C++ pointer to byte array --> Delphi

[Mikkey]

Zitat:

Zitat von WojTec (Beitrag 1238172)

It mean if case 11 then process all, if 10 than all instead above, etc.?

And what about rest operations? Indexes are valid? 256 multiply is required?

Don't worry with 256: Multiplying with 256 is the same as shifting left 8 bits.

You must invent some construct for the C-Case, bcse the Delphi case has implicit C-"break"s. Perhaps like:

Delphi-Quellcode:

if length  = 11 then ...
if length >= 10 then ...
if length >=  9 then ...
...

[Namenloser]

Looks mostly good to me, but I would pay some extra attention to the type casts. I am not sure if

Delphi-Quellcode:

ord()

always gives the correct result here. In some places the type cast might be done to truncate a value. For example,

Delphi-Quellcode:

(ushort)foo

gives us the lowest 16 bits of

Delphi-Quellcode:

foo

.

And in the top code, I think you can get rid of

Delphi-Quellcode:

ord()

entirely, if you've correctly translated char as byte.

[WojTec]

I completely don't understand what for is type casts from byte :o 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:

Zitat von WojTec (Beitrag 1238189)

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:

Zitat von Namenloser (Beitrag 1238200)

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

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

Zitat:

Zitat von Namenloser (Beitrag 1238200)

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:

Zitat von Der schöne Günther (Beitrag 1238237)

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:

Zitat von Der schöne Günther (Beitrag 1238237)

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 ); \
}