aboutsummaryrefslogtreecommitdiff
path: root/libtess/priorityq.c
diff options
context:
space:
mode:
Diffstat (limited to 'libtess/priorityq.c')
-rw-r--r--libtess/priorityq.c267
1 files changed, 267 insertions, 0 deletions
diff --git a/libtess/priorityq.c b/libtess/priorityq.c
new file mode 100644
index 0000000..8744edb
--- /dev/null
+++ b/libtess/priorityq.c
@@ -0,0 +1,267 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+**
+*/
+/*
+** Author: Eric Veach, July 1994.
+**
+** $Date$ $Revision$
+** $Header$
+*/
+
+#include "gluos.h"
+#include <stddef.h>
+#include <assert.h>
+#include <limits.h> /* LONG_MAX */
+#include "memalloc.h"
+
+/* Include all the code for the regular heap-based queue here. */
+
+#include "priorityq-heap.c"
+
+/* Now redefine all the function names to map to their "Sort" versions. */
+
+#include "priorityq-sort.h"
+
+/* really __gl_pqSortNewPriorityQ */
+PriorityQ *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) )
+{
+ PriorityQ *pq = (PriorityQ *)memAlloc( sizeof( PriorityQ ));
+ if (pq == NULL) return NULL;
+
+ pq->heap = __gl_pqHeapNewPriorityQ( leq );
+ if (pq->heap == NULL) {
+ memFree(pq);
+ return NULL;
+ }
+
+ pq->keys = (PQHeapKey *)memAlloc( INIT_SIZE * sizeof(pq->keys[0]) );
+ if (pq->keys == NULL) {
+ __gl_pqHeapDeletePriorityQ(pq->heap);
+ memFree(pq);
+ return NULL;
+ }
+
+ pq->size = 0;
+ pq->max = INIT_SIZE;
+ pq->initialized = FALSE;
+ pq->leq = leq;
+ return pq;
+}
+
+/* really __gl_pqSortDeletePriorityQ */
+void pqDeletePriorityQ( PriorityQ *pq )
+{
+ assert(pq != NULL);
+ if (pq->heap != NULL) __gl_pqHeapDeletePriorityQ( pq->heap );
+ if (pq->order != NULL) memFree( pq->order );
+ if (pq->keys != NULL) memFree( pq->keys );
+ memFree( pq );
+}
+
+
+#define LT(x,y) (! LEQ(y,x))
+#define GT(x,y) (! LEQ(x,y))
+#define Swap(a,b) if(1){PQkey *tmp = *a; *a = *b; *b = tmp;}else
+
+/* really __gl_pqSortInit */
+int pqInit( PriorityQ *pq )
+{
+ PQkey **p, **r, **i, **j, *piv;
+ struct { PQkey **p, **r; } Stack[50], *top = Stack;
+ unsigned long seed = 2016473283;
+
+ /* Create an array of indirect pointers to the keys, so that we
+ * the handles we have returned are still valid.
+ */
+/*
+ pq->order = (PQHeapKey **)memAlloc( (size_t)
+ (pq->size * sizeof(pq->order[0])) );
+*/
+ pq->order = (PQHeapKey **)memAlloc( (size_t)
+ ((pq->size+1) * sizeof(pq->order[0])) );
+/* the previous line is a patch to compensate for the fact that IBM */
+/* machines return a null on a malloc of zero bytes (unlike SGI), */
+/* so we have to put in this defense to guard against a memory */
+/* fault four lines down. from fossum@austin.ibm.com. */
+ if (pq->order == NULL) return 0;
+
+ p = pq->order;
+ r = p + pq->size - 1;
+ for( piv = pq->keys, i = p; i <= r; ++piv, ++i ) {
+ *i = piv;
+ }
+
+ /* Sort the indirect pointers in descending order,
+ * using randomized Quicksort
+ */
+ top->p = p; top->r = r; ++top;
+ while( --top >= Stack ) {
+ p = top->p;
+ r = top->r;
+ while( r > p + 10 ) {
+ seed = seed * 1539415821 + 1;
+ i = p + seed % (r - p + 1);
+ piv = *i;
+ *i = *p;
+ *p = piv;
+ i = p - 1;
+ j = r + 1;
+ do {
+ do { ++i; } while( GT( **i, *piv ));
+ do { --j; } while( LT( **j, *piv ));
+ Swap( i, j );
+ } while( i < j );
+ Swap( i, j ); /* Undo last swap */
+ if( i - p < r - j ) {
+ top->p = j+1; top->r = r; ++top;
+ r = i-1;
+ } else {
+ top->p = p; top->r = i-1; ++top;
+ p = j+1;
+ }
+ }
+ /* Insertion sort small lists */
+ for( i = p+1; i <= r; ++i ) {
+ piv = *i;
+ for( j = i; j > p && LT( **(j-1), *piv ); --j ) {
+ *j = *(j-1);
+ }
+ *j = piv;
+ }
+ }
+ pq->max = pq->size;
+ pq->initialized = TRUE;
+ __gl_pqHeapInit( pq->heap ); /* always succeeds */
+
+#ifndef NDEBUG
+ p = pq->order;
+ r = p + pq->size - 1;
+ for( i = p; i < r; ++i ) {
+ assert( LEQ( **(i+1), **i ));
+ }
+#endif
+
+ return 1;
+}
+
+/* really __gl_pqSortInsert */
+/* returns LONG_MAX iff out of memory */
+PQhandle pqInsert( PriorityQ *pq, PQkey keyNew )
+{
+ long curr;
+
+ if( pq->initialized ) {
+ return __gl_pqHeapInsert( pq->heap, keyNew );
+ }
+ curr = pq->size;
+ if( ++ pq->size >= pq->max ) {
+ PQkey *saveKey= pq->keys;
+
+ /* If the heap overflows, double its size. */
+ pq->max <<= 1;
+ pq->keys = (PQHeapKey *)memRealloc( pq->keys,
+ (size_t)
+ (pq->max * sizeof( pq->keys[0] )));
+ if (pq->keys == NULL) {
+ pq->keys = saveKey; /* restore ptr to free upon return */
+ return LONG_MAX;
+ }
+ }
+ assert(curr != LONG_MAX);
+ pq->keys[curr] = keyNew;
+
+ /* Negative handles index the sorted array. */
+ return -(curr+1);
+}
+
+/* really __gl_pqSortExtractMin */
+PQkey pqExtractMin( PriorityQ *pq )
+{
+ PQkey sortMin, heapMin;
+
+ if( pq->size == 0 ) {
+ return __gl_pqHeapExtractMin( pq->heap );
+ }
+ sortMin = *(pq->order[pq->size-1]);
+ if( ! __gl_pqHeapIsEmpty( pq->heap )) {
+ heapMin = __gl_pqHeapMinimum( pq->heap );
+ if( LEQ( heapMin, sortMin )) {
+ return __gl_pqHeapExtractMin( pq->heap );
+ }
+ }
+ do {
+ -- pq->size;
+ } while( pq->size > 0 && *(pq->order[pq->size-1]) == NULL );
+ return sortMin;
+}
+
+/* really __gl_pqSortMinimum */
+PQkey pqMinimum( PriorityQ *pq )
+{
+ PQkey sortMin, heapMin;
+
+ if( pq->size == 0 ) {
+ return __gl_pqHeapMinimum( pq->heap );
+ }
+ sortMin = *(pq->order[pq->size-1]);
+ if( ! __gl_pqHeapIsEmpty( pq->heap )) {
+ heapMin = __gl_pqHeapMinimum( pq->heap );
+ if( LEQ( heapMin, sortMin )) {
+ return heapMin;
+ }
+ }
+ return sortMin;
+}
+
+/* really __gl_pqSortIsEmpty */
+int pqIsEmpty( PriorityQ *pq )
+{
+ return (pq->size == 0) && __gl_pqHeapIsEmpty( pq->heap );
+}
+
+/* really __gl_pqSortDelete */
+void pqDelete( PriorityQ *pq, PQhandle curr )
+{
+ if( curr >= 0 ) {
+ __gl_pqHeapDelete( pq->heap, curr );
+ return;
+ }
+ curr = -(curr+1);
+ assert( curr < pq->max && pq->keys[curr] != NULL );
+
+ pq->keys[curr] = NULL;
+ while( pq->size > 0 && *(pq->order[pq->size-1]) == NULL ) {
+ -- pq->size;
+ }
+}
generated by cgit v1.1 at 2024-07-01 10:58:13 +0000