[fpc-devel] tbits.NotBits

[Mattias Gaertner]

On Thu, 13 Apr 2017 11:28:20 +0200
Andrea Mauri <andrea.mauri.75 at gmail.com> wrote:

>[...]
> procedure TBits.Setall;
> var
>     loop : longint;
> begin
>     for loop := 0 to FSize - 1 do
>        FBits^[loop] := 1;

Should be
FBits^[loop] := not cardinal(0);

> end;

Btw, it seems TBits misses an AssignBits(b: TBits).

And maybe an AssignNotBits(b: TBits)


> 2. a Not operator, something like a.NotBits; with no arguments that 
> perform the not operation on the TBIts instance (a[i]:= not a[i]) or 
> something that performs a not operation on the passed TBits, i.e. 
> a.Not(b) that fills a in this way: a[i]:= not b[i];
> 
> procedure TBits.Notbits;
> var
>     n : longint;
>     jj : cardinal;
>     loop : longint;
> begin
>     for loop := 0 to FSize - 1 do
>        FBits^[loop] := not FBits^[loop];
> end;
> 
> or
> 
> procedure TBits.Not(bitset : TBits);

"Not" is a preserved word.


> var
>     n : longint;
>     loop : longint;
> begin
>     if FSize < bitset.getFSize then
>        n := FSize - 1
>     else
>        n := bitset.getFSize - 1;
> 
>     for loop := 0 to n do
>        FBits^[loop] := not bitset.FBits^[loop];
> end;

For consistency with the other SomethingBits methods you must handle all
bits, not just the start.


Mattias