summaryrefslogtreecommitdiffstats
path: root/src/H5FDcore.c
blob: decdbf025f088479b16234a755e30ecaa267d6f4 (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
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Programmer:  Robb Matzke <matzke@llnl.gov>
 *              Tuesday, August 10, 1999
 *
 * Purpose:	A driver which stores the HDF5 data in main memory  using
 *		only the HDF5 public API. This driver is useful for fast
 *		access to small, temporary hdf5 files.
 */

/* Interface initialization */
#define H5_INTERFACE_INIT_FUNC	H5FD_core_init_interface


#include "H5private.h"		/* Generic Functions			*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Fprivate.h"		/* File access				*/
#include "H5FDprivate.h"	/* File drivers				*/
#include "H5FDcore.h"           /* Core file driver			*/
#include "H5Iprivate.h"		/* IDs			  		*/
#include "H5MMprivate.h"	/* Memory management			*/
#include "H5Pprivate.h"		/* Property lists			*/

/* The driver identification number, initialized at runtime */
static hid_t H5FD_CORE_g = 0;

/* Since Windows doesn't follow the rest of the world when it comes
 * to POSIX I/O types, some typedefs and constants are needed to avoid
 * making the code messy with #ifdefs.
 * NOTE: These are only used when writing data to the backing store on
 * file close.
 */
#ifdef H5_HAVE_WIN32_API
typedef unsigned int    h5_core_io_t;
typedef int             h5_core_io_ret_t;
static int H5_CORE_MAX_IO_BYTES_g = INT_MAX;
#else
/* Unix, everyone else */
typedef size_t          h5_core_io_t;
typedef ssize_t         h5_core_io_ret_t;
static size_t H5_CORE_MAX_IO_BYTES_g = SSIZET_MAX;
#endif /* H5_HAVE_WIN32_API */

/* The description of a file belonging to this driver. The `eoa' and `eof'
 * determine the amount of hdf5 address space in use and the high-water mark
 * of the file (the current size of the underlying memory).
 */
typedef struct H5FD_core_t {
    H5FD_t	pub;			/*public stuff, must be first	*/
    char	*name;			/*for equivalence testing	*/
    unsigned char *mem;			/*the underlying memory		*/
    haddr_t	eoa;			/*end of allocated region	*/
    haddr_t	eof;			/*current allocated size	*/
    size_t	increment;		/*multiples for mem allocation	*/
    hbool_t	backing_store;		/*write to file name on flush	*/
    int		fd;			/*backing store file descriptor	*/
    /* Information for determining uniqueness of a file with a backing store */
#ifndef H5_HAVE_WIN32_API
    /* On most systems the combination of device and i-node number uniquely
     * identify a file.
     */
    dev_t       device;                 /*file device number            */
#ifdef H5_VMS
    ino_t       inode[3];               /*file i-node number            */
#else
    ino_t       inode;                  /*file i-node number            */
#endif /*H5_VMS*/
#else
    /* Files in windows are uniquely identified by the volume serial
     * number and the file index (both low and high parts).
     *
     * There are caveats where these numbers can change, especially
     * on FAT file systems.  On NTFS, however, a file should keep
     * those numbers the same until renamed or deleted (though you
     * can use ReplaceFile() on NTFS to keep the numbers the same
     * while renaming).
     *
     * See the MSDN "BY_HANDLE_FILE_INFORMATION Structure" entry for
     * more information.
     *
     * http://msdn.microsoft.com/en-us/library/aa363788(v=VS.85).aspx
     */
    DWORD           nFileIndexLow;
    DWORD           nFileIndexHigh;
    DWORD           dwVolumeSerialNumber;
    
    HANDLE          hFile;      /* Native windows file handle */
#endif /* H5_HAVE_WIN32_API */
    hbool_t	dirty;			/*changes not saved?		*/
    H5FD_file_image_callbacks_t fi_callbacks; /* file image callbacks */

    /* Information from file open flags, for SWMR access */
    hbool_t     swmr_read;      /* Whether the file is open for SWMR read access */
} H5FD_core_t;

/* Driver-specific file access properties */
typedef struct H5FD_core_fapl_t {
    size_t	increment;		/*how much to grow memory	*/
    hbool_t	backing_store;		/*write to file name on flush	*/
} H5FD_core_fapl_t;

/* Allocate memory in multiples of this size by default */
#define H5FD_CORE_INCREMENT		8192

/* These macros check for overflow of various quantities.  These macros
 * assume that file_offset_t is signed and haddr_t and size_t are unsigned.
 *
 * ADDR_OVERFLOW:	Checks whether a file address of type `haddr_t'
 *			is too large to be represented by the second argument
 *			of the file seek function.
 *
 * SIZE_OVERFLOW:	Checks whether a buffer size of type `hsize_t' is too
 *			large to be represented by the `size_t' type.
 *
 * REGION_OVERFLOW:	Checks whether an address and size pair describe data
 *			which can be addressed entirely in memory.
 */
#define MAXADDR 		((haddr_t)((~(size_t)0)-1))
#define ADDR_OVERFLOW(A)	(HADDR_UNDEF==(A) || (A) > (haddr_t)MAXADDR)
#define SIZE_OVERFLOW(Z)	((Z) > (hsize_t)MAXADDR)
#define REGION_OVERFLOW(A,Z)	(ADDR_OVERFLOW(A) || SIZE_OVERFLOW(Z) ||      \
                                 HADDR_UNDEF==(A)+(Z) ||		      \
				 (size_t)((A)+(Z))<(size_t)(A))

/* Prototypes */
static herr_t H5FD_core_term(void);
static void *H5FD_core_fapl_get(H5FD_t *_file);
static H5FD_t *H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
			      haddr_t maxaddr);
static herr_t H5FD_core_close(H5FD_t *_file);
static int H5FD_core_cmp(const H5FD_t *_f1, const H5FD_t *_f2);
static herr_t H5FD_core_query(const H5FD_t *_f1, unsigned long *flags);
static haddr_t H5FD_core_get_eoa(const H5FD_t *_file, H5FD_mem_t type);
static herr_t H5FD_core_set_eoa(H5FD_t *_file, H5FD_mem_t type, haddr_t addr);
static haddr_t H5FD_core_get_eof(const H5FD_t *_file);
static herr_t  H5FD_core_get_handle(H5FD_t *_file, hid_t fapl, void** file_handle);
static herr_t H5FD_core_read(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
			     size_t size, void *buf);
static herr_t H5FD_core_write(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
			      size_t size, const void *buf);
static herr_t H5FD_core_flush(H5FD_t *_file, hid_t dxpl_id, unsigned closing);
static herr_t H5FD_core_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing);

static const H5FD_class_t H5FD_core_g = {
    "core",					/*name			*/
    MAXADDR,					/*maxaddr		*/
    H5F_CLOSE_WEAK,				/*fc_degree		*/
    H5FD_core_term,                             /*terminate             */
    NULL,					/*sb_size		*/
    NULL,					/*sb_encode		*/
    NULL,					/*sb_decode		*/
    sizeof(H5FD_core_fapl_t),			/*fapl_size		*/
    H5FD_core_fapl_get,				/*fapl_get		*/
    NULL,					/*fapl_copy		*/
    NULL, 					/*fapl_free		*/
    0,						/*dxpl_size		*/
    NULL,					/*dxpl_copy		*/
    NULL,					/*dxpl_free		*/
    H5FD_core_open,				/*open			*/
    H5FD_core_close,				/*close			*/
    H5FD_core_cmp,				/*cmp			*/
    H5FD_core_query,			        /*query			*/
    NULL,					/*get_type_map		*/
    NULL,					/*alloc			*/
    NULL,					/*free			*/
    H5FD_core_get_eoa,				/*get_eoa		*/
    H5FD_core_set_eoa, 				/*set_eoa		*/
    H5FD_core_get_eof,				/*get_eof		*/
    H5FD_core_get_handle,                       /*get_handle            */
    H5FD_core_read,				/*read			*/
    H5FD_core_write,				/*write			*/
    H5FD_core_flush,				/*flush			*/
    H5FD_core_truncate,				/*truncate		*/
    NULL,                                       /*lock                  */
    NULL,                                       /*unlock                */
    H5FD_FLMAP_DICHOTOMY			/*fl_map		*/
};


/*--------------------------------------------------------------------------
NAME
   H5FD_core_init_interface -- Initialize interface-specific information
USAGE
    herr_t H5FD_core_init_interface()

RETURNS
    Non-negative on success/Negative on failure
DESCRIPTION
    Initializes any interface-specific data or routines.  (Just calls
    H5FD_core_init currently).

--------------------------------------------------------------------------*/
static herr_t
H5FD_core_init_interface(void)
{
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    FUNC_LEAVE_NOAPI(H5FD_core_init())
} /* H5FD_core_init_interface() */


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_init
 *
 * Purpose:	Initialize this driver by registering the driver with the
 *		library.
 *
 * Return:	Success:	The driver ID for the core driver.
 *
 *		Failure:	Negative.
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5FD_core_init(void)
{
    hid_t ret_value=H5FD_CORE_g;   /* Return value */

    FUNC_ENTER_NOAPI(FAIL)

    if (H5I_VFL!=H5Iget_type(H5FD_CORE_g))
        H5FD_CORE_g = H5FD_register(&H5FD_core_g,sizeof(H5FD_class_t),FALSE);

    /* Set return value */
    ret_value=H5FD_CORE_g;

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*---------------------------------------------------------------------------
 * Function:	H5FD_core_term
 *
 * Purpose:	Shut down the VFD
 *
 * Returns:     Non-negative on success or negative on failure
 *
 * Programmer:  Quincey Koziol
 *              Friday, Jan 30, 2004
 *
 *---------------------------------------------------------------------------
 */
static herr_t
H5FD_core_term(void)
{
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    /* Reset VFL ID */
    H5FD_CORE_g=0;

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5FD_core_term() */


/*-------------------------------------------------------------------------
 * Function:	H5Pset_fapl_core
 *
 * Purpose:	Modify the file access property list to use the H5FD_CORE
 *		driver defined in this source file.  The INCREMENT specifies
 *		how much to grow the memory each time we need more.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		Thursday, February 19, 1998
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pset_fapl_core(hid_t fapl_id, size_t increment, hbool_t backing_store)
{
    H5FD_core_fapl_t	fa;
    H5P_genplist_t *plist;      /* Property list pointer */
    herr_t ret_value;

    FUNC_ENTER_API(FAIL)
    H5TRACE3("e", "izb", fapl_id, increment, backing_store);

    /* Check argument */
    if(NULL == (plist = H5P_object_verify(fapl_id,H5P_FILE_ACCESS)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file access property list")

    fa.increment = increment;
    fa.backing_store = backing_store;

    ret_value= H5P_set_driver(plist, H5FD_CORE, &fa);

done:
    FUNC_LEAVE_API(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:	H5Pget_fapl_core
 *
 * Purpose:	Queries properties set by the H5Pset_fapl_core() function.
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Robb Matzke
 *              Tuesday, August 10, 1999
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pget_fapl_core(hid_t fapl_id, size_t *increment/*out*/,
		 hbool_t *backing_store/*out*/)
{
    H5FD_core_fapl_t	*fa;
    H5P_genplist_t *plist;      /* Property list pointer */
    herr_t      ret_value=SUCCEED;       /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE3("e", "ixx", fapl_id, increment, backing_store);

    if(NULL == (plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file access property list")
    if(H5FD_CORE != H5P_get_driver(plist))
        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "incorrect VFL driver")
    if(NULL == (fa = (H5FD_core_fapl_t *)H5P_get_driver_info(plist)))
        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "bad VFL driver info")

    if (increment)
        *increment = fa->increment;
    if (backing_store)
        *backing_store = fa->backing_store;

done:
    FUNC_LEAVE_API(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_fapl_get
 *
 * Purpose:	Returns a copy of the file access properties.
 *
 * Return:	Success:	Ptr to new file access properties.
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *              Friday, August 13, 1999
 *
 *-------------------------------------------------------------------------
 */
static void *
H5FD_core_fapl_get(H5FD_t *_file)
{
    H5FD_core_t		*file = (H5FD_core_t*)_file;
    H5FD_core_fapl_t	*fa;
    void      *ret_value;       /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    if(NULL == (fa = (H5FD_core_fapl_t *)H5MM_calloc(sizeof(H5FD_core_fapl_t))))
        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")

    fa->increment = file->increment;
    fa->backing_store = (hbool_t)(file->fd >= 0);

    /* Set return value */
    ret_value=fa;

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_open
 *
 * Purpose:	Create memory as an HDF5 file.
 *
 * Return:	Success:	A pointer to a new file data structure. The
 *				public fields will be initialized by the
 *				caller, which is always H5FD_open().
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static H5FD_t *
H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
	       haddr_t maxaddr)
{
    int			o_flags;
    H5FD_core_t		*file=NULL;
    H5FD_core_fapl_t	*fa=NULL;
    H5P_genplist_t *plist;      /* Property list pointer */
#ifdef H5_HAVE_WIN32_API
    struct _BY_HANDLE_FILE_INFORMATION fileinfo;
#endif
    h5_stat_t		sb;
    int			fd=-1;
    H5FD_file_image_info_t   file_image_info;
    H5FD_t		*ret_value;

    FUNC_ENTER_NOAPI_NOINIT

    /* Check arguments */
    if(!name || !*name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "invalid file name")
    if(0 == maxaddr || HADDR_UNDEF == maxaddr)
        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, NULL, "bogus maxaddr")
    if(ADDR_OVERFLOW(maxaddr))
        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, NULL, "maxaddr overflow")
    HDassert(H5P_DEFAULT != fapl_id);
    if(NULL == (plist = (H5P_genplist_t *)H5I_object(fapl_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a file access property list")
    if(NULL == (fa = (H5FD_core_fapl_t *)H5P_get_driver_info(plist)))
        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, NULL, "bad VFL driver info")

    /* Build the open flags */
    o_flags = (H5F_ACC_RDWR & flags) ? O_RDWR : O_RDONLY;
    if(H5F_ACC_TRUNC & flags) o_flags |= O_TRUNC;
    if(H5F_ACC_CREAT & flags) o_flags |= O_CREAT;
    if(H5F_ACC_EXCL & flags) o_flags |= O_EXCL;

    /* Retrieve initial file image info */
    if(H5P_get(plist, H5F_ACS_FILE_IMAGE_INFO_NAME, &file_image_info) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get initial file image info")

    /* If the file image exists and this is an open, make sure the file doesn't exist */
    HDassert(((file_image_info.buffer != NULL) && (file_image_info.size > 0)) ||
             ((file_image_info.buffer == NULL) && (file_image_info.size == 0)));
    HDmemset(&sb, 0, sizeof(sb));
    if((file_image_info.buffer != NULL) && !(H5F_ACC_CREAT & flags)) {
        if(HDopen(name, o_flags, 0666) >= 0)
            HGOTO_ERROR(H5E_FILE, H5E_FILEEXISTS, NULL, "file already exists")
        
        /* If backing store is requested, create and stat the file
         * Note: We are forcing the O_CREAT flag here, even though this is 
         * technically an open.
         */
        if(fa->backing_store) {
            if((fd = HDopen(name, o_flags | O_CREAT, 0666)) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to create file")
            if(HDfstat(fd, &sb) < 0)
                HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, NULL, "unable to fstat file")
        } /* end if */
    }  /* end if */
    /* Open backing store, and get stat() from file.  The only case that backing
     * store is off is when  the backing_store flag is off and H5F_ACC_CREAT is
     * on. */
    else if(fa->backing_store || !(H5F_ACC_CREAT & flags)) {
        if((fd = HDopen(name, o_flags, 0666)) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open file")
        if(HDfstat(fd, &sb) < 0)
            HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, NULL, "unable to fstat file")
    } /* end if */

    /* Create the new file struct */
    if(NULL == (file = (H5FD_core_t *)H5MM_calloc(sizeof(H5FD_core_t))))
        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "unable to allocate file struct")
    file->fd = fd;
    if(name && *name)
        file->name = H5MM_xstrdup(name);

    /* The increment comes from either the file access property list or the
     * default value. But if the file access property list was zero then use
     * the default value instead.
     */
    file->increment = (fa->increment>0) ?  fa->increment : H5FD_CORE_INCREMENT;

    /* If save data in backing store. */
    file->backing_store = fa->backing_store;

    /* Save file image callbacks */
    file->fi_callbacks = file_image_info.callbacks;

    if(fd >= 0) {
        /* Retrieve information for determining uniqueness of file */
#ifdef H5_HAVE_WIN32_API
        file->hFile = (HANDLE)_get_osfhandle(fd);
        if(INVALID_HANDLE_VALUE == file->hFile)
            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to get Windows file handle")

        if(!GetFileInformationByHandle((HANDLE)file->hFile, &fileinfo))
            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to get Windows file information")

        file->nFileIndexHigh = fileinfo.nFileIndexHigh;
        file->nFileIndexLow = fileinfo.nFileIndexLow;
        file->dwVolumeSerialNumber = fileinfo.dwVolumeSerialNumber;
#else /* H5_HAVE_WIN32_API */
        file->device = sb.st_dev;
#ifdef H5_VMS
        file->inode[0] = sb.st_ino[0];
        file->inode[1] = sb.st_ino[1];
        file->inode[2] = sb.st_ino[2];
#else
        file->inode = sb.st_ino;
#endif /* H5_VMS */

#endif /* H5_HAVE_WIN32_API */
    } /* end if */

    /* If an existing file is opened, load the whole file into memory. */
    if(!(H5F_ACC_CREAT & flags)) {
        size_t size;

        /* Retrieve file size */
        if(file_image_info.buffer && file_image_info.size > 0)
            size = file_image_info.size;
        else
            size = (size_t)sb.st_size;

        /* Check if we should allocate the memory buffer and read in existing data */
        if(size) {
            /* Allocate memory for the file's data, using the file image callback if available. */
            if(file->fi_callbacks.image_malloc) {
                if(NULL == (file->mem = (unsigned char*)file->fi_callbacks.image_malloc(size, H5FD_FILE_IMAGE_OP_FILE_OPEN, file->fi_callbacks.udata)))
                    HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "image malloc callback failed")
            } /* end if */
            else {
                if(NULL == (file->mem = (unsigned char*)H5MM_malloc(size)))
                    HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "unable to allocate memory block")
            } /* end else */

            /* Set up data structures */
            file->eof = size;

            /* If there is an initial file image, copy it, using the callback if possible */
            if(file_image_info.buffer && file_image_info.size > 0) {
                if(file->fi_callbacks.image_memcpy) {
                    if(file->mem != file->fi_callbacks.image_memcpy(file->mem, file_image_info.buffer, size, H5FD_FILE_IMAGE_OP_FILE_OPEN, file->fi_callbacks.udata))
                        HGOTO_ERROR(H5E_FILE, H5E_CANTCOPY, NULL, "image_memcpy callback failed")
                } /* end if */
                else
                    HDmemcpy(file->mem, file_image_info.buffer, size);
            } /* end if */
            /* Read in existing data from the file if there is no image */
            else {
                /* Read in existing data, being careful of interrupted system calls,
                 * partial results, and the end of the file.
                 */
                while(size > 0) {
                    h5_core_io_t        bytes_in        = 0;    /* # of bytes to read       */
                    h5_core_io_ret_t    bytes_read      = -1;   /* # of bytes actually read */
                    
                    /* Trying to read more bytes than the return type can handle is
                     * undefined behavior in POSIX.
                     */
                    if(size > H5_CORE_MAX_IO_BYTES_g)
                        bytes_in = H5_CORE_MAX_IO_BYTES_g;
                    else
                        bytes_in = (h5_core_io_t)size;
                    
                    do {
                        bytes_read = HDread(file->fd, file->mem, bytes_in);
                    } while(-1 == bytes_read && EINTR == errno);
                    
                    if(-1 == bytes_read) { /* error */
                        int myerrno = errno;
                        time_t mytime = HDtime(NULL);
                        HDoff_t myoffset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);

                        HGOTO_ERROR(H5E_IO, H5E_READERROR, NULL, "file read failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', file->mem = %p, size = %lu, offset = %llu", HDctime(&mytime), file->name, file->fd, myerrno, HDstrerror(myerrno), file->mem, (unsigned long)size, (unsigned long long)myoffset);
                    } /* end if */
                    
                    HDassert(bytes_read >= 0);
                    HDassert((size_t)bytes_read <= size);
                    
                    size -= (size_t)bytes_read;
                } /* end while */
            } /* end else */
        } /* end if */
    } /* end if */

    /* Check for SWMR reader access */
    if(flags & H5F_ACC_SWMR_READ)
        file->swmr_read = TRUE;

    /* Set return value */
    ret_value = (H5FD_t *)file;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_core_open() */


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_close
 *
 * Purpose:	Closes the file.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_core_close(H5FD_t *_file)
{
    H5FD_core_t	*file = (H5FD_core_t*)_file;
    herr_t ret_value = SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Flush any changed buffers */
    if(H5FD_core_flush(_file, (hid_t)-1, TRUE) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTFLUSH, FAIL, "unable to flush file")

    /* Release resources */
    if(file->fd >= 0)
        HDclose(file->fd);
    if(file->name)
        H5MM_xfree(file->name);
    if(file->mem) {
        /* Use image callback if available */
        if(file->fi_callbacks.image_free) {
            if(file->fi_callbacks.image_free(file->mem, H5FD_FILE_IMAGE_OP_FILE_CLOSE, file->fi_callbacks.udata) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "image_free callback failed")
        } /* end if */
        else
            H5MM_xfree(file->mem);
    } /* end if */
    HDmemset(file, 0, sizeof(H5FD_core_t));
    H5MM_xfree(file);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_core_close() */


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_cmp
 *
 * Purpose:	Compares two files belonging to this driver by name. If one
 *		file doesn't have a name then it is less than the other file.
 *		If neither file has a name then the comparison is by file
 *		address.
 *
 * Return:	Success:	A value like strcmp()
 *
 *		Failure:	never fails (arguments were checked by the
 *				caller).
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static int
H5FD_core_cmp(const H5FD_t *_f1, const H5FD_t *_f2)
{
    const H5FD_core_t	*f1 = (const H5FD_core_t*)_f1;
    const H5FD_core_t	*f2 = (const H5FD_core_t*)_f2;
    int			ret_value = 0;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if(f1->fd >= 0 && f2->fd >= 0) {
        /* Compare low level file information for backing store */
#ifdef H5_HAVE_WIN32_API
        if(f1->dwVolumeSerialNumber < f2->dwVolumeSerialNumber) HGOTO_DONE(-1)
        if(f1->dwVolumeSerialNumber > f2->dwVolumeSerialNumber) HGOTO_DONE(1)

        if(f1->nFileIndexHigh < f2->nFileIndexHigh) HGOTO_DONE(-1)
        if(f1->nFileIndexHigh > f2->nFileIndexHigh) HGOTO_DONE(1)

        if(f1->nFileIndexLow < f2->nFileIndexLow) HGOTO_DONE(-1)
        if(f1->nFileIndexLow > f2->nFileIndexLow) HGOTO_DONE(1)

#else
#ifdef H5_DEV_T_IS_SCALAR
        if (f1->device < f2->device) HGOTO_DONE(-1)
        if (f1->device > f2->device) HGOTO_DONE(1)
#else /* H5_DEV_T_IS_SCALAR */
        /* If dev_t isn't a scalar value on this system, just use memcmp to
         * determine if the values are the same or not.  The actual return value
         * shouldn't really matter...
         */
        if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t))<0) HGOTO_DONE(-1)
        if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t))>0) HGOTO_DONE(1)
#endif /* H5_DEV_T_IS_SCALAR */

#ifndef H5_VMS
        if (f1->inode < f2->inode) HGOTO_DONE(-1)
        if (f1->inode > f2->inode) HGOTO_DONE(1)
#else
        if(HDmemcmp(&(f1->inode),&(f2->inode),3*sizeof(ino_t))<0) HGOTO_DONE(-1)
        if(HDmemcmp(&(f1->inode),&(f2->inode),3*sizeof(ino_t))>0) HGOTO_DONE(1)
#endif /* H5_VMS */

#endif /*H5_HAVE_WIN32_API*/
    } /* end if */
    else {
        if (NULL==f1->name && NULL==f2->name) {
            if (f1<f2)
                HGOTO_DONE(-1)
            if (f1>f2)
                HGOTO_DONE(1)
            HGOTO_DONE(0)
        } /* end if */

        if (NULL==f1->name)
            HGOTO_DONE(-1)
        if (NULL==f2->name)
            HGOTO_DONE(1)

        ret_value = HDstrcmp(f1->name, f2->name);
    } /* end else */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_core_cmp() */


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_query
 *
 * Purpose:	Set the flags that this VFL driver is capable of supporting.
 *              (listed in H5FDpublic.h)
 *
 * Return:	Success:	non-negative
 *		Failure:	negative
 *
 * Programmer:	Quincey Koziol
 *              Tuesday, October  7, 2008
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_core_query(const H5FD_t * _file, unsigned long *flags /* out */)
{
    const H5FD_core_t	*file = (const H5FD_core_t*)_file;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    /* Set the VFL feature flags that this driver supports */
    if(flags) {
        *flags = 0;
        *flags |= H5FD_FEAT_AGGREGATE_METADATA; /* OK to aggregate metadata allocations */
        *flags |= H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
        *flags |= H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
        *flags |= H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
        *flags |= H5FD_FEAT_ALLOW_FILE_IMAGE;   /* OK to use file image feature with this VFD */
        *flags |= H5FD_FEAT_CAN_USE_FILE_IMAGE_CALLBACKS;       /* OK to use file image callbacks with this VFD */

        /* If the backing store is open, a POSIX file handle is available */
        if(file && file->fd >= 0 && file->backing_store)
            *flags |= H5FD_FEAT_POSIX_COMPAT_HANDLE; /* VFD handle is POSIX I/O call compatible */
    } /* end if */

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5FD_core_query() */


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_get_eoa
 *
 * Purpose:	Gets the end-of-address marker for the file. The EOA marker
 *		is the first address past the last byte allocated in the
 *		format address space.
 *
 * Return:	Success:	The end-of-address marker.
 *
 *		Failure:	HADDR_UNDEF
 *
 * Programmer:	Robb Matzke
 *              Monday, August  2, 1999
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_core_get_eoa(const H5FD_t *_file, H5FD_mem_t UNUSED type)
{
    const H5FD_core_t	*file = (const H5FD_core_t*)_file;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    FUNC_LEAVE_NOAPI(file->eoa)
}


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_set_eoa
 *
 * Purpose:	Set the end-of-address marker for the file. This function is
 *		called shortly after an existing HDF5 file is opened in order
 *		to tell the driver where the end of the HDF5 data is located.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_core_set_eoa(H5FD_t *_file, H5FD_mem_t UNUSED type, haddr_t addr)
{
    H5FD_core_t	*file = (H5FD_core_t*)_file;
    herr_t ret_value = SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    if(ADDR_OVERFLOW(addr))
        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "address overflow")

    file->eoa = addr;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_core_set_eoa() */


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_get_eof
 *
 * Purpose:	Returns the end-of-file marker, which is the greater of
 *		either the size of the underlying memory or the HDF5
 *		end-of-address markers.
 *
 * Return:	Success:	End of file address, the first address past
 *				the end of the "file", either the memory
 *				or the HDF5 file.
 *
 *		Failure:	HADDR_UNDEF
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_core_get_eof(const H5FD_t *_file)
{
    const H5FD_core_t	*file = (const H5FD_core_t*)_file;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    FUNC_LEAVE_NOAPI(MAX(file->eof, file->eoa))
}


/*-------------------------------------------------------------------------
 * Function:       H5FD_core_get_handle
 *
 * Purpose:        Returns the file handle of CORE file driver.
 *
 * Returns:        Non-negative if succeed or negative if fails.
 *
 * Programmer:     Raymond Lu
 *                 Sept. 16, 2002
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_core_get_handle(H5FD_t *_file, hid_t fapl, void** file_handle)
{
    H5FD_core_t *file = (H5FD_core_t *)_file;   /* core VFD info */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Check args */
    if(!file_handle)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "file handle not valid")

    /* Check for non-default FAPL */
    if(H5P_FILE_ACCESS_DEFAULT != fapl && H5P_DEFAULT != fapl) {
        H5P_genplist_t *plist;  /* Property list pointer */

        /* Get the FAPL */
        if(NULL == (plist = (H5P_genplist_t *)H5I_object(fapl)))
            HGOTO_ERROR(H5E_VFL, H5E_BADTYPE, FAIL, "not a file access property list")

        /* Check if private property for retrieving the backing store POSIX
         * file descriptor is set.  (This should not be set except within the
         * library)  QAK - 2009/12/04
         */
        if(H5P_exist_plist(plist, H5F_ACS_WANT_POSIX_FD_NAME) > 0) {
            hbool_t want_posix_fd;  /* Setting for retrieving file descriptor from core VFD */

            /* Get property */
            if(H5P_get(plist, H5F_ACS_WANT_POSIX_FD_NAME, &want_posix_fd) < 0)
                HGOTO_ERROR(H5E_VFL, H5E_CANTGET, FAIL, "can't get property of retrieving file descriptor")

            /* If property is set, pass back the file descriptor instead of the memory address */
            if(want_posix_fd)
                *file_handle = &(file->fd);
            else
                *file_handle = &(file->mem);
        } /* end if */
        else
            *file_handle = &(file->mem);
    } /* end if */
    else
        *file_handle = &(file->mem);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_core_get_handle() */


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_read
 *
 * Purpose:	Reads SIZE bytes of data from FILE beginning at address ADDR
 *		into buffer BUF according to data transfer properties in
 *		DXPL_ID.
 *
 * Return:	Success:	Zero. Result is stored in caller-supplied
 *				buffer BUF.
 *
 *		Failure:	-1, Contents of buffer BUF are undefined.
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5FD_core_read(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, haddr_t addr,
	       size_t size, void *buf/*out*/)
{
    H5FD_core_t	*file = (H5FD_core_t*)_file;
    herr_t      ret_value=SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    HDassert(file && file->pub.cls);
    HDassert(buf);

    /* Check for overflow conditions */
    if (HADDR_UNDEF == addr)
        HGOTO_ERROR(H5E_IO, H5E_OVERFLOW, FAIL, "file address overflowed")
    if (REGION_OVERFLOW(addr, size))
        HGOTO_ERROR(H5E_IO, H5E_OVERFLOW, FAIL, "file address overflowed")
    /* If the file is open for SWMR read access, allow access to data past
     * the end of the allocated space (the 'eoa').  This is done because the
     * eoa stored in the file's superblock might be out of sync with the
     * objects being written within the file by the application performing
     * SWMR write operations.
     */
    if(!file->swmr_read && (addr + size) > file->eoa)
        HGOTO_ERROR(H5E_IO, H5E_OVERFLOW, FAIL, "file address overflowed")

    /* Read the part which is before the EOF marker */
    if (addr < file->eof) {
        size_t nbytes;
#ifndef NDEBUG
        hsize_t temp_nbytes;

        temp_nbytes = file->eof-addr;
        H5_CHECK_OVERFLOW(temp_nbytes,hsize_t,size_t);
        nbytes = MIN(size,(size_t)temp_nbytes);
#else /* NDEBUG */
        nbytes = MIN(size,(size_t)(file->eof-addr));
#endif /* NDEBUG */

        HDmemcpy(buf, file->mem + addr, nbytes);
        size -= nbytes;
        addr += nbytes;
        buf = (char *)buf + nbytes;
    }

    /* Read zeros for the part which is after the EOF markers */
    if (size > 0)
        HDmemset(buf, 0, size);

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_write
 *
 * Purpose:	Writes SIZE bytes of data to FILE beginning at address ADDR
 *		from buffer BUF according to data transfer properties in
 *		DXPL_ID.
 *
 * Return:	Success:	Zero
 *
 *		Failure:	-1
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5FD_core_write(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, haddr_t addr,
		size_t size, const void *buf)
{
    H5FD_core_t *file = (H5FD_core_t*)_file;
    herr_t ret_value = SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    HDassert(file && file->pub.cls);
    HDassert(buf);

    /* Check for overflow conditions */
    if(REGION_OVERFLOW(addr, size))
        HGOTO_ERROR(H5E_IO, H5E_OVERFLOW, FAIL, "file address overflowed")
    if(addr + size > file->eoa)
        HGOTO_ERROR(H5E_IO, H5E_OVERFLOW, FAIL, "file address overflowed")

    /*
     * Allocate more memory if necessary, careful of overflow. Also, if the
     * allocation fails then the file should remain in a usable state.  Be
     * careful of non-Posix realloc() that doesn't understand what to do when
     * the first argument is null.
     */
    if(addr + size > file->eof) {
        unsigned char *x;
        size_t new_eof;

        /* Determine new size of memory buffer */
        H5_ASSIGN_OVERFLOW(new_eof, file->increment * ((addr + size) / file->increment), hsize_t, size_t);
        if((addr + size) % file->increment)
            new_eof += file->increment;

        /* (Re)allocate memory for the file buffer, using callbacks if available */
        if(file->fi_callbacks.image_realloc) {
            if(NULL == (x = (unsigned char *)file->fi_callbacks.image_realloc(file->mem, new_eof, H5FD_FILE_IMAGE_OP_FILE_RESIZE, file->fi_callbacks.udata)))
                HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block of %llu bytes with callback", (unsigned long long)new_eof)
        } /* end if */
        else {
            if(NULL == (x = (unsigned char *)H5MM_realloc(file->mem, new_eof)))
                HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block of %llu bytes", (unsigned long long)new_eof)
        } /* end else */

#ifdef H5_CLEAR_MEMORY
HDmemset(x + file->eof, 0, (size_t)(new_eof - file->eof));
#endif /* H5_CLEAR_MEMORY */
        file->mem = x;

        file->eof = new_eof;
    } /* end if */

    /* Write from BUF to memory */
    HDmemcpy(file->mem + addr, buf, size);

    /* Mark memory buffer as modified */
    file->dirty = TRUE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_core_write() */


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_flush
 *
 * Purpose:	Flushes the file to backing store if there is any and if the
 *		dirty flag is set.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Robb Matzke
 *              Friday, October 15, 1999
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5FD_core_flush(H5FD_t *_file, hid_t UNUSED dxpl_id, unsigned UNUSED closing)
{
    H5FD_core_t	*file = (H5FD_core_t*)_file;
    herr_t      ret_value=SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Write to backing store */
    if (file->dirty && file->fd>=0 && file->backing_store) {
        haddr_t size = file->eof;
        unsigned char *ptr = file->mem;

        if (0!=HDlseek(file->fd, (off_t)0, SEEK_SET))
            HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "error seeking in backing store")
        
        while (size > 0) {

            h5_core_io_t        bytes_in        = 0;    /* # of bytes to write  */
            h5_core_io_ret_t    bytes_wrote     = -1;   /* # of bytes written   */ 

            /* Trying to write more bytes than the return type can handle is
             * undefined behavior in POSIX.
             */
            if(size > H5_CORE_MAX_IO_BYTES_g)
                bytes_in = H5_CORE_MAX_IO_BYTES_g;
            else
                bytes_in = (h5_core_io_t)size;

            do {
                bytes_wrote = HDwrite(file->fd, ptr, bytes_in);
            } while(-1 == bytes_wrote && EINTR == errno);
            
            if(-1 == bytes_wrote) { /* error */
                int myerrno = errno;
                time_t mytime = HDtime(NULL);
                HDoff_t myoffset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);

                HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "write to backing store failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', ptr = %p, size = %lu, offset = %llu", HDctime(&mytime), file->name, file->fd, myerrno, HDstrerror(myerrno), ptr, (unsigned long)size, (unsigned long long)myoffset);
            } /* end if */
            
            HDassert(bytes_wrote > 0);
            HDassert((size_t)bytes_wrote <= size);

            size -= (size_t)bytes_wrote;
            ptr = (unsigned char *)ptr + bytes_wrote;
            
        } /* end while */
        
        file->dirty = FALSE;
    }

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_truncate
 *
 * Purpose:	Makes sure that the true file size is the same (or larger)
 *		than the end-of-address.
 *
 *		Addendum -- 12/2/11
 *		For file images opened with the core file driver, it is 
 *		necessary that we avoid reallocating the core file driver's
 *		buffer uneccessarily.
 *
 *		To this end, I have made the following functional changes
 *		to this function.  
 *
 *		If we are closing, and there is no backing store, this 
 *		function becomes a no-op.
 *
 *		If we are closing, and there is backing store, we set the
 *		eof to equal the eoa, and truncate the backing store to 
 *		the new eof
 *
 *		If we are not closing, we realloc the buffer to size equal 
 *		to the smallest multiple of the allocation increment that 
 *		equals or exceeds the eoa and set the eof accordingly.  
 *		Note that we no longer truncate	the backing store to the 
 *		new eof if applicable.
 *							-- JRM
 *
 * Return:	Success:	Non-negative
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *              Tuesday, October  7, 2008
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5FD_core_truncate(H5FD_t *_file, hid_t UNUSED dxpl_id, hbool_t closing)
{
    H5FD_core_t *file = (H5FD_core_t*)_file;
    size_t new_eof;                             /* New size of memory buffer */
    herr_t ret_value = SUCCEED;                 /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    HDassert(file);

    /* if we are closing and not using backing store, do nothing */
    if(!closing || file->backing_store) {
        if(closing) /* set eof to eoa */
            new_eof = file->eoa;
        else { /* set eof to smallest multiple of increment that exceeds eoa */
            /* Determine new size of memory buffer */
            H5_ASSIGN_OVERFLOW(new_eof, file->increment * (file->eoa / file->increment), hsize_t, size_t);
            if(file->eoa % file->increment)
                new_eof += file->increment;
        } /* end else */

        /* Extend the file to make sure it's large enough */
        if(!H5F_addr_eq(file->eof, (haddr_t)new_eof)) {
            unsigned char *x;       /* Pointer to new buffer for file data */

            /* (Re)allocate memory for the file buffer, using callback if available */
            if(file->fi_callbacks.image_realloc) {
                if(NULL == (x = (unsigned char *)file->fi_callbacks.image_realloc(file->mem, new_eof, H5FD_FILE_IMAGE_OP_FILE_RESIZE, file->fi_callbacks.udata)))
                  HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block with callback")
            } /* end if */
            else {
                if(NULL == (x = (unsigned char *)H5MM_realloc(file->mem, new_eof)))
                    HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block")
            } /* end else */

#ifdef H5_CLEAR_MEMORY
            if(file->eof < new_eof)
                HDmemset(x + file->eof, 0, (size_t)(new_eof - file->eof));
#endif /* H5_CLEAR_MEMORY */
            file->mem = x;

            /* Update backing store, if using it and if closing */
            if(closing && (file->fd >= 0) && file->backing_store) {
#ifdef H5_HAVE_WIN32_API
                LARGE_INTEGER   li;         /* 64-bit (union) integer for SetFilePointer() call */
                DWORD           dwPtrLow;   /* Low-order pointer bits from SetFilePointer()
                                             * Only used as an error code here.
                                             */
                DWORD           dwError;    /* DWORD error code from GetLastError() */
                BOOL            bError;     /* Boolean error flag */

                /* Windows uses this odd QuadPart union for 32/64-bit portability */
                li.QuadPart = (__int64)file->eoa;

                /* Extend the file to make sure it's large enough.
                 *
                 * Since INVALID_SET_FILE_POINTER can technically be a valid return value
                 * from SetFilePointer(), we also need to check GetLastError().
                 */
                dwPtrLow = SetFilePointer(file->hFile, li.LowPart, &li.HighPart, FILE_BEGIN);
                if(INVALID_SET_FILE_POINTER == dwPtrLow) {
                    dwError = GetLastError();
                    if(dwError != NO_ERROR )
                        HGOTO_ERROR(H5E_FILE, H5E_FILEOPEN, FAIL, "unable to set file pointer")
                }

                bError = SetEndOfFile(file->hFile);
                if(0 == bError)
                    HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
#else /* H5_HAVE_WIN32_API */
#ifdef H5_VMS
                /* Reset seek offset to the beginning of the file, so that the file isn't
                 * re-extended later.  This may happen on Open VMS. */
                if(-1 == HDlseek(file->fd, (HDoff_t)0, SEEK_SET))
                    HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
#endif /* H5_VMS */
                if(-1 == HDftruncate(file->fd, (HDoff_t)new_eof))
                    HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
#endif /* H5_HAVE_WIN32_API */
            } /* end if */

            /* Update the eof value */
            file->eof = new_eof;
        } /* end if */
    } /* end if(file->eof < file->eoa) */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_core_truncate() */