1 /* 2 ** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008) 3 ** Copyright (C) [dates of first publication] Silicon Graphics, Inc. 4 ** All Rights Reserved. 5 ** 6 ** Permission is hereby granted, free of charge, to any person obtaining a copy 7 ** of this software and associated documentation files (the "Software"), to deal 8 ** in the Software without restriction, including without limitation the rights 9 ** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 10 ** of the Software, and to permit persons to whom the Software is furnished to do so, 11 ** subject to the following conditions: 12 ** 13 ** The above copyright notice including the dates of first publication and either this 14 ** permission notice or a reference to http://oss.sgi.com/projects/FreeB/ shall be 15 ** included in all copies or substantial portions of the Software. 16 ** 17 ** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 18 ** INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 19 ** PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL SILICON GRAPHICS, INC. 20 ** BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 21 ** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE 22 ** OR OTHER DEALINGS IN THE SOFTWARE. 23 ** 24 ** Except as contained in this notice, the name of Silicon Graphics, Inc. shall not 25 ** be used in advertising or otherwise to promote the sale, use or other dealings in 26 ** this Software without prior written authorization from Silicon Graphics, Inc. 27 */ 28 /* 29 ** Author: Eric Veach, July 1994. 30 */ 31 32 #ifndef PRIORITYQ_H 33 #define PRIORITYQ_H 34 35 /* The basic operations are insertion of a new key (pqInsert), 36 * and examination/extraction of a key whose value is minimum 37 * (pqMinimum/pqExtractMin). Deletion is also allowed (pqDelete); 38 * for this purpose pqInsert returns a "handle" which is supplied 39 * as the argument. 40 * 41 * An initial heap may be created efficiently by calling pqInsert 42 * repeatedly, then calling pqInit. In any case pqInit must be called 43 * before any operations other than pqInsert are used. 44 * 45 * If the heap is empty, pqMinimum/pqExtractMin will return a NULL key. 46 * This may also be tested with pqIsEmpty. 47 */ 48 49 /* Since we support deletion the data structure is a little more 50 * complicated than an ordinary heap. "nodes" is the heap itself; 51 * active nodes are stored in the range 1..pq->size. When the 52 * heap exceeds its allocated size (pq->max), its size doubles. 53 * The children of node i are nodes 2i and 2i+1. 54 * 55 * Each node stores an index into an array "handles". Each handle 56 * stores a key, plus a pointer back to the node which currently 57 * represents that key (ie. nodes[handles[i].node].handle == i). 58 */ 59 60 typedef void *PQkey; 61 typedef int PQhandle; 62 typedef struct PriorityQHeap PriorityQHeap; 63 64 #define INV_HANDLE 0x0fffffff 65 66 typedef struct { PQhandle handle; } PQnode; 67 typedef struct { PQkey key; PQhandle node; } PQhandleElem; 68 69 struct PriorityQHeap { 70 71 PQnode *nodes; 72 PQhandleElem *handles; 73 int size, max; 74 PQhandle freeList; 75 int initialized; 76 77 int (*leq)(PQkey key1, PQkey key2); 78 }; 79 80 typedef struct PriorityQ PriorityQ; 81 82 struct PriorityQ { 83 PriorityQHeap *heap; 84 85 PQkey *keys; 86 PQkey **order; 87 PQhandle size, max; 88 int initialized; 89 90 int (*leq)(PQkey key1, PQkey key2); 91 }; 92 93 PriorityQ *pqNewPriorityQ( TESSalloc* alloc, int size, int (*leq)(PQkey key1, PQkey key2) ); 94 void pqDeletePriorityQ( TESSalloc* alloc, PriorityQ *pq ); 95 96 int pqInit( TESSalloc* alloc, PriorityQ *pq ); 97 PQhandle pqInsert( TESSalloc* alloc, PriorityQ *pq, PQkey key ); 98 PQkey pqExtractMin( PriorityQ *pq ); 99 void pqDelete( PriorityQ *pq, PQhandle handle ); 100 101 PQkey pqMinimum( PriorityQ *pq ); 102 int pqIsEmpty( PriorityQ *pq ); 103 104 #endif 105