summaryrefslogtreecommitdiffstats
path: root/src/H5HL.c
blob: 09df1cbf82f825bcab6a288c548463b10acc6da6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the files COPYING and Copyright.html.  COPYING can be found at the root   *
 * of the source code distribution tree; Copyright.html can be found at the  *
 * root level of an installed copy of the electronic HDF5 document set and   *
 * is linked from the top-level documents page.  It can also be found at     *
 * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
 * access to either file, you may request a copy from help@hdfgroup.org.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*-------------------------------------------------------------------------
 *
 * Created:		H5HL.c
 *			Jul 16 1997
 *			Robb Matzke <matzke@llnl.gov>
 *
 * Purpose:		Heap functions for the local heaps used by symbol
 *			tables to store names (among other things).
 *
 *-------------------------------------------------------------------------
 */

/****************/
/* Module Setup */
/****************/

#define H5F_PACKAGE		/* Suppress error about including H5Fpkg  */
#define H5HL_PACKAGE		/* Suppress error about including H5HLpkg */


/***********/
/* Headers */
/***********/
#include "H5private.h"		/* Generic Functions			*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Fpkg.h"             /* File access				*/
#include "H5HLpkg.h"		/* Local Heaps				*/
#include "H5MFprivate.h"	/* File memory management		*/


/****************/
/* Local Macros */
/****************/

#define H5HL_MIN_HEAP   128             /* Minimum size to reduce heap buffer to */


/******************/
/* Local Typedefs */
/******************/


/********************/
/* Package Typedefs */
/********************/


/********************/
/* Local Prototypes */
/********************/

static H5HL_free_t *H5HL_remove_free(H5HL_t *heap, H5HL_free_t *fl);
static herr_t H5HL_minimize_heap_space(H5F_t *f, hid_t dxpl_id, H5HL_t *heap);


/*********************/
/* Package Variables */
/*********************/

/* Declare a free list to manage the H5HL_free_t struct */
H5FL_DEFINE(H5HL_free_t);

/* Declare a PQ free list to manage the heap chunk information */
H5FL_BLK_DEFINE(lheap_chunk);


/*****************************/
/* Library Private Variables */
/*****************************/


/*******************/
/* Local Variables */
/*******************/



/*-------------------------------------------------------------------------
 * Function:	H5HL_create
 *
 * Purpose:	Creates a new heap data structure on disk and caches it
 *		in memory.  SIZE_HINT is a hint for the initial size of the
 *		data area of the heap.	If size hint is invalid then a
 *		reasonable (but probably not optimal) size will be chosen.
 *		If the heap ever has to grow, then REALLOC_HINT is the
 *		minimum amount by which the heap will grow.
 *
 * Return:	Success:	Non-negative. The file address of new heap is
 *				returned through the ADDR argument.
 *
 *		Failure:	Negative
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Jul 16 1997
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5HL_create(H5F_t *f, hid_t dxpl_id, size_t size_hint, haddr_t *addr_p/*out*/)
{
    H5HL_t	*heap = NULL;           /* Heap created */
    H5HL_prfx_t *prfx = NULL;           /* Heap prefix */
    hsize_t	total_size;		/* Total heap size on disk	*/
    herr_t	ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_NOAPI(H5HL_create, FAIL)

    /* check arguments */
    HDassert(f);
    HDassert(addr_p);

    /* Adjust size hint as necessary */
    if(size_hint && size_hint < H5HL_SIZEOF_FREE(f))
	size_hint = H5HL_SIZEOF_FREE(f);
    size_hint = H5HL_ALIGN(size_hint);

    /* Allocate new heap structure */
    if(NULL == (heap = H5HL_new(H5F_SIZEOF_SIZE(f), H5F_SIZEOF_ADDR(f), H5HL_SIZEOF_HDR(f))))
	HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, FAIL, "can't allocate new heap struct")

    /* Allocate file space */
    total_size = heap->prfx_size + size_hint;
    if(HADDR_UNDEF == (heap->prfx_addr = H5MF_alloc(f, H5FD_MEM_LHEAP, dxpl_id, total_size)))
	HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, FAIL, "unable to allocate file memory")

    /* Initialize info */
    heap->single_cache_obj = TRUE;
    heap->dblk_addr = heap->prfx_addr + (hsize_t)heap->prfx_size;
    heap->dblk_size = size_hint;
    if(size_hint)
        if(NULL == (heap->dblk_image = H5FL_BLK_CALLOC(lheap_chunk, size_hint)))
            HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, FAIL, "memory allocation failed")

    /* free list */
    if(size_hint) {
	if(NULL == (heap->freelist = H5FL_MALLOC(H5HL_free_t)))
	    HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, FAIL, "memory allocation failed")
	heap->freelist->offset = 0;
	heap->freelist->size = size_hint;
	heap->freelist->prev = heap->freelist->next = NULL;
    } /* end if */
    else
	heap->freelist = NULL;

    /* Allocate the heap prefix */
    if(NULL == (prfx = H5HL_prfx_new(heap)))
	HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, FAIL, "memory allocation failed")

    /* Add to cache */
    if(H5AC_set(f, dxpl_id, H5AC_LHEAP_PRFX, heap->prfx_addr, prfx, H5AC__NO_FLAGS_SET) < 0)
	HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, FAIL, "unable to cache local heap prefix")

    /* Set address to return */
    *addr_p = heap->prfx_addr;

done:
    if(ret_value < 0) {
        if(prfx) {
            if(H5HL_prfx_dest(prfx) < 0)
                HDONE_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy local heap prefix")
        } /* end if */
        else {
            if(heap) {
                if(H5F_addr_defined(heap->prfx_addr))
                    if(H5MF_xfree(f, H5FD_MEM_LHEAP, dxpl_id, heap->prfx_addr, total_size) < 0)
                        HDONE_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "can't release heap data?")
                if(H5HL_dest(heap) < 0)
                    HDONE_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy local heap")
            } /* end if */
        } /* end else */
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HL_create() */


/*-------------------------------------------------------------------------
 * Function:	H5HL_dblk_realloc
 *
 * Purpose:	Reallocate data block for heap
 *
 * Return:	Success:	Non-negative
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *		koziol@hdfgroup.org
 *		Oct 12 2008
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5HL_dblk_realloc(H5F_t *f, hid_t dxpl_id, H5HL_t *heap, size_t new_heap_size)
{
    H5HL_dblk_t *dblk;                  /* Local heap data block */
    haddr_t old_addr;                   /* Old location of heap data block */
    haddr_t new_addr;                   /* New location of heap data block */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5HL_dblk_realloc)

    /* check arguments */
    HDassert(heap);
    HDassert(new_heap_size > 0);

    /* Release old space on disk */
    old_addr = heap->dblk_addr;
    H5_CHECK_OVERFLOW(heap->dblk_size, size_t, hsize_t);
    if(H5MF_xfree(f, H5FD_MEM_LHEAP, dxpl_id, old_addr, (hsize_t)heap->dblk_size) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "can't release old heap data?")

    /* Allocate new space on disk */
    H5_CHECK_OVERFLOW(new_heap_size, size_t, hsize_t);
    if(HADDR_UNDEF == (new_addr = H5MF_alloc(f, H5FD_MEM_LHEAP, dxpl_id, (hsize_t)new_heap_size)))
        HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, FAIL, "unable to allocate file space for heap")

    /* Check if heap data block actually moved in the file */
    if(H5F_addr_eq(old_addr, new_addr)) {
        /* Check if heap data block is contiguous w/prefix */
        if(heap->single_cache_obj) {
            /* Sanity check */
            HDassert(H5F_addr_eq(heap->prfx_addr + heap->prfx_size, heap->dblk_addr));
            HDassert(heap->prfx);

            /* Resize the heap prefix in the cache */
            if(H5AC_resize_pinned_entry(heap->prfx, (size_t)(heap->prfx_size + new_heap_size)) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTRESIZE, FAIL, "unable to resize heap in cache")
        } /* end if */
        else {
            /* Sanity check */
            HDassert(H5F_addr_ne(heap->prfx_addr + heap->prfx_size, heap->dblk_addr));
            HDassert(heap->dblk);

            /* Resize the heap data block in the cache */
            if(H5AC_resize_pinned_entry(heap->dblk, (size_t)new_heap_size) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTRESIZE, FAIL, "unable to resize heap in cache")
        } /* end else */
    } /* end if */
    else {
        /* Check if heap data block was contiguous w/prefix previously */
        if(heap->single_cache_obj) {
            /* Create new heap data block */
            if(NULL == (dblk = H5HL_dblk_new(heap)))
                HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, FAIL, "unable to allocate local heap data block")

            /* Resize current heap prefix */
            heap->prfx_size = H5HL_SIZEOF_HDR(f);
            if(H5AC_resize_pinned_entry(heap->prfx, (size_t)heap->prfx_size) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTRESIZE, FAIL, "unable to resize heap prefix in cache")

            /* Insert data block into cache (pinned) */
            if(H5AC_set(f, dxpl_id, H5AC_LHEAP_DBLK, new_addr, dblk, H5AC__PIN_ENTRY_FLAG) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, FAIL, "unable to cache local heap data block")
            dblk = NULL;

            /* Reset 'single cache object' flag */
            heap->single_cache_obj = FALSE;
        } /* end if */
        else {
            /* Resize the heap data block in the cache */
            /* (ignore [unlikely] case where heap data block ends up
             *      contiguous w/heap prefix again.
             */
            if(H5AC_resize_pinned_entry(heap->dblk, (size_t)new_heap_size) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTRESIZE, FAIL, "unable to resize heap data block in cache")

            /* Relocate the heap data block in the cache */
            if(H5AC_rename(f, H5AC_LHEAP_DBLK, old_addr, new_addr) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTRENAME, FAIL, "unable to move heap data block in cache")
        } /* end else */
    } /* end else */

    /* Update heap info*/
    heap->dblk_addr = new_addr;
    heap->dblk_size = new_heap_size;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HL_dblk_realloc() */


/*-------------------------------------------------------------------------
 * Function:    H5HL_minimize_heap_space
 *
 * Purpose:     Go through the heap's freelist and determine if we can
 *              eliminate the free blocks at the tail of the buffer.
 *
 * Return:      Success:        SUCCEED
 *              Failure:        FAIL
 *
 * Programmer:  Bill Wendling
 *              wendling@ncsa.uiuc.edu
 *              Sept. 16, 2003
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5HL_minimize_heap_space(H5F_t *f, hid_t dxpl_id, H5HL_t *heap)
{
    size_t new_heap_size = heap->dblk_size;     /* New size of heap */
    herr_t ret_value = SUCCEED;                 /* Return value */

    FUNC_ENTER_NOAPI(H5HL_minimize_heap_space, FAIL)

    /* check args */
    HDassert(f);
    HDassert(heap);

    /*
     * Check to see if we can reduce the size of the heap in memory by
     * eliminating free blocks at the tail of the buffer before flushing the
     * buffer out.
     */
    if(heap->freelist) {
        H5HL_free_t    *tmp_fl;
        H5HL_free_t    *last_fl = NULL;

        /* Search for a free block at the end of the buffer */
        for(tmp_fl = heap->freelist; tmp_fl; tmp_fl = tmp_fl->next)
            /* Check if the end of this free block is at the end of the buffer */
            if(tmp_fl->offset + tmp_fl->size == heap->dblk_size) {
                last_fl = tmp_fl;
                break;
            } /* end if */

        /*
         * Found free block at the end of the buffer, decide what to do
         * about it
         */
        if(last_fl) {
            /*
             * If the last free block's size is more than half the memory
             * buffer size (and the memory buffer is larger than the
             * minimum size), reduce or eliminate it.
             */
            if(last_fl->size >= (heap->dblk_size / 2) && heap->dblk_size > H5HL_MIN_HEAP) {
                /*
                 * Reduce size of buffer until it's too small or would
                 * eliminate the free block
                 */
                while(new_heap_size > H5HL_MIN_HEAP &&
                        new_heap_size >= (last_fl->offset + H5HL_SIZEOF_FREE(f)))
                    new_heap_size /= 2;

                /*
                 * Check if reducing the memory buffer size would
                 * eliminate the free block
                 */
                if(new_heap_size < (last_fl->offset + H5HL_SIZEOF_FREE(f))) {
                    /* Check if this is the only block on the free list */
                    if(last_fl->prev == NULL && last_fl->next == NULL) {
                        /* Double the new memory size */
                        new_heap_size *= 2;

                        /* Truncate the free block */
                        last_fl->size = H5HL_ALIGN(new_heap_size - last_fl->offset);
                        new_heap_size = last_fl->offset + last_fl->size;
                        HDassert(last_fl->size >= H5HL_SIZEOF_FREE(f));
                    } /* end if */
                    else {
                        /*
                         * Set the size of the memory buffer to the start
                         * of the free list
                         */
                        new_heap_size = last_fl->offset;

                        /* Eliminate the free block from the list */
                        last_fl = H5HL_remove_free(heap, last_fl);
                    } /* end else */
                } /* end if */
                else {
                    /* Truncate the free block */
                    last_fl->size = H5HL_ALIGN(new_heap_size - last_fl->offset);
                    new_heap_size = last_fl->offset + last_fl->size;
                    HDassert(last_fl->size >= H5HL_SIZEOF_FREE(f));
                    HDassert(last_fl->size == H5HL_ALIGN(last_fl->size));
                } /* end else */
            } /* end if */
        } /* end if */
    } /* end if */

    /*
     * If the heap grew smaller than disk storage then move the
     * data segment of the heap to another contiguous block of disk
     * storage.
     */
    if(new_heap_size != heap->dblk_size) {
	HDassert(new_heap_size < heap->dblk_size);

        /* Resize the memory buffer */
        if(NULL == (heap->dblk_image = H5FL_BLK_REALLOC(lheap_chunk, heap->dblk_image, new_heap_size)))
            HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, FAIL, "memory allocation failed")

        /* Reallocate data block in file */
        if(H5HL_dblk_realloc(f, dxpl_id, heap, new_heap_size) < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_CANTRESIZE, FAIL, "reallocating data block failed")
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5HL_minimize_heap_space() */


/*-------------------------------------------------------------------------
 * Function:    H5HL_protect
 *
 * Purpose:     This function is a wrapper for the H5AC_protect call.
 *
 * Return:      Success:    Non-NULL pointer to the local heap prefix.
 *              Failure:    NULL
 *
 * Programmer:  Bill Wendling
 *              wendling@ncsa.uiuc.edu
 *              Sept. 17, 2003
 *
 *-------------------------------------------------------------------------
 */
H5HL_t *
H5HL_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, H5AC_protect_t rw)
{
    H5HL_cache_prfx_ud_t prfx_udata; /* User data for protecting local heap prefix */
    H5HL_prfx_t *prfx = NULL;   /* Local heap prefix */
    H5HL_dblk_t *dblk = NULL;   /* Local heap data block */
    H5HL_t *heap;               /* Heap data structure */
    unsigned prfx_cache_flags = H5AC__NO_FLAGS_SET;         /* Cache flags for unprotecting prefix entry */
    unsigned dblk_cache_flags = H5AC__NO_FLAGS_SET;         /* Cache flags for unprotecting data block entry */
    H5HL_t *ret_value;          /* Return value */

    FUNC_ENTER_NOAPI(H5HL_protect, NULL)

    /* check arguments */
    HDassert(f);
    HDassert(H5F_addr_defined(addr));

    /* Construct the user data for protect callback */
    prfx_udata.sizeof_size = H5F_SIZEOF_SIZE(f);
    prfx_udata.sizeof_addr = H5F_SIZEOF_ADDR(f);
    prfx_udata.prfx_addr = addr;
    prfx_udata.sizeof_prfx = H5HL_SIZEOF_HDR(f);
    prfx_udata.loaded = FALSE;
    prfx_udata.free_block = H5HL_FREE_NULL;

    /* Protect the local heap prefix */
    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, rw)))
        HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to load heap prefix")

    /* Get the pointer to the heap */
    heap = prfx->heap;

    /* Check if the heap is already pinned in memory */
    /* (for re-entrant situation) */
    if(heap->prots == 0) {
        /* Check if heap has separate data block */
        if(heap->single_cache_obj) {
            /* Set the flag for pinning the prefix when unprotecting it */
            prfx_cache_flags |= H5AC__PIN_ENTRY_FLAG;
        } /* end if */
        else {
            H5HL_cache_dblk_ud_t dblk_udata; /* User data for protecting local heap data block */

            /* Construct the user data for protect callback */
            dblk_udata.heap = heap;
            dblk_udata.free_block = prfx_udata.loaded ? prfx_udata.free_block :
                    (heap->freelist ? heap->freelist->offset : H5HL_FREE_NULL);
            dblk_udata.loaded = FALSE;

            /* Protect the local heap data block */
            if(NULL == (dblk = (H5HL_dblk_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_DBLK, heap->dblk_addr, &dblk_udata, rw)))
                HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to load heap data block")

            /* Pin the prefix, if the data block was loaded from file */
            if(dblk_udata.loaded)
                prfx_cache_flags |= H5AC__PIN_ENTRY_FLAG;

            /* Set the flag for pinning the data block when unprotecting it */
            dblk_cache_flags |= H5AC__PIN_ENTRY_FLAG;
        } /* end if */
    } /* end if */

    /* Increment # of times heap is protected */
    heap->prots++;

    /* Set return value */
    ret_value = heap;

done:
    /* Release the prefix from the cache, now pinned */
    if(prfx && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP_PRFX, heap->prfx_addr, prfx, prfx_cache_flags) < 0)
        HDONE_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, NULL, "unable to release local heap prefix")

    /* Release the data block from the cache, now pinned */
    if(dblk && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP_DBLK, heap->dblk_addr, dblk, dblk_cache_flags) < 0)
        HDONE_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, NULL, "unable to release local heap data block")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HL_protect() */


/*-------------------------------------------------------------------------
 * Function:    H5HL_offset_into
 *
 * Purpose:     Called directly after the call to H5HL_protect so that
 *              a pointer to the object in the heap can be got.
 *
 * Return:      Success:    Valid pointer.
 *              Failure:    NULL
 *
 * Programmer:  Bill Wendling
 *              wendling@ncsa.uiuc.edu
 *              Sept. 17, 2003
 *
 *-------------------------------------------------------------------------
 */
void *
H5HL_offset_into(const H5HL_t *heap, size_t offset)
{
    /*
     * We need to have called some other function before this to get a
     * valid heap pointer. So, this can remain "FUNC_ENTER_NOAPI_NOINIT"
     */
    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5HL_offset_into)

    /* Sanity check */
    HDassert(heap);
    HDassert(offset < heap->dblk_size);

    FUNC_LEAVE_NOAPI(heap->dblk_image + offset)
} /* end H5HL_offset_into() */


/*-------------------------------------------------------------------------
 * Function:    H5HL_unprotect
 *
 * Purpose:     Unprotect the data retrieved by the H5HL_protect call.
 *
 * Return:      Success:    SUCCEED
 *              Failure:    FAIL
 *
 * Programmer:  Bill Wendling
 *              wendling@ncsa.uiuc.edu
 *              Sept. 17, 2003
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5HL_unprotect(H5HL_t *heap)
{
    herr_t  ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(H5HL_unprotect, FAIL)

    /* check arguments */
    HDassert(heap);

    /* Decrement # of times heap is protected */
    heap->prots--;

    /* Check for last unprotection of heap */
    if(heap->prots == 0) {
        /* Check for separate heap data block */
        if(heap->single_cache_obj) {
            /* Mark local heap prefix as evictable again */
            if(H5AC_unpin_entry(heap->prfx) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTUNPIN, FAIL, "unable to unpin local heap data block")
        } /* end if */
        else {
            /* Sanity check */
            HDassert(heap->dblk);

            /* Mark local heap data block as evictable again */
            /* (data block still pins prefix) */
            if(H5AC_unpin_entry(heap->dblk) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTUNPIN, FAIL, "unable to unpin local heap data block")
        } /* end else */
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HL_unprotect() */


/*-------------------------------------------------------------------------
 * Function:	H5HL_remove_free
 *
 * Purpose:	Removes free list element FL from the specified heap and
 *		frees it.
 *
 * Return:	NULL
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Jul 17 1997
 *
 *-------------------------------------------------------------------------
 */
static H5HL_free_t *
H5HL_remove_free(H5HL_t *heap, H5HL_free_t *fl)
{
    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5HL_remove_free)

    if(fl->prev)
        fl->prev->next = fl->next;
    if(fl->next)
        fl->next->prev = fl->prev;

    if(!fl->prev)
        heap->freelist = fl->next;

    FUNC_LEAVE_NOAPI((H5HL_free_t *)H5FL_FREE(H5HL_free_t, fl))
} /* end H5HL_remove_free() */


/*-------------------------------------------------------------------------
 * Function:	H5HL_dirty
 *
 * Purpose:	Mark heap as dirty
 *
 * Return:	Success:	Non-negative
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *		koziol@hdfgroup.org
 *		Oct 12 2008
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5HL_dirty(H5HL_t *heap)
{
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5HL_dirty)

    /* check arguments */
    HDassert(heap);
    HDassert(heap->prfx);

    /* Mark heap data block as dirty, if there is one */
    if(!heap->single_cache_obj) {
        /* Sanity check */
        HDassert(heap->dblk);

        if(H5AC_mark_entry_dirty(heap->dblk) < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_CANTMARKDIRTY, FAIL, "unable to mark heap data block as dirty")
    } /* end if */

    /* Mark heap prefix as dirty */
    if(H5AC_mark_entry_dirty(heap->prfx) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTMARKDIRTY, FAIL, "unable to mark heap prefix as dirty")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HL_dirty() */


/*-------------------------------------------------------------------------
 * Function:	H5HL_insert
 *
 * Purpose:	Inserts a new item into the heap.
 *
 * Return:	Success:	Offset of new item within heap.
 *		Failure:	UFAIL
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Jul 17 1997
 *
 *-------------------------------------------------------------------------
 */
size_t
H5HL_insert(H5F_t *f, hid_t dxpl_id, H5HL_t *heap, size_t buf_size, const void *buf)
{
    H5HL_free_t	*fl = NULL, *last_fl = NULL;
    size_t	offset = 0;
    size_t	need_size;
    hbool_t	found;
    size_t	ret_value;      /* Return value */

    FUNC_ENTER_NOAPI(H5HL_insert, UFAIL)

    /* check arguments */
    HDassert(f);
    HDassert(heap);
    HDassert(buf_size > 0);
    HDassert(buf);

    /* Mark heap as dirty in cache */
    /* (A bit early in the process, but it's difficult to determine in the
     *  code below where to mark the heap as dirty, especially in error cases,
     *  so we just accept that an extra flush of the heap info could occur
     *  if an error occurs -QAK)
     */
    if(H5HL_dirty(heap) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTMARKDIRTY, UFAIL, "unable to mark heap as dirty")

    /*
     * In order to keep the free list descriptors aligned on word boundaries,
     * whatever that might mean, we round the size up to the next multiple of
     * a word.
     */
    need_size = H5HL_ALIGN(buf_size);

    /*
     * Look for a free slot large enough for this object and which would
     * leave zero or at least H5G_SIZEOF_FREE bytes left over.
     */
    for(fl = heap->freelist, found = FALSE; fl; fl = fl->next) {
	if(fl->size > need_size &&
                fl->size - need_size >= H5HL_SIZEOF_FREE(f)) {
	    /* a big enough free block was found */
	    offset = fl->offset;
	    fl->offset += need_size;
	    fl->size -= need_size;
	    HDassert(fl->offset == H5HL_ALIGN(fl->offset));
	    HDassert(fl->size == H5HL_ALIGN(fl->size));
	    found = TRUE;
	    break;
	} else if(fl->size == need_size) {
	    /* free block of exact size found */
	    offset = fl->offset;
	    fl = H5HL_remove_free(heap, fl);
	    found = TRUE;
	    break;
	} else if(!last_fl || last_fl->offset < fl->offset) {
	    /* track free space that's closest to end of heap */
	    last_fl = fl;
	}
    } /* end for */

    /*
     * If no free chunk was large enough, then allocate more space and
     * add it to the free list.	 If the heap ends with a free chunk, we
     * can extend that free chunk.  Otherwise we'll have to make another
     * free chunk.  If the heap must expand, we double its size.
     */
    if(found == FALSE) {
        size_t	need_more;      /* How much more space we need */
        size_t	new_dblk_size;  /* Final size of space allocated for heap data block */
        size_t	old_dblk_size;  /* Previous size of space allocated for heap data block */
        htri_t	extended;       /* Whether the local heap's data segment on disk was extended */

        /* At least double the heap's size, making certain there's enough room
         * for the new object */
	need_more = MAX(need_size, heap->dblk_size);

        /* If there is no last free block or it's not at the end of the heap,
         * and the amount of space to allocate is not big enough to include at
         * least the new object and a free-list info, trim down the amount of
         * space requested to just the amount of space needed.  (Generally
         * speaking, this only occurs when the heap is small -QAK)
         */
	if(!(last_fl && last_fl->offset + last_fl->size == heap->dblk_size)
                && (need_more < (need_size + H5HL_SIZEOF_FREE(f))))
            need_more = need_size;

	new_dblk_size = heap->dblk_size + need_more;
	HDassert(heap->dblk_size < new_dblk_size);
        old_dblk_size = heap->dblk_size;
	H5_CHECK_OVERFLOW(heap->dblk_size, size_t, hsize_t);
	H5_CHECK_OVERFLOW(new_dblk_size, size_t, hsize_t);

        /* Extend current heap if possible */
	extended = H5MF_try_extend(f, dxpl_id, H5FD_MEM_LHEAP, heap->dblk_addr, (hsize_t)(heap->dblk_size), (hsize_t)need_more);
        if(extended < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_CANTEXTEND, UFAIL, "error trying to extend heap")

	/* Check if we extended the heap data block in file */
	if(extended == TRUE) {
            /* Check for prefix & data block contiguous */
            if(heap->single_cache_obj) {
                /* Resize prefix+data block */
                if(H5AC_resize_pinned_entry(heap->prfx, (size_t)(heap->prfx_size + new_dblk_size)) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTRESIZE, UFAIL, "unable to resize heap prefix in cache")
            } /* end if */
            else {
                /* Resize 'standalone' data block */
                if(H5AC_resize_pinned_entry(heap->dblk, (size_t)new_dblk_size) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTRESIZE, UFAIL, "unable to resize heap data block in cache")
            } /* end else */

            /* Note new size */
            heap->dblk_size = new_dblk_size;
	} /* end if */
        else { /* ...if we can't, allocate a new chunk & release the old */
            /* Reallocate data block in file */
            if(H5HL_dblk_realloc(f, dxpl_id, heap, new_dblk_size) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTRESIZE, UFAIL, "reallocating data block failed")
	} /* end if */

        /* If the last free list in the heap is at the end of the heap, extend it */
	if(last_fl && last_fl->offset + last_fl->size == old_dblk_size) {
	    /*
	     * Increase the size of the last free block.
	     */
	    offset = last_fl->offset;
	    last_fl->offset += need_size;
	    last_fl->size += need_more - need_size;
	    HDassert(last_fl->offset == H5HL_ALIGN(last_fl->offset));
	    HDassert(last_fl->size == H5HL_ALIGN(last_fl->size));

	    if (last_fl->size < H5HL_SIZEOF_FREE(f)) {
#ifdef H5HL_DEBUG
		if (H5DEBUG(HL) && last_fl->size) {
		    fprintf(H5DEBUG(HL), "H5HL: lost %lu bytes at line %d\n",
			    (unsigned long)(last_fl->size), __LINE__);
		}
#endif
		last_fl = H5HL_remove_free(heap, last_fl);
	    }
	} /* end if */
        else {
	    /*
	     * Create a new free list element large enough that we can
	     * take some space out of it right away.
	     */
	    offset = old_dblk_size;
	    if(need_more - need_size >= H5HL_SIZEOF_FREE(f)) {
		if(NULL == (fl = H5FL_MALLOC(H5HL_free_t)))
		    HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, UFAIL, "memory allocation failed")
		fl->offset = old_dblk_size + need_size;
		fl->size = need_more - need_size;
		HDassert(fl->offset == H5HL_ALIGN(fl->offset));
		HDassert(fl->size == H5HL_ALIGN(fl->size));
		fl->prev = NULL;
		fl->next = heap->freelist;
		if(heap->freelist)
                    heap->freelist->prev = fl;
		heap->freelist = fl;
#ifdef H5HL_DEBUG
	    } else if (H5DEBUG(HL) && need_more > need_size) {
		fprintf(H5DEBUG(HL),
			"H5HL_insert: lost %lu bytes at line %d\n",
			(unsigned long)(need_more - need_size), __LINE__);
#endif
	    }
	} /* end else */

#ifdef H5HL_DEBUG
	if (H5DEBUG(HL)) {
	    fprintf(H5DEBUG(HL),
		    "H5HL: resize mem buf from %lu to %lu bytes\n",
		    (unsigned long)(old_dblk_size),
		    (unsigned long)(old_dblk_size + need_more));
	}
#endif
	if(NULL == (heap->dblk_image = H5FL_BLK_REALLOC(lheap_chunk, heap->dblk_image, heap->dblk_size)))
	    HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, UFAIL, "memory allocation failed")

	/* Clear new section so junk doesn't appear in the file */
        /* (Avoid clearing section which will be overwritten with newly inserted data) */
	HDmemset(heap->dblk_image + offset + buf_size, 0, (new_dblk_size - (offset + buf_size)));
    } /* end if */

    /* Copy the data into the heap */
    HDmemcpy(heap->dblk_image + offset, buf, buf_size);

    /* Set return value */
    ret_value = offset;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5HL_insert() */


/*-------------------------------------------------------------------------
 * Function:	H5HL_remove
 *
 * Purpose:	Removes an object or part of an object from the heap at
 *		address ADDR of file F.	 The object (or part) to remove
 *		begins at byte OFFSET from the beginning of the heap and
 *		continues for SIZE bytes.
 *
 *		Once part of an object is removed, one must not attempt
 *		to access that part.  Removing the beginning of an object
 *		results in the object OFFSET increasing by the amount
 *		truncated.  Removing the end of an object results in
 *		object truncation.  Removing the middle of an object results
 *		in two separate objects, one at the original offset and
 *		one at the first offset past the removed portion.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Jul 16 1997
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5HL_remove(H5F_t *f, hid_t dxpl_id, H5HL_t *heap, size_t offset, size_t size)
{
    H5HL_free_t		*fl = NULL;
    herr_t      	ret_value = SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI(H5HL_remove, FAIL)

    /* check arguments */
    HDassert(f);
    HDassert(heap);
    HDassert(size > 0);
    HDassert(offset == H5HL_ALIGN(offset));

    size = H5HL_ALIGN(size);

    HDassert(offset < heap->dblk_size);
    HDassert(offset + size <= heap->dblk_size);

    /* Mark heap as dirty in cache */
    /* (A bit early in the process, but it's difficult to determine in the
     *  code below where to mark the heap as dirty, especially in error cases,
     *  so we just accept that an extra flush of the heap info could occur
     *  if an error occurs -QAK)
     */
    if(H5HL_dirty(heap) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTMARKDIRTY, FAIL, "unable to mark heap as dirty")

    /*
     * Check if this chunk can be prepended or appended to an already
     * free chunk.  It might also fall between two chunks in such a way
     * that all three chunks can be combined into one.
     */
    fl = heap->freelist;
    while(fl) {
        H5HL_free_t *fl2 = NULL;

	if((offset + size) == fl->offset) {
	    fl->offset = offset;
	    fl->size += size;
	    HDassert(fl->offset == H5HL_ALIGN(fl->offset));
	    HDassert(fl->size == H5HL_ALIGN(fl->size));
	    fl2 = fl->next;
	    while(fl2) {
		if((fl2->offset + fl2->size) == fl->offset) {
		    fl->offset = fl2->offset;
		    fl->size += fl2->size;
		    HDassert(fl->offset == H5HL_ALIGN(fl->offset));
		    HDassert(fl->size == H5HL_ALIGN(fl->size));
		    fl2 = H5HL_remove_free(heap, fl2);
	            if(((fl->offset + fl->size) == heap->dblk_size) &&
                             ((2 * fl->size) > heap->dblk_size)) {
                        if(H5HL_minimize_heap_space(f, dxpl_id, heap) < 0)
	                    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "heap size minimization failed")
                    }
		    HGOTO_DONE(SUCCEED);
		}
		fl2 = fl2->next;
	    }
	    if(((fl->offset + fl->size) == heap->dblk_size) &&
                     ((2 * fl->size) > heap->dblk_size)) {
                if(H5HL_minimize_heap_space(f, dxpl_id, heap) < 0)
	            HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "heap size minimization failed")
            }
	    HGOTO_DONE(SUCCEED);
	} else if(fl->offset + fl->size == offset) {
	    fl->size += size;
	    fl2 = fl->next;
	    HDassert(fl->size == H5HL_ALIGN(fl->size));
	    while(fl2) {
		if(fl->offset + fl->size == fl2->offset) {
		    fl->size += fl2->size;
		    HDassert(fl->size == H5HL_ALIGN(fl->size));
		    fl2 = H5HL_remove_free(heap, fl2);
	            if(((fl->offset + fl->size) == heap->dblk_size) &&
                            ((2 * fl->size) > heap->dblk_size)) {
                        if(H5HL_minimize_heap_space(f, dxpl_id, heap) < 0)
	                    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "heap size minimization failed")
                    } /* end if */
		    HGOTO_DONE(SUCCEED);
		} /* end if */
		fl2 = fl2->next;
	    } /* end while */
	    if(((fl->offset + fl->size) == heap->dblk_size) &&
                    ((2 * fl->size) > heap->dblk_size)) {
                if(H5HL_minimize_heap_space(f, dxpl_id, heap) < 0)
	            HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "heap size minimization failed")
            } /* end if */
	    HGOTO_DONE(SUCCEED);
	} /* end if */
	fl = fl->next;
    } /* end while */

    /*
     * The amount which is being removed must be large enough to
     * hold the free list data.	 If not, the freed chunk is forever
     * lost.
     */
    if(size < H5HL_SIZEOF_FREE(f)) {
#ifdef H5HL_DEBUG
	if(H5DEBUG(HL)) {
	    fprintf(H5DEBUG(HL), "H5HL: lost %lu bytes\n",
		    (unsigned long) size);
	}
#endif
	HGOTO_DONE(SUCCEED);
    } /* end if */

    /*
     * Add an entry to the free list.
     */
    if(NULL == (fl = H5FL_MALLOC(H5HL_free_t)))
	HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, FAIL, "memory allocation failed")
    fl->offset = offset;
    fl->size = size;
    HDassert(fl->offset == H5HL_ALIGN(fl->offset));
    HDassert(fl->size == H5HL_ALIGN(fl->size));
    fl->prev = NULL;
    fl->next = heap->freelist;
    if(heap->freelist)
        heap->freelist->prev = fl;
    heap->freelist = fl;

    if(((fl->offset + fl->size) == heap->dblk_size) &&
            ((2 * fl->size) > heap->dblk_size)) {
        if(H5HL_minimize_heap_space(f, dxpl_id, heap) < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "heap size minimization failed")
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HL_remove() */


/*-------------------------------------------------------------------------
 * Function:	H5HL_delete
 *
 * Purpose:	Deletes a local heap from disk, freeing disk space used.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Mar 22 2003
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5HL_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr)
{
    H5HL_t	*heap;                  /* Local heap to delete */
    H5HL_cache_prfx_ud_t prfx_udata;    /* User data for protecting local heap prefix */
    H5HL_prfx_t *prfx = NULL;           /* Local heap prefix */
    H5HL_dblk_t *dblk = NULL;           /* Local heap data block */
    unsigned    cache_flags = H5AC__NO_FLAGS_SET;       /* Flags for unprotecting heap */
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_NOAPI(H5HL_delete, FAIL)

    /* check arguments */
    HDassert(f);
    HDassert(H5F_addr_defined(addr));

    /* Construct the user data for protect callback */
    prfx_udata.sizeof_size = H5F_SIZEOF_SIZE(f);
    prfx_udata.sizeof_addr = H5F_SIZEOF_ADDR(f);
    prfx_udata.prfx_addr = addr;
    prfx_udata.sizeof_prfx = H5HL_SIZEOF_HDR(f);
    prfx_udata.loaded = FALSE;
    prfx_udata.free_block = H5HL_FREE_NULL;

    /* Protect the local heap prefix */
    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, H5AC_WRITE)))
        HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load heap prefix")

    /* Get the pointer to the heap */
    heap = prfx->heap;

    /* Check if heap has separate data block */
    if(!heap->single_cache_obj) {
        H5HL_cache_dblk_ud_t dblk_udata; /* User data for protecting local heap data block */

        /* Construct the user data for protect callback */
        dblk_udata.heap = heap;
        dblk_udata.free_block = prfx_udata.loaded ? prfx_udata.free_block :
                (heap->freelist ? heap->freelist->offset : H5HL_FREE_NULL);
        dblk_udata.loaded = FALSE;

        /* Protect the local heap data block */
        if(NULL == (dblk = (H5HL_dblk_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_DBLK, heap->dblk_addr, &dblk_udata, H5AC_WRITE)))
            HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load heap data block")

        /* Pin the prefix, if the data block was loaded from file */
        if(dblk_udata.loaded) {
            if(H5AC_pin_protected_entry(prfx) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTPIN, FAIL, "unable to pin local heap prefix")
        } /* end if */
    } /* end if */

    /* Set the flags for releasing the prefix and data block */
    cache_flags |= H5AC__DIRTIED_FLAG | H5AC__DELETED_FLAG | H5AC__FREE_FILE_SPACE_FLAG;

done:
    /* Release the data block from the cache, now deleted */
    if(dblk && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP_DBLK, heap->dblk_addr, dblk, cache_flags) < 0)
        HDONE_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "unable to release local heap data block")

    /* Release the prefix from the cache, now deleted */
    if(prfx && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP_PRFX, heap->prfx_addr, prfx, cache_flags) < 0)
        HDONE_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "unable to release local heap prefix")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HL_delete() */


/*-------------------------------------------------------------------------
 * Function:	H5HL_get_size
 *
 * Purpose:	Retrieves the current size of a heap
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Nov  7 2005
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5HL_get_size(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t *size)
{
    H5HL_cache_prfx_ud_t prfx_udata;      /* User data for protecting local heap prefix */
    H5HL_prfx_t *prfx = NULL;   /* Local heap prefix */
    H5HL_t *heap;               /* Heap data structure */
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_NOAPI(H5HL_get_size, FAIL)

    /* check arguments */
    HDassert(f);
    HDassert(H5F_addr_defined(addr));
    HDassert(size);

    /* Construct the user data for protect callback */
    prfx_udata.sizeof_size = H5F_SIZEOF_SIZE(f);
    prfx_udata.sizeof_addr = H5F_SIZEOF_ADDR(f);
    prfx_udata.prfx_addr = addr;
    prfx_udata.sizeof_prfx = H5HL_SIZEOF_HDR(f);
    prfx_udata.loaded = FALSE;
    prfx_udata.free_block = H5HL_FREE_NULL;

    /* Protect the local heap prefix */
    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, H5AC_READ)))
        HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load heap prefix")

    /* Get the pointer to the heap */
    heap = prfx->heap;

    /* Set the size to return */
    *size = heap->dblk_size;

done:
    if(prfx && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP_PRFX, heap->prfx_addr, prfx, H5AC__NO_FLAGS_SET) < 0)
        HDONE_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "unable to release local heap prefix")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HL_get_size() */


/*-------------------------------------------------------------------------
 * Function:    H5HL_heapsize
 *
 * Purpose:     Compute the size in bytes of the specified instance of
 *              H5HL_t via H5HL_size()
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Vailin Choi
 *              June 19 2007
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5HL_heapsize(H5F_t *f, hid_t dxpl_id, haddr_t addr, hsize_t *heap_size)
{
    H5HL_cache_prfx_ud_t prfx_udata;      /* User data for protecting local heap prefix */
    H5HL_prfx_t *prfx = NULL;   /* Local heap prefix */
    H5HL_t *heap;               /* Heap data structure */
    herr_t ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_NOAPI(H5HL_heapsize, FAIL)

    /* check arguments */
    HDassert(f);
    HDassert(H5F_addr_defined(addr));
    HDassert(heap_size);

    /* Construct the user data for protect callback */
    prfx_udata.sizeof_size = H5F_SIZEOF_SIZE(f);
    prfx_udata.sizeof_addr = H5F_SIZEOF_ADDR(f);
    prfx_udata.prfx_addr = addr;
    prfx_udata.sizeof_prfx = H5HL_SIZEOF_HDR(f);
    prfx_udata.loaded = FALSE;
    prfx_udata.free_block = H5HL_FREE_NULL;

    /* Protect the local heap prefix */
    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, H5AC_READ)))
        HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load heap prefix")

    /* Get the pointer to the heap */
    heap = prfx->heap;

    /* Accumulate the size of the local heap */
    *heap_size += (hsize_t)(heap->prfx_size + heap->dblk_size);

done:
    if(prfx && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP_PRFX, heap->prfx_addr, prfx, H5AC__NO_FLAGS_SET) < 0)
        HDONE_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "unable to release local heap prefix")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HL_heapsize() */