text: /*	$OpenBSD: lib_ungetch.c,v 1.2 1998/07/23 21:19:46 millert Exp $	*/
  
  /****************************************************************************
   * Copyright (c) 1998 Free Software Foundation, Inc.                        *
   *                                                                          *
   * Permission is hereby granted, free of charge, to any person obtaining a  *
   * copy of this software and associated documentation files (the            *
   * "Software"), to deal in the Software without restriction, including      *
   * without limitation the rights to use, copy, modify, merge, publish,      *
   * distribute, distribute with modifications, sublicense, and/or sell       *
   * copies of the Software, and to permit persons to whom the Software is    *
   * furnished to do so, subject to the following conditions:                 *
   *                                                                          *
   * The above copyright notice and this permission notice shall be included  *
   * in all copies or substantial portions of the Software.                   *
   *                                                                          *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
   * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
   * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
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   * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
   *                                                                          *
   * Except as contained in this notice, the name(s) of the above copyright   *
   * holders shall not be used in advertising or otherwise to promote the     *
   * sale, use or other dealings in this Software without prior written       *
   * authorization.                                                           *
   ****************************************************************************/
  
  /****************************************************************************
   *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
   *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
   ****************************************************************************/
  
  /*
  **	lib_ungetch.c
  **
  **	The routine ungetch().
  **
  */
  
  #include <curses.priv.h>
  
  MODULE_ID("$From: lib_ungetch.c,v 1.2 1998/02/11 12:13:56 tom Exp $")
  
  #include <fifo_defs.h>
  
  #ifdef TRACE
  void _nc_fifo_dump(void)
  {
  int i;
  	T(("head = %d, tail = %d, peek = %d", head, tail, peek));
  	for (i = 0; i < 10; i++)
  		T(("char %d = %s", i, _trace_key(SP->_fifo[i])));
  }
  #endif /* TRACE */
  
  int ungetch(int ch)
  {
  	if (tail == -1)
  		return ERR;
  	if (head == -1) {
  		head = 0;
  		t_inc()
  		peek = tail; /* no raw keys */
  	} else
  		h_dec();
  
  	SP->_fifo[head] = ch;
  	T(("ungetch %#x ok", ch));
  #ifdef TRACE
  	if (_nc_tracing & TRACE_IEVENT) _nc_fifo_dump();
  #endif
  	return OK;
  }
  