1/*
2 * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
3 * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice including the dates of first publication and
13 * either this permission notice or a reference to
14 * http://oss.sgi.com/projects/FreeB/
15 * shall be included in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
21 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
22 * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23 * SOFTWARE.
24 *
25 * Except as contained in this notice, the name of Silicon Graphics, Inc.
26 * shall not be used in advertising or otherwise to promote the sale, use or
27 * other dealings in this Software without prior written authorization from
28 * Silicon Graphics, Inc.
29 */
30/*
31** Author: Eric Veach, July 1994.
32**
33*/
34
35#include "gluos.h"
36#include <stddef.h>
37#include <assert.h>
38#include <limits.h>		/* LONG_MAX */
39#include "memalloc.h"
40
41/* Include all the code for the regular heap-based queue here. */
42
43#include "priorityq-heap.c"
44
45/* Now redefine all the function names to map to their "Sort" versions. */
46
47#include "priorityq-sort.h"
48
49/* really __gl_pqSortNewPriorityQ */
50PriorityQ *pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) )
51{
52  PriorityQ *pq = (PriorityQ *)memAlloc( sizeof( PriorityQ ));
53  if (pq == NULL) return NULL;
54
55  pq->heap = __gl_pqHeapNewPriorityQ( leq );
56  if (pq->heap == NULL) {
57     memFree(pq);
58     return NULL;
59  }
60
61  pq->keys = (PQHeapKey *)memAlloc( INIT_SIZE * sizeof(pq->keys[0]) );
62  if (pq->keys == NULL) {
63     __gl_pqHeapDeletePriorityQ(pq->heap);
64     memFree(pq);
65     return NULL;
66  }
67
68  pq->order = NULL;
69  pq->size = 0;
70  pq->max = INIT_SIZE;
71  pq->initialized = FALSE;
72  pq->leq = leq;
73  return pq;
74}
75
76/* really __gl_pqSortDeletePriorityQ */
77void pqDeletePriorityQ( PriorityQ *pq )
78{
79  assert(pq != NULL);
80  if (pq->heap != NULL) __gl_pqHeapDeletePriorityQ( pq->heap );
81  if (pq->order != NULL) memFree( pq->order );
82  if (pq->keys != NULL) memFree( pq->keys );
83  memFree( pq );
84}
85
86
87#define LT(x,y)		(! LEQ(y,x))
88#define GT(x,y)		(! LEQ(x,y))
89#define Swap(a,b)	do{PQkey *tmp = *a; *a = *b; *b = tmp;}while(0)
90
91/* really __gl_pqSortInit */
92int pqInit( PriorityQ *pq )
93{
94  PQkey **p, **r, **i, **j, *piv;
95  struct { PQkey **p, **r; } Stack[50], *top = Stack;
96  unsigned long seed = 2016473283;
97
98  /* Create an array of indirect pointers to the keys, so that we
99   * the handles we have returned are still valid.
100   */
101/*
102  pq->order = (PQHeapKey **)memAlloc( (size_t)
103                                  (pq->size * sizeof(pq->order[0])) );
104*/
105  pq->order = (PQHeapKey **)memAlloc( (size_t)
106                                  ((pq->size+1) * sizeof(pq->order[0])) );
107/* the previous line is a patch to compensate for the fact that IBM */
108/* machines return a null on a malloc of zero bytes (unlike SGI),   */
109/* so we have to put in this defense to guard against a memory      */
110/* fault four lines down. from fossum@austin.ibm.com.               */
111  if (pq->order == NULL) return 0;
112
113  p = pq->order;
114  r = p + pq->size - 1;
115  for( piv = pq->keys, i = p; i <= r; ++piv, ++i ) {
116    *i = piv;
117  }
118
119  /* Sort the indirect pointers in descending order,
120   * using randomized Quicksort
121   */
122  top->p = p; top->r = r; ++top;
123  while( --top >= Stack ) {
124    p = top->p;
125    r = top->r;
126    while( r > p + 10 ) {
127      seed = seed * 1539415821 + 1;
128      i = p + seed % (r - p + 1);
129      piv = *i;
130      *i = *p;
131      *p = piv;
132      i = p - 1;
133      j = r + 1;
134      do {
135	do { ++i; } while( GT( **i, *piv ));
136	do { --j; } while( LT( **j, *piv ));
137	Swap( i, j );
138      } while( i < j );
139      Swap( i, j );	/* Undo last swap */
140      if( i - p < r - j ) {
141	top->p = j+1; top->r = r; ++top;
142	r = i-1;
143      } else {
144	top->p = p; top->r = i-1; ++top;
145	p = j+1;
146      }
147    }
148    /* Insertion sort small lists */
149    for( i = p+1; i <= r; ++i ) {
150      piv = *i;
151      for( j = i; j > p && LT( **(j-1), *piv ); --j ) {
152	*j = *(j-1);
153      }
154      *j = piv;
155    }
156  }
157  pq->max = pq->size;
158  pq->initialized = TRUE;
159  __gl_pqHeapInit( pq->heap );	/* always succeeds */
160
161#ifndef NDEBUG
162  p = pq->order;
163  r = p + pq->size - 1;
164  for( i = p; i < r; ++i ) {
165    assert( LEQ( **(i+1), **i ));
166  }
167#endif
168
169  return 1;
170}
171
172/* really __gl_pqSortInsert */
173/* returns LONG_MAX iff out of memory */
174PQhandle pqInsert( PriorityQ *pq, PQkey keyNew )
175{
176  long curr;
177
178  if( pq->initialized ) {
179    return __gl_pqHeapInsert( pq->heap, keyNew );
180  }
181  curr = pq->size;
182  if( ++ pq->size >= pq->max ) {
183    PQkey *saveKey= pq->keys;
184
185    /* If the heap overflows, double its size. */
186    pq->max <<= 1;
187    pq->keys = (PQHeapKey *)memRealloc( pq->keys,
188	 	                        (size_t)
189	                                 (pq->max * sizeof( pq->keys[0] )));
190    if (pq->keys == NULL) {
191       pq->keys = saveKey;	/* restore ptr to free upon return */
192       return LONG_MAX;
193    }
194  }
195  assert(curr != LONG_MAX);
196  pq->keys[curr] = keyNew;
197
198  /* Negative handles index the sorted array. */
199  return -(curr+1);
200}
201
202/* really __gl_pqSortExtractMin */
203PQkey pqExtractMin( PriorityQ *pq )
204{
205  PQkey sortMin, heapMin;
206
207  if( pq->size == 0 ) {
208    return __gl_pqHeapExtractMin( pq->heap );
209  }
210  sortMin = *(pq->order[pq->size-1]);
211  if( ! __gl_pqHeapIsEmpty( pq->heap )) {
212    heapMin = __gl_pqHeapMinimum( pq->heap );
213    if( LEQ( heapMin, sortMin )) {
214      return __gl_pqHeapExtractMin( pq->heap );
215    }
216  }
217  do {
218    -- pq->size;
219  } while( pq->size > 0 && *(pq->order[pq->size-1]) == NULL );
220  return sortMin;
221}
222
223/* really __gl_pqSortMinimum */
224PQkey pqMinimum( PriorityQ *pq )
225{
226  PQkey sortMin, heapMin;
227
228  if( pq->size == 0 ) {
229    return __gl_pqHeapMinimum( pq->heap );
230  }
231  sortMin = *(pq->order[pq->size-1]);
232  if( ! __gl_pqHeapIsEmpty( pq->heap )) {
233    heapMin = __gl_pqHeapMinimum( pq->heap );
234    if( LEQ( heapMin, sortMin )) {
235      return heapMin;
236    }
237  }
238  return sortMin;
239}
240
241/* really __gl_pqSortIsEmpty */
242int pqIsEmpty( PriorityQ *pq )
243{
244  return (pq->size == 0) && __gl_pqHeapIsEmpty( pq->heap );
245}
246
247/* really __gl_pqSortDelete */
248void pqDelete( PriorityQ *pq, PQhandle curr )
249{
250  if( curr >= 0 ) {
251    __gl_pqHeapDelete( pq->heap, curr );
252    return;
253  }
254  curr = -(curr+1);
255  assert( curr < pq->max && pq->keys[curr] != NULL );
256
257  pq->keys[curr] = NULL;
258  while( pq->size > 0 && *(pq->order[pq->size-1]) == NULL ) {
259    -- pq->size;
260  }
261}
262