TDBF - Issue with TTimestamp and TDateTime Get Function
lazarus / 63-Database

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dparnaby · 2017-04-20 09:35

I use TDBF extensively in my Accounting project front end to firebird
.

The assignment  to "result"  as below is not robust as it will reject
a Tdatetime that has zero time element.
**********************************************************************
********************************************
 Result := (Unaligned(PInteger(Src)^) <> 0) and
(Unaligned(PInteger(PChar(Src)+4)^) <> 0);
**********************************************************************
********************************************


SEE ALTERED SOURCE BELOW- THERE  IS A ROBUSTNESS ISSUE

as the function GetFieldDataFromDef requires  a time value other than
zero to process correctly where FDateTimeHandling is set to
dtDateTime  .

Regards - David Parnaby - Durban 
**********************************************************************
*****************************************

Source DBF_DBFFile starts line  1697

function TDbfFile.GetFieldDataFromDef(AFieldDef: TDbfFieldDef;
DataType: TFieldType;
  Src, Dst: Pointer; NativeFormat: boolean): Boolean;
    '@':
      begin
        {*********************in house
amendments***********************}
        if FDateTimeHandling = dtBDETimeStamp then
          begin
            Result := (Unaligned(PInteger(Src)^) <> 0) and
(Unaligned(PInteger(PChar(Src)+4)^) <> 0);
            if Result and (Dst <> nil) then
            begin
              SwapInt64BE(Src, Dst);
                date := BDETimeStampToDateTime(PDouble(Dst)^);
             SaveDateToDst;
             end;
        end else
        if FDateTimeHandling = dtDateTime then
        begin
       //-Takenout->
    ******************************************************************
************************************************
//    Result := (Unaligned(PInteger(Src)^) <> 0) and 
 (Unaligned(PInteger(PChar(Src)+4)^) <> 0);
   *******************************************************************
***********************************************
          if  (Dst <> nil) then
          begin
            SwapInt64BE(Src, Dst);
             { zero date can cause exceptions }
             if Unaligned(PInteger(Src)^) =0 then
               date:=1 else
                 date := PDateTime(Dst)^;
           SaveDateToDst;
          end;
       end;
      {*********************in house
amendments***********************}

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Handoko · 2017-06-07 18:51

Hello dparnaby.

Can you please provide us the compilable source for us to try? You can
write a demo project that shows the issue. Zip them (except the
executable and lib folder) and send it to this forum. Please also
provide the sample data.