| /* |
| * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008) |
| * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved. |
| * |
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| * 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 |
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| * Except as contained in this notice, the name of Silicon Graphics, Inc. |
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| * Silicon Graphics, Inc. |
| */ |
| /* |
| ** Author: Eric Veach, July 1994. |
| ** |
| ** $Date: 2012/03/29 17:22:17 $ $Revision: 1.1.1.1 $ |
| ** $Header: /cvs/bao-parsec/pkgs/libs/mesa/src/src/glu/sgi/libtess/priorityq-heap.c,v 1.1.1.1 2012/03/29 17:22:17 uid42307 Exp $ |
| */ |
| |
| #include <stddef.h> |
| #include <assert.h> |
| #include "priorityq-heap.h" |
| #include "memalloc.h" |
| |
| #define INIT_SIZE 32 |
| |
| #define TRUE 1 |
| #define FALSE 0 |
| |
| #ifdef FOR_TRITE_TEST_PROGRAM |
| #define LEQ(x,y) (*pq->leq)(x,y) |
| #else |
| /* Violates modularity, but a little faster */ |
| #include "geom.h" |
| #define LEQ(x,y) VertLeq((GLUvertex *)x, (GLUvertex *)y) |
| #endif |
| |
| /* really __gl_pqHeapNewPriorityQ */ |
| PriorityQ *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) ) |
| { |
| PriorityQ *pq = (PriorityQ *)memAlloc( sizeof( PriorityQ )); |
| if (pq == NULL) return NULL; |
| |
| pq->size = 0; |
| pq->max = INIT_SIZE; |
| pq->nodes = (PQnode *)memAlloc( (INIT_SIZE + 1) * sizeof(pq->nodes[0]) ); |
| if (pq->nodes == NULL) { |
| memFree(pq); |
| return NULL; |
| } |
| |
| pq->handles = (PQhandleElem *)memAlloc( (INIT_SIZE + 1) * sizeof(pq->handles[0]) ); |
| if (pq->handles == NULL) { |
| memFree(pq->nodes); |
| memFree(pq); |
| return NULL; |
| } |
| |
| pq->initialized = FALSE; |
| pq->freeList = 0; |
| pq->leq = leq; |
| |
| pq->nodes[1].handle = 1; /* so that Minimum() returns NULL */ |
| pq->handles[1].key = NULL; |
| return pq; |
| } |
| |
| /* really __gl_pqHeapDeletePriorityQ */ |
| void pqDeletePriorityQ( PriorityQ *pq ) |
| { |
| memFree( pq->handles ); |
| memFree( pq->nodes ); |
| memFree( pq ); |
| } |
| |
| |
| static void FloatDown( PriorityQ *pq, long curr ) |
| { |
| PQnode *n = pq->nodes; |
| PQhandleElem *h = pq->handles; |
| PQhandle hCurr, hChild; |
| long child; |
| |
| hCurr = n[curr].handle; |
| for( ;; ) { |
| child = curr << 1; |
| if( child < pq->size && LEQ( h[n[child+1].handle].key, |
| h[n[child].handle].key )) { |
| ++child; |
| } |
| |
| assert(child <= pq->max); |
| |
| hChild = n[child].handle; |
| if( child > pq->size || LEQ( h[hCurr].key, h[hChild].key )) { |
| n[curr].handle = hCurr; |
| h[hCurr].node = curr; |
| break; |
| } |
| n[curr].handle = hChild; |
| h[hChild].node = curr; |
| curr = child; |
| } |
| } |
| |
| |
| static void FloatUp( PriorityQ *pq, long curr ) |
| { |
| PQnode *n = pq->nodes; |
| PQhandleElem *h = pq->handles; |
| PQhandle hCurr, hParent; |
| long parent; |
| |
| hCurr = n[curr].handle; |
| for( ;; ) { |
| parent = curr >> 1; |
| hParent = n[parent].handle; |
| if( parent == 0 || LEQ( h[hParent].key, h[hCurr].key )) { |
| n[curr].handle = hCurr; |
| h[hCurr].node = curr; |
| break; |
| } |
| n[curr].handle = hParent; |
| h[hParent].node = curr; |
| curr = parent; |
| } |
| } |
| |
| /* really __gl_pqHeapInit */ |
| void pqInit( PriorityQ *pq ) |
| { |
| long i; |
| |
| /* This method of building a heap is O(n), rather than O(n lg n). */ |
| |
| for( i = pq->size; i >= 1; --i ) { |
| FloatDown( pq, i ); |
| } |
| pq->initialized = TRUE; |
| } |
| |
| /* really __gl_pqHeapInsert */ |
| /* returns LONG_MAX iff out of memory */ |
| PQhandle pqInsert( PriorityQ *pq, PQkey keyNew ) |
| { |
| long curr; |
| PQhandle free; |
| |
| curr = ++ pq->size; |
| if( (curr*2) > pq->max ) { |
| PQnode *saveNodes= pq->nodes; |
| PQhandleElem *saveHandles= pq->handles; |
| |
| /* If the heap overflows, double its size. */ |
| pq->max <<= 1; |
| pq->nodes = (PQnode *)memRealloc( pq->nodes, |
| (size_t) |
| ((pq->max + 1) * sizeof( pq->nodes[0] ))); |
| if (pq->nodes == NULL) { |
| pq->nodes = saveNodes; /* restore ptr to free upon return */ |
| return LONG_MAX; |
| } |
| pq->handles = (PQhandleElem *)memRealloc( pq->handles, |
| (size_t) |
| ((pq->max + 1) * |
| sizeof( pq->handles[0] ))); |
| if (pq->handles == NULL) { |
| pq->handles = saveHandles; /* restore ptr to free upon return */ |
| return LONG_MAX; |
| } |
| } |
| |
| if( pq->freeList == 0 ) { |
| free = curr; |
| } else { |
| free = pq->freeList; |
| pq->freeList = pq->handles[free].node; |
| } |
| |
| pq->nodes[curr].handle = free; |
| pq->handles[free].node = curr; |
| pq->handles[free].key = keyNew; |
| |
| if( pq->initialized ) { |
| FloatUp( pq, curr ); |
| } |
| assert(free != LONG_MAX); |
| return free; |
| } |
| |
| /* really __gl_pqHeapExtractMin */ |
| PQkey pqExtractMin( PriorityQ *pq ) |
| { |
| PQnode *n = pq->nodes; |
| PQhandleElem *h = pq->handles; |
| PQhandle hMin = n[1].handle; |
| PQkey min = h[hMin].key; |
| |
| if( pq->size > 0 ) { |
| n[1].handle = n[pq->size].handle; |
| h[n[1].handle].node = 1; |
| |
| h[hMin].key = NULL; |
| h[hMin].node = pq->freeList; |
| pq->freeList = hMin; |
| |
| if( -- pq->size > 0 ) { |
| FloatDown( pq, 1 ); |
| } |
| } |
| return min; |
| } |
| |
| /* really __gl_pqHeapDelete */ |
| void pqDelete( PriorityQ *pq, PQhandle hCurr ) |
| { |
| PQnode *n = pq->nodes; |
| PQhandleElem *h = pq->handles; |
| long curr; |
| |
| assert( hCurr >= 1 && hCurr <= pq->max && h[hCurr].key != NULL ); |
| |
| curr = h[hCurr].node; |
| n[curr].handle = n[pq->size].handle; |
| h[n[curr].handle].node = curr; |
| |
| if( curr <= -- pq->size ) { |
| if( curr <= 1 || LEQ( h[n[curr>>1].handle].key, h[n[curr].handle].key )) { |
| FloatDown( pq, curr ); |
| } else { |
| FloatUp( pq, curr ); |
| } |
| } |
| h[hCurr].key = NULL; |
| h[hCurr].node = pq->freeList; |
| pq->freeList = hCurr; |
| } |