Home | History | Annotate | Line # | Download | only in telnet
ring.h revision 1.1 
      1 /*
      2  * Copyright (c) 1988 Regents of the University of California.
      3  * 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. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  *
     33  *	@(#)ring.h	5.2 (Berkeley) 3/1/91
     34  */
     35 
     36 #if defined(P)
     37 # undef P
     38 #endif
     39 
     40 #if defined(__STDC__) || defined(LINT_ARGS)
     41 # define	P(x)	x
     42 #else
     43 # define	P(x)	()
     44 #endif
     45 
     46 /*
     47  * This defines a structure for a ring buffer.
     48  *
     49  * The circular buffer has two parts:
     50  *(((
     51  *	full:	[consume, supply)
     52  *	empty:	[supply, consume)
     53  *]]]
     54  *
     55  */
     56 typedef struct {
     57     unsigned char	*consume,	/* where data comes out of */
     58 			*supply,	/* where data comes in to */
     59 			*bottom,	/* lowest address in buffer */
     60 			*top,		/* highest address+1 in buffer */
     61 			*mark;		/* marker (user defined) */
     62 #if	defined(ENCRYPT)
     63     unsigned char	*clearto;	/* Data to this point is clear text */
     64     unsigned char	*encryyptedto;	/* Data is encrypted to here */
     65 #endif
     66     int		size;		/* size in bytes of buffer */
     67     u_long	consumetime,	/* help us keep straight full, empty, etc. */
     68 		supplytime;
     69 } Ring;
     70 
     71 /* Here are some functions and macros to deal with the ring buffer */
     72 
     73 /* Initialization routine */
     74 extern int
     75 	ring_init P((Ring *ring, unsigned char *buffer, int count));
     76 
     77 /* Data movement routines */
     78 extern void
     79 	ring_supply_data P((Ring *ring, unsigned char *buffer, int count));
     80 #ifdef notdef
     81 extern void
     82 	ring_consume_data P((Ring *ring, unsigned char *buffer, int count));
     83 #endif
     84 
     85 /* Buffer state transition routines */
     86 extern void
     87 	ring_supplied P((Ring *ring, int count)),
     88 	ring_consumed P((Ring *ring, int count));
     89 
     90 /* Buffer state query routines */
     91 extern int
     92 	ring_empty_count P((Ring *ring)),
     93 	ring_empty_consecutive P((Ring *ring)),
     94 	ring_full_count P((Ring *ring)),
     95 	ring_full_consecutive P((Ring *ring));
     96 
     97 #if	defined(ENCRYPT)
     98 extern void
     99 	ring_encrypt P((Ring *ring, void (*func)())),
    100 	ring_clearto P((Ring *ring));
    101 #endif
    102 
    103 extern void
    104     ring_clear_mark(),
    105     ring_mark();
    106