SGI SI GLU library

1 files changed, 259 insertions, 0 deletions

diff --git a/src/glu/sgi/libtess/priorityq-heap.c b/src/glu/sgi/libtess/priorityq-heap.c
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+/*
+** 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: 2001/03/17 00:25:41 $ $Revision: 1.1 $
+** $Header: /home/krh/git/sync/mesa-cvs-repo/Mesa/src/glu/sgi/libtess/priorityq-heap.c,v 1.1 2001/03/17 00:25:41 brianp 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;
+}