/* $OpenBSD: fifo_defs.h,v 1.4 2023/10/17 09:52:08 nicm Exp $ */

/****************************************************************************
 * Copyright 2020 Thomas E. Dickey                                          *
 * Copyright 1998-2012,2016 Free Software Foundation, Inc.                  *
 *                                                                          *
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 * 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               *
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/****************************************************************************
 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
 ****************************************************************************/

/*
 * Common macros for lib_getch.c, lib_ungetch.c
 *
 * $Id: fifo_defs.h,v 1.4 2023/10/17 09:52:08 nicm Exp $
 */

#ifndef FIFO_DEFS_H
#define FIFO_DEFS_H 1

#define head    sp->_fifohead
#define tail    sp->_fifotail
/* peek points to next uninterpreted character */
#define peek    sp->_fifopeek

#define h_inc() { \
            (head >= FIFO_SIZE-1) \
                ? head = 0 \
                : head++; \
            if (head == tail) \
                head = -1, tail = 0; \
        }
#define h_dec() { \
            (head <= 0) \
                ? head = FIFO_SIZE-1 \
                : head--; \
            if (head == tail) \
                tail = -1; \
        }
#define t_inc() { \
            (tail >= FIFO_SIZE-1) \
                ? tail = 0 \
                : tail++; \
            if (tail == head) \
                tail = -1; \
            }
#define t_dec() { \
            (tail <= 0) \
                ? tail = FIFO_SIZE-1 \
                : tail--; \
            if (head == tail) \
                fifo_clear(sp); \
            }
#define p_inc() { \
            (peek >= FIFO_SIZE-1) \
                ? peek = 0 \
                : peek++; \
            }

#define cooked_key_in_fifo()    ((head >= 0) && (peek != head))
#define raw_key_in_fifo()       ((head >= 0) && (peek != tail))

#endif /* FIFO_DEFS_H */