Code:

function TextToTime(S: string): Integer;

var

  p, i: Integer;

  Sh, Sm, Ss: string;

begin

  Sh := '';

  SM := '';

  SS := '';

  i  := 1;

  p  := 0;

  while i do

  begin

    if (s[i] <> ':') then

    begin

      case P of

        0: SH := Sh + s[i];

        1: SM := SM + S[i];

        2: SS := SS + S[i];

      end;

    end

    else

      Inc(p);

    Inc(i);

  end;

  try

    Result := (StrToInt(SH) * 3600) + (StrToInt(SM) * 60) + (StrToInt(SS))

    except

      Result := 0;

  end;

end;

function TimeToText(T: Integer): string;

var

  H, M, S: string;

  ZH, ZM, ZS: Integer;

begin

  ZH := T div 3600;

  ZM := T div 60 - ZH * 60;

  ZS := T - (ZH * 3600 + ZM * 60);

  if ZH then H := '0' + IntToStr(ZH)

  else

    H := IntToStr(ZH);

  if ZM then M := '0' + IntToStr(ZM)

  else

    M := IntToStr(ZM);

  if ZS then S := '0' + IntToStr(ZS)

  else

    S := IntToStr(ZS);

  Result := H + ':' + M + ':' + S;

end;