From ecd176042ecbaa5047ab0f6cbf1fb0a9e8753f3c Mon Sep 17 00:00:00 2001
From: Harald Barth <haba@kth.se>
Date: Mon, 26 Oct 2020 00:56:25 +0100
Subject: [PATCH] checkAll() only checks one now (and should be renamed)

---
 DCCEXParser.cpp |  3 +--
 Sensors.cpp     | 31 +++++++++++++++++--------------
 Sensors.h       |  1 +
 3 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/DCCEXParser.cpp b/DCCEXParser.cpp
index e958ce5..712313c 100644
--- a/DCCEXParser.cpp
+++ b/DCCEXParser.cpp
@@ -360,8 +360,7 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
         return;
 
     case 'Q': // SENSORS <Q>
-        Sensor::checkAll(NULL);    // Update, don't print changes
-        Sensor::printAll(stream);  // Print all
+        Sensor::printAll(stream);
         return;
 
     case 's': // <s>
diff --git a/Sensors.cpp b/Sensors.cpp
index e0913a2..b9a9c9d 100644
--- a/Sensors.cpp
+++ b/Sensors.cpp
@@ -72,26 +72,27 @@ decide to ignore the <q ID> return and only react to <Q ID> triggers.
 
 ///////////////////////////////////////////////////////////////////////////////
 //
-// checks all defined sensors and prints _changed_ sensor states
+// checks one defined sensors and prints _changed_ sensor state
 // to stream unless stream is NULL in which case only internal
-// state is updated
+// state is updated. Then advances to next sensor which will
+// be checked att next invocation.
 //
 ///////////////////////////////////////////////////////////////////////////////
 
 void Sensor::checkAll(Print *stream){
+
+  if (firstSensor == NULL) return;
+  if (readingSensor == NULL) readingSensor=firstSensor;
+  readingSensor->signal=readingSensor->signal*(1.0-SENSOR_DECAY)+digitalRead(readingSensor->data.pin)*SENSOR_DECAY;
   
-  for(Sensor * tt=firstSensor;tt!=NULL;tt=tt->nextSensor){
-    tt->signal=tt->signal*(1.0-SENSOR_DECAY)+digitalRead(tt->data.pin)*SENSOR_DECAY;
-
-    if(!tt->active && tt->signal<0.5){
-      tt->active=true;
-      if (stream != NULL) StringFormatter::send(stream, F("<Q %d>"), tt->data.snum);
-    } else if(tt->active && tt->signal>0.9){
-      tt->active=false;
-      if (stream != NULL) StringFormatter::send(stream, F("<q %d>"), tt->data.snum);
-    }
-  } // loop over all sensors
-
+  if(!readingSensor->active && readingSensor->signal<0.5){
+    readingSensor->active=true;
+    if (stream != NULL) StringFormatter::send(stream, F("<Q %d>"), readingSensor->data.snum);
+  } else if(readingSensor->active && readingSensor->signal>0.9){
+    readingSensor->active=false;
+    if (stream != NULL) StringFormatter::send(stream, F("<q %d>"), readingSensor->data.snum);
+  }
+  readingSensor=readingSensor->nextSensor;
 } // Sensor::checkAll
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -159,6 +160,7 @@ bool Sensor::remove(int n){
   else
     pp->nextSensor=tt->nextSensor;
 
+  if (readingSensor==tt) readingSensor=tt->nextSensor;
   free(tt);
 
   return true;
@@ -196,3 +198,4 @@ void Sensor::store(){
 ///////////////////////////////////////////////////////////////////////////////
 
 Sensor *Sensor::firstSensor=NULL;
+Sensor *Sensor::readingSensor=NULL;
diff --git a/Sensors.h b/Sensors.h
index 717da69..901d1e5 100644
--- a/Sensors.h
+++ b/Sensors.h
@@ -31,6 +31,7 @@ struct SensorData {
 
 struct Sensor{
   static Sensor *firstSensor;
+  static Sensor *readingSensor;
   SensorData data;
   boolean active;
   float signal;