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      1 /*
      2 ** License Applicability. Except to the extent portions of this file are
      3 ** made subject to an alternative license as permitted in the SGI Free
      4 ** Software License B, Version 1.1 (the "License"), the contents of this
      5 ** file are subject only to the provisions of the License. You may not use
      6 ** this file except in compliance with the License. You may obtain a copy
      7 ** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
      8 ** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
      9 **
     10 ** http://oss.sgi.com/projects/FreeB
     11 **
     12 ** Note that, as provided in the License, the Software is distributed on an
     13 ** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
     14 ** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
     15 ** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
     16 ** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
     17 **
     18 ** Original Code. The Original Code is: OpenGL Sample Implementation,
     19 ** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
     20 ** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
     21 ** Copyright in any portions created by third parties is as indicated
     22 ** elsewhere herein. All Rights Reserved.
     23 **
     24 ** Additional Notice Provisions: The application programming interfaces
     25 ** established by SGI in conjunction with the Original Code are The
     26 ** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
     27 ** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
     28 ** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
     29 ** Window System(R) (Version 1.3), released October 19, 1998. This software
     30 ** was created using the OpenGL(R) version 1.2.1 Sample Implementation
     31 ** published by SGI, but has not been independently verified as being
     32 ** compliant with the OpenGL(R) version 1.2.1 Specification.
     33 **
     34 */
     35 /*
     36 ** Author: Eric Veach, July 1994.
     37 **
     38 ** $Date$ $Revision$
     39 ** $Header: //depot/main/gfx/lib/glu/libtess/priorityq-heap.h#5 $
     40 */
     41 
     42 #ifndef __priorityq_heap_h_
     43 #define __priorityq_heap_h_
     44 
     45 /* Use #define's so that another heap implementation can use this one */
     46 
     47 #define PQkey			PQHeapKey
     48 #define PQhandle		PQHeapHandle
     49 #define PriorityQ		PriorityQHeap
     50 
     51 #define pqNewPriorityQ(leq)	__gl_pqHeapNewPriorityQ(leq)
     52 #define pqDeletePriorityQ(pq)	__gl_pqHeapDeletePriorityQ(pq)
     53 
     54 /* The basic operations are insertion of a new key (pqInsert),
     55  * and examination/extraction of a key whose value is minimum
     56  * (pqMinimum/pqExtractMin).  Deletion is also allowed (pqDelete);
     57  * for this purpose pqInsert returns a "handle" which is supplied
     58  * as the argument.
     59  *
     60  * An initial heap may be created efficiently by calling pqInsert
     61  * repeatedly, then calling pqInit.  In any case pqInit must be called
     62  * before any operations other than pqInsert are used.
     63  *
     64  * If the heap is empty, pqMinimum/pqExtractMin will return a NULL key.
     65  * This may also be tested with pqIsEmpty.
     66  */
     67 #define pqInit(pq)		__gl_pqHeapInit(pq)
     68 #define pqInsert(pq,key)	__gl_pqHeapInsert(pq,key)
     69 #define pqMinimum(pq)		__gl_pqHeapMinimum(pq)
     70 #define pqExtractMin(pq)	__gl_pqHeapExtractMin(pq)
     71 #define pqDelete(pq,handle)	__gl_pqHeapDelete(pq,handle)
     72 #define pqIsEmpty(pq)		__gl_pqHeapIsEmpty(pq)
     73 
     74 
     75 /* Since we support deletion the data structure is a little more
     76  * complicated than an ordinary heap.  "nodes" is the heap itself;
     77  * active nodes are stored in the range 1..pq->size.  When the
     78  * heap exceeds its allocated size (pq->max), its size doubles.
     79  * The children of node i are nodes 2i and 2i+1.
     80  *
     81  * Each node stores an index into an array "handles".  Each handle
     82  * stores a key, plus a pointer back to the node which currently
     83  * represents that key (ie. nodes[handles[i].node].handle == i).
     84  */
     85 
     86 typedef void *PQkey;
     87 typedef long PQhandle;
     88 typedef struct PriorityQ PriorityQ;
     89 
     90 typedef struct { PQhandle handle; } PQnode;
     91 typedef struct { PQkey key; PQhandle node; } PQhandleElem;
     92 
     93 struct PriorityQ {
     94   PQnode	*nodes;
     95   PQhandleElem	*handles;
     96   long		size, max;
     97   PQhandle	freeList;
     98   int		initialized;
     99   int		(*leq)(PQkey key1, PQkey key2);
    100 };
    101 
    102 PriorityQ	*pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) );
    103 void		pqDeletePriorityQ( PriorityQ *pq );
    104 
    105 void		pqInit( PriorityQ *pq );
    106 PQhandle	pqInsert( PriorityQ *pq, PQkey key );
    107 PQkey		pqExtractMin( PriorityQ *pq );
    108 void		pqDelete( PriorityQ *pq, PQhandle handle );
    109 
    110 
    111 #define __gl_pqHeapMinimum(pq)	((pq)->handles[(pq)->nodes[1].handle].key)
    112 #define __gl_pqHeapIsEmpty(pq)	((pq)->size == 0)
    113 
    114 #endif
    115