262 lines
7.0 KiB
C
262 lines
7.0 KiB
C
/*
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* SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
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* Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice including the dates of first publication and
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* either this permission notice or a reference to
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* http://oss.sgi.com/projects/FreeB/
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* shall be included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
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* OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* Except as contained in this notice, the name of Silicon Graphics, Inc.
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* shall not be used in advertising or otherwise to promote the sale, use or
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* other dealings in this Software without prior written authorization from
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* Silicon Graphics, Inc.
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*/
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/*
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** Author: Eric Veach, July 1994.
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**
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*/
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#include "gluos.h"
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#include <stddef.h>
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#include <assert.h>
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#include <limits.h> /* LONG_MAX */
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#include "memalloc.h"
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/* Include all the code for the regular heap-based queue here. */
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#include "priorityq-heap.c"
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/* Now redefine all the function names to map to their "Sort" versions. */
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#include "priorityq-sort.h"
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/* really __gl_pqSortNewPriorityQ */
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PriorityQ *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) )
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{
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PriorityQ *pq = (PriorityQ *)memAlloc( sizeof( PriorityQ ));
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if (pq == NULL) return NULL;
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pq->heap = __gl_pqHeapNewPriorityQ( leq );
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if (pq->heap == NULL) {
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memFree(pq);
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return NULL;
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}
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pq->keys = (PQHeapKey *)memAlloc( INIT_SIZE * sizeof(pq->keys[0]) );
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if (pq->keys == NULL) {
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__gl_pqHeapDeletePriorityQ(pq->heap);
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memFree(pq);
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return NULL;
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}
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pq->order = NULL;
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pq->size = 0;
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pq->max = INIT_SIZE;
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pq->initialized = FALSE;
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pq->leq = leq;
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return pq;
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}
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/* really __gl_pqSortDeletePriorityQ */
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void pqDeletePriorityQ( PriorityQ *pq )
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{
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assert(pq != NULL);
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if (pq->heap != NULL) __gl_pqHeapDeletePriorityQ( pq->heap );
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if (pq->order != NULL) memFree( pq->order );
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if (pq->keys != NULL) memFree( pq->keys );
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memFree( pq );
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}
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#define LT(x,y) (! LEQ(y,x))
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#define GT(x,y) (! LEQ(x,y))
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#define Swap(a,b) do{PQkey *tmp = *a; *a = *b; *b = tmp;}while(0)
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/* really __gl_pqSortInit */
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int pqInit( PriorityQ *pq )
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{
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PQkey **p, **r, **i, **j, *piv;
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struct { PQkey **p, **r; } Stack[50], *top = Stack;
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unsigned long seed = 2016473283;
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/* Create an array of indirect pointers to the keys, so that we
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* the handles we have returned are still valid.
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*/
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/*
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pq->order = (PQHeapKey **)memAlloc( (size_t)
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(pq->size * sizeof(pq->order[0])) );
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*/
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pq->order = (PQHeapKey **)memAlloc( (size_t)
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((pq->size+1) * sizeof(pq->order[0])) );
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/* the previous line is a patch to compensate for the fact that IBM */
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/* machines return a null on a malloc of zero bytes (unlike SGI), */
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/* so we have to put in this defense to guard against a memory */
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/* fault four lines down. from fossum@austin.ibm.com. */
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if (pq->order == NULL) return 0;
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p = pq->order;
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r = p + pq->size - 1;
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for( piv = pq->keys, i = p; i <= r; ++piv, ++i ) {
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*i = piv;
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}
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/* Sort the indirect pointers in descending order,
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* using randomized Quicksort
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*/
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top->p = p; top->r = r; ++top;
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while( --top >= Stack ) {
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p = top->p;
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r = top->r;
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while( r > p + 10 ) {
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seed = seed * 1539415821 + 1;
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i = p + seed % (r - p + 1);
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piv = *i;
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*i = *p;
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*p = piv;
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i = p - 1;
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j = r + 1;
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do {
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do { ++i; } while( GT( **i, *piv ));
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do { --j; } while( LT( **j, *piv ));
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Swap( i, j );
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} while( i < j );
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Swap( i, j ); /* Undo last swap */
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if( i - p < r - j ) {
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top->p = j+1; top->r = r; ++top;
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r = i-1;
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} else {
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top->p = p; top->r = i-1; ++top;
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p = j+1;
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}
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}
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/* Insertion sort small lists */
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for( i = p+1; i <= r; ++i ) {
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piv = *i;
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for( j = i; j > p && LT( **(j-1), *piv ); --j ) {
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*j = *(j-1);
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}
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*j = piv;
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}
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}
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pq->max = pq->size;
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pq->initialized = TRUE;
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__gl_pqHeapInit( pq->heap ); /* always succeeds */
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#ifndef NDEBUG
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p = pq->order;
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r = p + pq->size - 1;
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for( i = p; i < r; ++i ) {
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assert( LEQ( **(i+1), **i ));
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}
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#endif
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return 1;
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}
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/* really __gl_pqSortInsert */
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/* returns LONG_MAX iff out of memory */
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PQhandle pqInsert( PriorityQ *pq, PQkey keyNew )
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{
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long curr;
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if( pq->initialized ) {
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return __gl_pqHeapInsert( pq->heap, keyNew );
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}
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curr = pq->size;
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if( ++ pq->size >= pq->max ) {
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PQkey *saveKey= pq->keys;
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/* If the heap overflows, double its size. */
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pq->max <<= 1;
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pq->keys = (PQHeapKey *)memRealloc( pq->keys,
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(size_t)
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(pq->max * sizeof( pq->keys[0] )));
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if (pq->keys == NULL) {
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pq->keys = saveKey; /* restore ptr to free upon return */
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return LONG_MAX;
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}
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}
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assert(curr != LONG_MAX);
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pq->keys[curr] = keyNew;
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/* Negative handles index the sorted array. */
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return -(curr+1);
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}
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/* really __gl_pqSortExtractMin */
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PQkey pqExtractMin( PriorityQ *pq )
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{
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PQkey sortMin, heapMin;
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if( pq->size == 0 ) {
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return __gl_pqHeapExtractMin( pq->heap );
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}
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sortMin = *(pq->order[pq->size-1]);
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if( ! __gl_pqHeapIsEmpty( pq->heap )) {
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heapMin = __gl_pqHeapMinimum( pq->heap );
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if( LEQ( heapMin, sortMin )) {
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return __gl_pqHeapExtractMin( pq->heap );
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}
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}
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do {
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-- pq->size;
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} while( pq->size > 0 && *(pq->order[pq->size-1]) == NULL );
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return sortMin;
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}
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/* really __gl_pqSortMinimum */
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PQkey pqMinimum( PriorityQ *pq )
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{
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PQkey sortMin, heapMin;
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if( pq->size == 0 ) {
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return __gl_pqHeapMinimum( pq->heap );
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}
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sortMin = *(pq->order[pq->size-1]);
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if( ! __gl_pqHeapIsEmpty( pq->heap )) {
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heapMin = __gl_pqHeapMinimum( pq->heap );
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if( LEQ( heapMin, sortMin )) {
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return heapMin;
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}
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}
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return sortMin;
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}
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/* really __gl_pqSortIsEmpty */
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int pqIsEmpty( PriorityQ *pq )
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{
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return (pq->size == 0) && __gl_pqHeapIsEmpty( pq->heap );
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}
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/* really __gl_pqSortDelete */
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void pqDelete( PriorityQ *pq, PQhandle curr )
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{
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if( curr >= 0 ) {
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__gl_pqHeapDelete( pq->heap, curr );
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return;
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}
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curr = -(curr+1);
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assert( curr < pq->max && pq->keys[curr] != NULL );
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pq->keys[curr] = NULL;
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while( pq->size > 0 && *(pq->order[pq->size-1]) == NULL ) {
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-- pq->size;
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}
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}
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