[fpc-devel] Packed record integers and x86_86

[DJ Coertzen]

On Wed, Mar 27, 2019 at 7:48 PM Christo Crause <christo.crause at gmail.com>
wrote:

>
>
> On Wed, 27 Mar 2019, 19:27 DJ Coertzen, <patrolliekaptein at gmail.com>
> wrote:
>
>> Hi there,
>>
>> I need a solution for a packed record containing 4-byte 32-bit integers
>> and cardinals, and other byte 8 bit and word 16 bit sized variables to
>> overlay over a stream.
>>
>> Example:
>> *type*
>> *  TMyBinaryHeader = packed record*
>> *    Sender    : Cardinal;*
>>
>> *    Target    : Cardinal;*
>>
>> *    Reference : Integer;    *
>>
>> *    Flags     : Word;*
>> *    CheckByte : Byte;*
>> *  end;*
>>
>> So on 32 bit systems, SizeOf(TMyBinaryHeader) will report 15 bytes. How
>> do I accomplish this on 64 bit platform and avoiding
>> "myprotocollib.pas(x,y) Error: Typecast has different size (4 -> 8) in
>> assignment" without having to port to ugly byte copy operations.
>>
>
> Perhaps use size explicit types such as uint32 and int32?
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Pointer arithmetic:
*for Indx := 0 to SizeOf(TTCPPackageHeader) - 1 do
Dec(Byte(Pointer(Cardinal(@x) + Indx)^), ARollCount);*
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