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/* $OpenBSD: ring.h,v 1.9 2014/07/20 08:12:46 guenther Exp $ */
/* $NetBSD: ring.h,v 1.5 1996/02/28 21:04:09 thorpej Exp $ */
/*
* 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. 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.
*
* from: @(#)ring.h 8.1 (Berkeley) 6/6/93
*/
/*
* 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 */
unsigned char *supply; /* where data comes in to */
unsigned char *bottom; /* lowest address in buffer */
unsigned char *top; /* highest address+1 in buffer */
unsigned char *mark; /* marker (user defined) */
int size; /* size in bytes of buffer */
unsigned long consumetime; /* help us keep straight full, empty, etc. */
unsigned long supplytime;
} Ring;
/* Here are some functions and macros to deal with the ring buffer */
/* Initialization routine */
void ring_init(Ring *ring, unsigned char *buffer, int size);
/* Data movement routines */
void ring_supply_data(Ring *ring, unsigned char *buffer, int count);
/* Buffer state transition routines */
void ring_supplied(Ring *ring, int count);
void ring_consumed(Ring *ring, int count);
/* Buffer state query routines */
int ring_empty_count(Ring *ring);
int ring_empty_consecutive(Ring *ring);
int ring_full_count(Ring *ring);
int ring_full_consecutive(Ring *ring);
/* Buffer urgent data handling */
void ring_clear_mark(Ring *);
void ring_mark(Ring *);
int ring_at_mark(Ring *);
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