priorityq-heap.h

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/*
** License Applicability. Except to the extent portions of this file are
** made subject to an alternative license as permitted in the SGI Free
** Software License B, Version 1.1 (the "License"), the contents of this
** file are subject only to the provisions of the License. You may not use
** this file except in compliance with the License. You may obtain a copy
** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
**
** http://oss.sgi.com/projects/FreeB
**
** Note that, as provided in the License, the Software is distributed on an
** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
**
** Original Code. The Original Code is: OpenGL Sample Implementation,
** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
** Copyright in any portions created by third parties is as indicated
** elsewhere herein. All Rights Reserved.
**
** Additional Notice Provisions: The application programming interfaces
** established by SGI in conjunction with the Original Code are The
** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
** Window System(R) (Version 1.3), released October 19, 1998. This software
** was created using the OpenGL(R) version 1.2.1 Sample Implementation
** published by SGI, but has not been independently verified as being
** compliant with the OpenGL(R) version 1.2.1 Specification.
**
*/
/*
** Author: Eric Veach, July 1994.
**
** $Date: 2007-10-19 23:21:45 +0000 (Fri, 19 Oct 2007) $ $Revision: 1.1 $
** $Header: /cygdrive/c/RCVS/CVS/ReactOS/reactos/lib/glu32/libtess/priorityq-heap.h,v 1.1 2004/02/02 16:39:15 navaraf Exp $
*/

#ifndef __priorityq_heap_h_
#define __priorityq_heap_h_

/* Use #define's so that another heap implementation can use this one */

#define PQkey           PQHeapKey
#define PQhandle        PQHeapHandle
#define PriorityQ       PriorityQHeap

#define pqNewPriorityQ(leq) __gl_pqHeapNewPriorityQ(leq)
#define pqDeletePriorityQ(pq)   __gl_pqHeapDeletePriorityQ(pq)

/* The basic operations are insertion of a new key (pqInsert),
 * and examination/extraction of a key whose value is minimum
 * (pqMinimum/pqExtractMin).  Deletion is also allowed (pqDelete);
 * for this purpose pqInsert returns a "handle" which is supplied
 * as the argument.
 *
 * An initial heap may be created efficiently by calling pqInsert
 * repeatedly, then calling pqInit.  In any case pqInit must be called
 * before any operations other than pqInsert are used.
 *
 * If the heap is empty, pqMinimum/pqExtractMin will return a NULL key.
 * This may also be tested with pqIsEmpty.
 */
#define pqInit(pq)      __gl_pqHeapInit(pq)
#define pqInsert(pq,key)    __gl_pqHeapInsert(pq,key)
#define pqMinimum(pq)       __gl_pqHeapMinimum(pq)
#define pqExtractMin(pq)    __gl_pqHeapExtractMin(pq)
#define pqDelete(pq,handle) __gl_pqHeapDelete(pq,handle)
#define pqIsEmpty(pq)       __gl_pqHeapIsEmpty(pq)


/* Since we support deletion the data structure is a little more
 * complicated than an ordinary heap.  "nodes" is the heap itself;
 * active nodes are stored in the range 1..pq->size.  When the
 * heap exceeds its allocated size (pq->max), its size doubles.
 * The children of node i are nodes 2i and 2i+1.
 *
 * Each node stores an index into an array "handles".  Each handle
 * stores a key, plus a pointer back to the node which currently
 * represents that key (ie. nodes[handles[i].node].handle == i).
 */

typedef void *PQkey;
typedef long PQhandle;
typedef struct PriorityQ PriorityQ;

typedef struct { PQhandle handle; } PQnode;
typedef struct { PQkey key; PQhandle node; } PQhandleElem;

struct PriorityQ {
  PQnode    *nodes;
  PQhandleElem  *handles;
  long      size, max;
  PQhandle  freeList;
  int       initialized;
  int       (*leq)(PQkey key1, PQkey key2);
};

PriorityQ   *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) );
void        pqDeletePriorityQ( PriorityQ *pq );

void        pqInit( PriorityQ *pq );
PQhandle    pqInsert( PriorityQ *pq, PQkey key );
PQkey       pqExtractMin( PriorityQ *pq );
void        pqDelete( PriorityQ *pq, PQhandle handle );


#define __gl_pqHeapMinimum(pq)  ((pq)->handles[(pq)->nodes[1].handle].key)
#define __gl_pqHeapIsEmpty(pq)  ((pq)->size == 0)

#endif