[SOLVED] Improvement of function TCustomApplication.FindOptionIndex

[lagprogramming]

packages/fcl-base/src/custapp.pp has

Code: Pascal  [Select][+][-]

1. function TCustomApplication.FindOptionIndex(const S: String;
2.   var Longopt: Boolean; StartAt : Integer = -1): Integer;
3.  
4. Var
5.   SO,O : String;
6.   I,P : Integer;
7.  
8. begin
9.   If Not CaseSensitiveOptions then
10.     SO:=UpperCase(S)
11.   else
12.     SO:=S;
13.   Result:=-1;
14.   I:=StartAt;
15.   if (I=-1) then
16.     I:=ParamCount;
17.   While (Result=-1) and (I>0) do
18.     begin
19.     O:=Params[i];
20.     // - must be seen as an option value
21.     If (Length(O)>1) and (O[1]=FOptionChar) then
22.       begin
23.       Delete(O,1,1);
24.       LongOpt:=(Length(O)>0) and (O[1]=FOptionChar);
25.       If LongOpt then
26.         begin
27.         Delete(O,1,1);
28.         P:=Pos('=',O);
29.         If (P<>0) then
30.           O:=Copy(O,1,P-1);
31.         end;
32.       If Not CaseSensitiveOptions then
33.         O:=UpperCase(O);
34.       If (O=SO) then
35.         Result:=i;
36.       end;
37.     Dec(i);
38.     end;
39. end;

1/2 The following lines contain a useless condition

Code: Pascal  [Select][+][-]

1.     If (Length(O)>1) and (O[1]=FOptionChar) then
2.       begin
3.       Delete(O,1,1);
4.       LongOpt:=(Length(O)>0) and (O[1]=FOptionChar);

The condition (Length(O)>0) is always true because before deleting the first character using "Delete(O,1,1);" the length of variable O was at least 2(due to the "If (Length(O)>1)" condition).
So, "LongOpt:=(Length(O)>0) and (O[1]=FOptionChar);" has been replaced with "LongOpt:=(O[1]=FOptionChar);".

2/2 After that, "If (P<>0) then O:=Copy(O,1,P-1);" has been replaced with "If (P<>0) then SetLength(O,P-1);".

Here is a patch

[AlexTP]

posted to https://gitlab.com/freepascal.org/fpc/source/-/issues/40663 .

[Thaddy]

You know I like micro optimizations, but in this case (Assuming {$B-} state) it does not seem to matter in the generated assembler. Although your logic is correct.