Generic indicator factory

Src/Myc.Data.Records.pas

@@ -86,7 +86,8 @@ type
         function GetRawData: Pointer; inline;
 
     public
-        constructor Create(const ALayout: TLayout);
+        constructor Create(const ALayout: TLayout); overload;
+        constructor Create(const ALayout: TLayout; const ABuffer: TBytes); overload;
 
         class operator Finalize(var Dest: TDataRecord);
         class operator Assign(var Dest: TDataRecord; const [ref] Src: TDataRecord);
@@ -120,13 +121,17 @@ const
 
 { TDataRecord }
 
-constructor TDataRecord.Create(const ALayout: TLayout);
+constructor TDataRecord.Create(const ALayout: TLayout; const ABuffer: TBytes);
 begin
     FLayout := ALayout;
+    FBuffer := ABuffer;
+end;
 
-    SetLength(FBuffer, FLayout.Size);
-    for var i := 0 to High(FLayout.Fields) do
-        FLayout.Fields[i].InitField(FBuffer);
+constructor TDataRecord.Create(const ALayout: TLayout);
+begin
+    var buf: TBytes;
+    SetLength(buf, ALayout.Size);
+    Create(ALayout, buf);
 end;
 
 procedure TDataRecord.CopyFrom<T>(const Src: T);
@@ -154,12 +159,19 @@ end;
 
 class function TDataRecord.FromRecord<T>: TDataRecord;
 begin
-    Result.Create(TLayout.FromRecord<T>);
+    var layout := TLayout.FromRecord<T>;
+    var buf: TBytes;
+
+    SetLength(buf, layout.Size);
+    for var i := 0 to High(layout.Fields) do
+        layout.Fields[i].InitField(buf);
+
+    Result.Create(layout, buf);
 end;
 
 class function TDataRecord.FromRecord<T>(const Src: T): TDataRecord;
 begin
-    Result.Create(TLayout.FromRecord<T>);
+    Result := FromRecord<T>;
     Result.CopyFrom<T>(Src);
 end;
 
@@ -226,7 +238,9 @@ begin
     if Dest.FLayout.FFields <> Src.FLayout.FFields then
     begin
         Finalize(Dest);
-        Dest.Create(Src.Layout);
+        var buf: TBytes;
+        SetLength(buf, Length(Dest.FBuffer));
+        Dest.Create(Src.Layout, buf);
     end;
 
     for var i := 0 to High(Dest.Layout.Fields) do