* Add TestStreamFormat

rtl/objpas/classes/classes.inc

@@ -2727,7 +2727,29 @@ begin
   Output.FixupResourceHeader(FixupInfo);      // Insert real resource data size
 end;
 
+function TestStreamFormat(const Stream: TStream): TStreamOriginalFormat;
 
+const
+  StartChars = [#9, #10, #13, #11, 'o', 'O','i','I',' '];
+
+var
+  aPos: Int64;
+  Sig: Packed Array[0..3] of byte;
+  IntSig : Longint absolute sig;
+  
+begin
+  Result:=sofUnknown;
+  aPos:=Stream.Position;
+  IntSig:=0;
+  Stream.Read(Sig,SizeOf(Sig));
+  Stream.Seek(aPos,soBeginning);
+  if (Sig[0]=$FF) or (IntSig=LongInt(FilerSignature)) or (IntSig=LongInt(FilerSignature1)) or (IntSig=0) then
+    Result:=sofBinary
+  else if (AnsiChar(Sig[0]) in StartChars) then
+    Result:=sofText
+  else if (Sig[1]=$BF) and (Sig[2]=$BB) and (Sig[3]=$EF) then
+    Result:=sofUTF8Text;
+end;
 
 { Utility routines }
 

rtl/objpas/classes/classesh.inc

@@ -2883,6 +2883,7 @@ procedure ObjectTextToBinary(Input, Output: TStream);
 
 procedure ObjectResourceToText(Input, Output: TStream);
 procedure ObjectTextToResource(Input, Output: TStream);
+function TestStreamFormat(const Stream: TStream): TStreamOriginalFormat;
 
 { Utility routines }