How can I search faster for name/value pairs in a Delphi TStringList?

Question

I implemented language translation in an application by putting all strings at runtime in a TStringList with:

procedure PopulateStringList;
begin  
  EnglishStri         


        

Answer 1

You can also use a CLASS HELPER to re-program the "IndexOfName" function:

TYPE
  TStringsHelper = CLASS HELPER FOR TStrings
                     FUNCTION IndexOfName(CONST Name : STRING) : INTEGER;
                   END;

FUNCTION TStringsHelper.IndexOfName(CONST Name : STRING) : INTEGER;
  VAR
    SL  : TStringList ABSOLUTE Self;
    S,T : STRING;
    I   : INTEGER;

  BEGIN
    IF (Self IS TStringList) AND SL.Sorted THEN BEGIN
      S:=Name+NameValueSeparator;
      IF SL.Find(S,I) THEN
        Result:=I
      ELSE IF (I<0) OR (I>=Count) THEN
        Result:=-1
      ELSE BEGIN
        T:=SL[I];
        IF CompareStrings(COPY(T,1,LENGTH(S)),S)=0 THEN Result:=I ELSE Result:=-1
      END;
      EXIT
    END;
    Result:=INHERITED IndexOfName(Name)
  END;

(or implement it in a descendant TStrings class if you dislike CLASS HELPERs or don't have them in your Delphi version).

This will use a binary search on a sorted TStringList and a sequential search on other TStrings classes.