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  1. /*
  2.  * Copyright (c) 1988, 1993
  3.  *      The Regents of the University of California.  All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  * 1. Redistributions of source code must retain the above copyright
  9.  *    notice, this list of conditions and the following disclaimer.
  10.  * 2. Redistributions in binary form must reproduce the above copyright
  11.  *    notice, this list of conditions and the following disclaimer in the
  12.  *    documentation and/or other materials provided with the distribution.
  13.  * 4. Neither the name of the University nor the names of its contributors
  14.  *    may be used to endorse or promote products derived from this software
  15.  *    without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18.  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19.  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20.  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21.  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22.  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23.  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24.  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25.  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26.  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27.  * SUCH DAMAGE.
  28.  *
  29.  *      @(#)ring.h      8.1 (Berkeley) 6/6/93
  30.  */
  31.  
  32. #if defined(P)
  33. # undef P
  34. #endif
  35.  
  36. #if defined(__STDC__) || defined(LINT_ARGS)
  37. # define        P(x)    x
  38. #else
  39. # define        P(x)    ()
  40. #endif
  41.  
  42. /*
  43.  * This defines a structure for a ring buffer.
  44.  *
  45.  * The circular buffer has two parts:
  46.  *(((
  47.  *      full:   [consume, supply)
  48.  *      empty:  [supply, consume)
  49.  *]]]
  50.  *
  51.  */
  52. typedef struct {
  53.     unsigned char       *consume,       /* where data comes out of */
  54.                         *supply,        /* where data comes in to */
  55.                         *bottom,        /* lowest address in buffer */
  56.                         *top,           /* highest address+1 in buffer */
  57.                         *mark;          /* marker (user defined) */
  58. #ifdef  ENCRYPTION
  59.     unsigned char       *clearto;       /* Data to this point is clear text */
  60.     unsigned char       *encryyptedto;  /* Data is encrypted to here */
  61. #endif  /* ENCRYPTION */
  62.     int         size;           /* size in bytes of buffer */
  63.     u_long      consumetime,    /* help us keep straight full, empty, etc. */
  64.                 supplytime;
  65. } Ring;
  66.  
  67. /* Here are some functions and macros to deal with the ring buffer */
  68.  
  69. /* Initialization routine */
  70. extern int
  71.         ring_init P((Ring *ring, unsigned char *buffer, int count));
  72.  
  73. /* Data movement routines */
  74. extern void
  75.         ring_supply_data P((Ring *ring, unsigned char *buffer, int count));
  76. #ifdef notdef
  77. extern void
  78.         ring_consume_data P((Ring *ring, unsigned char *buffer, int count));
  79. #endif
  80.  
  81. /* Buffer state transition routines */
  82. extern void
  83.         ring_supplied P((Ring *ring, int count)),
  84.         ring_consumed P((Ring *ring, int count));
  85.  
  86. /* Buffer state query routines */
  87. extern int
  88.         ring_empty_count P((Ring *ring)),
  89.         ring_empty_consecutive P((Ring *ring)),
  90.         ring_full_count P((Ring *ring)),
  91.         ring_full_consecutive P((Ring *ring));
  92.  
  93. #ifdef  ENCRYPTION
  94. extern void
  95.         ring_encrypt P((Ring *ring, void (*func)())),
  96.         ring_clearto P((Ring *ring));
  97. #endif  /* ENCRYPTION */
  98.  
  99. extern void ring_clear_mark P ((Ring *));
  100. extern void ring_mark P ((Ring *));
  101.