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/*

 * Copyright (c) 1988, 1993

 *      The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *      This product includes software developed by the University of

 *      California, Berkeley and its contributors.

 * 4. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 *

 *      @(#)ring.h      8.1 (Berkeley) 6/6/93

 */

#ifndef __RING_H__

#define __RING_H__

#if defined(P)

# undef P

#endif

#if defined(__STDC__) || defined(LINT_ARGS)

# define        P(x)    x

#else

# define        P(x)    ()

#endif

/*

 * This defines a structure for a ring buffer.

 *

 * The circular buffer has two parts:

 *(((

 *      full:   [consume, supply)

 *      empty:  [supply, consume)

 *]]]

 *

 */

typedef struct {

    unsigned char       *consume,       /* where data comes out of */

                        *supply,        /* where data comes in to */

                        *bottom,        /* lowest address in buffer */

                        *top,           /* highest address+1 in buffer */

                        *mark;          /* marker (user defined) */

    int         size;           /* size in bytes of buffer */

    u_long      consumetime,    /* help us keep straight full, empty, etc. */

                supplytime;

} Ring;

/* Here are some functions and macros to deal with the ring buffer */

/* Initialization routine */

extern int

        ring_init P((Ring *ring, unsigned char *buffer, int count));

/* Data movement routines */

extern void

        ring_supply_data P((Ring *ring, unsigned char *buffer, int count));

#ifdef notdef

extern void

        ring_consume_data P((Ring *ring, unsigned char *buffer, int count));

#endif

/* Buffer state transition routines */

extern void

        ring_supplied P((Ring *ring, int count)),

        ring_consumed P((Ring *ring, int count));

/* Buffer state query routines */

extern int

        ring_empty_count P((Ring *ring)),

        ring_empty_consecutive P((Ring *ring)),

        ring_full_count P((Ring *ring)),

        ring_full_consecutive P((Ring *ring));

extern void

    ring_clear_mark(),

    ring_mark();

#endif