text: /* Public Domain Curses */
  
  #include <curspriv.h>
  
  /*man-start**************************************************************
  
  getch
  -----
  
  ### Synopsis
  
      int getch(void);
      int wgetch(WINDOW *win);
      int mvgetch(int y, int x);
      int mvwgetch(WINDOW *win, int y, int x);
      int ungetch(int ch);
      int flushinp(void);
  
      int get_wch(wint_t *wch);
      int wget_wch(WINDOW *win, wint_t *wch);
      int mvget_wch(int y, int x, wint_t *wch);
      int mvwget_wch(WINDOW *win, int y, int x, wint_t *wch);
      int unget_wch(const wchar_t wch);
  
      unsigned long PDC_get_key_modifiers(void);
      int PDC_save_key_modifiers(bool flag);
      int PDC_return_key_modifiers(bool flag);
  
  ### Description
  
     With the getch(), wgetch(), mvgetch(), and mvwgetch() functions,
     a character is read from the terminal associated with the window.
     In nodelay mode, if there is no input waiting, the value ERR is
     returned. In delay mode, the program will hang until the system
     passes text through to the program. Depending on the setting of
     cbreak(), this will be after one character or after the first
     newline.  Unless noecho() has been set, the character will also
     be echoed into the designated window.
  
     If keypad() is TRUE, and a function key is pressed, the token for
     that function key will be returned instead of the raw characters.
     Possible function keys are defined in <curses.h> with integers
     beginning with 0401, whose names begin with KEY_.
  
     If nodelay(win, TRUE) has been called on the window and no input
     is waiting, the value ERR is returned.
  
     ungetch() places ch back onto the input queue to be returned by
     the next call to wgetch().
  
     flushinp() throws away any type-ahead that has been typed by the
     user and has not yet been read by the program.
  
     PDC_get_key_modifiers() returns the keyboard modifiers (shift,
     control, alt, numlock) effective at the time of the last getch()
     call, if PDC_save_key_modifiers(TRUE) has been called before the
     getch(). Use the macros PDC_KEY_MODIFIER_* to determine which
     modifier(s) were set. PDC_return_key_modifiers() tells getch()
     to return modifier keys pressed alone as keystrokes (KEY_ALT_L,
     etc.). These may not work on all platforms.
  
     NOTE: getch() and ungetch() are implemented as macros, to avoid
     conflict with many DOS compiler's runtime libraries.
  
  ### Return Value
  
     These functions return ERR or the value of the character, meta
     character or function key token.
  
  ### Portability
                               X/Open    BSD    SYS V
      getch                       Y       Y       Y
      wgetch                      Y       Y       Y
      mvgetch                     Y       Y       Y
      mvwgetch                    Y       Y       Y
      ungetch                     Y       Y       Y
      flushinp                    Y       Y       Y
      get_wch                     Y
      wget_wch                    Y
      mvget_wch                   Y
      mvwget_wch                  Y
      unget_wch                   Y
      PDC_get_key_modifiers       -       -       -
  
  **man-end****************************************************************/
  
  #define _INBUFSIZ   512 /* size of terminal input buffer */
  #define NUNGETCH    256 /* max # chars to ungetch() */
  
  static int c_pindex = 0;    /* putter index */
  static int c_gindex = 1;    /* getter index */
  static int c_ungind = 0;    /* ungetch() push index */
  static int c_ungch[NUNGETCH];   /* array of ungotten chars */
  
  static int _mouse_key(WINDOW *win)
  {
      int i, key = KEY_MOUSE;
      unsigned long mbe = SP->_trap_mbe;
  
      /* Filter unwanted mouse events */
  
      for (i = 0; i < 3; i++)
      {
          if (pdc_mouse_status.changes & (1 << i))
          {
              int shf = i * 5;
              short button = pdc_mouse_status.button[i] & BUTTON_ACTION_MASK;
  
              if (   (!(mbe & (BUTTON1_PRESSED << shf)) &&
                      (button == BUTTON_PRESSED))
  
                  || (!(mbe & (BUTTON1_CLICKED << shf)) &&
                      (button == BUTTON_CLICKED))
  
                  || (!(mbe & (BUTTON1_DOUBLE_CLICKED << shf)) &&
                      (button == BUTTON_DOUBLE_CLICKED))
  
                          /* added triple clicks 2011 jun 4: BJG */
                  || (!(mbe & (BUTTON1_TRIPLE_CLICKED << shf)) &&
                      (button == BUTTON_TRIPLE_CLICKED))
  
                  || (!(mbe & (BUTTON1_MOVED << shf)) &&
                      (button == BUTTON_MOVED))
  
                  || (!(mbe & (BUTTON1_RELEASED << shf)) &&
                      (button == BUTTON_RELEASED))
              )
                  pdc_mouse_status.changes ^= (1 << i);
          }
      }
  
      if (pdc_mouse_status.changes & PDC_MOUSE_MOVED)
      {
          if (!(mbe & (BUTTON1_MOVED|BUTTON2_MOVED|BUTTON3_MOVED)))
              pdc_mouse_status.changes ^= PDC_MOUSE_MOVED;
      }
  
      if (pdc_mouse_status.changes &
          (PDC_MOUSE_WHEEL_UP|PDC_MOUSE_WHEEL_DOWN))
      {
          if (!(mbe & MOUSE_WHEEL_SCROLL))
              pdc_mouse_status.changes &=
                  ~(PDC_MOUSE_WHEEL_UP|PDC_MOUSE_WHEEL_DOWN);
      }
  
      if (!pdc_mouse_status.changes)
          return -1;
  
      /* Check for click in slk area */
  
      i = PDC_mouse_in_slk(pdc_mouse_status.y, pdc_mouse_status.x);
  
      if (i)
      {
          if (pdc_mouse_status.button[0] & (BUTTON_PRESSED|BUTTON_CLICKED))
              key = KEY_F(i);
          else
              key = -1;
      }
  
      return key;
  }
  
  int wgetch(WINDOW *win)
  {
      static int buffer[_INBUFSIZ];   /* character buffer */
      int key, waitcount;
  
      PDC_LOG(("wgetch() - called\n"));
  
      if (!win)
          return ERR;
  
      waitcount = 0;
  
       /* set the number of 1/20th second napms() calls */
  
      if (SP->delaytenths)
          waitcount = 2 * SP->delaytenths;
      else
          if (win->_delayms)
          {
              /* Can't really do millisecond intervals, so delay in
                 1/20ths of a second (50ms) */
  
              waitcount = win->_delayms / 50;
              if (!waitcount)
                  waitcount = 1;
          }
  
      /* refresh window when wgetch is called if there have been changes
         to it and it is not a pad */
  
      if (!(win->_flags & _PAD) && ((!win->_leaveit &&
           (win->_begx + win->_curx != SP->curscol ||
            win->_begy + win->_cury != SP->cursrow)) || is_wintouched(win)))
          wrefresh(win);
  
      /* if ungotten char exists, remove and return it */
  
      if (c_ungind)
          return c_ungch[--c_ungind];
  
      /* if normal and data in buffer */
  
      if ((!SP->raw_inp && !SP->cbreak) && (c_gindex < c_pindex))
          return buffer[c_gindex++];
  
      /* prepare to buffer data */
  
      c_pindex = 0;
      c_gindex = 0;
  
      /* to get here, no keys are buffered. go and get one. */
  
      for (;;)            /* loop for any buffering */
      {
          /* is there a keystroke ready? */
  
          if (!PDC_check_key())
          {
              /* if not, handle timeout() and halfdelay() */
  
              if (SP->delaytenths || win->_delayms)
              {
                  if (!waitcount)
                      return ERR;
  
                  waitcount--;
              }
              else
                  if (win->_nodelay)
                      return ERR;
  
              napms(50);  /* sleep for 1/20th second */
              continue;   /* then check again */
          }
  
          /* if there is, fetch it */
  
          key = PDC_get_key();
  
          if (SP->key_code)
          {
              /* filter special keys if not in keypad mode */
  
              if (!win->_use_keypad)
                  key = -1;
  
              /* filter mouse events; translate mouse clicks in the slk
                 area to function keys */
  
              else if (key == KEY_MOUSE)
                  key = _mouse_key(win);
          }
  
          /* unwanted key? loop back */
  
          if (key == -1)
              continue;
  
          /* translate CR */
  
          if (key == '\r' && SP->autocr && !SP->raw_inp)
              key = '\n';
  
          /* if echo is enabled */
  
          if (SP->echo && !SP->key_code)
          {
              waddch(win, key);
              wrefresh(win);
          }
  
          /* if no buffering */
  
          if (SP->raw_inp || SP->cbreak)
              return key;
  
          /* if no overflow, put data in buffer */
  
          if (key == '\b')
          {
              if (c_pindex > c_gindex)
                  c_pindex--;
          }
          else
              if (c_pindex < _INBUFSIZ - 2)
                  buffer[c_pindex++] = key;
  
          /* if we got a line */
  
          if (key == '\n' || key == '\r')
              return buffer[c_gindex++];
      }
  }
  
  int mvgetch(int y, int x)
  {
      PDC_LOG(("mvgetch() - called\n"));
  
      if (move(y, x) == ERR)
          return ERR;
  
      return wgetch(stdscr);
  }
  
  int mvwgetch(WINDOW *win, int y, int x)
  {
      PDC_LOG(("mvwgetch() - called\n"));
  
      if (wmove(win, y, x) == ERR)
          return ERR;
  
      return wgetch(win);
  }
  
  int PDC_ungetch(int ch)
  {
      PDC_LOG(("ungetch() - called\n"));
  
      if (c_ungind >= NUNGETCH)   /* pushback stack full */
          return ERR;
  
      c_ungch[c_ungind++] = ch;
  
      return OK;
  }
  
  int flushinp(void)
  {
      PDC_LOG(("flushinp() - called\n"));
  
      PDC_flushinp();
  
      c_gindex = 1;           /* set indices to kill buffer */
      c_pindex = 0;
      c_ungind = 0;           /* clear c_ungch array */
  
      return OK;
  }
  
  unsigned long PDC_get_key_modifiers(void)
  {
      PDC_LOG(("PDC_get_key_modifiers() - called\n"));
  
      return pdc_key_modifiers;
  }
  
  int PDC_save_key_modifiers(bool flag)
  {
      PDC_LOG(("PDC_save_key_modifiers() - called\n"));
  
      SP->save_key_modifiers = flag;
      return OK;
  }
  
  int PDC_return_key_modifiers(bool flag)
  {
      PDC_LOG(("PDC_return_key_modifiers() - called\n"));
  
      SP->return_key_modifiers = flag;
      return PDC_modifiers_set();
  }
  
  #ifdef PDC_WIDE
  int wget_wch(WINDOW *win, wint_t *wch)
  {
      int key;
  
      PDC_LOG(("wget_wch() - called\n"));
  
      if (!wch)
          return ERR;
  
      key = wgetch(win);
  
      if (key == ERR)
          return ERR;
  
      *wch = key;
  
      return SP->key_code ? KEY_CODE_YES : OK;
  }
  
  int get_wch(wint_t *wch)
  {
      PDC_LOG(("get_wch() - called\n"));
  
      return wget_wch(stdscr, wch);
  }
  
  int mvget_wch(int y, int x, wint_t *wch)
  {
      PDC_LOG(("mvget_wch() - called\n"));
  
      if (move(y, x) == ERR)
          return ERR;
  
      return wget_wch(stdscr, wch);
  }
  
  int mvwget_wch(WINDOW *win, int y, int x, wint_t *wch)
  {
      PDC_LOG(("mvwget_wch() - called\n"));
  
      if (wmove(win, y, x) == ERR)
          return ERR;
  
      return wget_wch(win, wch);
  }
  
  int unget_wch(const wchar_t wch)
  {
      return PDC_ungetch(wch);
  }
  #endif
  