Increment hex string

Question

I'm trying to increment an hex string like this:

#$67#$1c#$87#$b1;
#$67#$1c#$87#$b2;
#$67#$1c#$87#$b3;

Here's my procedure:

var test : array [0..3] of char; intSequence : cardinal;

Sequence := #$67#$1c#$87#$b1;

procedure IncSequence;
begin
  move(Sequence[1],intSequence,SizeOF(Sequence));
  inc(intSequence);
  move(intSequence,Sequence[1],SizeOf(test));
end;

Whith this procedure, only the second byte increment. The result is:

#$67#$1D#$87#$B1  
#$67#$1E#$87#$B1 
#$67#$1F#$87#$B1 

Thanks

Answer 1

You could also do this by creating a "variant record" and just using Inc();

type
  testrec = record
    case Byte of
      0: (data: array[0..3] of AnsiChar);
      1: (intSequence: Integer);
  end;
var
  Sequence: testrec;
begin
  Sequence.data = #$b1#$87#$1c#$67; // reversed because of "endian-ness"
  Inc(Sequence.intSequence);
end;

In this case, the data and intSequence fields "overlay" each other in memory, so any writes to one field will immediately reflect in the other.