C++ pointer to byte array --> Delphi

[DeddyH]

I am not that familiar with C/C++, sry.

[Namenloser]

Looks mostly good to me, but I would pay some extra attention to the type casts. I am not sure if ord() always gives the correct result here. In some places the type cast might be done to truncate a value. For example, (ushort)foo gives us the lowest 16 bits of foo .

And in the top code, I think you can get rid of ord() entirely, if you've correctly translated char as byte.

[WojTec]

I completely don't understand what for is type casts from byte Variables whare are moved results can store entire data without truncating or something alse. What do you think?

Ord() is used, because AValue is string, I plan change it to TBytes.

[Namenloser]

Zitat von WojTec:

Variables whare are moved results can store entire data without truncating or something alse. What do you think?

I am not sure what you mean by that sentence, "whare" was not a word last time I checked .

I assume you wanted to say that the typecasts are unnecessary, which may be true. I didn't examine the code that closely, I was just saying that you should pay attention to that.

[WojTec]

Zitat von Namenloser:

"whare" was not a word last time I checked .

Today I confused keys, because my brain is overloaded with obscure C syntax

Zitat von Namenloser:

I assume you wanted to say that the typecasts are unnecessary

Yes. But on the other hand code is written by professional, I'll try contact him.

[Der schöne Günther]

You ignored me

I believe I explained why the upcast is necessary.

[Namenloser]

Zitat von Der schöne Günther:

You ignored me

I believe I explained why the upcast is necessary.

I think in Delphi the upcast is done automatically by the compiler when the result is stored in a variable that is bigger than the operands.

Delphi-Quellcode:

var
  b: Byte;
  i: integer;
begin
  b := 255;
  i := b shl 2;
  // i should now hold the value 510
end

[WojTec]

Zitat von Der schöne Günther:

You ignored me

I believe I explained why the upcast is necessary.

Oh, no, I didn't ignored you

You explained, but I still don't understand.

I checked it in this sample:

Delphi-Quellcode:

const
  C: Char = 'X';
var
  B: Byte absolute C;
begin
  ShowMessage(IntToStr(B shl 8));  // 22528
  ShowMessage(IntToStr((256*Byte(C)) shl 8)); // 5767168
  ShowMessage(IntToStr(Cardinal(Ord(C) shl 8))); // 22528
end;

Could you check in C++ what it returns? In Delphi I have 2901454111 for 'Delphi' string and 4357 seed.

Code:

#define mix(a,b,c) \
{ \
  a -= b; a -= c; a ^= ( c >> 13 ); \
  b -= c; b -= a; b ^= ( a << 8 ); \
  c -= a; c -= b; c ^= ( b >> 13 ); \
  a -= b; a -= c; a ^= ( c >> 12 ); \
  b -= c; b -= a; b ^= ( a << 16 ); \
  c -= a; c -= b; c ^= ( b >> 5 ); \
  a -= b; a -= c; a ^= ( c >> 3 ); \
  b -= c; b -= a; b ^= ( a << 10 ); \
  c -= a; c -= b; c ^= ( b >> 15 ); \
}