From d573fff746a1679542750c73eadcdd528b1cf22a Mon Sep 17 00:00:00 2001
From: john30 <ebusd@johnm.de>
Date: Thu, 14 May 2015 09:50:28 +0200
Subject: [PATCH] added Symbol::compareMaster to avoid updating last message
 change time when only the querying master was modified

---
 src/lib/ebus/message.cpp | 23 +++++++++++++++++++----
 src/lib/ebus/symbol.h    | 15 +++++++++++++++
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/src/lib/ebus/message.cpp b/src/lib/ebus/message.cpp
index ec311078..277be4c6 100644
--- a/src/lib/ebus/message.cpp
+++ b/src/lib/ebus/message.cpp
@@ -318,9 +318,14 @@ result_t Message::prepareMaster(const unsigned char srcAddress, SymbolString& ma
 	result = m_data->write(input, pt_masterData, master, (unsigned char)(m_id.size() - 2), separator);
 	if (result != RESULT_OK)
 		return result;
-	if (master != m_lastMasterData) {
+	switch (master.compareMaster(m_lastMasterData)) {
+	case 1: // completely different
 		m_lastChangeTime = m_lastUpdateTime;
-		m_lastMasterData = master;
+		m_lastMasterData = masterData;
+		break;
+	case 2: // only master address is different
+		m_lastMasterData = masterData;
+		break;
 	}
 	masterData.addAll(master);
 	return result;
@@ -366,9 +371,14 @@ result_t Message::decode(const PartType partType, SymbolString& data,
 
 	time(&m_lastUpdateTime);
 	if (partType == pt_masterData) {
-		if (data != m_lastMasterData) {
+		switch (data.compareMaster(m_lastMasterData)) {
+		case 1: // completely different
 			m_lastChangeTime = m_lastUpdateTime;
 			m_lastMasterData = data;
+			break;
+		case 2: // only master address is different
+			m_lastMasterData = data;
+			break;
 		}
 	} else if (partType == pt_slaveData) {
 		if (data != m_lastSlaveData) {
@@ -397,9 +407,14 @@ result_t Message::decode(SymbolString& masterData, SymbolString& slaveData,
 	if (result == RESULT_EMPTY && !empty)
 		result = RESULT_OK; // OK if at least one part was non-empty
 	time(&m_lastUpdateTime);
-	if (masterData != m_lastMasterData) {
+	switch (masterData.compareMaster(m_lastMasterData)) {
+	case 1: // completely different
 		m_lastChangeTime = m_lastUpdateTime;
 		m_lastMasterData = masterData;
+		break;
+	case 2: // only master address is different
+		m_lastMasterData = masterData;
+		break;
 	}
 	if (slaveData != m_lastSlaveData) {
 		m_lastChangeTime = m_lastUpdateTime;
diff --git a/src/lib/ebus/symbol.h b/src/lib/ebus/symbol.h
index 7914934d..be31b9e7 100644
--- a/src/lib/ebus/symbol.h
+++ b/src/lib/ebus/symbol.h
@@ -93,6 +93,21 @@ public:
 	 */
 	bool operator!=(SymbolString& other) { return m_unescapeState!=other.m_unescapeState || m_data!=other.m_data; }
 
+	/**
+	 * Compares this instance to the other instance while treating both as master data (i.e. starting with the master address and ending with the CRC).
+	 * @param other the other instance.
+	 * @return 0 if this instance is equal to the other instance (i.e. both escaped or both unescaped and same symbols),
+	 * 1 if this instance is completely different to the other instance,
+	 * 2 if this instance only differs from the other instance in the first byte (the master address).
+	 */
+	int compareMaster(SymbolString& other) {
+		if (m_unescapeState!=other.m_unescapeState || m_data.size()!=other.m_data.size()) return 1;
+		if (m_data==other.m_data) return 0;
+		if (m_data.size()==1) return 2;
+		if (equal(m_data.begin()+1, m_data.end()-1, other.m_data.begin()+1)) return 2;
+		return 1;
+	}
+
 	/**
 	 * Appends a the symbol to the end of the symbol string and escapes/unescapes it if necessary.
 	 * @param value the symbol to append.