add enum for predefined symbols, enhance getStr()

src/ebusd/mainloop.cpp

@@ -108,7 +108,7 @@ MainLoop::MainLoop(const struct options& opt, BusHandler* busHandler,
   : Thread(), m_busHandler(busHandler), m_protocol(busHandler->getProtocol()), m_reconnectCount(0),
     m_userList(opt.accessLevel), m_messages(messages),
     m_scanHelper(scanHelper), m_address(opt.address), m_scanConfig(opt.scanConfig),
-    m_initialScan(opt.readOnly ? ESC : opt.initialScan), m_scanRetries(opt.scanRetries),
+    m_initialScan(opt.readOnly ? (symbol_t)ESC : opt.initialScan), m_scanRetries(opt.scanRetries),
     m_scanStatus(SCAN_STATUS_NONE), m_polling(opt.pollInterval > 0), m_enableHex(opt.enableHex),
     m_shutdown(false), m_runUpdateCheck(opt.updateCheck), m_httpClient(), m_requestQueue(requestQueue) {
   if (opt.aclFile[0]) {
@@ -676,7 +676,7 @@ result_t MainLoop::executeRead(const vector<string>& args, const string& levels,
       if (dest) {
         dstAddress = address;
       } else {
-        srcAddress = address == m_address ? SYN : address;
+        srcAddress = address == m_address ? (symbol_t)SYN : address;
       }
     } else if (args[argPos] == "-p") {
       argPos++;
@@ -933,7 +933,7 @@ result_t MainLoop::executeWrite(const vector<string>& args, const string levels,
       if (dest) {
         dstAddress = address;
       } else {
-        srcAddress = address == m_address ? SYN : address;
+        srcAddress = address == m_address ? (symbol_t)SYN : address;
       }
     } else if (args[argPos] == "-c") {
       argPos++;
@@ -1110,7 +1110,7 @@ result_t MainLoop::parseHexAndSend(const vector<string>& args, size_t& argPos, b
       if (ret != RESULT_OK || !isValidAddress(address, false) || !isMaster(address)) {
         return RESULT_ERR_INVALID_ADDR;
       }
-      srcAddress = address == m_address ? SYN : address;
+      srcAddress = address == m_address ? (symbol_t)SYN : address;
     } else if (args[argPos] == "-n") {
       autoLength = true;
     } else {

src/lib/ebus/message.cpp

@@ -200,7 +200,7 @@ uint64_t Message::createKey(const MasterSymbolString& master, size_t maxIdLength
   }
   uint64_t key = (uint64_t)idLength << (8 * 7 + 5);
   key |= (uint64_t)getMasterNumber(master[0]) << (8 * 7);  // QQ address for passive message
-  key |= (uint64_t)(anyDestination ? SYN : master[1]) << (8 * 6);  // ZZ address
+  key |= (uint64_t)(anyDestination ? (symbol_t)SYN : master[1]) << (8 * 6);  // ZZ address
   key |= (uint64_t)master[2] << (8 * 5);  // PB
   key |= (uint64_t)master[3] << (8 * 4);  // SB
   int exp = 3;

src/lib/ebus/symbol.cpp

@@ -145,14 +145,21 @@ result_t SymbolString::parseHexEscaped(const string& str) {
   return inEscape ? RESULT_ERR_ESC : RESULT_OK;
 }
 
-const string SymbolString::getStr(size_t skipFirstSymbols) const {
+const string SymbolString::getStr(size_t skipFirstSymbols, size_t maxLength, bool withLength) const {
   ostringstream sstr;
+  if (maxLength == 0) {
+    maxLength = m_data.size();
+  }
+  size_t lengthOffset = withLength ? 254 : (m_isMaster ? 4 : 0);
   for (size_t i = 0; i < m_data.size(); i++) {
     if (skipFirstSymbols > 0) {
       skipFirstSymbols--;
-    } else {
+    } else if (i != lengthOffset) {
       sstr << nouppercase << setw(2) << hex
           << setfill('0') << static_cast<unsigned>(m_data[i]);
+          if (--maxLength == 0) {
+            break;
+          }
     }
   }
   return sstr.str();

src/lib/ebus/symbol.h

@@ -72,20 +72,21 @@ using std::ostringstream;
 /** the base type for symbols sent to/from the eBUS. */
 typedef unsigned char symbol_t;
 
-/** escape symbol, either followed by 0x00 for the value 0xA9, or 0x01 for the value 0xAA. */
-#define ESC ((symbol_t)0xA9)
-
-/** synchronization symbol. */
-#define SYN ((symbol_t)0xAA)
-
-/** positive acknowledge symbol. */
-#define ACK ((symbol_t)0x00)
-
-/** negative acknowledge symbol. */
-#define NAK ((symbol_t)0xFF)
-
-/** the broadcast destination address. */
-#define BROADCAST ((symbol_t)0xFE)
+/**
+ * List of predefined eBUS symbols.
+ */
+enum PredefinedSymbol : symbol_t {
+  /** escape symbol, either followed by 0x00 for the value 0xA9, or 0x01 for the value 0xAA. */
+  ESC = 0xA9,
+  /** synchronization symbol. */
+  SYN = 0xAA,
+  /** positive acknowledge symbol. */
+  ACK = 0x00,
+  /** negative acknowledge symbol. */
+  NAK = 0xFF,
+  /** the broadcast destination address. */
+  BROADCAST = 0xFE,
+};
 
 /**
  * Parse an unsigned int value.
@@ -156,9 +157,11 @@ class SymbolString {
   /**
    * Return the symbols as hex string.
    * @param skipFirstSymbols the number of first symbols to skip.
+   * @param maxLength the maximum number of symbols to include (or 0 for all).
+   * @param withLength whether to include the NN length field.
    * @return the symbols as hex string.
    */
-  const string getStr(size_t skipFirstSymbols = 0) const;
+  const string getStr(size_t skipFirstSymbols = 0, size_t maxLength = 0, bool withLength = true) const;
 
   /**
    * Dump the data in JSON format to the output.