unit Unit2;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Math, Vcl.FileCtrl, StrUtils;

type
  TForm2 = class(TForm)
    Label1: TLabel;
    Memo1: TMemo;
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form2: TForm2;

implementation

{$R *.dfm}

function MinimizeNameFast(const Filename: string; const Canvas: TCanvas; const MaxLen: Integer;
  const Step: string = '...'): string;
var
  Return: string;
  S: TSize;
  I, LenStr, Offset, ResultLen: Integer;
  StrCurr: PChar;
begin
  Result := '';
  if Canvas.TextWidth(Filename) <= MaxLen then
    Exit(Filename);

  I := Pos(':', Filename);

  case Filename[I + 1] of
    '\', '/': Inc(I);
  end;

  Offset := Length(Step);

  ResultLen := I + Offset;

  SetLength(Return, ResultLen);

  ResultLen := 1;
  if I > 0 then
  begin
    Move(Filename[1], Return[ResultLen], I * SizeOf(Char));
    Inc(ResultLen, I);
  end;

  Move(Step[1], Return[ResultLen], Offset * SizeOf(Char));
  Inc(ResultLen, Offset);

  LenStr := Length(Filename);
  I := LenStr;

  StrCurr := PChar(Pointer(Filename));
  Inc(StrCurr, LenStr);

  repeat
    case StrCurr^ of
      '\', '/':
        begin
          Offset := LenStr - I;
          SetLength(Return, ResultLen + Offset - 1);
          Move(StrCurr^, Return[ResultLen], Offset * SizeOf(Char));

          if Canvas.TextWidth(Return) > MaxLen then
            if Result = '' then
              Exit(Return)
            else
              Exit;
          Result := Return;
        end;
    end;
    Dec(I);
    Dec(StrCurr);
  until Cardinal(Pointer(Filename)) >= Cardinal(StrCurr);

  Result := Filename;
end;

const
  Str: array [0 .. 6] of string = ('ger.exe', 'c:\DIR11111\DIR2\DIR3\DIR4\DIR5\DIR6\DIR7\5675.exe',
    'g:\erhrthrthrth\rthy5r6y95\erpogkeokgr\erger.exe',
    't:\095t904i59045derghrth\erthr45hy45y\4.exe',
    '\rthrtyrtjrj\rthrthrthrthrth\45y45y45y45y45y.exe',
    'ioptrhr\rthjtyjtyjtyj\4otykotyj\ftrjtyjtyjty.exe',
    'rthgtyjtyjtdyjtyjtyjtkry67ki6ryjktyyukyfukytukyukyfrkyukyukyukyukrth.exe');

procedure TForm2.FormCreate(Sender: TObject);
  procedure TestMinimizeNameFast(T: TCanvas; C: Integer);
  var
    Fr, T1, T2: Int64;
    Dt: Extended;
    I: Integer;
    S: string;
  begin
    QueryPerformanceFrequency(Fr);
    QueryPerformanceCounter(T1);
    for I := 0 to C do
      for S in Str do
        MinimizeNameFast(S, T, RandomRange(80, 160));
    QueryPerformanceCounter(T2);
    Dt := (T2 - T1) / Fr;
    Memo1.Lines.Add('Fast Время выполнения в секундах: ' + FloatToStr(Dt));
  end;

  procedure TestMinimizeName(T: TCanvas; C: Integer);
  var
    Fr, T1, T2: Int64;
    Dt: Extended;
    I: Integer;
    S: string;
  begin
    QueryPerformanceFrequency(Fr);
    QueryPerformanceCounter(T1);
    for I := 0 to C do
      for S in Str do
        MinimizeName(S, T, RandomRange(80, 160));
    QueryPerformanceCounter(T2);
    Dt := (T2 - T1) / Fr;
    Memo1.Lines.Add('turtle Время выполнения в секундах: ' + FloatToStr(Dt));
  end;

var
  S, R1, R2, Res: string;
  T: TCanvas;
  I, R: Integer;
begin
  Memo1.Lines.Clear;
  Memo1.ScrollBars := SsBoth;
  T := Label1.Canvas;
  TestMinimizeNameFast(T, 1000000);
  TestMinimizeName(T, 1000000);

  for R := 0 to 5 do
  begin
    Memo1.Lines.Add('-------------------');
    for S in Str do
    begin
      I := RandomRange(80, 160);
      R1 := MinimizeNameFast(S, T, I);
      R2 := MinimizeName(S, T, I);

      Res := '[' + T.TextWidth(R1).ToString;
      Res := Res + ' - ' + T.TextWidth(R2).ToString;
      Res := Res + '] max (' + I.ToString + ') "' + R1 + '" > - < "' + R2 + '"';

      Memo1.Lines.Add(Res);
    end;
  end;
end;

end.

Unit2.pas.88: end;
005D366E 33C0             xor eax,eax
005D3670 5A               pop edx
005D3671 59               pop ecx
005D3672 59               pop ecx
005D3673 648910           mov fs:[eax],edx
005D3676 688B365D00       push $005d368b
005D367B 8D45FC           lea eax,[ebp-$04] // Тут он чистит const Filename: string; 
005D367E E81566E3FF       call @UStrClr
005D3683 C3               ret 
005D3684 E92B5CE3FF       jmp @HandleFinally
005D3689 EBF0             jmp $005d367b
005D368B 5F               pop edi
005D368C 5E               pop esi
005D368D 5B               pop ebx
005D368E 8BE5             mov esp,ebp
005D3690 5D               pop ebp
005D3691 C20800           ret $0008