summaryrefslogtreecommitdiffstats
path: root/src/H5Dcontig.c
blob: 525d557fd1e127a64d39babf6e7e95db6f28fc39 (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
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
 * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Programmer: 	Quincey Koziol <koziol@ncsa.uiuc.edu>
 *	       	Thursday, September 28, 2000
 *
 * Purpose:
 *      Contiguous dataset I/O functions. These routines are similar to
 *      the H5F_istore_* routines and really only an abstract way of dealing
 *      with the data sieve buffer from H5F_seg_read/write.
 */

#define H5F_PACKAGE		/*suppress error about including H5Fpkg	  */

/* Pablo information */
/* (Put before include files to avoid problems with inline functions) */
#define PABLO_MASK	H5Fcontig_mask

#include "H5private.h"		/* Generic Functions			*/
#include "H5Dprivate.h"		/* Dataset functions			*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Fpkg.h"
#include "H5FDprivate.h"	/*file driver				  */
#include "H5FLprivate.h"	/*Free Lists	  */
#include "H5MFprivate.h"	/*file memory management		*/
#include "H5Oprivate.h"		/* Object headers		  	*/
#include "H5Pprivate.h"		/* Property lists			*/
#include "H5Sprivate.h"		/* Dataspace functions			*/
#include "H5Vprivate.h"		/* Vector and array functions		*/

/* MPIO, MPIPOSIX, & FPHDF5 drivers needed for special checks */
#include "H5FDfphdf5.h"
#include "H5FDmpio.h"
#include "H5FDmpiposix.h"

/* Private prototypes */
static herr_t
H5F_contig_write(H5F_t *f, hsize_t max_data, haddr_t addr,
    const size_t size, hid_t dxpl_id, const void *buf);

/* Interface initialization */
static int		interface_initialize_g = 0;
#define INTERFACE_INIT NULL

/* Declare a PQ free list to manage the sieve buffer information */
H5FL_BLK_DEFINE(sieve_buf);

/* Declare the free list to manage blocks of non-zero fill-value data */
H5FL_BLK_DEFINE_STATIC(non_zero_fill);

/* Declare the free list to manage blocks of zero fill-value data */
H5FL_BLK_DEFINE_STATIC(zero_fill);


/*-------------------------------------------------------------------------
 * Function:	H5F_contig_create
 *
 * Purpose:	Allocate file space for a contiguously stored dataset
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *		April 19, 2003
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_contig_create(H5F_t *f, hid_t dxpl_id, struct H5O_layout_t *layout)
{
    hsize_t size;               /* Size of contiguous block of data */
    unsigned u;                 /* Local index variable */
    herr_t ret_value=SUCCEED;   /* Return value */

    FUNC_ENTER_NOAPI(H5F_contig_create, FAIL);

    /* check args */
    assert(f);
    assert(layout);

    /* Compute size */
    size=layout->dim[0];
    for (u = 1; u < layout->ndims; u++)
        size *= layout->dim[u];
    assert (size>0);

    /* Allocate space for the contiguous data */
    if (HADDR_UNDEF==(layout->addr=H5MF_alloc(f, H5FD_MEM_DRAW, dxpl_id, size)))
        HGOTO_ERROR (H5E_IO, H5E_NOSPACE, FAIL, "unable to reserve file space");

done:
    FUNC_LEAVE_NOAPI(ret_value);
} /* end H5F_contig_create */


/*-------------------------------------------------------------------------
 * Function:	H5F_contig_fill
 *
 * Purpose:	Write fill values to a contiguously stored dataset.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *		August 22, 2002
 *
 * Modifications:
 *          Bill Wendling, February 20, 2003
 *          Added support for getting the barrier COMM if you're using
 *          Flexible PHDF5.
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_contig_fill(H5F_t *f, hid_t dxpl_id, struct H5O_layout_t *layout,
    const struct H5S_t *space,
    const struct H5O_fill_t *fill, size_t elmt_size)
{
    hssize_t    snpoints;       /* Number of points in space (for error checking) */
    size_t      npoints;        /* Number of points in space */
    size_t      ptsperbuf;      /* Maximum # of points which fit in the buffer */
    size_t	bufsize=64*1024; /* Size of buffer to write */
    size_t	size;           /* Current # of points to write */
    haddr_t	addr;           /* Offset of dataset */
    void       *buf = NULL;     /* Buffer for fill value writing */
#ifdef H5_HAVE_PARALLEL
    MPI_Comm	mpi_comm=MPI_COMM_NULL;	/* MPI communicator for file */
    int         mpi_rank=(-1);  /* This process's rank  */
    int         mpi_size=(-1);  /* Total # of processes */
    int         mpi_code;       /* MPI return code */
    unsigned    blocks_written=0; /* Flag to indicate that chunk was actually written */
    unsigned    using_mpi=0;    /* Flag to indicate that the file is being accessed with an MPI-capable file driver */
#endif /* H5_HAVE_PARALLEL */
    int         non_zero_fill_f=(-1);   /* Indicate that a non-zero fill-value was used */
    herr_t	ret_value=SUCCEED;	/* Return value */
    
    FUNC_ENTER_NOAPI(H5F_contig_fill, FAIL);

    /* Check args */
    assert(f);
    assert(TRUE==H5P_isa_class(dxpl_id,H5P_DATASET_XFER));
    assert(layout && H5D_CONTIGUOUS==layout->type);
    assert(layout->ndims>0 && layout->ndims<=H5O_LAYOUT_NDIMS);
    assert(H5F_addr_defined(layout->addr));
    assert(space);
    assert(elmt_size>0);

#ifdef H5_HAVE_PARALLEL
    /* Retrieve up MPI parameters */
    if(IS_H5FD_MPIO(f)) {
        /* Get the MPI communicator */
        if (MPI_COMM_NULL == (mpi_comm=H5FD_mpio_communicator(f->shared->lf)))
            HGOTO_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "Can't retrieve MPI communicator");

        /* Get the MPI rank & size */
        if ((mpi_rank=H5FD_mpio_mpi_rank(f->shared->lf))<0)
            HGOTO_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "Can't retrieve MPI rank");
        if ((mpi_size=H5FD_mpio_mpi_size(f->shared->lf))<0)
            HGOTO_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "Can't retrieve MPI size");

        /* Set the MPI-capable file driver flag */
        using_mpi=1;
    } /* end if */
    else if(IS_H5FD_MPIPOSIX(f)) {
        /* Get the MPI communicator */
        if (MPI_COMM_NULL == (mpi_comm=H5FD_mpiposix_communicator(f->shared->lf)))
            HGOTO_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "Can't retrieve MPI communicator");

        /* Get the MPI rank & size */
        if ((mpi_rank=H5FD_mpiposix_mpi_rank(f->shared->lf))<0)
            HGOTO_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "Can't retrieve MPI rank");
        if ((mpi_size=H5FD_mpiposix_mpi_size(f->shared->lf))<0)
            HGOTO_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "Can't retrieve MPI size");

        /* Set the MPI-capable file driver flag */
        using_mpi=1;
    } /* end if */
#ifdef H5_HAVE_FPHDF5
    else if (IS_H5FD_FPHDF5(f)) {
        /* Get the FPHDF5 barrier communicator */
        if (MPI_COMM_NULL == (mpi_comm = H5FD_fphdf5_barrier_communicator(f->shared->lf)))
            HGOTO_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "Can't retrieve MPI communicator");

        /* Get the MPI rank & size */
        if ((mpi_rank = H5FD_fphdf5_mpi_rank(f->shared->lf)) < 0)
            HGOTO_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "Can't retrieve MPI rank");

        if ((mpi_size = H5FD_fphdf5_mpi_size(f->shared->lf)) < 0)
            HGOTO_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "Can't retrieve MPI size");

        /* Set the MPI-capable file driver flag */
        using_mpi = 1;
    } /* end if */
#endif  /* H5_HAVE_FPHDF5 */
#endif  /* H5_HAVE_PARALLEL */

    /* Get the number of elements in the dataset's dataspace */
    snpoints = H5S_get_simple_extent_npoints(space);
    assert(snpoints>=0);
    H5_ASSIGN_OVERFLOW(npoints,snpoints,hssize_t,size_t);

    /* If fill value is not library default, use it to set the element size */
    if(fill->buf)
        elmt_size=fill->size;

    /*
     * Fill the entire current extent with the fill value.  We can do
     * this quite efficiently by making sure we copy the fill value
     * in relatively large pieces.
     */
    ptsperbuf = MAX(1, bufsize/elmt_size);
    bufsize = ptsperbuf*elmt_size;

    /* Fill the buffer with the user's fill value */
    if(fill->buf) {
        /* Allocate temporary buffer */
        if ((buf=H5FL_BLK_MALLOC(non_zero_fill,bufsize))==NULL)
            HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for fill buffer");

        H5V_array_fill(buf, fill->buf, elmt_size, ptsperbuf);

        /* Indicate that a non-zero fill buffer was used */
        non_zero_fill_f=1;
    } /* end if */
    else {      /* Fill the buffer with the default fill value */
        htri_t buf_avail;

        /* Check if there is an already zeroed out buffer available */
        buf_avail=H5FL_BLK_AVAIL(zero_fill,bufsize);
        assert(buf_avail!=FAIL);

        /* Allocate temporary buffer (zeroing it if no buffer is available) */
        if(!buf_avail)
            buf=H5FL_BLK_CALLOC(zero_fill,bufsize);
        else
            buf=H5FL_BLK_MALLOC(zero_fill,bufsize);
        if(buf==NULL)
            HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for fill buffer");

        /* Indicate that a zero fill buffer was used */
        non_zero_fill_f=0;
    } /* end else */
     
    /* Start at the beginning of the dataset */
    addr = layout->addr;

    /* Loop through writing the fill value to the dataset */
    while (npoints>0) {
          size = MIN(ptsperbuf, npoints) * elmt_size;

#ifdef H5_HAVE_PARALLEL
            /* Check if this file is accessed with an MPI-capable file driver */
            if(using_mpi) {
                /* Write the chunks out from only one process */
                /* !! Use the internal "independent" DXPL!! -QAK */
                if(H5_PAR_META_WRITE==mpi_rank) {
                    if (H5F_contig_write(f, (hsize_t)size, addr, size, H5AC_ind_dxpl_id, buf)<0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to write fill value to dataset");
                } /* end if */

                /* Indicate that blocks are being written */
                blocks_written=1;
            } /* end if */
            else {
#endif /* H5_HAVE_PARALLEL */
                H5_CHECK_OVERFLOW(size,size_t,hsize_t);
                if (H5F_contig_write(f, (hsize_t)size, addr, size, dxpl_id, buf)<0)
                    HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to write fill value to dataset");
#ifdef H5_HAVE_PARALLEL
            } /* end else */
#endif /* H5_HAVE_PARALLEL */

          npoints -= MIN(ptsperbuf, npoints);
          addr += size;
      } /* end while */
            
#ifdef H5_HAVE_PARALLEL
    /* Only need to block at the barrier if we actually wrote fill values */
    /* And if we are using an MPI-capable file driver */
    if(using_mpi && blocks_written) {
        /* Wait at barrier to avoid race conditions where some processes are
         * still writing out fill values and other processes race ahead to data
         * in, getting bogus data.
         */
        if (MPI_SUCCESS != (mpi_code=MPI_Barrier(mpi_comm)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Barrier failed", mpi_code);
    } /* end if */
#endif /* H5_HAVE_PARALLEL */

done:
    /* Free the buffer for fill values */
    if (buf) {
        assert(non_zero_fill_f>=0);
        if(non_zero_fill_f)
            H5FL_BLK_FREE(non_zero_fill,buf);
        else
            H5FL_BLK_FREE(zero_fill,buf);
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_contig_delete
 *
 * Purpose:	Delete the file space for a contiguously stored dataset
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *		March 20, 2003
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_contig_delete(H5F_t *f, hid_t dxpl_id, const struct H5O_layout_t *layout)
{
    hsize_t size;               /* Size of contiguous block of data */
    unsigned u;                 /* Local index variable */
    herr_t ret_value=SUCCEED;   /* Return value */

    FUNC_ENTER_NOAPI(H5F_contig_delete, FAIL);

    /* check args */
    assert(f);
    assert(layout);

    /* Compute size */
    size=layout->dim[0];
    for (u = 1; u < layout->ndims; u++)
        size *= layout->dim[u];

    /* Check for overlap with the sieve buffer and reset it */
    if (H5F_sieve_overlap_clear(f, dxpl_id, layout->addr, size)<0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to clear sieve buffer");

    /* Free the file space for the chunk */
    if (H5MF_xfree(f, H5FD_MEM_DRAW, dxpl_id, layout->addr, size)<0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to free object header");

done:
    FUNC_LEAVE_NOAPI(ret_value);
} /* end H5F_contig_delete */


/*-------------------------------------------------------------------------
 * Function:	H5F_contig_write
 *
 * Purpose:	Writes some data from a dataset into a buffer.
 *		The data is contiguous.	 The address is relative to the base
 *		address for the file.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *              Thursday, September 28, 2000
 *
 * Modifications:
 *              Re-written in terms of the new writevv call, QAK, 5/7/03
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5F_contig_write(H5F_t *f, hsize_t max_data, haddr_t addr,
    const size_t size, hid_t dxpl_id, const void *buf)
{
    hsize_t dset_off=0;         /* Offset in dataset */
    hsize_t mem_off=0;          /* Offset in memory */
    size_t dset_len=size;       /* Length in dataset */
    size_t mem_len=size;        /* Length in memory */
    size_t mem_curr_seq=0;      /* "Current sequence" in memory */
    size_t dset_curr_seq=0;     /* "Current sequence" in dataset */
    herr_t ret_value=SUCCEED;   /* Return value */

    FUNC_ENTER_NOAPI(H5F_contig_write, FAIL);

    assert (f);
    assert (buf);

    if (H5F_contig_writevv(f, max_data, addr, 1, &dset_curr_seq, &dset_len, &dset_off, 1, &mem_curr_seq, &mem_len, &mem_off, dxpl_id, buf)<0)
        HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "vector write failed");

done:
    FUNC_LEAVE_NOAPI(ret_value);
}   /* end H5F_contig_write() */


/*-------------------------------------------------------------------------
 * Function:	H5F_contig_readvv
 *
 * Purpose:	Reads some data vectors from a dataset into a buffer.
 *		The data is contiguous.	 The address is the start of the dataset,
 *              relative to the base address for the file and the offsets and
 *              sequence lengths are in bytes.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *              Friday, May 3, 2001
 *
 * Notes:
 *      Offsets in the sequences must be monotonically increasing
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
ssize_t
H5F_contig_readvv(H5F_t *f, hsize_t _max_data, haddr_t _addr,
    size_t dset_max_nseq, size_t *dset_curr_seq, size_t dset_len_arr[], hsize_t dset_offset_arr[],
    size_t mem_max_nseq, size_t *mem_curr_seq, size_t mem_len_arr[], hsize_t mem_offset_arr[],
    hid_t dxpl_id, void *_buf)
{
    unsigned char *buf=(unsigned char *)_buf;      /* Pointer to buffer to fill */
    haddr_t abs_eoa;	        /* Absolute end of file address		*/
    haddr_t rel_eoa;	        /* Relative end of file address		*/
    haddr_t addr;               /* Actual address to read */
    hsize_t max_data;           /* Actual maximum size of data to cache */
    size_t size;                /* Size of sequence in bytes */
    size_t u;                   /* Counting variable */
    size_t v;                   /* Counting variable */
    ssize_t ret_value=0;        /* Return value */
   
    FUNC_ENTER_NOAPI(H5F_contig_readvv, FAIL);

    /* Check args */
    assert(f);
    assert(buf);

    /* Check if data sieving is enabled */
    if(f->shared->lf->feature_flags&H5FD_FEAT_DATA_SIEVE) {
        haddr_t sieve_start, sieve_end;     /* Start & end locations of sieve buffer */
        haddr_t contig_end;             /* End locations of block to write */
        size_t sieve_size;              /* size of sieve buffer */

        /* Set offsets in sequence lists */
        u=*dset_curr_seq;
        v=*mem_curr_seq;

        /* No data sieve buffer yet, go allocate one */
        if(f->shared->sieve_buf==NULL) {
            /* Choose smallest buffer to write */
            if(mem_len_arr[v]<dset_len_arr[u])
                size=mem_len_arr[v];
            else
                size=dset_len_arr[u];

            /* Compute offset on disk */
            addr=_addr+dset_offset_arr[u];

            /* Compute offset in memory */
            buf = (unsigned char *)_buf + mem_offset_arr[v];

            /* Set up the buffer parameters */
            max_data=_max_data-dset_offset_arr[u];

            /* Check if we can actually hold the I/O request in the sieve buffer */
            if(size>f->shared->sieve_buf_size) {
                if (H5F_block_read(f, H5FD_MEM_DRAW, addr, size, dxpl_id, buf)<0)
                    HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "block read failed");
            } /* end if */
            else {
                /* Allocate room for the data sieve buffer */
                if (NULL==(f->shared->sieve_buf=H5FL_BLK_MALLOC(sieve_buf,f->shared->sieve_buf_size)))
                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed");

                /* Determine the new sieve buffer size & location */
                f->shared->sieve_loc=addr;

                /* Make certain we don't read off the end of the file */
                if (HADDR_UNDEF==(abs_eoa=H5FD_get_eoa(f->shared->lf)))
                    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to determine file size");

                /* Adjust absolute EOA address to relative EOA address */
                rel_eoa=abs_eoa-f->shared->base_addr;

                /* Compute the size of the sieve buffer */
                H5_ASSIGN_OVERFLOW(f->shared->sieve_size,MIN(rel_eoa-f->shared->sieve_loc,MIN(max_data,f->shared->sieve_buf_size)),hsize_t,size_t);

                /* Read the new sieve buffer */
                if (H5F_block_read(f, H5FD_MEM_DRAW, f->shared->sieve_loc, f->shared->sieve_size, dxpl_id, f->shared->sieve_buf)<0)
                    HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "block read failed");

                /* Grab the data out of the buffer (must be first piece of data in buffer ) */
                HDmemcpy(buf,f->shared->sieve_buf,size);

                /* Reset sieve buffer dirty flag */
                f->shared->sieve_dirty=0;
            } /* end else */

            /* Update memory information */
            mem_len_arr[v]-=size;
            mem_offset_arr[v]+=size;
            if(mem_len_arr[v]==0)
                v++;

            /* Update file information */
            dset_len_arr[u]-=size;
            dset_offset_arr[u]+=size;
            if(dset_len_arr[u]==0)
                u++;

            /* Increment number of bytes copied */
            ret_value+=size;
        } /* end if */

        /* Stash local copies of these value */
        sieve_start=f->shared->sieve_loc;
        sieve_size=f->shared->sieve_size;
        sieve_end=sieve_start+sieve_size;
        
        /* Works through sequences as fast as possible */
        for(; u<dset_max_nseq && v<mem_max_nseq; ) {
            /* Choose smallest buffer to write */
            if(mem_len_arr[v]<dset_len_arr[u])
                size=mem_len_arr[v];
            else
                size=dset_len_arr[u];

            /* Compute offset on disk */
            addr=_addr+dset_offset_arr[u];

            /* Compute offset in memory */
            buf = (unsigned char *)_buf + mem_offset_arr[v];

            /* Compute end of sequence to retrieve */
            contig_end=addr+size-1;

            /* If entire read is within the sieve buffer, read it from the buffer */
            if(addr>=sieve_start && contig_end<sieve_end) {
                unsigned char *base_sieve_buf=f->shared->sieve_buf+(addr-sieve_start);

                /* Grab the data out of the buffer */
                HDmemcpy(buf,base_sieve_buf,size);
            } /* end if */
            /* Entire request is not within this data sieve buffer */
            else {
                /* Check if we can actually hold the I/O request in the sieve buffer */
                if(size>f->shared->sieve_buf_size) {
                    /* Check for any overlap with the current sieve buffer */
                    if((sieve_start>=addr && sieve_start<(contig_end+1))
                            || ((sieve_end-1)>=addr && (sieve_end-1)<(contig_end+1))) {
                        /* Flush the sieve buffer, if it's dirty */
                        if(f->shared->sieve_dirty) {
                            /* Write to file */
                            if (H5F_block_write(f, H5FD_MEM_DRAW, sieve_start, sieve_size, dxpl_id, f->shared->sieve_buf)<0)
                                HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed");

                            /* Reset sieve buffer dirty flag */
                            f->shared->sieve_dirty=0;
                        } /* end if */
                    } /* end if */

                    /* Read directly into the user's buffer */
                    if (H5F_block_read(f, H5FD_MEM_DRAW, addr, size, dxpl_id, buf)<0)
                        HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "block read failed");
                } /* end if */
                /* Element size fits within the buffer size */
                else {
                    /* Flush the sieve buffer if it's dirty */
                    if(f->shared->sieve_dirty) {
                        /* Write to file */
                        if (H5F_block_write(f, H5FD_MEM_DRAW, sieve_start, sieve_size, dxpl_id, f->shared->sieve_buf)<0)
                            HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed");

                        /* Reset sieve buffer dirty flag */
                        f->shared->sieve_dirty=0;
                    } /* end if */

                    /* Determine the new sieve buffer size & location */
                    f->shared->sieve_loc=addr;

                    /* Make certain we don't read off the end of the file */
                    if (HADDR_UNDEF==(abs_eoa=H5FD_get_eoa(f->shared->lf)))
                        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to determine file size");

                    /* Adjust absolute EOA address to relative EOA address */
                    rel_eoa=abs_eoa-f->shared->base_addr;

                    /* Only need this when resizing sieve buffer */
                    max_data=_max_data-dset_offset_arr[u];

                    /* Compute the size of the sieve buffer */
                    /* Don't read off the end of the file, don't read past the end of the data element and don't read more than the buffer size */
                    H5_ASSIGN_OVERFLOW(f->shared->sieve_size,MIN(rel_eoa-f->shared->sieve_loc,MIN(max_data,f->shared->sieve_buf_size)),hsize_t,size_t);

                    /* Update local copies of sieve information */
                    sieve_start=f->shared->sieve_loc;
                    sieve_size=f->shared->sieve_size;
                    sieve_end=sieve_start+sieve_size;

                    /* Read the new sieve buffer */
                    if (H5F_block_read(f, H5FD_MEM_DRAW, f->shared->sieve_loc, f->shared->sieve_size, dxpl_id, f->shared->sieve_buf)<0)
                        HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "block read failed");

                    /* Grab the data out of the buffer (must be first piece of data in buffer ) */
                    HDmemcpy(buf,f->shared->sieve_buf,size);

                    /* Reset sieve buffer dirty flag */
                    f->shared->sieve_dirty=0;
                } /* end else */
            } /* end else */

            /* Update memory information */
            mem_len_arr[v]-=size;
            mem_offset_arr[v]+=size;
            if(mem_len_arr[v]==0)
                v++;

            /* Update file information */
            dset_len_arr[u]-=size;
            dset_offset_arr[u]+=size;
            if(dset_len_arr[u]==0)
                u++;

            /* Increment number of bytes copied */
            ret_value+=size;
        } /* end for */
    } /* end if */
    else {
        /* Work through all the sequences */
        for(u=*dset_curr_seq, v=*mem_curr_seq; u<dset_max_nseq && v<mem_max_nseq; ) {
            /* Choose smallest buffer to write */
            if(mem_len_arr[v]<dset_len_arr[u])
                size=mem_len_arr[v];
            else
                size=dset_len_arr[u];

            /* Compute offset on disk */
            addr=_addr+dset_offset_arr[u];

            /* Compute offset in memory */
            buf = (unsigned char *)_buf + mem_offset_arr[v];

            /* Write data */
            if (H5F_block_read(f, H5FD_MEM_DRAW, addr, size, dxpl_id, buf)<0)
                HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed");

            /* Update memory information */
            mem_len_arr[v]-=size;
            mem_offset_arr[v]+=size;
            if(mem_len_arr[v]==0)
                v++;

            /* Update file information */
            dset_len_arr[u]-=size;
            dset_offset_arr[u]+=size;
            if(dset_len_arr[u]==0)
                u++;

            /* Increment number of bytes copied */
            ret_value+=size;
        } /* end for */
    } /* end else */

    /* Update current sequence vectors */
    *dset_curr_seq=u;
    *mem_curr_seq=v;

done:
    FUNC_LEAVE_NOAPI(ret_value);
}   /* end H5F_contig_readvv() */


/*-------------------------------------------------------------------------
 * Function:	H5F_contig_writevv
 *
 * Purpose:	Writes some data vectors into a dataset from vectors into a
 *              buffer.  The address is the start of the dataset,
 *              relative to the base address for the file and the offsets and
 *              sequence lengths are in bytes.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *              Friday, May 2, 2003
 *
 * Notes:
 *      Offsets in the sequences must be monotonically increasing
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
ssize_t
H5F_contig_writevv(H5F_t *f, hsize_t _max_data, haddr_t _addr,
    size_t dset_max_nseq, size_t *dset_curr_seq, size_t dset_len_arr[], hsize_t dset_offset_arr[],
    size_t mem_max_nseq, size_t *mem_curr_seq, size_t mem_len_arr[], hsize_t mem_offset_arr[],
    hid_t dxpl_id, const void *_buf)
{
    const unsigned char *buf=_buf;      /* Pointer to buffer to fill */
    haddr_t abs_eoa;	        /* Absolute end of file address		*/
    haddr_t rel_eoa;	        /* Relative end of file address		*/
    haddr_t addr;               /* Actual address to read */
    hsize_t max_data;           /* Actual maximum size of data to cache */
    size_t size;                /* Size of sequence in bytes */
    size_t u;                   /* Counting variable */
    size_t v;                   /* Counting variable */
    ssize_t ret_value=0;        /* Return value */
   
    FUNC_ENTER_NOAPI(H5F_contig_writevv, FAIL);

    /* Check args */
    assert(f);
    assert(buf);

    /* Check if data sieving is enabled */
    if(f->shared->lf->feature_flags&H5FD_FEAT_DATA_SIEVE) {
        haddr_t sieve_start, sieve_end;     /* Start & end locations of sieve buffer */
        haddr_t contig_end;             /* End locations of block to write */
        size_t sieve_size;              /* size of sieve buffer */

        /* Set offsets in sequence lists */
        u=*dset_curr_seq;
        v=*mem_curr_seq;

        /* No data sieve buffer yet, go allocate one */
        if(f->shared->sieve_buf==NULL) {
            /* Choose smallest buffer to write */
            if(mem_len_arr[v]<dset_len_arr[u])
                size=mem_len_arr[v];
            else
                size=dset_len_arr[u];

            /* Compute offset on disk */
            addr=_addr+dset_offset_arr[u];

            /* Compute offset in memory */
            buf = (const unsigned char *)_buf + mem_offset_arr[v];

            /* Set up the buffer parameters */
            max_data=_max_data-dset_offset_arr[u];

            /* Check if we can actually hold the I/O request in the sieve buffer */
            if(size>f->shared->sieve_buf_size) {
                if (H5F_block_write(f, H5FD_MEM_DRAW, addr, size, dxpl_id, buf)<0)
                    HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed");
            } /* end if */
            else {
                /* Allocate room for the data sieve buffer */
                if (NULL==(f->shared->sieve_buf=H5FL_BLK_MALLOC(sieve_buf,f->shared->sieve_buf_size)))
                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed");

                /* Determine the new sieve buffer size & location */
                f->shared->sieve_loc=addr;

                /* Make certain we don't read off the end of the file */
                if (HADDR_UNDEF==(abs_eoa=H5FD_get_eoa(f->shared->lf)))
                    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to determine file size");

                /* Adjust absolute EOA address to relative EOA address */
                rel_eoa=abs_eoa-f->shared->base_addr;

                /* Compute the size of the sieve buffer */
                H5_ASSIGN_OVERFLOW(f->shared->sieve_size,MIN(rel_eoa-f->shared->sieve_loc,MIN(max_data,f->shared->sieve_buf_size)),hsize_t,size_t);

                /* Check if there is any point in reading the data from the file */
                if(f->shared->sieve_size>size) {
                    /* Read the new sieve buffer */
                    if (H5F_block_read(f, H5FD_MEM_DRAW, f->shared->sieve_loc, f->shared->sieve_size, dxpl_id, f->shared->sieve_buf)<0)
                        HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "block read failed");
                } /* end if */

                /* Grab the data out of the buffer (must be first piece of data in buffer ) */
                HDmemcpy(f->shared->sieve_buf,buf,size);

                /* Set sieve buffer dirty flag */
                f->shared->sieve_dirty=1;
            } /* end else */

            /* Update memory information */
            mem_len_arr[v]-=size;
            mem_offset_arr[v]+=size;
            if(mem_len_arr[v]==0)
                v++;

            /* Update file information */
            dset_len_arr[u]-=size;
            dset_offset_arr[u]+=size;
            if(dset_len_arr[u]==0)
                u++;

            /* Increment number of bytes copied */
            ret_value+=size;
        } /* end if */

        /* Stash local copies of these value */
        sieve_start=f->shared->sieve_loc;
        sieve_size=f->shared->sieve_size;
        sieve_end=sieve_start+sieve_size;
        
        /* Works through sequences as fast as possible */
        for(; u<dset_max_nseq && v<mem_max_nseq; ) {
            /* Choose smallest buffer to write */
            if(mem_len_arr[v]<dset_len_arr[u])
                size=mem_len_arr[v];
            else
                size=dset_len_arr[u];

            /* Compute offset on disk */
            addr=_addr+dset_offset_arr[u];

            /* Compute offset in memory */
            buf = (const unsigned char *)_buf + mem_offset_arr[v];

            /* Compute end of sequence to retrieve */
            contig_end=addr+size-1;

            /* If entire write is within the sieve buffer, write it to the buffer */
            if(addr>=sieve_start && contig_end<sieve_end) {
                unsigned char *base_sieve_buf=f->shared->sieve_buf+(addr-sieve_start);

                /* Put the data into the sieve buffer */
                HDmemcpy(base_sieve_buf,buf,size);

                /* Set sieve buffer dirty flag */
                f->shared->sieve_dirty=1;

            } /* end if */
            /* Entire request is not within this data sieve buffer */
            else {
                /* Check if we can actually hold the I/O request in the sieve buffer */
                if(size>f->shared->sieve_buf_size) {
                    /* Check for any overlap with the current sieve buffer */
                    if((sieve_start>=addr && sieve_start<(contig_end+1))
                            || ((sieve_end-1)>=addr && (sieve_end-1)<(contig_end+1))) {
                        /* Flush the sieve buffer, if it's dirty */
                        if(f->shared->sieve_dirty) {
                            /* Write to file */
                            if (H5F_block_write(f, H5FD_MEM_DRAW, sieve_start, sieve_size, dxpl_id, f->shared->sieve_buf)<0)
                                HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed");

                            /* Reset sieve buffer dirty flag */
                            f->shared->sieve_dirty=0;
                        } /* end if */

                        /* Force the sieve buffer to be re-read the next time */
                        f->shared->sieve_loc=HADDR_UNDEF;
                        f->shared->sieve_size=0;
                    } /* end if */

                    /* Write directly from the user's buffer */
                    if (H5F_block_write(f, H5FD_MEM_DRAW, addr, size, dxpl_id, buf)<0)
                        HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed");
                } /* end if */
                /* Element size fits within the buffer size */
                else {
                    /* Check if it is possible to (exactly) prepend or append to existing (dirty) sieve buffer */
                    if(((addr+size)==sieve_start || addr==sieve_end) &&
                            (size+sieve_size)<=f->shared->sieve_buf_size &&
                            f->shared->sieve_dirty) {
                        /* Prepend to existing sieve buffer */
                        if((addr+size)==sieve_start) {
                            /* Move existing sieve information to correct location */
                            HDmemmove(f->shared->sieve_buf+size,f->shared->sieve_buf,sieve_size);

                            /* Copy in new information (must be first in sieve buffer) */
                            HDmemcpy(f->shared->sieve_buf,buf,size);

                            /* Adjust sieve location */
                            f->shared->sieve_loc=addr;
                            
                        } /* end if */
                        /* Append to existing sieve buffer */
                        else {
                            /* Copy in new information */
                            HDmemcpy(f->shared->sieve_buf+sieve_size,buf,size);
                        } /* end else */

                        /* Adjust sieve size */
                        f->shared->sieve_size += size;
                        
                        /* Update local copies of sieve information */
                        sieve_start=f->shared->sieve_loc;
                        sieve_size=f->shared->sieve_size;
                        sieve_end=sieve_start+sieve_size;

                    } /* end if */
                    /* Can't add the new data onto the existing sieve buffer */
                    else {
                        /* Flush the sieve buffer if it's dirty */
                        if(f->shared->sieve_dirty) {
                            /* Write to file */
                            if (H5F_block_write(f, H5FD_MEM_DRAW, sieve_start, sieve_size, dxpl_id, f->shared->sieve_buf)<0)
                                HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed");

                            /* Reset sieve buffer dirty flag */
                            f->shared->sieve_dirty=0;
                        } /* end if */

                        /* Determine the new sieve buffer size & location */
                        f->shared->sieve_loc=addr;

                        /* Make certain we don't read off the end of the file */
                        if (HADDR_UNDEF==(abs_eoa=H5FD_get_eoa(f->shared->lf)))
                            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to determine file size");

                        /* Adjust absolute EOA address to relative EOA address */
                        rel_eoa=abs_eoa-f->shared->base_addr;

                        /* Only need this when resizing sieve buffer */
                        max_data=_max_data-dset_offset_arr[u];

                        /* Compute the size of the sieve buffer */
                        /* Don't read off the end of the file, don't read past the end of the data element and don't read more than the buffer size */
                        H5_ASSIGN_OVERFLOW(f->shared->sieve_size,MIN(rel_eoa-f->shared->sieve_loc,MIN(max_data,f->shared->sieve_buf_size)),hsize_t,size_t);

                        /* Update local copies of sieve information */
                        sieve_start=f->shared->sieve_loc;
                        sieve_size=f->shared->sieve_size;
                        sieve_end=sieve_start+sieve_size;

                        /* Check if there is any point in reading the data from the file */
                        if(f->shared->sieve_size>size) {
                            /* Read the new sieve buffer */
                            if (H5F_block_read(f, H5FD_MEM_DRAW, f->shared->sieve_loc, f->shared->sieve_size, dxpl_id, f->shared->sieve_buf)<0)
                                HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "block read failed");
                        } /* end if */

                        /* Grab the data out of the buffer (must be first piece of data in buffer ) */
                        HDmemcpy(f->shared->sieve_buf,buf,size);

                        /* Set sieve buffer dirty flag */
                        f->shared->sieve_dirty=1;

                    } /* end else */
                } /* end else */
            } /* end else */

            /* Update memory information */
            mem_len_arr[v]-=size;
            mem_offset_arr[v]+=size;
            if(mem_len_arr[v]==0)
                v++;

            /* Update file information */
            dset_len_arr[u]-=size;
            dset_offset_arr[u]+=size;
            if(dset_len_arr[u]==0)
                u++;

            /* Increment number of bytes copied */
            ret_value+=size;
        } /* end for */
    } /* end if */
    else {
        /* Work through all the sequences */
        for(u=*dset_curr_seq, v=*mem_curr_seq; u<dset_max_nseq && v<mem_max_nseq; ) {
            /* Choose smallest buffer to write */
            if(mem_len_arr[v]<dset_len_arr[u])
                size=mem_len_arr[v];
            else
                size=dset_len_arr[u];

            /* Compute offset on disk */
            addr=_addr+dset_offset_arr[u];

            /* Compute offset in memory */
            buf = (const unsigned char *)_buf + mem_offset_arr[v];

            /* Write data */
            if (H5F_block_write(f, H5FD_MEM_DRAW, addr, size, dxpl_id, buf)<0)
                HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed");

            /* Update memory information */
            mem_len_arr[v]-=size;
            mem_offset_arr[v]+=size;
            if(mem_len_arr[v]==0)
                v++;

            /* Update file information */
            dset_len_arr[u]-=size;
            dset_offset_arr[u]+=size;
            if(dset_len_arr[u]==0)
                u++;

            /* Increment number of bytes copied */
            ret_value+=size;
        } /* end for */
    } /* end else */

    /* Update current sequence vectors */
    *dset_curr_seq=u;
    *mem_curr_seq=v;

done:
    FUNC_LEAVE_NOAPI(ret_value);
}   /* end H5F_contig_writevv() */