Still getting AV with 5.1.9, attached is a demo

Comments

• Bill E

  November 2014 edited 7:53AM

  Just tried 5.1.10 and still has the error.
• Bill E

  November 2014 edited 7:53AM

  rhodesv wrote: »

  Has anyone found anything here as a work around yet?

  
  They just released (11/27) 5.1.11 but it still has the bug. From talking with support it seems to occur in XE7 but works in XE6. I have not verified that.
  
  I purchased the source a couple days ago in order to try and fix this problem. Wish me luck. If it does work in XE6 then I can run 2 virtual machines (one XE6 and the other XE7) and step through code side by side (2 monitors) to see where the point of failure is. If it is a XE7 bug then I will try to find a workaround.
  
  
• Bill E

  November 2014 edited 7:53AM

  rhodesv wrote: »

  Has anyone found anything here as a work around yet?

  
  
  Today is thanksgiving and I need to stop working, but I do see something suspicious and a possible fix:
  
  Below is the code that is blowing up with an AV
  

  function CmapTableClass.LoadSignedCmapSegment(segment_ptr: Pointer; segment_count: Integer ): TSmallintArray;
  var
    i: Integer;
    p : TWordArray;
  begin
      SetLength(Result, segment_count);
      p := segment_ptr;
      i := 0;
      while ((i < segment_count)) do
      begin
          Result[i] := TTF_Helpers.SwapInt16(p[i]);
          inc(i)
      end;
  end;
  

  Here is another peice of code that works I think:
  

  function CmapTableClass.LoadCmapSegment(segment_ptr: Pointer; segment_count: Integer): TWordArray;
  var
    i: Integer;
    ptr: ^Word;
  begin
      ptr := segment_ptr;
      SetLength(Result, segment_count);
      i := 0;
      while ((i < segment_count)) do
      begin
          Result[i] := TTF_Helpers.SwapUInt16(ptr^);
          Inc(i);
          Inc(ptr);
      end;
  end;
  

  
  
  See the difference, they are using a dynamic array in one (TWordArray) and then regular old style ^Word in the other. I am suspicious of the pointer assignment to the dynamic array because the compiler does reference counting to them. I have to leave for the day but I wonder if getting rid of the dynamic array cast and using old style pointers with Inc would fix the problem.
  
  
• Bill E

  November 2014 edited 7:53AM

  I fixed it in my source, if you have the source change the source in unit frxCmapTableClass line 193 to the below:
  
  The solution was to get rid of casting a pointer to a dynamic array.
  

      function CmapTableClass.LoadSignedCmapSegment(segment_ptr: Pointer; segment_count: Integer ): TSmallintArray;
      var
        i: Integer;
        WordPtr : ^Word;
      begin
          SetLength(Result, segment_count);
          WordPtr := segment_ptr;
          i := 0;
          while ((i < segment_count)) do
          begin
              Result[i] := TTF_Helpers.SwapInt16(WordPtr^);
              inc(i);
              Inc(WordPtr);
          end;
      end;
  
• Udo Treichel

  November 2014 edited November 2014

  Thank you, Bill E,
  
  your fix saved my a.. today. I hope FR will use it or something similiar in their stable realease and publish it for XE 7 asap...
• Bill E

  December 2014 edited 7:53AM

  I see there is a new 5.1.12 version. Does this version have this fix in it?