Author: Jonas Bilinkevicius

How to remove white-spaces from a TMemo

Answer:

This would trim a TMemo (multi-line string), discarding any white-space from 
end-of-lines and from end-of-text. The end result is exactly similar to the 
original, without the useless extras, usually left-overs from bad typing habits.
1   
2   function MemoTrimTrail(const aMemo: string): string;
3   var
4     iRead, iWrite, vLastNonWhite, vLastNonSpace: Integer;
5     vChr: Char;
6     vIsSpace, vIsReturn: Boolean;
7   begin
8     if aMemo = '' then
9     begin {empty string}
10      Result := ''; {nothing to do}
11      exit;
12    end;
13    SetLength(Result, Length(aMemo)); {initially, empty string of same length}
14    UniqueString(Result); {make sure we have a separate copy}
15    iWrite := 0; {where characters will be written out}
16    vLastNonWhite := 0; {last non-space, non-return}
17    vLastNonSpace := 0; {last non-space, but could be return}
18    for iRead := 1 to Length(aMemo) do
19    begin
20      vChr := aMemo[iRead]; {pick next char in source}
21      vIsReturn := vChr in [#13, #10]; {CR or LF}
22      vIsSpace := vChr in [#32, #09]; {space or tab}
23      if vIsReturn then
24        iWrite := vLastNonSpace + 1 {skip empty end-of-lines}
25      else
26        Inc(iWrite);
27      Result[iWrite] := vChr; {write char in result-string}
28      if not vIsSpace then
29      begin
30        vLastNonSpace := iWrite; {last non-space, returns are Ok}
31        if not vIsReturn then
32        begin
33          vLastNonWhite := iWrite; {last black-ink character}
34        end;
35      end;
36    end;
37    SetLength(Result, vLastNonWhite); {truncate at last black-ink character}
38  end;