added option to read only a single field

src/ebusd/baseloop.cpp

@@ -253,7 +253,7 @@ string BaseLoop::decodeMessage(const string& data)
 			argPos++;
 		}
 		if (args.size() < argPos + 1 || args.size() > argPos + 3) {
-			result << "usage: 'read [-f] [-v] [class] cmd'"; // TODO or 'read [-f] class cmd sub'";
+			result << "usage: 'read [-v] [-f] [-m seconds] [class] cmd' or 'read [-v] [-f] [-m seconds] class cmd sub'";
 			break;
 		}
 
@@ -309,7 +309,9 @@ string BaseLoop::decodeMessage(const string& data)
 			ret = m_busHandler->sendAndWait(master, slave);
 
 			if (ret == RESULT_OK) {
-				// TODO reduce to requested variable only
+				if (args.size() == argPos + 3)
+					ret = message->decode(pt_slaveData, slave, result, false, verbose, args[argPos + 2].c_str());
+				else
 					ret = message->decode(pt_slaveData, slave, result, false, verbose); // decode data
 			}
 			if (ret != RESULT_OK) {
@@ -501,12 +503,11 @@ string BaseLoop::decodeMessage(const string& data)
 	}
 	case ct_help:
 		result << "commands:" << endl
-		       << " read      - read ebus values            'read [-f] [-v] [class] cmd'" << endl
+		       << " read      - read ebus values            'read [-v] [-f] [-m seconds] [class] cmd' or 'read [-v] [-f] [-m seconds] class cmd sub'" << endl
-		       << " write     - write ebus values           'write class cmd value[;value]*'" << endl
+		       << " write     - write ebus values           'write class cmd value[;value]*' or 'write -h ZZPBSBNNDx'" << endl
-		       << " hex       - send given hex value        'hex type value'         (value: ZZPBSBNNDx)" << endl << endl
 		       << " scan      - scan ebus kown addresses    'scan'" << endl
 		       << "           - scan ebus all addresses     'scan full'" << endl
-		       << "           - show results                'scan result'" << endl << endl
+		       << "           - show scan results           'scan result'" << endl << endl
  		       << " log       - change log areas            'log areas area,area,..' (areas: bas|net|bus|upd|all)" << endl
 		       << "           - change log level            'log level level'        (level: error|event|trace|debug)" << endl << endl
 		       << " raw       - toggle log raw data         'raw'" << endl

src/lib/ebus/data.cpp

@@ -373,7 +373,8 @@ void SingleDataField::dump(ostream& output)
 result_t SingleDataField::read(const PartType partType,
 		SymbolString& data, unsigned char offset,
 		ostringstream& output, bool leadingSeparator,
-		bool verbose, char separator)
+		bool verbose, const char* filterName,
+		char separator)
 {
 	if (partType != m_partType)
 		return RESULT_OK;
@@ -389,11 +390,11 @@ result_t SingleDataField::read(const PartType partType,
 	default:
 		return RESULT_ERR_INVALID_PART;
 	}
-	if (isIgnored() == true) {
+	if (isIgnored() == true || (filterName != NULL && m_name != filterName)) {
 		if (offset + m_length > data.size()) {
 			return RESULT_ERR_INVALID_POS;
 		}
-		return RESULT_OK;
+		return RESULT_EMPTY;
 	}
 
 	if (leadingSeparator == true)
@@ -1111,9 +1112,10 @@ void DataFieldSet::dump(ostream& output)
 result_t DataFieldSet::read(const PartType partType,
 		SymbolString& data, unsigned char offset,
 		ostringstream& output, bool leadingSeparator,
-		bool verbose, char separator)
+		bool verbose, const char* filterName,
+		char separator)
 {
-	bool previousFullByteOffset = true;
+	bool previousFullByteOffset = true, found = false;
 	for (vector<SingleDataField*>::iterator it = m_fields.begin(); it < m_fields.end(); it++) {
 		SingleDataField* field = *it;
 		if (partType != pt_any && field->getPartType() != partType)
@@ -1122,15 +1124,17 @@ result_t DataFieldSet::read(const PartType partType,
 		if (previousFullByteOffset == false && field->hasFullByteOffset(false) == false)
 			offset--;
 
-//cout<<"read "<<field->getName().c_str()<<" in part "<<static_cast<unsigned>(field->getPartType())<<" offset "<<static_cast<unsigned>(offsets[field->getPartType()])<<endl;
+		result_t result = field->read(partType, data, offset, output, leadingSeparator, verbose, filterName, separator);
-		result_t result = field->read(partType, data, offset, output, leadingSeparator, verbose, separator);
 
-		if (result != RESULT_OK)
+		if (result < RESULT_OK)
 			return result;
 
 		offset += field->getLength(partType);
 		previousFullByteOffset = field->hasFullByteOffset(true);
-		leadingSeparator |= field->isIgnored() == false;
+		if (result != RESULT_EMPTY) {
+			found = true;
+			leadingSeparator = true;
+		}
 	}
 
 	if (verbose == true) {
@@ -1138,7 +1142,7 @@ result_t DataFieldSet::read(const PartType partType,
 			output << " [" << m_comment << "]";
 	}
 
-	return RESULT_OK;
+	return found == true ? RESULT_OK : RESULT_EMPTY;
 }
 
 result_t DataFieldSet::write(istringstream& input,

src/lib/ebus/data.h

@@ -183,13 +183,17 @@ public:
 	 * @param leadingSeparator whether to prepend a separator before the formatted value.
 	 * @param verbose whether to prepend the name, append the unit (if present), and append
 	 * the comment in square brackets (if present).
+	 * @param filterName the optional name of a field to limit the output to.
 	 * @param separator the separator character between multiple fields.
-	 * @return @a RESULT_OK on success (or if the partType does not match), or an error code.
+	 * @return @a RESULT_OK on success (or if the partType does not match),
+	 * or @a RESULT_EMPTY if the field was skipped (either ignored or due to @a filterName),
+	 * or an error code.
 	 */
 	virtual result_t read(const PartType partType,
 			SymbolString& data, unsigned char offset,
 			ostringstream& output, bool leadingSeparator=false,
-			bool verbose=false, char separator=UI_FIELD_SEPARATOR) = 0;
+			bool verbose=false, const char* filterName=NULL,
+			char separator=UI_FIELD_SEPARATOR) = 0;
 	/**
 	 * @brief Writes the value to the master or slave @a SymbolString.
 	 * @param input the @a istringstream to parse the formatted value from.
@@ -270,7 +274,8 @@ public:
 	virtual result_t read(const PartType partType,
 			SymbolString& data, unsigned char offset,
 			ostringstream& output, bool leadingSeparator=false,
-			bool verbose=false, char separator=UI_FIELD_SEPARATOR);
+			bool verbose=false, const char* filterName=NULL,
+			char separator=UI_FIELD_SEPARATOR);
 	// @copydoc
 	virtual result_t write(istringstream& input,
 			const PartType partType, SymbolString& data,
@@ -569,7 +574,8 @@ public:
 	virtual result_t read(const PartType partType,
 			SymbolString& data, unsigned char offset,
 			ostringstream& output, bool leadingSeparator=false,
-			bool verbose=false, char separator=UI_FIELD_SEPARATOR);
+			bool verbose=false, const char* filterName=NULL,
+			char separator=UI_FIELD_SEPARATOR);
 	// @copydoc
 	virtual result_t write(istringstream& input,
 			const PartType partType, SymbolString& data,

src/lib/ebus/message.cpp

@@ -293,7 +293,9 @@ result_t Message::prepareSlave(SymbolString& slaveData)
 }
 
 result_t Message::decode(const PartType partType, SymbolString& data,
-		ostringstream& output, bool leadingSeparator, bool verbose, char separator)
+		ostringstream& output, bool leadingSeparator,
+		bool verbose, const char* filterName,
+		char separator)
 {
 	unsigned char offset;
 	if (partType == pt_masterData)
@@ -301,7 +303,7 @@ result_t Message::decode(const PartType partType, SymbolString& data,
 	else
 		offset = 0;
 	int startPos = output.str().length();
-	result_t result = m_data->read(partType, data, offset, output, leadingSeparator, verbose, separator);
+	result_t result = m_data->read(partType, data, offset, output, leadingSeparator, verbose, filterName, separator);
 	time(&m_lastUpdateTime);
 	if (result != RESULT_OK) {
 		m_lastValue.clear();

src/lib/ebus/message.h

@@ -167,11 +167,14 @@ public:
 	 * @param leadingSeparator whether to prepend a separator before the formatted value.
 	 * @param verbose whether to prepend the name, append the unit (if present), and append
 	 * the comment in square brackets (if present).
+	 * @param filterName the optional name of a field to limit the output to.
 	 * @param separator the separator character between multiple fields.
 	 * @return @a RESULT_OK on success, or an error code.
 	 */
 	result_t decode(const PartType partType, SymbolString& data,
-			ostringstream& output, bool leadingSeparator=false, bool verbose=false, char separator=UI_FIELD_SEPARATOR);
+			ostringstream& output, bool leadingSeparator=false,
+			bool verbose=false, const char* filterName=NULL,
+			char separator=UI_FIELD_SEPARATOR);
 
 	/**
 	 * @brief Get the last decoded value.

src/lib/ebus/result.cpp

@@ -27,6 +27,7 @@ const char* getResultCode(result_t resultCode) {
 	case RESULT_OK:               return "success";
 	case RESULT_IN_ESC:           return "success: escape sequence received";
 	case RESULT_SYN:              return "success: SYN received";
+	case RESULT_EMPTY:            return "success: empty";
 	case RESULT_ERR_GENERIC_IO:   return "ERR: generic I/O error";
 	case RESULT_ERR_DEVICE:       return "ERR: generic device error";
 	case RESULT_ERR_SEND:         return "ERR: send error";

src/lib/ebus/result.h

@@ -24,6 +24,7 @@ static const int RESULT_OK = 0;                 // success
 
 static const int RESULT_IN_ESC = 1;             // start of escape sequence received
 static const int RESULT_SYN = 2;                // regular SYN after message received
+static const int RESULT_EMPTY = 3;              // empty result
 
 static const int RESULT_ERR_GENERIC_IO = -1;    // generic I/O error (usually fatal)
 static const int RESULT_ERR_DEVICE = -2;        // generic device error (usually fatal)