fpspreadsheet: Fix reverse order of rpn tokens when reading an xls file. Fix string formula reconstruction routine. Unit test passed again.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@3298 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/fpspreadsheet/fpspreadsheet.pas

@@ -2265,7 +2265,12 @@ begin
   fs := Workbook.FormatSettings;
   L := TStringList.Create;
   try
-    for i:=0 to Length(ACell^.RPNFormulaValue)-1 do begin
+    // We store the cell values and operation codes in a stringlist which serves
+    // as kind of stack. Therefore, we do not destroy the original formula array.
+    // We reverse the order of the items because in the next step stringlist
+    // items will subsequently be deleted, and this is much easier when going
+    // in reverse direction.
+    for i := Length(ACell^.RPNFormulaValue)-1 downto 0 do begin
       elem := ACell^.RPNFormulaValue[i];
       ptr := Pointer(elem.ElementKind);
       case elem.ElementKind of
@@ -2288,6 +2293,10 @@ begin
       end;
     end;
 
+    // Now we construct the string from the parts stored in the stringlist.
+    // Every item processed is deleted from the list for error detection.
+    // In order not to confuse mix up we start at the end of the list and
+    // work forward.
     i := L.Count-1;
     while (L.Count > 0) and (i >= 0) do begin
       fek := TFEKind(PtrInt(L.Objects[i]));
@@ -2332,7 +2341,7 @@ begin
           end;
         else
           if fek >= fekAdd then begin
-            elem := ACell^.RPNFormulaValue[i];
+            elem := ACell^.RPNFormulaValue[Length(ACell^.RPNFormulaValue) - 1 - i];
             s := '';
             for j:= i+elem.ParamsNum downto i+1 do begin
               if j < L.Count then begin

components/fpspreadsheet/xlscommon.pas

@@ -1458,7 +1458,12 @@ begin
   while (AStream.Position < p0 + n) and supported do begin
     token := AStream.ReadByte;
     case token of
-      INT_EXCEL_TOKEN_TREFV, INT_EXCEL_TOKEN_TREFR:
+      INT_EXCEL_TOKEN_TREFV:
+        begin
+          ReadRPNCellAddress(AStream, r, c, flags);
+          rpnItem := RPNCellValue(r, c, flags, rpnItem);
+        end;
+      INT_EXCEL_TOKEN_TREFR:
         begin
           ReadRPNCellAddress(AStream, r, c, flags);
           rpnItem := RPNCellRef(r, c, flags, rpnItem);
@@ -1540,7 +1545,7 @@ begin
     Result := false;
   end
   else begin
-    AFormula := CreateRPNFormula(rpnItem);
+    AFormula := CreateRPNFormula(rpnItem, true); // true --> we have to flip the order of items!
     Result := true;
   end;
 end;