refactor: consolidate duplicate if (isNew) checks (S2589)

lib/channels/dchannel/Dchannel.cs

@@ -102,20 +102,16 @@ public sealed class Dchannel : ITValuePublisher
         if (isNew)
         {
             _p_state = _state;
-        }
-        else
-        {
-            _state = _p_state;
-        }
-
-        if (isNew)
-        {
             _index++;
             if (_count < _period)
             {
                 _count++;
             }
         }
+        else
+        {
+            _state = _p_state;
+        }
 
         int bufIdx = (int)(_index % _period);
         var (high, low) = GetValid(input.High, input.Low);

lib/channels/fcb/Fcb.cs

@@ -221,20 +221,16 @@ public sealed class Fcb : ITValuePublisher
         if (isNew)
         {
             _p_state = _state;
-        }
-        else
-        {
-            _state = _p_state;
-        }
-
-        if (isNew)
-        {
             _index++;
             if (_count < _period)
             {
                 _count++;
             }
         }
+        else
+        {
+            _state = _p_state;
+        }
 
         var (high, low) = GetValid(input.High, input.Low);
 

lib/channels/mmchannel/Mmchannel.cs

@@ -101,20 +101,16 @@ public sealed class Mmchannel : ITValuePublisher
         if (isNew)
         {
             _p_state = _state;
-        }
-        else
-        {
-            _state = _p_state;
-        }
-
-        if (isNew)
-        {
             _index++;
             if (_count < _period)
             {
                 _count++;
             }
         }
+        else
+        {
+            _state = _p_state;
+        }
 
         int bufIdx = (int)(_index % _period);
         var (high, low) = GetValid(input.High, input.Low);

lib/channels/pchannel/Pchannel.cs

@@ -197,20 +197,16 @@ public sealed class Pchannel : ITValuePublisher
         if (isNew)
         {
             _p_state = _state;
-        }
-        else
-        {
-            _state = _p_state;
-        }
-
-        if (isNew)
-        {
             _index++;
             if (_count < _period)
             {
                 _count++;
             }
         }
+        else
+        {
+            _state = _p_state;
+        }
 
         int bufIdx = (int)(_index % _period);
         var (high, low) = GetValid(input.High, input.Low);

lib/trends_IIR/mgdi/Mgdi.cs

@@ -66,17 +66,13 @@ public sealed class Mgdi : AbstractBase
         if (isNew)
         {
             _p_state = _state;
+            _state.Count++;
         }
         else
         {
             _state = _p_state;
         }
 
-        if (isNew)
-        {
-            _state.Count++;
-        }
-
         double price = input.Value;
         if (!double.IsFinite(price))
         {