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99 lines
3.2 KiB
C
99 lines
3.2 KiB
C
/*
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* Copyright (c) 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ring.h 8.1 (Berkeley) 6/6/93
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* $FreeBSD$
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*/
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#if defined(P)
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# undef P
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#endif
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#if defined(__STDC__) || defined(LINT_ARGS)
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# define P(x) x
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#else
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# define P(x) ()
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#endif
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/*
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* This defines a structure for a ring buffer.
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*
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* The circular buffer has two parts:
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*(((
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* full: [consume, supply)
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* empty: [supply, consume)
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*]]]
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*
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*/
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typedef struct {
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unsigned char *consume, /* where data comes out of */
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*supply, /* where data comes in to */
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*bottom, /* lowest address in buffer */
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*top, /* highest address+1 in buffer */
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*mark; /* marker (user defined) */
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int size; /* size in bytes of buffer */
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u_long consumetime, /* help us keep straight full, empty, etc. */
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supplytime;
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} Ring;
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/* Here are some functions and macros to deal with the ring buffer */
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/* Initialization routine */
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extern int
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ring_init(Ring *ring, unsigned char *buffer, int count);
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/* Data movement routines */
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extern void
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ring_supply_data(Ring *ring, unsigned char *buffer, int count);
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#ifdef notdef
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extern void
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ring_consume_data(Ring *ring, unsigned char *buffer, int count);
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#endif
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/* Buffer state transition routines */
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extern void
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ring_supplied(Ring *ring, int count),
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ring_consumed(Ring *ring, int count);
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/* Buffer state query routines */
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extern int
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ring_at_mark(Ring *),
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ring_empty_count(Ring *ring),
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ring_empty_consecutive(Ring *ring),
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ring_full_count(Ring *ring),
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ring_full_consecutive(Ring *ring);
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extern void
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ring_clear_mark(Ring *),
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ring_mark(Ring *);
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