> On Apr 25, 2018, at 12:59 PM, Sven Barth via fpc-pascal
> <fpc-pascal@lists.freepascal.org> wrote:
>
> The memory model of classes in Object Pascal is heap based. Changing that is
> asking for trouble and I for one don't even want to fiddle around with that,
> because I don't see any real benefit in it (and yes I daily work with C++)
> that couldn't also be solved with a working ARC system.
>
Just for fun here’s that same code from the previous post but with the keyword
added. :) It’s really a good example because this is the same thing we do over
and over again every day so it’s a perfect candidate for a simple compiler
optimization. We save a block of code, not forgetting to call free and 2
pointers from GemMem that wasted CPU and got us closer to a fragmented heap.
It’s minor but it’s saves minor amounts of time and CPU cycles, both of which
really add up over the lifetime of a program.
The programer in this case knows with 100% certainty they don’t need 2 pointers
from GetMem but Pascal forces us anyways, and then makes us clean up the mess
we didn’t need to make in the first place.
PS. I’m aware those 2 functions may actually raise exceptions but pretend they
didn’t and this was just common memory management we do every day.
new code:
function TBlowFishCripto.Encrypt(const Value: string): string;
var
en: TBlowFishEncryptStream; stackalias;
stream: TStringStream; stackalias;
begin
if length(Value) = 0 then
begin
Result := '';
Exit;
end;
stream := TStringStream.Create('');
en := TBlowFishEncryptStream.Create(FKey, stream);
en.Write(Value[1], Length(Value));
Result := stream.DataString;
end;
original code:
function TBlowFishCripto.Encrypt(const Value: string): string;
var
en: TBlowFishEncryptStream;
stream: TStringStream;
begin
if length(Value) = 0 then
begin
Result := '';
Exit;
end;
try
stream := TStringStream.Create('');
en := TBlowFishEncryptStream.Create(FKey, stream);
en.Write(Value[1], Length(Value));
Result := stream.DataString;
finally
FreeAndNil(en);
FreeAndNil(stream);
end;
end;
Regards,
Ryan Joseph
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