1 /* 2 * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008) 3 * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved. 4 * 5 * Permission is hereby granted, free of charge, to any person obtaining a 6 * copy of this software and associated documentation files (the "Software"), 7 * to deal in the Software without restriction, including without limitation 8 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 9 * and/or sell copies of the Software, and to permit persons to whom the 10 * Software is furnished to do so, subject to the following conditions: 11 * 12 * The above copyright notice including the dates of first publication and 13 * either this permission notice or a reference to 14 * http://oss.sgi.com/projects/FreeB/ 15 * shall be included in all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 21 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF 22 * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 23 * SOFTWARE. 24 * 25 * Except as contained in this notice, the name of Silicon Graphics, Inc. 26 * shall not be used in advertising or otherwise to promote the sale, use or 27 * other dealings in this Software without prior written authorization from 28 * Silicon Graphics, Inc. 29 */ 30 /* 31 ** Author: Eric Veach, July 1994. 32 ** 33 */ 34 35 #ifndef __priorityq_heap_h_ 36 #define __priorityq_heap_h_ 37 38 /* Use #define's so that another heap implementation can use this one */ 39 40 #define PQkey PQHeapKey 41 #define PQhandle PQHeapHandle 42 #define PriorityQ PriorityQHeap 43 44 #define pqNewPriorityQ(leq) __gl_pqHeapNewPriorityQ(leq) 45 #define pqDeletePriorityQ(pq) __gl_pqHeapDeletePriorityQ(pq) 46 47 /* The basic operations are insertion of a new key (pqInsert), 48 * and examination/extraction of a key whose value is minimum 49 * (pqMinimum/pqExtractMin). Deletion is also allowed (pqDelete); 50 * for this purpose pqInsert returns a "handle" which is supplied 51 * as the argument. 52 * 53 * An initial heap may be created efficiently by calling pqInsert 54 * repeatedly, then calling pqInit. In any case pqInit must be called 55 * before any operations other than pqInsert are used. 56 * 57 * If the heap is empty, pqMinimum/pqExtractMin will return a NULL key. 58 * This may also be tested with pqIsEmpty. 59 */ 60 #define pqInit(pq) __gl_pqHeapInit(pq) 61 #define pqInsert(pq,key) __gl_pqHeapInsert(pq,key) 62 #define pqMinimum(pq) __gl_pqHeapMinimum(pq) 63 #define pqExtractMin(pq) __gl_pqHeapExtractMin(pq) 64 #define pqDelete(pq,handle) __gl_pqHeapDelete(pq,handle) 65 #define pqIsEmpty(pq) __gl_pqHeapIsEmpty(pq) 66 67 68 /* Since we support deletion the data structure is a little more 69 * complicated than an ordinary heap. "nodes" is the heap itself; 70 * active nodes are stored in the range 1..pq->size. When the 71 * heap exceeds its allocated size (pq->max), its size doubles. 72 * The children of node i are nodes 2i and 2i+1. 73 * 74 * Each node stores an index into an array "handles". Each handle 75 * stores a key, plus a pointer back to the node which currently 76 * represents that key (ie. nodes[handles[i].node].handle == i). 77 */ 78 79 typedef void *PQkey; 80 typedef long PQhandle; 81 typedef struct PriorityQ PriorityQ; 82 83 typedef struct { PQhandle handle; } PQnode; 84 typedef struct { PQkey key; PQhandle node; } PQhandleElem; 85 86 struct PriorityQ { 87 PQnode *nodes; 88 PQhandleElem *handles; 89 long size, max; 90 PQhandle freeList; 91 int initialized; 92 int (*leq)(PQkey key1, PQkey key2); 93 }; 94 95 PriorityQ *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) ); 96 void pqDeletePriorityQ( PriorityQ *pq ); 97 98 void pqInit( PriorityQ *pq ); 99 PQhandle pqInsert( PriorityQ *pq, PQkey key ); 100 PQkey pqExtractMin( PriorityQ *pq ); 101 void pqDelete( PriorityQ *pq, PQhandle handle ); 102 103 104 #define __gl_pqHeapMinimum(pq) ((pq)->handles[(pq)->nodes[1].handle].key) 105 #define __gl_pqHeapIsEmpty(pq) ((pq)->size == 0) 106 107 #endif 108