ArduCopter: reduce redundant event logging

We now only write state changes to the dataflash log when they have
changed.
Also replaced <tab> with <space> in AP_State.pde

ArduCopter/AP_State.pde

@@ -3,43 +3,55 @@
 
 void set_home_is_set(bool b)
 {
-    ap.home_is_set 	= b;
+    // if no change, exit immediately
+    if( ap.home_is_set == b )
+        return;
 
-	if(b) Log_Write_Event(DATA_SET_HOME);
+    ap.home_is_set 	= b;
+    if(b) {
+        Log_Write_Event(DATA_SET_HOME);
+    }
 }
 
 // ---------------------------------------------
 void set_armed(bool b)
 {
-	ap.armed = b;
+    // if no change, exit immediately
-	if(b){
+    if( ap.armed == b )
-		Log_Write_Event(DATA_ARMED);
+        return;
 
-	}else{
+    ap.armed = b;
-		Log_Write_Event(DATA_DISARMED);
+    if(b){
-	}
+        Log_Write_Event(DATA_ARMED);
+    }else{
+        Log_Write_Event(DATA_DISARMED);
+    }
 }
 
 // ---------------------------------------------
 void set_auto_armed(bool b)
 {
-	ap.auto_armed = b;
+    // if no change, exit immediately
-	if(b){
+    if( ap.auto_armed == b )
-		Log_Write_Event(DATA_AUTO_ARMED);
+        return;
-	}
+
+    ap.auto_armed = b;
+    if(b){
+        Log_Write_Event(DATA_AUTO_ARMED);
+    }
 }
 
 // ---------------------------------------------
 void set_simple_mode(bool b)
 {
-	if(ap.simple_mode != b){
+    if(ap.simple_mode != b){
-		if(b){
+        if(b){
-			Log_Write_Event(DATA_SET_SIMPLE_ON);
+            Log_Write_Event(DATA_SET_SIMPLE_ON);
-		}else{
+        }else{
-			Log_Write_Event(DATA_SET_SIMPLE_OFF);
+            Log_Write_Event(DATA_SET_SIMPLE_OFF);
-		}
+        }
-	}
+        ap.simple_mode = b;
-	ap.simple_mode = b;
+    }
 }
 
 // ---------------------------------------------
@@ -69,25 +81,33 @@ static void set_failsafe(bool mode)
 // ---------------------------------------------
 void set_low_battery(bool b)
 {
-	ap.low_battery = b;
+    ap.low_battery = b;
 }
 
 // ---------------------------------------------
 void set_takeoff_complete(bool b)
 {
-	if(b){
+    // if no change, exit immediately
-		Log_Write_Event(DATA_TAKEOFF);
+    if( ap.takeoff_complete == b )
-	}
+        return;
-	ap.takeoff_complete = b;
+
+    if(b){
+        Log_Write_Event(DATA_TAKEOFF);
+    }
+    ap.takeoff_complete = b;
 }
 
 // ---------------------------------------------
 void set_land_complete(bool b)
 {
-	if(b){
+    // if no change, exit immediately
-		Log_Write_Event(DATA_LAND_COMPLETE);
+    if( ap.land_complete == b )
-	}
+        return;
-	ap.land_complete = b;
+
+    if(b){
+        Log_Write_Event(DATA_LAND_COMPLETE);
+    }
+    ap.land_complete = b;
 }
 
 // ---------------------------------------------
@@ -100,41 +120,40 @@ void set_alt_change(uint8_t flag){
     }
 
     // update flag
-	alt_change_flag = flag;
+    alt_change_flag = flag;
 
-	if(flag == REACHED_ALT){
+    if(flag == REACHED_ALT){
-		Log_Write_Event(DATA_REACHED_ALT);
+        Log_Write_Event(DATA_REACHED_ALT);
 
-	}else if(flag == ASCENDING){
+    }else if(flag == ASCENDING){
-		Log_Write_Event(DATA_ASCENDING);
+        Log_Write_Event(DATA_ASCENDING);
 
-	}else if(flag == DESCENDING){
+    }else if(flag == DESCENDING){
-		Log_Write_Event(DATA_DESCENDING);
+        Log_Write_Event(DATA_DESCENDING);
-	}
+    }
 }
 
 void set_compass_healthy(bool b)
 {
-	if(ap.compass_status != b){
+    if(ap.compass_status != b){
-		if(false == b){
+        if(false == b){
-			Log_Write_Event(DATA_LOST_COMPASS);
+            Log_Write_Event(DATA_LOST_COMPASS);
-		}
+        }
-	}
+    }
-	ap.compass_status = b;
+    ap.compass_status = b;
 }
 
 void set_gps_healthy(bool b)
 {
-	if(ap.gps_status != b){
+    if(ap.gps_status != b){
-		if(false == b){
+        if(false == b){
-			Log_Write_Event(DATA_LOST_GPS);
+            Log_Write_Event(DATA_LOST_GPS);
-		}
+        }
-	}
+    }
-	ap.gps_status = b;
+    ap.gps_status = b;
 }
 
 void dump_state()
 {
     cliSerial->printf("st: %u\n",ap.value);
-	//cliSerial->printf("%u\n", *(uint16_t*)&ap);
 }