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
86typedef void *PQkey;
87typedef long PQhandle;
88typedef struct PriorityQ PriorityQ;
89
90typedef struct { PQhandle handle; } PQnode;
91typedef struct { PQkey key; PQhandle node; } PQhandleElem;
92
93struct 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
102PriorityQ	*pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) );
103void		pqDeletePriorityQ( PriorityQ *pq );
104
105void		pqInit( PriorityQ *pq );
106PQhandle	pqInsert( PriorityQ *pq, PQkey key );
107PQkey		pqExtractMin( PriorityQ *pq );
108void		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