summaryrefslogtreecommitdiffstats
path: root/src/H5FDcore.c
blob: f15120d637deb4fdcc2f2abfae5c90602e15c7db (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
/*
 * Copyright © 1999-2001 NCSA
 *                       All rights reserved.
 *
 * 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.
 */
#include "H5private.h"		/*library functions			*/
#include "H5Eprivate.h"		/*error handling			*/
#include "H5Fprivate.h"		/*files					*/
#include "H5FDprivate.h"	/*file driver				  */
#include "H5FDcore.h"           /* Core file driver */
#include "H5Iprivate.h"		/*object IDs				  */
#include "H5MMprivate.h"        /* Memory allocation */
#include "H5Pprivate.h"		/*property lists			*/

#undef MAX
#define MAX(X,Y)	((X)>(Y)?(X):(Y))

#undef MIN
#define MIN(X,Y)	((X)<(Y)?(X):(Y))

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

/*
 * 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	*/
    int		fd;			/*backing store file descriptor	*/
    hbool_t	dirty;			/*changes not saved?		*/
} 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)
#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 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_flush(H5FD_t *_file, unsigned closing);
static herr_t H5FD_core_close(H5FD_t *_file);
static int H5FD_core_cmp(const H5FD_t *_f1, const H5FD_t *_f2);
static haddr_t H5FD_core_get_eoa(H5FD_t *_file);
static herr_t H5FD_core_set_eoa(H5FD_t *_file, haddr_t addr);
static haddr_t H5FD_core_get_eof(H5FD_t *_file);
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 const H5FD_class_t H5FD_core_g = {
    "core",					/*name			*/
    MAXADDR,					/*maxaddr		*/
    H5F_CLOSE_WEAK,				/*fc_degree		*/
    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			*/
    NULL,				        /*query			*/
    NULL,					/*alloc			*/
    NULL,					/*free			*/
    H5FD_core_get_eoa,				/*get_eoa		*/
    H5FD_core_set_eoa, 				/*set_eoa		*/
    H5FD_core_get_eof,				/*get_eof		*/
    H5FD_core_read,				/*read			*/
    H5FD_core_write,				/*write			*/
    H5FD_core_flush,				/*flush			*/
    H5FD_FLMAP_SINGLE,				/*fl_map		*/
};

/* Interface initialization */
#define PABLO_MASK	H5FD_core_mask
#define INTERFACE_INIT	H5FD_core_init
static int interface_initialize_g = 0;


/*-------------------------------------------------------------------------
 * 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
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5FD_core_init(void)
{
    hid_t ret_value=H5FD_CORE_g;   /* Return value */

    FUNC_ENTER_NOAPI(H5FD_core_init, FAIL);

    if (H5I_VFL!=H5Iget_type(H5FD_CORE_g))
        H5FD_CORE_g = H5FDregister(&H5FD_core_g);

    /* Set return value */
    ret_value=H5FD_CORE_g;

done:
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * 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
 *
 * Modifications:
 * 		Robb Matzke, 1999-10-19
 *		Added the BACKING_STORE argument. If set then the entire file
 *		contents are flushed to a file with the same name as this
 *		core file.
 *
 *		Raymond Lu, 2001-10-25
 *		Changed the file access list to the new generic list.
 *
 *-------------------------------------------------------------------------
 */
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(H5FD_set_fapl_core, 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(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
 *
 * Modifications:
 *		Robb Matzke, 1999-10-19
 *		Added the BACKING_STORE argument.
 *		
 *		Raymond Lu
 *		2001-10-25
 *		Changed file access list to the new generic property list.
 *
 *-------------------------------------------------------------------------
 */
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(H5Pget_fapl_core, 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=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(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
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static void *
H5FD_core_fapl_get(H5FD_t *_file)
{
    H5FD_core_t		*file = (H5FD_core_t*)_file;
    H5FD_core_fapl_t	*fa = NULL;
    void      *ret_value;       /* Return value */

    FUNC_ENTER_NOAPI(H5FD_core_fapl_get, NULL);

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

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

    /* Set return value */
    ret_value=fa;

done:
    FUNC_LEAVE(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
 *
 * Modifications:
 *		Robb Matzke, 1999-10-19
 *		The backing store file is created and opened if specified.
 *-------------------------------------------------------------------------
 */
static H5FD_t *
H5FD_core_open(const char *name, unsigned UNUSED flags, hid_t fapl_id,
	       haddr_t maxaddr)
{
    H5FD_core_t		*file=NULL;
    H5FD_core_fapl_t	*fa=NULL;
    H5P_genplist_t *plist;      /* Property list pointer */
    int			fd=-1;
    H5FD_t		*ret_value;

    FUNC_ENTER_NOAPI(H5FD_core_open, NULL);
    
    /* Check arguments */
    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");
    if (H5P_DEFAULT!=fapl_id) {
        if(NULL == (plist = H5I_object(fapl_id)))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a file access property list");
        fa = H5P_get_driver_info(plist);
    } /* end if */

    /* Open backing store */
    if (fa && fa->backing_store && name &&
            (fd=HDopen(name, O_CREAT|O_TRUNC|O_RDWR, 0666))<0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open backing store");

    /* Create the new file struct */
    if (NULL==(file=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 = HDstrdup(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 && fa->increment>0) ?  fa->increment : H5FD_CORE_INCREMENT;

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

done:
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * 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
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_core_flush(H5FD_t *_file, unsigned UNUSED closing)
{
    H5FD_core_t	*file = (H5FD_core_t*)_file;
    herr_t      ret_value=SUCCEED;       /* Return value */
    
    FUNC_ENTER_NOAPI(H5FD_core_flush, FAIL);

    /* Write to backing store */
    if (file->dirty && file->fd>=0) {
        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) {
            ssize_t n;

            H5_CHECK_OVERFLOW(size,hsize_t,size_t);
            n = HDwrite(file->fd, ptr, (size_t)size);
            if (n<0 && EINTR==errno)
                continue;
            if (n<0)
                HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "error writing backing store");
            ptr += (size_t)n;
            size -= (size_t)n;
        }
        file->dirty = FALSE;
    }

done:
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5FD_core_close
 *
 * Purpose:	Closes the file.
 *
 * Return:	Success:	0
 *
 *		Failure:	-1
 *
 * Programmer:	Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 * 		Robb Matzke, 1999-10-19
 *		The contents of memory are written to the backing store if
 *		one is open.
 *-------------------------------------------------------------------------
 */
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(H5FD_core_close, FAIL);

    /* Flush */
    if (H5FD_core_flush(_file,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)
        H5MM_xfree(file->mem);
    HDmemset(file, 0, sizeof(H5FD_core_t));
    H5MM_xfree(file);

done:
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * 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
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
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;

    FUNC_ENTER_NOAPI(H5FD_core_cmp, FAIL);

    if (NULL==f1->name && NULL==f2->name) {
        if (f1<f2)
            HGOTO_DONE(-1);
        if (f1>f2)
            HGOTO_DONE(1);
        HGOTO_DONE(0);
    }
    
    if (NULL==f1->name)
        HGOTO_DONE(-1);
    if (NULL==f2->name)
        HGOTO_DONE(1);

    ret_value = HDstrcmp(f1->name, f2->name);

done:
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * 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
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_core_get_eoa(H5FD_t *_file)
{
    haddr_t ret_value;   /* Return value */

    H5FD_core_t	*file = (H5FD_core_t*)_file;
    
    FUNC_ENTER_NOAPI(H5FD_core_get_eoa, HADDR_UNDEF);

    /* Set return value */
    ret_value=file->eoa;

done:
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * 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
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_core_set_eoa(H5FD_t *_file, haddr_t addr)
{
    H5FD_core_t	*file = (H5FD_core_t*)_file;
    herr_t      ret_value=SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI(H5FD_core_set_eoa, FAIL);

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

    file->eoa = addr;

done:
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * 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
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_core_get_eof(H5FD_t *_file)
{
    haddr_t ret_value;   /* Return value */

    H5FD_core_t	*file = (H5FD_core_t*)_file;

    FUNC_ENTER_NOAPI(H5FD_core_get_eof, HADDR_UNDEF);

    /* Set return value */
    ret_value=MAX(file->eof, file->eoa);

done:
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * 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
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
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(H5FD_core_read, FAIL);

    assert(file && file->pub.cls);
    assert(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 (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(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
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
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(H5FD_core_write, FAIL);

    assert(file && file->pub.cls);
    assert(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;

        H5_ASSIGN_OVERFLOW(new_eof,file->increment*((addr+size)/file->increment),hsize_t,size_t);

        if ((addr+size) % file->increment)
            new_eof += file->increment;
        if (NULL==file->mem)
            x = H5MM_malloc(new_eof);
        else
            x = H5MM_realloc(file->mem, new_eof);
        if (!x)
            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate memory block");
        file->mem = x;
        file->eof = new_eof;
    }

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

done:
    FUNC_LEAVE(ret_value);
}