src/glu/sgi/libtess/priorityq-heap.h

   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 */
  39
  40 #ifndef __priorityq_heap_h_
  41 #define __priorityq_heap_h_
  42
  43 /* Use #define's so that another heap implementation can use this one */
  44
  45 #define PQkey                   PQHeapKey
  46 #define PQhandle                PQHeapHandle
  47 #define PriorityQ               PriorityQHeap
  48
  49 #define pqNewPriorityQ(leq)     __gl_pqHeapNewPriorityQ(leq)
  50 #define pqDeletePriorityQ(pq)   __gl_pqHeapDeletePriorityQ(pq)
  51
  52 /* The basic operations are insertion of a new key (pqInsert),
  53  * and examination/extraction of a key whose value is minimum
  54  * (pqMinimum/pqExtractMin).  Deletion is also allowed (pqDelete);
  55  * for this purpose pqInsert returns a "handle" which is supplied
  56  * as the argument.
  57  *
  58  * An initial heap may be created efficiently by calling pqInsert
  59  * repeatedly, then calling pqInit.  In any case pqInit must be called
  60  * before any operations other than pqInsert are used.
  61  *
  62  * If the heap is empty, pqMinimum/pqExtractMin will return a NULL key.
  63  * This may also be tested with pqIsEmpty.
  64  */
  65 #define pqInit(pq)              __gl_pqHeapInit(pq)
  66 #define pqInsert(pq,key)        __gl_pqHeapInsert(pq,key)
  67 #define pqMinimum(pq)           __gl_pqHeapMinimum(pq)
  68 #define pqExtractMin(pq)        __gl_pqHeapExtractMin(pq)
  69 #define pqDelete(pq,handle)     __gl_pqHeapDelete(pq,handle)
  70 #define pqIsEmpty(pq)           __gl_pqHeapIsEmpty(pq)
  71
  72
  73 /* Since we support deletion the data structure is a little more
  74  * complicated than an ordinary heap.  "nodes" is the heap itself;
  75  * active nodes are stored in the range 1..pq->size.  When the
  76  * heap exceeds its allocated size (pq->max), its size doubles.
  77  * The children of node i are nodes 2i and 2i+1.
  78  *
  79  * Each node stores an index into an array "handles".  Each handle
  80  * stores a key, plus a pointer back to the node which currently
  81  * represents that key (ie. nodes[handles[i].node].handle == i).
  82  */
  83
  84 typedef void *PQkey;
  85 typedef long PQhandle;
  86 typedef struct PriorityQ PriorityQ;
  87
  88 typedef struct { PQhandle handle; } PQnode;
  89 typedef struct { PQkey key; PQhandle node; } PQhandleElem;
  90
  91 struct PriorityQ {
  92   PQnode        *nodes;
  93   PQhandleElem  *handles;
  94   long          size, max;
  95   PQhandle      freeList;
  96   int           initialized;
  97   int           (*leq)(PQkey key1, PQkey key2);
  98 };
  99
 100 PriorityQ       *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) );
 101 void            pqDeletePriorityQ( PriorityQ *pq );
 102
 103 void            pqInit( PriorityQ *pq );
 104 PQhandle        pqInsert( PriorityQ *pq, PQkey key );
 105 PQkey           pqExtractMin( PriorityQ *pq );
 106 void            pqDelete( PriorityQ *pq, PQhandle handle );
 107
 108
 109 #define __gl_pqHeapMinimum(pq)  ((pq)->handles[(pq)->nodes[1].handle].key)
 110 #define __gl_pqHeapIsEmpty(pq)  ((pq)->size == 0)
 111
 112 #endif