/* abq.h: QUEUE INTERFACE
 *
 * $Id: //info.ravenbrook.com/project/mps/version/1.113/code/abq.h#1 $
 * Copyright (c) 2001 Ravenbrook Limited.  See end of file for license.
 *
 * .purpose: A fixed-length FIFO queue.
 *
 * .design: <design/abq/>
 */

#ifndef abq_h
#define abq_h

#include "meter.h"
#include "mpm.h"


/* Signatures */

#define ABQSig ((Sig)0x519AB099) /* SIGnature ABQ */


/* Prototypes  */

typedef struct ABQStruct *ABQ;
typedef Res (*ABQDescribeElement)(void *element, mps_lib_FILE *stream);
typedef Bool (*ABQIterateMethod)(Bool *deleteReturn, void *element, void *closureP, Size closureS);

extern Res ABQInit(Arena arena, ABQ abq, void *owner, Count elements, Size elementSize);
extern Bool ABQCheck(ABQ abq);
extern void ABQFinish(Arena arena, ABQ abq);
extern Bool ABQPush(ABQ abq, void *element);
extern Bool ABQPop(ABQ abq, void *elementReturn);
extern Bool ABQPeek(ABQ abq, void *elementReturn);
extern Res ABQDescribe(ABQ abq, ABQDescribeElement describeElement, mps_lib_FILE *stream);
extern Bool ABQIsEmpty(ABQ abq);
extern Bool ABQIsFull(ABQ abq);
extern Count ABQDepth(ABQ abq);
extern void ABQIterate(ABQ abq, ABQIterateMethod iterate, void *closureP, Size closureS);


/* Types */

typedef struct ABQStruct
{
  Count elements;
  Size elementSize;
  Index in;
  Index out;
  void *queue;

  /* Meter queue depth at each operation */
  METER_DECL(push);
  METER_DECL(pop);
  METER_DECL(peek);
  METER_DECL(delete);
 
  Sig sig;
} ABQStruct;

#endif /* abq_h */


/* C. COPYRIGHT AND LICENSE
 *
 * Copyright (C) 2001-2002 Ravenbrook Limited <http://www.ravenbrook.com/>.
 * All rights reserved.  This is an open source license.  Contact
 * Ravenbrook for commercial licensing options.
 * 
 * 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.
 * 
 * 3. Redistributions in any form must be accompanied by information on how
 * to obtain complete source code for this software and any accompanying
 * software that uses this software.  The source code must either be
 * included in the distribution or be available for no more than the cost
 * of distribution plus a nominal fee, and must be freely redistributable
 * under reasonable conditions.  For an executable file, complete source
 * code means the source code for all modules it contains. It does not
 * include source code for modules or files that typically accompany the
 * major components of the operating system on which the executable file
 * runs.
 * 
 * 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, FITNESS FOR A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT, ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS AND 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.
 */
