FreeWRL/FreeX3D  3.0.0
priorityq.h
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30 /*
31 ** Author: Eric Veach, July 1994.
32 **
33 */
34 
35 #ifndef __priorityq_sort_h_
36 #define __priorityq_sort_h_
37 
38 #include "priorityq-heap.h"
39 
40 #undef PQkey
41 #undef PQhandle
42 #undef PriorityQ
43 #undef pqNewPriorityQ
44 #undef pqDeletePriorityQ
45 #undef pqInit
46 #undef pqInsert
47 #undef pqMinimum
48 #undef pqExtractMin
49 #undef pqDelete
50 #undef pqIsEmpty
51 
52 /* Use #define's so that another heap implementation can use this one */
53 
54 #define PQkey PQSortKey
55 #define PQhandle PQSortHandle
56 #define PriorityQ PriorityQSort
57 
58 #define pqNewPriorityQ(leq) __gl_pqSortNewPriorityQ(leq)
59 #define pqDeletePriorityQ(pq) __gl_pqSortDeletePriorityQ(pq)
60 
61 /* The basic operations are insertion of a new key (pqInsert),
62  * and examination/extraction of a key whose value is minimum
63  * (pqMinimum/pqExtractMin). Deletion is also allowed (pqDelete);
64  * for this purpose pqInsert returns a "handle" which is supplied
65  * as the argument.
66  *
67  * An initial heap may be created efficiently by calling pqInsert
68  * repeatedly, then calling pqInit. In any case pqInit must be called
69  * before any operations other than pqInsert are used.
70  *
71  * If the heap is empty, pqMinimum/pqExtractMin will return a NULL key.
72  * This may also be tested with pqIsEmpty.
73  */
74 #define pqInit(pq) __gl_pqSortInit(pq)
75 #define pqInsert(pq,key) __gl_pqSortInsert(pq,key)
76 #define pqMinimum(pq) __gl_pqSortMinimum(pq)
77 #define pqExtractMin(pq) __gl_pqSortExtractMin(pq)
78 #define pqDelete(pq,handle) __gl_pqSortDelete(pq,handle)
79 #define pqIsEmpty(pq) __gl_pqSortIsEmpty(pq)
80 
81 
82 /* Since we support deletion the data structure is a little more
83  * complicated than an ordinary heap. "nodes" is the heap itself;
84  * active nodes are stored in the range 1..pq->size. When the
85  * heap exceeds its allocated size (pq->max), its size doubles.
86  * The children of node i are nodes 2i and 2i+1.
87  *
88  * Each node stores an index into an array "handles". Each handle
89  * stores a key, plus a pointer back to the node which currently
90  * represents that key (ie. nodes[handles[i].node].handle == i).
91  */
92 
93 typedef PQHeapKey PQkey;
94 typedef PQHeapHandle PQhandle;
95 typedef struct PriorityQ PriorityQ;
96 
97 struct PriorityQ {
98  PriorityQHeap *heap;
99  PQkey *keys;
100  PQkey **order;
101  PQhandle size, max;
102  int initialized;
103  int (*leq)(PQkey key1, PQkey key2);
104 };
105 
106 PriorityQ *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) );
107 void pqDeletePriorityQ( PriorityQ *pq );
108 
109 int pqInit( PriorityQ *pq );
110 PQhandle pqInsert( PriorityQ *pq, PQkey key );
111 PQkey pqExtractMin( PriorityQ *pq );
112 void pqDelete( PriorityQ *pq, PQhandle handle );
113 
114 PQkey pqMinimum( PriorityQ *pq );
115 int pqIsEmpty( PriorityQ *pq );
116 
117 #endif
key
Definition: Viewer.h:174