93 lines
3.2 KiB
C
93 lines
3.2 KiB
C
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#ifndef __priorityq_heap_h_
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#define __priorityq_heap_h_
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/*
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** Copyright 1994, Silicon Graphics, Inc.
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** All Rights Reserved.
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**
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** This is UNPUBLISHED PROPRIETARY SOURCE CODE of Silicon Graphics, Inc.;
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** the contents of this file may not be disclosed to third parties, copied or
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** duplicated in any form, in whole or in part, without the prior written
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** permission of Silicon Graphics, Inc.
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**
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** RESTRICTED RIGHTS LEGEND:
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** Use, duplication or disclosure by the Government is subject to restrictions
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** as set forth in subdivision (c)(1)(ii) of the Rights in Technical Data
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** and Computer Software clause at DFARS 252.227-7013, and/or in similar or
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** successor clauses in the FAR, DOD or NASA FAR Supplement. Unpublished -
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** rights reserved under the Copyright Laws of the United States.
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**
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** Author: Eric Veach, July 1994.
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*/
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/* Use #define's so that another heap implementation can use this one */
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#define PQkey PQHeapKey
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#define PQhandle PQHeapHandle
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#define PriorityQ PriorityQHeap
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#define pqNewPriorityQ(leq) __gl_pqHeapNewPriorityQ(leq)
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#define pqDeletePriorityQ(pq) __gl_pqHeapDeletePriorityQ(pq)
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/* The basic operations are insertion of a new key (pqInsert),
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* and examination/extraction of a key whose value is minimum
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* (pqMinimum/pqExtractMin). Deletion is also allowed (pqDelete);
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* for this purpose pqInsert returns a "handle" which is supplied
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* as the argument.
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*
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* An initial heap may be created efficiently by calling pqInsert
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* repeatedly, then calling pqInit. In any case pqInit must be called
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* before any operations other than pqInsert are used.
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*
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* If the heap is empty, pqMinimum/pqExtractMin will return a NULL key.
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* This may also be tested with pqIsEmpty.
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*/
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#define pqInit(pq) __gl_pqHeapInit(pq)
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#define pqInsert(pq,key) __gl_pqHeapInsert(pq,key)
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#define pqMinimum(pq) __gl_pqHeapMinimum(pq)
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#define pqExtractMin(pq) __gl_pqHeapExtractMin(pq)
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#define pqDelete(pq,handle) __gl_pqHeapDelete(pq,handle)
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#define pqIsEmpty(pq) __gl_pqHeapIsEmpty(pq)
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/* Since we support deletion the data structure is a little more
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* complicated than an ordinary heap. "nodes" is the heap itself;
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* active nodes are stored in the range 1..pq->size. When the
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* heap exceeds its allocated size (pq->max), its size doubles.
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* The children of node i are nodes 2i and 2i+1.
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*
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* Each node stores an index into an array "handles". Each handle
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* stores a key, plus a pointer back to the node which currently
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* represents that key (ie. nodes[handles[i].node].handle == i).
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*/
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typedef void *PQkey;
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typedef long PQhandle;
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typedef struct PriorityQ PriorityQ;
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typedef struct { PQhandle handle; } PQnode;
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typedef struct { PQkey key; PQhandle node; } PQhandleElem;
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struct PriorityQ {
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PQnode *nodes;
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PQhandleElem *handles;
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long size, max;
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PQhandle freeList;
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int initialized;
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int (*leq)(PQkey key1, PQkey key2);
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};
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PriorityQ *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) );
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void pqDeletePriorityQ( PriorityQ *pq );
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void pqInit( PriorityQ *pq );
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PQhandle pqInsert( PriorityQ *pq, PQkey key );
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PQkey pqExtractMin( PriorityQ *pq );
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void pqDelete( PriorityQ *pq, PQhandle handle );
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#define __gl_pqHeapMinimum(pq) ((pq)->handles[(pq)->nodes[1].handle].key)
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#define __gl_pqHeapIsEmpty(pq) ((pq)->size == 0)
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#endif
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