/* ring.h: RING INTERFACE
*
* $Id: //info.ravenbrook.com/project/mps/master/code/ring.h#20 $
* Copyright (c) 2001-2020 Ravenbrook Limited. See end of file for license.
* Portions copyright (C) 2001 Global Graphics Software.
*/
#ifndef ring_h
#define ring_h
#include "check.h"
#include "mpmtypes.h"
/* RingStruct -- double-ended queue structure
*
* .ring: The ring structure is used as a field in other structures
* in order to link them together into "rings". See <code/ring.c>.
*/
typedef struct RingStruct *Ring;
typedef struct RingStruct { /* double-ended queue structure */
Ring next, prev; /* links to next and prev element */
} RingStruct;
#define RingNONE ((Ring)0)
extern Bool RingCheck(Ring ring);
extern Bool RingCheckSingle(Ring ring);
extern Bool RingIsSingle(Ring ring);
extern Count RingLength(Ring ring);
/* .ring.init: <design/ring#.init> */
extern void (RingInit)(Ring ring);
#define RingInit(ring) \
BEGIN \
Ring _ring = (ring); \
AVER(_ring != NULL); \
_ring->next = _ring; \
_ring->prev = _ring; \
AVER(RingCheck(_ring)); \
END
/* .ring.finish: <design/ring#.finish> */
extern void (RingFinish)(Ring ring);
#define RingFinish(ring) \
BEGIN \
Ring _ring = (ring); \
AVER(RingCheckSingle(_ring)); \
_ring->next = RingNONE; \
_ring->prev = RingNONE; \
END
/* .ring.append: <design/ring#.append> */
extern void (RingAppend)(Ring ring, Ring new);
#define RingAppend(ring, new) \
BEGIN \
Ring _ring = (ring), _new = (new); \
AVER(RingCheck(_ring)); \
AVER(RingCheckSingle(_new)); \
_new->prev = _ring->prev; \
_new->next = _ring; \
_ring->prev->next = _new; \
_ring->prev = _new; \
END
/* .ring.insert: */
extern void (RingInsert)(Ring ring, Ring new);
#define RingInsert(ring, new) \
BEGIN \
Ring _ring = (ring), _new = (new); \
AVER(RingCheck(_ring)); \
AVER(RingCheckSingle(_new)); \
_new->prev = _ring; \
_new->next = _ring->next; \
_ring->next->prev = _new; \
_ring->next = _new; \
END
/* .ring.remove: <design/ring#.remove> */
extern void (RingRemove)(Ring old);
#define RingRemove(old) \
BEGIN \
Ring _old = (old); \
AVER(RingCheck(_old)); \
AVER(!RingIsSingle(_old)); \
_old->next->prev = _old->prev; \
_old->prev->next = _old->next; \
_old->next = _old; \
_old->prev = _old; \
END
/* .ring.next: <design/ring#.next> */
extern Ring (RingNext)(Ring ring);
#define RingNext(ring) ((ring)->next)
/* .ring.prev: <design/ring#.prev> */
extern Ring (RingPrev)(Ring ring);
#define RingPrev(ring) ((ring)->prev)
/* .ring.elt: <design/ring#.elt> */
#define RING_ELT(type, field, node) \
PARENT(type ## Struct, field, node)
/* .ring.for: <design/ring#.for> */
#define RING_FOR(node, ring, next) \
for (ITER_PARALLEL(node = RingNext(ring), next = RingNext(node)); \
node != (ring); \
ITER_PARALLEL(node = (next), next = RingNext(node)))
#endif /* ring_h */
/* C. COPYRIGHT AND LICENSE
*
* Copyright (C) 2001-2020 Ravenbrook Limited <https://www.ravenbrook.com/>.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/