------------------------------------------------------
ForkReplaceC_lodsw   -> 00:00:211
ReplaceCharByPChar   -> 00:00:208
TestMy               -> 00:00:207
------------------------------------------------------
ForkReplaceC_lodsw   -> 00:00:212
ReplaceCharByPChar   -> 00:00:207
TestMy               -> 00:00:208
------------------------------------------------------
ForkReplaceC_lodsw   -> 00:00:220
ReplaceCharByPChar   -> 00:00:213
TestMy               -> 00:00:218
------------------------------------------------------
ForkReplaceC_lodsw   -> 00:00:211
ReplaceCharByPChar   -> 00:00:210
TestMy               -> 00:00:208
------------------------------------------------------
ForkReplaceC_lodsw   -> 00:00:212
ReplaceCharByPChar   -> 00:00:212
TestMy               -> 00:00:212

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TCommatFunc = function(s: string): string;

  TForm1 = class(TForm)
    btnCommaToPoint: TButton;
    mmo1: TMemo;
    mmo2: TMemo;
    btnFill: TButton;
    procedure btnCommaToPointClick(Sender: TObject);
    procedure btnFillClick(Sender: TObject);
  private
    function RunFunc(Func: TCommatFunc): TDateTime;

    procedure FillRandomText(const iFactor, iCharCount: Integer);
    { Private declarations }
  public
    { Public declarations }
  end;

const
  CNT_RUN = 1000000;

var
  Form1: TForm1;

implementation

{$R *.DFM}

function ForkReplaceC_lodsw(s: string): string;
const
  COMMA_ = ',';
  DOT_ = '.';
begin
  Result := s;

  asm
    Push  ESI
    Push  EBX

    Mov   EAX,Result
    Or    EAX,EAX
    Jz    @Exit
    Mov   ESI,[EAX]
    Or    ESI,ESI
    Jz    @Exit

    Mov   BH,COMMA_
    Mov   BL,DOT_
    Cmp   AH,BL
    Jz    @Exit

    Mov   ECX,[ESI-4]
    Jecxz @Exit
    push ECX

    shr ECX,1

    Cld
  @Next:
    Lodsw
    Cmp   AH,BH
    Jne   @Skip1
    Mov   [ESI-1],BL
  @Skip1:
    Cmp   AL,BH
    Jne   @Skip
    Mov   [ESI-2],BL
  @Skip:
    Dec   ECX
    Jnz   @Next

    // ------------------------
    pop ECX
    and ECX,2
    jz @Exit
  @Next20:
    Lodsb
    Cmp   AH,BH
    Jne   @Skip20
    Mov   [ESI-1],BL
  @Skip20:
    Dec   ECX
    Jnz   @Next20
  @Exit:
    Pop  EBX
    Pop  ESI

  end;
end;

function ReplaceCharByPChar(const s: string): string;
const
  COMMA_ = ',';
  DOT_ = '.';
var
  P: PChar;
  i: Integer;
begin
  Result := s;
  P := Pointer(Result);
  for i := 0 to Length(s) - 1 do
  begin
    if P^ = COMMA_ then
      P^ := DOT_;
    Inc(P);
  end;
end;

function TestMy(const s: string): string;
const
  COMMA_ = ',';
  DOT_ = '.';
var
  P: PChar;
begin
  Result := s;
  P := Pointer(Result);
  while P^ <> #0 do
  begin
    if P^ = COMMA_ then
      P^ := DOT_;
    Inc(P);
  end;
end;

procedure TForm1.btnCommaToPointClick(Sender: TObject);

  function FormatOutput(const aFuncName: string;
    const iRunTime: TDateTime): string;
  begin
    Result := Format('%-20s -> %s', [aFuncName, FormatDateTime('NN:SS:ZZZ',
      iRunTime)]);
  end;

begin
  mmo1.Lines.Add('------------------------------------------------------');

  mmo1.Lines.Add(FormatOutput('ForkReplaceC_lodsw',
    RunFunc(@ForkReplaceC_lodsw)));

  mmo1.Lines.Add(FormatOutput('ReplaceCharByPChar',
    RunFunc(@ReplaceCharByPChar)));

  mmo1.Lines.Add(FormatOutput('TestMy', RunFunc(@TestMy)));

end;

function TForm1.RunFunc(Func: TCommatFunc): TDateTime;
var
  aStartTime: TDateTime;
  i: Integer;
  s: string;
begin
  s := mmo2.Text;

  aStartTime := Now;

  for i := 0 to 50000 - 1 do
    Func(s);

  Result := Now - aStartTime;
end;

procedure TForm1.FillRandomText(const iFactor, iCharCount: Integer);
var
  i: Integer;
  s: string;
begin
  s := '';

  for i := 0 to iCharCount do
  begin
    if Random(10) > iFactor then
      s := s + ','
    else
      s := s + Chr(40 + Trunc(Random(150)));
  end;

  mmo2.Text := s;

end;

procedure TForm1.btnFillClick(Sender: TObject);
begin
  FillRandomText(10, 5000);
end;

end.