From 6b09ca056e41bb412f76a03028e28ba3f81763c3 Mon Sep 17 00:00:00 2001
From: Bernhard Kirchen <schlimmchen@posteo.net>
Date: Mon, 17 Jun 2024 21:02:04 +0200
Subject: [PATCH] Feature: SML power meters: reset SML decoder

implement a function which allows to reset the SML decoder. this new
function is used after a datagram ends. for the SML HTTP power meter
this is simple: after all bytes from the request's answer have been
decoded, we reset the decoder. for the SML serial power meter, we
perform the reset after a datagram ended based on timing (no new bytes
have been received for a specific amount of time).
---
 include/PowerMeterSml.h     |  1 +
 lib/SMLParser/sml.cpp       |  6 ++++++
 lib/SMLParser/sml.h         |  1 +
 src/PowerMeterHttpSml.cpp   |  2 ++
 src/PowerMeterSerialSml.cpp |  2 ++
 src/PowerMeterSml.cpp       | 10 ++++++++--
 6 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/PowerMeterSml.h b/include/PowerMeterSml.h
index a0d614201..79e37ab9a 100644
--- a/include/PowerMeterSml.h
+++ b/include/PowerMeterSml.h
@@ -20,6 +20,7 @@ class PowerMeterSml : public PowerMeterProvider {
     explicit PowerMeterSml(char const* user)
         : _user(user) { }
 
+    void reset();
     void processSmlByte(uint8_t byte);
 
 private:
diff --git a/lib/SMLParser/sml.cpp b/lib/SMLParser/sml.cpp
index 574dc12df..e330ef689 100644
--- a/lib/SMLParser/sml.cpp
+++ b/lib/SMLParser/sml.cpp
@@ -189,6 +189,12 @@ void checkMagicByte(unsigned char &byte)
   }
 }
 
+void smlReset(void)
+{
+  len = 4; // expect start sequence
+  currentState = SML_START;
+}
+
 sml_states_t smlState(unsigned char currentByte)
 {
   unsigned char size;
diff --git a/lib/SMLParser/sml.h b/lib/SMLParser/sml.h
index 6830dcc67..de844a4dc 100644
--- a/lib/SMLParser/sml.h
+++ b/lib/SMLParser/sml.h
@@ -92,6 +92,7 @@ typedef enum {
   SML_COUNT = 255
 } sml_units_t;
 
+void smlReset(void);
 sml_states_t smlState(unsigned char byte);
 bool smlOBISCheck(const unsigned char *obis);
 void smlOBISManufacturer(unsigned char *str, int maxSize);
diff --git a/src/PowerMeterHttpSml.cpp b/src/PowerMeterHttpSml.cpp
index 3331603ee..7149e12a8 100644
--- a/src/PowerMeterHttpSml.cpp
+++ b/src/PowerMeterHttpSml.cpp
@@ -107,5 +107,7 @@ String PowerMeterHttpSml::poll()
         processSmlByte(pStream->read());
     }
 
+    PowerMeterSml::reset();
+
     return "";
 }
diff --git a/src/PowerMeterSerialSml.cpp b/src/PowerMeterSerialSml.cpp
index 41f845a00..123a10ddd 100644
--- a/src/PowerMeterSerialSml.cpp
+++ b/src/PowerMeterSerialSml.cpp
@@ -110,6 +110,8 @@ void PowerMeterSerialSml::pollingLoop()
 
         lastAvailable = 0;
 
+        PowerMeterSml::reset();
+
         lock.lock();
     }
 }
diff --git a/src/PowerMeterSml.cpp b/src/PowerMeterSml.cpp
index 021b48cd6..c44662104 100644
--- a/src/PowerMeterSml.cpp
+++ b/src/PowerMeterSml.cpp
@@ -30,6 +30,12 @@ void PowerMeterSml::doMqttPublish() const
 #undef PUB
 }
 
+void PowerMeterSml::reset()
+{
+    smlReset();
+    _cache = { std::nullopt };
+}
+
 void PowerMeterSml::processSmlByte(uint8_t byte)
 {
     switch (smlState(byte)) {
@@ -52,12 +58,12 @@ void PowerMeterSml::processSmlByte(uint8_t byte)
         case SML_FINAL:
             gotUpdate();
             _values = _cache;
-            _cache = { std::nullopt };
+            reset();
             MessageOutput.printf("[%s] TotalPower: %5.2f\r\n",
                     _user.c_str(), getPowerTotal());
             break;
         case SML_CHECKSUM_ERROR:
-            _cache = { std::nullopt };
+            reset();
             MessageOutput.printf("[%s] checksum verification failed\r\n",
                     _user.c_str());
             break;