[fpc-pascal] string concatenation speed

[Marc Santhoff]

Am Dienstag, den 21.06.2005, 19:21 +0200 schrieb Marco van de Voort:
> > in an application of mine occurs a lot of string separation and
> > re-concatenation. Since it is using masses of ANSI strings this is some
> > performance problem.
> > 
> > The strings get stored and loaded from  TStringList's and concatenated
> > by simply using '+' and separated with the function copy().
> 
> You could try to avoid repeated setlengths. However this would require
> two passes, something like
> 
> tot:=0;
> for i:=0 to strlst.count-1 do  inc(tot,length(strlst[i]));
> setlength(targetstring,tot);
> j:=1;
> for i:=0 to strlst.count-1 do 
>   begin
>     move (targetstring[j],strlst[i]);
>     inc(j,length(strlst[i]));	
>   end;
>  

So in general reserving buffer space and copying all string in and
finally setting the length would be the way to go here, if I understand
correctly.

> Posting more code would help too.

See my other mail.

Thanks,
Marc