i := Pos(#0'Фыва'#0'Пролд', #0#0'Йцукен'#0'Фыва'#0'НеПролд'#0'Фыва'#0'Пролд');
  //                          1 2 345678 9  0123 14 5678901 22
  ShowMessage(IntToStr(i)); // возврашает 22

type Str32 = String; //WideString;
//т.к. мне нужны были функции, раборающие с widestring.

procedure Insert(const Source: Str32; var Str: Str32; Index: Longint);
var
  StrLength, SourceLength: Longint;
begin
  StrLength := Length(Str);
  SourceLength := Length(Source);
  SetLength(Str, StrLength + SourceLength);
  Move(Str[Index], Str[Index + SourceLength], (StrLength - Index + 1) * SizeOf(Char));
  Move(Source[1], Str[Index], SourceLength * SizeOf(Char));
end;

procedure Delete(var Str: Str32; Index, Count: Longint);
var
  StrLength: Longint;
begin
  {S := Copy(S, 1, Index) + Source + Copy(S, Index + 1, Length(S) - Index)}

  StrLength := Length(Str);
  Move(Str[Index + Count], Str[Index], (StrLength - Count - Index + 1) * SizeOf(Char));
  SetLength(Str, StrLength - Count);
end;

function ComparePString(Str1: Pointer; Str1Length: Longint; Str2: Pointer;
  Str2Length: Longint; CaseSensitive: Boolean = False): Longint;
const
  _FlagCase: array[Boolean] of Longint = (NORM_IGNORECASE, 0);
  CompareResult: array[0..2] of Longint = (-1, 0, 1);
begin
  Result :=
    CompareResult[CompareString(LOCALE_USER_DEFAULT,
      _FlagCase[CaseSensitive], Str1, Str1Length, Str2, Str2Length) - 1]
end;

function CompareString(const Str1, Str2: Str32;
  CaseSensitive: Boolean = False): Longint;
begin
  Result := ComparePString(Pointer(Str1), Length(Str1), Pointer(Str2), Length(Str2), CaseSensitive);
end;

function Pos(const SubStr, Str: Str32; FromPos: Integer = 0; CaseSensitive: Boolean = True): Longint;
var
  Bool: Boolean;
  SubStrLength, StrLength, CurPos: Longint;
  TmpStr: Pointer;
begin
  Bool := False;

  if FromPos < 0 then FromPos := 0;

  CurPos := FromPos;

  if (Str = '') or (SubStr = '') then
  else begin
    SubStrLength := Length(SubStr);
    StrLength := Length(Str);

    if (SubStrLength > StrLength) then
    else begin
      TmpStr := Pointer(Integer(Pointer(Str)) + FromPos);

      while (not Bool) and (CurPos <= StrLength - SubStrLength) do
      begin
        Bool := (ComparePString(Pointer(SubStr), SubStrLength, TmpStr, SubStrLength, CaseSensitive) = 0);
        TmpStr := Pointer(Integer(TmpStr) + 1);
        Inc(CurPos);
      end;
    end
  end;

  if Bool then Result := CurPos else Result := 0;
end;

function StringReplace(const Str, OldPattern, NewPattern: Str32;
  Flags: TReplaceFlags): Str32;
var
  Offset, LengthOldPattern: Integer;
  NewStr: Str32;
begin
  NewStr := Str;
  LengthOldPattern := Length(OldPattern);
  Result := '';

  while NewStr <> '' do
  begin
    Offset := Pos(OldPattern, NewStr, 0, not (rfIgnoreCase in Flags));
    if Offset = 0 then
    begin
      Result := Result + NewStr;
      Break;
    end;
    Result := Result + Copy(NewStr, 1, Offset - 1) + NewPattern;
    Delete(NewStr, 1, Offset + LengthOldPattern - 1);
    if not (rfReplaceAll in Flags) then
    begin
      Result := Result + NewStr;
      Break;
    end;
  end;
end;