mutter/cogl/cogl-path/tesselator/priorityq-heap.h
2016-04-22 16:44:31 +02:00

108 lines
4.0 KiB
C

/*
* SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
* Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice including the dates of first publication and
* either this permission notice or a reference to
* http://oss.sgi.com/projects/FreeB/
* shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
* OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* Except as contained in this notice, the name of Silicon Graphics, Inc.
* shall not be used in advertising or otherwise to promote the sale, use or
* other dealings in this Software without prior written authorization from
* Silicon Graphics, Inc.
*/
/*
** Author: Eric Veach, July 1994.
**
*/
#ifndef __priorityq_heap_h_
#define __priorityq_heap_h_
/* Use #define's so that another heap implementation can use this one */
#define PQkey PQHeapKey
#define PQhandle PQHeapHandle
#define PriorityQ PriorityQHeap
#define pqNewPriorityQ(leq) __gl_pqHeapNewPriorityQ(leq)
#define pqDeletePriorityQ(pq) __gl_pqHeapDeletePriorityQ(pq)
/* The basic operations are insertion of a new key (pqInsert),
* and examination/extraction of a key whose value is minimum
* (pqMinimum/pqExtractMin). Deletion is also allowed (pqDelete);
* for this purpose pqInsert returns a "handle" which is supplied
* as the argument.
*
* An initial heap may be created efficiently by calling pqInsert
* repeatedly, then calling pqInit. In any case pqInit must be called
* before any operations other than pqInsert are used.
*
* If the heap is empty, pqMinimum/pqExtractMin will return a NULL key.
* This may also be tested with pqIsEmpty.
*/
#define pqInit(pq) __gl_pqHeapInit(pq)
#define pqInsert(pq,key) __gl_pqHeapInsert(pq,key)
#define pqMinimum(pq) __gl_pqHeapMinimum(pq)
#define pqExtractMin(pq) __gl_pqHeapExtractMin(pq)
#define pqDelete(pq,handle) __gl_pqHeapDelete(pq,handle)
#define pqIsEmpty(pq) __gl_pqHeapIsEmpty(pq)
/* Since we support deletion the data structure is a little more
* complicated than an ordinary heap. "nodes" is the heap itself;
* active nodes are stored in the range 1..pq->size. When the
* heap exceeds its allocated size (pq->max), its size doubles.
* The children of node i are nodes 2i and 2i+1.
*
* Each node stores an index into an array "handles". Each handle
* stores a key, plus a pointer back to the node which currently
* represents that key (ie. nodes[handles[i].node].handle == i).
*/
typedef void *PQkey;
typedef long PQhandle;
typedef struct PriorityQ PriorityQ;
typedef struct { PQhandle handle; } PQnode;
typedef struct { PQkey key; PQhandle node; } PQhandleElem;
struct PriorityQ {
PQnode *nodes;
PQhandleElem *handles;
long size, max;
PQhandle freeList;
int initialized;
int (*leq)(PQkey key1, PQkey key2);
};
PriorityQ *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) );
void pqDeletePriorityQ( PriorityQ *pq );
void pqInit( PriorityQ *pq );
PQhandle pqInsert( PriorityQ *pq, PQkey key );
PQkey pqExtractMin( PriorityQ *pq );
void pqDelete( PriorityQ *pq, PQhandle handle );
#define __gl_pqHeapMinimum(pq) ((pq)->handles[(pq)->nodes[1].handle].key)
#define __gl_pqHeapIsEmpty(pq) ((pq)->size == 0)
#endif