BSD 4_3_Net_1 release

[unix-history] / tn3270 / telnet / Source / ring.h

/*
* Copyright (c) 1988 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley.  The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
*      @(#)ring.h      1.8 (Berkeley) 6/29/88
*/

/*
* This defines a structure for a ring buffer.
*
* The circular buffer has two parts:
*(((
*      full:   [consume, supply)
*      empty:  [supply, consume)
*]]]
*
*/
typedef struct {
   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) */
   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 */


#if     defined(LINT_ARGS)

/* Initialization routine */
extern int
       ring_init(Ring *ring, char *buffer, int count);

/* Data movement routines */
extern void
       ring_supply_data(Ring *ring, char *buffer, int count),
       ring_consume_data(Ring *ring, char *buffer, int count);

/* Buffer state transition routines */
extern void
       ring_supplied(Ring *ring, int count),
       ring_consumed(Ring *ring, int count);

/* Buffer state query routines */
extern int
       ring_empty_count(Ring *ring),
       ring_empty_consecutive(Ring *ring),
       ring_full_count(Ring *ring),
       ring_full_consecutive(Ring *ring);

#else /* LINT_ARGS */
extern int
       ring_init();

extern void
   ring_supply_data(),
   ring_consume_data();

extern void
   ring_supplied(),
   ring_consumed();

extern void
   ring_clear_mark(),
   ring_mark();

extern int
   ring_empty_count(),
   ring_empty_consecutive(),
   ring_full_count(),
   ring_full_consecutive();
#endif  /* defined(LINT_ARGS) */