeforeWrite"></param>
+void Trunk::writeRF_PDU_AMBT(bool clearBeforeWrite)
+{
+    if (!m_p25->m_control)
+        return;
+
+    DataHeader rspHeader = DataHeader();
+    uint8_t rspData[P25_PDU_UNCONFIRMED_LENGTH_BYTES * P25_MAX_PDU_COUNT];
+    ::memset(rspData, 0x00U, P25_PDU_UNCONFIRMED_LENGTH_BYTES * P25_MAX_PDU_COUNT);
+
+    // Generate TSBK block
+    m_rfTSBK.setLastBlock(true); // always set last block -- this a Single Block TSDU
+    m_rfTSBK.encodeMBT(rspHeader, rspData);
+
+    if (m_debug) {
+        LogDebug(LOG_RF, P25_PDU_STR " AMBT, lco = $%02X, mfId = $%02X, lastBlock = %u, AIV = %u, EX = %u, srcId = %u, dstId = %u, sysId = $%03X, netId = $%05X",
+            m_rfTSBK.getLCO(), m_rfTSBK.getMFId(), m_rfTSBK.getLastBlock(), m_rfTSBK.getAIV(), m_rfTSBK.getEX(), m_rfTSBK.getSrcId(), m_rfTSBK.getDstId(),
+            m_rfTSBK.getSysId(), m_rfTSBK.getNetId());
+
+        Utils::dump(1U, "!!! *TSDU (AMBT) TSBK Block Data", rspData, P25_PDU_UNCONFIRMED_LENGTH_BYTES * rspHeader.getBlocksToFollow());
+    }
+
+    uint32_t bitLength = ((rspHeader.getBlocksToFollow() + 1U) * P25_PDU_FEC_LENGTH_BITS) + P25_PREAMBLE_LENGTH_BITS;
+    uint32_t offset = P25_PREAMBLE_LENGTH_BITS;
+
+    uint8_t data[bitLength / 8U];
+    ::memset(data, 0x00U, bitLength / 8U);
+    uint8_t block[P25_PDU_FEC_LENGTH_BYTES];
+    ::memset(block, 0x00U, P25_PDU_FEC_LENGTH_BYTES);
+
+    // Generate the PDU header and 1/2 rate Trellis
+    rspHeader.encode(block);
+    Utils::setBitRange(block, data, offset, P25_PDU_FEC_LENGTH_BITS);
+    offset += P25_PDU_FEC_LENGTH_BITS;
+
+    // Generate the PDU data
+    DataBlock rspBlock = DataBlock();
+    uint8_t offs = 0U;
+    for (uint8_t i = 0; i < rspHeader.getBlocksToFollow(); i++) {
+        rspBlock.setFormat(PDU_FMT_UNCONFIRMED);
+        rspBlock.setSerialNo(0U);
+        rspBlock.setData(rspData + offs);
+
+        ::memset(block, 0x00U, P25_PDU_FEC_LENGTH_BYTES);
+        rspBlock.encode(block);
+        Utils::setBitRange(block, data, offset, P25_PDU_FEC_LENGTH_BITS);
+        offset += P25_PDU_FEC_LENGTH_BITS;
+        offs += P25_PDU_UNCONFIRMED_LENGTH_BYTES;
+    }
+
+    if (clearBeforeWrite) {
+        m_p25->m_modem->clearP25Data();
+        m_p25->m_queue.clear();
+    }
+
+    m_p25->m_data->writeRF_PDU(data, bitLength);
+}
+
 /// <summary>
 /// Helper to generate the given control TSBK into the TSDU frame queue.
 /// </summary>

p25/packet/Trunk.h

@@ -178,6 +178,8 @@ namespace p25
             virtual void writeRF_TSDU_SBF(bool noNetwork, bool clearBeforeWrite = false, bool force = false);
             /// <summary>Helper to write a multi-block (3-block) P25 TSDU packet.</summary>
             void writeRF_TSDU_MBF(bool clearBeforeWrite = false);
+            /// <summary>Helper to write a alternate multi-block trunking PDU packet.</summary>
+            void writeRF_PDU_AMBT(bool clearBeforeWrite = false);
 
             /// <summary>Helper to generate the given control TSBK into the TSDU frame queue.</summary>
             void queueRF_TSBK_Ctrl(uint8_t lco);