usr.bin/telnet/ring.h

   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  * 3. 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  * $FreeBSD: src/crypto/telnet/telnet/ring.h,v 1.1.1.1.8.1 2002/04/13 10:59:08 markm Exp $
  31  */
  32
  33 /*
  34  * This defines a structure for a ring buffer.
  35  *
  36  * The circular buffer has two parts:
  37  *(((
  38  *      full:   [consume, supply)
  39  *      empty:  [supply, consume)
  40  *]]]
  41  *
  42  */
  43 typedef struct {
  44     unsigned char       *consume,       /* where data comes out of */
  45                         *supply,        /* where data comes in to */
  46                         *bottom,        /* lowest address in buffer */
  47                         *top,           /* highest address+1 in buffer */
  48                         *mark;          /* marker (user defined) */
  49 #ifdef  ENCRYPTION
  50     unsigned char       *clearto;       /* Data to this point is clear text */
  51     unsigned char       *encryyptedto;  /* Data is encrypted to here */
  52 #endif  /* ENCRYPTION */
  53     int         size;           /* size in bytes of buffer */
  54     u_long      consumetime,    /* help us keep straight full, empty, etc. */
  55                 supplytime;
  56 } Ring;
  57
  58 /* Here are some functions and macros to deal with the ring buffer */
  59
  60 /* Initialization routine */
  61 extern int
  62         ring_init(Ring *ring, unsigned char *buffer, int count);
  63
  64 /* Data movement routines */
  65 extern void
  66         ring_supply_data(Ring *ring, unsigned char *buffer, int count);
  67 #ifdef notdef
  68 extern void
  69         ring_consume_data(Ring *ring, unsigned char *buffer, int count);
  70 #endif
  71
  72 /* Buffer state transition routines */
  73 extern void
  74         ring_supplied(Ring *ring, int count),
  75         ring_consumed(Ring *ring, int count);
  76
  77 /* Buffer state query routines */
  78 extern int
  79         ring_at_mark(Ring *),
  80         ring_empty_count(Ring *ring),
  81         ring_empty_consecutive(Ring *ring),
  82         ring_full_count(Ring *ring),
  83         ring_full_consecutive(Ring *ring);
  84
  85 #ifdef  ENCRYPTION
  86 extern void
  87         ring_encrypt(Ring *ring, void (*func)(unsigned char *, int)),
  88         ring_clearto(Ring *ring);
  89 #endif  /* ENCRYPTION */
  90
  91 extern void
  92         ring_clear_mark(Ring *),
  93         ring_mark(Ring *);