While cleaning up my FTP server code, changing common strings to constants - I pondered which is faster, a constant or a resource string in Free Pascal? The answer makes sense, but I was surprised how much faster...

    Download resource.pas source

Uses
   dxutil_environment;// contains TimeCounter for Windows, Linux and Mac

const
   Str1='This is a constant string';

ResourceString
   Str2='This is a resource string';

Var
   Loop:Longint;
   StartTime:Comp;
   S:String;

Begin
   StartTime:=Trunc(TimeCounter);
   For Loop:=1 to 100000000 do S:=Str1;
   System.Writeln('Constant: ',Trunc(Trunc(TimeCounter)-StartTime));
   StartTime:=Trunc(TimeCounter);
   For Loop:=1 to 100000000 do S:=Str2;
   System.Writeln('Resource: ',Trunc(Trunc(TimeCounter)-StartTime));
   StartTime:=Trunc(TimeCounter);
   For Loop:=1 to 100000000 do S:='This is an inline string';
   System.Writeln('inline: ',Trunc(Trunc(TimeCounter)-StartTime));
end.

     The results on Linux, Constant: 7819 Resource: 4010, due to the design of how a resource is addressed versus a constant, it takes roughly have the time to work with a resource string than a constant. On my Mac Book Pro the results were closer, Constant: 2781 Resource: 1949, but obviously still worth the effort to clean-up some of my high performance products to convert constants to resource strings.

     After writing this page, I went back an added the "inline" to be closer to how must people write their code (not using constants, but inline constant strings). And I found that inline is even a little bit slower than a constant. So, for those of you who want to see a slight improvement in code which does a lot of text output (static text) it is worth revising your code to resource strings. Plus if you ever decide to make your code multi-lingual, it will help you as your can compile in/out different languages. I did this for my DXSock socket suite back in the 90's.

G.E. Ozz Nixon Jr.

Ian Wright
Codemasters