unit readkey;

interface

uses
  Windows, SysUtils;

  function ReadKey : char;


implementation

function ReadKey : char;
var _hin : integer;
    kbdmode : TKbdMode;
begin
   Result := char(0);

   _hin := GetStdHandle(STD_INPUT_HANDLE);
    if (GetConsoleMode(_hin, kbdmode) != TRUE) then exit;
        return -1;

    if (SetConsoleMode(_hin, 0 ) != TRUE)
    {
        return -1;
    }

    /* Get keyboard events until a recognizable one appears.
     */
    for (;;)
    {
        if (ReadConsoleInput(_hin, &inp, 1, &nread) != TRUE)
        {
            c = -1;
            break;
        }
        else if ((inp.EventType==KEY_EVENT) && inp.Event.KeyEvent.bKeyDown)
        {
            keycode = inp.Event.KeyEvent.wVirtualKeyCode;
            state   = inp.Event.KeyEvent.dwControlKeyState;

            /*
             * Test for the Win95 anomaly where the NumericPad '.' button
             * (with NumLock on) returns a 0x2E (VK_DELETE) when it should
             * return a 0x6E (VK_DECIMAL) like NT does.
             */
            if ((state & NUMLOCK_ON) && (keycode == VK_DELETE))
                keycode = VK_DECIMAL;

            /* Look up the virtual keycode in the table.  Ignore
             * unrecognized keys.
             */
            for (k = &kbdtab[0]; keycode != k->keycode && k->keycode != -1; k++)
                ;
#if defined(_MBCS)
            if (k->keycode == -1 && !inp.Event.KeyEvent.uChar.AsciiChar)    /* value not in table */
                continue;
#else
            if (k->keycode == -1)       /* value not in table */
                continue;
#endif

            /* Check the state of the shift keys.  ALT has highest
             * priority, followed by Control, followed by Shift.
             * Select the appropriate table entry based on shift state.
             */
            if (state & (RIGHT_ALT_PRESSED | LEFT_ALT_PRESSED))
                c = k->alt;
            else if (state & (RIGHT_CTRL_PRESSED | LEFT_CTRL_PRESSED))
                c = k->ctrl;
            else if (state & SHIFT_PRESSED)
                c = k->shift;
            else
            {
                /* If it is a letter key, use the ASCII value supplied
                 * by NT to take into account the CapsLock state.
                 */
                if (keycode >= 'A' && keycode <= 'Z')
                    c = inp.Event.KeyEvent.uChar.AsciiChar;
                else
                    c = k->normal;
            }
            if (c == -1)
                continue;               /* no BIOS equivalent */

            /* If it is an extended key, save the key value and
             * return 0.  The next time we're called, we'll return
             * the key value.
             */
            if (ISEXT(c))
            {
                _cextend = EXTVAL(c);
                c = 0;
            }
            break;
        }
    }

    /* Change the keyboard back to its original mode.
     */
    if (SetConsoleMode(_hin, kbdmode) != TRUE)
    {
        return -1;
    }

    return c;
end;


end.