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[quote author=eny link=msg=836 date=1280488443]
I've found a surprisinlgy simple workaround for this problem.
It seems the compiler is confused by the TLongWordRec usage in SwapEndianLongWord (ImagingUtility.pas) together with a call to this function with a pure constant value parameter:[code]
      LongVal := SwapEndianLongWord(16);               // Extra data size (4 (mask size) + 4 (ranges size) + 8 (name))[/code]
It's perfectly good syntax, but the compiler gets confused and raises an internal error.

I've found 2 different ways of implementing a quick fix that both work (as far as I can see):
1. Create a simple variant record type and use that as a typecast instead of TLongWordRec.
[code]TSimpleLWRec = packed record
  B0, B1, B2, B3: byte;
end;
...
  // In SwapEndianLongWord:
  TSimpleLWRec(Result).B0 = TSimpleLWRec(Value).B3;
  TSimpleLWRec(Result).B1 = TSimpleLWRec(Value).B2;
  //etc...
[/code]

2. Cheat on the compiler by not passing '16' as an argument, but use a local variable instead:
[code]      LongVal := 16;
      LongVal := SwapEndianLongWord(LongVal);               // Extra data size (4 (mask size) + 4 (ranges size) + 8 (name))
[/code]
LongVal is already there and the assignment introduces little overhead.
[/quote]

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Topic summary

Posted by Galfar

- 11 August 2010, 16:24:13

Thanks for the tip for avoiding internal error.
Have you reported it to FPC bug tracker?

Posted by eny

- 30 July 2010, 13:14:03

I've found a surprisinlgy simple workaround for this problem.
It seems the compiler is confused by the TLongWordRec usage in SwapEndianLongWord (ImagingUtility.pas) together with a call to this function with a pure constant value parameter:

Code Select


      LongVal := SwapEndianLongWord(16);               // Extra data size (4 (mask size) + 4 (ranges size) + 8 (name))

It's perfectly good syntax, but the compiler gets confused and raises an internal error.

I've found 2 different ways of implementing a quick fix that both work (as far as I can see):
1. Create a simple variant record type and use that as a typecast instead of TLongWordRec.

Code Select

TSimpleLWRec = packed record
  B0, B1, B2, B3: byte;
end;
...
  // In SwapEndianLongWord:
  TSimpleLWRec(Result).B0 = TSimpleLWRec(Value).B3;
  TSimpleLWRec(Result).B1 = TSimpleLWRec(Value).B2;
  //etc...

2. Cheat on the compiler by not passing '16' as an argument, but use a local variable instead:

Code Select

      LongVal := 16;
      LongVal := SwapEndianLongWord(LongVal);               // Extra data size (4 (mask size) + 4 (ranges size) + 8 (name))

LongVal is already there and the assignment introduces little overhead.

Posted by Galfar

- 23 July 2010, 23:42:47

Report internal compiler error to FPC bug tracker please, there's not much I can do about this.
Or could you try some other FPC versions too?

Posted by eny

- 23 July 2010, 23:18:44

VIL 264; lazarus daily snapshot 26788 (July 23rd) with FPC 2.4.3 on WinXP SP3.
When adding some units to the uses list (Imaging, ImagingTypes, ImagingClasses, ImagingCanvases) an internal error is raised on line 705 of ImagingPSD.

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