1*c5bc9e33Sguenther /* $OpenBSD: ring.h,v 1.9 2014/07/20 08:12:46 guenther Exp $ */ 24f4c46caSniklas /* $NetBSD: ring.h,v 1.5 1996/02/28 21:04:09 thorpej Exp $ */ 34f4c46caSniklas 4df930be7Sderaadt /* 5df930be7Sderaadt * Copyright (c) 1988, 1993 6df930be7Sderaadt * The Regents of the University of California. All rights reserved. 7df930be7Sderaadt * 8df930be7Sderaadt * Redistribution and use in source and binary forms, with or without 9df930be7Sderaadt * modification, are permitted provided that the following conditions 10df930be7Sderaadt * are met: 11df930be7Sderaadt * 1. Redistributions of source code must retain the above copyright 12df930be7Sderaadt * notice, this list of conditions and the following disclaimer. 13df930be7Sderaadt * 2. Redistributions in binary form must reproduce the above copyright 14df930be7Sderaadt * notice, this list of conditions and the following disclaimer in the 15df930be7Sderaadt * documentation and/or other materials provided with the distribution. 16f75387cbSmillert * 3. Neither the name of the University nor the names of its contributors 17df930be7Sderaadt * may be used to endorse or promote products derived from this software 18df930be7Sderaadt * without specific prior written permission. 19df930be7Sderaadt * 20df930be7Sderaadt * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21df930be7Sderaadt * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22df930be7Sderaadt * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23df930be7Sderaadt * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24df930be7Sderaadt * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25df930be7Sderaadt * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26df930be7Sderaadt * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27df930be7Sderaadt * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28df930be7Sderaadt * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29df930be7Sderaadt * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30df930be7Sderaadt * SUCH DAMAGE. 31df930be7Sderaadt * 32df930be7Sderaadt * from: @(#)ring.h 8.1 (Berkeley) 6/6/93 33df930be7Sderaadt */ 34df930be7Sderaadt 35df930be7Sderaadt /* 36df930be7Sderaadt * This defines a structure for a ring buffer. 37df930be7Sderaadt * 38df930be7Sderaadt * The circular buffer has two parts: 39df930be7Sderaadt *((( 40df930be7Sderaadt * full: [consume, supply) 41df930be7Sderaadt * empty: [supply, consume) 42df930be7Sderaadt *]]] 43df930be7Sderaadt * 44df930be7Sderaadt */ 45df930be7Sderaadt typedef struct { 463ea84687Sguenther unsigned char *consume; /* where data comes out of */ 473ea84687Sguenther unsigned char *supply; /* where data comes in to */ 483ea84687Sguenther unsigned char *bottom; /* lowest address in buffer */ 493ea84687Sguenther unsigned char *top; /* highest address+1 in buffer */ 503ea84687Sguenther unsigned char *mark; /* marker (user defined) */ 51df930be7Sderaadt int size; /* size in bytes of buffer */ 52*c5bc9e33Sguenther unsigned long consumetime; /* help us keep straight full, empty, etc. */ 53*c5bc9e33Sguenther unsigned long supplytime; 54df930be7Sderaadt } Ring; 55df930be7Sderaadt 56df930be7Sderaadt /* Here are some functions and macros to deal with the ring buffer */ 57df930be7Sderaadt 58df930be7Sderaadt /* Initialization routine */ 593ea84687Sguenther void ring_init(Ring *ring, unsigned char *buffer, int size); 60df930be7Sderaadt 61df930be7Sderaadt /* Data movement routines */ 623ea84687Sguenther void ring_supply_data(Ring *ring, unsigned char *buffer, int count); 63df930be7Sderaadt 64df930be7Sderaadt /* Buffer state transition routines */ 653ea84687Sguenther void ring_supplied(Ring *ring, int count); 663ea84687Sguenther void ring_consumed(Ring *ring, int count); 67df930be7Sderaadt 68df930be7Sderaadt /* Buffer state query routines */ 693ea84687Sguenther int ring_empty_count(Ring *ring); 703ea84687Sguenther int ring_empty_consecutive(Ring *ring); 713ea84687Sguenther int ring_full_count(Ring *ring); 723ea84687Sguenther int ring_full_consecutive(Ring *ring); 73df930be7Sderaadt 743ea84687Sguenther /* Buffer urgent data handling */ 753ea84687Sguenther void ring_clear_mark(Ring *); 763ea84687Sguenther void ring_mark(Ring *); 773ea84687Sguenther int ring_at_mark(Ring *); 783a625bd4Sart 79