Add POCSAG processing and display code.

POCSAGControl.cpp

@@ -22,15 +22,24 @@
 
 // #define	DUMP_POCSAG
 
-const unsigned char BIT_MASK_TABLE[] = { 0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U };
+const unsigned char ASCII_EOT = 0x04U;
 
-#define WRITE_BIT1(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE[(i)&7])
-#define READ_BIT1(p,i)    (p[(i)>>3] & BIT_MASK_TABLE[(i)&7])
+const unsigned char BIT_MASK_TABLE8[] = { 0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U };
+
+#define WRITE_BIT8(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE8[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE8[(i)&7])
+#define READ_BIT8(p,i)    (p[(i)>>3] & BIT_MASK_TABLE8[(i)&7])
 
 CPOCSAGControl::CPOCSAGControl(CPOCSAGNetwork* network, CDisplay* display) :
 m_network(network),
 m_display(display),
 m_queue(5000U, "POCSAG Control"),
+m_frames(0U),
+m_count(0U),
+m_output(),
+m_buffer(),
+m_ric(0U),
+m_text(),
+m_state(PS_NONE),
 m_fp(NULL)
 {
 	assert(display != NULL);
@@ -38,6 +47,8 @@ m_fp(NULL)
 
 CPOCSAGControl::~CPOCSAGControl()
 {
+	m_output.clear();
+	m_buffer.clear();
 }
 
 unsigned int CPOCSAGControl::readModem(unsigned char* data)
@@ -55,20 +66,203 @@ unsigned int CPOCSAGControl::readModem(unsigned char* data)
 	return len;
 }
 
-void CPOCSAGControl::writeNetwork()
+bool CPOCSAGControl::processData()
 {
-	unsigned char netData[40U];
-	unsigned int length = m_network->read(netData);
-	if (length == 0U)
-		return;
+	assert(m_network != NULL);
 
+	unsigned char data[40U];
+	unsigned int length = m_network->read(data);
+	if (length == 0U)
+		return false;
+
+	m_ric = 0U;
+	m_ric |= (data[0U] << 16) & 0x00FF0000U;
+	m_ric |= (data[1U] << 8) & 0x0000FF00U;
+	m_ric |= (data[2U] << 0) & 0x000000FFU;
+
+	m_text = std::string((char*)(data + 3U), length - 3U);
+
+	m_buffer.clear();
+	addAddress();
+	packASCII();
+
+	// Ensure data is an even number of words
+	if ((m_buffer.size() % 2U) == 1U)
+		m_buffer.push_back(POCSAG_IDLE_WORD);
+
+	return true;
 }
 
 void CPOCSAGControl::clock(unsigned int ms)
 {
-	if (m_network != NULL)
-		writeNetwork();
+	if (m_state == PS_NONE) {
+		bool ret = processData();
+		if (!ret)
+			return;
 
+		m_display->writePOCSAG(m_ric, m_text);
+		m_state  = PS_WAITING;
+		m_frames = 0U;
+		m_count  = 1U;
+	}
+
+	m_output.clear();
+	m_output.push_back(POCSAG_SYNC_WORD);
+
+	for (unsigned int i = 0U; i < POCSAG_FRAME_ADDRESSES; i++) {
+		if (m_state == PS_WAITING) {
+			if (i == (m_ric % POCSAG_FRAME_ADDRESSES)) {
+				uint32_t w1 = m_buffer.front();
+				m_buffer.pop_front();
+				uint32_t w2 = m_buffer.front();
+				m_buffer.pop_front();
+
+				m_output.push_back(w1);
+				m_output.push_back(w2);
+
+				m_state = PS_SENDING;
+			} else {
+				m_output.push_back(POCSAG_IDLE_WORD);
+				m_output.push_back(POCSAG_IDLE_WORD);
+			}
+		} else if (m_state == PS_SENDING) {
+			uint32_t w1 = m_buffer.front();
+			m_buffer.pop_front();
+			uint32_t w2 = m_buffer.front();
+			m_buffer.pop_front();
+
+			m_output.push_back(w1);
+			m_output.push_back(w2);
+
+			if (m_buffer.empty()) {
+				bool ret = processData();
+				if (ret) {
+					m_display->writePOCSAG(m_ric, m_text);
+					m_state = PS_WAITING;
+					m_count++;
+				} else {
+					m_state = PS_ENDING;
+				}
+			}
+		} else {		// PS_ENDING
+			m_output.push_back(POCSAG_IDLE_WORD);
+			m_output.push_back(POCSAG_IDLE_WORD);
+		}
+	}
+
+	writeQueue();
+	m_frames++;
+
+	if (m_state == PS_ENDING) {
+		LogMessage("POCSAG, transmitted %u frames of data from %u messages", m_frames, m_count);
+		m_display->clearPOCSAG();
+		m_state = PS_NONE;
+	}
+}
+
+void CPOCSAGControl::addAddress()
+{
+	uint32_t word = 0x00001800U;
+
+	word |= (m_ric / POCSAG_FRAME_ADDRESSES) << 13;
+
+	addBCHAndParity(word);
+
+	m_buffer.push_back(word);
+}
+
+void CPOCSAGControl::packASCII()
+{
+	uint32_t word = 0x80000000U;
+
+	unsigned int n = 30U;
+	for (std::string::const_iterator it = m_text.cbegin(); it != m_text.cend(); ++it) {
+		unsigned char MASK = 0x40U;
+		for (unsigned int j = 0U; j < 7U; j++, MASK >>= 1) {
+			bool b = (*it & MASK) == MASK;
+			if (b)
+				word |= (0x01U << n);
+			n--;
+
+			if (n == 10U) {
+				addBCHAndParity(word);
+				m_buffer.push_back(word);
+				word = 0x80000000U;
+				n = 30U;
+			}
+		}
+	}
+
+	// Add at least one EOT to the message
+	do {
+		unsigned char MASK = 0x70U;
+		for (unsigned int j = 0U; j < 7U; j++, MASK >>= 1) {
+			bool b = (ASCII_EOT & MASK) == MASK;
+			if (b)
+				word |= (0x01U << n);
+			n--;
+
+			if (n == 10U) {
+				addBCHAndParity(word);
+				m_buffer.push_back(word);
+				word = 0x80000000U;
+				n = 30U;
+			}
+		}
+	} while (n != 30U);
+}
+
+void CPOCSAGControl::addBCHAndParity(uint32_t& word) const
+{
+	uint32_t temp = word;
+
+	for (unsigned int i = 0U; i < 21U; i++, temp <<= 1) {
+		if (temp & 0x80000000U)
+			temp ^= 0xED200000U;
+	}
+
+	word |= (temp >> 21);
+
+	temp = word;
+
+	unsigned int parity = 0U;
+	for (unsigned int i = 0U; i < 32U; i++, temp <<= 1) {
+		if (temp & 0x80000000U)
+			parity++;
+	}
+
+	if ((parity % 2U) == 1U)
+		word |= 0x00000001U;
+}
+
+void CPOCSAGControl::writeQueue()
+{
+	// Convert 32-bit words to bytes
+	unsigned int n = 0U;
+	unsigned char data[POCSAG_FRAME_LENGTH_BYTES];
+	for (unsigned int i = 0U; i < POCSAG_FRAME_LENGTH_WORDS; i++) {
+		uint32_t w = m_output.front();
+		m_output.pop_front();
+
+		for (unsigned int j = 0U; j < 31U; j++, w <<= 1) {
+			bool b = (w & 0x80000000U) == 0x80000000U;
+			WRITE_BIT8(data, n, b);
+			n++;
+		}
+	}
+
+	unsigned char len = POCSAG_FRAME_LENGTH_BYTES;
+
+	CUtils::dump(1U, "Data to MMDVM", data, len);
+
+	unsigned int space = m_queue.freeSpace();
+	if (space < (len + 1U)) {
+		LogError("POCSAG, overflow in the POCSAG RF queue");
+		return;
+	}
+
+	m_queue.addData(&len, 1U);
+	m_queue.addData(data, len);
 }
 
 bool CPOCSAGControl::openFile()
@@ -88,7 +282,7 @@ bool CPOCSAGControl::openFile()
 	if (m_fp == NULL)
 		return false;
 
-	::fwrite("POCSAG", 1U, 3U, m_fp);
+	::fwrite("POCSAG", 1U, 6U, m_fp);
 
 	return true;
 }