text: /*
   * 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.
   *
   */
  
  #include <sys/cdefs.h>
  #define P __P
  
  /*
   * 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) */
  #if    defined(ENCRYPTION)
      unsigned char	*clearto;       /* Data to this point is clear text */
      unsigned char	*encryyptedto;  /* Data is encrypted to here */
  #endif
      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));
  
  #if    defined(ENCRYPTION)
  extern void
  	ring_encrypt (Ring *ring, void (*func)()),
  	ring_clearto (Ring *ring);
  #endif
  
  
  extern void
      ring_clear_mark P((Ring *)),
      ring_mark P((Ring *));
  
  
  extern int
      ring_at_mark P((Ring *));
  