freebsd-skq/sys/netatm/queue.h

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/*-
*
* ===================================
* HARP | Host ATM Research Platform
* ===================================
*
*
* This Host ATM Research Platform ("HARP") file (the "Software") is
* made available by Network Computing Services, Inc. ("NetworkCS")
* "AS IS". NetworkCS does not provide maintenance, improvements or
* support of any kind.
*
* NETWORKCS MAKES NO WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED,
* INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE, AS TO ANY ELEMENT OF THE
* SOFTWARE OR ANY SUPPORT PROVIDED IN CONNECTION WITH THIS SOFTWARE.
* In no event shall NetworkCS be responsible for any damages, including
* but not limited to consequential damages, arising from or relating to
* any use of the Software or related support.
*
* Copyright 1994-1998 Network Computing Services, Inc.
*
* Copies of this Software may be made, however, the above copyright
* notice must be reproduced on all copies.
*
1999-08-28 01:08:13 +00:00
* @(#) $FreeBSD$
*
*/
/*
* Core ATM Services
* -----------------
*
* General queueing/linking definitions
*
*/
#ifndef _NETATM_QUEUE_H
#define _NETATM_QUEUE_H
/*
* Structure defining the queue controls for a doubly linked queue
*/
struct q_queue {
caddr_t q_head; /* Head of queue */
caddr_t q_tail; /* Tail of queue */
};
typedef struct q_queue Queue_t;
/*
* Structure defining the queue elements of a doubly linked queue
*/
struct q_elem {
caddr_t q_forw; /* Forward link */
caddr_t q_back; /* Backward link */
};
typedef struct q_elem Qelem_t;
/*
* Macro to add a control block onto the tail of a doubly linked queue
* e = control block to add
* t = control block structure type
* el = name of control block's q_elem field
* q = pointer to queue controls
*/
#define ENQUEUE(e,t,el,q) \
{ \
(e)->el.q_forw = NULL; \
(e)->el.q_back = (q).q_tail; \
if ((q).q_head == NULL) { \
(q).q_head = (caddr_t)(e); \
(q).q_tail = (caddr_t)(e); \
} else { \
((t *)(q).q_tail)->el.q_forw = (caddr_t)(e); \
(q).q_tail = (caddr_t)(e); \
} \
}
/*
* Macro to remove a control block from a doubly linked queue
* e = control block to remove
* t = control block structure type
* el = name of control block's q_elem field
* q = pointer to queue controls
*/
#define DEQUEUE(e,t,el,q) \
{ \
/* Ensure control block is on queue */ \
if ((e)->el.q_forw || (q).q_tail == (caddr_t)(e)) { \
if ((e)->el.q_forw) \
((t *)(e)->el.q_forw)->el.q_back = (e)->el.q_back;\
else \
(q).q_tail = (e)->el.q_back; \
if ((e)->el.q_back) \
((t *)(e)->el.q_back)->el.q_forw = (e)->el.q_forw;\
else \
(q).q_head = (e)->el.q_forw; \
} \
(e)->el.q_back = (e)->el.q_forw = NULL; \
}
/*
* Macro to return the head of a doubly linked queue
* q = pointer to queue controls
* t = control block structure type
*/
#define Q_HEAD(q,t) ((t *)(q).q_head)
/*
* Macro to return the next control block of a doubly linked queue
* e = current control block
* t = control block structure type
* el = name of control block's q_elem field
*/
#define Q_NEXT(e,t,el) ((t *)(e)->el.q_forw)
/*
* Macro to add a control block onto the head of a singly linked chain
* u = control block to add
* t = structure type
* h = head of chain
* l = name of link field
*/
#define LINK2HEAD(u,t,h,l) \
{ \
(u)->l = (h); \
(h) = (u); \
}
/*
* Macro to add a control block onto the tail of a singly linked chain
* u = control block to add
* t = structure type
* h = head of chain
* l = name of link field
*/
#define LINK2TAIL(u,t,h,l) \
{ \
(u)->l = (t *)NULL; \
/* Check for empty chain */ \
if ((h) == (t *)NULL) { \
(h) = (u); \
} else { \
t *tp; \
/* Loop until we find the end of chain */ \
for (tp = (h); tp->l != (t *)NULL; tp = tp->l) \
; \
tp->l = (u); \
} \
}
/*
* Macro to remove a control block from a singly linked chain
* u = control block to unlink
* t = structure type
* h = head of chain
* l = name of link field
*/
#define UNLINK(u,t,h,l) \
{ \
/* Check for control block at head of chain */ \
if ((u) == (h)) { \
(h) = (u)->l; \
} else { \
t *tp; \
/* Loop until we find the control block */ \
for (tp = (h); tp != (t *)NULL; tp = tp->l) { \
if (tp->l == (u)) \
break; \
} \
if (tp) { \
/* Remove it from chain */ \
tp->l = (u)->l; \
} \
} \
(u)->l = (t *)NULL; \
}
/*
* Macro to remove a control block from a singly linked chain and return
* an indication of whether the block was found
* u = control block to unlink
* t = structure type
* h = head of chain
* l = name of link field
* f = flag; 1 => control block found on chain; else 0
*/
#define UNLINKF(u,t,h,l,f) \
{ \
/* Check for control block at head of chain */ \
if ((u) == (h)) { \
(h) = (u)->l; \
(f) = 1; \
} else { \
t *tp; \
/* Loop until we find the control block */ \
for (tp = (h); tp != (t *)NULL; tp = tp->l) { \
if (tp->l == (u)) \
break; \
} \
if (tp) { \
/* Remove it from chain */ \
tp->l = (u)->l; \
(f) = 1; \
} else \
/* It wasn't on the chain */ \
(f) = 0; \
} \
(u)->l = (t *)NULL; \
}
#endif /* _NETATM_QUEUE_H */