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/****************************************************************************
 * Copyright (c) 1998-2002,2007 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    *
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
 * 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("$Id: lib_ungetch.c,v 1.9 2007/09/29 21:49:56 tom Exp $")

#include <fifo_defs.h>

#ifdef TRACE
NCURSES_EXPORT(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, _tracechar(SP->_fifo[i])));
}
#endif /* TRACE */

NCURSES_EXPORT(int)
ungetch(int ch)
{
    T((T_CALLED("ungetch(%s)"), _tracechar(ch)));

    if (tail == -1)
	returnCode(ERR);
    if (head == -1) {
	head = 0;
	t_inc()
	    peek = tail;	/* no raw keys */
    } else
	h_dec();

    SP->_fifo[head] = ch;
    T(("ungetch %s ok", _tracechar(ch)));
#ifdef TRACE
    if (USE_TRACEF(TRACE_IEVENT)) {
	_nc_fifo_dump();
	_nc_unlock_global(tracef);
    }
#endif
    returnCode(OK);
}